Central sleep apnea(CSA) and Cheyne Stokes respirations are commonly found in patients with severe congestive heart failure. Prior studies have estimated prevalence to be 11- 43%. Frequency of sleep disordered breathing is associated with severity of cardiac dysfunction and is infrequent in patients with LVEF>40%. Some studies show that heart failure is found to improve with the treatment of sleep apnea. Other stuides have shown that after heart transplantation, those patients with CSA may develop obstructive sleep apnea (OSA), which may be due to central sleep apnea masking OSA in the pre-transplant period or may be secondary to other post transplant factors. Our study was to determine how prevalent sleep apnea is in patients that are listed for heart transplant in this era of ace inhibitors and beta blockers.
From May 2008 to July 2008, all patients being listed for cardiac transplant at our facility were approached for baseline sleep study. In these patients, apnea-hypopnea index (AHI) and central apnea hypopnea index were analyzed.
Overall, 10/13 patients (76%) were found to have OSA, 2/13 found to have CSA, and the remaining 1 patient had no sleep breathing disorder. The risk of OSA did not vary among patients with varying BMI, neck circumference or Mallampati score.
We have found a strikingly increased incidence of OSA among heart failure patients that have been listed for transplant. We think this may be in part due to improved management strategies for heart failure thereby decreasing incidence of CSA and unmasking a more prevalant OSA. Larger studies to further look into this will need to be conducted.
One of the factors that could contribute to the progressively declining course of heart failure may be sleep apnea. CPAP usage may improve cardiovascular function and therby delay heart transplant, decrease days and number of hospitalizations and improve quality of life. Therefore, we believe that OSA may be under diagnosed in severe heart failure.
Pooja Raju, No Financial Disclosure Information; No Product/Research Disclosure Information