Factors Associated with Hemorrhagic Transformation in Infarctions Involving the Posterior Circulation System

Backgrounds and Purpose: Hemorrhagic transformation (HT) following stroke of the posterior circulation is a rare occurrence, and its risk factors remain relatively unknown. This study aimed at examining the rate of HT and its risk factors in patients enduring acute ischemic stroke in the territories of the vertebral, basilar, and posterior-cerebral arteries. Materials and Methods: A total of 217 consecutive patients the risk factors for ischemic stroke were recorded and comprehensive biochemical, cardiac assessments, and neuroimaging were performed. National Institutes of Health Stroke Scale (NIHSS) scores were calculated for each patient. Those with HT as documented with neuroimaging based on the European Cooperative Acute Stroke Study criteria and potential risk factors were assessed. Results: There were 217 participants with a mean age of 67.33 ± 12.44 years. Among 17 patients (7.8%) developing HT, 8 (47%) had parenchymal hematoma, and 9(53.5%) had hemorrhagic infarction. Cardioembolism was the most frequent etiological factor both in the overall group (31.0%) as well as in those with HT (41.2%). Factors that emerged as significant predictors of HT included high systolic (odds ratio [OR] 1.14; 95% confidence interval [CI] 1.08-1.20; P< .001) and diastolic blood pressure (P= .001) on the day of admission and the infarction volume of greater than or equal to 3.60 ± 3.29 cm³(OR 1.00, 95% CI 1.00-1.01; P< .001). While NIHSS scores were not significantly different on Day 1, HT patients had higher NIHSS scores at Day 10(OR 1.22; 95% CI 1.09-1.36; P< .001), and this difference was also reflected in mRS at the end of the 3 month period. Conclusion: HT is a rare complication of the infarction of the posterior circulation that is associated with increased morbidity and mortality. Identification of predictive factors for HT in patients with the acute infarction of the posterior circulation may facilitate patient selection for thrombolytic treatment.