OSA tied to diastolic dysfunction in heart attack patients
Presence of moderate or severe obstructive sleep apnoea (OSA) in patients who had acute myocardial infarction (AMI) was associated with more severe diastolic dysfunction, according to a study presented at the EuroEcho-Imaging 2016 Annual Meeting held recently in Leipzig, Germany.
“OSA is often under-recognized in patients with AMI,” noted Dr Nicholas Ngiam of Yong Loo Lin School of Medicine in National University of Singapore, who presented the study.
“It has been repeatedly shown that heart disease patients do not show the classic symptoms of OSA which include excessive daytime sleepiness, and patients do not have to be excessively obese to have OSA. Indeed, our studies found that most Asian OSA patients have a BMI of only 27 to 30,” said study senior author Associate Professor Ronald Lee, a senior consultant from the Department of Cardiology at National University Heart Centre Singapore.
The prospective study involved 97 survivors of AMI who successfully underwent percutaneous coronary intervention. These patients were subjected to echocardiographic imaging within 1 week of an AMI event, and a sleep study within 3 months. They were classified as controls (n=32) or OSA group (n=65) based on their OSA severity (at least moderate OSA, apnoea-hypopnoea index>15). [EuroEcho-Imaging 2016, abstract P236]
Among all participants, 65 had at least moderate OSA. These patients were more likely to have a higher body mass index (BMI, 25.2 vs 23.5 g/m2; p=0.050), a higher incidence of diabetes mellitus (46 percent vs 25 percent; p=0.045), and a lower septal E/A ratio (0.67 vs 0.83; p=0.015) compared with controls.
With increasing OSA severity, there was also increasing grade of diastolic dysfunction being observed among these patients (chi-squared, 12.67; p=0.050).
“The most important thing is that the cardiologists looking after post-AMI or post heart attack patients need to be aware of the high prevalence of OSA in this patient population,” said Lee, noting the association between OSA and diastolic dysfunction, which is a predictor of poor outcome in post-AMI patients.
“OSA represented an important comorbidity in post-AMI patients ... Strategies targeted at primary prevention and screening for OSA, together with consideration and management of OSA in patients post-AMI may prove beneficial,” suggested Ngiam.
“The current approach in Singapore [for primary prevention and screening for OSA] is one that is mainly driven by GP referral. Most hospitals in Singapore have a team of ‘sleep’ specialists who see the referred patients,” according to Lee.
“Research on OSA and heart disease has only taken off in the past 10–15 years. Thus, it is a relatively new field,” Lee added.