Abstract 4284: An Expansible Aortic Ring For A Physiological Approach Of Aortic Valve Repair
Objectives: Dystrophic aortic insufficiency is characterized by dilatation of the aortic annular base and sinotubular junction (STJ) diameters with thin and pliable cusps amenable to valve repair. An expansible aortic ring was designed to reduce aortic root diameters in order to increase valvular coaptation height while maintaining root dynamics. The biocompatibility and function of the device was tested in vivo on an ovine model.
Methods: Expansible rings were composed of an elastomer core covered by knit polyester fabric. After in vitro analysis of their mechanical properties, expansible rings were implanted in 6 sheep at the level of the aortic annular base and STJ (double sub and supra-valvular external aortic annuloplasty). Aortic root dynamics were assessed using intracardiac echography before surgery and at 6 months. Histological, scanning electron microscopy (SEM) and mechanical studies were then performed on explanted samples.
Results: Six months after implantation the expansible ring maintained significant reduction of aortic annular base and STJ diameters. Coaptation height was increased from 2.6 ± 0.03 mm preoperative to 6 ± 0.09 mm (p<0.001). Dynamics of the aortic root were well preserved (table⇓). Morphological and histological studies showed good incorporation of the material into surrounding tissue and the absence of calcification. Implanted ring SEM examinations showed no evidence of material degradation after 6 months. Mechanical testing of the device before and after implantation show no significant differences (p>0.05) in elastic modulus.
Conclusion: Expansible aortic rings implantation realizes a significant annuloplasty increasing coaptation height while preserving dynamics of the aortic root on a normal ovine model. The effectiveness of the device in treating aortic insufficiency is currently being evaluated in the prospective CAVIAAR trial comparing aortic valve repair to mechanical valve replacement.