Impact of White Matter Hyperintensity Volume on Prognosis After Mechanical Thrombectomy in Ischemic Stroke Patients

Background: Uncertainties remain about the impact of white matter hyperintensity (WMH) on prognosis after mechanical thrombectomy. Methods: In this retrospective study from a national prospective registry of patients with ischemic stroke due to large vessel occlusion treated with mechanical thrombectomy, we assessed WMH volume using a quantitative semi-automatized segmentation on baseline magnetic resonance imaging. We determined the association between WMH volume and the prognosis of patients with ischemic stroke presenting between 2019 and 2022. Results: Among 902 patients (mean age 70.4 years, 50% women) with a baseline magnetic resonance imaging, the median WMH volume was 2.79 (0.75-9.14) mL. In multivariate analyses, increasing WMH volume was associated with a reduced probability of favorable outcome (modified Rankin Scale score 0-2) (adjusted odds ratio per 1 log+1 increase = 0.66, 95% confidence interval 0.54-0.82) and an increased risk of mortality at 90 days (adjusted odds ratio per 1 log+1 increase = 1.53, 95% confidence interval 1.23-1.90), with the greatest risk in patients with the highest WMH volume (>11 mL) compared to those with the lowest WMH volume (<2 mL) (adjusted odds ratio = 0.38, 95% confidence interval 0.21-0.67 and adjusted odds ratio = 3.04, 95% confidence interval 1.66-5.59, respectively). There was no association between WMH volume and recanalization success and risks of any post treatment intracranial hemorrhage, symptomatic intracranial hemorrhage, and parenchymal hemorrhage. Conclusion: WMH volume is associated with increased risks of poor functional outcome and death at 90 days post mechanical thrombectomy but not with the probability of recanalization success and posttreatment intracranial hemorrhage. The use of semi-automatized tool to assess WMH volume may help better identify patients who would benefit the most from mechanical thrombectomy and predict their prognosis.