Objective: Transluminal endovascular grafting (TEG) is less invasive than conventional operative procedures for the treatment of DeBakey type III dissecting aortic aneurysms (DAA). We have used two different kinds of stent grafts covered with woven Dacron grafts, a Gianturco Z-stent graft (G-SG) and a Spiral Z-stent graft (S-SG). Because the G-SG lacks adequate flexibility, the end of the graft may injure the intima after long-term deployment in the proximal descending aorta. We have used S-SGs, which are more flexible than G-SG, to improve outcome. We report our late midterm results and discuss treatment policy.
Subjects and methods: We studied 45 patients with DeBakey type III DAA. Thirty-two G-SGs and 13 S-SGs were used. Follow-up ranged from 1 year 6 months to 8 years 5 months (mean, 5 years 2 months).
Results: 1) Surgical outcome: (a) TEG was technically successful in all patients. There was no operative mortality. (b) One week after surgery, 36 patients had no endoleaks, 5 had minor endoleaks, and 4 had major endoleaks. 2) Late midterm results: (a) Four patients with residual major endoleaks, underwent replacement of the descending thoracic aorta. (b) Intimal injury occurred at the distal end of the stent graft 4 to 18 months (mean, 10.5 months) after surgery in 12 patients with G-SG and 1 with S-SG. One of these patients had recurrent dissection, and 12 had ulcer like projections (ULP). Two patients underwent additional stent implantation to block blood flow. (c) Four patients with S-SG had major endoleaks 3 to 6 months after surgery. In 3 of these patients, the Spiral Z-stents were compressed and occluded, and thrombus had formed in the lumen. Three patients underwent replacement of the descending thoracic aorta. (d) Additional replacement of the descending thoracic aorta was done in 9 of the 45 patients (20%) 4 to 24 months after TEG. All patients responded to treatment and were discharged from the hospital.
Conclusion: Intimal injury was caused by Gianturco Z-stents because of inadequate flexibility, and endoleaks and stent-graft occlusion were caused by Spiral Z-stents because of insufficient radial force against the aortic wall. The development of stents with these improved properties is expected to further improve outcome.