Sleep-disordered breathing was associated with a higher incidence of major cardiocerebrovascular events (MACCE) in patients with acute coronary syndrome (ACS) who had undergone primary percutaneous coronary intervention (PCI), according to recent study published in the Journal of the American Heart Association.
As researchers explained, sleep-disordered breathing has been identified as an important risk factor for cardiovascular diseases, and may develop or worsen via “intermittent hypoxia, increased oxidative stress, sympathetic overactivation, endothelial dysfunction, and activated inflammatory response.” However, long-term outcomes in patients with ACS and sleep-disordered breathing have not been fully investigated.
To determine if sleep-disordered breathing was linked to poor clinical outcomes in ACS, researchers conducted overnight cardiorespiratory monitoring of 241 patients with ACS who received PCI between 2005 and 2008. This sleep study occurred approximately 1 week after the onset of ACS during hospitalization.
Apnea was defined as “cessation of airflow for ≥10 seconds, and hypopnea was defined as a 50% reduction in airflow associated with ≥4% desaturation.” PCI procedures were performed using standard techniques, and in all cases, a bare metal stent was implanted. Patients were asked to continue their aspirin regimens unless there were contraindications, and ticlopidine (200 mg/d) or clopidogrel (75 mg/d) was prescribed for at least 1 month after the procedure.
The primary end point was defined as incidence of MACCE—a composite of all-cause death, ACS recurrence, nonfatal stroke, and hospital admission for congestive heart failure.
Sleep-disordered breathing was discovered in 126 patients (52.3% of the total population), and the cumulative incidence of MACCE was significantly higher in those patients than in those without sleep-disordered breathing (21.4% vs 7.8%; P=.006). During a median follow-up of 5.6 years, 27 (21.4%) patients in the sleep-disordered breathing group had MACCE vs 9 (7.8%) patients in the non-sleep-disordered breathing group.
Researchers also conducted subgroup analyses to determine the effect modification by each risk factor on relationships between sleep-disordered breathing and MACCE using matched patients. These characteristics included hypertension (presence or absence), diabetes, dyslipidemia, smoking status, estimated glomerular filtration rate <60 ml/min per 1.73 m2, and left ventricular ejection fraction (LVEF) <50%.
On univariate Cox proportional hazards regression analysis, age, current smokers, LVEF, mean arterial oxyhemoglobin saturation (SaO2), minimum SaO2, use of beta-blockers, use of statins, and the presence of sleep-disordered breathing demonstrated values of P<.1 and were included in the multivariable analysis.
In the final multivariable stepwise regression model, sleep-disordered breathing was a significant predictor for MACCE, along with increase in age (hazard ratio [HR]: 1.04; confidence interval [CI]: 1.01-1.08; P=.007), decrease in LVEF (HR: 0.95; CI: 0.93-0.98; P=.001) and mean SaO2 (HR: 0.97; CI: 0.95-0.99; P=.015) and the absence of either beta-blocker (HR: 0.47; CI: 0.24-0.94; P=.033) or statin treatment (HR: 0.37; CI: 0.19-0.75; P=.006).
Of note is the fact that this study’s findings are consistent with previous investigations in which only short-term outcomes in patients with ACS were analyzed or only patients with stable coronary artery disease were enrolled. “To the best of our knowledge, the present study is the first to show a negative impact of SDB [sleep-disordered breathing] on long-term (>5 years) clinical outcomes other than TVR [target vessel revascularization] in ACS patients following PCI,” researchers wrote.
“Randomized clinical trials investigating whether specific treatment for coexisting SDB in ACS patients following PCI would cause an improvement in clinical outcomes will provide further information regarding the importance of detecting SDB in patients following ACS and PCI,” they concluded.
Disclosures: Dr Kasai is affiliated with a department endowed by Philips Respironics, ResMed, Teijin Home Healthacare, and Fukuda Denshi.
Mazaki T, Kasai T, Yokoi H, et al. Impact of sleep-disordered breathing on long-term outcomes in patients with acute coronary syndrome who have undergone primary percutaneous coronary intervention. J Am Heart Assoc. 2016. doi: 10.1161/JAHA.116.003270.