Echocardiography-Derived Forward Left Ventricular Output Improves Risk Prediction in Systolic Heart Failure
Francesco Gentile1, Paolo Sciarrone2, Giorgia Panichella1
1Health Science Interdisciplinary Center, Scuola Superiore Sant'Anna, Pisa, Italy.
Insights
Forward left ventricular (LV) output measures, such as LV outflow tract velocity-time integral and stroke volume index, better predict heart failure (HF) mortality than ejection fraction. These hemodynamic markers improve risk stratification in HF patients.
Area of Science:
- Cardiology
- Echocardiography
- Heart Failure Research
Background:
- Left ventricular ejection fraction (LVEF) is a standard but debated prognostic marker in heart failure (HF).
- Echocardiographic measures of forward left ventricular (LV) output may offer superior hemodynamic representation for risk prediction.
Purpose of the Study:
- To evaluate if echocardiographic forward LV output metrics improve risk prediction in HF patients with systolic dysfunction.
- To compare the prognostic value of forward LV output measures against LVEF.
Main Methods:
- Analysis of 1,509 stable HF patients with LVEF <50% on optimal therapy.
- Echocardiographic assessment of LV outflow tract velocity-time integral (VTI), stroke volume index (SVi), and cardiac index.
- Follow-up for cardiac and all-cause death over a median of 28 months.
Main Results:
- Forward LV output measures (LVOT VTI, SVi, cardiac index) significantly predicted mortality (P < .001), unlike LVEF (P > .05).
- Optimal cutoffs identified: LVOT VTI 15 cm, SVi 38 mL/m², cardiac index 2 L/min/m².
- Incorporating these measures into risk models significantly improved prediction (P < .001).
Conclusions:
- Echocardiographic forward LV output evaluation enhances risk prediction in HF patients across diverse LVEF.
- These hemodynamic measures surpass traditional clinical, biohumoral, and echocardiographic markers for prognosis.
Background:
Although it is widely used to classify patients with heart failure (HF), the prognostic role of left ventricular ejection fraction (LVEF) is debated. The aim of this study was to test the hypothesis that echocardiographic measures of forward left ventricular (LV) output, being more representative of cardiac hemodynamics, might improve risk prediction in a large cohort of patients with HF with systolic dysfunction.
Methods:
Consecutive stable patients with HF with LVEF <50% on guideline-recommended therapies undergoing echocardiography including the evaluation of forward LV output (i.e., LV outflow tract [LVOT] velocity-time integral [VTI], stroke volume index [SVi], and cardiac index) over a 6-year period were selected and followed for the end point of cardiac and all-cause death.
Results:
Among the 1,509 patients analyzed (mean age, 71 ± 12 years; 75% men; mean LVEF, 35 ± 9%), 328 (22%) died during a median follow-up period of 28 months (interquartile range, 14-40 months), 165 (11%) of cardiac causes. On multivariable regression analysis, LVOT VTI (P < .001), SVi (P < .001), and cardiac index (P < .001), but not LVEF (P > .05), predicted cardiac and all-cause death. The optimal prognostic cutoffs for LVOT VTI, SVi, and cardiac index were 15 cm, 38 mL/m2, and 2 L/min/m2, respectively. Adding each of these measures to a multivariable risk model (including clinical, biohumoral, and echocardiographic markers) improved risk prediction (P < .001). Among the different measures of forward LV output, cardiac index was less accurate than LVOT VTI and SVi.
Conclusions:
The echocardiographic evaluation of forward LV output improves risk prediction in patients with HF across a wide LVEF spectrum over other well-established clinical, biohumoral, and echocardiographic prognostic markers.
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