Older age is a major factor that contributes to stroke occurrence and poor stroke outcomes (1). It is expected that the number of acute ischemic stroke cases in older adults will continue to increase owing to population growth, the global aging population, and advances in stroke treatment (2, 3). Thus, the problem of acute ischemic stroke treatment in older adults has become increasingly significant. The benefits of homogenizing mechanical thrombectomy in older adults are still controversial. A subgroup analysis of the Highly Effective Reperfusion Evaluated in Multiple Endovascular Stroke Trials (HERMES) collaboration showed that patients aged ≥ 80 years might benefit from endovascular treatment (EVT) more than from conservative treatment (4). Conversely, the NASA registry reported that an age greater than 80 years is predictive of poor clinical outcomes and increased mortality compared with younger patients (5). Ali Alawieh et al. (6) retrospectively analyzed prospective database data of patients with acute ischemic stroke (AIS) receiving EVT in seven comprehensive stroke centers in the United States. The results showed that the 90-day mortality rate was higher than in the young group. This result may be attributed to the probability of bleeding after thrombectomy in the older adult group being significantly higher than that in the young group, and the proportion of patients with good prognoses showed a downward trend.

With the available research data primarily from Western populations, the information available regarding efficacy and safety in the Asian population is lacking. Moreover, the Asian population has different features compared with the Western populations in most of the previous trials and registries, such as more prevalent intracranial atherosclerotic disease (ICAD). Recently, the prospective Chinese Endovascular Treatment Key Technique and Emergency Work Flow Improvement of Acute Ischemic Stroke (ANGEL-ACT Registry) was conducted to evaluate the utilization and subsequent outcomes of EVT-treated AIS patients. Therefore, our study aimed to evaluate the safety and efficacy of mechanical thrombectomy in older adults in China and provide real-world evidence of the effectiveness of EVT in older adults.

This subgroup analysis of patients with large vessel occlusion (LVO) from the ANGEL-ACT registry found no significant differences between the older and younger populations at 90 days after EVT in terms of safety outcomes. Nevertheless, older adults had a lower rate of moderate functional independence (mRS 0–3) when compared with the younger population. A significantly higher incidence of coronary heart disease, atrial fibrillation history, and higher NIHSS on admission may account for this finding.

The benefits of endovascular therapy (EVT) in older adults with AIS with LVO remain controversial (12–14). A recent meta-analysis conducted by the HERMES collaborators demonstrated that older adults aged ≥ 80 years may benefit more from EVT than conservative treatment (4). However, the results of this study should also be interpreted cautiously, owing to the relatively small number of older adults in this study. Moreover, the elderly typically have more comorbid conditions; therefore, strict patient selection is required. EVT should be performed only in patients who qualify as a registry study based on Solitaire FR stent thrombectomy in North American patients with acute ischemic stroke showed that older age was an independent factor contributing to poor prognosis and high morbidity and mortality rates for mechanical thrombectomy compared with the younger age group (5). This result was supported by the previous relevant studies (6, 15–17) and the recent endovascular Treatment for Acute Ischemic Stroke in the Netherlands (MR CLEAN) Registry study (18).

Our study showed a more neutral result, which is consistent with a previously reported study (19). The rates of excellent outcomes and functional independence among older adults who underwent EVT were comparable to those among younger patients. The fact that there was a higher rate of successful recanalization despite a statistically insignificant difference between the groups may be attributed to this neutral outcome (91.2% vs. 89.1%, p = 0.417). Furthermore, shorter onset-to-recanalization times in the elderly group may result in less expansion of the infarct (20). Currently, there is a lack of information in the literature as all the research has been conducted on Western populations. To our knowledge, this study represents the first analysis of real-world multicenter data examining age disparities in EVT in the Chinese population. This result also raises the possibility that social or cultural factors and patient eligibility may have contributed to these differences.

Furthermore, there was no significant difference between the younger and older adults regarding 90-day mortality. However, an age < 80 years was associated with a higher rate of moderate functional independence (OR 0.64, 95% CI 0.44–0.94, p = 0.022). The presence of atrial fibrillation and cardiogenic embolism was significantly higher in the elderly than in the younger age group, which might explain this finding. The results of our study are in accordance with previous findings, which reported that cardiogenic embolisms have a less favorable prognosis than large atherosclerotic occlusions due to a lack of collateral circulation (21). This finding might partially explain the lower NIHSS scores at admission in the younger population.

Despite our result showing that EVT is relatively safe in older age, performing early cerebral hemodynamic assessments in elderly patients before and after MT, including transcranial Doppler ultrasound and cerebral perfusion imaging, may reduce the risk of hyperperfusion injury and intracranial hemorrhage. Blood pressure management after recanalization requires further research and may be related to the degree of reperfusion and infarct volume. Moreover, postoperative care is imperative, and patients should be treated using a multidisciplinary approach. A large number of prospective clinical trials are required to address this issue.

A major strength of our study is the large sample size. In addition, since the data were drawn from a prospective national registry of consecutive patients, they may well be representative of actual clinical practice with regard to EVT. However, this study had several limitations. First, despite conventional multivariable analysis and adjustment of the propensity score, this study was not a randomized trial and, therefore, may have resulted in a selection bias. Second, our unscheduled subgroup analysis could not reach any firm conclusions; selective biases need to be considered, and the corresponding results should be interpreted with caution. Third, although these patients were all treated according to the guidelines for EVT, their surgical strategies and postoperative management differed between the hospitals. This may have affected the results to some extent. Furthermore, rehabilitation and psychosocial factors may have a more significant influence on stroke recovery in older adults than in younger adults, but their impact on AIS LVO post-EVT outcomes remains to be explored. Finally, the present study was conducted in the Chinese population; thus, this finding cannot be easily extrapolated to other populations.

Our results showed that there was no significant difference in the safety and efficacy outcomes (mRS 0–1 and mRS 0–2) between older adults and younger patients who underwent mechanical thrombectomy. However, older adults had a lower rate of moderate functional independence (mRS 0–3) when compared with the younger population. These findings emphasize the need to develop stricter selection criteria for older adults. However, further randomized clinical trials are required to verify this finding.

The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.

The studies involving human participants were reviewed and approved by NCT03370939. The patients/participants provided their written informed consent to participate in this study.

ZM supervised and performed quality control for the study. AW performed the statistical analysis. BH, DS, and Raynald acquired the data and wrote the manuscript with input from BJ, XT, AW, DM, FG, NM, and ZM. All authors contributed to the article and approved the submitted version.

This work was supported by the National Key Research and Development Program of China, Grant Number 2016YFC1301500 and China Postdoctoral Science Foundation, grant number 2020-YJ-008.

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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