Predictive Power of Ejection Fraction and Renal Failure
Background: Ejection fraction (EF) and renal failure (RF) are powerful predictors of mortality in patients with myocardial infarction (MI). There are limited data assessing the predictive value of EF and RF compared with clinical variables in patients without ST elevation using troponin as the diagnostic MI criteria.
Methods: Consecutive patients admitted from the emergency department underwent serial assessment of cardiac markers, including troponin I. Abnormal EF was defined as <50%; RF, as creatinine clearance (CrCl) <60 mL/min. Multivariate analysis was used to compare clinical variables, CrCl, and EF for predicting short- and long-term outcomes.
Results: A total of 3074 patients had EF assessed. Mild to moderately reduced EF and CrCl were present in 639 (21%) and 582 (19%) patients, with 403 (13%) and 233 (7.6%) having severe systolic dysfunction and severe RF, respectively. Abnormal EF and RF were both present in 13% of patients (1-year mortality 26%), whereas 52% had both normal EF and CrCl (1-year mortality 3.2%). The presence of either systolic dysfunction or RF increased mortality 3- to 4-fold compared with patients without either. The most important multivariate predictors of 1-year mortality were EF (OR 2.6 [95% CI 1.7-3.8, P < .0001]) and CrCl (OR 2.8 [95% CI 1.8-4.2, P < .0001]).
Conclusions: Both RF and EF are strong predictors of cardiac mortality in patients admitted for exclusion of MI. Prediction models that do not include these 2 variables will underestimate risk.

Ejection fraction (EF) has been consistently shown to be a powerful predictor of outcomes in patients after myocardial infarction (MI). The relationship is not linear because there is a sharp increase in mortality once EF decreases below 40%. Because most predictive data for EF were derived from clinical trials that were primarily limited to patients with ST-elevation MI, there is little information assessing its prognostic value in the broader spectrum of non-ST elevation acute coronary syndromes (ACS).

Renal failure (RF) is being increasingly recognized as a strong predictor of adverse outcomes in a variety of ACS patient groups. Because RF has been an exclusion criterion for most clinical trials, minimal outcomes data for patients with more severe RF are available.

Based on its high sensitivity and specificity for detecting myocardial necrosis, current guidelines recommend that cardiac troponin be the standard for diagnosing MI. It is unknown whether EF has the same predictive ability in patients who have smaller degrees of necrosis now identified by troponin elevations. In addition, there is little information comparing the relationship between EF, troponin I (TnI), renal function, and outcomes in a broad group of patients admitted for possible MI. Therefore, we assessed the effect of these variables on 30-day and 1-year outcomes in a large consecutive group of patients admitted from the emergency department (ED) for exclusion of myocardial ischemia.