Usefulness of endothelin-1 assessment in acute myocardial infarction

Abstract

Introduction and objectives: High endothelin-1 (ET-1) levels have been linked to poor clinical outcomes after ST-segment elevation myocardial infarction (STEMI). Vasoconstriction of the coronary microcirculation seems to be the underlying mechanism. The aim of the study was to assess the effect of ET-1 on microvascular integrity, infarct size, left ventricular ejection fraction (LVEF) and myocardial salvage in evolving myocardial infarction (MI).

Methods: We measured ET-1 levels acutely (6-24h) in 127 patients presenting with their first STEMI. Contrast-enhanced cardiac magnetic resonance (ce-CMR) was performed in 94 patients within 1 week to assess microvascular obstruction (MO), infarct size and LVEF. A myocardial salvage index (MSI) was defined as the percentage of at-risk angiographic area without necrosis on the ce-CMR.

Results: Mean age was 60.9 ± 11.8 years and 98 (77%) were males. Median ET-1 level within the first 24h was 6.8 pg/mL (25(th) -75(th) percentile range: 5.4-8.5 pg/mL). Patients with ET-1 concentrations over the median presented higher percentage of MO (77.7% for ET-1>6.8 pg/mL vs. 16.6% for ET-1 ≤ 6.8 pg/mL, P<.001) and lower MSI values (13.8 ± 26% for ET-1>6.8 pg/mL vs. 37.4 (26%) for ET-1 ≤ 6.8 pg/mL, P=.02). ET-1 levels did not show a significant association with infarct size (P=.11) and LVEF (P=.16). Multivariate analysis found ET-1 to be a significant predictor of MO (OR=2.78; CI 95% 1.16-6.66; P=.021) and MSI ≤ Percentile 25 (OR=1.69, CI 95% 1.01-2.81; P=.04).

Conclusions: High ET-1 levels after myocardial infarction are associated with the presence of microvascular obstruction and lower myocardial salvage index.