Association between Leukoaraiosis and Poor Outcome is not due to Reperfusion Inefficiency after Intravenous Thrombolysis

Leukoaraiosis (LA) is associated with structural and functional cerebrovascular impairment, which may compromise the capacity of ischemic tissue to maximize reperfusion after intravenous thrombolysis (IVT). We aimed to determine whether severe LA is correlated with reperfusion inefficiency, which contributes to infarct growth and poor functional outcome. We analyzed data from our consecutive acute ischemic stroke (AIS) patients who had acquired baseline and 24-h follow-up diffusion- and perfusion-weighted imaging. Reperfusion was defined as reduction of ≥70 % of hypoperfusion lesion at 24 h from baseline. Severe LA was defined as Fazekas score 2 or 3 on FLAIR images. We investigated the relationship between severity of LA and reperfusion status. Multivariate statistical analysis was carried out for modeling the independent predictors of reperfusion, infarct growth, and functional outcome. Finally, 79 patients were included, among them 30 (37.97 %) had severe LA. Reperfusion was observed in 41 (51.89 %) patients, the proportion of reperfusion was very similar in patients with and without severe LA (53.33 vs 51.02 %, p = 1.000). Large artery occlusion was the only independent unfavorable predictor for reperfusion (OR = 0.202, 95 % confidence interval, 0.060–0.673; p = 0.014). Multiple linear regression analysis revealed that severe LA was independently associated with infarct growth (standardized coefficients = 0.191, p = 0.040). Severe LA was also an independent predictor of poor outcome (mRS ≥ 3) (OR = 4.004, 95 % confidence interval, 1.267–12.656, p = 0.018) after adjusting for reperfusion and baseline severity of stroke. Severe LA was associated with infarct growth and poor outcome independent of reperfusion status, which may expand the notion that LA contributes the intrinsic vulnerability of brain tissue to acute ischemic insults. The burden of LA may not serve as an imaging indicator of reperfusion inefficiency after IVT for AIS patients.