• cardiac index
• cardiac output
• stroke volume
• ejection fraction
• LVOT-VTI
• systolic function
• heart failure

Background and Aims: Though widely used to classify heart failure (HF) patients, the prognostic role of left ventricular ejection fraction (LVEF) is debated. We hypothesized that the echocardiographic measures of forward LV output, being more representative of cardiac hemodynamics, may improve risk prediction over LVEF in a large cohort of HF patients with systolic dysfunction.
Methods: Consecutive HF patients with LVEF <50% on guideline-recommended therapies undergoing an echocardiography including the evaluation of forward LV output (i.e., LV outflow tract velocity-time integral [LVOT-VTI], stroke volume index [SVi], and cardiac index [CI]) over a 6-year period, were selected and followed-up for the endpoint of cardiac and all-cause death.
Results: Among the 1,509 patients analyzed (71±12 years, 75% males, LVEF 35±9%), 328 (22%) died during a median 28-month (14-40) follow-up, 165 (11%) of which for cardiac causes. At multivariable regression analysis, LVOT-VTI (<0.001), SVi (p<0.001), and CI (p<0.001), but not LVEF (p>0.05), predicted cardiac and all-cause death. The optimal prognostic cut-offs for LVOT-VTI, SVi, and CI were 15 cm, 35 mL/m2, and 2.3 L/min/m2, respectively. Adding each of these measures to a multivariable risk model (including clinical, biohumoral, and echocardiographic markers) improved risk prediction (Chi-square 212 vs. 188, p<0.001). Among the different measures of forward LV output, LVOT-VTI and SVi were more accurate than CI (Chi-square 212 vs.204, p<0.001).
Conclusion: The echocardiographic evaluation of forward LV output improves risk prediction in HF patients across a wide LVEF spectrum over other well-established clinical, biohumoral, and echocardiographic prognostic markers.