Does the use of echocardiography LVEF as a gatekeeper improve the selective use of cardiac magnetic resonance for predicting MACE in patients discharged for STEMI?
Echocardiographic LVEF <50% effectively identifies STEMI patients who benefit most from CMR for long-term risk stratification, supporting a selective rather than indiscriminate use of CMR.
Abstract Background CMR permits robust risk stratification of discharged STEMI patients but an indiscriminate use in all cases is unfeasible. Purpose We evaluated the usefulness of left ventricular ejection fraction (LVEF) by echocardiography (Echo) as the gatekeeper for identifying those patients discharged for ST-segment elevation myocardial infarction (STEMI) who benefit most from cardiac magnetic resonance (CMR) for prognostic purposes. Methods Echo and CMR were performed in 1119 patients discharged for STEMI included in a multicenter registry. The prognostic power of CMR beyond Echo-LVEF was assessed using C-statistic, net reclassification index (NRI) and integrated discrimination improvement index (IDI). Results During a 4.8-year median follow-up, 136 (12%) first major adverse cardiac events (MACE) occurred (47 cardiovascular deaths and 89 re-admissions for acute heart failure). Lesser Echo-LVEF and CMR-LVEF associated with the occurrence of MACE but only CMR-LVEF and microvascular obstruction were independent predictors. The MACE rate significantly increased only in patients with CMR-LVEF 40% (≥50%: 7%, 40–49%: 9%, 40%: 27%, p0.001). The majority of patients (629, 56%) displayed Echo-LVEF ≥50% and most of them (94%) were at the “safe zone” (CMR-LVEF 40%). On the other hand, 490 patients (44%) exhibited Echo-LVEF 50% and 33% of them were incorrectly classified either in the “safe zone” (CMR-LVEF ≥40%) or in the “risk zone” (CMR-LVEF 40%). C-statistic, NRI and IDI demonstrated potent reclassification for MACE prediction by CMR in patients with Echo-LVEF 50% but not in those with Echo-LVEF ≥50%. Conclusions Echo-LVEF 50% identifies the subset of discharged STEMI patients who may benefit most from CMR in terms of long-term risk prediction. Figure 1. LVEF reclassification Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): This study was funded by “Instituto de Salud Carlos III” and “Fondos Europeos de Desarrollo Regional FEDER” (PIE15/00013, PI17/01836, and CIBERCV16/11/00486 grants).
Garces et al. (Sun,) studied this question.