NEW ENDOVASCULAR TECHNOLOGIES TO RECONSTRUCT AORTIC ARCH IN SITU

Abstract

The aim of this chronic experimental study is to evaluate the feasibility of endovascular repair of the complete aortic arch by using novel fenestration devices and off the shelf products with simultaneous support of the cerebral circulation. The study designed to have three stages; cadaver, acute and chronic animal studies. After having satisfactory results from cadaver and acute animal studies which had proven the feasibility of the technique. Five Yorkshire pigs were used for the chronic experiments. In order to support the cerebral circulation at five chronic animal study, right femoral artery to right distal carotid artery bypass circuit was achieved during the stent graft deployment, fenestration and conduit fixation procedures. Commercially available Valiant Thoracic Stent Grafts, covered stems, steerable guiding catheters and dilatation balloons were also used during the procedure. Among the commercially available covered stents iCast had chosen because of its perfect response for proximal flairing (1,) (2). Medtronic Research and Development Department produced two prototype of fenestration devices, radio frequency (RF) plasma electrode catheter was chosen to create fenestrations at chronic study while balloon-centered needle-dilator catheter had the risk of perforation during manipulation of sharp angulated arteries (1, 2). All animals survived during the stent graft implantation, fenestration conduit implantation procedures and following 28 days. Necropsy revealed secure fixation and sealing of the conduits into the fenestrated segments of the stent graft. There were neither fractures or infoldings, proximal or distal migrations or endoleaks depending on Valiant stent graft nor collapse, crush, detachment or stenosis of covered stents. No treatment related embolic findings revealed at macroscopic and microscopic evaluation of the brain. Endovascular repair of the total aortic arch via in situ fenestration of the stent graft using cerebral circulatory support seems to be feasible and safe. Further techniques are required to complete this technique to become perfect and easy to apply complicated aortic pathologies in a short time with minimal complications. Further studies should be focused on development of off the shelf RF plasma fenestration devices and creating necessary hole diameter and than can be used as a guide wire which over it self flaring conduits can be implanted at one step are required before clinical adoption of this procedure.