Effect of Proximal Blood Flow Arrest During Endovascular Thrombectomy (ProFATE): A Multicenter, Blinded-End Point, Randomized Clinical Trial

BACKGROUND: The effect of temporary blood flow arrest during endovascular thrombectomy for acute ischemic stroke is uncertain due to the lack of evidence from randomized controlled trials. We aimed to investigate whether temporary blood flow arrest during endovascular thrombectomy using a balloon guide catheter improves intracranial vessel recanalization compared with nonflow arrest. METHODS: The ProFATE trial (Proximal Blood Flow Arrest During Endovascular Thrombectomy) was a multicenter, randomized, participant- and outcome-blinded trial at 4 thrombectomy centers in the United Kingdom. Adults with acute ischemic stroke due to anterior circulation large vessel occlusion were randomly assigned (1:1) by a central, Web-based program with a minimization algorithm to undergo thrombectomy with temporary proximal blood flow arrest or nonflow arrest during each attempt. The primary outcome was the proportion of participants achieving near-complete/complete vessel recanalization (expanded Thrombolysis in Cerebral Infarction score of 2c or 3) at the end of the thrombectomy procedure, adjudicated by a blinded independent imaging core laboratory. Analyses were performed on the intention-to-treat population, adjusted for age, IV thrombolysis, onset-to-randomization time, Alberta Stroke Program Early CT Score, occlusion site, randomization site, and National Institutes of Health Stroke Scale. RESULTS: Between October 10, 2021, and June 27, 2023, we recruited 134 participants, of whom 131 participants (mean age, 75 years; 62 [47%] women and 69 [53%] men) were included in the final analysis. Sixty-six participants were allocated to the temporary blood flow arrest group and 65 to the nonflow arrest group. The proportion of participants with an expanded Thrombolysis in Cerebral Infarction 2c/3 score at the end of the endovascular procedure was 74.4% (49/66) in the flow arrest group and 70.8% (46/65) in the nonflow arrest group (adjusted odds ratio, 1.07 [95% CI, 0.45-2.55]; P=0.88). Among the prespecified secondary efficacy outcomes, a lower rate of emboli to a new vascular territory occurred in the blood flow arrest group compared with the nonflow arrest group (1.5% versus 12.3%; adjusted odds ratio, =0.04 [95% CI, 0.01-0.53]; P=0.014) and a higher rate of complete recanalization (expanded Thrombolysis in Cerebral Infarction score, 3) after the first attempt in the flow arrest group versus the nonflow arrest group (33.0% versus 15.3%; adjusted odds ratio, =3.80 [95% CI, 1.40-10.01]; P=0.007). No between-group differences were identified for the remaining procedural or clinical efficacy (modified Rankin Scale at 90 days) or safety outcomes (worsening of the stroke severity at 24 hours, adverse events, symptomatic intracranial hemorrhage, or mortality). CONCLUSIONS: Among patients presenting with anterior circulation large vessel occlusion acute ischemic stroke, temporary proximal blood flow arrest during endovascular thrombectomy, compared with nonflow arrest, did not significantly improve the near-complete/complete vessel recanalization (expanded Thrombolysis in Cerebral Infarction score, 2c-3) at the end of the procedure. Larger randomized controlled trials are warranted to confirm or refute a clinically significant treatment effect of temporary flow arrest on the functional outcome following endovascular thrombectomy.