Acute renal failure in the cardiac care unit: Etiologies, outcomes, and prognostic factors

Background. Heart disease is a leading cause of hospitalizations, and its prevalence is expected to grow rapidly over the next few decades. The purpose of this study was to examine the incidence, etiologies, outcomes, and risk actors for mortality of acute renal failure (ARF) in cardiac care unit (CCU) patients. Methods. A retrospective, cohort study examining all patients who developed ARF while in the CCU at Barnes-Jewish Hospital over a 17-month time period was performed. Charts were reviewed to determine etiologies, hospital mortality rates, and risk factors for mortality. Results. Four percent of admissions to the CCU met criteria for ARF while in the unit. The etiologies of ARF were congestive heart failure (CHF: 35%), multifactorial (usually involving CHF: 26%), arrest/arrhythmia (13%), contrast (11%), volume depletion (6%), sepsis (6%) and obstruction (3%). The mortality rate was 50%. Oliguria, mechanical ventilation, and decreased cardiac function were statistically significant risk factors for mortality by univariate but not multivariate analysis. Thirty percent of patients with a cardiac index of less than 2.0 liter/min/m(2) survived to discharge. Conclusions. ARF occurs commonly in CCU patients and is associated with a high mortality rate. However, there are a significant number of survivors even among patients with severely depressed cardiac function.