The feasibility of velocity vector imaging by transesophageal echocardiography for assessment of elastic properties of the descending aorta in aortic valve disease

Abstract

Background: Velocity vector imaging (VVI) is a novel two-dimensional speckle-based imaging technique for evaluation of tissue deformation. The aim of this study was to determine the feasibility and variability of VVI for the assessment of aortic strain, distensibility, and stiffness in patients with aortic valve disease.

Method: Eighty-five patients (mean age 66 +/- 11 years) with aortic stenosis (AS) or aortic regurgitation (AR) were examined in the operating room before the operation using transesophageal echocardiography (TEE). The two-dimensional short-axis images and M-mode recordings of the descending aorta were acquired simultaneously with the invasive blood pressure measurement in the radial artery. The TEE images were analyzed off-line using VVI software.

Results: In comparison with patients with AS, patients with AR displayed significantly higher circumferential strain (7.6% +/- 4.5% vs. 3.7% +/- 1.9%, P < .001) and distensibility (27.1 +/- 12.8 kPa(-1)10(-3) vs. 17.2 +/- 7.2 kPa(-1)10(-3), P < .001) by VVI and distensibility (32.8 +/- 16.7 kPa(-1)10(-3) vs. 21.7 +/- 10.6 kPa(-1)10(-3), P < .004) by M-mode. Stiffness was higher in AS than AR, as measured by VVI (13.3 +/- 6.0 vs. 10.5 +/- 6.0, P < .01) and M-mode (11.2 +/- 6.1 vs. 10.4 +/- 9.1, P < .048). The correlations between VVI and M-mode distensibility (r = 0.84) and stiffness (r = 0.84) were both highly significant (P < .0001). The VVI strain measurements showed low inter- and intraobserver variability with intraclass correlations greater than 0.95 and coefficients of variation less than 10%.

Conclusion: VVI-derived strain, distensibility, and stiffness differ significantly between AR and AS and correlate strongly with the corresponding M-mode-derived parameters. VVI is a feasible method for the assessment of the elastic properties of the descending aorta with low variability and has the advantage of incorporating the entire aortic wall circumference in the analysis, consequently accounting for local variations in the elastic properties of the aorta.