Calculation of Aortic VAlve and LVOT Areas by a Modified Continuity Equation Using Different Echocardiography Methods: The CAVALIER Study

Overview

Journal Diagnostics (Basel)

Specialty Radiology

Date 2022 Jul 27

PMID 35885559

Authors

Tobias Friedrich Ruf

Beatrice Elise Cannard

Ruth H Strasser

Axel Linke

Krunoslav M Sveric

Affiliations

Soon will be listed here.

Abstract

Background: The area of the left ventricular outflow tract (A) represents a major component of the continuity equation (CE), which is, i.a., crucial to calculate the aortic valve (AV) area (A). The A is typically calculated using 2D echo assessments as the measured anterior-posterior (a/p) extension, assuming a round LVOT base. Anatomically, however, usually an elliptical shape of the LVOT base is present, with the long diameter extending from the medial-lateral axis (m/l), which is not recognized by two-dimensional (2D) echocardiography.

Objective: We aimed to compare standard and three-dimensional (3D)-echocardiography-derived A calculation and its use in a standard CE (CE) and a modified CE (CE) to calculate the A vs. computed tomography (CT) multi-planar reconstruction (MPR) measurements of the anatomical A and A, respectively.

Methods: Patients were selected if 3D transthoracic echocardiography (TTE), 3D transesophageal echocardiography (TEE), and cardiac CT were all performed, and imaging quality was adequate. The A was assessed using 2D calculation, (a/p only), 3D-volume MPR, and 3D-biplane calculation (a/p and m/l). A was measured using both CE and CE, and 3D-volume MPR. Data were compared to corresponding CT analyses.

Results: From 2017 to 2018, 107 consecutive patients with complete and adequate imaging data were included. The calculated A was smaller when assessed by 2D- compared to both 3D-volume MPR and 3D-biplane calculation. Calculated A was correspondingly smaller in CE compared to CE or 3D-volume MPR. The A and A, using data from 3D echocardiography, highly correlated and were congruent with corresponding measurements in CT.

Conclusion: Due to the elliptic shape of the LVOT, use of measurements and calculations based on 2D echocardiography systematically underestimates the A and dependent areas, such as the A. Anatomically correct assessment can be achieved using 3D echocardiography and adapted calculations, such as CE.

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