Effect of Obstructive Sleep Apnoea and Its Treatment with Continuous Positive Airway Pressure on the Prevalence of Cardiovascular Events in Patients with Acute Coronary Syndrome (ISAACC Study): A Randomised Controlled Trial

Sánchez-de-la-Torre M, Sánchez-de-la-Torre A, Bertran S, et al; on behalf of the Spanish Sleep Network. [published online December 12, 2019]. Lancet Respir Med. [CrossRef] [PubMed]

The authors evaluated the effect of obstructive sleep apnoea (OSA) and its treatment with continuous positive airway pressure (CPAP) on the clinical evolution of patients with acute coronary syndrome (ACS). A multicentre, open-label, parallel-group, randomised controlled trial of patients with ACS at 15 hospitals was conducted in Spain. Eligible non-sleepy patients were men and women aged 18 years and older, admitted to hospital for documented symptoms of ACS. All patients underwent respiratory polygraphy during the first 24–72 h after admission. OSA patients were randomly assigned (1:1) to CPAP treatment plus usual care (CPAP group) or usual care alone (UC group). The primary endpoint was the prevalence of a composite of cardiovascular events (cardiovascular death or non-fatal events [acute myocardial infarction, non-fatal stroke, hospital admission for heart failure, and new hospitalisations for unstable angina or transient ischaemic attack]) in patients followed up for a minimum of 1 year. A total of 2834 patients with ACS had respiratory polygraphy, of whom 2551 (90·01%) were recruited. The prevalence of cardiovascular events was similar in the CPAP and UC groups (98 events [16%] vs 108 events [17%]; hazard ratio [HR] 0·89 [95% CI 0·68–1·17]; p=0·40) during follow-up. The prevalence of cardiovascular events seems not to be related to CPAP compliance or OSA severity. The authors conclude that among non-sleepy patients with ACS, the presence of OSA was not associated with an increased prevalence of cardiovascular events and treatment with CPAP did not significantly reduce this prevalence.