STRIVE-2 MRI-defined brain frailty and functional outcomes after thrombectomy: A multicenter study

Mechanical thrombectomy (MT) is the standard of care for large vessel occlusion (LVO) stroke, yet nearly half of patients fail to achieve functional independence. Cerebral small vessel disease (CSVD) represents a marker of brain frailty that may impair recovery. We aimed to evaluate whether comprehensive magnetic resonance imaging (MRI)-defined CSVD markers before MT predict 90-day functional outcomes and hemorrhagic transformation.

This retrospective, multicenter cohort study analyzed consecutive patients with anterior circulation LVO treated with MT (2015-2022) at two tertiary centers. CSVD markers (white matter hyperintensities (WMHs), lacunes, cerebral microbleeds (CMBs), enlarged perivascular spaces (EPVS), and brain atrophy) were assessed on pre-treatment MRI according to STRIVE-2 criteria. The primary outcome was functional dependence or death at 90 days (modified Rankin Scale (mRS) score 3-6). Bayesian logistic regression models estimated adjusted odds ratios (aORs) and 95% credible intervals (CrI), adjusting for age, sex, thrombolysis, infarct volume, time-to-puncture, and reperfusion status. A composite CSVD score including all five markers was also evaluated.

Among 479 patients (median age 72 years (interquartile range = 59-80); 46% female), successful reperfusion (modified thrombolysis in cerebral infarction 2b-3) was achieved in 83% and 47% had 90-day mRS 3-6. Functional dependence was independently associated with the presence of lacunes (aOR = 2.07; 95% CrI = 1.22-3.59; posterior probability (PP) > 99%), moderate-to-severe brain atrophy (aOR 1.92; 95% CrI = 1.09-3.40; PP 99%), and moderate-to-severe WMH (aOR = 1.63; 95% CrI = 0.94-2.84; PP = 96%). Furthermore, every 1-point increase in the five-item composite CSVD score demonstrated a dose-dependent increase in the odds of functional dependence (aOR = 1.44; 95% CrI = 1.23-1.69; PP > 99%) and symptomatic intracerebral hemorrhage (aOR = 1.33; 95% CrI = 0.92-1.93; PP = 94%).

Pre-existing lacunes, atrophy, and WMH are independent determinants of worse functional recovery after MT. Importantly, cumulative total CSVD burden acts as a strong, dose-dependent predictor of functional outcomes and symptomatic hemorrhage. While these findings support that CSVD assessment improves post-thrombectomy prognostication, they do not support CSVD be used as a criterion to preclude patients from MT eligibility.