Influence of Operator Board-Certification Status on Outcomes of Mechanical Thrombectomy: A Single-Center Retrospective Study.

Objective: Mechanical thrombectomy (MT) is the standard of care for acute ischemic stroke, and its outcomes are highly dependent on operator experience. While integrating junior physicians into MT practice is crucial for sustainable workforce development, it poses a challenge in maintaining procedural quality during their training. Although the Japanese Society for Neuroendovascular Therapy (JSNET) provides a board certification system in Japan, the impact of an operator's certification status on MT outcomes remains uncertain. Therefore, this study aimed to validate the safety and efficacy of MT performed by noncertified operators under specialist supervision by comparing their outcomes with those achieved by board-certified specialists. Methods: We conducted a single-center retrospective study of patients undergoing MT between January 2020 and December 2024. Patients were stratified into 2 groups based on the primary operator's certification status. Primary outcomes were assessed across 3 domains: efficacy (successful reperfusion, defined as a modified Thrombolysis in Cerebral Infarction score ≥2b, and favorable functional outcome, defined as a 90-day modified Rankin Scale score of 0-2), safety (symptomatic intracranial hemorrhage [sICH]), and efficiency (puncture-to-reperfusion time). Secondary efficacy measures included the modified 1st-pass effect (mFPE) and the number of passes. Multivariable logistic regression analysis was performed to evaluate whether operator certification status was independently associated with clinical outcomes. In all procedures performed by noncertified operators, a JSNET board-certified specialist was scrubbed in and provided direct supervision. Results: Eighty-seven patients met the inclusion criteria. Forty-three were treated by board-certified specialists and 44 by noncertified operators under direct supervision. The groups did not differ significantly in efficacy outcomes, including successful reperfusion (97.7% in board-certified vs. 93.2% in noncertified; p = 0.62), favorable functional outcome (51.2% vs. 43.2%; p = 0.46), and the achievement of mFPE (65.1% vs. 52.3%; p = 0.22). The primary safety outcome of sICH was also comparable (7.0% vs. 9.1%; p = 1.00). However, the efficiency outcome, puncture-to-reperfusion time, was significantly shorter in the board-certified group (median, 29 vs. 38 minutes; p = 0.02). In the multivariable analysis, only younger age and mFPE achievement were independently associated with favorable outcome, whereas the operator's certification status was not (p = 0.75). Conclusion: Under direct supervision, MT performed by noncertified operators demonstrated comparable efficacy and safety to procedures performed by board-certified specialists, albeit with lower efficiency. These data endorse structured, supervised training pathways that protect patient outcomes while developing the next generation of neurointerventionalists.