Acute ischemic stroke (AIS) has been considered one of the major causes of mortality and morbidity worldwide. In 2015, a series of randomized controlled trials (RCTs) proved the superiority of mechanical thrombectomy (MT) over standard medical therapy in treating patients with acute ischemic stroke (AIS) and large vessel occlusion (LVO) in the anterior circulation (1). Later trials further extended the efficacy of MT in treating AIS patients with extended time-window (2, 3). As such, recent guidelines from the American Heart Association/American Stroke Association (AHA/ASA) recommended MT as the first-line therapy for AIS-LVO (4).

The continued breakthrough of MT largely relies on the advancement of mechanical devices. Thrombectomy devices, with distinct mechanisms of action, may directly impact clinical consequences. MT was performed using stent retriever (SR) of the second-generation in previous RCTs (1). Thereafter, a direct aspiration first pass technique (ADAPT), with a large-bore catheter to aspirate the thrombus, was shown to have comparable effectiveness when compared with first-line SR in the Contact Aspiration vs. Stent Retriever for successful Revascularization (ASTER) trial (5) and the Comparison of Direct Aspiration Vs. Stent Retriever as a First Approach (COMPASS) (6) trial. Thus, direct aspiration thrombectomy as first-pass MT is currently considered as noninferior to SR for patients with AIS-LVO patients (COR I, LOE B-R) by AHA/ASA guidelines (4).

Aspiration force and efficacy was reported to be closely related with catheter inner diameter (ID) (7). Thus, technical advancements in catheters mainly focused on improving the deliverability as well as larger ID at both the distal end that engages the thrombus as well as the proximal end. Currently, several large-bore aspiration catheters are available on the market with refinements, in large part driven by technological advancements, such as Sofia Plus 0.070”, (MicroVention, California, USA), ACE64 (0.064”), and ACE68 (0.068”) catheters (Penumbra, California, USA) (7, 8). To better meet the rapidly growing demand for thrombectomy devices in China, several aspiration devices have been approved by the China Food and Drug Administration (CFDA), but few of them have been industrially manufactured in the country. The aim of this study was to investigate the safety and effectiveness of the Esperance^® Distal Access Catheter 0.071” (Wallaby, Shanghai, CN), a novel large bore aspiration catheter in treating AIS based on multicenter data.

Results from this clinical trial support the safety and efficacy of the Esperance^® Distal Access Catheter (0.071”) in AIS patients with LVO, treated with the ADAPT technique. Of the 160 patients, 147(91.9%) cases had successful reperfusion (mTICI 2b-3) with aspiration alone, and 99 (62.3%) cases had a favorable outcome (mRS 0–2) at 90 days. The time between groin puncture to successful revascularization was 44 (IQR 33,62) min. Regarding safety endpoints, the morbidity rate at 90 days was favorable 13.8% and the sICH rate within 24–36 h after procedure was 3.8%. The results were similar to previous reports from the PROMISE study using ACE68/ACE64 catheters (9).

In the past 5 years, ADAPT has become commonly employed as a first-line choice for treating AIS-LVO. The Esperance^® Distal Access Catheter, a novel large bore aspiration catheter, has a larger internal diameter (0.071”), which enable both greater aspiration force and faster aspiration speed to address the challenges of direct aspiration in the context of high thrombus load. This aspiration device also demonstrates excellent flexibility and trackability, owing to its thinner wall (0.005”) and smaller outer diameter (0.0810”), to traverse tortuous vessels and access vascular lesions during intervention. This new catheter system allows for rapid and effective revascularization by using a variety of endovascular techniques, with excellent kink resistance.

Larger bore catheters may have several advantages, such as convenience of use, higher rates of achieving successful reperfusion, lower rates of rescue therapy, and faster time to revascularization (10). In a retrospective database among 510 patients with the largest experience of ADAPT, catheters with a larger diameter could yield more frequent technical success and better clinical outcomes when compared with smaller catheters (7). Successful reperfusion with aspiration alone was 85% using ACE 64.064” and with 81% ACE 68.068”, and the use of SR was respectively 29 and 28%. In a recent meta-analysis of first-line Sofia catheters, the successful reperfusion rate was 71.6% (95%CI, 66.3–76.5%) with an SR rescue rate of 24.1% (95%CI, 17.7–31.9%). The overall final successful reperfusion rate was 88.9% (95%CI, 82.6–93.1%) (11). At the same time, in previous studies using SR, relatively lower successful reperfusion rates were reported [HERMES meta-analysis 71%, (1) ASTER 83.1%, (5) COMPASS 89% (6)]. The recently published ASTER-2 trial showed successful reperfusion was 86.2% in the combined approach group and 72.3% in the SR alone group (12). In our study, the rate of successful reperfusion with aspiration alone and at final angiography was 91.9 and 98.14%, with a lower rescue rate using SR (9.9%). Thus, the Wallaby aspiration catheter system was shown with better, or at the very least, comparable efficacy in successful revascularization of occluded vessels compared with other modern thrombectomy devices.

The FPE and mFPE are new metrics to evaluate the efficacy of thrombectomy devices (13). Previous meta-analyses reported better clinical outcomes with FPE or mFPE when compared with a multiple-pass effect (MPE) in patients with AIS-LVO (14). The mFPE was achieved in 69.7% of cases in a multicenter retrospective study of the Sofia aspiration catheter (15). Another study showed an mFPE rate of 67% when using the Sofia Plus catheter with a soft-tipped, braided distal lumen of 0.070-inch (15). The retrospective study by Alawieh et al. showed that the rate of reperfusion at first pass ranged from 55 to 68% among different types of aspiration devices (5 MAX 0.054” 55%, ACE 0.060” 63%, ACE 64.064” 63%, and ACE 68.068” 68%) (7). The rate of mFPE was 64.6% in our study, which was similar to the aforementioned. In addition, the rate of achieving complete reperfusion was 43.5% in our study and was comparable to the 47% reported in a previous study using Sofia Plus (8). Even when compared with recent ASTER-2 trial, the rate of FPE and mFPE in our study was higher than 40.9 and 53.7% rates reported for the combined approach group, and 33.7 and 44.6% in the SR group (12). The favorable outcome rate was 62.3% in this study, and it was acceptable compared with other studies (1). The overall rate of procedure-related complications including arterial perforation, dissection, and distal embolization was 10% in this study, which was comparable to 7.1% in a meta-analysis of Sofia use (11), and lower than 13% in the aspiration arm of the COMPASS trial (6), 25.1% in the combined approach and 24.3% in SR arm in ASTER-2 (12). Also, the rate of mortality (13.8 vs. 19%) and sICH (3.8 vs. 5.8%) was similar to the recent meta-analysis of Sofia use (11). Thus, despite a relatively larger bore, the Wallaby aspiration catheter system did not increase safety events.

The limitations of this study include the relatively small sample size, and the study was single-armed without direct comparison with other aspiration devices. Also, the study may be subject to selection bias as aspiration catheter selection in each case was discretionary. SNAKE technique is one of the main advantages of ADAPT but was not specifically analyzed during this trial. Other detailed information of the techniques used during conversion to stent-retriever or occlusion location after the initial ADAPT were not documented but may provide more valuable information of knowing this new thrombectomy device capacity. Furthermore, patients with anterior and posterior occlusions were both recruited, potentially leading to heterogeneity of the study population.

In current practice, the first-line aspiration approach with the Esperance^® Distal Access Catheter offers safe and efficient outcomes. The device could achieve high reperfusion rate with low requirement for rescue therapy with stent retriever.

The original contributions presented in the study are included in the article/Supplementary Material, further inquiries can be directed to the corresponding authors.

The studies involving human participants were reviewed and approved by Xuanwu Hospital of Capital Medical University, Anhui Provincial Hospital of Anhui Medical University, Sichuan Provincial People's Hospital, The First Affiliated Hospital of Wannan Medical College, Cangzhou Central Hospital, Xinqiao Hospital, The Second Affiliated Hospital, Eastern Theater General Hospital of the Chinese People's Liberation Army, Drum Tower Hospital of Medical School of Nanjing University and General Hospital of Northern Theater Command. The patients/participants provided their written informed consent to participate in this study.

All authors listed have made a substantial, direct, and intellectual contribution to the work and approved it for publication.

This study was funded by Shanghai Wallaby Medical Technologies Co., Inc.

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.

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