Novel Echocardiographic Risk Model Found to Predict Outcomes After PCI for STEMI

A novel echocardiographic risk stratification model was found to accurately predict outcomes in patients who underwent primary percutaneous coronary intervention (PCI) for the treatment of an ST-segment elevation myocardial infarction (STEMI), according to study results published in The American Journal of Cardiology.

Although left ventricular ejection fraction (LVEF) remains the gold standard tool to evaluate the prognosis of patients with STEMI, other echocardiographic measures may offer additional useful information.

In this single-center prospective study, 373 patients who underwent PCI after experiencing STEMI (mean age, 62±11 years; 75.1% men) were enrolled (derivation cohort). Study participants were given echocardiograms a median of 2 days later. A validation cohort comprising 298 additional patients with STEMI patients who had PCI performed between January 2003 and November 2008 at the same center was derived from a clinical registry. The primary outcome was a composite of heart failure (HF) and cardiovascular (CV) mortality.

The derivation cohort had a mean LVEF of 46%, with 75% of patients exhibiting prevalent diastolic dysfunction. Over a mean follow-up period of 5.4 years, a total of 80 participants (21.4%) experienced the primary endpoint in the derivation cohort, with 70 cases of HF, 13 CV deaths, and 3 patients who had HF and subsequently died. In the validation cohort, a total of 127 patients (42.6%) experienced the primary outcome over a median 3.5 years of follow-up.

Four significant primary outcome predictors were identified in a stepwise backward Cox regression analysis: wall motion score index (WMSI), global longitudinal strain (GLS), E/e’ (estimating LV filling pressure), and E/global strain rate e (E/GLSRe). After multivariable adjustment, only WMSI was still found to independently predict the composite outcome (hazard ratio [HR], 3.23; 95% CI, 1.56-6.70; P =.002). Risk stratification was optimized using a classification and regression tree analysis, in which 3 key variables were identified as important components of the new model: WMSI, E/e’, and GLSRe.

Patients were divided into 3 groups based on risk level for HF and/or CV death: high risk (WMSI ≥2.22), intermediate risk (WMSI <2.22, E/e’ ≥7.6, and GLSRe <0.82s), and low risk (WMSI <2.22 and GLSRe ≥0.82s or E/e’ <7.6 and GLSRe <0.82s). There was an incremental risk detected when comparing patients in the low- vs intermediate-risk group (HR, 2.52; 95% CI, 1.24-5.11; P =.011) and vs the high-risk group (HR, 4.37; 95% CI, 1.40-13.66; P =.011). Validation was achieved in the second cohort, with a discrimination C-statistic of 0.71.

Study limitations include the exclusion of patients with atrial fibrillation and the use of different versions of the analytic software in the 2 cohorts.

“The model suggests that by only considering three measures (WMSI, GLSRe and E/e’) clinicians can risk-stratify patients in a simple and efficient manner without having to consider a large variety of other proposed predictors of outcome. This may ease and streamline the risk assessment in the clinic,” noted the authors.

Reference

Olsen FJ, Pedersen S, Skaarup KG, et al. A validated echocardiographic risk model for predicting outcome following ST-segment elevation myocardial infarction. Am J Cardiol. March 2020. doi:10.1016/j.amjcard.2020.02.024