Aortic stent-grafting with transrenal fixation: Use of newly designed spiral Z-stent endograft

Purpose: To evaluate the feasibility and efficacy of a newly designed stent -graft placed across the renal arteries for exclusion of abdominal aortic a neurysms (AAAs) with short or tortuous proximal necks. Methods: Among a group of AAA patients treated with endovascular grafting, 5 had tortuous proximal necks and 13 had necks <20 mm (mean 13 mm). In thes e 18 cases, a 2-to 3-cm uncovered segment of the stent-graft was placed tra nsrenally using a catheter inserted into the renal artery as a guide for gr aft margin positioning. A newly designed stent-graft was constructed from a custom-made spiral Z-stent covered with a thin-walled Dacron material; the endografts were deployed through 16-F (aortoaortic model) or 18-F sheaths (bifurcated devices). Renal function was assessed by preoperative and posto perative measurement of urea nitrogen and creatinine. Aneurysm exclusion an d renal artery patency were evaluated during follow-up using spiral compute d tomography and angiography. Results: The stent-grafts were correctly placed at the intended site in all 18 patients. Renal function was not affected except transiently in 1 patie nt who developed bilateral renal artery stenoses 24 hours after the procedu re; Palmaz stents were deployed in each renal artery to reestablish satisfa ctory blood flow. Of the 33 renal arteries crossed by the bare stent-graft segment, all were patent over a mean 14-month follow-up (range 7-24), inclu ding the patient with Palmaz stents implanted for postprocedural renal sten osis. Complete aneurysm exclusion was maintained in 15 (83%) of 18 patients ; proximal leaks persisted in 3 patients, including 2 with severely angled proximal necks. Conclusions: Transrenal placement of the uncovered leading edge of custom-m ade spiral Z-stent-based endografts appears feasible and clinically effecti ve in the treatment of AAAs with short or tortuous proximal necks.