Evolution of the coronary care unit: Clinical characteristics and temporal trends in healthcare delivery and outcomes*

Objective: To describe long-term temporal trends in patient characteristics, processes of care, and in-hospital outcomes among unselected admissions within the contemporary coronary care unit. Design: Hospital administrative database that records both payment and operation data. Setting: Coronary care unit of a large, academic, tertiary-care medical institution. Patients: A total of 29,275 patients admitted from January 1, 1989 through December 31, 2006. Interventions: Unadjusted time-trend plots were created for all variables of interest, and multivariable modeling of coronary care unit death was performed. Measurements and Main Results: Temporal trends in Coronary Care Unit and in-hospital mortality, length-of-stay, demographic characteristics, discharge diagnoses, Coronary Care Unit procedures, and Charlson comorbidity scores were evaluated. Admission severity increased significantly over time (p < .001), but hospital length-of-stay decreased (p < .001). The proportion of coronary care unit admissions with non-ST-segment elevation myocardial infarction increased (p < .001), whereas ST-segment elevation myocardial infarction decreased (p < .001). The prevalence of non-cardiovascular diagnoses increased, with the rate greatest for comorbid critical illnesses, including sepsis, acute kidney injury, and respiratory failure (all p < .001). The use of non-cardiac procedures, such as mechanical ventilation and central venous catheterization, also increased over time (p < .001). Unadjusted coronary care unit and in-hospital mortality did not change during the study period, although death did decrease in the adjusted setting. Conclusions: Substantial changes have occurred over time in patient characteristics, diagnoses, and procedures within the coronary care unit of a large, academic medical center. In particular, there have been significant increases in noncardiovascular critical illness, the results of which may be influencing patient outcomes. These findings underscore an existing need to clarify the role of the coronary care unit in contemporary cardiovascular care and to develop strategies for optimal training, staffing, and clinical investigation.

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