168 a renal allograft (Fig. 3). His renal function has remained stable over 18 months of follow-up. DISCUSSION The long-term patient and renal allograft survival rates after renal transplantation have increased. As a result, the number of patients requiring aortoiliac reconstructive surgery after renal allograft is also increasing. Because patients with functioning renal allografts have a high incidence of concur- rent cardiovascular disease, especially hypertension, they may be more susceptible to the development of aneurysmal dis- ease (2, 10). It was recently reported that aortic aneurysms in renal transplant patients have aggressive natural history with high expansion and rupture rates (9, 10). Therefore, one study recommended yearly ultrasounds for the screening of AAA in renal transplant recipients as part of the routine post- transplantation follow-up (10). Given the solitary arterial supply and lack of collateral cir- culation of the renal allografts, these allografts are more sus- ceptible to ischemic injury than are the native kidneys. In general, a renal ischemic time of 60 min is safe; this is sup- ported experimentally (11, 12) and in clinical studies (13, 14). Wahlberg et al. (15) emphasized that the most impor- tant risk factor for allograft ischemic damage is the clamp- ing time of the aorta proximal to the renal artery; they con- cluded that aortic clamping above the renal arteries for up to 50 min appears to be safe. In addition, renal function prior to surgery and hypotension during the operation influence ischemic damage. Although there is no clear evidence that the renal allograft may be seriously damaged by ischemia during aneurysm repair, the risk of ischemic is a concern based on anatomical considerations. Methods have been proposed with the uni- fying purpose of allowing effective aortic replacement while minimizing the risk of allograft loss. These include the use of temporary shunts (1, 2), extracorporeal bypass (3), cold renal perfusion (4, 5), and general hypothermia (6). Howev- er, there are also some reports of successful aneurysm repair without any adjunctive renal protective measures (16, 17). The most obvious method of protecting a renal allograft from an ischemic insult is to maintain perfusion during the ane- urysm repair. The use of temporary shunting techniques, as described above, provides native, oxygenated, pulsatile blood flow to the transplanted kidney. In our case, there was a suf- ficient aortic neck to allow the placement of a purse-string suture and a cannula, so we selected a temporary aortofemoral shunt to avoid renal ischemia. The renal allograft produced urine throughout the AAA repair and there was no transient rise in the serum creatinine level. In addition, we could not identify any deleterious effects from the maneuvers detailed above. Recently, with the development of endovascular techniques, H.-K. Kim, J.-P. Ryuk, H.H. Choi, et al. aortic aneurysms can be repaired without aortic cross-clamp- ing and the associated risk of distal ischemia (7, 8). Endovas- cular repair may be a new renal protective measure, as the allograft ischemia is limited to the brief time that the graft is ballooned into place. Although the possible disadvantages of endovascular repair with a pelvic renal allograft include emboli to the kidney from dislodged atherosclerotic debris during the procedure, as well as the risk of contrast-induced nephropathy, it may be a safe and effective method for the repair of AAAs in selected patients. In summary, our case with a temporary aortofemoral shunt technique illustrates the feasibility of avoiding renal ischemia in patients with a renal allograft during AAA repair. 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