April 27, 2022Frontiers in Cardiovascular MedicineOpen Access

Left Heart Chamber Volumetric Assessment by Automated Three-Dimensional Echocardiography in Heart Transplant Recipients

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Why the study?

To verify the feasibility and accuracy of a new automated 3D echocardiographic algorithm (Heart Model) for measuring left heart chamber volumes in heart transplant patients.

Does automated 3D echocardiography accurately measure left heart chamber volumes and LVEF compared to manual 3DE and CMR in heart transplant recipients?

Structured PICO

Does automated 3D echocardiography accurately measure left heart chamber volumes and LVEF compared to manual 3DE and CMR in heart transplant recipients?

Population

103 healthy heart transplant (HTx) patients enrolled prospectively.

Intervention

Automated three-dimensional echocardiography (3DE) using Heart Model software.

Comparator

Conventional manual 3D transthoracic echocardiographic (TTE) tracings (Protocol 1) and cardiac magnetic resonance (CMR) images (Protocol 2, n=28).

Outcome

Feasibility and accuracy of automated 3DE for measuring left ventricular end-diastolic volume (LVEDV), LV end-systolic volume (LVESV), left atrial max volume (LAVmax), LA minimum volume (LAVmin) and LV ejection fraction (LVEF).surrogate

Automated 3D echocardiography is feasible and rapid for quantifying left heart volumes in heart transplant recipients, though only LVEDV and LAVmax with contour edit show clinically acceptable agreement with CMR.

Implication

Should not yet change HTx surveillance practice; leaves open whether contour-edited automated 3DE can replace manual methods or CMR.

Abstract

Background Recently, a new automated software (Heart Model) was developed to obtain three-dimensional (3D) left heart chamber volumes. The aim of this study was to verify the feasibility and accuracy of the automated 3D echocardiographic algorithm in heart transplant (HTx) patients. Conventional manual 3D transthoracic echocardiographic (TTE) tracings and cardiac magnetic resonance (CMR) images were used as a reference for comparison. Methods This study enrolled 103 healthy HTx patients prospectively. In protocol 1, left ventricular end-diastolic volume (LVEDV), LV end-systolic volume (LVESV), left atrial max volume (LAVmax), LA minimum volume (LAVmin) and LV ejection fraction (LVEF) were obtained using the automated 3D echocardiography (3DE) and compared with corresponding values obtained through the manual 3DE. In protocol 2, 28 patients’ automated 3DE measurements were compared with CMR reference values. The impacts of contour edit and surgical technique were also tested. Results Heart Model was feasible in 97.1% of the data sets. In protocol 1, there was strong correlation between 3DE and manual 3DE for all the parameters ( r = 0.77 to 0.96, p<0.01). Compared to values obtained through manual measurements, LV volumes and LVEF were overestimated by the automated algorithm and LA volumes were underestimated. All the biases were small except for that of LAVmin. After contour adjustment, the biases reduced and all the limits of agreement were clinically acceptable. In protocol 2, the correlations for LV and LA volumes were strong between automated 3DE with contour edit and CMR ( r = 0.74 to 0.93, p<0.01) but correlation for LVEF remained moderate ( r = 0.65, p < 0.01). Automated 3DE overestimated LV volumes but underestimated LVEF and LA volumes compared with CMR. The limits of agreement were clinically acceptable only for LVEDV and LAVmax. Conclusion Simultaneous quantification of left heart volumes and LVEF with the automated Heart Model program is rapid, feasible and to a great degree it is accurate in HTx recipients. Nevertheless, only LVEDV and LAVmax measured by automated 3DE with contour edit seem applicable for clinical practice when compared with CMR. Automated 3DE for HTx recipients is a worthy attempt, though further verification and optimization are needed.