Delayed Intracranial Hemorrhage after Endovascular Thrombectomy Is Associated With Poor Functional Outcomes and Elevated Systolic Blood Pressure

Abstract

Background: Hemorrhagic transformation after endovascular thrombectomy can occur either immediately (early intracranial hemorrhage [ICH]) or on follow-up imaging (delayed ICH), possibly reflecting distinct mechanisms and outcomes. This study aim to investigate the incidence and prognosis of early and delayed ICH and to examine how postprocedural blood pressure (BP) relates to delayed ICH. Methods: We analyzed consecutive patients undergoing endovascular thrombectomy (May 2019 through December 2024) who underwent post-endovascular thrombectomy dual energy computed tomography and follow-up imaging. Early ICH was defined as high attenuation on virtual noncontrast of dual energy computed tomography; delayed ICH was defined as new hemorrhage on follow-up after a negative virtual noncontrast. Hourly BP between dual energy computed tomography and follow-up was collected. Outcomes were 90-day functional independence (modified Rankin Scale score of 0-2) and 90-day death. Results: Among 268 patients, early ICH occurred in 32 (11.9%) patients, delayed ICH in 99 (36.9%), and no ICH in 137 (51.1%). Versus no ICH, delayed ICH was associated with lower odds of functional independence (adjusted odds ratio, 0.49 [95% CI, 0.25-0.94]) without a higher mortality rate (adjusted odds ratio, 1.48 [95% CI, 0.70-3.18]). Within delayed ICH, type of hemorrhagic infarction related to less functional independence, whereas type of parenchymal hematoma related to both functional dependence and death. Higher postprocedural systolic BP was associated with delayed ICH, with thresholds at mean > 150 mm Hg and peak > 166 mm Hg. Conclusions: Delayed ICH was more common than early ICH and independently associated with worse outcomes. Dual energy computed tomography facilitated temporal distinction of hemorrhage and revealed BP-related risks for delayed ICH, suggesting that delayed ICH may be preventable through optimized BP management.