Impact of Leukoaraiosis Severity on the Association of Outcomes of Mechanical Thrombectomy for Acute Ischemic Stroke: a Systematic Review and a Meta-Analysis

Background Leukoaraiosis (LA) severity is associated with poor outcome after mechanical thrombectomy (MT) for acute ischemic stroke (AIS) caused by large vessel occlusion. This meta-analysis aimed to assess the association of LA severity with AIS-related risk factors and outcomes of MT. Methods PubMed, Web of Science, EMBASE, and Cochrane Collaboration Database was searched for studies on MT for AIS with LA. We conducted a random-effects meta-analysis for the prevalence of stroke risk factors and the MT outcome in the absent to moderate LA and severe LA groups. Results We included seven cohort studies involving 1294 participants (1019 with absent to moderate LA and 275 with severe LA). The absent to moderate LA group had a significantly lower prevalence of coronary artery disease (odds ratio [OR] 0.43; 95% CI 0.29-0.66), atrial fibrillation (OR, 0.26; 95% CI 0.17-0.38), hypertension (OR, 0.39; 95% CI 0.24-0.61), and ischemic stroke (OR, 0.27; 95% CI 0.15-0.50) than the severe LA group. There were no significant between-group differences in symptom onset to recanalization time (364.4 versus 356.2 min, mean difference 19.4; 95% CI - 28.3 to 67.2), final recanalization rate (modified thrombolysis in cerebral infarction score of 2b/3; OR, 0.87; 95% CI 0.55-1.38), and symptomatic intracranial hemorrhage (OR, 0.62; 95% CI 0.34-1.11). The absent to moderate LA group had a higher good functional outcome (modified Rankin Scale score of 0-2 at 90 days; OR, 4.55; 95% CI 3.20-6.47) and a lower mortality rate (179/1019 vs 108/275; OR, 0.28; 95% CI 0.20-0.39). Conclusion There are unique differences in the characteristics of risk factors and clinical outcomes of ischemic stroke across patients with LA of different severity. Patients with severe LA are more likely to be associated with risk factors for cerebrovascular disease and have a poor post-MT outcome.