EXPERIMENTAL AND CLINICAL TRANSPLANTATION

Objectives: Ureteral complications remain a major source of morbidity and occasional mortality in renal transplant. Among all ureteral complications, leaks are the most frequently encountered in the early posttransplant period. The routine use of a double-J ureteric stent remains controversial, with reported increased incidence of urinary tract infection. Here, we retrospectively compared the efficacy of a double J stent in kidney transplant patients to investigate ureteral complication incidence in our center.

Materials and Methods: Our study included 382 kidney transplant patients. At 5 weeks after transplant, the double J stent was removed under sedation. Patients were divided into 2 groups: 125 patients with double J stent placement (group 1) and 257 patients without double J stent placement (group 2).

Results: We observed no significant demographic differences between the 2 groups with regard to patient age (median patient age of 30 y [range, 2-73 y] for group 1; median patient age of 33 y [range, 4-69 y] for group 2), patient sex (30.2% females in group 1, 32.4% females in group 2), and body mass index (median of 25.1 vs 24.9 kg/m² in groups 1 and 2, respectively). Cold and warm ischemia time for donor organ, delayed graft function, and episodes of acute rejection did not differ significantly between the groups. Urinary tract infection was observed in 25/125 (20.4%) and 50/257 patients (19.2%) in groups 1 and 2, respectively. Urinary leak was present in 8/125 group 1 (6.4%) and 6/257 group 2 patients (2.3%).

Conclusions: A double J stent in ureteral anastomosis was not likely to decrease the frequency of leakage but is likely to reduce the gravity of the complication and the need for reoperation. In addition, the use of a double J stent was not associated with increased urinary tract infections in renal transplant recipients.

Key words : Renal transplant, Urinary leaks, Urinary tract infection

Kidney transplantation has long been recognized as the best available therapy for end-stage kidney disease. Although the operative techniques have been refined over time and are now highly standardized, research remains ongoing on the details of the procedure, which may lead to a further reduction of postoperative complications and improved long-term outcomes. Ureteral complications remain a major source of morbidity and occasional mortality in renal transplant despite a reduction in their incidence of at least one-half over the past 30 years. In different transplant centers, the incidence of ureteral complications after renal transplant varies from 2% to 20%. These complications can include urinary leakage from the ureteral anastomosis, fistula, stenosis, and obstruction of the ureteral anastomosis.¹

Among all ureteral complications, leaks are the most frequently encountered complication in the early posttransplantation period.² These complications can cause high morbidity, increased hospitalization time, and subsequent increased costs. Therefore, the use of ureteral stents during kidney transplant as prophylaxis to prevent such complications seems logical.³ Routine ureteric stenting for kidney transplant is widely regarded as beneficial. However, indwelling stents in an immunocompromised patient can lead to a risk of urinary tract infections (UTIs).⁴

Urologic complications can play a significant role in patient outcomes, quality of life, graft loss, cost effectiveness, and hospital stay. Double J ureteral stents have become one of the most basic and valuable tools in urologic practice. Indwelling ureteral stents provide direct drainage of the upper urinary tract to the bladder without the need for external diversion. Double J stents are inserted in patients with ureteral obstruction and for the prevention of complications after open or endoscopic procedures. However, their use is not free of complications and problems.

Many centers use double J stents in every patient, and some centers use this only with selected cases. Routine intraoperative use of double J stents is controversial and still debatable. There are many factors that call for their use, including surgical technique, graft retrieval and ureteric ischemia, patient sex, and source of kidney (deceased or living donor). The insertion of a stent does not eliminate the risk of complications, particularly urinary leak, but may alter the approach to managing them.² Because of need for immunosuppression posttransplant, double J stents in transplant patients can increase the risk of urologic or blood infections. Consequently, opinions continue to be divided between those who routinely conduct stent placement and those who only do so selectively on the basis of clear indications.⁵ A ureteral stent after kidney transplant will usually be removed after 4 to 6 weeks, but it should be noted that the optimal length of time for retaining ureteral stents is controversial and is not yet specified.⁶

To determine whether stent placement increases the risk of UTIs and the incidence of complications with double J stents, we performed a retrospective single-center study to compare the efficacy of double-J stent placement versus no stent placement in kidney transplant patients.

Materials and Methods

Between November 1975 and June 2018, our center performed 2902 kidney transplant procedures. We retrospectively reviewed prospectively collected patient medical records. Our study included 382 kidney transplant recipients (349 from living and 67 from deceased donors). The original total was 416 patients; however, 34 were excluded due to intraoperative complications or cytomegalovirus infection. Of 382 patients, 371 (97%) underwent first transplant, 9 (2%) underwent a second transplant, and 2 (1%) underwent a third transplant. The 382 patients were divided into 2 groups: group 1 (n = 125) included those who had a double J stent and group 2 (n = 257) included those who did not have a double J stent.

The graft was revascularized in a standard way, with the renal vein anastomosed to the side of the external iliac vein. The renal artery was end-to-side to the external iliac artery or end-to-end anastomosed to the internal iliac artery. Both groups of patients underwent corner-saving ureterovesical anastomosis with or without double J stents (with 6/0 polydioxanone). During surgery, a 6F, 12-cm, double pigtail ureteral stent was inserted in group 1 patients (the double J stent group) at the discretion of the surgeon to establish internal drainage from the uretero-pelvic junction to the bladder. The double J stent remained for an average of 42 days (range, 28-75 d). Stents were endoscopically removed under local anesthesia. In both groups, a Foley catheter was left to drain the bladder for 4 days; suction drains were placed for 6 or 8 days. After a policy of selective double J stenting was adopted, the double J stent was used only in cases of difficult ureteric reimplantation, delayed renal function, and/or compromised vascularity.

Immunosuppressive agents included tacrolimus (0.1 mg/kg/day), mycophenolic acid (30 mg/kg/day), and prednisolone (1 mg/kg/day). Antibiotic prophylaxis included a single intravenous dose of cefazolin (1 g) at anesthetic induction and a daily dose of cotrimoxazole (480 mg) for 3 months. Induction therapy with anti-CD25 monoclonal antibodies (basiliximab 20 mg) was given to 22 patients in group 1 and to 21 patients in group 2 on day 0 and day 4. Baseline serum creatinine levels were recorded preoperatively and daily during hospitalization posttransplant. Color Doppler sonography was performed daily for the first postoperative week and as needed afterward to assess organ perfusion and vascular resistance as well as for diagnosis of postoperative complications, including hydroureter and/or hydronephrosis, lymphocele, urine leak, and hematoma.

Endpoints of this study were postoperative complications (including UTIs, ureteric stenosis, anastomotic leakage, and macrohematuria). In addition, the length of hospital stay was evaluated and compared between the 2 groups.

The diagnosis of UTI was made on the basis of compatible symptoms supported by urinalysis and/or microbiologic culture. These finding were in conjunction with at least one of the following symptoms in patients with no other recognized cause: fever (> 38°C), urgency, frequency, dysuria, and suprapubic tenderness.

Ureteric obstruction was defined as a rise in serum creatinine levels by more than 20%, ultrasonographic evidence of hydronephrosis, and verification of the stenotic anastomosis by retrograde pyelography. Anastomotic leakage was defined as any amount of contrast agent outside the transplant ureter or bladder detected by retrograde pyelography, performed during the first postoperative week.

Statistical analyses were performed with SPSS software (SPSS Inc., Chicago IL, USA). Group means or medians were compared using unpaired t test; contingency tables were analyzed with the Fisher exact test.

In our patients, the most common causes of established renal failure were glomerulonephritis (14.7%), cystic kidney disease (14%), immunoglobulin A nephropathy (13.3%), and diabetic nephropathy (6.7%). No significant demographic differences were observed between the 2 groups regarding patient age (median patient age of 30 y for group 1, and median age of 33 y for group 2), distribution of male versus female patients (30.2% vs 32.4% females in group 1 vs group 2), and body mass index (median 25.1 vs 24.9 kg/m² in group 1 and group 2). Duration of cold and warm ischemia time in the donor organ, delayed graft function, and episodes of acute rejection did not significantly differ between the groups (Table 1). Indications for stenting in the 125 patients with placement of double J stents during transplant are shown in Table 2. Thirteen patients were stented at subsequent reimplantation of the transplant ureter (stenosis/stricture in 10 patients and urine leak in 3 patients).

Postoperative complications are shown in Table 3. Urinary tract infections were observed in 25/125 patients in group 1 (20.4%) and 50/257 patients in group 2 (19.2%). Escherichia coli was the most frequent causative organism, followed by Klebsiella and Enterococcus species. Three patients developed Candida species infection. The mean serum creatinine level at the end of year 1 was 1.47 mg/dL in group 1 patients and 1.36 mg/dL in group 2 patients (Table 4). Patients in both groups were treated with appropriate antibiotics after urine culture analyses. Urinary leak was present in 8/125 patients in group 1 (6.4%) and 6/257 patients in group 2 (2.3%). On average, patients presented with a urinary leak on postoperative day 6 (range, day 5-11). Leaks were treated with a Foley catheter reinserted for 7 days with no surgical or radiologic interventions. As shown by Pearson correlation test, incidences of urinary tract infection and anastomosis were not significantly different between groups.

The overall mean length of hospital stay was comparable in the 2 groups (8 days in group 1 and 7 days in group 2; P = .533). There were fewer occurrences of secondary macrohematuria in group 1 (13/125 patients) than in group 2 (24/257 patients; P = .568).

Prophylactic ureteric stenting in renal transplant recipients remains a matter of controversy. Although ureteric stents can prevent major surgical complications like ureteric leak and obstruction, they can also be associated with complications like UTI, hematuria, stent migration, stent encrustation, and forgotten stents.⁷

There are wide variations in the frequency of UTIs in stented versus nonstented renal transplant recipients. Ranganathan and associates found a significantly higher incidence of UTIs in stented than in nonstented patients (71% vs 39%).⁸ Osman and associates⁹ reported that 36% of stented renal transplant patients had UTIs compared with 18% in the nonstented group. However, in a retrospective, comparative, single-center study involving 310 renal transplant patients, Mathe and colleagues found similar rates of UTI in stented (43.3%) versus nonstented patients (40.1%).¹⁰ Derouich and associates reported a frequency of occurrence of postoperative UTIs of 47.2% in stented versus 48.7% in nonstented renal transplant recipients.¹¹ In our study, we found no significant difference in the frequency of UTIs in stented versus nonstented renal transplant recipients (20.4% vs 19.2%).

Early removal of the double J stent may have some role in the prevention of stent-related complications.¹² Tavakoli and associates advocated removal of the double J stent within 28 days and reported a significantly high rate of UTI after 30 days of stent insertion in renal transplant recipients.¹³ In our study, there was no significant difference in graft function in the 2 groups after 1 year of follow-up (serum creatinine level of 1.47 vs 1.36 mg/dL in stented versus nonstented patients, respectively). This finding is similar to previous data.⁹ The slightly elevated creatinine level in the stented group is probably a reflection of our policy of selective double J stent placement, in which patients with delayed graft function, poor ureteric blood supply, or difficult anastomosis are selected for stent placement. In addition, Escherichia coli was the most common organism causing UTI in both the stented and nonstented groups.

The optimal duration of stent placement in renal transplant is not known. In this study, the average duration for stent placement over our study period was 42 days (range, 28-75 d). However, stent duration did not significantly correlate with risk of infection. We suggest that the ureter stent should be withdrawn as soon as possible. This approach is similar to that reported by Verma and associates in a case control study in which stenting for 4 weeks avoided the complications associated with prolonged stenting without compromising the benefits.¹⁴Tavakoli and associates showed that the rate of UTIs was increased, especially if stents were left in for more than 30 days, although they advocated stent removal after 4 weeks.¹³ The matter of how long to leave a stent in situ is an important one and possibly requires further investigation with a randomized controlled trial. Perhaps another way to reduce the infection complications of stents is through technological development of better materials to reduce or prevent bacterial adherence to the stents.

The finding that urine leak rate was not affected by the placement of ureteric stents in this series is similar to the report by Dharnidharka and associates, who showed that stents offered no benefit in preventing ureteric stenosis or leaks nor in improving graft survival.¹⁵ Although lower leak rates have been shown in patients with stent placement,^13,16 Osman and associates⁹ found a small increase in leakage in their stented group (4% vs 0%) and a significant increase in UTIs. Factors like stripping of the ureter, ureteric injury, multiple renal arteries, damage to lower polar artery, operative techniques, cold ischemia time, and donor vascular disease may be more important risk factors of urine leak.

Typical postoperative complications after kidney transplant include obstruction, stenosis or kinking of the transplant ureter, insufficiency of the uretero-neovesicular anastomosis, and UTIs and postoperative macrohematuria. These complications can lead to obstruction of urinary drainage and complications due to the heightened pressure on the transplanted kidney as well as the anastomosis.⁴ Improved mortality rates and graft survival and decreased morbidity have allowed renal transplant to become the treatment of choice for patients with end-stage renal disease. Urinary leakage, the most common complication during the early posttransplant period, has been reported to occur at a rate of 0% to 8.9%.¹⁷ The most frequent cause of urinary leakage is ureteral necrosis due to ischemia.¹⁶

In conclusion, carefully used surgical techniques to avoid urologic complications during organ recovery and implantation have decreased the incidence of urologic complications, especially leakage. In our series, the use of a double J stent in ureteral anastomosis did not decrease the frequency of leakage and UTIs; however, stent placement can reduce the gravity of the complication and the need for reoperation. Notwithstanding the retrospective nature of this study, stents did not increase the risks of urologic infections. Whether stents are used routinely or selectively, there is need to remove them early (< 4 wk) to reduce the risk of infection.

Volume: 17 Issue: 1 January 2019 - Supplement - 1

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