Diagnostic studies have found that up to 70% of patients hospitalized for congestive heart failure (CHF) have sleep-disordered breathing (SDB)—often central or mixed sleep apnea. And because CHF patients are rarely screened, SDB is rarely diagnosed or treated. Presenters in Sleep-Disordered Breathing and Congestive Heart Failure: An Update! addressed this on Monday, October 19. The session is available for viewing on the virtual CHEST 2020 meeting platform through January 18, 2021, for registered attendees.
“The prevalence of SDB is very high and is largely undiagnosed in patients with heart failure,” said Ritwick Agrawal, MD, FCCP, assistant professor of medicine at Baylor College of Medicine and the Sleep Disorders Clinical & Research Center at the Michael E. DeBakey Veterans Affairs Medical Center in Houston. “Heart failure patients have atypical symptoms with less subjective daytime sleepiness, so they are less likely to be referred. We have a phenotype of patients who are sleeping less and less well and are not being diagnosed.”
For patients hospitalized with CHF, SDB is associated with roughly a doubling in the risk of death in heart failure. Diagnosing and treating SDB in CHF patients can address the increased risk, but there are significant barriers to screening hospitalized patients.
Because CHF patients do not complain of daytime sleepiness, clinicians seldom think of screening. If they do consider screening, the familiar Epworth Sleepiness Scale and STOP-BANG instruments are not well validated for in-patient populations.
Because sleep medicine is traditionally an outpatient service, it may not be readily available on the inpatient side. And COVID-19 adds another layer of complexity.
None of those barriers are insurmountable. A combination of inpatient clinical evaluation and STOP-BANG can identify SDB nearly as well as conventional outpatient tools. Unattended sleep studies show a strong correlation with attended studies in this population.
High-resolution pulse oximetry is another useful tool that is readily available for most inpatients. Results track conventional sleep study results.
“We don’t have long-term data on treatment,” Dr. Agrawal said. “But there are positive suggestions in 6-month reports.”
What’s the best approach to SDB in patients with CHF? It depends.
“We need to be thinking about patient phenotypes,” said Shahrokh Javaheri, MD, FCCP, professor emeritus of medicine at the University of Cincinnati and adjunct professor of cardiology at Ohio State Medical School.
“There is not one single therapy that completely eliminates SDB in all patients. There are clearly individuals who will not respond to oxygen, just like there are those who will not respond to CPAP, theophylline, and other interventions.”
Many patients with HFrEF and SDB improve with positive airway pressure treatment. But a subset of patients with oxygen desaturation may do worse with CPAP, BiPAP, or ASV, which can increase intrathoracic pressure. These patients may do better with oxygen therapy.
Phrenic nerve stimulation (PNS) is a more recent alternative for patients with CSA. It helps reduce end tidal CO2 pressure and hyperventilation.
A stimulator is implanted in the right pectoral area with a pacing lead in the Azygous vein and a pacing lead in the left pericardio-phrenic vein, which runs near the phrenic nerve. A pivotal 12-month trial published in 2016 and a pooled cohort analysis from 2019 showed sustained improvements in multiple outcomes.
“We can improve breathing, quality of life, and quality of sleep with PNS for patients with CSA, especially those with heart failure,” said Chitra Lal, MD, FCCP, ATSF, associate professor of medicine at Medical University of South Carolina. “PNS may also improve LVEF and CHF hospitalization rates.”