ObjectivesHeart failure may result in reduced brain perfusion, limiting the blood flow needed to achieve clinical recovery. We investigated whether plasma levels of brain natriuretic peptide (BNP), a biological marker of heart failure, were related to clinical outcomes after mechanical thrombectomy (MT). Materials and MethodsData were analyzed from stroke patients with internal carotid or middle cerebral artery occlusion enrolled in the SKIP trial for whom plasma level of BNP was evaluated on admission. Favorable outcome was defined as a modified Rankin scale score of 0–2 at 3 months. ResultsAmong 169 patients (median age, 74 years; 62% men, median National Institutes of Health Stroke Scale score, 18), 104 (62%) achieved favorable outcomes. Median plasma BNP level was lower in the favorable outcome group (124.1 pg/mL; interquartile range [IQR], 62.1–215.5 pg/mL) than in the unfavorable outcome group (198.0 pg/mL; IQR, 74.8–334.0 pg/mL; p=0.005). In multivariate regression analysis, the adjusted odds ratio for BNP for favorable outcomes was 0.971 (95% confidence interval, 0.993–0.999; p=0.048). At 3 months after onset, the favorable outcome rate was lower in the ≥186 pg/mL group (45%) than in the <186 pg/mL group (72%; p=0.001). This significant difference remained regardless of the presence of atrial fibrillation (AF), with rates of 47% and 76%, respectively, in AF patients (p=0.003) and 33% and 68%, respectively, in patients without AF (p=0.046). ConclusionHigh plasma BNP concentration appears associated with unfavorable outcomes after MT.