Incremental Prognostic Value of Assessing Left Ventricular Myocardial Mechanics in Patients With Chronic Systolic Heart Failure

Abstract

This study sought to examine the ability of left ventricular (LV) global longitudinal strain (GLS) to assess disease severity in patients with chronic systolic heart failure (HF). Left ventricular GLS is a sensitive measure of LV mechanics. Its relationship with standard clinical markers and long-term adverse events in chronic systolic HF is not well established. In 194 chronic systolic HF patients, we performed comprehensive echocardiography with assessment of GLS by velocity vector imaging averaged from apical 4-chamber and 2-chamber views. Death, cardiac transplantation, and HF hospitalization were tracked for 5 years. In our study cohort (age 57 ± 14 years, left ventricular ejection fraction [LVEF] 26 ± 6%, median N-terminal pro-B-type natriuretic peptide [NT-proBNP] 1,158 pg/ml), the mean GLS was -7.1 ± 3.3%. The GLS worsened with increasing New York Heart Association functional class (rank-sum p < 0.0001) and higher NT-proBNP (r = 0.42, p < 0.0001). The GLS correlated with LV cardiac structure (LV mass index: r = 0.35, p < 0.0001; LV end-diastolic volume index: r = 0.43, p < 0.0001) and LVEF (r = -0.66, p < 0.0001). A lower magnitude of GLS was associated with worsening LV diastolic function (E/e' septal: r = 0.33, p < 0.0001), right ventricular (RV) systolic function (RV s': r = -0.30, p < 0.0001), and RV diastolic function (RV e'/a': r = 0.16, p = 0.033). GLS predicted long-term adverse events (hazard ratio: 1.55, 95% confidence interval: 1.21 to 2.00; p < 0.001). Worsening strain (GLS ≥-6.95%) predicted adverse events after adjustment for age, sex, ischemic etiology, E/e' septal, and NT-proBNP (hazard ratio: 2.04, 95% confidence interval: 1.09 to 3.94; p = 0.025) and age, sex, ischemic etiology, and LVEF (hazard ratio: 2.15, 95% confidence interval: 1.19 to 4.02; p = 0.011). In chronic systolic HF, worsening LV GLS is associated with more severe LV diastolic dysfunction and RV systolic and diastolic dysfunction, and provides incremental prognostic value to LVEF.