Page 18 - Journal of Structural Heart Disease Volume 5, Issue 3

57 Original Scientific Article
Figure 4. Images for a 68-year-old woman with severe aortic stenosis. Ejection fraction was 59%. Panel A. On transthoracic echocar- diography, left ventricular outflow tract (LVOT) diameter was measured as 1.98 cm and LVOT area was calculated as 3.10 cm2. Aortic valve area (AVA) was measured as 0.66 cm2 by using the continuity equation. Panel B. Severe degree of aortic valve calcification on pre-contrast cardiac computed tomography (CCT) image. Agatston aortic valve score was 2,101. Panel C. The LVOT was elliptical on multiplanar reformatted CCT with an eccentricity index of 0.80 measured as the ratio of the minimum (2.11 cm)/maximum diameter (2.63 cm). Panel D. The measured LVOT area was 3.89 cm2. Panel E. CCT planimetry AVA was 0.72 cm2.
AVACCT and LVOT area measured with CCT were 0.973 (95% CI: 0.963 to 0.981) and 0.948 (95% CI: 0.927 to 0.963), respectively. Intra-class correlation coefficient for inter-observer measurements of AVACCT and LVOT area measured with CCT were 0.60 (95% CI: 0.38 to 0.74) and 0.90 (95% CI: 0.86 to 0.93), respectively.
Assessment of difference between AVACCT and AVATTE
Simple linear regression analysis showed that dif- ference between AVACCT and AVATTE was associated with age, aortic valve calcification grade (0/1 vs. 2/3), log-transformed aortic valve calcium score, transval- vular mean pressure gradient, CCT image quality, and LVOT area difference between CCT and TTE. Multiple linear regression analysis revealed that the following three variables were significantly associated with dif- ference between AVACCT and AVATTE: log-transformed aortic valve calcium score (inverse relationship), LVOT area difference between CCT and TTE, and age (in- verse relationship) in decreasing order of significance
(Table 3). On subgroup analysis, AVAs measured with CCT were not correlated with AVA by TTE in group with LVEF < 50%, aortic valve calcium score > 1,651, LVOT eccentricity ≥ 0.78, presence of AF, absence or mild grade of aortic valve calcification, or transvalvu- lar pressure gradient ≤ 40 mmHg (Table 4).
Discussion
This study demonstrated that a discrepancy be- tween CCT and TTE measurements of AVA that was significantly associated with log-transformed Agat- ston aortic valve score, LVOT area difference mea- sured with CCT and TTE, and age in patients with severe AS. However, LVOT eccentricity and aortic an- nular calcification severity were not associated with difference between AVACCT and AVATTE.
The hemodynamic (AVATTE) and anatomic (AVACCT) AVA are not interchangeable. Our result was consis- tent with previous studies showing that continuity
Ko S. M. et al.
Aortic Valve Area Measured with CT and TTE