Acyl ghrelin increases cardiac output while preserving right ventricular-pulmonary arterial coupling in heart failure.

AIM: Acyl ghrelin increases cardiac output (CO) in heart failure with reduced ejection fraction (HFrEF). This could impair the right ventricular-pulmonary arterial coupling (RVPAC), both through an increased venous return and right ventricular afterload. We aim to investigate if acyl ghrelin increases CO with or without worsening the right-sided haemodynamics in HFrEF assessed by RVPAC. METHODS AND RESULTS: The Karolinska Acyl ghrelin Trial was a randomized double-blind placebo-controlled trial of acyl ghrelin versus placebo (120-min intravenous infusion) in HFrEF. RVPAC was assessed echocardiographically at baseline and 120 min. ANOVA was used for difference in change between acyl ghrelin versus placebo, adjusted for baseline values. Of the 30 randomized patients, 22 had available RVPAC (acyl ghrelin n = 12, placebo n = 10). Despite a 15% increase in CO in the acyl ghrelin group (from 4.0 (3.5-4.6) to 4.6 (3.9-6.1) L/min, P = 0.003), RVPAC remained unchanged; 5.9 (5.3-7.6) to 6.3 (4.8-7.5) mm·(m/s)-1 , P = 0.372, while RVPAC was reduced in the placebo group, 5.2 (4.3-6.4) to 4.8 (4.2-5.8) mm·(m/s)-1 , P = 0.035. Comparing change between groups, CO increased in the acyl ghrelin group versus placebo (P = 0.036) while RVPAC and the right ventricular pressure gradient remained unchanged. CONCLUSION: Treatment with acyl ghrelin increases CO while preserving or even improving RVPAC in HFrEF, possibly due to increased contractility, reduced PVR and/or reduced left sided filling pressures. These potential effects strengthen the role of acyl ghrelin therapy in HFrEF with right ventricular failure.

Regional differences and coronary microvascular dysfunction in heart failure with preserved ejection fraction.

AIMS: In heart failure with preserved ejection fraction (HFpEF), regional heterogeneity of clinical phenotypes is increasingly recognized, with coronary microvascular dysfunction (CMD) potentially being a common shared feature. We sought to determine the regional differences in clinical characteristics and prevalence of CMD in HFpEF. METHODS AND RESULTS: We analysed clinical characteristics and CMD in 202 patients with stable HFpEF (left ventricular ejection fraction ≥40%) in Finland, Singapore, Sweden, and United States in the multicentre PROMIS-HFpEF study. Patients with unrevascularized macrovascular coronary artery disease were excluded. CMD was assessed using Doppler echocardiography and defined as coronary flow reserve (adenosine-induced vs. resting flow) < 2.5. Patients from Singapore had the lowest body mass index yet highest prevalence of hypertension, dyslipidaemia, and diabetes; patients from Finland and Sweden were oldest, with the most atrial fibrillation, chronic kidney disease, and high smoking rates; and those from United States were youngest and most obese. The prevalence of CMD was 88% in Finland, 80% in Singapore, 77% in Sweden, and 59% in the United States; however, non-significant after adjustment for age, sex, N-terminal pro-brain natriuretic peptide, smoking, left atrial reservoir strain, and atrial fibrillation. Associations between CMD and clinical characteristics did not differ based on region (interaction analysis). CONCLUSIONS: Despite regional differences in clinical characteristics, CMD was present in the majority of patients with HFpEF across different regions of the world with the lowest prevalence in the United States. This difference was explained by differences in patient characteristics. CMD could be a common therapeutic target across regions.