A study published this month in the New England Journal of Medicine tested the effects of CPAP therapy on heart disease.
Positive Airway Pressure devices, called PAP, deliver pressurized ambient air through a delivery system (tubing and mask), to eliminate apnea events during sleep. PAP, including CPAP, BIPAP, Auto-PAP, and ASV-PAP, is the most effective treatment for obstructive sleep apnea and can potentially improve the patient’s sleep overnight, dramatically improving the quality of life for individuals afflicted with sleep apnea (learn more about PAP here).
The Sleep Apnea Cardiovascular Endpoints (SAVE) trial looked at patients with a history of coronary artery disease or cerebrovascular disease AND moderate to severe obstructive sleep apnea. Participants were randomly assigned to received CPAP plus usual care or usual care alone.
The results of the study showed that use of CPAP did not result in a lower rate of cardiovascular issues (for this study, they looked for deaths from cardiovascular causes, myocardial infarction, stroke, or hospitalization for unstable angina, heart failure, or transient ischemic attack).
Does this mean that CPAP is not an effective treatment?
A subsequent editorial in the New England Journal of Medicine by Drs. Babak Mokhlesi and Najib T. Ayas point to several issues with the trial.
(1) Were the results negative because sleep apnea doesn’t have clinically significant adverse cardiovascular effects or because the patients did not use CPAP long enough each night to get any benefit?
Participants in the trial used CPAP only an average of 3.3 hours per night. Is this enough time to prevent heart risks?
(2) Does the timing of CPAP use affect the results?
CPAP used in the beginning of the night may be less effective than when used later in the night when more REM sleep occurs. Apnea and hypopnea are more likely to happen in REM sleep and events that occur during REM sleep have a stronger association with hypertension.
Sleep apnea has an undisputed effect on the heart
Research over the past two decades has built a case for sleep apnea’s role in worsening cardiovascular health. Experts are still working to discover exactly how sleep apnea affects the heart, but the evidence is strong says Said Mostafavi, M.D., the Chief Medical Officer for our company, Advanced Sleep Medicine Services, Inc., a pulmonologist and sleep specialist.
He uses every opportunity to inform his colleagues about the connection between sleep apnea and heart issues. “If you have a patient with obstructive sleep apnea, they could be at risk,” he says. He stresses that if symptoms suggest sleep apnea, a person faces more than poor quality sleep. There may be life threatening cardiovascular and cerebrovascular complications. “I think the cardiovascular risk is extremely common and extremely important, not to mention diagnosable and treatable.”
This recent study only measured deaths from cardiovascular causes, myocardial infarction, stroke, or hospitalization for unstable angina, heart failure, or transient ischemic attack after treatment with CPAP for a short period of time. Other studies have looked the correlation between heart issues and severe sleep apnea as well as the long-term effects of CPAP. Read more about the effect of sleep apnea on the heart in our blog post here.
What does this mean for CPAP users?
I asked Dr. Mostafavi if this new research changes anything for his patients. “Knowing that research in this area is ongoing, I still recommend that all of my patients with OSA in presence of cerebro/cardiovascular disease use their PAP device since it reduces the afterload; therefore, reducing the left ventricular workload and the assumption that reducing sympathetic tone would prevent vasoconstriction (opening up the arteries).”
Additionally, despite the negative effects on the heart-related measures shown in this study, CPAP had a significant beneficial effect on quality of life, mood, daytime sleepiness and work productivity of the study participants. These benefits alone are more than enough reason for those diagnosed with OSA to use CPAP.
Drs. Mokhelsi and Ayas still believe that for symptomatic patients with obstructive sleep apnea, CPAP should be offered. For patients who also have severe hypoxemia, regardless of symptoms, CPAP should also be offered (these patients were excluded from the SAVE trial).
They acknowledge that further research is needed, but that on the basis of these results, use of CPAP only to reduce future cardiovascular events cannot be recommended. Additionally, new treatments for sleep apnea that can increase adherence to therapy are greatly needed.
Are you concerned that you may have a sleep disorder like sleep apnea? If so, talk to your doctor. Would you like a consultation with a sleep specialist?
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