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Custom Stent Grafts for Abdominal Aortic Aneurysm

Abominal aortic aneurysms occur when a weakened portion of the wall of the abdominal aorta bulges due to circulatory pressure, threatening to rupture as it grows. Rupture must be avoided because it is associated with mortality rates of 80% to 90%. To prevent rupture, a graft is placed within the aneurysm to seal it and appropriately direct blood flow, thereby protecting against further growth or rupture of the aneurysm.

The graft can be placed either in open surgery or via an endo- vascular approach. Open surgery is the traditional option in health- ier patients but requires a large abdominal incision and clamping of the aorta while the graft is placed. Endovascular aneurysm repair offers a better treatment option for patients too sick for surgery, for example those with preexisting heart problems that would make the cardiovascular stress of clamping the artery too dangerous. With the endovascular approach, a stent graft mounted on a catheter is inserted into the femoral artery and threaded to the aneurysm site, where the stent graft is precisely positioned and deployed to seal the aneurysm.

Traditional endovascular grafts could be placed only if the aneurysm were below the renal arteries because placing it any higher would cut off the blood supply to the kidneys. This left many patients with complex abdominal aortic aneurysms few or no treat- ment options. To help more patients, physicians began “customizing” the stent grafts, modifying them to accommodate the patient’s anatomy and the aneurysm’s morphology.

Although vascular surgeons and endovascular specialists at the MUSC Heart and Vascular Center (HVC) are adept at customizing stent grafts to make endovascular repair available to more patients with complex abdominal aneurysms, they would welcome the availability of customized fenestrated and branched iliac devices that are approved by the US Food and Drug Administration (FDA).  According to Nitin Garg, M.D., Assistant Professor of Surgery, “Fenestrated and branched endografts would change how aneurysms are treated and would allow treatment in patients who would otherwise be considered too high risk for open surgery.”

The fenestrated device (Cook Medical, Bloomington, IN) can be used in patients with an aneurysm at the level of or higher than the renal arteries because, as its name implies, it has holes or windows in the stent graft that allow blood supply to the kidneys. A branched iliac attachment is available for patients with aneurysms that extend into both arms of the branched iliac artery (Figure). This branched device allows blood flow to be maintained to one or both of the iliac branches, preventing the hip pain, sexual dysfunction,  and rare skin loss that can occur if both branches are sacrificed, as is sometimes necessary with traditional stent grafts. Careful measurements of the patient’s anatomy and aneurysm are taken for stent grafts and sent to the company in Australia, where custom grafts are manufactured for each patient.

Approval by the FDA of these innovative stent grafts awaits the results of clinical trials that are in their final stages. Because the HVC at MUSC is the only site in South Carolina chosen to use fenestrated grafts and to participate in the final clinical trials for branched stent grafts, its team of endovascular specialists, led by Dr. Garg and including Drs. Thomas E. Brothers, Bruce M. Elliott, Jacob G. Robison, and Claudio Schonholz, is currently offering these innovative stent grafts to selected patients with complex abdominal aneurysm.

This article originally appeared in the January 2013 issue of Progressnotes.