Inter-proceduralist variability in angiographic outcomes after stroke thrombectomy and the importance of quality over quantity of passes.

Background: Complete recanalization (CR, modified Treatment in Cerebral Ischemia (mTICI) score of 2c or better) is associated with favorable outcomes after endovascular thrombectomy (EVT) for stroke patients. However, the degree of inter-proceduralist differences in CR rates is unknown, and whether higher CR rates are being achieved by performing more passes or by focusing on first-pass effectiveness is also unclear.

Methods: This was a multicenter retrospective study of anterior circulation large vessel occlusion stroke patients in the United States from 2016 to 2022. Patients treated by proceduralists with at least 50 cases were included. CR rates for each proceduralist were assessed and proceduralists were divided into tertiles. First-pass effect (FPE, defined as CR after one pass) and the number of passes for patients treated by the top tertile of proceduralists were compared with the bottom tertile. Mediation analyses were conducted to assess causal links between CR rates and number of passes or FPE.

Results: A total of 1096 EVTs performed by 11 proceduralists were identified. CR rates were highly variable across providers (43.1% to 75.3%, p<0.001). Patients treated by the top tertile were more likely to experience FPE (OR 1.99, 95% CI 1.49 to 2.67, p<0.001) and did not undergo more passes (p=0.69) compared with the bottom tertile. Higher rates of FPE among patients was a significant mediator of higher odds of CR among patients treated by the top tertile (p<0.001).

Conclusions: Angiographic outcomes among EVT proceduralists are highly variable. Proceduralists who achieve higher rates of CR are doing so with higher rates of FPE, not more passes.