Abstract Body: Background: Complete recanalization, defined as modified Treatment in Cerebral Ischemia (mTICI) score of 2c or better, has been shown to be superior to mTICI 2b in terms of patient outcomes following stroke thrombectomy. While some proceduralists achieve higher rates of complete recanalization than others, the driving factors underlying provider-specific differences are not well understood.
Methods: This was a retrospective study of stroke thrombectomy cases at three large comprehensive stroke centers. Patients treated by high-volume proceduralists (50 cases or more per proceduralist) were included. The rate of complete recanalization for each proceduralist was calculated and inter-proceduralist variability was assessed; proceduralists were then divided into tertiles based on these rates. First pass effect (FPE, defined as complete recanalization after one pass) and the number of passes for patients treated by the top tertile of proceduralists were compared to those treated by the bottom tertile using multivariable regression models. Mediation analyses were conducted to assess causal links with FPE and number of passes.
Results: A total of 1,137 thrombectomy cases performed by 11 high-volume proceduralists were identified. Overall, there was significant variability in complete recanalization rates across providers (range 44.0% to 75.8%, p<0.001; Figure 1). Patients treated by the top tertile of proceduralists in terms of complete recanalization rates were significantly more likely to experience FPE (OR 2.17 [95%CI 1.55 to 3.06], p<0.001; Figure 2), and they did not undergo more EVT passes (rate ratio 1.02 [95% 0.93 to 1.12], p=0.72; Figure 2) compared those treated by the bottom tertile. The higher rates of FPE among patients treated by the top tertile partially explained their higher odds of complete recanalization (46% mediation [95%CI 27% to 66%], p<0.001), whereas the number of passes did not (5% mediation [95%CI -5% to 20%], p=0.23).
Conclusions: Complete recanalization rates among high-volume thrombectomy proceduralists are highly variable. Proceduralists who achieve higher rates of complete recanalization are doing so in large part due to higher rates of FPE, not additional attempts. Future efforts are needed to identify factors associated with FPE, such as patient characteristics, device choice, procedural technique, and proceduralist training.