Validation of the Killip-Kimball classification and late mortality after acute myocardial infarction

Area of Science:

• Cardiology
• Clinical Risk Stratification
• Acute Myocardial Infarction

Background:

• The Killip and Kimball classification was developed in the 1960s to assess in-hospital mortality risk in acute myocardial infarction (AMI) patients.
• It guided care management in Coronary Care Units (CCUs).

Purpose of the Study:

• To validate the Killip classification's prognostic value for long-term mortality.
• To compare its predictive power in non-ST-segment elevation MI (NSTEMI) versus ST-segment elevation MI (STEMI) patients.
• To assess its relevance in the current era of reperfusion and advanced antithrombotic therapies.

Main Methods:

• Evaluation of 1906 patients with documented AMI admitted to CCU between 1995 and 2011.
• A mean follow-up of 5 years was used to assess total mortality.
• Kaplan-Meier curves and Cox proportional regression models were employed for survival analysis and independent predictor assessment, stratified by AMI type.

Main Results:

• Significant differences in mortality proportions and survival distributions were observed across Killip classes greater than 1 (p <0.001).
• The Killip classification demonstrated a similar prognostic pattern in both NSTEMI and STEMI patient groups.
• Cox models confirmed Killip classification as a significant, consistent, and independent predictor of mortality in both NSTEMI and STEMI.

Conclusions:

• The Killip and Kimball classification retains significant prognostic value for long-term mortality up to 5 years post-AMI.
• Its predictive performance is consistent across both NSTEMI and STEMI patient populations.
• The classification remains a relevant tool for risk stratification in contemporary cardiovascular care.