Abstract WP157: Cerebral small vessel diseases in young adults with ischemic stroke receiving long-term antithrombotic therapy

Introduction: Cerebral small vessel disease (SVD) is frequently observed in older adults and represents a major cause of future stroke, but its prevalence and prognostic implications in young adults remain elusive. We aimed to determine whether SVD burden and features could identify young adults at higher risk of ischemic stroke recurrence and bleeding events during antithrombotic therapy. Methods: This was a prospective, multicenter observational study enrolling patients with cerebrovascular or cardiovascular diseases who were taking oral antithrombotic agents. This substudy focused on patients aged ≦55 years with a history of ischemic stroke. Baseline brain MRI was performed to assess SVD (white matter hyperintensities including periventricular hyperintensities [PVH] and deep subcortical white matter hyperintensities [DSWMH], cerebral microbleeds [CMBs], lacune, enlarged perivascular space, cortical superficial siderosis), and non-lacunar infarct. All images were centrally reviewed and the SVD score was assessed (range: 0–4). The outcomes were recurrent ischemic stroke, major bleeding, intracranial hemorrhage (ICH), and all-cause mortality. We assessed prospective associations of SVD with outcomes via Cox regression model adjusted for demographic and vascular risk factors. Results: Among the 5,378 patients enrolled, 428 were young adults aged ≦55 years (mean age: 46 ± 6 years; 35% women). Median SVD score was 1 (IQR: 0–1). During a median follow-up of 2 [1.80–2.03] years, 18 ischemic strokes, 4 major bleeding, and 3 ICH, corresponding to incidence rates of 2.22, 0.48, and 0.36 per 100 person-years, respectively. Of the 3 ICH, two were subdural hematomas and one was a subarachnoid hemorrhage. No all-cause deaths were observed. SVD score ≧2, strictly lobar CMBs ≥5, moderate PVH (Fazekas score ≧2) and severe DSWMH (Fazekas score ≧3) were each associated with ischemic strokes (adjusted hazard ratio: 2.96 [95%CI; 1.09–8.03], 12.5 [1.49–104.1], 3.19 [1.05–9.69], and 4.51 [1.19–17.1], respectively). Due to the low number of bleeding events, multivariable analysis was not feasible. The presence of deep CMBs increased the risk of major bleeding and ICH in univariable analysis (unadjusted hazard ratio:12.7 [1.78–90.21] and 12.5 [1.13–138.0], respectively). Conclusions: Although SVD was infrequently observed in young adults with ischemic stroke receiving antithrombotic therapy, it was associated with a higher absolute risk of recurrent ischemic stroke than of bleeding events.