Prediction of Mortality After Primary Percutaneous Coronary Intervention for Acute Myocardial Infarction

Objectives

We sought to develop a simple risk score for predicting mortality after primary percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI).

Background

Accurate risk stratification after primary PCI is important. Previous risk scores after reperfusion therapy have incorporated clinical ± angiographic variables but have not considered baseline left ventricular function. Moreover, prior studies have not been validated against independent databases or studies.

Methods

The databases from the two largest multicenter, randomized AMI trials of primary PCI were utilized for score derivation (the Controlled Abciximab and Device Investigation to Lower Late Angioplasty Complications [CADILLAC] trial, n = 2,082) and subsequent validation (the Stent-Primary Angioplasty in Myocardial Infarction [Stent-PAMI] trial, n = 900). Logistic regression and the jackknife procedure were used to select correlates of one-year mortality that were subsequently weighted and integrated into an integer scoring system.

Results

Seven variables selected from the initial multivariate model were weighted proportionally to their respective odds ratio for one-year mortality (age >65 years [2 points], Killip class 2/3 [3 points], baseline left ventricular ejection fraction <40% [4 points], anemia [2 points], renal insufficiency [3 points], triple-vessel disease [2 points], and post-procedural Thrombolysis In Myocardial Infarction flow grade [2 points]). Three strata of risk were defined (low risk, score 0 to 2; intermediate risk, score 3 to 5; and high risk, score ≥6) with excellent prognostic accuracy for survival in the derivation and validation sets (cstatistics = 0.83 and 0.81 for 30-day mortality and 0.79 and 0.78 for 1-year mortality, respectively).

Conclusions

In AMI patients treated with primary PCI, seven risk factors readily available at the time of intervention accurately predict short- and long-term mortality. Of note, measurement of baseline left ventricular function is the single most powerful predictor of survival and should be incorporated into risk score models.