Extensive White Matter Changes Predict Stroke Recurrence up to 5 Years after a First-Ever Ischemic Stroke

Abstract

Background: White matter changes (WMCs), a surrogate for small-vessel disease (SVD), have been shown to be associated with a major negative influence on cognition, mood and functioning in daily life. We aimed to investigate whether severe WMCs are a risk factor for recurrent ischemic stroke in a long-term follow-up. Methods: 320 consecutive patients admitted to hospital with a first-ever ischemic stroke were included in the study and followed up for 12 years using extensive national registers. Patients were aged between 55 and 85 years, with a mean age of 70.8 years. WMCs were rated using MRI and stratified into two grades: absent to moderate WMCs versus severe WMCs. Univariate analysis was performed using binary logistic regression analysis, Kaplan-Meier log rank analysis and life table function. To control for factors such as age, education and cardiovascular risk factors, a multivariate Cox regression proportional hazards analysis was made with forced entry. Results: At least one recurrent stroke, nonfatal or fatal, was diagnosed in 76 (23.8%) patients at 5 years and in 127 (39.7%) patients at 12 years. In univariate analysis, only advancing age was associated with WMCs. The cumulative 5-year recurrence risk was 24.5% [95% confidence interval (95% CI) 23.8–25.2] for patients with absent to moderate WMCs and 39.1% (95% CI 38.1–40.1) for patients with severe WMCs. The cumulative 12-year recurrence risk was 48.1% (95% CI 45.5–50.7) for patients with absent to moderate WMCs and 60.9% (95% CI 56.7–65.1) for patients with severe WMCs. In Cox regression proportional hazards analysis, independent predictors of recurrent stroke at 5 years were severe WMCs [hazard ratio (HR) 1.80, 95% CI 1.11–2.95], atrial fibrillation (HR 1.81, 95% CI 1.09–3.02), hypertension (HR 1.69, 95% CI 1.05–2.71) and peripheral arterial disease (HR 1.89, 95% CI 1.06–3.38). At 12 years, only increasing age remained as an independent predictor (HR 1.04, 95% CI 1.02–1.07). In receiver operating characteristic analysis, the area under the curve for severe WMCs was 0.58 (95% CI 0.51–0.65) for the prediction of stroke recurrence within 5 years. Conclusions: In our well-defined cohort of poststroke patients, the presence of severe WMCs was an indicator of stroke recurrence up to 5 years after a first-ever ischemic stroke. WMCs can be considered as an SVD marker that summarizes the effects of several classical risk factors on the small-vessel brain network and therefore can be used as a score for risk stratification of stroke recurrence. Our findings further underline the poor long-term prognosis of cerebral SVD.