CHICAGO—Obstructive sleep apnea is associated with subclinical coronary artery disease independent of the traditional cardiovascular risk factors, Dr. Dan Sorajja reported at the annual scientific sessions of the American Heart Association.
Moreover, the severity of subclinical CAD as reflected by the extent of coronary artery calcium (CAC) on electron beam CT increases with obstructive sleep apnea severity. For this reason, the presence and severity of obstructive sleep apnea ought to be incorporated into CAD risk stratification and preventive cardiology efforts, according to Dr. Sorajja of the Mayo Clinic, Rochester, Minn.
He reported on 202 consecutive patients with no history of CAD who underwent electron beam CT within 3 years of polysomnography at the Mayo Clinic. They were a median of 50 years old, with a mean body mass index of 33 kg/m
In a multivariate analysis, the adjusted odds ratio for CAC increased in stepwise fashion with each increasing quartile of obstructive sleep apnea severity as determined by the apnea-hypopnea index (AHI). The prevalence of CAD was 2.1-fold greater in patients in the second obstructive sleep apnea severity quartile, with an AHI of 5–13, than in those in the lowest quartile. The CAC prevalence was 2.4-fold greater among patients in the third quartile, with an AHI of 14–32, than in the first. And in individuals in the top quartile, where the mean AHI was 63, the prevalence of CAC was 3.3-fold greater than in the first quartile.
The chief limitation of a cross-sectional study such as this one is the potential for selection bias, he conceded.
Obstructive sleep apnea is a common medical condition, with an estimated prevalence of 4%–9% among middle-aged adults. The condition has previously been shown to be a cause of hypertension, Dr. Sorajja noted.