Clinical Predictors and Prognostic Role of High Killip Class in Patients with a First Episode of Anterior ST-segment Elevation Acute Myocardial Infarction

Aims: Killip classification is a simple and fast clinical tool for risk stratification of patients presenting with acute coronary syndrome (ACS). However, the clinical features and predictors of high Killip class at admission, and its prognostic impact in patients presenting with anterior ST elevation MI (STEMI) as first clinical cardiovascular event are still poorly known. The aim of this study was to identify the predictors of high Killip class and its impact on in-hospital and follow-up outcomes.

Methods: We prospectively enrolled patients with unheralded anterior STEMI because of proximal or mid left anterior descending (LAD) artery categorized according to Killip classification. Patients' characteristics, in-hospital complications and major adverse cardiovascular events (MACEs; composite of all-cause death, heart failure hospitalization and new-onset ACS) at follow-up were collected.

Results: We enrolled 147 patients [age 66.16±13.33, 113 male patients (76.9%)]. Killip class III--IV occurred in 22 (15%) patients. The median duration of follow-up was 12 [6--15.1] months. At multivariate analysis age [hazard ratio 1.137, 95% CI (1.068--1.209), P < 0.001], prehospital cardiac arrest [hazard ratio 12.145, 95% CI (1.710--86.254), P = 0.013] and proximal LAD lesion [hazard ratio 5.066, 95% CI (1.400--18.334), P = 0.013] were predictive of Killip class III--IV at admission. At multivariate analysis, Killip class III--IV was an independent predictor of in-hospital mortality [hazard ratio 7.790, 95% CI (1.024--59.276], P = 0.047 and of MACEs [hazard ratio 4.155 (1.558--11.082), P = 0.004) at follow-up.

Conclusion: Killip classification performed at the time of admission is a simple and useful clinical marker of a high risk of early and late adverse cardiovascular events.