Stroke: What's Sleep Got to Do With It?

Abstract

Ischemic strokes most often occur between 6 AM and 12 AM after awakening from sleep but up to 30% occur during sleep. Wake-up strokes (WUS) are new focal neurological deficit(s) persisting for $ 24 hours attributable to an ischemic event present on patient awakening. Obstructive sleep apnea (OSA) is a major risk factor for WUS because it compounds the instability of the morning environment and increases the likelihood of cardiovascular events, including hypertension, atrial fibrillation, right-to-left shunts, and stroke. Circadian-driven alterations in structural, homeostatic, and serological factors also predispose to WUS. Also, WUS patients are often not considered candidates for time-dependent intravenous thrombolysis therapy because of an uncertain onset time. However, using the tissue clock (positive diffusion weighted imaging-negative fluidattenuated inversion recovery mismatch) dates the WUS as 3 to 4.5 hours old and permits consideration for intravenous thrombolysis and if needed mechanical thrombectomy. Given the high prevalence of moderate/severe OSA in stroke patients and its impact on stroke outcomes, screening with overnight pulse oximetry and home sleep apnea test is needed. Treating OSA poststroke remains challenging. Polysomnographic changes in sleep architecture following acute/subacute stroke may also impact upon stroke outcome.

Sleep and Stroke: Opening Our Eyes to Current Knowledge of a Key Relationship

“…Also, circadian misalignment has been linked to increased cardiovascular risk, including stroke [7•]. The possible influence of circadian rhythms on cardiovascular disorders was supported by the observation of a circadian rhythmicity in ischemic strokes, myocardial infarction, and sudden cardiac death, all having a peak of incidence in the morning hours [105]. The circadian system influences several cardiovascular risk factors, such as circulating catecholamine levels, blood pressure, heart rate, vagal modulation, platelet aggregability, and immune responses, thus having a possible impact on stroke risk [106].…”