EXPERIMENTAL AND CLINICAL TRANSPLANTATION

En bloc kidney transplants of small pediatric kidneys into adult recipients have been shown to have outcomes similar to transplants from standard adult deceased donors. Here, we report a 27-year-old male patient with successful repair of bilateral ureteral stricture 3 years after en bloc kidney transplant at the Shahid Modarres Hospital (Tehran, Iran). The patient received an en bloc deceased kidney donation from a 9-month-old infant. An end-to-end anastomosis of the aorta to the internal iliac artery and an end-to-side external iliac vein anastomosis to vena cava were performed. At an outpatient visit about 2.5 years later, the patient showed increasing levels of creatinine from 1.1 to 1.8 mg/dL compared with measurements at his 2-month visit. A computed tomography scan performed without any contrast agent at that time confirmed the existence of hydronephrosis in both the medial and lateral kidneys. A nephrostography showed a ureteral stricture. Because endoscopic surgery for ureteral dilatation was not successful, the decision was made to perform ureteral repair by the open surgical technique. The short length of the ureters resulted in the lateral renal pelvis being anastomosed to the bladder by flap (Boari flap). The ureter of the patient's native kidney was transected in the middle portion, and the distal ureter was anastomosed to the medial renal pelvis using the end-to-end method. Here, we showed that, despite limited experiences with pediatric donors, en bloc kidney transplant can be performed under the guidance of experienced surgical techniques and precise postoperative follow-up.

Key words : End-stage renal disease, Infant donor, Renal transplant, Ureteral stricture

Kidney transplant is now considered the best treatment option for patients with end-stage renal disease.¹ Although flourishing surgical transplant techniques and immunosuppression agents are associated with prolonged patient and graft survival, organ availability seems to be an important restriction in developing renal transplant programs. In 1972, en bloc kidney transplant (EBKT) from a pediatric donor to an adult recipient was proposed as a way to surmount the extreme differences between available donor organs and the ever-increasing number of patients.² En bloc kidney transplants of small pediatric kidneys into adult recipients have been shown to lead to outcomes similar to transplants from standard adult deceased donors.^3,4 The transplant of en bloc kidneys from pediatric donors to adult patients is increasingly approved; however, compared with solitary adult grafts, vascular stenosis has been shown to be 3 times more common in EBKTs.⁵ Furthermore, the shorter length and smaller luminal diameter of ureters in kidneys from pediatric donors versus adult kidneys can lead to ureteral complications such as leakage and stenosis, which are more common in EBKT.^6,7 Because these technical complications can be rectified or even dealt with successfully, the implementation of EBKTs is more often considered.8 Here, we report an EBKT from a 9-month-old infant donor to an adult recipient with successful repair of bilateral ureteral stricture 3 years after the transplant.

The patient was a 27-year-old man with end-stage renal disease of unknown cause who had been undergoing hemodialysis before receiving an EBKT from a deceased 9-month-old infant at the Shahid Modarres Hospital (Tehran, Iran) in November 2013. In terms of surgery, an end-to-end anastomosis of aorta to the internal iliac artery and an end-to-side external iliac vein anastomosis to vena cava were performed. The ureters were first anastomosed together using the Wallace method, and then the modified Lich method was used for anastomoses to the bladder. The postoperative course was uneventful; the patient's creatinine level at discharge was 1.8 mg/dL, and his immunosuppression protocol included cyclosporine, mycophenolate mofetil, and prednisolone. The patient attended regular outpatient visits and showed follow-up creatinine level of 1 mg/dL at 3 months postsurgery.

At an outpatient visit about 2.5 years later, the patient demonstrated increased creatinine levels, which rose from 1.1 at 2 months to 1.8 mg/dL at 2.5 years. During this period, the drug regimen had been strictly observed. Ultrasonography showed moderate hydronephrosis in both the medial and lateral grafted kidneys. A computed tomography scan performed without any contrast agent at that time confirmed the existence of hydronephrosis in both the medial and lateral kidneys (Figures 1 and 2).

A Foley catheter was inserted for the patient, but no decreases in creatinine were observed. Therefore, the patient had implantation of bilateral nephrostomy. This resulted in the patient's creatinine level dropping to 1.3 mg/dL.

An examination for BK virus infection showed negative results. Because of the nephrostography, ureteral stricture was observed; subsequent endoscopic surgery for ureteral dilatation was not successful. A decision was made to perform ureteral repair by the open surgical technique. The ureters were observed to be tight and fibrous. During exploration, one of the renal veins was inadvertently transected, which led to an end-to-end anastomosis. Because of the short length of the ureters, the lateral renal pelvis was anastomosed to the bladder by flap (Boari flap). The ureter of the patient's native kidney was transected in the middle portion, and the distal ureter was anastomosed to the medial renal pelvis using the end-to-end method. Computed tomography scans with a contrast agent performed on the patient indicated the elimination of hydronephrosis in both the medial and lateral transplanted kidneys (Figure 4). The patient showed creatinine level of 1.3 mg/dL and had no further complications at follow-up.

Because of the low number of deceased donors for kidney transplant, physicians have been encouraged to develop additional criteria for selecting donors.⁹ En bloc kidney transplant was initially expanded to both enhance the nephron mass, which was transplanted and thus surmounted the challenges of small-caliber vessels in pediatric donors. Despite this allowing an easier procurement and transplant of small pediatric kidneys, challenges remain, although surgical experiences and techniques have improved to significantly influence outcomes.¹⁰ More recently, a plethora of studies have reported a decline in the technical complication rate of EBKTs. Factors associated with improved outcomes have included reduction in cold ischemia time, which is considered as an independent risk factor for arterial thrombosis, induction therapy with antithymocyte globulin, the use of both heparin and antiplatelet agents posttransplant, and technical refinements.^11,12 A variety of technical complications can currently be rectified or even dealt with successfully; thus, utilizing EBKT has been considered as equal to routine deceased-donor transplant in children and adults.^4,8

Despite our encouraging findings, additional efforts should be made into research to further diminish technical complications, particularly graft thrombosis and subseqent ureteral stricture. Vascular thrombosis seems to be the most common vascular complicaton after EBKT from pediatric donors below 2 years old, and the reported graft loss rate is to be 10% to 25%.^13-15 A donor age of 1 year is the recommended threshold to lessen the high graft thrombosis risk and other complications, including ureteral stricture.^15,16 In their study on EBKT, Afanetti and associates found that 3 of 4 patients who received kidneys from donors younger than 1 year experienced graft thrombosis.¹⁷ In another study, Fananapazir and associates scrutinized the clinical and immediate postoperative ultrasonographic factors related to vascular thrombosis of pediatric en bloc kidney grafts. They observed that outcomes of such transplant procedures could definitly be improved.¹⁸

Despite limited experience with small pediatric donors, EBKT can be performed under the guidance of experienced surgical techniques and precise postoperative follow-up.

Volume: 17 Issue: 6 December 2019

FULL TEXT