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.
BACKGROUND Heart failure with preserved ejection fraction (HFpEF) is a heterogeneous entity including patients with different phenotypes of near normal, normal, and supernormal left ventricular (LV) function. OBJECTIVES To assess the value of resting LV elastance (also known as force) 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. Systolic blood pressure (SBP) was measured. We assessed LV end-diastolic volume (EDV), end-systolic volume (ESV), EF, force (SBP/ESV), stroke volume (SV), arterial elastance (AE), ventricular-arterial coupling (VAC), and left atrial volume index (LAVI). Global longitudinal strain (GLS) was available in 1164 (48.9%) patients. 680 patients finished follow-up with a composite end-point of major adverse cardiac events (MACEs). Patients were divided into three groups: low force (< 25th percentile, Group 1, < 3.24 mmHg/ml), intermediate force (≥ 25th percentile and ≤ 75 th percentile, Group 2, 3.24-5.48 mmHg/ml), and high force (> 75 th percentile, Group 3, >5.48 mmHg/ml). RESULTS 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, ESV, SV, and LAVI values (all P<0.01). After a median follow-up of 16 months, 205 MACEs occurred in 138 patients. Cumulative MACEs rate was lowest in group 2 (14.7% person-year), higher in group 1 (16.1% person-year) and 3 (22.9% person-year, log rank p = 0.036). CONCLUSIONS HFpEF patients present with different LV contractile phenotypes, easily identified with resting LV force and volumetric TTE. The dominant hemodynamic feature of hypocontractile phenotype is a preload recruitment with larger LV EDV and normal SV, while the hypercontractile phenotype is characterized by a small LV with reduced SV. The hypercontractile and hypocontractile phenotypes are associated with a higher risk of subsequent events.