Timing of spontaneous recanalization and risk of hemorrhagic transformation in acute cardioembolic stroke

Background and Purpose-The relationship between reperfusion and hemorrhagic transformation (HT) remains uncertain. Therefore, we aimed to clarify the relationship between the time course of recanalization and the risk of HT i n patients with cardioembolic stroke studied within 6 hours of symptom onse t. Methods-Fifty-three patients with atrial fibrillation and nonlacunar stroke in the middle cerebral artery (MCA) territory admitted within the first 6 hours after symptom onset were prospectively studied. Serial TCD examinatio ns were performed on admission and at 6, 12, 24, and 48 hours. CT was perfo rmed within 6 hours after stroke onset and again at 36 to 48 hours. Results-Proximal and distal MCA occlusions were detected in 32 patients (60 .4%) and 18 patients (34%), respectively. Early spontaneous recanalization occurring within 6 hours was identified in 10 patients (18.8%). Delayed rec analization (>6 hours) occurred in 28 patients (52.8%), HT on CT scan was d etected in 17 patients (32%) within the first 48 hours, Only large parenchy mal hemorrhage (PH2) was significantly associated with an increase (P=0.038 , Kruskal-Wallis test) in the National Institutes of Health Stroke Scale (N IHSS) score compared with the other subtypes of HT. Univariate analysis rev ealed that an NIHSS score of > 14 on baseline (P=0.001), proximal MCA occlu sion (P=0.004), hypodensity > 33% of the MCA territory (P=0.012), and delay ed recanalization occurring >6 hours of stroke onset (P=0.003) were signifi cantly associated with HT. With a multiple logistic regression model, delay ed recanalization (OR 8.9; 95% CT 2.1 to 33.3) emerged as independent predi ctor of HT. Conclusions-Delayed recanalization occurring >6 hours after acute cardioemb olic stroke is an independent predictor of HT.