2D Parametric Parenchymal Blood Flow as a Predictor of the Hemorrhagic Events after Endovascular Treatment of Acute Ischemic Stroke: A Single-Center Retrospective Study.

Background and purpose: Intracranial hemorrhage (ICH) is one of the major adverse events related to the endovascular management of acute ischemic stroke. It is important to evaluate the risk of ICH as it may result in clinical deterioration of the patients. Development of tools which can predict the risk of ICH after thrombectomy can reduce the procedure-related morbidity and mortality. 2D parenchymal blood flow could potentially act as an indicator for ICH.

Methods: 2D parenchymal blood flow was used to evaluate pre- and postthrombectomy digital subtraction angiography series of patients with acute ischemic stroke in the anterior circulation. A recently developed software allows the separation of the vascular filling and parenchymal blush signals using band-pass and band-reject filtering to allow for greater visibility of the parenchyma offering a better visual indicator of the effect of treatment. The "wash-in rate" was selected as the parameter of interest to predict ICH.

Results: According to the presence or absence of signs of intracranial parenchymal hemorrhage in the follow-up dual-energy CT brain scans, the patients were classified into a hemorrhagic and nonhemorrhagic group (15 patients each). The only significant difference between the groups is the calculated wash-in rate after thrombectomy (p = 0.024). The cutoff value of the wash-in rate after thrombectomy was suggested to be 11,925.0, with 60% sensitivity to predict the hemorrhage and 93.3% specificity.

Conclusions: Elevated parametric parenchymal blood flow wash-in rates after thrombectomy may be associated with increased risk of hemorrhagic events.