|Obstructive Sleep Apnea Can Cause Cardiac Changes, Study|
|Monday, 19 March 2012 09:43|
According to a new study, the improved breathing resulting from night time continuous positive airway pressure (CPAP) treatment can change health in other ways than simply reducing obstructive sleep apnea; it can also help in lowering the risk of cardiac disease. Obstructive sleep apnea is a condition resulting from interrupted breathing during sleeping at night. The results of the study are highlighted in the journal Circulation: Heart Failure.
The research team from the UK involved with this study report that their results could affect nearly 18 million individuals with obstructive sleep apnea in the United States. Dr. Justine Lachman, director of the Congestive Heart Failure Program at Winthrop-University Hospital in Mineola, N.Y., said "Sleep apnea has been frequently associated with poorly controlled blood pressure, heart failure and fatigue,"
She added "the stress of repeatedly waking up at night due to a lack of oxygen results in the heart needing to work harder. This results in abnormal thickening and relaxation of the heart's muscular tissue." The study findings suggest that moderate-to-severe obstructive sleep apnea can result in changes in cardiac shape. These changes include thickening in the cardiac wall which can disturb the pumping action of the cardiac muscle.
Meanwhile, the study indicated that a minimum of 6 months of CPAP can help in restoring the normal shape and function of the heart muscle. CPAP is a technique that uses a mask to send pressurized air (oxygen) to the lungs of people with obstructive sleep apnea.
Dr. Gregory Lip, a researcher at the University of Birmingham Center for Cardiovascular Sciences, in England, explained "To the best of our knowledge, this is the first study to provide a comprehensive assessment of left ventricular [heart] structural and functional parameters using advanced echocardiograms in otherwise healthy apnea patients," Dr. Lip notes that sleep apnea "could be crucial" in terms of resulting cardiac dysfunction "that can lead to heart failure and increased mortality if left untreated".
During their study, the research team used 2D and 3D echocardiograms and Doppler imaging on cardiac muscles of 40 individuals. All of them had a moderate-to-severe degree of obstructive sleep apnea. The study also involved 40 individuals with high blood pressure and 40 controls with no health issues. It was found that patients with obstructive sleep apnea had obvious changes in the shapes of their hearts. In regards to function, their hearts were more similar to those of chronic high blood pressure.
Dr. Lip commented saying that patients with sleep apnea "may have cardiac abnormalities that often are undetected, but will improve with CPAP," He added "Patients also need to understand that obstructive sleep apnea is not a benign disorder, but that their risk of heart problems can be easily treated with CPAP."
Dr. Lachman commented on the results of the study. She said "I have found that treatment of patients' sleep apnea has made dramatic changes in not only their quality-of-life, but also in the ability to treat associated or piggybacked conditions, such as high blood pressure and heart failure," She continued "Often, treatment of sleep apnea can also reduce the number of medications patients are required to take. So, it would make sense that treating sleep-disordered breathing would prevent the cascade of problems that results in serious heart problems."
The research team suggested that doctors should check with their patients whether they have sleep apnea when they see abnormal blood pressure or echocardiograms. The team added that people with sleep apnea were usually overweight or obese, which needs further investigation to determine the connection.
Dr. Neil Coplan, director of the division of clinical cardiology at Lenox Hill Hospital in New York City, said "The results are complicated by the fact the patients with sleep apnea had higher blood pressures than the normal control group, and the fall in blood pressure associated with CPAP therapy could be a confounding variable,"
He continued "The study is thought provoking, but there is need for a much larger study with long-term follow up to assess the clinical significance of the changes seen with therapy." It would also be interesting if a similar study was conducted using intra-oral sleep appliance therapy which is often recommended by dentists.