Uncovering a Hidden Risk

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Undiagnosed severe sleep apnea is a major risk factor for postoperative heart complications.
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Sleep apnea is diagnosed through an overnight test that measures blood oxygen, breathing, heart rate, brain waves and eye and leg movements during sleep.

A new study recently published in The Journal of the American Medical Association (JAMA) reveals that patients with severe obstructive sleep apnea have a significantly higher risk of heart-related complications.

“We found that the risk of postoperative complications related to their heart was twice as high in patients with severe sleep apnea compared to those without sleep apnea,” says Dr. Frances Chung, a Clinician Investigator at the University Health Network’s Krembil Research Institute.

Obstructive sleep apnea causes breathing to stop and start during sleep and is the most common type of sleep apnea. It is also associated with a higher risk of death, cardiac diseases and cognitive impairment in the general population.

Dr. Chung and her team initiated the study to see whether sleep apnea poses a similar risk to surgical patients.

The study enrolled over 1,200 patients that were scheduled for major noncardiac surgery. Before the surgery, patients underwent overnight sleep testing. For 30 days after the surgery, the research team took note of any heart-related complications, such as heart attack, abnormal heart rhythm, heart failure and stroke.

The study showed that two thirds of patients had unrecognized sleep apnea and about one in ten had severe sleep apnea. Furthermore, around 30% of those with severe obstructive sleep apnea experienced a heart-related complication, while only 14% of those without sleep apnea experienced similar complications.

“The key takeaway here is that if patients have symptoms of sleep apnea, perhaps they should be treated before undergoing major surgery,” says Dr. Chung. “Further study is needed to determine how best to prevent patients with severe sleep apnea from having a higher risk of heart complications.”

Source: press release

This work was supported by the Health and Medical Research Fund (Hong Kong); the National Healthcare Group-Khoo Teck Puat Hospital; the University of Malaya; the Malaysian Society of Anaesthesiologists; the Auckland Medical Research Foundation; the University of Toronto’s Department of Anesthesia and Pain Management at University Health Network and Mount Sinai Hospital; and the Toronto General & Western Hospital Foundation.

Chan MTV, Wang CY, Seet E, Tam S, Lai HY, Chew EFF, Wu WKK, Cheng BCP, Lam CKM, Short TG, Hui DSC, Chung F. Postoperative Vascular Complications in Unrecognized Obstructive Sleep Apnea (POSA) Study Investigators. JAMA. 2019 May. doi: 10.1001/jama.2019.4783.

Dr. Frances Chung, Clincian Investigator, Krembil Research Institute.