The prognostic role of global longitudinal strain in heart failure: exploring beyond ejection fraction

Abstract Background Heart failure (HF) guidelines primarily rely on left ventricular ejection fraction (LVEF) to classify patients and guide therapy implementation. However, LVEF alone may be insufficient to adequately characterize patients with HF, particularly those with HF with preserved ejection fraction (HFpEF). There is a growing need to advance cardiac imaging, especially echocardiography, to improve the phenotypic and prognostic characterization of HF, ultimately guiding more precise therapy and follow-up strategies. LV global longitudinal strain (GLS), which directly reflects the motion of the myocardium, is believed to provide a better assessment of myocardial function. Purpose We aim to explore whether LV GLS predicts adverse clinical cardiovascular outcomes. Methods In this retrospective cohort study, patients diagnosed with HFmrEF/HFpEF (defined as LVEF ≥40%), according to the HFA–PEFF diagnostic algorithm, were included. Exclusion criteria inlcuded primary valvular disease, any prior LVEF <40%, infiltrative and hypertrophic cardiomyopathy, congenital heart disease, isolated right HF, and inadequate image quality for strain analysis. The primary outcome was a composite of cardiovascular mortality, HF hospitalization and HF-related emergency visits. The secondary outcomes included the evolution of NYHA functional class, diuretic dosage, and NT-proBNP levels. A time-to-event analysis was conducted, incorporating Kaplan-Meier analysis and Cox proportional hazard models. Results During a median follow-up of 11 months [IQR 7.25, 11], 15 patients developed the primary outcome, comprising 9 HF hospitalisations and one cardiovascular death. In univariable Cox regression analysis, neither LV GLS (HR=1.09, [95% CI, 0.92-1.30], p=0.3) nor LVEF (HR=0.95, [95% CI, 0.88-1.03], p=0.2) was associated with a higher risk of the primary outcome. When considering HF hospitalisations alone, LV GLS was not associated with an increased risk of HF hospitalisation (HR=1.26, [95% CI, 0.99-1.60], p=0.064). When combining LVEF and GLS, while examining the Kaplan-Meier curves, neither subgroup had a higher risk of the composite endpoint (log-rank test p=0.31, Figure 1). In comparison to stable patients, those whose NYHA functional class worsened during follow-up exhibited significantly worse baseline GLS (p=0.025), but no association was found with diuretic dose (p=0.14). Conclusions In this cohort of HFmrEF/HFpEF patients, although a large proportion exhibited impaired myocardial function by GLS, LV global longitudinal strain was not associated with cardiovascular mortality, HF hospitalizations, or HF-related emergency visits.Univariable Cox regression Kaplan-Meier curves