Obstructive sleep apnea as a risk marker in coronary artery disease

Obstructive sleep apnea (OSA) is associated with a range of cardiovascular sequelae and increased cardiovascular mortality. The aim of our study was to assess the prevalence of OSA in patients with symptomatic angina and angiographically verified coronary artery disease (CAD). In addition, we analyzed the association of OSA and other coronary risk factors with CAD and myocardial infarction.

Overnight non-laboratory-monitoring-system recordings for detection of OSA was performed in 223 male patients with angiographically verified CAD and in 66 male patients with exclusion of CAD. A logistic regression analysis was performed to assess associations between risk factors and CAD and myocardial infarction.

CAD patients were found to have OSA in 30.5%, whereas OSA was found in control subjects in 19.7%. The mean apnea/hypopnea index (AHI) was significantly higher (p < 0.01) in CAD patients (9.9 +/- 11.8) than in control subjects (6.7 +/- 7.3). Body-mass-index (BMI) was significantly higher in patients with CAD and OSA than in patients with CAD without OSA (28. 1 vs. 26.7 kg/m(2); p < 0.001). No significant difference was found with regard to other risk factors and left ventricular ejection fraction (LVEF) between both groups. Hyperlipidemia (OR 2.3; CI 1. 3-3.9; p < 0.005) and OSA defined as AHI >/=20 (OR 2.0; CI 1.0-3.8, p < 0.05) were independently associated with myocardial infarction.

There is a high prevalence of OSA among patients with angiographically proven CAD. OSA of moderate severity (AHI >/=20) is independently associated with myocardial infarction. Thus, in the care of patients with CAD, particular vigilance for OSA is important.