Left ventricular force with resting volumetric transthoracic echocardiography identifies different phenotypes in heart failure with preserved ejection fraction

Background

Heart failure and preserved ejection fraction (HFpEF) is a heterogeneous entity including patients with different phenotypes of reduced, normal, and supernormal left ventricular (LV) function.

Objectives

To assess the value of resting LV elastance with transthoracic echocardiography (TTE) to identify HFpEF phenotypes.

Methods

In a prospective, observational, multicenter study, 2380 HFpEF patients were recruited from July 2016 to May 2024 by 35 certified laboratories of 15 countries. HFpEF was diagnosed according to the European Society of Cardiology (ESC) guidelines. Systolic blood pressure (SBP) was measured. We assessed wall motion score index (WMSI), LV end-diastolic volume (EDV), end-systolic volume (ESV), EF, force (SBP/ESV), stroke volume (SV), arterial elastance (AE, SBP/SV), ventricular-arterial coupling (VAC, as SV/ESV), and left atrial volume index (LAVI). Global longitudinal strain (GLS) was available in 1164 (48.9%) patients. In 271 (11.4%) patients, N-terminal pro-brain natriuretic peptide (NT-proBNP) was assessed. Patients were divided into three groups based on rest force: low rest force group (< 25% percentile, Group 1), median rest force group (≥ 25% percentile & ≤ 75% percentile, Group 2), and high rest force group (> 75% percentile, Group 3).

Results

330 (13.9%) patients presented with ischemic RWMA. The 3 groups showed a gradient with descending values (Group 3>2>1) for SBP, EF, GLS, AE, and VAC, with the opposite gradient (Group 1> 2> 3) for EDV, EDVi, ESV, ESVi, SV, SVi, and LAVI values (all P<0.01). Patients in Group 3 have higher NTproBNP level and higher percentage of B-line compared to groups 1 and 2 (P<0.05). The 3 groups were similar for values of coronary flow velocity, systolic pulmonary artery pressure, and E/e’ (see table). Univariable linear regression analysis showed that NTproBNP was correlated with force (r = 0.271, p < 0.001), VAC (r = 0.194, p = 0.001), LAVI (r = 0.327, p < 0.001), LVEDV (r = -0.245, p < 0.001), LVEDVi (r = -0.261, p < 0.001), LVESVi (r = -0.190, p = 0.002) and LVESV (r = -0.187, p = 0.002) (see figure). However, multivariable linear regression analysis showed that NTproBNP was independently associated with LAVI (β= 0.211, p < 0.001) and force (β= 1.804, p = 0.002).

Conclusions

HFpEF patients present with different LV contractile phenotypes, easily identified with resting LV force and volumetric TTE. LV force is linearly correlated with cardiac natriuretic peptide levels. The dominant hemodynamic feature of hypocontractile phenotype is a preload recruitment with dilation of LV EDV and normal SV, while the hypercontractile phenotype is characterized by a small LV with reduced SV.

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