TRANSPLANT KIDNEY PROTECTION DURING AORTIC ANEURYSM SURGERY

TRANSPLANT KIDNEY PROTECTION DURING AORTIC ANEURYSM SURGERY

0022-5347/99/1613-0891$03.00/0 THE ,Jl>L7WAL OF URULOCV Copyright 0 1999 by AMERICAN UROLOCICAL kSSOCIATlON, INC Vol. 161, 891-892, March 1999 Printe...

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0022-5347/99/1613-0891$03.00/0 THE ,Jl>L7WAL OF URULOCV Copyright 0 1999 by AMERICAN UROLOCICAL kSSOCIATlON, INC

Vol. 161, 891-892, March 1999 Printed in U.S.A.

Urologists at Work TRANSPLANT KIDNEY PROTECTION DURING AORTIC ANEURYSM SURGERY K. NINAN CHACKO,

SARAH NINAN, C. K. JACOB

AND

ROY KORULA

From the Departments of Urology, Anaesthesia, Nephrology and Cardiothoracic Surgery, Christian Medical College and Hospital, Vellore, Tamil Nadu, India

ABSTRACT

Purpose: Renal allografts are sensitive to ischemic insult. During aortic cross clamping prevention of ischemic damage to a kidney below a n aneurysm is vital. Many maneuvers have been reported. We describe a simple technique of protecting the transplant kidney from ischemic damage during aortic surgery. Materials and Methods: During vascular cross clamping a sterile ice slush was placed around the kidney for surface cooling, obviating the need for some of the complicated procedures previously reported. Results: After removal of the ice slush and clamps, urine production resumed and creatinine levels remained unchanged. Conclusions: External cooling with ice slush provides adequate renal protection during aortic cross clamping and requires no special expertise or equipment. KEYWORDS:transplantation, kidney, aortic aneurysm, ischemia

The number of renal transplant recipients who present with aortic problems is likely to increase due to accelerated atherosclerosis, the selection of older and at risk patients, and longer survival. Abdominal aortic aneurysms and aortoiliac disease requiring surgery after transplantation necessitate allograft protection from ischemic damage during aortic cross clamping. The transplanted kidney is thought to be at increased risk of ischemic damage.' Protection techniques have included temporary vascular bypass using only the backflow, perfusion with a pump-oxygenator and direct cold perfusion. CASE HISTORY

A 51-year-old man, who was diabetic, and on maintenance immunosuppression with azathioprine and prednisolone, presented with a midline abdominal mass 4 years after renal transplantation from a living related donor. Serum creatinine was 1.4 mg./dl. (normal 0.8 to 1.6). Ultrasound revealed an abdominal aortic aneurysm and computerized tomography confirmed a leaking infrarenal saccular aortic aneurysm (see figure). TECHNIQUE

The aorta, aneurysm, right common iliac vessels and external iliac vessels were exposed through a midline transperitoneal incision and taped. The cecum and peritoneum were peeled off of the superior surface of the allograft. The lateral and posterior surfaces were dissected and freed sufficiently to place a rubber dam around the graft. The patient was given 1 mg./kg. body weight heparin intravenously, injection of 100 ml. 20% mannitol and 3 pg.lkg. per minute dopamine infusion. The right common iliac vessels above and external iliac vessels below the graft were cross clamped. Accepted for publication October 2, 1998.

Computerized tomography shows aneurysm and graft

Sterile ice slush, made by freezing isotonic saline (0.9% sodium chloride), was packed around the allograft. The aorta was cross clamped and the aneurysm was exposed. Clots were evacuated and the saccular aneurysm was repaired using pledget sutures. The ice slush and clamps were removed after 30 minutes of ischemia. Urine production was prompt and maintained postoperatively with no change in serum creatinine. DISCUSSION

There are more than 20 reports of aortic aneurysms in patients with renal transplants who have undergone subsequent operations, and protecting the kidney from ischemic 89 1

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TRANSPLANT KIDNEY PROTECTION DURING AORTIC ANEURYSM SURGERY

damage during aortic clamping is the major reason. Lacombe reported 4 cases of aneurysm repair without specific renal protection.' In 1patient postoperative acute tubular necrosis developed and took 2 weeks to resolve. Lacombe depended on the backflow to perfuse the allografts with ischemia times of 29 to 50 minutes. Depending only on the backtlow with warm ischemia times more than 30 minutes appears to have an unacceptable degree of risk for the transplanted kidney as one may not always be able to reestablish flow within that time. Campbell et a1 used a pump-oxygenator to maintain hypothermic perfusion by cannulating the femoral vessels.2 Urine production occurred only when the perfused flow rates exceeded 600 ml. per minute. It is unlikely that this flow can be achieved with backflow alone. Nghiem and Lee performed in situ renal perfusion through the right common iliac artery using cold Ringer's lactate ( 4 0 3 Sterioff and Parks: and O'Mara et a15 used a temporary vascular bypass from the aorta to the common iliac or femoral artery. Gibbons et a1 used a temporary axillofemoral graft6 It is also theoretically possible to use inosine7 or cold perfusion of the graft artery after dissecting out the vessels.' A potentially risky hilar dissection is required for direct cold perfusion of the transplant vessel but would ensure longer safe cold ischemia time. All of these methods require special equipment and expertise. Sterile ice slush made from physiological saline is usually freely available in any operating room. Mobilization need not occur anywhere near the critical hilum of the graft, making the procedure less difficult to perform. Peeling off the peritoneum is all that is required to expose the anteromedial surface. External cooling with ice slush has been used extensively in renal stone surgery with safe ischemia possible for as long as 90 minutes.8 It is difficult to cool the core of the kidney below 15C with ice slush. Perfusion with cold fluids usually achieves lower temperatures. It is now believed that mild hypothermia is superior to cold perfusion at 4C as achieved in machine preser~ation.~. lo This method may not be applicable for complicated abdominal aortic aneurysms requiring prosthetic grafts and ischemia times longer than 90 minutes.

CONCLUSIONS

Aortic surgery requiring temporary ischemia to the transplant kidney can be safely performed without complicated or risky procedures. External cooling with ice slush can provide adequate renal protection against acute tubular necrosis and requires no special expertise. This procedure can be performed even at a small hospital during abdominal aortic aneurysm repair in a patient with a renal transplant, autotransplant or pelvic kidney. REFERENCES

1. Lacombe, M.: Abdominal aortic aneurysmectomy in renal transplant patients. Ann. Surg., 203 62, 1986. 2. Campbell, D. A,, Jr., Lorber, M. I., Arneson, W. A,, Kirsh, M. M., Turcolle, J. G. and Stanley, J. C.: Renal transplant protection during abdominal aortic aneurysmectomy with a pumpoxygenator. Surgery, 90:559, 1981. 3. Nghiem, D. D. and Lee, H. M.: In situ hypothermic preservation of a renal allograR during resection of abdominal aortic aneurysm. h e r . J. Surg., 4 8 237, 1982. 4. Sterioff, S. and Parks, L.: Temporary vascular bypass for perfusion of a renal transplant during abdominal aneurysmectomy. Surgery, 8 2 558, 1977. 5. O'Mara, C. S., Flinn, W. R., Bergan, J . J . and Yao, J. S. T.: Use of a temporary shunt for renal transplant protection during aortic aneurysm repair. Surgery, 94: 512, 1983. 6. Gibbons, G. W., Madras, P. N., Wheelock, F. C., Sahyoun, A. L. and Monaco, A. P.: Aortoiliac reconstruction following renal transplantation. Surgery, 91: 435, 1982. 7. Fernando, A. R., Armstrong, D. M. G., Griffits, J. R., Hendry, W. F., ODonoghue, E. P. N., Perret, D. and Ward, J. P.: Enhanced preservation of the ischaemic kidney with inosine. Lancet, 1: 555, 1976. 8. Metzner, J . P. and Boyce, W. H.: Simplified renal hypothermia: an adjunct to conservative renal surgery. Brit. J . Urol., 44:76, 1972. 9. Ward, J. P.: Determination of the optimum temperature for regional renal hypothermia during temporary renal ischaemia. Brit. J. Urol., 47: 17, 1975. 10. Kasicke, B. L., ODonnell, M. P., Berens, K. and Keane, W. F.: Mild hypothermia gives better functional preservation than cold or normothermic perfusion of rat kidneys. Transplant. Proc., 2 2 403, 1990.