Prognosis-based definition of left ventricular remodeling after ST-elevation myocardial infarction

Abstract

Objectives: Cardiac magnetic resonance (CMR) is the gold-standard modality for the assessment of left ventricular (LV) remodeling in ST-elevation myocardial infarction (STEMI) patients. However, the commonly used remodeling criteria have never been validated for hard clinical events. We therefore aimed to define clear CMR criteria of LV remodeling following STEMI with proven prognostic impact.

Methods: This observational study included 224 patients suffering from acute STEMI. CMR was performed within 1 week and 4 months after infarction to evaluate different remodeling criteria including relative changes in LV end-diastolic volume (%∆LVEDV), end-systolic volume (%∆LVESV), ejection fraction (%∆LVEF), and myocardial mass (%∆LVMM). Primary endpoint was the occurrence of major adverse cardiovascular events (MACE) including all-cause death, re-infarction, stroke, and new congestive heart failure 24 months following STEMI. Secondary endpoint was defined as composite of primary endpoint and cardiovascular hospitalization. The Mann-Whitney U test was applied to assess differences in LV remodeling measures between patients with and without MACE. Values for the prediction of primary and secondary endpoints were assessed by c-statistics and Cox regression analysis.

Results: The incidence of MACE (n = 13, 6%) was associated with higher %∆LVEDV (p = 0.002) and %∆LVMM (p = 0.02), whereas %∆LVESV and %∆LVEF were not significantly related to MACE (p > 0.05). The area under the curve (AUC) for the prediction of MACE was 0.76 (95% confidence interval [CI], 0.65-0.87) for %∆LVEDV (optimal cut-off 10%) and 0.69 (95%CI, 0.52-0.85) for %∆LVMM (optimal cut-off 5%). From all remodeling criteria, %∆LVEDV ≥ 10% showed highest hazard ratio (8.68 [95%CI, 2.39-31.56]; p = 0.001) for MACE. Regarding secondary endpoint (n = 35, 16%), also %∆LVEDV with an optimal threshold of 10% emerged as strongest prognosticator (AUC 0.66; 95%CI, 0.56-0.75; p = 0.004).

Conclusions: Following revascularized STEMI, %∆LVEDV ≥ 10% showed strongest association with clinical outcome, suggesting this criterion as preferred CMR-based definition of post-STEMI LV remodeling.

Key points: • CMR-determined %∆LVEDV and %∆LVMM were significantly associated with MACE following STEMI. • Neither %∆LVESV nor %∆LVEF showed a significant relation to MACE. • %∆LVEDV ≥ 10 was revealed as LV remodeling definition with highest prognostic validity.

Keywords: Magnetic resonance imaging; Prognosis; ST-elevation myocardial infarction.

Fig. 1

ROC curves of %∆LVEDV and %∆LVMM for the prediction of MACE. ROC, receiver operating characteristic; LVEDV, left ventricular end-diastolic volume; LVMM, left ventricular myocardial mass; MACE, major adverse cardiovascular events

Fig. 2

Kaplan–Meier curves displaying MACE-free survival according to the presence or absence of LV remodeling as defined by ∆LVEDV ≥ 10% (panel a) or ∆LVMM ≥ 5% (panel b). MACE, major adverse cardiovascular events; LVEDV, left ventricular end-diastolic volume; LVMM, left ventricular myocardial mass

Fig. 3

Relation of LV remodeling defined by ∆LVEDV ≥ 10% or/and ∆LVMM ≥ 5% with MACE. LVEDV, left ventricular end-diastolic volume; LVMM, left ventricular myocardial mass; MACE, major adverse cardiovascular events