Objective: To evaluate the relation of central sleep apnoea (CSA) to the severity and short-term prognosis of patients who experience acute coronary syndrome (ACS).
Methods: Observational study with cross-sectional and longitudinal analyses. Patients acutely admitted to participating hospitals because of ACS underwent respiratory polygraphy during the first 24 to 72 h. CSA was defined as an apnoea-hypopnoea index (AHI) >15 events•h-1 (>50% of central apnoeas). ACS severity (Killip class, ejection fraction, number of diseased vessels and peak plasma troponin) was evaluated at baseline, and short-term prognosis (length of hospitalization, complications and mortality) was evaluated at discharge.
Results: A total of 68 CSA patients (AHI 31±18 events•h-1, 64±12 years, 87% males) and 92 controls (AHI 7±5 events•h-1, 62±12 years, 84% males) were included in the analyses. After adjusting for age, body mass index, hypertension and smoking status, patients diagnosed with CSA spent more days in the coronary unit compared with controls (3.7±2.9 vs. 1.5±1.7; p<0.001) and had a worse Killip class (Killip I: 16% vs. 96%; p<0.001). No differences were observed in ejection fraction estimates.
Conclusions: CSA patients exhibited increased ACS severity as indicated by their Killip classification. These patients had a worse prognosis, with longer lengths of stay in the coronary care units. Our results highlight the relevance of CSA in patients suffering ACS episodes and suggest that diagnosing CSA may be a useful strategy to improve the management of certain ACS patients.