Technical Development and Initial Animal Experience With a Novel, Uncovered, Self-Expanding, Highly Flexible Aortic Stent With Improved Side Branch Access

Abstract

To present a novel, uncovered, self-expanding aortic stent for use as a thoracoabdominal stent-graft extension to improve distal flow in aortic dissections complicated by malperfusion syndrome and to enhance the remodeling process in the abdominal aorta after thoracic endovascular aortic repair. This aortic prosthesis is a laser cut, self-expanding nitinol stent that is designed to provide an optimal balance between radial support and flexibility to negotiate tortuous arterial anatomy. Undulating circumferential rings provide radial force, while flexibility is achieved through the shape and configuration of the longitudinal connectors that extend from the valley of one ring to the offset peak of the next ring. Delivery and deployment characteristics, in vivo flexibility of the stent, and side branch accessibility through the bare stent struts were evaluated in 4 anesthetized domestic swine weighing 68 to 73 kg. All 11 attempted stent implantations were successful in the 4 pigs using a retrograde transiliac access. The stents were positioned and deployed exactly at the intended target locations and conformed well to the aortic anatomy, even in the tortuous aortic arch, with no evidence of stent kinking or collapse. Overall, 21 major aortic side branches were intentionally covered with the bare stent struts; perfusion was not impaired in any branch vessel. Superselective catheterization of the side branches with coronary guiding catheters through the stent struts was possible for all vessels, as was side branch stenting in 3/3 attempts. This initial feasibility study demonstrates the ability to deploy this novel self-expanding aortic stent in pigs. The high flexibility of the stent allowed conformability with tortuous aortic anatomy. Access to side branches overstented with bare stent struts was excellent. Clinical evaluation of the device is planned for the near future.