EXPERIMENTAL AND CLINICAL TRANSPLANTATION

Objectives: Renal transplant is the most appropriate treatment for both adult and pediatric patients with end-stage renal failure. Here, we analyzed surgical complications after pediatric renal transplant at our center.

Materials and Methods: We retrospectively analyzed data from patient files and hospital charts of pediatric patients who had renal transplant at our center (Gazi University, Ankara, Turkey). Our immunosuppression protocol, a calcineurin inhibitor-based triple regimen, was applied to all recipients (steroids, mycophenolic acid). For neo-ureterocystostomy anastomosis, we used the corner-saving, open-loop continuous suture technique with double J stent for all patients, except when faced with an unfavorable situation. Catheters were removed within 4 weeks after transplant.

Results: Among 40 pediatric renal transplant procedures performed at our center since 2006, we had 6 documented surgical complications (15%), with 3 being early and 3 being late complications. In the early transplant period, there were 2 surgical and 1 urologic complications. Eight patients (20%) lost their kidney grafts over the 10-year follow-up. The main reasons for graft loss were chronic allograft nephropathy in 4 patients (10%), BK virus nephropathy in 3 patients (7.5%), and hyperacute rejection in 1 patient (2.5%). Two patients died; however, no patient deaths or graft losses were from surgical complications. Overall graft and patient survival rates were 97% and 100% at 1 year, 94% and 98% at 5 years, and 68% and 95% at 10 years.

Conclusions: Renal transplant in pediatric patients is a safe procedure in our department, based on patient and graft survivals, with a low rate of graft loss from surgical problems. As a result, our center is showing success with pediatric renal transplant procedures in accordance with the developed centers in the world.

Key words : Pediatric renal transplantation, Outcome

Renal transplant is the most appropriate treatment for both adult and pediatric patients with end-stage renal failure. The obstacles shown in pediatric patients with renal failure include hospitalizations, psychosocial effects of dialysis, immature immune system, and elusive donor matching according to body size.^1,2 Renal transplant procedures in pediatric patients are performed later than in adult patients, with desired success achieved soon after because of difficulties previously mentioned.^1,2 Despite the advances in surgical techniques and immunosuppressive regimens, surgical complications remain important clinical problems, which may increase the morbidity rates, duration of hospital stay, and costs. Some of these complications can be life threatening, and early recognition of these complications and treatment can save both the patient and the graft. Pediatric patients can catch up with normal growth and development through an optimum and controlled immunosuppressive treatment plan after transplant.^1-3

Materials and Methods

At our center, standard surgical techniques are used.1 Briefly, we use a retroperitoneal approach for recipients with body weights greater than 25 kg. An intra-abdominal placement of graft is preferred for infants who are less than 20 kg. For infants having body weights between 20 and 25 kg, the surgical technique and graft placement should be decided according to physical body dimensions. For renal artery and vein anastomoses, we use monofilament nonabsorbable sutures of 7-0 for arteries and 6-0 for veins. For ureteral anastomoses, we use the corner-saving, open-loop continuous suture technique with 5-0 Polydioxanone sutures (PDS) of Haberal and associates.⁴ Furthermore, our experience has shown that use of a double J stent increases the anastomosis safety in neo-ureterocystostomy anastomosis. Unless faced with unfavorable situations, we remove this catheter 4 weeks after transplant.² All recipients used trimethoprim/sulfamethoxazole for prevention of pneumocystis pneumonia for 3 months after transplant.

Our immunosuppression protocol has been published previously.^1,5 Briefly, all recipients received a calcineurin inhibitor-based triple regimen (steroids, mycophenolic acid). In high-risk patients, such as those with high panel reactive antibody levels, those who received grafts from deceased donors, or those who had multiple transplants, interleukin 2 receptor antagonists were used as an induction therapy. The starting dose of prednisolone was 10 to 15 mg/kg, with dose tapered to a maintenance dose of 5 mg/day in 3 months until 12 months. Prednisolone is given every other day at 5 mg/day for 1 year after transplant. For those with delayed graft function, antithymocyte globulin as polyclonal antibody was preferred instead of calcineurin inhibitors until graft functions had returned to an acceptable level (normovolemic urine output and 50% decrease of serum creatinine levels in 24 h or creatinine level < 3 mg/dL). Although the initial treatment for acute rejection cases is pulse steroid, polyclonal (generally antithymocyte globulin) or monoclonal antibodies (interleukin 2 receptor blockers) can be used for steroid-resistant rejection.

Since 2006, 40 pediatric kidney transplant procedures have been performed at the Transplantation Center, Gazi University (Ankara, Turkey). Patients included 18 female and 22 male recipients. The mean age was 13.4 ± 3 years (range, 4.5-17 y). Kidney grafts were obtained from 14 deceased donors (35%) and 26 living related donors (75%). All operations were performed by the same transplant team. The data were retrospectively analyzed from patient files and hospital charts.

Among 40 pediatric renal transplant procedures, 6 surgical complications (15%) were seen. Three complications were judged as early and 3 were judged as late complications. In the early transplant period, there were 2 surgical complications and 1 urologic complication. Two lymphocele cases (5%) were shown to be surgical complications. All lymphocele cases were diagnosed by ultrasonography and confirmed by needle aspiration of the lymphocele content and estimation of the creatinine concentration of the aspirate. One patient with lymphocele needed drain placement, which was performed with use of interventional radiology. No fluid collection occurred again, and no further intervention was needed. The other patient with lymphocele had spontaneous resolution. Urinary leakage was detected in one patient on day 3. This patient was the only pediatric patient with an early urologic complication, which was treated successfully with interventional radiology.

Late complications included 1 case of renal artery stenosis and 2 cases of distal ureter stenosis. The renal artery stenosis was treated with balloon angioplasty and polytetrafluoroethylene grafting. For the distal ureter stenosis, both patients required balloon dilatation but not stenting. All patients recovered well with excellent graft function.

Eight patients (20%) had loss of kidney grafts during the 10-year follow-up. The primary reasons included chronic allograft nephropathy in 4 patients (10%), BK virus nephropathy in 3 patients (7.5%), and hyperacute rejection in 1 patient (2.5%). In our study group, 2 patients died. Twenty-eight patients (70%) showed normal graft function over the median 77-month follow-up. No other surgical complications, such as wound-related problems, infections, incisional hernia formation, or suture infection were shown. None of the patient deaths or graft losses was due to a surgical complication. Overall graft and patient survival rates in our patient group were 97% and 100% at 1 year, 94% and 98% at 5 years, and 68% and 95% at 10 years.

Renal transplant continues to be the best option for end-stage renal disease replacement therapy in pediatric patients. The rates of surgical complications with this procedure are presently lower than previously because of improvements in immunosuppressive regimens and refinements in operative techniques. As surgical experiences have increased in many centers, easier and safer techniques have been adopted to produce fewer complications. Nevertheless, renal graft survival has been related not only to protocols of immunosuppression and of donor and patient selection but also to surgical complications and their treatment. These complications rarely lead to graft loss, with the exception of vascular problems or patient death.

Renal artery stenosis remains a potentially serious complication after transplant. The reported incidence ranges from 1% to 23% and is associated with medically refractory hypertension and progressive allograft dysfunction; it can result from an inadequate suture technique, renal artery trauma, kinking of the artery, vascular type rejection, and atherosclerosis of the donor or the recipient arteries.^7-10 It should be suspected when there is an onset of hypertension or significant increase in blood pressure over previous levels, often accompanied by proteinuria and/or an increase in plasma creatinine levels. The prevalence of renal artery stenosis in transplant has increased with the introduction of new noninvasive diagnostic methods.^6-10 Care consists of surgical revision or percutaneous transluminal angiography with balloon dilatation or placement of an endovascular stent. None of the patients required surgical revision. Only 1 patient with renal artery stenosis due to refractor hypertension needed balloon dilatation and stent placement by interventional radiology without any further treatment.^10,11

Urologic complications can be a real threat to graft and even patient survival. In the literature, urinary leakage and obstruction have an especially considerable mortality rate. In our study, no patient died because of urologic complications, and we showed considerably good results (urinary leak rate was 2.5%, stenosis rate was 5%) compared with the literature (2.5%-25%).^12-15 Decreased blood supply to the donor ureter and faulty surgical techniques are the main causes of urologic complications; however, other problems, such as immunosuppressive drugs and rejections, can cause late obstruction. Although low-dose steroid protocols and meticulous operative techniques tend to reduce incidence or urologic complication,¹⁰ poor ureteral vascularization owing to increased use of expanded criteria donors, especially older individuals, tend to increase this rate. As observed in our department, the technique of ureteral anastomosis does not seem to influence the incidence of complications. We mainly have adapted the extravesical Lich-Gregoir technique to the corner-saving technique with an antireflux mechanism. The incidence of urologic complications in our series was comparable with other pediatric transplant experiences.

Lymphocele, a surgical complication of renal transplant, shows an incidence of 0% to 20%.¹⁶ Most lymphoceles are asymptomatic; however, when symptomatic, the presentation includes bulging abdomen, liquid leakage from the wound, and obstructive acute renal failure. Lymphocele is rarely responsible for sepsis or deep vein thrombosis. In our study group, we did not see any major complication related to lymphocele. Only 1 patient with lymphocele needed drain placement by interventional radiology; collection did not reoccur, and the patient did not need any further intervention. The other 2 lymphoceles resolved spontaneously.

According to our results, 10-year survival of kidney graft was 68%. Exiguity of graft loss due to immunologic reasons and also infection rates less than the mean rate in the literature showed the efficiency of our immunosuppressive treatment and postoperative follow-up strategy. These results support that the experiences of our surgical and anesthesia team and conditions of intensive care and hospitalization are proportional with long-term success of pediatric transplant, despite several difficulties, including small body sizes, small vascular diameter, and more complicated surgical manipulations in children.

Renal transplant in pediatric patients is a safe procedure in our department, based on our patient and graft survival rates, with a low rate of graft loss owing to surgical problems. As a result, our center is showing success with pediatric renal transplant procedures in accordance with the developed centers in the world.

Volume: 17 Issue: 3 June 2019

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