New research has found that patients who have percutaneous coronary intervention (PCI) are at higher risk for obstructive sleep apnea (OSA). PCI, also known as angioplasty, is a procedure used to open blocked coronary arteries and restore blood flow to the heart without open-heart surgery.

One lead researcher, Luciano Drager, MD, PhD, of the University of São Paulo School of Medicine in Brazil, said: “Our findings, in a large, multicenter sample of patients, reinforce the known association between OSA and cardiovascular disease.” He added, “Nearly half of the patients in our study, who were treated with PCI for either myocardial infarctions or angina, had OSA.”

In this study, 1,305 participants had undergone PCI treatment. Most of the patients were male and came from Singapore, China and Hong Kong, India, Myanmar, and Brazil. The researchers performed an overnight sleep study on all subjects. From this test group, nearly half of the participants had moderate OSA and a little over one-fifth of the subjects had severe OSA.

For this group, the researchers administered two screening tools for OSA, and both tests offered highly differing results. From the Epworth Sleepiness Scale, only a quarter of the patients indicated a high risk for OSA. On the other test, the Berlin Questionnaire, only half of the patients were categorized as being at a higher risk for OSA. These tests suggest their unreliability. It is important to note that an estimated 80 percent of men and 93 percent of women with moderate to severe sleep apnea are undiagnosed. With such stakes involved, this study further suggests that there needs to be better tools to diagnose obstructive sleep apnea.

Besides the discrepancies in the screening tools, researchers found more connections between sleep apnea and heart disease problems. This connection has been made before, but this study further confirms this relationship. Dr. Drager added: “Earlier studies have shown strong relationships between sleep apnea and a number of cardiovascular conditions, including high blood pressure, arrhythmia, stroke and heart failure. Our study supports this strong association between OSA and heart disease and also suggests that the methods used to screen for OSA in patients with cardiovascular disease need to be improved.”

The importance of this study evaluates whether OSA contributes to the risk of several heart problems in patients who have undergone successful PCI. Dr. Drager’s research concludes that OSA does contribute to the risks of heart disease, especially for those who have had PCI treatment. He has also discovered that screening tools for OSA need to be better developed so that the highly undiagnosed population with obstructive sleep apnea can get early treatment.

 also discovered that screening tools for OSA need to be better developed so that the highly undiagnosed population with obstructive sleep apnea can get early treatment.