Collagen biomarker bioprofiles predicting the antifibrotic response to eplerenone in myocardial infarction: findings from the REMINDER trial

Mineralocorticoid receptor in cardiovascular diseases-Clinical trials and mechanistic insights

Aldosterone binds to the mineralocorticoid receptor (NR3C2), a transcription factor of the nuclear receptor family, present in the kidney and in various other non-epithelial cells including the heart and the vasculature. Indeed, extra-renal pathophysiological effects of this hormone have been characterized, extending its actions to the cardiovascular system. A growing body of clinical and pre-clinical evidence suggests that mineralocorticoid receptor overactivation plays an important pathophysiological role in cardiovascular remodelling by promoting cardiac hypertrophy, fibrosis, arterial stiffness and in inflammation and oxidative stress. The following review article outlines the role of mineralocorticoid receptor in cardiovascular disease with a focus on myocardial remodelling and heart failure (HF) including clinical trials as well as cellular and animal studies.

MRAs in Elderly HF Patients: Individual Patient-Data Meta-Analysis of RALES, EMPHASIS-HF, and TOPCAT

OBJECTIVES

This study sought to assess the effect of MRA treatment (vs. placebo) in older patients (≥75 years of age) compared with younger patients (<75 years of age) with heart failure (HF).

BACKGROUND

Mineralocorticoid receptor antagonists (MRAs) have been shown to reduce morbidity and mortality in patients with HF with reduced ejection fraction (HFrEF) and in a subset of patients with HF with preserved EF (HFpEF). Notwithstanding, MRAs are underused, especially in the elderly. Pooling the individual patient data (IPD) provided more statistical power with which to assess the efficacy and safety of MRA treatment in this subpopulation.

METHODS

An IPD meta-analysis was performed using Cox proportional hazards models stratified by trial. A total of 1,756 patients (853 randomized to placebo and 903 to MRA) ≥75 years of age, along with 4,411 patients (2,242 randomized to placebo and 2,169 to MRA) <75 years of age were included. The primary outcome was a composite of death from cardiovascular causes or hospitalization for HF.

RESULTS

The treatment groups were well balanced. Patients ≥75 years of age or older and those 80 years of age, 61% were male, 30% had diabetes, and the mean estimated glomerular filtration rate 59 ml/min. The primary outcome occurred in 331 patients (38.8%) in the placebo group versus 281 (31.1%) in the MRA group (hazard ratio: 0.74; 95% confidence interval: 0.63 to 0.86; p < 0.001; and the heterogeneity p value [heterogeneity p = Cochran's Q p value of treatment effect by study interaction] was 0.52). Cardiovascular death and all-cause death were also reduced by MRAs without significant between-trial or age (younger vs. older) heterogeneity. Worsening renal function and hyperkalemia occurred more frequently in patients taking MRAs (vs. placebo). Compared to younger patients, worsening renal function (but not hyperkalemia) was found more frequently in the elderly.

CONCLUSIONS

MRAs reduced morbidity and mortality in elderly patients with HF, a beneficial effect that is more marked in patients with HFrEF but homogenous across HFrEF and HFpEF. Implementation of measures that increase MRA treatment in this population are warranted.

Polyhedral erythrocytes in intracoronary thrombus and their association with reperfusion in myocardial infarction

OBJECTIVE

The tightly packed arrays of polyhedral erythrocytes, polyhedrocytes, formed during thrombus contraction, have been detected in some intracoronary thrombi (ICT) obtained from patients with ST-segment elevation myocardial infarction (STEMI). We sought to investigate determinants of polyhedrocyte content in ICT and its association with reperfusion in STEMI.

METHODS

We assessed the composition of ICT obtained during thrombectomy within 12 h since the symptom onset in 110 STEMI patients, following 300 mg of aspirin (n = 110) and 600 mg of clopidogrel (n = 75). The predominance of fibrin, erythrocytes, polyhedrocytes or platelets was evaluated using scanning electron microscopy.

RESULTS

Polyhedrocytes were found in 34 (30.9%) ICT, in which they covered 20-50% (median 38.8%) fields of view. Patients with polyhedrocytes in ICT had lower median minimal reference infarct-related artery (IRA) diameter by 20% (p < 0.0001) and area by 31% (p < 0.0001) versus those without polyhedrocytes. Time of ischemia showed association with the polyhedrocyte content (r = 0.26, p = 0.007). By multivariate analysis, minimal IRA diameter (β = - 0.50, p < 0.0001) and ischemia time (β = 0.20, p = 0.035) independently affected polyhedrocyte content in ICT (R² = 0.45, p < 0.0001). Patients with ischemia time of > 3 h and polyhedrocytes present in ICT had more frequently TIMI-2/3 flow after thrombus aspiration (96% vs. 67%, p = 0.02) and final TIMI-2/3 myocardial perfusion grade (92% vs. 57%, p = 0.044) versus those without polyhedrocytes.

CONCLUSIONS

Our findings indicate that the presence of polyhedrocytes in ICT, observed in one-third of STEMI patients, is associated with smaller minimal IRA diameter, prolonged ischemia and their formation in late presenters is associated with more effective thrombus aspiration and better myocardial reperfusion.