Use of endovascular stents for acute aortic dissection: an experimental study

This study was designed to evaluate the potential obliteration of an experimental aortic dissection using an intravascular stent introduced via the femoral artery. Twenty-two adult dogs were divided into four groups: in group A (n = 6) a thoracoabdominal aortic dissection was surgically created to observe the natural course of this lesion; in group B (n = 6) a nitinol coil graft was introduced into the aorta via the femoral artery; in group C (n = 3) a nitinol coil graft was introduced via the femoral artery into a dissected aorta in an attempt to obliterate the dissection; and in group D (n = 7) an expandable intraluminal vascular graft (Palmaz stent) was introduced via the femoral artery into a dissected aorta in an attempt to obliterate the dissection. Arteriographic evaluation was performed postoperatively and again 6 weeks later before the aortas were explanted. Gross and light microscopic examinations were performed on all explanted aortas. In group A dissection was achieved and a postoperative aortogram demonstrated evidence of aortic dissection in all animals. Autopsy revealed persistence of dissection with a reentry tear near the celiac axis in five animals. In group B there was incomplete expansion of the nitinol coil graft in five dogs, resulting in aortic thrombosis in one. In group C the nitinol coil graft failed to obliterate the aortic dissection in all animals and resulted in aortic thrombosis in two. In group D placement of a balloon-expandable intraluminal stent solely at entry and reentry sites resulted in only partial obliteration of the dissection (n = 3), but when the entire length of the dissected aorta was treated, the dissection was completely obliterated (n = 3).