Hemorrhagic transformation following a malignant middle cerebral artery infarction

Objective: This study aimed to determine the frequency of hemorrhagic transformation (HT) and evaluate its impact on the clinical course and outcomes of patients with malignant middle cerebral artery (MCA) infarction. Methods: A retrospective review was conducted of 74 patients with malignant MCA infarction, aged 44 to 92 years (mean age 71.5±2.0 years; 54.0% female), admitted between 2017 and 2025. Conservative therapy was administered to 77.0% of patients, while 22.9% underwent decompressive hemicraniectomy. All cases of HT were assessed using computed tomography according to the ECASS I classification. Results: In the study cohort, 15% of patients received intravenous thrombolysis (IVT). Significantly, among this group, 100% developed HT as a complication. Hemorrhagic infarction (HI) occurred in 81.8% of these cases and was asymptomatic, not worsening the clinical condition or neurological deficits. Parenchymal hemorrhage (PH) occurred in 18.2% and was associated with clinical deterioration and fatal outcomes. In patients not receiving IVT, HT was observed in 66.6% of cases: HI type 1 occurred in 33.3%, HI type 2 in 47.6%, and PH type 1 in 19.0%. No cases of PH type 2 were reported. Conclusions: HT is highly prevalent in malignant MCA infarction, regardless of IVT administration, with the majority of cases asymptomatic. Consequently, these findings suggest that asymptomatic HT may represent a natural progression of large infarcts rather than a treatment complication. The results underscore the need for early diagnostic markers and improved management strategies for HT in malignant MCA infarction.