Combined use of trimethylamine N-oxide with BNP for risk stratification in heart failure with preserved ejection fraction: findings from the DIAMONDHFpEF study
Circulating levels of trimethylamine N-oxide (TMAO), a gut microbiome-mediated metabolite related to the western diet,1,2 have been shown to be associated with risk stratification and outcome in patients with heart failure (HF) with reduced ejection fraction (HFrEF).3,,–6 The aim of the present study was to assess the associations between TMAO with outcomes in patients with HF with preserved ejection fraction (HFpEF). To investigate the recently identified link between the gut and HF (namely the ‘gut hypothesis’), TMAO levels were measured in 118 patients with HFpEF, 38 patients with HFrEF and 40 healthy volunteer participants (sex/age matched) with available baseline plasma samples from the Developing Imaging And plasMa biOmarkers iN Describing Heart Failure With Preserved Ejection Fraction (DIAMONDHFpEF) cohort, a prospective, observational, single-centre study aimed at developing imaging and plasma biomarkers of novel pathophysiological patterns in HFpEF (NCT03050593).7 Plasma levels of TMAO were measured using liquid chromatography tandem mass spectrometry, a high throughput, reproducible and accurate method.3,5,8 B-type natriuretic peptide (BNP) was measured using a commercial immunoassay (Siemens, Erlangen, Germany). All patients had blood tests, transthoracic echocardiography (TTE; Philips iE33, Amsterdam, The Netherlands) and cardiac magnetic resonance (CMR) imaging (Siemens Skyra, Erlangen, Germany) during the same visit. Primary outcomes were defined as the composite endpoint of all-cause mortality or hospitalisation for HF at 18 months (short-term) and at 60 months (long-term).