Douglas Bradley
MD, FRCPC

Developing innovative ways to help people with cardiovascular disease

For a physician, few achievements can bring greater satisfaction than finding new ways to help people with serious diseases. Dr. Douglas Bradley, Senior Investigator and Director of the Sleep Research Laboratory at Toronto Rehab, has done just that.

Dr. Bradley is at the forefront of research that shows a relationship between a sleep disorder called sleep apnea and cardiovascular disease, including heart failure, hypertension and stroke.

"One of my main goals is to get the word out that sleep apnea is a risk factor for hypertension, stroke, heart failure and heart attack," says Dr. Bradley.

Sleep apnea, seen in people who snore heavily, causes a person to stop breathing repeatedly during sleep because of recurrent collapse of the throat. It can be treated with continuous positive airway pressure (CPAP), a small mask placed over the patient's nose during sleep to help improve breathing.

Doctors have known for years that people with sleep apnea are often tired and short of energy. Even worse, studies show that sleep apnea can lead to hypertension (high blood pressure) and blood clots - both causes of cardiovascular disease including stroke and heart failure. Among people who have difficult-to-control hypertension, 85 to 90% have sleep apnea, which is 10 times the prevalence in people without hypertension, according to findings by Dr. Bradley and colleagues.

In one study, Dr. Bradley and his research team showed that treating sleep apnea with CPAP can reduce blood pressure in hypertensive patients.

In a landmark study published in the New England Journal of Medicine, Dr. Bradley and colleagues found that heart function can be significantly improved in patients with congestive heart failure and obstructive sleep apnea by treating the sleep disorder with CPAP.

As well, the CPAP- treatedpatients' hearts became less enlarged, and their blood pressure and heart rate decreased - all signs of improved cardiovascular function. None of these improvements were seen in patients who did not use CPAP.

For stroke patients undergoing rehab, Dr. Bradley has found that about 70% of them have sleep apnea, compared to only five to 10 per cent of the healthy population. He has also found that sleep apnea slows down their recovery from stroke. Accordingly, it is possible that treating sleep apnea could reduce the time stroke patients need to spend in rehab, and may promote more complete recovery. "If we treat their sleep apnea, we may improve these people's functional capacity and shorten their hospitalization," says Dr. Bradley.

To learn more about using CPAP to treat stroke patients with sleep apnea, Dr. Bradley is in the midst of performinga randomized trial, comparing outcomes for patients treated with CPAP to those not treated with CPAP.

As a resident respirologist in the early 1980s, Dr. Bradley joined the staff of the very first sleep lab in Canada dedicated to breathing disorders. "I was fascinated by the whole area," he recalls. "I thought, 'how can something going on at night cause all these problems?'

"When I started, I was seeing patients with heart failure who were crippled by sleep apnea. Then I started treating them and they were coming back like new people. We opened up a whole new area."

Curriculum Vitae