Left Ventricular Outflow Indices in Chronic Systolic Heart Failure: Thresholds and Prognostic Value

Area of Science:

• Cardiology
• Echocardiography
• Heart Failure Research

Background:

• Left ventricular (LV) outflow velocity time integral (LVOT-VTI) is increasingly used for heart failure (HF) patient stratification.
• Common LV outflow indices include cardiac index (CI) and stroke volume index (SVI).

Purpose of the Study:

• To evaluate the prognostic significance of LVOT-VTI compared to CI and SVI.
• To assess the reproducibility and determine cut-off values for LVOT-VTI.

Main Methods:

• Doppler echocardiography was performed on 424 HF outpatients with LV systolic dysfunction.
• Bland-Altman analysis assessed index reproducibility.
• Cox regression and ROC analysis evaluated prognostic significance and cut-off values.
• Kaplan-Meier survival analysis assessed combined prognostic markers.

Main Results:

• LVOT-VTI demonstrated the highest reproducibility among outflow indices.
• LVOT-VTI was the most significant univariate predictor of cardiovascular death.
• LVOT-VTI < 12.0 cm was the optimal cut-off for predicting mortality (ROC analysis).
• Low LVOT-VTI correlated with reduced LV ejection fraction, elevated BNP, and high LV filling pressures.
• Combined low LVOT-VTI and low TAPSE/PASP indicated the worst prognosis.

Conclusions:

• LVOT-VTI < 12.0 cm is the best predictor of cardiovascular outcomes in HF patients with systolic dysfunction.
• LVOT-VTI is the most reproducible index of LV forward flow.
• Combining LVOT-VTI with TAPSE/PASP identifies patients with the poorest survival.