Feature Article

Portable Cardiopulmonary Screening Could Help Diagnose Sleep Apnea in Patients With Acute Ischemic Stroke

BOSTON—A portable cardiopulmonary screening method could be a reliable tool for the early diagnosis of sleep apnea in patients with acute ischemic stroke, according to research presented at the 26th Annual Meeting of the Associated Professional Sleep Societies.

The technique provided similar diagnostic information to that of polysomnography, said Oleg Chernyshev, MD, Assistant Professor of Neurology at the University of Texas in Houston, and Clinical Assistant Professor of Neurology at the Louisiana State University Health Sciences Center, Shreveport, LA.

Dr. Chernyshev and his colleagues performed simultaneous bedside level-three cardiopulmonary and polysomnography studies of 21 patients with acute ischemic stroke. All patients were observed within 72 hours of stroke onset. The researchers compared the accuracy of cardiopulmonary testing with that of polysomnography using various statistical analyses.

Fifty-eight percent of the study population was African American, and 52% were male. The population’s mean age was 61, mean neck circumference was 16.8 inches, and mean BMI was 30. On admission, patients had a mean NIH Stroke Scale score of 6 and a mean modified Rankin Scale score of 3.

Approximately 67% of patients had either obstructive sleep apnea or central sleep apnea. About 48% of patients had obstructive sleep apnea, and 19% had central sleep apnea. The only significant differences between patients with and without sleep apnea were neck circumference and BMI, Dr. Chernyshev noted. Patients with obstructive sleep apnea had a mean neck circumference of 17 inches, compared with 15 inches for patients without obstructive sleep apnea. In addition, patients with obstructive sleep apnea had a mean BMI of 33, compared with 23 for patients without obstructive sleep apnea.

Cardiopulmonary testing provided an apnea–hypopnea index (AHI) of 19.8, compared with 22 for polysomnography. The difference between the two measurements was not significant, according to Dr. Chernyshev.

For identifying patients with an AHI of 5 or greater, as measured by polysomnography, cardiopulmonary screening had 100% sensitivity, 85.7% specificity, 93% positive predictive value (PPV), and 100% negative predictive value (NPV). For identifying patients with an AHI of 15 or greater, as measured by polysomnography, cardiopulmonary screening had 100% sensitivity, 83.3% specificity, 81.8% PPV, and 100% NPV. “With AHI values higher than 30, sensitivity dropped,” and specificity and PPV were 100%, said Dr. Chernyshev. The Bland–Altman plot showed good overall diagnostic agreement between polysomnography and cardiopulmonary screening.

—Erik Greb

 

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