Angiographic Blush after Mechanical Thrombectomy is Associated with Hemorrhagic Transformation of Ischemic Stroke

Abstract

Background and Purpose

Risk factors for hemorrhagic transformation of ischemic stroke after mechanical thrombectomy (MT) are not well established. We conducted a study to determine if prominent angiographic cerebral vascularity following recanalization with thrombectomy (angiographic blush) is associated with hemorrhagic transformation.

Methods

Using the Cornell AcutE Stroke Academic Registry, we identified stroke patients who had thrombectomy and achieved recanalization of anterior circulation large-vessel occlusion between 2012 and 2015. The exposure variable was presence of angiographic blush after recanalization, defined as capillary blush with or without early venous drainage. The primary outcome was volume of hemorrhagic transformation on brain imaging after thrombectomy, as determined by semiautomated volumetric analysis on computed tomography or magnetic resonance imaging among those adjudicated to have hemorrhagic conversion by neuroradiology investigators blinded to angiography results. Using a doubly robust estimator with propensity scores and outcome regression adjusting for demographics and known risk factors for hemorrhagic transformation, we evaluated whether angiographic blush after recanalization is associated with an increased volume of hemorrhagic transformation.

Results

Among 48 eligible patients, 31 (64.6%) had angiographic blush and 26 (54.2%) had radiographic hemorrhagic transformation (mean volume, 7.6 ml). Patients with angiographic blush averaged lower thrombolysis in cerebral infarction scores and more often received intravenous thrombolysis. In adjusted analysis, angiographic blush was associated with an increased volume of hemorrhagic transformation: mean volume, 10.3ml (95% CI, 3.7-16.9 ml) with blush versus 1.8ml (95% Confidence Interval (CII = Confidence Interval), 0.1-3.4 ml) without (P = .01).

Conclusions

Presence of angiographic blush after MT was independently associated with the volume of hemorrhagic transformation.

Introduction

Randomized trials have established mechanical thrombectomy (MT) with stent-retrievers as the standard treatment for acute ischemic stroke from proximal large-vessel cerebral artery occlusion.¹ However, these procedures are not without risk, which occurs in about 5%-6% of patients following treatment.2, 3 Symptomatic intracranial hemorrhage after stroke is associated with worse long-term functional outcomes and increased mortality.4, 5 Unlike with intravenous thrombolysis, predictors of hemorrhagic transformation after MT are not well established. Some possible risk factors include history of diabetes or atrial fibrillation, higher degree of initial stroke severity, use of intravenous thrombolysis, delays in arterial puncture, lower pretreatment Alberta Stroke Program Early CT Score (ASPECTS) scores, and incomplete recanalization.6, 7, 8, 9 Apart from clinical information and reperfusion grading schemes, there is limited data on angiographic markers of hemorrhagic transformation.

Prominent brain vascularity in the form of capillary blush with or without arteriovenous shunting and early venous drainage (so called angiographic blush) can be seen on angiography after acute recanalization of cerebral artery occlusion with MT. The clinical relevance of angiographic blush is uncertain but some data suggest that it is a biomarker for endothelial damage and blood brain barrier disruption, and that it might predict hemorrhagic transformation after recanalization therapy, as well as resultant poor outcomes.10, 11, 12, 13 Identifying a novel angiographic marker might aid in preventing hemorrhagic transformation and clinical deterioration in susceptible patients through various means, including aggressive postMT blood pressure control. In this study, we investigated the association between angiographic blush after MT and the volume of postprocedural hemorrhagic transformation. Our hypothesis was that angiographic blush would be associated with an increased volume of hemorrhagic transformation independent of confounding factors.