Patients with central sleep apnea (CSA) and chronic heart failure (CHF) have a higher risk of being hospitalized and higher mortality rates than people with both obstructive sleep apnea (OSA) and CSA. This is true whether or not they get adaptive servo-ventilation (ASV) therapy. These results were determined in a French prospective observational study from the FACE Multicentre National Cohort Study and were presented at the 2016 ATS International Conference.
Lead author of the study, Renaud Tamisier, MD, PhD, who is from Grenoble Alpes University in France states that these results show what happens in real life with these individuals. It focuses on how heart failure patients can have different traits in terms of cardiovascular and pulmonary diseases. These results will be necessary in figuring out who will benefit from central sleep apnea treatments.
CSA touches the lives of about 10-20% of the sleep apnea population, but it is much less common than OSA, which some patients with CSA may have as well. About 30% of CHF patients suffer from CSA, which results in their having breathing instability during sleep and going between hyperventilation and hypoventilation. Hyperventilation is caused by an over sensitivity to carbon dioxide, while hypoventilation leads to apnea (stops in breathing). This is very different from OSA, where the cause is due to throat and airway blockage.
ASV is a therapy that is like advanced positive airway pressure, and this technology has shown far more effective in the treatment of CSA than CPAP, especially in those with CHF because it improves heart function. Since CHF is a condition where the heart does not pump blood properly, this has shown to be a beneficial treatment.
There are 301 stable CHF patients who are part of the FACE study, each with a preserved and low ejection fraction. Of these patients, 80% have functional class II to III heart failure per the New York Heart Association – a system of classification with CHF severity categories rated on a scale of one to four. This part of the study requires researchers to look at mortality and morbidity, sleep and respiratory data, as well as changes in cardiac function. They also looked at whether there was preserved or reduced LVEF (left ventricular ejection fraction), co-existing CSA-OSA or predominant CSA, and whether or not they were compliant with ASV therapy.
Co-existing CSA-OSA and predominant CSA made up 30% and 70% of participants, respectively. Of those, 75% had severe sleep apnea. Only 74% of patients consented to receive ASV therapy.
Even though CSA-OSA and predominant CSA participants had comparable severity in their heart disease, those with predominant CSA and more severe NYHA classification were at higher risk of mortality and had more unplanned hospitalizations. This was true whether or not ASV therapy was used.
Dr. Tamisier and colleagues already knew that patients with CHF and CSA had a poor prognosis; however, the significance of the relationship is still a question. It is uncertain whether it is related to their CHF status or if CSA has a pathogenesis that worsens CHF. Researchers are hopeful that the answers to these questions lie in further evaluation of the data.
Additionally, Dr. Tamisier noted that patients with CHF who have the most severe NYHA classification did not have a different prognosis whether or not they used ASV therapy. Another study, the SERVE-HF trial, noted different findings, where patients that had the most severe case of CHF did not benefit from ASV treatment. There remains the question of whether alternative treatments are of value.
The FACE study has given data on patients with CHF that are eligible to receive ASV. These patients will be followed for two years. There are a total of 22 research centers participating in this study, with the completion of data collection expected to be toward the end of 2019.
The trial noted above (SERVE-HF) was a randomized trial that took data on the effectiveness of ASV treatment in those with low ejection fraction heart failure along with Cheyne-Stokes or predominant CSA. Cheyne-Stokes is very often associated with CSA.
Reference: http://www.eurekalert.org/pub_releases/2016-05/ats-hfp050916.php
Author: Rachael Herman is a professional writer with an extensive background in medical writing, research, and language development. Her hobbies include hiking in the Rockies, cooking, and reading.
