Prognostic importance of physical examination for heart failure in non-ST-elevation acute coronary syndromes - The enduring value of Killip classification

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 26090 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% Cl, 1.63-2.75; P<.001). Killip class 11 was predictive of mortality at 30 days (HR, 1.73; 95% Cl, 1.44-2.09; P<.001) and 6 months (HR, 1.52; 95% Cl, 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.