National trends in coronary intensive care unit admissions, resource utilization, and outcomes

Emerging evidence suggests that coronary intensive care units are evolving into intensive care environments with an increasing burden of non-cardiovascular illness, but previous studies have been limited to older populations or single center experiences.

Canadian national health-care data was used to identify all patients ≥18 years admitted to dedicated coronary intensive care units (2005-2015) and admissions were categorized as primary cardiac or non-cardiac. The outcomes of interest included longitudinal trends in admission diagnoses, critical care therapies, and all-cause in-hospital mortality.

Among the 373,992 patients admitted to a coronary intensive care unit, minimal changes in the proportion of patients admitted with a primary cardiac (88.2% to 86.9%; p<0.001) and non-cardiac diagnoses (11.8% to 13.1%; p<0.001) were observed. Among cardiac admissions, a temporal increase in the proportion of ST-segment elevation myocardial infarction (19.4% to 24.1%, p<0.001), non-ST-segment elevation myocardial infarction (14.6% to 16.2%, p<0.001), heart failure (7.3% to 8.4%, p<0.001), shock (4.9% to 5.7%, p<0.001), and decline in unstable angina (4.9% to 4.0%, p<0.001) and stable coronary diseases (21.3% to 12.4%, p<0.001) was observed. The proportion of patients requiring critical care therapies (57.8% to 63.5%, p<0.001) including mechanical ventilation (9.6% to 13.1%, p<0.001) increased. In-hospital mortality rates for patients with primary cardiac (4.9% to 4.4%; adjusted odds ratio 0.71, 95% confidence interval 0.63-0.79) and non-cardiac (17.8% to 16.1%; adjusted odds ratio 0.84, 0.73-0.97) declined; results were consistent when stratified by academic vs community hospital, and by the presence of on-site percutaneous coronary intervention.

In a national dataset we observed a changing case-mix among patients admitted to a coronary intensive care unit, though the proportion of patients with a primary cardiac diagnosis remained stable. There was an increase in clinical acuity highlighted by critical care therapies, but in-hospital mortality rates for both primary cardiac and non-cardiac conditions declined across all hospitals. Our findings confirm the changing coronary intensive care unit case-mix and have implications for future coronary intensive care unit training and staffing.