Abstract / Summary
BACKGROUND: Reperfusion injury (RI) is a major contributor to poor outcomes after successful recanalization in anterior circulation-large vessel occlusion. White matter hyperintensities (WMH) reflect chronic microvascular injury and are often associated with blood-brain barrier dysfunction or cerebral autoregulation impairment and may increase vulnerability to RI. We examined the association between WMH severity, RI, and clinical outcomes after successful recanalization. METHODS: We retrospectively analyzed 236 patients with anterior circulation-large vessel occlusion who achieved modified Thrombolysis in Cerebral Infarction ≥2b. WMH severity was assessed using the Fazekas scale and dichotomized into absent-to-mild (score 0–3) and severe (score 4–6). RI was defined as parenchymal hematoma or malignant cerebral edema. Risk ratio (RR) was calculated, and causal mediation analysis was performed to assess the indirect effect of WMH on poor 90-day functional outcome (modified Rankin Scale of 3–6). RESULTS: Severe WMH burden was present in 60 (25.4%) cases, RI occurred in 40 (16.9%) cases, and 128 (54.2%) cases had poor outcomes. Severe WMH was associated with an increased risk of RI (RR, 3.52 [95% CI, 1.97–6.29]; P <0.001). RI was independently associated with poor outcome (RR, 1.28 [95% CI, 1.01–1.62]; P =0.042), whereas WMH alone was not. In mediation analysis, severe WMH burden was not associated with poor outcome in terms of the total effect (RR, 1.02 [95% CI, 0.78–1.31]; P =0.744), but there was a significant indirect effect of severe WMH on poor outcome through RI (RR, 1.13 [95% CI, 1.04–1.30]; P =0.004). CONCLUSIONS: Severe WMH burden increases the risk of RI, which in turn adversely affects functional outcomes despite successful recanalization. WMH assessment may aid in identifying patients at higher risk of RI and support clinical risk stratification in anterior circulation-large vessel occlusion.