oa Distensibility of Decellularized and Glutaraldehyde-Preserved Aortic Full Roots as Evaluated by Computed Tomography

The aortic root is a dynamic structure and its distensibility is considered an important factor in native and prosthetic heart valve function. Glutaraldehyde-preserved (GLUT) valves have limited durability possibly due to increased tissue stiffening. Decellularized deoxycholic acid-treated (DOA) valves exhibit excellent long-term performance in the pulmonary position in humans possibly due to preservation of valve tissue distensibility. We investigated aortic distensibility in DOA (n=8) and GLUT (n=3) aortic root prostheses in 60 kg pigs 2 weeks after orthotopic implantation. Five pigs served as controls. Using a dual source computed tomography scanner (Somatom Flash, Siemens Medical Solution, Forcheim, Germany) the cross sectional area at the level of Sinus of Valsalva (SoV), sino-tubular junction (STJ), and ascending aorta (AA), respectively, was measured in both diastole and systole. Distensibility was defined as the change in area from diastole (RR 95%) to systole (RR 15%). For assessment of the prosthetic- independent aortic distensibility we performed the same measurements in the descending aorta (AD) in all animals. Data were analyzed using students t-test and reported as a mean±SD. Native aortic distensibility was significant larger at the level of SoV (15.8%±4.9), STJ (46.7%±10.3), and AA (40.6%±9.0), compared with both DOA and GLUT aortic roots (p<0.05). No difference in distensibility between the DOA and GLUT aortic roots were observed: 8.8%±2.4 vs 6.2%±5.5 (SoV), 11.7%±3.0 vs 10.0%±7.1 (STJ), 14.9%±6.1 vs 11.8±1.7 (AA), and 15.6±1.5 vs 15.5±1.8 (DA) , respectively (p>0.05). There was no difference in mean distensibility between the three groups in the decending aorta. This is the first study to evaluate in-vivo distensibility of aortic root prostheses in vivo. Aortic root distensibility is reduced following implantation of DOA or GLUT prosthetic aortic valves. No difference was observed between DOA and GLUT valves. Long-term follow-up is needed in order to verify any changes in bioprosthetic aortic root distensibility over time.