Vascular hyperintensities on baseline FLAIR images are associated with functional outcome in stroke patients with successful recanalization after mechanical thrombectomy.

Purpose: The purpose of this study was to assess the prognostic value of vascular hyperintensities on FLAIR images (VHF) at admission MRI in patients with acute ischemic stroke (AIS) achieving successful recanalization after mechanical thrombectomy.

Materials And Methods: Patients with AIS treated by mechanical thrombectomy following admission MRI from the single-center HIBISCUS-STROKE cohort were assessed for eligibility. VHF were categorized using a four-scale classification and were considered poor when grade < 3 (i.e., absence of distal VHF). Recanalization was considered successful when modified thrombolysis in cerebral infarction score was ≥ 2B Functional outcome was considered poor if modified Rankin scale (mRS) at three months was > 2. Univariable and multiple variable logistic regressions were performed to identify factors associated with poor functional outcome despite successful recanalization.

Results: A total of 108 patients were included. There were 65 men and 43 women with a median age of 70.5 years (interquartile range: 55.0, 81.0; age range: 22.0-93.0 years). Among them, 39 subjects (36.1%) had poor functional outcome at three months. Univariable logistic regressions indicated that poorly extended VHF (VHF grade < 3) were associated with a poor functional outcome (P = 0.008) as well as age, hypertension and diabetes, baseline National Institute of Health Stroke Scale (NIHSS) score, pre-stroke mRS, lack of intravenous thrombolysis, cerebral microangiopathy and the presence of microbleeds. Multivariable analysis confirmed that poor VHF status was independently associated with a poor functional outcome (odds ratio [OR], 4.26; 95% confidence interval [CI]: 1.55-12.99; P = 0.007) in combination with hypertension (OR, 1.25; 95% CI: 0.87-1.85; P = 0.02), baseline NIHSS score (OR, 1.09; 95% CI: 1.04-1.20; P = 0.03), pre-stroke mRS (OR, 2.05; 95% CI: 1.07-4.61; P = 0.05) and lack of intravenous thrombolysis (OR, 0.23; 95% CI: 0.08-0.61; P = 0.004).

Conclusion: Poorly extended VHF (grade <3) at admission MRI are associated with a poor functional outcome at three months despite successful recanalization by mechanical thrombectomy.