Biomechanical study on ascending aortic aneurysms associated with quadricuspid aortic valve

Abstract

The quadricuspid aortic valve (QAV) is a rare anatomical situation and the biomechanical properties are not well known when it is associated with ascending aortic aneurysms (AsAA). The objective is to find out what is the biomechanical properties in such situation and to compare it with the existing data. In a sixty-three-years-old female (BMI 26,4) with hypertension disease, QAV, AsAA of 52 mm, an aortic valve and ascending aorta replacement were performed. The aortic wall sample was collected within 30 mins after replacement, partitioned related to medial, posterior, lateral, and anterior quadrants. The sample was cut in square size (15 mm × 15 mm, n = 13) with marking the circumferential and longitudinal directions. An average thickness was measured, using an electronic micrometer (Litematic VL-50, Mitutoyo®). The experiments were carried out by a biaxial tensile test machine (ElectroForce®). Each specimen was stretched at a rate of 10 mm/min until rupture. Maximum Elastic Modulus was calculated for each specimen. The CFD simulation was carried out by ANSYS® R1 2019, with the input of inlet measured in MRI sequence. The longitudinal direction of the aorta is stiffer than the circumferential direction except in the medial quadrant in both tissue types. The lateral quadrant of the aorta shows a higher stiffness (0.672 MPa), the double value of the medial quadrant (0.308 MPa). This result matches our previous study of AsAA on the bicuspid aortic valve. In the CFD simulation, it shows a higher velocity in the laterial quadrant of the acsending aorta near the aortic arch ( Fig. 1 ). In this study, the aortic biomechanical properties are similar regardless of quadricuspid or bicuspid aortic valve.