Sleep apnea plays dual role in stroke

Obstructive sleep apnea, a disorder where the flow of air to the brain pauses or decreases during sleep, is both a risk factor for stroke and a complication following stroke, according to the Canadian Best Practice Recommendations for Stroke Care.

Among the general population sleep apnea increases the likelihood of having a stroke, even after controlling for other stroke risk factors, such as high blood pressure and diabetes, researchers say.

At absolute minimum, four per cent of men and two per cent of women have serious sleep apnea, says Dr. Brian Murray, an associate professor of neurology and sleep medicine at the University of Toronto. Dr. Murray adds that clinically significant forms of the disorder affect more than 10 per cent of the population.

"There are ways to prevent sleep apnea from occurring," says Dr. Murray. "Keep your body weight low as obesity is a major contributor to sleep apnea; avoid medications and substances that relax the airways and cause snoring, such as sedatives and alcohol; and sleeping on your side can minimize sleep disordered breathing."

Signs of sleep apnea include significant snoring, pauses in breathing during sleep and daytime fatigue despite adequate sleep time. If any of these symptoms are present, says Dr. Murray, you should be evaluated by your doctor to determine next steps.

Obstructive sleep apnea is common after stroke. According to the updated best practice recommendations, at least 60 per cent of stroke patients experience sleep apnea. The new recommendations call for more screening of stroke patients who say they experience snoring, fragmented sleep or fatigue. Although, in many cases with stroke patients, daytime fatigue does not appear as a symptom, says Dr. Murray.

It is crucial for stroke patients to be screened for sleep apnea because untreated sleep apnea increases the chances of a second stroke and small studies have found that stroke patients with sleep apnea tended to have worse rehabilitation outcomes, says Dr. Murray.

The best practices also describe "higher rates of mortality and other complications in patients with stroke and untreated obstructive sleep apnea."

"This innovative Canadian research continues to show that there is more to learn about rehabilitation and recovery following stroke," says Ian Joiner, director of stroke for the Heart and Stroke Foundation. "Reflecting these advances in tools such as the Best Practices Recommendations for Stroke Care will help improve outcomes for Canadians."

The new recommendations are the fourth update to the Canadian Best Practice Recommendations for Stroke Care and this is the first time the recommendations have included a section on sleep apnea. The best practices were first released in 2006 to improve stroke care for Canadians living with stroke and future stroke patients. They are updated every two years.

"The new recommendations take stroke care a step further," says Dr. Michael Hill, Canadian Stroke Congress Co-Chair. "Stroke care is not only about giving the best possible treatment to patients. It is also about preventing new and recurrent strokes."

The Canadian Stroke Congress is a joint initiative of the Canadian Stroke Network, Heart and Stroke Foundation of Canada and the Canadian Stroke Consortium.