Discriminative Ability of Left Ventricular Strain in Mildly Reduced Ejection Fraction Heart Failure

Background: Left ventricular (LV) systolic strain is presumably a more sensitive myocardial indicator than LV ejection fraction (LVEF). Data regarding the use of LV strain in clinical risk stratification and in identifying angiotensin receptor-neprilysin inhibitor (ARNi) responders remain scarce in heart failure with mildly reduced ejection fraction (HFmrEF). Objectives: The authors aimed to examine whether assessing LV strain may provide prognostic insight beyond LVEF and help discriminate the therapeutic efficacy of ARNi in HFmrEF patients. Methods: LVEF and LV strain were quantified among 1,075 first-time hospitalized HFmrEF patients (mean age: 68.1 ± 15.1 years, 40% female). The MAGGIC (Meta-analysis Global Group in Chronic Heart Failure) risk score and its components were calculated. A Cox proportional hazard model was constructed for time-to-event analysis. Restrictive cubic spline curves were used to model the therapeutic effects of ARNi against renin-angiotensin system inhibitor according to baseline LVEF or LV strain. Results: LV strain showed a statistically significant inverse association with MAGGIC cardiac risk (coefficient: −0.14, P < 0.001). LV strain was independently associated with clinical outcomes after accounting for LVEF. MAGGIC-LV strain strata outperformed MAGGIC-LVEF strata in overall survival (Harrell's C-index: 0.71 and 0.56, P for difference <0.001; category-free net reclassification index: 0.44, P < 0.001). Lower LV strain but not LVEF consistently showed the beneficial therapeutic effects of ARNi against renin-angiotensin system inhibitor by Cox models and restrictive cubic spline (all Pinteraction <0.05). Conclusions: Among HFmrEF patients, LV strain may serve as an attractive systolic marker and provide a better prognostic and therapeutic discriminative measure for ARNi treatment than conventional LVEF.