Thun-How Ong

Obstructive Sleep Apnea and Cardiovascular Events After Percutaneous Coronary Intervention

Background— There is a paucity of data from large cohort studies examining the prognostic significance of obstructive sleep apnea (OSA) in patients with coronary artery disease. We hypothesized that OSA predicts subsequent major adverse cardiac and cerebrovascular events (MACCEs) in patients undergoing percutaneous coronary intervention. Methods and Results— The Sleep and Stent Study was a prospective, multicenter registry of patients successfully treated with percutaneous coronary intervention in 5 countries. Between December 2011 and April 2014, 1748 eligible patients were prospectively enrolled. The 1311 patients who completed a sleep study within 7 days of percutaneous coronary intervention formed the cohort for this analysis. Drug-eluting stents were used in 80.1% and bioresorbable vascular scaffolds in 6.3% of the patients, and OSA, defined as an apnea-hypopnea index of ≥15 events per hour, was found in 45.3%. MACCEs, a composite of cardiovascular mortality, nonfatal myocardial infarction, nonfatal stroke, and unplanned revascularization, occurred in 141 patients during the median follow-up of 1.9 years (interquartile range, 0.8 years). The crude incidence of an MACCEs was higher in the OSA than the non-OSA group (3-year estimate, 18.9% versus 14.0%; p=0.001). Multivariate Cox regression analysis indicated that OSA was a predictor of MACCEs, with an adjusted hazard ratio of 1.57 (95% confidence interval, 1.10–2.24; P=0.013), independently of age, sex, ethnicity, body mass index, diabetes mellitus, and hypertension. Conclusions— OSA is independently associated with subsequent MACCEs in patients undergoing percutaneous coronary intervention. Evaluation of therapeutic approaches to mitigate OSA-associated risk is warranted. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT01306526.

Impact of Obstructive Sleep Apnea on Cardiovascular Outcomes in Patients Treated With Percutaneous Coronary Intervention: Rationale and Design of the Sleep and Stent Study

Elucidating the effects of obstructive sleep apnea (OSA) on cardiovascular outcomes is crucial in risk assessments and therapeutic recommendations for affected individuals. The Sleep and Stent Study is a multicenter observational study investigating the relationships between OSA and cardiovascular outcomes in patients treated with percutaneous coronary intervention (PCI). Eight centers in 5 countries (Singapore, China and Hong Kong, India, Myanmar, and Brazil) are participating in the study, and the recruitment target is 1600 patients. Adult patients age 18 to 80 years who have undergone successful PCI are eligible. Recruited patients will undergo an overnight sleep study using a level‐3 portable diagnostic device before hospital discharge. The sleep tracings will be analyzed by a certified sleep technologist and audited by a sleep physician, both of whom will be blinded to other study data. The patients will be divided into 2 groups based on apnea‐hypopnea index (AHI): OSA (AHI ≥15) and non‐OSA (AHI <15) groups. The primary study endpoint of cardiovascular death, myocardial infarction, stroke, and unplanned revascularization will be compared between the OSA and non‐OSA groups at a median follow‐up of 2 years. Secondary endpoints include all‐cause mortality, target‐vessel revascularization, stent thrombosis, and hospitalization for heart failure. As of December 31, 2013, a total of 1358 patients have been recruited. Based on the complete preliminary results of the first 785 recruited patients, the prevalence of OSA was 48.3%. We expect the follow‐up for primary endpoint to be completed in late 2015; study results will be presented in 2016.

Sleep apnea is associated with new-onset atrial fibrillation after coronary artery bypass grafting

PURPOSE New-onset atrial fibrillation (AF) after coronary artery bypass grafting (CABG) remains a prevalent problem. We investigated the relationship between sleep apnea and new-onset post-CABG AF during inhospital stay. MATERIALS AND METHODS We prospectively recruited 171 patients listed for an elective CABG for an overnight sleep study. Sleep apnea was defined as apnea-hypopnea index greater than or equal to 5. RESULTS Among the 160 patients who completed the study, those in the sleep apnea group (n=128; 80%) had larger left atrial diameter (40.4±5.4 vs 38.4±6.0 mm; P=.03) and left ventricular end-diastolic dimension (52.6±7.9 vs 49.2±6.8 mm; P=.03) than those in the non-sleep apnea group. The incidence of new-onset post-CABG AF was higher for the sleep apnea than non-sleep apnea groups (24.8% vs 9.7%; P=.07). There was 1 inhospital death and 2 patients with acute renal failure requiring dialysis after CABG in the sleep apnea group. None of the patients developed inhospital stroke. Multiple logistic regression analysis showed that sleep apnea was an independent predictor of post-CABG AF (odds ratio, 4.4; 95% confidence interval, 1.1-18.1; P=.04). CONCLUSION Sleep apnea is prevalent in patients undergoing CABG. It increases the susceptibility to new-onset AF after CABG, probably related to atrial and ventricular remodeling.

Effects of Ethnicity on the Prevalence of Obstructive Sleep Apnoea in Patients with Acute Coronary Syndrome: A Pooled Analysis of the ISAACC Trial and Sleep and Stent Study

BACKGROUND Obstructive sleep apnoea (OSA) is an emerging risk factor for acute coronary syndrome (ACS). We sought to determine the effects of ethnicity on the prevalence of OSA in patients presenting with ACS who participated in an overnight sleep study. METHODS A pooled analysis using patient-level data from the ISAACC Trial and Sleep and Stent Study was performed. Using the same portable diagnostic device, OSA was defined as an apnoea-hypopnoea index of ≥15 events per hour. RESULTS A total of 1961 patients were analysed, including Spanish (53.6%, n=1050), Chinese (25.5%, n=500), Indian (12.0%, n=235), Malay (6.1%, n=119), Brazilian (1.7%, n=34) and Burmese (1.2%, n=23) populations. Significant differences in body mass index (BMI) were found among the various ethnic groups, averaging from 25.3kg/m2 for Indians and 25.4kg/m2 for Chinese to 28.6kg/m2 for Spaniards. The prevalence of OSA was highest in the Spanish (63.1%), followed by the Chinese (50.2%), Malay (47.9%), Burmese (43.5%), Brazilian (41.2%), and Indian (36.1%) patients. The estimated odds ratio of BMI on OSA was highest in the Chinese population (1.17; 95% confidence interval: 1.10-1.24), but was not significant in the Spanish, Burmese or Brazilian populations. The area under the curve (AUC) for the Asian patients (ranging from 0.6365 to 0.6692) was higher than that for the Spanish patients (0.5161). CONCLUSION There was significant ethnic variation in the prevalence of OSA in patients with ACS. The magnitude of the effect of BMI on OSA was greater in the Chinese population than in the Spanish patients.

Sleep apnoea and unscheduled re-admission in patients undergoing coronary artery bypass surgery

INTRODUCTION Although it has been recognised as a cardiovascular risk factor, data on sleep apnoea screening before coronary artery bypass grafting (CABG) are scarce. This study sought to determine the prevalence, predictors and effects of sleep apnoea on re-admission in patients undergoing CABG. METHOD We prospectively recruited 152 patients to undergo an overnight sleep study before CABG. Sleep apnoea was defined as an apnoea-hypopnoea index of ≥15 events per hour. Data on unscheduled re-admission due to cardiovascular events were collected. RESULTS Among the 138 patients who completed the sleep study, sleep apnoea was diagnosed in 69 (50%). The patients who had sleep apnoea had a lower left ventricular ejection fraction (p = 0.029), a larger left atrial diameter (p = 0.014) and a larger left ventricular end-systolic dimension (p = 0.019) than those who did not. Angiographic SYNTAX and Gensini scores were similar in patients with and without sleep apnoea. The generalised structural equation model revealed that hypertension, a high body mass index and chronic renal failure were independent predictors of sleep apnoea (p < 0.05). After an average follow-up of 6 ± 3 months, 12 patients with sleep apnoea (17.3%) and three patients without sleep apnoea (4.3%) were involved in unscheduled re-admission. Patients with sleep apnoea were almost five times more likely to have an unscheduled re-admission due to cardiovascular events (adjusted odds ratio: 4.63, 95% CI: 1.24-17.31, p = 0.023) than those without sleep apnoea. CONCLUSIONS Sleep apnoea was prevalent and predictive of unscheduled re-admissions in patients scheduled for CABG.

Optimal Body Mass Index Cut-offs for Identification of Patients with Coronary Artery Disease at High Risk of Obstructive Sleep Apnoea

BACKGROUND We sought to evaluate the relationship between Body Mass Index (BMI) and obstructive sleep apnoea (OSA) in Chinese patients hospitalised with coronary artery disease, and to determine the optimal BMI cut-off for prediction of OSA. METHODS Consecutive Chinese patients who were hospitalised with symptomatic coronary artery disease were recruited to undergo an in-hospital sleep study. RESULTS A total of 587 patients were recruited. Using cut-off for Asians, 81.2% of the cohort was overweight (BMI ≥23kg/m(2)) and 31.6% was obese (≥27kg/m(2)). A total of 59.5% was diagnosed with OSA, defined as apnoea-hypopnoea index ≥15. Body mass index, hypertension and smoking were predictors of OSA. Multiple logistic regression analysis showed that BMI remains an independent predictor of OSA (odds ratio: 1.11 [95% confidence interval: 1.06 to 1.17], p<0.001) after adjusting for smoking and hypertension. Further analysis using BMI and Apnoea-Hypopnoea Index (AHI) as continuous variables showed significant correlation between BMI and AHI (Pearsons r =0.25, P<0.001). In adjusted models, optimal BMI cut-offs to screen for OSA were 27.3kg/m(2), 23.0-23.9kg/m(2), and 20kg/m(2) for patients with neither, either, or both predictors (smoking and hypertension) respectively. The area under the curve for the adjusted and unadjusted models were similar (0.6013 vs 0.6262, p=0.118). CONCLUSIONS Body mass index represents a convenient and readily available tool for bedside identification of patients at high risk of OSA. Body mass index cut-offs to predict risks of OSA in Chinese patients with symptomatic coronary artery disease are defined in this study.