Sleep and heart disease

Certain sleep disorders such as obstructive sleep apnea have been linked with cardiovascular disease. This article reviews research about sleep duration and quality and coronary artery disease. I only have access to the article and the abstract. Researchers asked subjects to rate their sleep quality and the amount of sleep they get. The results showed that those who slept 5 or less hours, or 9 or more hours, had increased rates of coronary artery calcification and stiffness - both of which are early signs of coronary artery disease.

As far as I can tell, sleep quality and duration were assessed via questionnaire. There was no sleep study or other objective sleep duration measurement such as actigraphy. So it could be that some of the subjects had poor sleep quality from un-diagnosed obstructive sleep apnea, and that could account for some of the increased rates in coronary artery disease.

Obstructive sleep apnea and coronary atherosclerosis

This article discusses research about obstructive sleep apnea (OSA) and coronary artery plaques, which are blockages in the arteries supplying the heart with blood. The softer the plaque, the more dangerous it is. The results showed that more severe OSA was associated with more soft plaque formation. Also, the more severe the OSA, the greater chance of having more than one artery with plaque. This was a small study, and more research needs to be done to determine if CPAP reduces the atherosclerosis.

Obstructive Sleep Apnea and Coronary Artery Disease

In 2005, a study was undertaken to to address the impact of continuous positive airway pressure (CPAP) on patients who had undergone revascularization for coronary artery disease (CAD) and who had documented obstructive sleep apnea (OSA). The study is still ongoing, and researchers have found that the prevalence of OSA is 64% in the CAD population. Hypertension, or high blood pressure, is 58% and obesity is 28% prevalent in CAD.

Patients with CAD and OSA were older, more obese, more often male gender, and had higher incidence of hypertension, diabetes, and atrial fibrillation than those patients with CAD but not OSA.

Interestingly, the risk of CAD was the same in patients with OSA, regardless of their level of sleepiness. And the only difference in the comorbidities of sleepy versus non-sleepy OSA patients was obesity, which was more common in the sleepy OSA patients.

The researchers also studied CPAP compliance. At one year of follow-up, 70% of sleepy OSA patients with CAD were still using their CPAP compared to 60% of non-sleepy OSA patients. This makes sense, as more symptomatic OSA patients are more likely to keep using their CPAP.

The study will conclude in 2012 and the researchers are hoping to prove that treatment of OSA with CPAP will offer patients a non-pharmacologic intervention to reduce the risk of cardiovascular disease.