Obstructive Sleep Apnea in Wake-Up Stroke

Koo BB, Yaggi HK, Qin L, Tobias L, Bravata DM. Obstructive Sleep Apnea in Wake-Up Stroke. [Abstract]. Stroke; A Journal of Cerebral Circulation. 2015 Apr 1; 46(4):AWP167.

Introduction: Stroke that occurs during sleep or wake-up stroke (WUS) accounts for nearly 30% of all ischemic strokes. Little is known about the characteristics of WUS and whether this stroke presentation is associated with obstructive sleep apnea (OSA). Methods: Patients with ischemic stroke were divided into WUS and non-WUS groups. Excluded were patients with iatrogenic, hemorrhagic, and dissection/aneurysmal strokes. Participants underwent polysomnography and ambulatory blood pressure monitoring. Collected data included: demographic, medical, anthropomorphic, ambulatory blood pressure, infarct location and mechanism, cholesterol, and polysomnographic (apnea-hypopnea index (AHI) and oxygen desaturation index). Results: Among 165 participants, 30.3% had WUS. There was no difference in age or race between WUS and non-WUS groups, but there was a trend for the WUS group to have more men (74.0% vs. 59.6%; p = 0.08). Cardiovascular risk factor profiles did not differ between the two groups including: history of stroke, HTN, DM, dyslipidemia, or atrial fibrillation. WUS was less likely than non-WUS to occur by cryptogenic mechanism (14.3% vs. 27.7%; p = 0.05). There was a trend for WUS to occur less in the posterior circulation (22.0% vs. 36.0%; p = 0.08). LDL cholesterol was significantly higher in the WUS group (114.5 36.3 vs. 101.4 37.6; p = 0.04). SBP did not differ between the two groups, but DBP was significantly greater in the WUS group (82.4 7.8 vs. 78.3 9.7; p = 0.03). Percentage of those with non-dipping blood pressure ( < 10% drop in MAP) did not differ between WUS and non-WUS groups (70.0% vs. 83.6%; p = 0.12; n = 103). Neither AHI (22.5 18.6 vs. 19.7 18.9; p = 0.46) nor the frequency of OSA differed between groups (81.5% vs. 79.6%; p = 0.84). There was a trend toward higher oxygen desaturation index in the WUS group (49.5 57.3 vs. 33.9 28.3 [events per hour sleep]; p = 0.13). Stroke severity did not differ according to NIH stroke scale or modified Rankin scale. Conclusion: WUS compared to non-WUS is associated with significantly higher diastolic blood pressure and LDL cholesterol. WUS does not appear more strongly associated with OSA or non-dipping BP than is non-WUS; however, there was a trend toward more frequent oxygen desaturation in WUS. Key Words:Sleep apnea Stroke