Sleep Apnea and Long-Term CABG Outcomes | Journal Scan

Study Questions:

Is obstructive sleep apnea (OSA) associated with higher rates of cardiovascular events following coronary artery bypass surgery (CABG)?

Methods:

Consecutive patients referred for elective CABG in a single center were evaluated with a standard sleep study in the preoperative period. CABG data were obtained. Patients were followed for short-term (30 days) and long-term cardiovascular events. Excluded were patients undergoing bypass plus some other surgery, prior diagnosis of sleep apnea, known arrhythmias, or decompensated heart failure or stroke.

Results:

A total of 100 patients were screened and 33 either withdrew, refused, or there were technical issues with the sleep study or they were lost to follow-up. Endpoint analysis was performed on 67 patients at an average of 4.5 years (range 3.2-6.1 years). Average age was 58 ± 8 years, and 75% were men. Moderate to severe OSA (apnea-hypopnea index >15) was present in 56%. Differences among OSA patients compared to no OSA included: older age, lower ejection fraction, greater use of statin, higher waist circumference, but these did not reach statistical difference. Only one patient diagnosed with OSA was treated with positive airway therapy during the trial, given lack of Public Health System providing continuous positive airway pressure for OSA. Since this patient had low adherence to treatment, he remained in the final analysis. No difference in short-term outcomes was observed. Long-term events measured on average 4.5 years were more common in patients with than without OSA. The higher rates of new revascularization, angina, and atrial fibrillation were primarily driven by the rates of revascularization (no OSA 3%; OSA 22%; p = 0.035). In a multivariate analysis, OSA was independently associated with repeat revascularization, angina, and atrial fibrillation following bypass surgery.

Conclusions:

The authors concluded that: 1) OSA is common among patients undergoing elective CABG; 2) no short-term differences in cardiovascular events were observed in patients with or without OSA; and 3) in long-term follow-up, higher events were driven by revascularization procedures in patients with OSA.

Perspective:

This was a small, single-center, observational study of CABG, which did not show any difference in death, myocardial infarction, or stroke based on OSA status. Similar to another short-term study, there was no difference in clinical outcomes. However, its impact lies in associating OSA with major adverse cardiovascular events during long-term follow-up. The study is limited in lack of Holter monitor data during the short-term follow-up to assess for differences in arrhythmias. Overall, OSA is probably not an innocent condition in patients with advanced coronary atherosclerosis, and may impact long-term prognosis. However, this will require larger studies with effective treatment in those with diagnosed OSA.

Clinical Topics: Arrhythmias and Clinical EP, Cardiac Surgery, Heart Failure and Cardiomyopathies, Invasive Cardiovascular Angiography and Intervention, Atherosclerotic Disease (CAD/PAD), Atrial Fibrillation/Supraventricular Arrhythmias, Cardiac Surgery and Arrhythmias, Cardiac Surgery and Heart Failure, Cardiac Surgery and SIHD, Interventions and Coronary Artery Disease, Sleep Apnea

Keywords: Angina Pectoris, Apnea, Atrial Fibrillation, Cardiac Surgical Procedures, Coronary Artery Bypass, Coronary Artery Disease, Follow-Up Studies, Multivariate Analysis, Myocardial Infarction, Myocardial Revascularization, Polysomnography, Preoperative Period, Sleep Apnea, Obstructive, Sleep Apnea Syndromes, Stroke, Waist Circumference


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