STRIVE-2 MRI-Defined Brain Frailty and Functional Outcomes After Thrombectomy: A Multicenter Study

Background and Objectives: 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 MRI-defined CSVD markers before MT predict 90-day functional outcomes and hemorrhagic transformation. Methods: 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 [WMH], 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 odds ratios (aOR) and 95% credible intervals (CrI), adjusting for age, sex, thrombolysis, infarct volume, time-to-puncture and reperfusion status. A composite CSVD score including all 5 markers was also evaluated. Results: Among 479 patients (median age 72 years [IQR 59–80]; 46% female), successful reperfusion (mTICI 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 5-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 SICH (aOR 1.33; 95% CrI 0.92–1.93; PP 94%). Discussion: Preexisting 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. These findings suggest that while CSVD assessment improves post-thrombectomy prognostication, it should not be used as a criterion to preclude patients from MT eligibility.