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 in patients with cardioembolic stroke studied within 6 hours of symptom onset. 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 examinations were performed on admission and at 6, 12, 24, and 48 hours. CT was performed 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 recanalization (>6 hours) occurred in 28 patients (52.8%), HT on CT scan was detected in 17 patients (32%) within the first 48 hours, Only large parenchymal hemorrhage (PH2) was significantly associated with an increase (P=0.038, Kruskal-Wallis test) in the National Institutes of Health Stroke Scale (NIHSS) score compared with the other subtypes of HT. Univariate analysis revealed that an NIHSS score of > 14 on baseline (P=0.001), proximal MCA occlusion (P=0.004), hypodensity > 33% of the MCA territory (P=0.012), and delayed recanalization occurring >6 hours of stroke onset (P=0.003) were significantly associated with HT. With a multiple logistic regression model, delayed recanalization (OR 8.9; 95% CT 2.1 to 33.3) emerged as independent predictor of HT. Conclusions-Delayed recanalization occurring >6 hours after acute cardioembolic stroke is an independent predictor of HT.