<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE article PUBLIC "-//NLM//DTD Journal Publishing DTD v2.3 20070202//EN" "journalpublishing.dtd">
<article xml:lang="EN" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" article-type="research-article">
<front>
<journal-meta>
<journal-id journal-id-type="publisher-id">Front. Cardiovasc. Med.</journal-id>
<journal-title>Frontiers in Cardiovascular Medicine</journal-title>
<abbrev-journal-title abbrev-type="pubmed">Front. Cardiovasc. Med.</abbrev-journal-title>
<issn pub-type="epub">2297-055X</issn>
<publisher>
<publisher-name>Frontiers Media S.A.</publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id pub-id-type="doi">10.3389/fcvm.2022.1104357</article-id>
<article-categories>
<subj-group subj-group-type="heading">
<subject>Cardiovascular Medicine</subject>
<subj-group>
<subject>Original Research</subject>
</subj-group>
</subj-group>
</article-categories>
<title-group>
<article-title>Meta-analysis of extracorporeal membrane oxygenation in combination with intra-aortic balloon pump vs. extracorporeal membrane oxygenation only in patients with cardiogenic shock due to acute myocardial infarction</article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name><surname>Meertens</surname> <given-names>Max M.</given-names></name>
<xref ref-type="author-notes" rid="fn002"><sup>&#x2020;</sup></xref>
</contrib>
<contrib contrib-type="author">
<name><surname>Tichelb&#x00E4;cker</surname> <given-names>Tobias</given-names></name>
<xref ref-type="author-notes" rid="fn002"><sup>&#x2020;</sup></xref>
<uri xlink:href="http://loop.frontiersin.org/people/2106746/overview"/>
</contrib>
<contrib contrib-type="author">
<name><surname>Macherey-Meyer</surname> <given-names>Sascha</given-names></name>
</contrib>
<contrib contrib-type="author">
<name><surname>Heyne</surname> <given-names>Sebastian</given-names></name>
</contrib>
<contrib contrib-type="author">
<name><surname>Braumann</surname> <given-names>Simon</given-names></name>
<uri xlink:href="http://loop.frontiersin.org/people/564594/overview"/>
</contrib>
<contrib contrib-type="author">
<name><surname>Nie&#x00DF;en</surname> <given-names>Stephan F.</given-names></name>
</contrib>
<contrib contrib-type="author">
<name><surname>Baldus</surname> <given-names>Stephan</given-names></name>
</contrib>
<contrib contrib-type="author">
<name><surname>Adler</surname> <given-names>Christoph</given-names></name>
<xref ref-type="author-notes" rid="fn003"><sup>&#x2021;</sup></xref>
<uri xlink:href="http://loop.frontiersin.org/people/1302806/overview"/>
</contrib>
<contrib contrib-type="author" corresp="yes">
<name><surname>Lee</surname> <given-names>Samuel</given-names></name>
<xref ref-type="corresp" rid="c001"><sup>&#x002A;</sup></xref>
<xref ref-type="author-notes" rid="fn003"><sup>&#x2021;</sup></xref>
<uri xlink:href="http://loop.frontiersin.org/people/1251122/overview"/>
</contrib>
</contrib-group>
<aff><institution>Faculty of Medicine, Clinic III for Internal Medicine, University Hospital Cologne, University of Cologne</institution>, <addr-line>Cologne</addr-line>, <country>Germany</country></aff>
<author-notes>
<fn fn-type="edited-by"><p>Edited by: Sebastian Ludwig, University Medical Center Hamburg-Eppendorf, Germany</p></fn>
<fn fn-type="edited-by"><p>Reviewed by: Benedikt Schrage, University Medical Center Hamburg-Eppendorf, Germany; Karl-Philipp Rommel, Cardiovascular Research Foundation, United States</p></fn>
<corresp id="c001">&#x002A;Correspondence: Samuel Lee, <email>samuel.lee@uk-koeln.de</email></corresp>
<fn fn-type="equal" id="fn002"><p><sup>&#x2020;</sup>These authors have contributed equally to this work and share first authorship</p></fn>
<fn fn-type="equal" id="fn003"><p><sup>&#x2021;</sup>These authors have contributed equally to this work and share last authorship</p></fn>
<fn fn-type="other" id="fn004"><p>This article was submitted to Structural Interventional Cardiology, a section of the journal Frontiers in Cardiovascular Medicine</p></fn>
</author-notes>
<pub-date pub-type="epub">
<day>18</day>
<month>01</month>
<year>2023</year>
</pub-date>
<pub-date pub-type="collection">
<year>2022</year>
</pub-date>
<volume>9</volume>
<elocation-id>1104357</elocation-id>
<history>
<date date-type="received">
<day>21</day>
<month>11</month>
<year>2022</year>
</date>
<date date-type="accepted">
<day>29</day>
<month>12</month>
<year>2022</year>
</date>
</history>
<permissions>
<copyright-statement>Copyright &#x00A9; 2023 Meertens, Tichelb&#x00E4;cker, Macherey-Meyer, Heyne, Braumann, Nie&#x00DF;en, Baldus, Adler and Lee.</copyright-statement>
<copyright-year>2023</copyright-year>
<copyright-holder>Meertens, Tichelb&#x00E4;cker, Macherey-Meyer, Heyne, Braumann, Nie&#x00DF;en, Baldus, Adler and Lee</copyright-holder>
<license xlink:href="http://creativecommons.org/licenses/by/4.0/"><p>This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.</p></license>
</permissions>
<abstract>
<sec>
<title>Background</title>
<p>Incidence and mortality of cardiogenic shock (CS) in patients with acute myocardial infarction (AMI) remain high despite substantial therapy improvements in acute percutaneous coronary intervention over the last decades. Unloading the left ventricle in patients with Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) can be performed by using an intra-aortic balloon pumps&#x2019; (IABP) afterload reduction, which might be especially beneficial in AMI patients with CS.</p>
</sec>
<sec>
<title>Objective</title>
<p>The objective of this meta-analysis was to assess the effect of VA-ECMO + IABP vs. VA-ECMO treatment on the mortality of patients with CS due to AMI.</p>
</sec>
<sec>
<title>Methods</title>
<p>A systematic literature search was performed using EMBASE, COCHRANE, and MEDLINE databases. Studies comparing the effect of VA-ECMO + IABP vs. VA-ECMO on mortality of patients with AMI were included. Meta-analyses were performed to analyze the effect of the chosen treatment on 30-day/in-hospital mortality.</p>
</sec>
<sec>
<title>Results</title>
<p>Twelve studies were identified by the literature search, including a total of 5,063 patients, 81.5% were male and the mean age was 65.9 years. One thousand one hundred and thirty-six patients received treatment with VA-ECMO in combination with IABP and 2,964 patients received VA-ECMO treatment only. The performed meta-analysis showed decreased mortality at 30-days/in-hospital after VA-ECMO + IABP compared to VA-ECMO only for patients with cardiogenic shock after AMI (OR 0.36, 95% CI 0.30&#x2013;0.44, <italic>P</italic>&#x2264;0.001). Combination of VA-ECMO + IABP was associated with higher rates of weaning success (OR 0.29, 95% CI 0.16&#x2013;0.53, <italic>P</italic> &#x003C; 0.001) without an increase of vascular access complications (OR 0.85, 95% CI 0.35&#x2013;2.08, <italic>P</italic> = 0.72).</p>
</sec>
<sec>
<title>Conclusion</title>
<p>In this meta-analysis, combination therapy of VA-ECMO + IABP was superior to VA-ECMO only therapy in patients with CS due to AMI. In the absence of randomized data, these results are hypothesis generating only.</p>
</sec>
</abstract>
<kwd-group>
<kwd>VA-ECMO</kwd>
<kwd>IABP</kwd>
<kwd>cardiogenic shock</kwd>
<kwd>acute coronary syndrome (ACS)</kwd>
<kwd>meta-analysis</kwd>
</kwd-group>
<counts>
<fig-count count="5"/>
<table-count count="2"/>
<equation-count count="0"/>
<ref-count count="47"/>
<page-count count="9"/>
<word-count count="5555"/>
</counts>
</article-meta>
</front>
<body>
<sec id="S1" sec-type="intro">
<title>Introduction</title>
<p>Cardiogenic shock (CS) describes a clinical condition of inadequate tissue or end-organ perfusion due to acute heart failure. The predominant cause of CS is acute myocardial infarction (AMI). CS occurs in 5&#x2013;10% of patients with AMI and is associated with very poor prognosis (30-day mortality of approximately 40%) (<xref ref-type="bibr" rid="B1">1</xref>). In the United States, 40,000&#x2013;50,000 patients are suffering from CS each year and incidence of cardiogenic shock in Europe is rising (<xref ref-type="bibr" rid="B2">2</xref>, <xref ref-type="bibr" rid="B3">3</xref>). Despite several improvements in treatment of AMI patients in the last two decades including new stent technologies, reperfusion strategies, or pharmacological options, mortality rates in CS are still unacceptably high (<xref ref-type="bibr" rid="B4">4</xref>).</p>
<p>Mechanical circulatory support (MCS) systems, such as veno-arterial extracorporeal membrane oxygenation (VA-ECMO), were implemented in clinical practice at specialized cardiac arrest centers to improve prognosis of CS patients (<xref ref-type="bibr" rid="B5">5</xref>). The European Society of Cardiology guidelines give the use of MCS in CS a IIa C recommendation (<xref ref-type="bibr" rid="B6">6</xref>). Therefore, VA-ECMO therapy is widely used in patients with CS (<xref ref-type="bibr" rid="B2">2</xref>, <xref ref-type="bibr" rid="B7">7</xref>). However, this approach lacks robust clinical evidence based on randomized data and entails disadvantageous hemodynamics in CS. Retrograde flow in the aorta through the aortic cannula increases left ventricular (LV) afterload which leads to increased LV enddiastolic pressure, left atrial pressure, and pulmonary capillary wedge pressure. This results in a worsening of blood oxygen saturation, an increase in myocardial oxygen demand, and a deterioration of coronary circulation which consequently leads to worsening of myocardial infarction (<xref ref-type="bibr" rid="B8">8</xref>). Therefore, the AMI population differs substantially from other VA-ECMO treated patients and so called &#x201C;venting&#x201D; strategies may play an essential role in treatment of AMI patients with VA-ECMO.</p>
<p>Due to these potentially harmful effects of VA-ECMO therapy especially in patients with CS due to AMI, mainly two &#x201C;venting&#x201D; strategies are being used to unload the left ventricle: reducing LV preload with ECMO + a transvalvular microaxial flow pump (Impella, Abiomed, Danvers, MA, USA) and reducing LV afterload with ECMO + an intra-aortic balloon pump (IABP) (<xref ref-type="bibr" rid="B9">9</xref>). Combination of VA-ECMO + transvalvular microaxial flow pump is currently investigated in a randomized controlled trial (RCT) in CS patients (<xref ref-type="bibr" rid="B10">10</xref>). As there is no RCT investigating VA-ECMO + IABP vs. VA-ECMO only, we conducted this meta-analysis to explore whether combination of VA-ECMO + IABP may benefit patients in CS due to AMI compared to VA-ECMO only therapy.</p>
</sec>
<sec id="S2" sec-type="materials|methods">
<title>Materials and methods</title>
<sec id="S2.SS1">
<title>Literature search and study selection</title>
<p>The systematic review was performed according to a pre-specified protocol and an explicit, reproducible plan for literature research and synthesis as demanded by the Preferred Reporting Items of Systematic Reviews and Meta-Analyses (PRISMA) guidelines (<xref ref-type="bibr" rid="B11">11</xref>). The Medline, Cochrane and Embase databases were searched by two authors (MM and TT) in September 2021. Results were updated again on December 11, 2022. The following mesh terms and medical subheadings were used: st elevation myocardial infarction, acute myocardial infarction, myocardial infarction, myocardial ischemia, myocardial infarction [MeSH Term], STEMI, IABP, intra-aortic balloon pumping, intraaortic balloon pumping, intraaortic balloon pumping, counterpulsation device, extracorporeal life support, extracorporeal membrane oxygenation, extra corporeal membrane oxygenation, ecmo [MeSH Term], ECMO, cardiogenic shock, and cardiogenic shock [MeSH Term].</p>
<p>The study selection was conducted by two reviewers (MM and TT). In case of a disagreement, this was solved by consensus with the senior author (SL). Retrieved records retrieved were screened using the title and abstract by both researchers. Eligibility assessment of the full text was considered if the title or abstract seemed eligible. The applied in- and exclusion criteria are described below. The database search was supplemented by scanning the references of the included studies. Irrespective of the study design all studies were included in the systematic review and meta-analysis, if they met the following inclusion criteria: (1) A full text had to be accessible, (2) the studied participants had to be human patients, (3) studies had to involve patients treated for cardiogenic shock after myocardial infarction, even if it was just a subgroup, and (4) studies had to include patients treated by VA-ECMO and patients treated by VA-ECMO + IABP. We excluded studies which did not report absolute values for in-hospital/30-day mortality for both groups.</p>
</sec>
<sec id="S2.SS2">
<title>Data collection</title>
<p>Eligible data was retrieved by a researcher and verified by a second one for every study (MM and TT). We extracted the following data from each study: first author, country of the institution of the first author, year of publication, study design, size of study population, mean age, percentage of male patients, prevalence of hypertension, diabetes mellitus, peripheral arterial disease, prior stroke, ischemic heart disease, number of implanted stents, location of culprit lesion, reason for IABP usage, number of patients treated with VA-ECMO, and number of patients treated with VA-ECMO + IABP. For both groups we collected the in-hospital/30-day mortality and the incidence of ischemic and bleeding complications. The methodological quality of all included studies was assessed using the checklist recommended by the 9-point Newcastle&#x2013;Ottawa scale (NOS) (<xref ref-type="bibr" rid="B12">12</xref>).</p>
</sec>
<sec id="S2.SS3">
<title>Statistical analysis</title>
<p>Meta-analyses were performed to compare in-hospital/30-day mortality and incidence of ischemic and bleeding complications of patients treated with VA-ECMO and of patients treated with VA-ECMO + IABP. Fixed effects meta-analyses were performed using the Mantel&#x2013;Haenszel method for dichotomous data to estimate the pooled odds ratio (OR). Statistical heterogeneity was assessed using <italic>I</italic><sup>2</sup> statistics. An <italic>I</italic><sup>2</sup> value of more than 75% was considered to indicate a significant heterogeneity. A possible publication bias was assessed and represented by a funnel plot. <italic>P</italic>-values &#x003C; 0.05 were considered statistically significant. The meta-analysis was performed using in RevMan (version 7.3).</p>
</sec>
</sec>
<sec id="S3" sec-type="results">
<title>Results</title>
<p>The search strategy led to 924 results in December 2022 after updating the initial search from September 2021. Removal of duplicates resulted in 555 studies potentially eligible for analysis. Another 535 were removed, because they did not meet the inclusion criteria. Five studies were removed after full text analysis due to lack of explicit mortality data for subgroups or because all patients were treated with VA-ECMO + IABP (<xref ref-type="bibr" rid="B13">13</xref>&#x2013;<xref ref-type="bibr" rid="B17">17</xref>). Two more were removed as an ECMO only strategy was compared to ECMO + IABP/Impella or + IABP/pVAD (<xref ref-type="bibr" rid="B18">18</xref>, <xref ref-type="bibr" rid="B19">19</xref>). One further registry from Japan was excluded as it included less patients than the Japanese registry study we included (<xref ref-type="bibr" rid="B20">20</xref>). Four studies were identified by additional records. Finally, 12 studies were included for qualitative and quantitative analysis (<xref ref-type="fig" rid="F1">Figure 1</xref>; <xref ref-type="bibr" rid="B21">21</xref>&#x2013;<xref ref-type="bibr" rid="B32">32</xref>). None of these were randomized controlled trials but 11 were case series and one was a national register (<xref ref-type="table" rid="T1">Table 1</xref>). Seven studies were conducted in Asia (<xref ref-type="bibr" rid="B21">21</xref>&#x2013;<xref ref-type="bibr" rid="B25">25</xref>, <xref ref-type="bibr" rid="B29">29</xref>, <xref ref-type="bibr" rid="B30">30</xref>), three in Europe (<xref ref-type="bibr" rid="B26">26</xref>, <xref ref-type="bibr" rid="B28">28</xref>, <xref ref-type="bibr" rid="B32">32</xref>), and one in the US and Australia (<xref ref-type="bibr" rid="B27">27</xref>, <xref ref-type="bibr" rid="B31">31</xref>). In total 5,063 patients with cardiogenic shock after myocardial infarction were included, 1,136 patients were treated with VA-ECMO and 3,927 received VA-ECMO and IABP. The methodological quality of all included studies according to the 9-point Newcastle-Ottawa scale is presented in <xref ref-type="table" rid="T1">Table 1</xref>. All studies showed an acceptable score.</p>
<fig id="F1" position="float">
<label>FIGURE 1</label>
<caption><p>Search flow chart according to PRISMA guidelines.</p></caption>
<graphic mimetype="image" mime-subtype="tiff" xlink:href="fcvm-09-1104357-g001.tif"/>
</fig>
<table-wrap position="float" id="T1">
<label>TABLE 1</label>
<caption><p>Assessment of the Newcastle Ottawa scale.</p></caption>
<table cellspacing="5" cellpadding="5" frame="box" rules="all">
<thead>
<tr>
<td valign="top" align="left" style="color:#ffffff;background-color: #7f8080;">Study</td>
<td valign="top" align="center" style="color:#ffffff;background-color: #7f8080;">Representativeness of the exposed cohort</td>
<td valign="top" align="center" style="color:#ffffff;background-color: #7f8080;">Ascertainment of exposure</td>
<td valign="top" align="center" style="color:#ffffff;background-color: #7f8080;">Ascertainment of exposure</td>
<td valign="top" align="center" style="color:#ffffff;background-color: #7f8080;">Outcome of interest not present at the start of study</td>
<td valign="top" align="center" style="color:#ffffff;background-color: #7f8080;">Cohorts comparable on the basis of design or analysis</td>
<td valign="top" align="center" style="color:#ffffff;background-color: #7f8080;">Assessment of outcome</td>
<td valign="top" align="center" style="color:#ffffff;background-color: #7f8080;">Adequacy of duration of follow-up</td>
<td valign="top" align="center" style="color:#ffffff;background-color: #7f8080;">Adequacy of completeness of follow-up</td>
</tr>
</thead>
<tbody>
<tr>
<td valign="top" align="left">Aoyama</td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td/>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
</tr>
<tr>
<td valign="top" align="left">Chen</td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td/>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
</tr>
<tr>
<td valign="top" align="left">Chung</td>
<td/>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td/>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
</tr>
<tr>
<td valign="top" align="left">Kagawa</td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td/>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
</tr>
<tr>
<td valign="top" align="left">Mueller</td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td/>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
</tr>
<tr>
<td valign="top" align="left">Overtchouk</td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td/>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
</tr>
<tr>
<td valign="top" align="left">Park</td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td/>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
</tr>
<tr>
<td valign="top" align="left">Sakamoto</td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td/>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
</tr>
<tr>
<td valign="top" align="left">van den Brink</td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td/>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
</tr>
<tr>
<td valign="top" align="left">Xu</td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td/>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td/>
<td/>
</tr>
<tr>
<td valign="top" align="left">Kuroki</td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
</tr>
<tr>
<td valign="top" align="left">Nishi</td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td/>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="t1fns1">&#x002A;</xref></td>
</tr>
</tbody>
</table>
<table-wrap-foot>
<fn id="t1fns1"><p>&#x002A;The study fulfilled the criteria.</p></fn>
</table-wrap-foot>
</table-wrap>
<sec id="S3.SS1">
<title>Patient characteristics</title>
<p>The overall mean patient age was 65.9 years and ranged from 53 to 72 years. 81.5% were male, 24.7% of the patients had a history of arterial hypertension and 19.9% had a history of diabetes mellitus type 2. The patient characteristics are summarized in <xref ref-type="table" rid="T2">Table 2</xref>.</p>
<table-wrap position="float" id="T2">
<label>TABLE 2</label>
<caption><p>Patient and study characteristics.</p></caption>
<table cellspacing="5" cellpadding="5" frame="box" rules="all">
<thead>
<tr>
<td valign="top" align="left" style="color:#ffffff;background-color: #7f8080;">First author</td>
<td valign="top" align="center" style="color:#ffffff;background-color: #7f8080;">Year</td>
<td valign="top" align="left" style="color:#ffffff;background-color: #7f8080;">Country</td>
<td valign="top" align="left" style="color:#ffffff;background-color: #7f8080;">Study design</td>
<td valign="top" align="center" style="color:#ffffff;background-color: #7f8080;">Patiens (n)</td>
<td valign="top" align="center" style="color:#ffffff;background-color: #7f8080;">ECMO (n)</td>
<td valign="top" align="center" style="color:#ffffff;background-color: #7f8080;">ECMO + IABP (n)</td>
<td valign="top" align="center" style="color:#ffffff;background-color: #7f8080;">Mean age</td>
<td valign="top" align="center" style="color:#ffffff;background-color: #7f8080;">Male</td>
<td valign="top" align="center" style="color:#ffffff;background-color: #7f8080;">AHT</td>
<td valign="top" align="center" style="color:#ffffff;background-color: #7f8080;">DM</td>
<td valign="top" align="center" style="color:#ffffff;background-color: #7f8080;">CAD</td>
<td valign="top" align="center" style="color:#ffffff;background-color: #7f8080;">Pre. stroke</td>
<td valign="top" align="center" style="color:#ffffff;background-color: #7f8080;">Pre. MI</td>
</tr>
</thead>
<tbody>
<tr>
<td valign="top" align="left">Aoyama et al. (<xref ref-type="bibr" rid="B21">21</xref>)</td>
<td valign="top" align="center">2014</td>
<td valign="top" align="left">Japan</td>
<td valign="top" align="left">Retrospective cohort</td>
<td valign="top" align="center">38</td>
<td valign="top" align="center">3</td>
<td valign="top" align="center">35</td>
<td valign="top" align="center">60</td>
<td valign="top" align="center">88</td>
<td valign="top" align="center">NC</td>
<td valign="top" align="center">NC</td>
<td valign="top" align="center">NC</td>
<td valign="top" align="center">NC</td>
<td valign="top" align="center">NC</td>
</tr>
<tr>
<td valign="top" align="left">Chung et al. (<xref ref-type="bibr" rid="B22">22</xref>)</td>
<td valign="top" align="center">2011</td>
<td valign="top" align="left">Korea</td>
<td valign="top" align="left">Retrospective cohort</td>
<td valign="top" align="center">20</td>
<td valign="top" align="center">6</td>
<td valign="top" align="center">14</td>
<td valign="top" align="center">61</td>
<td valign="top" align="center">70</td>
<td valign="top" align="center">45</td>
<td valign="top" align="center">35</td>
<td valign="top" align="center">NC</td>
<td valign="top" align="center">NC</td>
<td valign="top" align="center">NC</td>
</tr>
<tr>
<td valign="top" align="left">Kagawa et al. (<xref ref-type="bibr" rid="B25">25</xref>)</td>
<td valign="top" align="center">2012</td>
<td valign="top" align="left">Japan</td>
<td valign="top" align="left">Retrospective cohort</td>
<td valign="top" align="center">76</td>
<td valign="top" align="center">15</td>
<td valign="top" align="center">61</td>
<td valign="top" align="center">63</td>
<td valign="top" align="center">70</td>
<td valign="top" align="center">54</td>
<td valign="top" align="center">27</td>
<td valign="top" align="center">NC</td>
<td valign="top" align="center">NC</td>
<td valign="top" align="center">19</td>
</tr>
<tr>
<td valign="top" align="left">Muller et al. (<xref ref-type="bibr" rid="B26">26</xref>)</td>
<td valign="top" align="center">2016</td>
<td valign="top" align="left">France</td>
<td valign="top" align="left">Retrospective cohort</td>
<td valign="top" align="center">138</td>
<td valign="top" align="center">42</td>
<td valign="top" align="center">96</td>
<td valign="top" align="center">55</td>
<td valign="top" align="center">80</td>
<td valign="top" align="center">NC</td>
<td valign="top" align="center">NC</td>
<td valign="top" align="center">NC</td>
<td valign="top" align="center">NC</td>
<td valign="top" align="center">NC</td>
</tr>
<tr>
<td valign="top" align="left">Negi et al. (<xref ref-type="bibr" rid="B27">27</xref>)</td>
<td valign="top" align="center">2016</td>
<td valign="top" align="left">US</td>
<td valign="top" align="left">Retrospective cohort</td>
<td valign="top" align="center">15</td>
<td valign="top" align="center">6</td>
<td valign="top" align="center">9</td>
<td valign="top" align="center">57</td>
<td valign="top" align="center">60</td>
<td valign="top" align="center">NC</td>
<td valign="top" align="center">NC</td>
<td valign="top" align="center">NC</td>
<td valign="top" align="center">NC</td>
<td valign="top" align="center">NC</td>
</tr>
<tr>
<td valign="top" align="left">Overtchouk et al. (<xref ref-type="bibr" rid="B28">28</xref>)</td>
<td valign="top" align="center">2016</td>
<td valign="top" align="left">France</td>
<td valign="top" align="left">Retrospective cohort</td>
<td valign="top" align="center">106</td>
<td valign="top" align="center">43</td>
<td valign="top" align="center">63</td>
<td valign="top" align="center">53</td>
<td valign="top" align="center">84</td>
<td valign="top" align="center">39</td>
<td valign="top" align="center">21</td>
<td valign="top" align="center">23</td>
<td valign="top" align="center">NC</td>
<td valign="top" align="center">22</td>
</tr>
<tr>
<td valign="top" align="left">Park et al. (<xref ref-type="bibr" rid="B29">29</xref>)</td>
<td valign="top" align="center">2014</td>
<td valign="top" align="left">Korea</td>
<td valign="top" align="left">Retrospective cohort</td>
<td valign="top" align="center">96</td>
<td valign="top" align="center">55</td>
<td valign="top" align="center">41</td>
<td valign="top" align="center">65</td>
<td valign="top" align="center">76</td>
<td valign="top" align="center">23</td>
<td valign="top" align="center">31</td>
<td valign="top" align="center">19</td>
<td valign="top" align="center">NC</td>
<td valign="top" align="center">12</td>
</tr>
<tr>
<td valign="top" align="left">Sakamoto et al. (<xref ref-type="bibr" rid="B30">30</xref>)</td>
<td valign="top" align="center">2012</td>
<td valign="top" align="left">Japan</td>
<td valign="top" align="left">Retrospective cohort</td>
<td valign="top" align="center">98</td>
<td valign="top" align="center">4</td>
<td valign="top" align="center">94</td>
<td valign="top" align="center">72</td>
<td valign="top" align="center">66</td>
<td valign="top" align="center">45</td>
<td valign="top" align="center">35</td>
<td valign="top" align="center">NC</td>
<td valign="top" align="center">9</td>
<td valign="top" align="center">6</td>
</tr>
<tr>
<td valign="top" align="left">Van den Brink et al. (<xref ref-type="bibr" rid="B32">32</xref>)</td>
<td valign="top" align="center">2021</td>
<td valign="top" align="left">Netherland</td>
<td valign="top" align="left">Retrospective cohort</td>
<td valign="top" align="center">18</td>
<td valign="top" align="center">11</td>
<td valign="top" align="center">7</td>
<td valign="top" align="center">60</td>
<td valign="top" align="center">78</td>
<td valign="top" align="center">32</td>
<td valign="top" align="center">NC</td>
<td valign="top" align="center">17</td>
<td valign="top" align="center">NC</td>
<td valign="top" align="center">NC</td>
</tr>
<tr>
<td valign="top" align="left">Xu et al. (<xref ref-type="bibr" rid="B31">31</xref>)</td>
<td valign="top" align="center">2016</td>
<td valign="top" align="left">Australia</td>
<td valign="top" align="left">Retrospective cohort</td>
<td valign="top" align="center">16</td>
<td valign="top" align="center">11</td>
<td valign="top" align="center">5</td>
<td valign="top" align="center">62</td>
<td valign="top" align="center">62</td>
<td valign="top" align="center">NC</td>
<td valign="top" align="center">38</td>
<td valign="top" align="center">NC</td>
<td valign="top" align="center">NC</td>
<td valign="top" align="center">NC</td>
</tr>
<tr>
<td valign="top" align="left">Kuroki et al. (<xref ref-type="bibr" rid="B23">23</xref>)</td>
<td valign="top" align="center">2021</td>
<td valign="top" align="left">Japan</td>
<td valign="top" align="left">Retrospective cohort</td>
<td valign="top" align="center">627</td>
<td valign="top" align="center">89</td>
<td valign="top" align="center">538</td>
<td valign="top" align="center">65</td>
<td valign="top" align="center">84</td>
<td valign="top" align="center">NC</td>
<td valign="top" align="center">NC</td>
<td valign="top" align="center">NC</td>
<td valign="top" align="center">NC</td>
<td valign="top" align="center">NC</td>
</tr>
<tr>
<td valign="top" align="left">Nishi et al. (<xref ref-type="bibr" rid="B24">24</xref>)</td>
<td valign="top" align="center">2022</td>
<td valign="top" align="left">Japan</td>
<td valign="top" align="left">National registry</td>
<td valign="top" align="center">3,815</td>
<td valign="top" align="center">851</td>
<td valign="top" align="center">2,964</td>
<td valign="top" align="center">67</td>
<td valign="top" align="center">82</td>
<td valign="top" align="center">21</td>
<td valign="top" align="center">19</td>
<td valign="top" align="center">NC</td>
<td valign="top" align="center">NC</td>
<td valign="top" align="center">NC</td>
</tr>
</tbody>
</table>
<table-wrap-foot>
<fn><p>Vales are presented in percentages unless indicated otherwise. AHT, arterial hypertonus; CAD, coronary artery disease; DM, diabetes mellitus type 2; pre., previous.</p></fn>
</table-wrap-foot>
</table-wrap>
</sec>
<sec id="S3.SS2">
<title>Reasons for IABP treatment</title>
<p>Five studies reported the indications for additional IABP treatment (<xref ref-type="bibr" rid="B21">21</xref>, <xref ref-type="bibr" rid="B22">22</xref>, <xref ref-type="bibr" rid="B28">28</xref>, <xref ref-type="bibr" rid="B30">30</xref>, <xref ref-type="bibr" rid="B33">33</xref>). Two studies reported the decision for additional IABP treatment was made by the physician in charge (<xref ref-type="bibr" rid="B28">28</xref>, <xref ref-type="bibr" rid="B33">33</xref>), two studies reported that an IABP was routinely implanted in absence of any contra indication (<xref ref-type="bibr" rid="B21">21</xref>, <xref ref-type="bibr" rid="B30">30</xref>) and one study reported that an additional IABP was implanted in case the arterial pulse wave disappeared after using VA-ECMO support (<xref ref-type="bibr" rid="B22">22</xref>).</p>
</sec>
<sec id="S3.SS3">
<title>Mortality VA-ECMO + IAPB vs. VA-ECMO at 30-day/in-hospital</title>
<p>Four studies reported the 30-day/in-hospital mortality (<xref ref-type="bibr" rid="B23">23</xref>&#x2013;<xref ref-type="bibr" rid="B25">25</xref>, <xref ref-type="bibr" rid="B28">28</xref>) and eight studies the in-hospital mortality (<xref ref-type="bibr" rid="B21">21</xref>, <xref ref-type="bibr" rid="B22">22</xref>, <xref ref-type="bibr" rid="B26">26</xref>, <xref ref-type="bibr" rid="B30">30</xref>&#x2013;<xref ref-type="bibr" rid="B33">33</xref>). Overall mortality was 75.1% (<italic>n</italic> = 3802) and 85.6% (<italic>n</italic> = 973) in the VA-ECMO and 72% (<italic>n</italic> = 2829) in the VA-ECMO + IABP group. The in-hospital/30-day mortality was reported in all studies, the conducted meta-analysis showed that patients treated with VA-ECMO + IABP had a significantly lower odds ratio for mortality (OR 0.36, 95% CI 0.30&#x2013;0.44, <italic>P</italic> &#x2264; 0.001; <xref ref-type="fig" rid="F2">Figure 2A</xref>), with low heterogeneity (<italic>I</italic><sup>2</sup> = 11%). A performed funnel plot showed that the study by Muller et al. might be at risk for reporting bias (<xref ref-type="fig" rid="F3">Figure 3</xref>). A subgroup analysis was conducted in which the Japanese registry by Kuroki et al. was excluded to prohibit including patients multiple times. The overall 30-day/in-hospital mortality within the subgroup analysis including 1,248 patients (ECMO <italic>n</italic> = 285; ECMO + IABP 963) was 63.6% (<italic>n</italic> = 794), in the VA-ECMO 69.8% (<italic>n</italic> = 199) and in the VA-ECMO + IABP group 61.8% (<italic>n</italic> = 595) (<xref ref-type="fig" rid="F2">Figure 2B</xref>).</p>
<fig id="F2" position="float">
<label>FIGURE 2</label>
<caption><p>Forest plot on 30-day survival ECMO + IABP vs. ECMO. <bold>(A)</bold> All included studies. <bold>(B)</bold> Subgroup analysis excluding Nishi et al. from 2022. Individual studies and pooled analysis showing a significant decreased 30-day mortality for patients in cardiogenic shock due to acute myocardial infarction treated with ECMO + IABP compared to patients with ECMO only (<italic>p</italic> = 0.003). CI, confidence interval; OR, odds ratio.</p></caption>
<graphic mimetype="image" mime-subtype="tiff" xlink:href="fcvm-09-1104357-g002.tif"/>
</fig>
<fig id="F3" position="float">
<label>FIGURE 3</label>
<caption><p>Funnel plot.</p></caption>
<graphic mimetype="image" mime-subtype="tiff" xlink:href="fcvm-09-1104357-g003.tif"/>
</fig>
</sec>
<sec id="S3.SS4">
<title>Weaning from VA-ECMO + IAPB vs. VA-ECMO</title>
<p>Three studies reported on their successful VA-ECMO weaning rate, including 104 VA-ECMO and 118 VA-ECMO + IABP patients with a success rate of 30.8 and 55.1% (<xref ref-type="bibr" rid="B22">22</xref>, <xref ref-type="bibr" rid="B28">28</xref>, <xref ref-type="bibr" rid="B33">33</xref>). Successful weaning was not specifically defined in any of the studies. The conducted meta-analysis of successful VA-ECMO weaning rate showed that patients treated with IABP had a significantly higher odds ratio for successful weaning (OR 0.29, 95% CI 0.16&#x2013;0.53, <italic>P</italic> &#x003C; 0.001; <xref ref-type="fig" rid="F4">Figure 4</xref>), with low heterogeneity (<italic>I</italic><sup>2</sup> = 0%).</p>
<fig id="F4" position="float">
<label>FIGURE 4</label>
<caption><p>Forest plot on weaning success of ECMO + IABP vs. ECMO. Individual studies and pooled analysis showing a significant increased successful ECMO weaning for patients in cardiogenic shock due to acute myocardial infarction treated with ECMO + IABP compared to patients with ECMO only (<italic>p</italic> &#x003C; 0.001). CI, confidence interval; OR, odds ratio.</p></caption>
<graphic mimetype="image" mime-subtype="tiff" xlink:href="fcvm-09-1104357-g004.tif"/>
</fig>
</sec>
<sec id="S3.SS5">
<title>Vascular complications VA-ECMO + IAPB vs. VA-ECMO</title>
<p>Two studies reported on their vascular complication rate, including 66 VA-ECMO and 48 VA-ECMO + IABP patients with a vascular complication rate of 22.7 and 25% (<xref ref-type="bibr" rid="B32">32</xref>, <xref ref-type="bibr" rid="B33">33</xref>). The conducted meta-analysis of the vascular complication rate showed that ECMO only did not significantly lower the risk for vascular access complications (OR 0.85, 95% CI 0.35&#x2013;2.08, <italic>P</italic> = 0.72; <xref ref-type="fig" rid="F5">Figure 5</xref>), with low heterogeneity (<italic>I</italic><sup>2</sup> = 0%).</p>
<fig id="F5" position="float">
<label>FIGURE 5</label>
<caption><p>Forest plot on vascular complications of ECMO + IABP vs. ECMO. Individual studies and pooled analysis showing no significant differences in the incidence of vascular complications for patients in cardiogenic shock due to acute myocardial infarction treated with ECMO + IABP compared to patients with ECMO only (<italic>p</italic> &#x003C; 0.001). CI, confidence interval; OR, odds ratio.</p></caption>
<graphic mimetype="image" mime-subtype="tiff" xlink:href="fcvm-09-1104357-g005.tif"/>
</fig>
</sec>
</sec>
<sec id="S4" sec-type="discussion">
<title>Discussion</title>
<p>In patients with CS due to AMI combination of VA-ECMO + IABP was associated with a lower 30-day/in-hospital mortality rate compared to VA-ECMO alone while access site complications were comparable in both groups.</p>
<p>To date, treatment of patients with CS caused by AMI with VA-ECMO is restricted to specialized cardiac arrest centers, and patient selection or indication is not standardized. However, it is uncertain if patients in CS benefit from VA-ECMO compared to optimal medical treatment. We await randomized data of the ECLS shock trials providing data to answer this question. The recently presented ECMO-CS trial showed no benefit of early VA-ECMO implantation without a venting strategy in 117 randomized patients in CS (<xref ref-type="bibr" rid="B34">34</xref>), with a crossover rate of 39%. A meta-analysis of retrospective studies showed that VA-ECMO improved 30-day mortality by 13% for patients in CS (<xref ref-type="bibr" rid="B35">35</xref>). The randomized ANCHOR trial enrolled its first patient in October 2021 comparing optimal medical treatment with VA-ECMO + IABP in CS due to AMI patients (<xref ref-type="bibr" rid="B36">36</xref>).</p>
<p>In this study we conducted the first meta-analysis in the subgroup of CS AMI patients comparing VA-ECMO + IABP vs. VA-ECMO alone. In 2018, a similar meta-analysis was performed in general CS patients and investigated a subgroup of AMI patients (<xref ref-type="bibr" rid="B37">37</xref>) in contrast to our trial, this study included all forms of cardiogenic shock. Vallabhajosyula et al. found no impact on survival of a concomitant use of IABP and VA-ECMO in the total cohort. Only the subgroup of AMI patients, not further defined, displayed lower mortality rates in the VA-ECMO + IABP group compared to VA-ECMO alone (OR 0.56). A similar meta-analysis focusing on left ventricular unloading during extracorporeal membrane oxygenation published by Russo et al. in 2019 also showed lower mortality in patients receiving ECMO + IABP in CS compared to ECMO alone. However, they performed no analysis on patients in CS due to AMI (<xref ref-type="bibr" rid="B38">38</xref>). In our meta-analysis, conducted with AMI patients only, we were able to add four more trials with a total of 248 patients. Regarding mortality rates, these results were confirmed by our study as VA-ECMO + IABP was associated with lower 30-day/in-hospital mortality rates and comparable effective size (OR 0.36).</p>
<p>Our meta-analysis also showed that VA-ECMO weaning success was superior in patients receiving an additional IABP. The benefit might be a general effect of improved myocardial recovery; additionally, IABP could facilitate a smoother transition between the lowest ECMO to zero flow. Especially in myocardial infarction it might be relevant to make use of a venting strategy as early as possible to counteract an otherwise increased oxygen expenditure of the failing cardiomyocytes (<xref ref-type="bibr" rid="B39">39</xref>).</p>
<p>For both IABP and VA-ECMO, patients&#x2019; vascular complications are common and might contribute to the overall prognosis. Nearly a third of VA-ECMO and 15% of IABP patients suffer a vascular complication (<xref ref-type="bibr" rid="B40">40</xref>, <xref ref-type="bibr" rid="B41">41</xref>). As vascular complications significantly impact mortality in VA-ECMO patients, any additional complications of arterial canulation for IABP would have to be taken very seriously. In patients receiving an VA-ECMO + transvalvular microaxial flow pump, an increase in severe bleeding complications and access site related ischemia was reported (<xref ref-type="bibr" rid="B42">42</xref>). Within our meta-analysis, we found no differences regarding access site complications, but only two studies reported data which could be included. This suggests a form of reporting bias. Thus, it is not possible to definitively answer this question based on the included sample size. However, in the IABP Shock II trial there were no differences between the IABP and the optimal medical treatment groups regarding bleeding complications and peripheral ischemia requiring intervention (<xref ref-type="bibr" rid="B43">43</xref>). An advantage of IABP compared to a transvalvular microaxial flow pump as a venting device might thus be a lower vascular complication profile due to its smaller access size.</p>
<p>It remains unclear which &#x201C;venting&#x201D; strategy might be the best in this special setting. VA-ECMO + transvalvular microaxial flow pump (so called &#x201C;ECMELLA&#x201D;) was investigated in a retrospective multicenter study with 686 CS patients and was associated with a lower mortality rate after 30 days compared to VA-ECMO therapy alone (<xref ref-type="bibr" rid="B44">44</xref>). In the vast majority of patients, CS was caused by AMI and only about one third was non-ischemic. However, the favorable effect of VA-ECMO + transvalvular microaxial flow pump was consistent in both groups. One further propensity-matched retrospective cohort study reported reduced in-hospital mortality and increased VA-ECMO weaning success in patients with VA-ECMO + transvalvular microaxial flow pump compared to VA-ECMO alone (<xref ref-type="bibr" rid="B45">45</xref>). Even though, we do not have prospective or even randomized data supporting the theories on LV venting effects of an additional IABP or transvalvular microaxial flow pump, hemodynamic and experimental studies have proven the underlying theories of LV afterload reduction and therefore the LV decompression (<xref ref-type="bibr" rid="B46">46</xref>, <xref ref-type="bibr" rid="B47">47</xref>). At this point it is hard to tell which venting device may be more beneficial in patients with CS. The effectiveness of a transvalvular microaxial flow pump is independent from heart rhythm, rate, and underlying cardiac index. These attributes might contribute to more efficient and sustainable LV venting. On the other hand, an advantage of IABP compared to a transvalvular microaxial flow pump might be a lower bleeding and vascular complication profile.</p>
<sec id="S4.SS1">
<title>Limitations</title>
<p>The most relevant limitation of this study is the lack of any randomized comparison between VA-ECMO and VA-ECMO + IABP. Furthermore, all the included data was collected retrospectively. Most studies do not focus on the comparison between VA-ECMO and VA-ECMO + IABP, therefore the reason why an additional IABP is used is not clear in most studies and selection bias for the use of an IABP might be present in most studies. In addition to the nature of a review, the original studies were thus designed heterogeneously, with potential differences in baseline data and in risk profiles. A further limitation of this study is the small number of patients included in the studies. We also included studies which were published over a considerable period of time, dating back to the last decade. In the meantime, both devices and sheaths used have undergone constant iterative changes, which might have influenced the results.</p>
</sec>
</sec>
<sec id="S5" sec-type="conclusion">
<title>Conclusion</title>
<p>In this meta-analysis, combination therapy of VA-ECMO + IABP was superior to VA-ECMO only in patients with CS due to AMI. Randomized and structured data is needed to evaluate the value of VA-ECMO + IABP in patients with CS due to AMI.</p>
</sec>
<sec id="S6" sec-type="data-availability">
<title>Data availability statement</title>
<p>The original contributions presented in this study are included in the article/supplementary material, further inquiries can be directed to the corresponding author.</p>
</sec>
<sec id="S7" sec-type="ethics-statement">
<title>Ethics statement</title>
<p>Ethical review and approval was not required for the study on human participants in accordance with the local legislation and institutional requirements. Written informed consent for participation was not required for this study in accordance with the national legislation and the institutional requirements.</p>
</sec>
<sec id="S8" sec-type="author-contributions">
<title>Author contributions</title>
<p>TT and MM: conceptualization, data curation, formal analysis, investigation, methodology, project administration, validation, visualization, writing&#x2014;original draft, and writing&#x2014;review and editing. SM-M, SH, SBr, SN, CA, and SBa: investigation, project administration, resources, supervision, validation, and writing&#x2014;review and editing. CA and SL: data curation, investigation, project administration, resources, supervision, validation, visualization, writing&#x2014;original draft, and writing&#x2014;review and editing. All authors contributed to the article and approved the submitted version.</p>
</sec>
</body>
<back>
<ack><p>We thank Thomas Tichelb&#x00E4;cker (Princeton University, United States) for helpful comments regarding language and grammar.</p>
</ack>
<sec id="S9" sec-type="COI-statement">
<title>Conflict of interest</title>
<p>The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.</p>
</sec>
<sec id="S10" sec-type="disclaimer">
<title>Publisher&#x2019;s note</title>
<p>All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.</p>
</sec>
<ref-list>
<title>References</title>
<ref id="B1"><label>1.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Samsky</surname> <given-names>M</given-names></name> <name><surname>Morrow</surname> <given-names>D</given-names></name> <name><surname>Proudfoot</surname> <given-names>A</given-names></name> <name><surname>Hochman</surname> <given-names>J</given-names></name> <name><surname>Thiele</surname> <given-names>H</given-names></name> <name><surname>Rao</surname> <given-names>SV</given-names></name></person-group>. <article-title>Cardiogenic shock after acute myocardial infarction: a review.</article-title> <source><italic>JAMA.</italic></source> (<year>2021</year>) <volume>326</volume>:<fpage>1840</fpage>&#x2013;<lpage>50</lpage>. <pub-id pub-id-type="doi">10.1001/jama.2021.18323</pub-id> <pub-id pub-id-type="pmid">34751704</pub-id></citation></ref>
<ref id="B2"><label>2.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Lang</surname> <given-names>C</given-names></name> <name><surname>Kaier</surname> <given-names>K</given-names></name> <name><surname>Zotzmann</surname> <given-names>V</given-names></name> <name><surname>Stachon</surname> <given-names>P</given-names></name> <name><surname>Pottgiesser</surname> <given-names>T</given-names></name> <name><surname>von zur Muehlen</surname> <given-names>C</given-names></name><etal/></person-group> <article-title>Cardiogenic shock: incidence, survival and mechanical circulatory support usage 2007&#x2013;2017-insights from a national registry.</article-title> <source><italic>Clin Res Cardiol.</italic></source> (<year>2021</year>) <volume>110</volume>:<fpage>1421</fpage>&#x2013;<lpage>30</lpage>. <pub-id pub-id-type="doi">10.1007/s00392-020-01781-z</pub-id> <pub-id pub-id-type="pmid">33258007</pub-id></citation></ref>
<ref id="B3"><label>3.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Helgestad</surname> <given-names>O</given-names></name> <name><surname>Josiassen</surname> <given-names>J</given-names></name> <name><surname>Hassager</surname> <given-names>C</given-names></name> <name><surname>Jensen</surname> <given-names>L</given-names></name> <name><surname>Holmvang</surname> <given-names>L</given-names></name> <name><surname>S&#x00F8;rensen</surname> <given-names>A</given-names></name><etal/></person-group> <article-title>Temporal trends in incidence and patient characteristics in cardiogenic shock following acute myocardial infarction from 2010 to 2017: a Danish cohort study.</article-title> <source><italic>Eur J Heart Fail.</italic></source> (<year>2019</year>) <volume>21</volume>:<fpage>1370</fpage>&#x2013;<lpage>8</lpage>. <pub-id pub-id-type="doi">10.1002/ejhf.1566</pub-id> <pub-id pub-id-type="pmid">31339222</pub-id></citation></ref>
<ref id="B4"><label>4.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Thiele</surname> <given-names>H</given-names></name> <name><surname>Akin</surname> <given-names>I</given-names></name> <name><surname>Sandri</surname> <given-names>M</given-names></name> <name><surname>Fuernau</surname> <given-names>G</given-names></name> <name><surname>de Waha</surname> <given-names>S</given-names></name> <name><surname>Meyer-Saraei</surname> <given-names>R</given-names></name><etal/></person-group> <article-title>PCI strategies in patients with acute myocardial infarction and cardiogenic shock.</article-title> <source><italic>N Engl J Med.</italic></source> (<year>2017</year>) <volume>377</volume>:<fpage>2419</fpage>&#x2013;<lpage>32</lpage>. <pub-id pub-id-type="doi">10.1056/NEJMoa1710261</pub-id> <pub-id pub-id-type="pmid">29083953</pub-id></citation></ref>
<ref id="B5"><label>5.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Eckman</surname> <given-names>P</given-names></name> <name><surname>Katz</surname> <given-names>J</given-names></name> <name><surname>El Banayosy</surname> <given-names>A</given-names></name> <name><surname>Bohula</surname> <given-names>E</given-names></name> <name><surname>Sun</surname> <given-names>B</given-names></name> <name><surname>van Diepen</surname> <given-names>S</given-names></name></person-group>. <article-title>Veno-arterial extracorporeal membrane oxygenation for cardiogenic shock.</article-title> <source><italic>Circulation.</italic></source> (<year>2019</year>) <volume>140</volume>:<fpage>2019</fpage>&#x2013;<lpage>37</lpage>. <pub-id pub-id-type="doi">10.1161/CIRCULATIONAHA.119.034512</pub-id> <pub-id pub-id-type="pmid">31815538</pub-id></citation></ref>
<ref id="B6"><label>6.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>McDonagh</surname> <given-names>T</given-names></name> <name><surname>Metra</surname> <given-names>M</given-names></name> <name><surname>Adamo</surname> <given-names>M</given-names></name> <name><surname>Gardner</surname> <given-names>R</given-names></name> <name><surname>Baumbach</surname> <given-names>A</given-names></name> <name><surname>B&#x00F6;hm</surname> <given-names>M</given-names></name><etal/></person-group> <article-title>2021 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure: developed by the task force for the diagnosis and treatment of acute and chronic heart failure of the European society of cardiology (ESC) With the special contribution.</article-title> <source><italic>Eur Heart J.</italic></source> (<year>2021</year>) <volume>42</volume>:<fpage>3599</fpage>&#x2013;<lpage>726</lpage>.</citation></ref>
<ref id="B7"><label>7.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Thiagarajan</surname> <given-names>R</given-names></name> <name><surname>Barbaro</surname> <given-names>R</given-names></name> <name><surname>Rycus</surname> <given-names>P</given-names></name> <name><surname>Mcmullan</surname> <given-names>D</given-names></name> <name><surname>Conrad</surname> <given-names>S</given-names></name> <name><surname>Fortenberry</surname> <given-names>J</given-names></name><etal/></person-group> <article-title>Extracorporeal life support organization registry international report 2016.</article-title> <source><italic>ASAIO J.</italic></source> (<year>2017</year>) <volume>63</volume>:<fpage>60</fpage>&#x2013;<lpage>7</lpage>. <pub-id pub-id-type="doi">10.1097/MAT.0000000000000475</pub-id> <pub-id pub-id-type="pmid">27984321</pub-id></citation></ref>
<ref id="B8"><label>8.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Burkhoff</surname> <given-names>D</given-names></name> <name><surname>Sayer</surname> <given-names>G</given-names></name> <name><surname>Doshi</surname> <given-names>D</given-names></name> <name><surname>Uriel</surname> <given-names>N</given-names></name></person-group>. <article-title>Hemodynamics of mechanical circulatory support.</article-title> <source><italic>J Am Coll Cardiol.</italic></source> (<year>2015</year>) <volume>66</volume>:<fpage>2663</fpage>&#x2013;<lpage>74</lpage>. <pub-id pub-id-type="doi">10.1016/j.jacc.2015.10.017</pub-id> <pub-id pub-id-type="pmid">26670067</pub-id></citation></ref>
<ref id="B9"><label>9.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Cevasco</surname> <given-names>M</given-names></name> <name><surname>Takayama</surname> <given-names>H</given-names></name> <name><surname>Ando</surname> <given-names>M</given-names></name> <name><surname>Garan</surname> <given-names>A</given-names></name> <name><surname>Naka</surname> <given-names>Y</given-names></name> <name><surname>Takeda</surname> <given-names>K</given-names></name></person-group>. <article-title>Left ventricular distension and venting strategies for patients on venoarterial extracorporeal membrane oxygenation.</article-title> <source><italic>J Thorac Dis.</italic></source> (<year>2019</year>) <volume>11</volume>:<fpage>1676</fpage>&#x2013;<lpage>83</lpage>. <pub-id pub-id-type="doi">10.21037/jtd.2019.03.29</pub-id> <pub-id pub-id-type="pmid">31179113</pub-id></citation></ref>
<ref id="B10"><label>10.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Ibrahim</surname> <given-names>M</given-names></name> <name><surname>Bermudez</surname> <given-names>C.</given-names></name></person-group> <source><italic>Impella CP With VA ECMO for Cardiogenic Shock (REVERSE). Identifier NCT03431467.</italic></source> (<year>2018</year>). Available online at: <ext-link ext-link-type="uri" xlink:href="http://clinicaltrials.gov/ct2/show/NCT03431467">clinicaltrials.gov/ct2/show/NCT03431467</ext-link> (<comment>accessed February 2018</comment>).</citation></ref>
<ref id="B11"><label>11.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Moher</surname> <given-names>D</given-names></name> <name><surname>Liberati</surname> <given-names>A</given-names></name> <name><surname>Tetzlaff</surname> <given-names>J</given-names></name> <name><surname>Altman</surname> <given-names>D</given-names></name> <name><surname>Altman</surname> <given-names>D</given-names></name> <name><surname>Antes</surname> <given-names>G</given-names></name><etal/></person-group> <article-title>Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement.</article-title> <source><italic>PLoS Med.</italic></source> (<year>2009</year>) <volume>6</volume>:<issue>e1000097</issue>. <pub-id pub-id-type="doi">10.1371/journal.pmed.1000097</pub-id> <pub-id pub-id-type="pmid">19621072</pub-id></citation></ref>
<ref id="B12"><label>12.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Wells</surname> <given-names>G</given-names></name> <name><surname>Shea</surname> <given-names>B</given-names></name> <name><surname>O&#x2019;Connel</surname> <given-names>D.</given-names></name></person-group> <source><italic>The Newcastle-Ottawa Scale (NOS) for Assessing the Quality of Nonrandomised Studies in Meta-Analyses.</italic></source> <publisher-loc>Ottawa, ON</publisher-loc>: <publisher-name>Ottawa Hospital Research Institute</publisher-name> (<year>2021</year>).</citation></ref>
<ref id="B13"><label>13.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Aso</surname> <given-names>S</given-names></name> <name><surname>Matsui</surname> <given-names>H</given-names></name> <name><surname>Fushimi</surname> <given-names>K</given-names></name> <name><surname>Yasunaga</surname> <given-names>H</given-names></name></person-group>. <article-title>The effect of intraaortic balloon pumping under venoarterial extracorporeal membrane oxygenation on mortality of cardiogenic patients: an analysis using a nationwide inpatient database.</article-title> <source><italic>Crit Care Med.</italic></source> (<year>2016</year>) <volume>44</volume>:<fpage>1974</fpage>&#x2013;<lpage>9</lpage>. <pub-id pub-id-type="doi">10.1097/CCM.0000000000001828</pub-id> <pub-id pub-id-type="pmid">27322361</pub-id></citation></ref>
<ref id="B14"><label>14.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Chen</surname> <given-names>J</given-names></name> <name><surname>Ko</surname> <given-names>W</given-names></name> <name><surname>Yu</surname> <given-names>H</given-names></name> <name><surname>Lai</surname> <given-names>L</given-names></name> <name><surname>Huang</surname> <given-names>S</given-names></name> <name><surname>Chi</surname> <given-names>N</given-names></name><etal/></person-group> <article-title>Analysis of the outcome for patients experiencing myocardial infarction and cardiopulmonary resuscitation refractory to conventional therapies necessitating extracorporeal life support rescue.</article-title> <source><italic>Crit Care Med.</italic></source> (<year>2006</year>) <volume>34</volume>:<fpage>950</fpage>&#x2013;<lpage>7</lpage>. <pub-id pub-id-type="doi">10.1097/01.CCM.0000206103.35460.1F</pub-id> <pub-id pub-id-type="pmid">16484889</pub-id></citation></ref>
<ref id="B15"><label>15.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Lin</surname> <given-names>L</given-names></name> <name><surname>Liao</surname> <given-names>C</given-names></name> <name><surname>Wang</surname> <given-names>C</given-names></name> <name><surname>Chi</surname> <given-names>N</given-names></name> <name><surname>Yu</surname> <given-names>H</given-names></name> <name><surname>Chou</surname> <given-names>N</given-names></name><etal/></person-group> <article-title>Effects of additional intra-aortic balloon counter-pulsation therapy to cardiogenic shock patients supported by extra-corporeal membranous oxygenation.</article-title> <source><italic>Sci Rep.</italic></source> (<year>2016</year>) <volume>6</volume>:<issue>23838</issue>. <pub-id pub-id-type="doi">10.1038/srep23838</pub-id> <pub-id pub-id-type="pmid">27032984</pub-id></citation></ref>
<ref id="B16"><label>16.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Kuroki</surname> <given-names>N</given-names></name> <name><surname>Nagao</surname> <given-names>K</given-names></name> <name><surname>Takayama</surname> <given-names>T</given-names></name> <name><surname>Hosokawa</surname> <given-names>Y</given-names></name> <name><surname>Tachibana</surname> <given-names>E</given-names></name> <name><surname>Ashida</surname> <given-names>T</given-names></name><etal/></person-group> <article-title>2994Impact of extracorporeal membrane oxygenation (ECMO) and intra-aortic balloon pump (IABP) for cardiac arrest.</article-title> <source><italic>Eur Heart J.</italic></source> (<year>2018</year>) <volume>39</volume>(<issue>Suppl. 1):ehy563.2994</issue>. <pub-id pub-id-type="doi">10.1093/eurheartj/ehy563.2994</pub-id></citation></ref>
<ref id="B17"><label>17.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Tsao</surname> <given-names>N</given-names></name> <name><surname>Shih</surname> <given-names>C</given-names></name> <name><surname>Yeh</surname> <given-names>J</given-names></name> <name><surname>Kao</surname> <given-names>Y</given-names></name> <name><surname>Hsieh</surname> <given-names>M</given-names></name> <name><surname>Ou</surname> <given-names>K</given-names></name><etal/></person-group> <article-title>Extracorporeal membrane oxygenation-assisted primary percutaneous coronary intervention may improve survival of patients with acute myocardial infarction complicated by profound cardiogenic shock.</article-title> <source><italic>J Crit Care.</italic></source> (<year>2012</year>) <volume>27</volume>:<fpage>530.e1</fpage>&#x2013;<lpage>11</lpage>. <pub-id pub-id-type="doi">10.1016/j.jcrc.2012.02.012</pub-id> <pub-id pub-id-type="pmid">22591567</pub-id></citation></ref>
<ref id="B18"><label>18.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Grandin</surname> <given-names>E</given-names></name> <name><surname>Nunez</surname> <given-names>J</given-names></name> <name><surname>Willar</surname> <given-names>B</given-names></name> <name><surname>Kennedy</surname> <given-names>K</given-names></name> <name><surname>Rycus</surname> <given-names>P</given-names></name> <name><surname>Tonna</surname> <given-names>J</given-names></name><etal/></person-group> <article-title>Mechanical left ventricular unloading in patients undergoing venoarterial extracorporeal membrane oxygenation.</article-title> <source><italic>J Am Coll Cardiol.</italic></source> (<year>2022</year>) <volume>79</volume>:<fpage>1239</fpage>&#x2013;<lpage>50</lpage>. <pub-id pub-id-type="doi">10.1016/j.jacc.2022.01.032</pub-id> <pub-id pub-id-type="pmid">35361346</pub-id></citation></ref>
<ref id="B19"><label>19.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Briasoulis</surname> <given-names>A</given-names></name> <name><surname>Kampaktsis</surname> <given-names>P</given-names></name> <name><surname>Emfietzoglou</surname> <given-names>M</given-names></name> <name><surname>Kuno</surname> <given-names>T</given-names></name> <name><surname>Van den Eynde</surname> <given-names>J</given-names></name> <name><surname>Ntalianis</surname> <given-names>A</given-names></name><etal/></person-group> <article-title>Temporary mechanical circulatory support in cardiogenic shock due to ST-elevation myocardial infarction: analysis of the national readmissions database.</article-title> <source><italic>Angiology.</italic></source> (<year>2022</year>) <volume>74</volume>:<fpage>31</fpage>&#x2013;<lpage>8</lpage>. <pub-id pub-id-type="doi">10.1177/00033197221091641</pub-id> <pub-id pub-id-type="pmid">35440216</pub-id></citation></ref>
<ref id="B20"><label>20.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Kida</surname> <given-names>H</given-names></name> <name><surname>Sotomi</surname> <given-names>Y</given-names></name> <name><surname>Hikoso</surname> <given-names>S</given-names></name> <name><surname>Nakatani</surname> <given-names>D</given-names></name> <name><surname>Mizuno</surname> <given-names>H</given-names></name> <name><surname>Suna</surname> <given-names>S</given-names></name><etal/></person-group> <article-title>Prognostic significance of intra-aortic balloon pumping support in patients with acute myocardial infarction and veno-arterial extracorporeal membrane oxygenation therapy.</article-title> <source><italic>J Cardiol.</italic></source> (<year>2022</year>) <volume>79</volume>:<fpage>179</fpage>&#x2013;<lpage>85</lpage>. <pub-id pub-id-type="doi">10.1016/j.jjcc.2021.10.011</pub-id> <pub-id pub-id-type="pmid">34750027</pub-id></citation></ref>
<ref id="B21"><label>21.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Aoyama</surname> <given-names>N</given-names></name> <name><surname>Imai</surname> <given-names>H</given-names></name> <name><surname>Kurosawa</surname> <given-names>T</given-names></name> <name><surname>Fukuda</surname> <given-names>N</given-names></name> <name><surname>Moriguchi</surname> <given-names>M</given-names></name> <name><surname>Nishinari</surname> <given-names>M</given-names></name><etal/></person-group> <article-title>Therapeutic strategy using extracorporeal life support, including appropriate indication, management, limitation and timing of switch to ventricular assist device in patients with acute myocardial infarction.</article-title> <source><italic>J Artif.</italic></source> (<year>2014</year>) <volume>17</volume>:<fpage>33</fpage>&#x2013;<lpage>41</lpage>. <pub-id pub-id-type="doi">10.1007/s10047-013-0735-z</pub-id> <pub-id pub-id-type="pmid">24162152</pub-id></citation></ref>
<ref id="B22"><label>22.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Chung</surname> <given-names>E</given-names></name> <name><surname>Lim</surname> <given-names>C</given-names></name> <name><surname>Lee</surname> <given-names>H</given-names></name> <name><surname>Choi</surname> <given-names>J</given-names></name> <name><surname>Lee</surname> <given-names>J</given-names></name> <name><surname>Park</surname> <given-names>K</given-names></name></person-group>. <article-title>Results of extracorporeal membrane oxygenation (ECMO) support before coronary reperfusion in cardiogenic shock with acute myocardial infarction.</article-title> <source><italic>Korean J Thorac Cardiovasc Surg.</italic></source> (<year>2011</year>) <volume>44</volume>:<fpage>273</fpage>&#x2013;<lpage>8</lpage>. <pub-id pub-id-type="doi">10.5090/kjtcs.2011.44.4.273</pub-id> <pub-id pub-id-type="pmid">22263168</pub-id></citation></ref>
<ref id="B23"><label>23.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Kuroki</surname> <given-names>N</given-names></name> <name><surname>Nagao</surname> <given-names>K</given-names></name> <name><surname>Otsuka</surname> <given-names>T</given-names></name> <name><surname>Kuwabara</surname> <given-names>M</given-names></name> <name><surname>Nakata</surname> <given-names>J</given-names></name> <name><surname>Takayama</surname> <given-names>T</given-names></name><etal/></person-group> <article-title>Combined use of venoarterial extracorporeal membrane oxygenation and intra-aortic balloon pump after cardiac arrest.</article-title> <source><italic>Resuscitation.</italic></source> (<year>2021</year>) <volume>167</volume>:<fpage>345</fpage>&#x2013;<lpage>54</lpage>. <pub-id pub-id-type="doi">10.1016/j.resuscitation.2021.07.019</pub-id> <pub-id pub-id-type="pmid">34314778</pub-id></citation></ref>
<ref id="B24"><label>24.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Nishi</surname> <given-names>T</given-names></name> <name><surname>Ishii</surname> <given-names>M</given-names></name> <name><surname>Tsujita</surname> <given-names>K</given-names></name> <name><surname>Okamoto</surname> <given-names>H</given-names></name> <name><surname>Koto</surname> <given-names>S</given-names></name> <name><surname>Nakai</surname> <given-names>M</given-names></name><etal/></person-group> <article-title>Outcomes of venoarterial extracorporeal membrane oxygenation plus intra-aortic balloon pumping for treatment of acute myocardial infarction complicated by cardiogenic shock.</article-title> <source><italic>J Am Heart Assoc.</italic></source> (<year>2022</year>) <volume>11</volume>:<issue>e023713</issue>. <pub-id pub-id-type="doi">10.1161/JAHA.121.023713</pub-id> <pub-id pub-id-type="pmid">35377180</pub-id></citation></ref>
<ref id="B25"><label>25.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Kagawa</surname> <given-names>E</given-names></name> <name><surname>Dote</surname> <given-names>K</given-names></name> <name><surname>Kato</surname> <given-names>M</given-names></name> <name><surname>Sasaki</surname> <given-names>S</given-names></name> <name><surname>Nakano</surname> <given-names>Y</given-names></name> <name><surname>Kajikawa</surname> <given-names>M</given-names></name><etal/></person-group> <article-title>Should we emergently revascularize occluded coronaries for cardiac arrest?</article-title> <source><italic>Circulation.</italic></source> (<year>2012</year>) <volume>126</volume>:<fpage>1605</fpage>&#x2013;<lpage>13</lpage>. <pub-id pub-id-type="doi">10.1161/CIRCULATIONAHA.111.067538</pub-id> <pub-id pub-id-type="pmid">22899771</pub-id></citation></ref>
<ref id="B26"><label>26.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Muller</surname> <given-names>G</given-names></name> <name><surname>Flecher</surname> <given-names>E</given-names></name> <name><surname>Lebreton</surname> <given-names>G</given-names></name> <name><surname>Luyt</surname> <given-names>C</given-names></name> <name><surname>Trouillet</surname> <given-names>J</given-names></name> <name><surname>Br&#x00E9;chot</surname> <given-names>N</given-names></name><etal/></person-group> <article-title>The ENCOURAGE mortality risk score and analysis of long-term outcomes after VA-ECMO for acute myocardial infarction with cardiogenic shock.</article-title> <source><italic>Intensive Care Med.</italic></source> (<year>2016</year>) <volume>42</volume>:<fpage>370</fpage>&#x2013;<lpage>8</lpage>. <pub-id pub-id-type="doi">10.1007/s00134-016-4223-9</pub-id> <pub-id pub-id-type="pmid">26825953</pub-id></citation></ref>
<ref id="B27"><label>27.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Negi</surname> <given-names>S</given-names></name> <name><surname>Sokolovic</surname> <given-names>M</given-names></name> <name><surname>Koifman</surname> <given-names>E</given-names></name> <name><surname>Kiramijyan</surname> <given-names>S</given-names></name> <name><surname>Torguson</surname> <given-names>R</given-names></name> <name><surname>Lindsay</surname> <given-names>J</given-names></name><etal/></person-group> <article-title>Contemporary use of Veno-arterial extracorporeal membrane oxygenation for refractory cardiogenic shock in acute coronary syndrome.</article-title> <source><italic>J Invasive Cardiol.</italic></source> (<year>2016</year>) <volume>28</volume>:<fpage>52</fpage>&#x2013;<lpage>7</lpage>.</citation></ref>
<ref id="B28"><label>28.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Overtchouk</surname> <given-names>P</given-names></name> <name><surname>Pascal</surname> <given-names>J</given-names></name> <name><surname>Lebreton</surname> <given-names>G</given-names></name> <name><surname>Hulot</surname> <given-names>J</given-names></name> <name><surname>Luyt</surname> <given-names>C</given-names></name> <name><surname>Combes</surname> <given-names>A</given-names></name><etal/></person-group> <article-title>Outcome after revascularisation of acute myocardial infarction with cardiogenic shock on extracorporeal life support.</article-title> <source><italic>EuroIntervention.</italic></source> (<year>2018</year>) <volume>13</volume>:<fpage>e2160</fpage>&#x2013;<lpage>8</lpage>. <pub-id pub-id-type="doi">10.4244/EIJ-D-17-01014</pub-id> <pub-id pub-id-type="pmid">29400656</pub-id></citation></ref>
<ref id="B29"><label>29.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Park</surname> <given-names>G</given-names></name> <name><surname>Song</surname> <given-names>K</given-names></name> <name><surname>Do Shin</surname> <given-names>S</given-names></name> <name><surname>Lee</surname> <given-names>K</given-names></name> <name><surname>Ahn</surname> <given-names>K</given-names></name> <name><surname>Lee</surname> <given-names>E</given-names></name><etal/></person-group> <article-title>Timely bystander CPR improves outcomes despite longer EMS times.</article-title> <source><italic>Am J Emerg Med.</italic></source> (<year>2017</year>) <volume>35</volume>:<fpage>1049</fpage>&#x2013;<lpage>55</lpage>. <pub-id pub-id-type="pmid">28237384</pub-id></citation></ref>
<ref id="B30"><label>30.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Sakamoto</surname> <given-names>S</given-names></name> <name><surname>Taniguchi</surname> <given-names>N</given-names></name> <name><surname>Nakajima</surname> <given-names>S</given-names></name> <name><surname>Takahashi</surname> <given-names>A</given-names></name></person-group>. <article-title>Extracorporeal life support for cardiogenic shock or cardiac arrest due to acute coronary syndrome.</article-title> <source><italic>Ann Thorac Surg.</italic></source> (<year>2012</year>) <volume>94</volume>:<fpage>1</fpage>&#x2013;<lpage>7</lpage>. <pub-id pub-id-type="doi">10.1016/j.athoracsur.2012.01.032</pub-id> <pub-id pub-id-type="pmid">22429669</pub-id></citation></ref>
<ref id="B31"><label>31.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Xu</surname> <given-names>J</given-names></name> <name><surname>Leung</surname> <given-names>D</given-names></name> <name><surname>Rajaratnam</surname> <given-names>R</given-names></name> <name><surname>Mussap</surname> <given-names>C</given-names></name> <name><surname>French</surname> <given-names>J</given-names></name> <name><surname>Juergens</surname> <given-names>C</given-names></name><etal/></person-group> <article-title>Contemporary practice of veno-arterial extracorporeal membrane oxygenation (VA-ECMO) at a single non-transplant centre: survival prediction scores, indications and outcomes.</article-title> <source><italic>Hear Lung Circ.</italic></source> (<year>2016</year>) <volume>25</volume>:<issue>S171</issue>. <pub-id pub-id-type="doi">10.1016/j.hlc.2016.06.402</pub-id></citation></ref>
<ref id="B32"><label>32.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>van den Brink</surname> <given-names>F</given-names></name> <name><surname>Zivelonghi</surname> <given-names>C</given-names></name> <name><surname>Vossenberg</surname> <given-names>T</given-names></name> <name><surname>Bleeker</surname> <given-names>G</given-names></name> <name><surname>Winia</surname> <given-names>V</given-names></name> <name><surname>Sjauw</surname> <given-names>K</given-names></name><etal/></person-group> <article-title>VA-ECMO with IABP is associated with better outcome than VA-ECMO alone in the treatment of cardiogenic shock in ST-elevation myocardial infarction.</article-title> <source><italic>J Invasive Cardiol.</italic></source> (<year>2021</year>) <volume>33</volume>:<fpage>E387</fpage>&#x2013;<lpage>92</lpage>. <pub-id pub-id-type="doi">10.1093/ehjci/ehaa946.1790</pub-id> <pub-id pub-id-type="pmid">33893793</pub-id></citation></ref>
<ref id="B33"><label>33.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Park</surname> <given-names>T</given-names></name> <name><surname>Yang</surname> <given-names>J</given-names></name> <name><surname>Choi</surname> <given-names>S</given-names></name> <name><surname>Bin Song</surname> <given-names>Y</given-names></name> <name><surname>Hahn</surname> <given-names>J</given-names></name> <name><surname>Choi</surname> <given-names>J</given-names></name><etal/></person-group> <article-title>Clinical impact of intra-aortic balloon pump during extracorporeal life support in patients with acute myocardial infarction complicated by cardiogenic shock.</article-title> <source><italic>BMC Anesthesiol.</italic></source> (<year>2014</year>) <volume>14</volume>:<issue>27</issue>. <pub-id pub-id-type="doi">10.1186/1471-2253-14-27</pub-id> <pub-id pub-id-type="pmid">24725532</pub-id></citation></ref>
<ref id="B34"><label>34.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Ostadal</surname> <given-names>P</given-names></name> <name><surname>Rokyta</surname> <given-names>R</given-names></name> <name><surname>Karasek</surname> <given-names>J</given-names></name> <name><surname>Kruger</surname> <given-names>A</given-names></name> <name><surname>Vondrakova</surname> <given-names>D</given-names></name> <name><surname>Janotka</surname> <given-names>M</given-names></name><etal/></person-group> <article-title>Extracorporeal membrane oxygenation in the therapy of cardiogenic shock: results of the ECMO-CS randomized clinical trial.</article-title> <source><italic>Circulation.</italic></source> (<year>2022</year>). <comment>[Epub ahead of print]</comment>. <pub-id pub-id-type="doi">10.1161/CIRCULATIONAHA.122.062949</pub-id> <pub-id pub-id-type="pmid">36335478</pub-id></citation></ref>
<ref id="B35"><label>35.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Ouweneel</surname> <given-names>D</given-names></name> <name><surname>Schotborgh</surname> <given-names>JV</given-names></name> <name><surname>Limpens</surname> <given-names>J</given-names></name> <name><surname>Sjauw</surname> <given-names>K</given-names></name> <name><surname>Engstr&#x00F6;m</surname> <given-names>A</given-names></name> <name><surname>Lagrand</surname> <given-names>W</given-names></name><etal/></person-group> <article-title>Extracorporeal life support during cardiac arrest and cardiogenic shock: a systematic review and meta-analysis.</article-title> <source><italic>Intensive Care Med.</italic></source> (<year>2016</year>) <volume>42</volume>:<fpage>1922</fpage>&#x2013;<lpage>34</lpage>. <pub-id pub-id-type="doi">10.1007/s00134-016-4536-8</pub-id> <pub-id pub-id-type="pmid">27647331</pub-id></citation></ref>
<ref id="B36"><label>36.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Combes</surname> <given-names>A</given-names></name> <name><surname>Montalescot</surname> <given-names>G.</given-names></name></person-group> <source><italic>Assessment of ECMO in Acute Myocardial Infarction Cardiogenic Shock (ANCHOR). NCT04184635.</italic></source> (<year>2019</year>). Available online at: <ext-link ext-link-type="uri" xlink:href="http://clinicaltrials.gov/ct2/show/NCT04184635">clinicaltrials.gov/ct2/show/NCT04184635</ext-link> (<comment>accessed November 2019</comment>).</citation></ref>
<ref id="B37"><label>37.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Vallabhajosyula</surname> <given-names>S</given-names></name> <name><surname>O&#x2019;Horo</surname> <given-names>J</given-names></name> <name><surname>Antharam</surname> <given-names>P</given-names></name> <name><surname>Ananthaneni</surname> <given-names>S</given-names></name> <name><surname>Vallabhajosyula</surname> <given-names>S</given-names></name> <name><surname>Stulak</surname> <given-names>J</given-names></name><etal/></person-group> <article-title>Concomitant intra-aortic balloon pump use in cardiogenic shock requiring veno-arterial extracorporeal membrane oxygenation.</article-title> <source><italic>Circ Cardiovasc Interv.</italic></source> (<year>2018</year>) <volume>11</volume>:<issue>e006930</issue>. <pub-id pub-id-type="doi">10.1161/CIRCINTERVENTIONS.118.006930</pub-id> <pub-id pub-id-type="pmid">30354593</pub-id></citation></ref>
<ref id="B38"><label>38.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Russo</surname> <given-names>J</given-names></name> <name><surname>Aleksova</surname> <given-names>N</given-names></name> <name><surname>Pitcher</surname> <given-names>I</given-names></name> <name><surname>Couture</surname> <given-names>E</given-names></name> <name><surname>Parlow</surname> <given-names>S</given-names></name> <name><surname>Faraz</surname> <given-names>M</given-names></name><etal/></person-group> <article-title>Left ventricular unloading during extracorporeal membrane oxygenation in patients with cardiogenic shock.</article-title> <source><italic>J Am Coll Cardiol.</italic></source> (<year>2019</year>) <volume>73</volume>: <fpage>654</fpage>&#x2013;<lpage>62</lpage>. <pub-id pub-id-type="doi">10.1016/j.jacc.2018.10.085</pub-id> <pub-id pub-id-type="pmid">30765031</pub-id></citation></ref>
<ref id="B39"><label>39.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Tongers</surname> <given-names>J</given-names></name> <name><surname>Sieweke</surname> <given-names>J</given-names></name> <name><surname>K&#x00FC;hn</surname> <given-names>C</given-names></name> <name><surname>Napp</surname> <given-names>L</given-names></name> <name><surname>Flierl</surname> <given-names>U</given-names></name> <name><surname>R&#x00F6;ntgen</surname> <given-names>P</given-names></name><etal/></person-group> <article-title>Early escalation of mechanical circulatory support stabilizes and potentially rescues patients in refractory cardiogenic shock.</article-title> <source><italic>Circ Hear Fail.</italic></source> (<year>2020</year>) <volume>13</volume>:<issue>e005853</issue>. <pub-id pub-id-type="doi">10.1161/CIRCHEARTFAILURE.118.005853</pub-id> <pub-id pub-id-type="pmid">32164431</pub-id></citation></ref>
<ref id="B40"><label>40.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>de Jong</surname> <given-names>M</given-names></name> <name><surname>Lorusso</surname> <given-names>R</given-names></name> <name><surname>Al Awami</surname> <given-names>F</given-names></name> <name><surname>Matteuci</surname> <given-names>F</given-names></name> <name><surname>Parise</surname> <given-names>O</given-names></name> <name><surname>Lozekoot</surname> <given-names>P</given-names></name><etal/></person-group> <article-title>Vascular complications following intra-aortic balloon pump implantation: an updated review.</article-title> <source><italic>Perfusion.</italic></source> (<year>2017</year>) <volume>33</volume>:<fpage>96</fpage>&#x2013;<lpage>104</lpage>. <pub-id pub-id-type="doi">10.1177/0267659117727825</pub-id> <pub-id pub-id-type="pmid">28816093</pub-id></citation></ref>
<ref id="B41"><label>41.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Jia</surname> <given-names>D</given-names></name> <name><surname>Yang</surname> <given-names>I</given-names></name> <name><surname>Ling</surname> <given-names>R</given-names></name> <name><surname>Syn</surname> <given-names>N</given-names></name> <name><surname>Poon</surname> <given-names>W</given-names></name> <name><surname>Murughan</surname> <given-names>K</given-names></name><etal/></person-group> <article-title>Vascular complications of extracorporeal membrane oxygenation: a systematic review and meta-regression analysis.</article-title> <source><italic>Crit Care Med.</italic></source> (<year>2020</year>) <volume>48</volume>:<fpage>e1269</fpage>&#x2013;<lpage>77</lpage>. <pub-id pub-id-type="doi">10.1097/CCM.0000000000004688</pub-id> <pub-id pub-id-type="pmid">33105148</pub-id></citation></ref>
<ref id="B42"><label>42.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Iannaccone</surname> <given-names>M</given-names></name> <name><surname>Venuti</surname> <given-names>G</given-names></name> <name><surname>di Simone</surname> <given-names>E</given-names></name> <name><surname>De Filippo</surname> <given-names>O</given-names></name> <name><surname>Bertaina</surname> <given-names>M</given-names></name> <name><surname>Colangelo</surname> <given-names>S</given-names></name><etal/></person-group> <article-title>Comparison of ECMO vs ECpella in patients with non-post-pericardiotomy cardiogenic shock: an updated meta-analysis.</article-title> <source><italic>Cardiovasc Revasc Med.</italic></source> (<year>2022</year>) <volume>40</volume>:<fpage>134</fpage>&#x2013;<lpage>41</lpage>. <pub-id pub-id-type="doi">10.1016/j.carrev.2021.10.001</pub-id> <pub-id pub-id-type="pmid">34654655</pub-id></citation></ref>
<ref id="B43"><label>43.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Thiele</surname> <given-names>H</given-names></name> <name><surname>Zeymer</surname> <given-names>U</given-names></name> <name><surname>Neumann</surname> <given-names>F</given-names></name> <name><surname>Ferenc</surname> <given-names>M</given-names></name> <name><surname>Olbrich</surname> <given-names>H</given-names></name> <name><surname>Hausleiter</surname> <given-names>J</given-names></name><etal/></person-group> <article-title>Intraaortic balloon support for myocardial infarction with cardiogenic shock.</article-title> <source><italic>N Engl J Med.</italic></source> (<year>2012</year>) <volume>367</volume>:<fpage>1287</fpage>&#x2013;<lpage>96</lpage>. <pub-id pub-id-type="doi">10.1056/NEJMoa1208410</pub-id> <pub-id pub-id-type="pmid">22920912</pub-id></citation></ref>
<ref id="B44"><label>44.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Schrage</surname> <given-names>B</given-names></name> <name><surname>Becher</surname> <given-names>P</given-names></name> <name><surname>Bernhardt</surname> <given-names>A</given-names></name> <name><surname>Bezerra</surname> <given-names>H</given-names></name> <name><surname>Blankenberg</surname> <given-names>S</given-names></name> <name><surname>Brunner</surname> <given-names>S</given-names></name><etal/></person-group> <article-title>Left ventricular unloading is associated with lower mortality in patients with cardiogenic shock treated with venoarterial extracorporeal membrane oxygenation.</article-title> <source><italic>Circulation.</italic></source> (<year>2020</year>) <volume>142</volume>:<fpage>2095</fpage>&#x2013;<lpage>106</lpage>.</citation></ref>
<ref id="B45"><label>45.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Pappalardo</surname> <given-names>F</given-names></name> <name><surname>Schulte</surname> <given-names>C</given-names></name> <name><surname>Pieri</surname> <given-names>M</given-names></name> <name><surname>Schrage</surname> <given-names>B</given-names></name> <name><surname>Contri</surname> <given-names>R</given-names></name> <name><surname>Soeffker</surname> <given-names>G</given-names></name><etal/></person-group> <article-title>Concomitant implantation of Impella&#x00A7;on top of veno-arterial extracorporeal membrane oxygenation may improve survival of patients with cardiogenic shock.</article-title> <source><italic>Eur J Heart Fail.</italic></source> (<year>2017</year>) <volume>19</volume>:<fpage>404</fpage>&#x2013;<lpage>12</lpage>. <pub-id pub-id-type="doi">10.1002/ejhf.668</pub-id> <pub-id pub-id-type="pmid">27709750</pub-id></citation></ref>
<ref id="B46"><label>46.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Eliet</surname> <given-names>J</given-names></name> <name><surname>Gaudard</surname> <given-names>P</given-names></name> <name><surname>Zeroual</surname> <given-names>N</given-names></name> <name><surname>Rouvi&#x00E8;re</surname> <given-names>P</given-names></name> <name><surname>Albat</surname> <given-names>B</given-names></name> <name><surname>Mourad</surname> <given-names>M</given-names></name><etal/></person-group> <article-title>Effect of impella during veno-arterial extracorporeal membrane oxygenation on pulmonary artery flow as assessed by end-tidal carbon dioxide.</article-title> <source><italic>ASAIO J.</italic></source> (<year>2018</year>) <volume>64</volume>:<fpage>502</fpage>&#x2013;<lpage>7</lpage>. <pub-id pub-id-type="doi">10.1097/MAT.0000000000000662</pub-id> <pub-id pub-id-type="pmid">28953197</pub-id></citation></ref>
<ref id="B47"><label>47.</label><citation citation-type="journal"><person-group person-group-type="author"><name><surname>Sauren</surname> <given-names>L</given-names></name> <name><surname>Reesink</surname> <given-names>K</given-names></name> <name><surname>Selder</surname> <given-names>J</given-names></name> <name><surname>Beghi</surname> <given-names>C</given-names></name> <name><surname>Van Der Veen</surname> <given-names>F</given-names></name> <name><surname>Maessen</surname> <given-names>J</given-names></name></person-group>. <article-title>The acute effect of intra-aortic balloon counterpulsation during extracorporeal life support: an experimental study.</article-title> <source><italic>Artif Organs.</italic></source> (<year>2007</year>) <volume>31</volume>:<fpage>31</fpage>&#x2013;<lpage>8</lpage>. <pub-id pub-id-type="doi">10.1111/j.1525-1594.2007.00337.x</pub-id> <pub-id pub-id-type="pmid">17209958</pub-id></citation></ref>
</ref-list>
</back>
</article>