Among AIS patients treated with EVT, our study demonstrated that prior antiplatelet (PA) use significantly reduced the 3-month death without increasing the risk of ICH. However, PA did not modify the 90-day functional outcome.
Our study in a Chinese population demonstrated that PA significantly reduced the 3-month death during the follow-up. When IS occurs, restoring vascular patency for reperfusion treatment in a short period is necessary, which is crucial for reducing mortality [22]. In our study, the rate of successful reperfusion of blood vessels in patients receiving PA therapy was higher than in patients who did not (90.7% vs 84%, P = 0.208). Similar findings were reported by Dicpinigaitis et al. [23]. Their study found that patients with PA demonstrate lower mortality rates (7.0% vs 10.1%, p < 0.001). However, Merlino et al. [18] revealed that 3-month mortality was significantly higher in patients with PA than in those without PA. Our research was conducted among Chinese people. It is worth considering that there are significant differences in baseline characteristics among these studies, such as race, age, sex and so on, making it difficult to avoid random errors, which may affect the comparability and accuracy of results. All in all, large muti-center and multi-race cohorts are warranted to verify these findings.
Our research findings indicate that PA does not significantly improve the long-term functional prognosis of patients. The lack of association between PA and disability rate may be due to the NIHSS score and stroke etiology in the present study. Because most strokes were attributed to cardioembolism in the PA group, these patients have a higher baseline NIHSS score, which means that the long-term poor prognosis rate of these patients will increase [24, 25]. Likewise, Krieger et al. [26] and Couture et al. [27] found that PA in AIS patients treated with EVT significantly increases the risk of poor functional outcome at 90 days.
Successful recanalization of cerebral blood vessels following EVT is one of the potential predictors for good long-term outcomes in patients with AIS. However, the efficacy of EVT-induced recanalization can be hampered by re-occlusion caused by platelet aggregation within the first 24 hours. Prior antiplatelet [28] may play a role in early recanalization and modify clinical outcomes in AIS patients receiving reperfusion treatment. Merlino et al. [18] and Pandhi et al. [19] found that patients accepted with prior antiplatelet have higher successful recanalization rates. Sohn et al. [16] found that PA can reduce futile reperfusion and stroke progression. However, our results showed a higher recanalization rate, but the difference did not lead to statistical significance. Similarly, other studies[17, 20, 29, 30] have found no significant association between PA and successful recanalization. There may be two reasons for the differences between our study and previous studies. Firstly, Sohn et al. [16] only investigated the effect of single antiplatelet drugs on vascular recanalization. Secondly, our study was conducted later than the studies of Merlino et al. [18]. Pandhi et al. [19], and factors such as using second-generation thrombectomy devices and more standardized thrombectomy procedures also led to a higher rate of successful recanalization, weakening the beneficial effect of PA therapy on successful reperfusion of blood vessels. In terms of the results of subgroup analysis, patients who received prior statin and antiplatelet treatment had a higher chance of successful recanalization than patients who received prior statin and not antiplatelet treatment (96.7% vs 75.0%, p = 0.031). In summary, prior antiplatelet treatment efficacy on the recanalization rate warrants further verification.
Our analyses showing that PA has no significant effect on the early improvement of neurological function are similar to those of Graaf et al. [20]. Up to now, there has been little discussion and research on improving neurological function through prior antiplatelet therapy, and this finding warrants further verification.
We confirmed that prior antiplatelet is safe in AIS patients receiving EVT, with no significant increase in the risk for ICH. These results are consistent with previous studies [16–20] but contrary to Sugiura et al. [31] and Couture et al. [27]. Firstly, in the Japanese study performed from 2010 to 2011 [31], patients were treated with older-generation devices, and intra-arterial thrombolysis was delivered in 21% of patients' cohorts; the findings should be considered with caution. Secondly, although both Couture et al.’s [27] study and our study are prospective, less than 80 AIS patients were using antiplatelet drugs before stroke. The small sample size and poor statistical power may have led to random errors. In conclusion, whether PA can reduce the risk for ICH among AIS patients with EVT is still controversial and needs to be confirmed by large-scale, high-quality clinical studies with different etiologies and races.
The present study had some strengths. The patients were enrolled prospectively and consecutively. After key endovascular treatment trials were published, all AIS patients were treated with new devices. However, our study has several limitations. First, patient recruitment in the present study was from only two Chinese stroke centers. Consequently, the bias of patient selection was inevitable. Secondly, patients included in the cohort were confined to the Chinese population. Prior studies [32] have identified a vast atherosclerosis burden in Asians. However, we still need to perform a subgroup analysis by stroke etiology. Thirdly, as the sample size was relatively small, we could not investigate the effect of prior single or dual antiplatelet agents on clinical outcomes.