Thursday, August 28, 2014

Sleep apnea makes high blood pressure difficult to treat

A study shows that sleep apnea could make a person's high blood pressure more difficult to treat.

A new study finds strong links between severe, untreated obstructive sleep apnea (OSA) and high blood pressure even for heart patients on blood pressure medication.
“The current findings suggest that severe OSA may contribute to poor blood pressure control despite aggressive medication use,” says sleep disorder specialist Harneet Walia, MD. She says the study suggests that better strategies to treat sleep apnea can improve blood pressure control. And, in turn, patients’ heart health should improve.
The study results are significant because patients were under the close care of heart specialists, Dr. Walia says. And these doctors were following national guidelines to treat cardiovascular risk.
“The results are of interest as severe levels of obstructive sleep apnea appear to be contributing to uncontrolled blood pressure.” And this leaves the patients more vulnerable to heart problems, she says.
Dr. Walia was the first author of the study, titled “Association of Severe Obstructive Sleep Apnea and Elevated Blood Pressure Despite Antihypertensive Use.” This was a part of the Heart Biomarker Evaluation in Apnea Treatment (HeartBEAT) trial.” The study appears in the American Academy of Sleep Medicine journal.

Apnea patients and poor blood pressure control

Sleep apnea is a serious sleep disorder that occurs when a person’s breathing is interrupted during sleep. People with untreated sleep apnea stop breathing repeatedly during sleep, sometimes hundreds of times during the night. Their upper airways are completely or partially blocked repeatedly during sleep.
During an apnea episode, the diaphragm and chest muscles work harder as the pressure increases to open the airway. Breathing usually resumes with a loud gasp or body jerk. These episodes can interfere with sound sleep, reduce the flow of oxygen to vital organs, and cause heart rhythm irregularities.
Of the 284 study subjects, those with serious apnea were four times more likely to have resistant elevated blood pressure – even though they were taking three or more medications, says Dr. Walia. All these patients either had or were at risk for cardiovascular disease.
Previous research has also linked obstructive sleep apnea to resistant hypertension, Dr. Walia says.
“Our study is different because these are folks who had cardiovascular disease, and who were followed by cardiologists, yet severe apnea may have contributed to suboptimal blood pressure control,” she says.
“This is an important finding from a clinical perspective because patients with poor blood pressure control taking multiple anti-hypertensive medications are particularly vulnerable to increased cardiovascular risk. Strategies to treat obstructive sleep apnea should be strongly considered because the improved control in blood pressure could potentially lead to improvement in cardiovascular morbidity and mortality,” she says.

Should you be evaluated?

Dr. Walia suggests that patients who have high blood pressure, are on anti-hypertensive medication and who have signs of obstructive sleep apnea be evaluated. Snoring, pauses in breathing during sleep, restlessness during sleep, excessive daytime sleepiness and impaired concentration are all signs of OSA, says Dr. Walia.
“It’s an important finding, especially for people who are taking multiple blood pressure medications,” she says. “They may be at risk for cardiovascular disease, anyway. Future research is definitely needed to gain a better understanding of the mechanistic pathways of this link.”
She says more studies are also needed on how sleep apnea treatment relates to blood pressure control and how it impacts people on different types of blood pressure medications.
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