(YNRF) A Multicenter International Study on Incidence and Predictors of Poor Functional Outcomes Despite Successful Endovascular Recanalization in Acute Stroke

Introduction: Despite high efficacy of endovascular thrombectomy in improving outcomes following acute ischemic stroke, less than 50% of patients with successful recanalization achieve functional independence at 90 days. We explored demographic, radiographic, and procedural variables predicting mismatch between successful recanalization and functional outcomes after thrombectomy using the STAR registry.

Methods: Patients undergoing thrombectomy at 32 global centers were reviewed from the Stroke Thrombectomy and Aneurysm Registry, an international multicenter registry of patient outcomes. Successful recanalization was defined as Thrombectomy in Cerebral Ischemia (TICI) score 2B, 2C or 3 corresponding to over 50% reperfusion of the target territory. Functional outcome was measured by modified Rankin Score for disability at 90days, with 0-2 considered good outcome. Only patients with successful recanalization were included and dichotomized based on functional outcome. TICI-Rankin mismatch was defined as poor outcome despite successful recanalization. Univariate and multivariate analyses for predictors of functional outcome were included.

Results: In total, 6693 patients were included. Good outcome was achieved in 42%, TICI-Rankin mismatch rate was 58%, and mortality rate was 18% by 90days. Independent predictors of TICI-Rankin mismatch: female gender (aOR=1.6,p < 0.01), black race (aOR=1.4,p < 0.01), age (aOR=1.3,p < 0.01), baseline disability (aOR=1.6,p < 0.05), admission stroke scale (aOR=1.1,p < 0.01), and favorable ASPECT score (aOR=0.5,p < 0.01). Procedural variables independently predicting higher rates of TICI-Rankin mismatch: procedure time >60 min (aOR=1.6,p < 0.01), >2 attempts (aOR=1.9,p < 0.01), post-operative hemorrhage (aOR=4.7,p < 0.01), and intra-operative complications (aOR=1.6,p < 0.01). The mismatch rate had significant linear correlation with age (6% increase per 10 years), attempts (6% increase with each attempt), and procedure time (2% increase with each 30 min). The mismatch rate did not correlate with the TICI score (2B vs 2C vs 3) in recanalized patients.

Conclusion : TICI-Rankin mismatch after ischemic stroke thrombectomy depends on baseline functional status and rapid intra-operative recanalization. Post-operative hemorrhage is a major contributor to the mismatch.