Enlarged Size and Impaired Elastic Properties of the Ascending Aorta are Associated with Endothelial Dysfunction and Elevated Plasma Matrix Metalloproteinase-2 Level in Patients with Bicuspid Aortic Valve.

The aim of this study was to test whether enlarged size and impaired elastic properties of the ascending aorta are associated with impaired endothelial function and increases in plasma matrix metalloproteinase (MMP)-2 concentrations in patients with bicuspid aortic valve (BAV) without significant valvular dysfunction. The size and the elasticity of the ascending aorta and the flow-mediated vasodilation (FMD) in the brachial artery in response to hyperemia were evaluated with 2-D echocardiography and high-frequency linear ultrasound in 42 patients with BAV without significant valvular dysfunction and 30 age- and sex-matched healthy controls. In the BAV group, diastolic ascending aortic diameter (AoD) (32.1 ± 8.1 mm vs. 25.3 ± 3.6 mm, p <0.001) and aortic stiffness index (8.0 ± 5.3 vs. 4.0 ± 1.8, p <0.001) were significantly higher, and aortic strain (7.4 ± 3.6% vs. 11.1 ± 3.0%, p <0.001) and aortic distensibility (7.4 ± 4.1 × 10cm/dyn vs. 11.1 ± 4.3 × 10cm/dyn, p <0.001) were significantly lower than those in the control group. The BAV group also had lower FMD (6.5 ± 2.2% vs. 11.9 ± 2.7%, p <0.001) and higher plasma MMP-2 levels (226.7 ± 55.0 ng/mL vs. 177.0 ± 45.3 ng/mL, p <0.001) compared with the control group. In the BAV group, AoD, aortic strain, aortic stiffness index and aortic distensibility significantly correlated with FMD and MMP-2 (all p <0.05). The multivariable linear regression analysis further indicated that FMD and MMP-2 were independently associated with AoD (β = -1.1, p = 0.005, and β = 0.09, p <0.001, respectively). These findings suggest that enlarged size and impaired elastic properties of the ascending aorta are associated with endothelial dysfunction and elevated plasma MMP-2 level in patients with BAV without significant valvular dysfunction. FMD and plasma MMP-2 level are the significant and independent predictors of dilation of the ascending aorta in patients with BAV.