Background Predictors and impact of hemorrhagic transformation (HT) after thrombectomy remain to be elucidated.

Objective To investigate the independent predictors and impact of each hemorrhagic infarction (HI) and parenchymal hematoma (PH) after thrombectomy in patients with acute stroke due to intracranial large vessel occlusion (LVO).

Materials and methods We retrospectively reviewed data from 400 patients with acute LVO who underwent thrombectomy. Logistic regression analyses were performed to determine independent predictors of HI and PH on post-treatment CT scans. Associations between HT and poor outcome (modified Rankin Scalescore ≥3) at 90 days were analyzed.

Results HT was observed in 98 patients (62 HIs (15.5%) and 36 PHs (9%)). Independent predictors of HI were male sex, atrial fibrillation, and time from symptom onset to groin puncture. Hyperlipidemia (OR=0.221, 95% CI 0.064 to 0.767, P=0.017) and successful reperfusion (OR=0.246, 95% CI 0.093 to 0.651, P=0.005) were independently associated with a lower chance of PH, while hypertension (OR=2.260, 95% CI 1.014 to 5.035, P=0.046) and longer procedure duration (OR=1.046, 95% CI 1.016 to 1.077, P=0.003) were independently associated with a higher chance of PH. Only PH (OR=10.154, 95% CI 3.260 to 31.632, P<0.001) was an independent predictor of poor outcome.

Conclusions PH is independently associated with poor outcome, whereas HI does not predict outcome after thrombectomy in patients with acute LVO. Our findings suggest that rapid and successful reperfusion is essential to prevent PH in patients undergoing thrombectomy for acute LVO. In addition, our study suggests that hyperlipidemia is associated with a lower risk of PH in such patients.