Background and Purpose-Wake-up stroke (WUS) represents a quarter of all ischemic strokes and may be a specific subgroup. Nocturnal desaturation secondary to sleep-disordered breathing is an independent risk factor for stroke, but the association between nocturnal desaturation and WUS remains unclear. We investigated the relationship between nocturnal desaturation using oxygen desaturation index and WUS in patients with acute stroke in the stroke unit. Methods-A total of 298 patients admitted for acute ischemic stroke to the stroke unit between July 2013 and May 2015 were enrolled. The oxygen desaturation index was calculated using pulse oximetry data sampled every 1 minute during 9 hours on the first night (10:00 PM-7:00 AM) of the stroke unit admission, and nocturnal desaturation was defined as an oxygen desaturation index of 5 at least per hour. We compared the clinical characteristics and nocturnal desaturations between patients with and without WUS. Results-Among all patients (age, 67.7±12.6 years; male, 54.4%), 26.5% patients had WUS. The proportion of nocturnal desaturation was significantly greater in patients admitted with WUS (29.1% versus 12.3%, P=0.001). The age, sex, risk factors except for hyperlipidemia, stroke severity, and stroke mechanisms were similar between the 2 groups. After adjustment for covariates, it was found that nocturnal desaturation was significantly more common in the WUS group (odds ratio, 3.25; 95% confidence interval, 1.63-6.46). Conclusions-Nocturnal desaturation was more frequently observed in patients admitted with WUS during the first night in the stroke unit. This suggests that nocturnal desaturation is a possible modifiable risk factor for the occurrence of WUS.
Baseline and Clinical AssessmentBaseline characteristics, including demographic data (age and sex) and vascular risk factors (hypertension, diabetes mellitus, hyperlipidemia, smoking history [current or past regular smoking], body mass index [BMI], and a past history of stroke/transient ischemic attack) were evaluated. Hypertension was defined as a history of antihypertensive treatment, a systolic blood pressure ≥140 mm Hg, or a diastolic blood pressure ≥90 mm Hg. 14 Hyperlipidemia was defined as a history of lipid-lowering medication, a serum total cholesterol level of >240 mg/dL, or a serum level of low-density lipoprotein cholesterol >160 mg/dL.15 Diabetes mellitus was defined as a hemoglobin A1C level of ≥6.5%, fasting blood glucose level of ≥7.0 mmol/L, nonfasting blood glucose level of ≥11.1 mmol/L, or the use of insulin or oral hypoglycemic drugs. 16 All of the patients were initially evaluated for stroke severity based on the National Institutes of Health Stroke Scale (NIHSS) neurological examination at SU admission. Ischemic strokes were categorized as large-artery atherosclerosis (LAA), small-vessel occlusion, cardioembolism, other determined, and undetermined based on the Trial of Org 10172 in Acute Stroke Treatment criteria.
17The ischemic lesion locations were divided into anterior circulation (ante...