Context: In acute myocardial infarction, the presence and severity of heart failure at the time of initial presentation have been formally categorized by the Killip classification. Although well studied in ST-elevation myocardial infarction, the prognostic importance of Killip classification in non-ST-elevation acute coronary syndromes is not well established.
Objectives: To determine the prognostic importance of physical examination for heart failure analyzed according to Killip classification in non-ST-elevation acute coronary syndromes and to understand its predictive value relative to other variables.
Design, setting, and patients: From April 2001 to September 2003, We analyzed information from 26 090 patients with non-ST-elevation acute coronary syndromes enrolled in the GUSTO IIb, PURSUIT, PARAGON A, and PARAGON B trials. Demographic information was categorized by Killip class. Killip classes III and IV were combined into 1 category. Multivariate Cox proportional hazard models were developed to determine the prognostic importance of Killip classification in comparison with other variables.
Main outcome measure: Association between Killip classification and all-cause mortality at 30 days and 6 months.
Results: Patients in Killip class II (n = 2513) and III/IV (n = 390) were older than those in Killip class I (n = 23 187), with higher rates of diabetes, prior myocardial infarction, ST depression, and elevated cardiac enzymes (all P<.001). Higher Killip class was associated with higher mortality at 30 days (2.8% in Killip class I vs 8.8% in class II vs 14.4% in class III/IV; P<.001) and 6 months (5.0% vs 14.7% vs 23.0%, respectively; P<.001). Patients with Killip class II, III, or IV constituted 11% of the overall population but accounted for approximately 30% of the deaths at both time points. In multivariate analysis, Killip class III/IV was the most powerful predictor of mortality at 30 days (hazard ratio [HR], 2.35; 95% confidence interval [CI], 1.69-3.26; P<.001) and 6 months (HR, 2.12; 95% CI, 1.63-2.75; P<.001). Killip class II was predictive of mortality at 30 days (HR, 1.73; 95% CI, 1.44-2.09; P<.001) and 6 months (HR, 1.52; 95% CI, 1.31-1.76; P<.001). Five factors-age, Killip classification, heart rate, systolic blood pressure, and ST depression-provided more than 70% of the prognostic information for 30-day and 6-month mortality.
Conclusions: Killip classification is a powerful independent predictor of all-cause mortality in patients with non-ST-elevation acute coronary syndromes. Age, Killip classification, heart rate, systolic blood pressure, and ST depression should receive particular attention in the initial assessment of these patients.