ENDOVASCULAR GRAFT FOR REPAIRING ABDOMINAL AORTIC ANEURYSMS

摘要

This is regarding a type of device aimed at a simpler, in relation to already existing techniques, endovascular positioning of a stent-graft in the abdominal aorta for the therapy of aneurysms up to the point of its bifurcation (26). This device is comprised of a system of three cylinders: a "main" (1) centrally placed and two "limbs" (4, 5) peripherally placed. Each of these cylinders has a central (14, 9, 8) and a peripheral (12, 10, 11) orifice. The cylinders are comprised of a cylindrical metallic skeleton which is self-expanding (2, 7) and made out of stainless steel or nitinol and which is externally covered with a cylinder (3, 8) made out of thin-layered PTFE, Dacron or some other elastic biocompatible material, refolded (18) around the peripheral orifice (12) of the skeleton of the main cylinder. These cylinders can be compressed into small diameter tubules (23, 27, 38) and enter the vascular lumen. After their insertion into the desired position, they expand, regaining their original diameter. The main cylinder (1) is placed inside the aorta becoming more circular when it comes in contact with the healthy part of the aorta (13) central to the aneurysm at the center of the orifice (14). The peripheral orifice of the main cylinder sits upon the expanded aortic bifurcation (26). The two limbs have a central orifice (8, 9) with a diameter equal to or approximately about 2 mm smaller than the diameter of the peripheral orifice (12) of the main cylinder. The branching of the main cylinder is accomplished by the entrance of the main ends of the two limbs inside the peripheral end of the main cylinder. Both limbs are at the same height in such a manner that they compress each other at the center of the cylinder. Each limb exerts equal pressure, whereas equal pressure is also exerted on the internal surface of the main cylinder from their external surface (FIG. 5) and together they both occupy at the height of their orifices the entire perimeter of the main cylinder (43). Alternatively, as limbs (peripheral cylinders), tubes of different diameters and types of skeletons can be used (28, 27).