Treatment-Related Factors Associated with Hemorrhagic Transformation and Hemorrhagic Subtypes after Mechanical Thrombectomy for Acute Ischemic Stroke

BACKGROUND AND PURPOSE: Clinical studies rarely examine associations between acute ischemic stroke (AIS) treatment factors and the development of radiographic intracranial hemorrhage (ICH) that is independent of symptomatic change. Additionally, few studies perform detailed analysis of subtypes of ICH after mechanical thrombectomy (MT). The objective of this study was to examine the associations between participants and treatment-related interventions, radiographic ICH, and hemorrhagic subtypes in a large cohort of patients treated with MT for AIS. MATERIALS AND METHODS: A participant cohort across 71 global sites (n=1453) was analyzed using a multivariable imputed regression models to examine participant and treatment-related variables associated with ICH and with hemorrhagic subtypes. RESULTS: 581/1453 (40.0%) participants developed ICH at the 24-hour timepoint after MT. HI-1, HI-2, and SAH subtypes were most common. In a multivariable model, M2 occlusions (when compared with ICA occlusions) and achieving final pass eTICI of 2c or greater were protective against any ICH (OR = 0.68, CI 0.48, 0.96, p=0.03; OR = 0.79, CI 0.64, 0.97, p=0.02). M2 occlusions were significantly associated with SAH when compared to ICA occlusions (OR = 1.93, CI 1.11, 3.36, p=0.02). CONCLUSIONS: The treatment-related variables of treating a M2 occlusion and obtaining a final pass eTICI of 2c or greater were protective against ICH after adjusting for patient variables. More investigation is needed in determining the relationship between M2-segment occlusions and SAH.