Novel evidence for CPAP: patients with higher ∆HR benefit most

A re-analysis of the RICCADSA trial demonstrated that non-sleepy obstructive sleep apnoea patients with a higher respiratory event-related pulse rate response experienced a more the 50% risk reduction for a cardiovascular event when treated with CPAP.

According to 3 studies published previously, patients with coronary artery disease and non-sleepy obstructive sleep apnoea (OSA) have demonstrated no protective effect of continuous positive airway pressure (CPAP) on adverse cardiovascular outcomes. “Our previous study showed that those with non-sleepy OSA who demonstrated a greater respiratory event-related pulse rate response (ΔHR) are at an increased risk of cardiovascular (CV) morbidity and mortality,” Prof. Ali Azarbarzin (Harvard Medical School, Massachusetts, USA) explained. This was the rationale to test the hypothesis that patients with a higher pre-treatment ΔHR might benefit more from CPAP regarding CV outcomes. Therefore, Prof. Azarbarzin and his colleagues re-analysed data from the RICCADSA clinical trial (NCT00519597) of CV risk for non-sleepy OSA patients with heart disease.

During baseline polysomnography of the RICCADSA trial, ∆HR was measured from the oximetry pulse rate signals collected. The primary outcome of this trial was a composite of repeat revascularisation, myocardial infarction, stroke, and CV mortality. In the original study, the OSA effect on CV disease was similar across subgroups. The current analysis assessed whether the effect of the CPAP treatment on the primary outcome was influenced by ∆HR. “If this were true, then we would expect to see a preferential benefit from using CPAP on cardiac outcomes in those with the higher pulse rate response,” said Prof. Azarbarzin. “Indeed, this is what we found: the greater the pulse rate response, the greater the calculated treatment benefit of CPAP.”

∆HR measures were obtained in 92% of patients and 48 composite events over a 57-month median follow-up were recorded. A significant interaction between treatment and ∆HR was observed. CPAP provided protection from cardiac events in those non-sleepy OSA patients whose pulse rates rose significantly during sleep apnoea events. Patients with the highest ∆HR of 10 beats per minute experienced a more than 50% reduction of risk for a CV event when treated with CPAP.

“Our study provides novel evidence that a greater heart rate responsiveness to obstructive (airway) events is an identifiable, deleterious, and potentially reversible risk factor that could be used to select patients most likely to exhibit long-term CV benefit from CPAP therapy”, Prof. Azarbarzin concluded.

1. Azarbarzin A, et al. Cardiovascular benefit of CPAP is modified by the Sleep Apnea related pulse rate response in coronary artery disease patients with nonsleepy OSA: Findings from the RICCADSA randomized controlled trial. Session B14: Pathophysiology, cardiovascular disease, and COVID – what´s happening in sleep research right now. ATS 2021 International conference, 14-19 May 2021.

Posted on 20 May 20214 August 2021