Obstructive Sleep Apnea and Cardiac Events After PCI
Does obstructive sleep apnea (OSA) status predict major adverse cardiac and cerebrovascular events post–percutaneous coronary intervention (PCI)?
The Sleep and Stent Study was a multicenter prospective nonrandomized study of patients undergoing PCI. The prespecified primary endpoint was MACCE, defined as a composite of cardiovascular mortality, nonfatal infarction, nonfatal stroke, and unexplained revascularization. Excluded were patients with known OSA on therapy or central sleep apnea, as well as patients in cardiogenic shock, unstable arrhythmias, need for balloon pump, ongoing heart failure, pregnancy, and malignancy. Patients underwent overnight home sleep study under elective conditions within a week of PCI. OSA was defined as an apnea-hypopnea index (AHI) >15 events/hour.
A total of 1,422 patients were evaluated and 1,311 (age: 58.2 ± 10.3 years; male: 85.2%; body mass index [BMI]: 25.7 ± 3.7 kg/m2; left ventricular ejection fraction [EF]: 53.4 ± 10.6%) were included for final analysis after exclusions above. OSA was diagnosed in 594 (45.3%) patients and patients were more likely to be male, have a higher BMI, and have a higher prevalence of hypertension and diabetes. Drug-eluting stents were used in 80.1% of PCI and use of bare-metal stents or other devices did not vary based on OSA status. There was no difference in stent diameter, length, or incomplete revascularization among OSA and non-OSA groups.
During a median follow-up of 1.9 years, the following patients experienced a MACCE: 24 deaths, 52 nonfatal infarction, 20 nonfatal strokes, and 92 unplanned revascularizations. The crude MACCE rate was higher in the OSA versus non-OSA group (18.9% vs. 14.0%, p = 0.001). OSA was a predictor of MACCE, with an adjusted hazard ratio of 1.57 (95% confidence interval, 1.10-2.24; p = 0.013), independent of age, sex, ethnicity, BMI, diabetes, and hypertension.
The authors concluded that OSA is independently associated with future MACCE after stenting. Improving outcomes will require studies to address this OSA-associated risk.
OSA remains underdiagnosed in cardiology practice. OSA is associated with atherosclerosis and predicts worse cardiovascular outcomes. The event rate reported here is lower than the very large Swedish angioplasty registry (NEJM 2007) likely due to more stable patients, relatively normal EF, and use of drug-eluting stents. Several issues remain unresolved: the interaction between obesity and OSA and whether it leads to different cardiovascular risk based on BMI. Second issue: whether effective treatment of OSA prior to PCI impacts outcome remains unanswered. Finally, adherence to OSA treatment is a universal problem, as evidenced by the low number of patients in the OSA group (1.3%) who remained on continuous positive airway pressure (CPAP) during the study period. Look for results from two ongoing multicenter randomized trials to address the impact of CPAP on cardiovascular outcomes.
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