Severe obstructive sleep apnea and outcomes following myocardial infarction

We sought to determine the effect of severe obstructive sleep apnea (OSA) on long-term outcomes after myocardial infarction. We hypothesized that severe OSA was associated with lower event-free survival rate after ST-segment elevation myocardial infarction (STEMI).

A total of 120 patients underwent an overnight sleep study during index admission for STEMI. Severe OSA was defined as apnea hypopnea index (AHI) ≥ 30, and non-severe OSA defined as AHI < 30.

Among the 105 patients who completed the study, 44 (42%) had severe OSA and 61 (58%) non-severe OSA. The median creatine kinase level and mean left ventricular systolic function were similar between the 2 groups. None of the 105 study patients had received treatments for OSA. Between 1- and 18-month follow-up, the severe OSA group incurred 1 death, 2 reinfarctions, 1 stroke, 6 unplanned target vessel revascularizations, and 1 heart failure hospitalization. In contrast, there were only 2 unplanned target vessel revascularizations in the non-severe OSA group. The incidence of major adverse events was significantly higher in the severe OSA group (15.9% versus 3.3%, adjusted hazard ratios: 5.36, 95% CI: 1.01 to 28.53, p = 0.049). Kaplan-Meier event-free survival curves showed the event-free survival rates in the severe OSA group was significantly worse than that in the non-severe OSA group (p = 0.021, log-rank test).

42% of the patients admitted with STEMI have undiagnosed severe OSA. Severe OSA carries a negative prognostic impact for this group of patients. It is associated with a lower event-free survival rate at 18-month follow-up.