Introduction/Hypothesis: Stroke onset during sleep is common and sleep related pathologies have been associated with increased stroke risk. Based on available preliminary data, we tested the hypothesis that stroke during sleep is associated with small vessel disease (SVD).
Methods: Prospectively collected data from patients consecutively enrolled after an intracerebral hemorrhage (ICH) related to SVD or after an ischemic stroke (IS) were analyzed. Symptom onset was recorded in relation to sleep vs. awake. Etiology of ICH was coded as cerebral amyloid angiopathy (CAA, per Boston criteria) and hypertensive deep ICH (HTN-ICH). The IS cohort was characterized based on the Causative Classification of Stroke system (5 subtype CCS). We compared frequencies of stroke onset during sleep between the SVD-related ICH and IS cohorts. Event rates, proportions of strokes during sleep and its associations (etiology, risk factors and stroke characteristics) were also analyzed within each cohort.
Results: We analyzed 1,038 ICH (mean age: 72.5y +/- 13.0y, 45.4% female) and 1,812 IS patients (mean age: 67.9y +/- 15.9y, 46.4% female). Stroke while asleep was significantly more common among ICH patients (n=282, 26.6%) when compared to IS (n=363, 20.0%, p<0.001). This association between SVD-related ICH and stroke during sleep remained significant after controlling for age, gender and other risk factors (p<0.001). CAA-related ICH and small artery occlusion (SAA) related IS were etiologic subtypes more common among patients who had a stroke during sleep within their respective cohorts (asleep vs awake for CAA within ICH: 57.2% vs. 48.0%, p=0.008 and for SAA within IS: 19.3% vs. 9.1%, p<0.001). CAA and SAA etiologic types remained independent predictors of ICH and IS during sleep in respective multivariate models including other clinical features and risk factors (p=0.019 and p=0.011).
Conclusions: Stroke during sleep was strongly associated with SVD-related ICH when compared to all IS. CAA within ICH group and SAA etiology within IS cohort were related to stroke during sleep in univariate and multivariate models. Presence of SVD can interact with sleep pathologies and/or sleep related hemodynamic changes to cause ischemic and hemorrhagic stroke.