Discriminatory and prognostic value of MRI-derived myocardial work efficiency in heart failure with preserved ejection fraction: beyond global longitudinal strain
L Zhu, M LuAbstract
Background
Left ventricular (LV) global longitudinal strain (GLS) is an established diagnostic and prognostic marker in heart failure with preserved ejection fraction (HFpEF) ; however, it is sensitive to LV afterload. Pressure-volume (PV) loop analysis accounts for LV loading conditions and may provide additional insights beyond GLS into myocardial energetics and work efficiency (WE). Compared with echocardiography, MRI-derived PV loop analysis offers superior geometric accuracy and direct volumetric measurements; nevertheless, evidence supporting its clinical value in HFpEF remains limited.
Purpose
To determine the discriminatory and prognostic value of myocardial WE derived from cardiac MRI in patients with HFpEF.
Methods
Patients with suspected HFpEF who underwent cardiac MRI from August 2016 to June 2021 were consecutively enrolled. LV GLS was measured using the feature-tracking technique. PV loop analysis was performed by integrating LV myocardial strain with brachial systolic and diastolic blood pressure data. WE was calculated as stroke work (SW) divided by the sum of SW and potential energy (PE): WE = SW/(SW+PE). The primary endpoint was a composite of all-cause death and HF hospitalization.
Results
This study included 466 participants, comprising 426 patients with HFpEF (age 54.8 ± 13.9 years; 71% male) and 40 sex- and age-matched healthy controls (age 56.1 ± 7.1 years; 55% male). In multivariable logistic regression analysis, lower WE was significantly associated with higher odds of HFpEF (adjusted odds ratio per 1% decrease, 1.25 [95% CI: 1.03, 1.50; P = .022]), even after adjusting for age, sex, and GLS. In a post-hoc subgroup of patients with GLS < 20%, no significant differences in GLS were observed compared with healthy controls (P = .085). In contrast, WE in the patient subgroup was significantly lower than that in controls (P = .022). Following the exclusion of 16 patients who were lost to follow-up, 410 patients with HFpEF remained for inclusion in the outcome analysis. During a median follow-up of 3.7 years, 116 patients (28.3%) reached the primary composite endpoint (all-cause death: n=15 [3.7%] and HF hospitalization: n=105 [25.6%]). Multivariable Cox regression analysis revealed that lower WE (< 71.15%) was an independent predictor of the primary endpoint (adjusted hazard ratio, 1.73 [95% CI: 1.16, 2.58; P = .007]) after adjustment for age, prior HF hospitalization, estimated glomerular filtration rate, and extracellular volume fraction (> 28.69%), and even remained independent after the additional adjustment for GLS (P = .035).
Conclusions
WE derived from cardiac MRI provided independent discriminatory and prognostic value in patients with HFpEF, even after adjustment for GLS. Cardiac MRI-derived myocardial WE may detect more subtle energetic impairments in HFpEF at an earlier stage, providing a new dimension beyond GLS.