ACEF score adapted to ST-elevation myocardial infarction patients: The ACEF-STEMI score

Highlights

• Original ACEF and ACEF-MDRD score only weakly predicted adverse outcome after STEMI.

• The novel ACEF-STEMI score showed strong value for prediction of post-STEMI MACE.

• Prognostic validity of ACEF-STEMI was incremental to original ACEF or ACEF-MDRD.

Abstract

Background

The age, creatinine and ejection fraction (ACEF) score has originally been developed for risk stratification of patients undergoing elective cardiac surgery. In patients with stable coronary artery disease treated by percutaneous coronary intervention (PCI), the prognostic accuracy of ACEF could be further improved by modifying the original scoring system (called “modified ACEF” or “ACEF-MDRD”). We aimed to specifically adapt the ACEF score for risk assessment of ST-elevation myocardial infarction (STEMI) patients.

Methods

In this observational study, 390 STEMI patients undergoing primary PCI were included. Clinical endpoint was the occurrence of major adverse cardiovascular events (MACE) comprising all-cause mortality, non-fatal re-infarction, stroke and new congestive heart failure.

Results

Original ACEF (area under the curve (AUC):0.63 [95%CI:0.53–0.73]; p = 0.01) and ACEF-MDRD score (AUC:0.62 [95%CI:0.53–0.72]; p = 0.01) significantly but weakly predicted MACE (n = 41, 11%). The addition of creatinine > 2 mg/dl (as suggested in original ACEF, p = 0.32) or eGFR steps as proposed in ACEF-MDRD (p = 0.17) to age/EF ratio were not associated with net reclassification improvements (NRI), but ΔeGRF (>10 ml/min/1.73 m² decrease within three days after PCI) led to an NRI of 0.29 (95%CI:0.14–0.45; p < 0.001). Replacement of cross-sectional renal assessment by ΔeGRF and addition of 3 clinical parameters (diabetes, anterior infarct location and C-reactive protein), forming the new ACEF-STEMI score, led to a significant improvement in MACE prediction (AUC:0.75 [95%CI:0.66–0.84]) as compared to original ACEF or ACEF-MDRD (both p = 0.03).

Conclusions

In STEMI patients undergoing primary PCI, the novel ACEF-STEMI score provided strong prognostic value and superior discriminative ability as compared to the previously described original ACEF or ACEF-MDRD scores.

Introduction

Despite crucial advances in the management of patients suffering from acute ST-elevation myocardial infarction (STEMI) over the last years, the risk of further cardiovascular complications following STEMI has remained substantial [[1], [2], [3]]. Therefore, accurate risk assessment and stratification, preferably at a very early stage after STEMI, is of key relevance in daily clinical practice [1,4].

The current literature provides several models and scores of different complexity allowing the identification of high-risk STEMI patients [[5], [6], [7]]. One simple cardiovascular risk score is the age, creatinine and ejection fraction (ACEF) score [[8], [9], [10]]. The ACEF score has originally been developed to predict mortality in patients undergoing elective coronary artery bypass graft surgery, demonstrating similar or even superior predictive value as compared to more complex scoring systems [8]. Subsequent investigations could also demonstrate prognostic validity of ACEF score in “all comer” patients undergoing primary percutaneous coronary intervention (PPCI) [11]. For the subgroup of patients with stable coronary artery disease, Capodanno et al. proposed that the incorporation of estimated glomerular filtration rate (eGFR) as semi-continuous parameter (ACEF-MDRD) instead of serum creatinine concentrations would improve risk prediction [12]. However, such attempts of ACEF score modifications in order to improve risk stratification have never been performed in the STEMI population so far.

Besides prediction of mortality, ACEF score was also shown to be associated with peri-interventional complications and insufficient interventional revascularization, reflected by the no-reflow phenomenon, in patients undergoing PPCI for STEMI [13]. No-reflow is an angiographic indicator of myocardial microvascular injury (MVI) [14], which can most accurately be assessed in vivo by cardiac magnetic resonance (CMR) imaging [14]. Presence of MVI is of crucial clinical importance in the setting of acute STEMI and represents one of the strongest predictor of post-infarction major adverse cardiovascular events (MACE) [14,15]. Indeed, over the last years several studies could highlight the prognostic validity of MVI for patients surviving acute STEMI [15,16]. Due to the lack of CMR studies, it is, however, unclear whether ACEF score could predict MVI following STEMI.

Primary objective of the present study was to (a) determine the value of the ACEF score (original ACEF and ACEF-MDRD) for the prediction of MACE following revascularized STEMI and to (b) improve the prognostic accuracy of the ACEF score model by either adjusting existing variables or including new clinical parameters significantly associated with MACE to establish a novel ACEF score specifically modified for STEMI survivors (ACEF-STEMI score). Secondary objective was to (c) investigate the relation of ACEF scores with the presence of MVI as determined by comprehensive CMR imaging.