Clinical outcomes of first-pass effect after mechanical thrombectomy for acute ischemic stroke: A systematic review and meta-analysis.

Objective: The first-pass effect (FPE) during a mechanical thrombectomy for ischemic stroke results in favorable clinical outcomes and low symptomatic intracranial hemorrhage (sICH) rates according to individual observational studies. We performed an integrated study-level meta-analysis to compare the clinical outcomes and safety profiles of single (FPE group) and multiple passages (non-FPE group) of devices in patients who achieved successful recanalizations.

Methods: A literature search of the PubMed, Embase, and Cochrane databases for FPE was conducted. We included studies comparing outcomes between patients with and without FPE for 90-day favorable outcome, mortality, and sICH. The results from the pooled analysis using the random-effects model were presented as odds ratios (OR) and 95% confidence intervals (CI).

Results: Of the 8 selected studies comprising 2308 patients, the overall rates of the FPE were 40.3% (930/2308). The FPE was significantly associated with more 90-day favorable outcomes (OR: 1.31, 95% CI: 1.13-1.51) and lower mortality (OR: 0.53, 95% CI: 0.34-0.81), but there were no significant differences in sICH rates (OR: 0.80, 95% CI: 0.50-1.30). The results of the meta-regression analysis showed that there was no confounding effect of intravenous thrombolysis prior to thrombectomy.

Conclusion: Our findings indicated that patients who achieved the FPE would have more 90-day favorable outcomes and lower mortality compared with non-FPE patients. However, there was a limited association between the FPE and reduced sICH rates.