The prevalence of obstructive sleep apnea appears to be greater among men with a history of ischemic heart disease [1]. The existence of a causal link between obstructive sleep apnea and myocardial ischemia (in men with preexisting coronary artery disease) or between obstructive sleep apnea and the development of coronary atherosclerosis has not been established; the alternative is that obstructive sleep apnea is a proxy for an as-yet-unknown causal factor. Nevertheless, as Dr. Ortega and colleagues point out, it is reasonable to assume that a man with coexisting sleep apnea syndrome and coronary artery disease might be at a higher risk for perioperative myocardial infarction with noncardiac surgery than a man with only coronary artery disease. This is because recovery room respiratory depression induced by analgesics and residual anesthetics might exacerbate the gas exchange and the hemodynamic aberrations associated with sleep apnea.

We cannot provide data on the prevalence of obstructive sleep apnea among the 1487 men in our study. Our preoperative interview did not include screening questions to detect undiagnosed sleep apnea. However, the letter by Dr. Ortega and colleagues prompted us to go back and examine the records of the men who had perioperative myocardial infarction in our study. Preoperatively, none was known to have sleep apnea, but we found that 1 patient, a diabetic patient with heart failure, was diagnosed with sleep apnea 7 days after his below-knee amputation. This man was 5'8" tall and weighed 240 pounds. He was referred for polysomnography by his surgeons, who noted that he had apneic episodes in the recovery room. His infarction was diagnosed on postoperative day 5; his only symptom was lethargy.

We agree with Dr. Ortega and colleagues that screening questions about snoring and daytime hypersomnolence should be added to the preoperative medical evaluation, especially in obese patients. Women should also be questioned, because they have a higher prevalence of sleep apnea than previously recognized. Young and colleagues [2] found the male:female ratio for sleep apnea to be 3:1 instead of 8:1 or 10:1 as was previously believed. More data are needed to determine the extent to which sleep apnea increases perioperative mortality and morbidity.