Impairment in Aortic Elastic Properties and Mechanics of Ascending Aorta in Patients with Bicuspid Aortic Valve

Background: Bicuspid aortic valve (BAV), which is one of the most common congenital heart defects, is a genetic disorder of the aortic valve and ascending aorta. Aortic dilation is common in subjects with BAV. In the present study we aimed to investigate the elastic and mechanical properties of the aorta by using a novel strain imaging method, "velocity vector imaging" (VVI), in patients with BAV. Methods: We studied 22 patients with BAV (age 43.31±4.5, 57% female) and 20 age and sex-matched healthy subjects with tricuspid aortic valve. All the patients and healthy controls were subjected to assessment of aortic strain, stiffness and distensibility measurements of M-mode images of the aorta. VVI measurements were obtained from off-line analysis of standard B-mode ultrasound images of the ascending aorta. Results: Aortic strain (5.2±1.5% to 13.91±4.77%, respectively, p=0.0001), and distensibility 0.19±0.06% to 1.6±0.77%, respectively, p=0.0001) were significantly impaired in patients with BAV, compared to the control group. Aortic stiffness was markedly increased in patients with BAV (4.45±1.73 to 2.6±1.3, respectively, p=0.001).Regarding VVI-based strain measurements, peak longitudinal strain (S), strain rate (SR) and total longitudinal displacement (TLD) values were significantly impaired in patients with BAV, compared to the controls. (S: 11.49±1.2% to 14.6±2.58%, p=0.03; SR: 0.57±0.03 1/s to 1.66±0.40 1/s, p=0.0001; TLD: 3.98±1.78 mm to 10.42±2.38 mm, p= 0.0001). Conclusions: BAV is associated with reduced elasticity of the aorta. Longitudinal wall motion of ascending aorta is also impaired in patients with BAV. VVI is a novel strain imaging method which provides detailed data in assessing the longitudinal deformation of the ascending aorta, in patients with BAV.