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Central Sleep Apnea and Heart Failure Mortality
The Link Between Sleep Apnea and Heart Failure
Epidemiology of Heart Failure (HF) – Nearly 5,000,000 persons or 2% of the American population suffers from heart failure. Many factors contribute to the rising incidence of heart failure, including a rising lifespan, better therapy for coronary artery disease, hypertension and obesity. Given the rise in life expectancy, it is estimated that 10% of adults over 80 years, will develop heart failure. It is estimated that the impact of heart failure on the U.S. economy is > $20 billion annually.
Epidemiology of Apnea in Heart Failure – Approximately 40% of ambulatory patients with treated, stable HF will have Cheyne-Stokes Respiration (CSR) a form of central sleep apnea (CSA) and 10% will have obstructive sleep apnea (OSA). Since both HF and Apnea increase with age, it is not unreasonable to expect that a significant proportion of the senior population will have both disorders.
Clinical Presentation – With CSA patients, snoring is usually mild or absent, and patients tend to be thinner. However, since many of the symptoms of HF and OSA are the same, the clinical presentations of OSA patients with or without HF are often indistinguishable. Therefore, physicians must maintain a high degree of clinical suspicion for coexisting diseases. The following should alert physicians for the possibility of CSA: male sex, age > 60 years, pCO2 < 38 mm Hg, the presence of atrial fibrillation or ventricular arrhythmias.
Treatment – Treatment of OSA with or without HF is similar. Achievement of ideal body weight, control of associated medical illnesses and Nasal CPAP / BiPAP or ASV. CSA associated with HF is best treated by optimizing cardiac function. Supplemental oxygen has been shown to eliminate central apneas. CPAP, BiPAP or ASV have also been shown to effectively treat CSA.
Conclusions – Both Sleep Apnea and Heart Failure are more prevalent in an increasingly aged population. Both impart a significant economic impact upon the individual patient and society as a whole. Both disorders are associated with an increase in morbidity and mortality. This begs the question “should all patients with heart failure undergo sleep studies?” The answer is clearly no. However, all patients with HF not responding to conventional therapy, or with associated signs or symptoms of OSA or CSA should have sleep studies. As physicians are likely to see an ever increasing population of patients with both HF and Apnea, a high index of clinical suspicion must be maintained and a low threshold for obtaining sleep studies should prevail.
