Left Ventricular Elastance With Resting Volumetric Transthoracic Echocardiography Identifies Different Phenotypes in Heart Failure With Preserved Ejection Fraction: A Retrospective Analysis of a Multicenter Prospective Observational Study

Abstract

Background: Heart failure with preserved ejection fraction (HFpEF) is a heterogeneous entity including different phenotypes of near normal, normal, and supernormal left ventricular (LV) function. The aim of this study was to assess the value of resting LV elastance (also known as force) using transthoracic echocardiography to identify HFpEF phenotypes. Methods: In a prospective, observational, multicenter study, 2,380 patients with HFpEF were recruited from July 2016 to May 2024. Systolic blood pressure (SBP) was measured. LV end-diastolic volume (LVEDV), LV end-systolic volume (LVESV), LV ejection fraction, force (SBP/LVESV), stroke volume (SV), arterial elastance, ventricular-arterial coupling, and left atrial volume index were assessed. Global longitudinal strain was available in 1,164 patients (48.9%). Six hundred eighty patients finished follow-up with a composite endpoint of major adverse cardiac events (MACEs). Patients were divided into three groups: group 1, low force (<25th percentile, <3.24 mm Hg/mL); group 2, intermediate force (≥25th percentile and ≤75th percentile, 3.24-5.48 mm Hg/mL); and group 3, high force (>75th percentile, >5.48 mmHg/mL). Results: The three groups showed a gradient with descending values (group 3 > group 2 > group 1) for SBP, LV ejection fraction, global longitudinal strain, arterial elastance, and ventricular-arterial coupling, with the opposite gradient (group 1 > group 2 > group 3) for LVEDV, LVESV, SV, and left atrial volume index values (P < .01 for all). After a median follow-up period of 16 months, 205 MACEs occurred in 138 patients. The cumulative MACE rate was lowest in group 2 (14.7% person-years) and higher in groups 1 (16.1% person-years) and 3 (22.9% person-years; log-rank P = .036). Conclusions: Patients with HFpEF present with different LV contractile phenotypes, easily identified with resting LV force and volumetric transthoracic echocardiography. The dominant hemodynamic feature of hypocontractile phenotype is a preload recruitment with larger LVEDV and normal SV, while the hypercontractile phenotype is characterized by a small left ventricle with reduced SV. The hypercontractile and hypocontractile phenotypes are associated with a higher risk for subsequent events.