EXPERIMENTAL AND CLINICAL TRANSPLANTATION

Objectives: Throughout the world, 45 000 kidney transplants are performed per year. Graft and overall survival vary according to the type of donor (living or deceased donor). Anastomosis of a short renal vein with iliac vein or common external iliac vein has been associated with technical problems such as angulation of the vein or tension on the anastomosis, which could limit visualization and control of bleeding from the graft. The main objective of our study was to analyze patients undergoing deceased-donor kidney transplant and compare results in patients who had extension of the right renal vein with a patch of vena cava from the same donor versus patients who received the left kidney.Materials and Methods: A prospective cohort study was performed from December 31, 2007 to December 31, 2009. We compared 2 patients groups. We used statistical software (R, Version 2.5.1). The analyzing team was blinded to the surgical technique, and informed consent was obtained from all patients.

Results: There was no statistically significant dif-ference in surgical time (P > .85) or ultrasonographic parameters between groups, but it was possible to perform an easier vein anastomosis with the vena cava graft in right kidney transplant.

Conclusions: We recommend considering our procedure with the vena cava graft in right kidney as an alternative option to decrease warm ischemia time, perform an easier vein anastomosis with the vena cava extension, and make the procedure comfortable for the surgeon.

Key words : Anastomosis, End-stage renal disease, Kidney, Venous turbulence

Kidney transplant is required when chronic renal failure reaches a terminal stage.¹ The most common causes of renal failure are diabetes mellitus, systemic arterial hypertension, and glomerulonephritis.^1,2 The estimated number of patients per year requiring substitutive renal therapy due to terminal chronic renal failure is 335 per million in the United States.² This condition is an important public health problem because of its frequency.

Throughout the world, 45 000 kidney transplants are performed per year. The 1- and 5-year overall survival of a kidney transplant is 95% and 85%, and the transplanted organ function is 91% and 68%.^1,2 In Europe and the United States, 80% kidney transplants come from deceased donors and 20% from living donors. This proportion is inverted in Latin American countries because of limited availability of deceased-donor grafts and logistics.^1,2

Graft and overall patient survival vary according to the type of donor. It is higher for transplants from living-related donors or donors with higher histologic compatibility; these have a lower rate of complications than transplants from deceased donors.²

A major complication is graft rejection. Acute rejection occurs within the first 2 to 4 weeks in 30% patients.^1,3 The surgical complications are hemorrhage (6%), wound infection (up to 5%), and technical problems that may cause venous thrombosis (0.5%) or arterial thrombosis (0.6%), which usually may cause loss of the graft.^1-3

Anastomosis of the right renal vein can be technically difficult, especially in obese patients and patients who have deep localization of iliac vessels. The right renal vein often is short, causing technical difficulty to perform the anastomosis during the transplant procedure.^4,5 Anastomosis of a short renal vein with the iliac vein or common external iliac vein has been associated with technical problems such as vein angulation and tension on the anastomosis, and this condition limits the visualization and control of bleeding from the graft. Several procedures for extension of the right renal vein with cava grafts have been reported, but increased turbulence in the renal vein could be produced, which could eventually cause thromboses.^4,5

The main objective of our study was to compare patients who received kidneys with a patch of vena cava versus those who received left kidneys. We used Doppler ultrasonography to assess the arterial and venous flow speed, resistance index, arterial pulsatility index, and presence of venous turbulence, and we evaluated surgical time.

Materials and Methods

A prospective cohort study was performed from December 31, 2007 to December 31, 2009 at the Hospital Central “Dr. Ignacio Morones Prieto” in San Luis Potosi, S.L.P., Mexico. We compared patients undergoing transplant with a right kidney implanted with patch of vena cava versus patients who had left kidney transplant from deceased donors. We included patients of any age and both sexes with the diagnosis of chronic renal failure requiring a kidney transplant.

No patients were excluded. Before starting the study, a list of random sequence numbers was generated with statistical software (R for Windows, Version 2.5.1, Institute for Statistics and Mathematics, Wirtschaftsuniversität Wien, Vienna, Austria).⁶ The statistical team was blinded from the surgical technique. Informed consent was obtained from all patients.

The following variables were studied: age (y), sex, cause and duration of renal failure (y), cold ischemia time (h), duration of surgery (h), creatinine on postoperative day 3 (mg/dL), creatinine at 1 and 3 months after transplant (mg/dL), urea on post-operative day 3 (mg/dL), urea at 1 and 3 months after transplant (mg/dL), complications, and mortality. We used Doppler ultrasonography to evaluate the arterial and venous flow velocities, resistance index, arterial pulsatility index, and presence of venous turbulence in both kidneys.

Surgical technique
Using a Gibson open incision sufficiently wide in any of the iliac graves, an extraperitoneal dissection is performed to expose the perivascular lymph vessels. The graft incorporation is performed with termino-terminal vascular anastomosis.^7-9 The kidney with the extension of the renal vein, is sutured transverse to the inferior cava vein. The renal vein is lengthened with contralateral ostium technique. Suprarenal and infrarenal vena cava ostia are closed with continuous polypropylene sutures (Prolene 6-0, Ethicon, Somerville, NJ, USA) (Figure 1).

An anastomosis was performed with the ostium of the left renal vein.^10-13 This provided continuity of the urinary tract through a ureterocystic anastomosis with an antireflux running polydioxanone suture (5-0).^14-18

Statistical analyses
The analysis was performed using statistical software (R for Windows). Normality was tested with Shapiro-Wilk test and graphically. Comparisons were made with t test for continuous variables and chi-square test for categorical data. Significance was defined as P ≤ .05.

The deceased donors were 11 men and 8 women (mean age, 25 ± 10.7 y). The transplanted patients were 20 men and 17 women (mean age, 37.9 ± 14.1 y). The most frequent causes of renal failure were idiopathic (37.8%), diabetic nephropathy (27.03%), primary glo-merulonephritis (16.22%), renal hyperplasia (8.11%), and other causes. Most (64%) patients at transplant had medical therapy for mean 3.8 ± 2.8 years, and mean cold ischemia time was 7.8 ± 4.3 hours. The right kidney was implanted in 19 patients and the left kidney was implanted in 18 patients. The results of the study population were tabulated (Table 1).

We observed in 19 patients who received a right kidney transplant the following complications: 1 patient had acute rejection and required nephrectomy, 2 patients had a surgical wound infection, and 1 patient developed a hematoma and had surgical intervention for drainage and control of bleeding. No mortality was observed in this group.

In the 18 patients who received a left kidney, 2 patients presented with acute rejection (1 patient responded to medical treatment and 1 patient required nephrectomy). There was 1 patient who died after 2 months unrelated to the surgical procedure; the cause of death was urosepsis due to Pseudomonas aeruginosa.

We did not observe any difference in arterial and venous flow speed, resistance index, arterial pulsatility index, or presence of venous turbulence between groups (Table 2).

Although a difference in surgical time between the groups was not observed, it was possible to decrease slightly the warm ischemia time by performing an easier vein anastomosis with the vena cava extension. Similarly, tension on the vessels that may cause changes in arterial and venous flow speed, resistance index, arterial pulsatility index, and presence of venous turbulence, measured with Doppler ultrasonography, was not observed during the venous anastomosis; these ultrasonography measures are well known as poor prognostic factors for renal graft dysfunction with long-term progression of chronic renal failure.^19,20 In the case of the right renal vein extension, the mobilization of the graft was easier, and bleeding control made this procedure comfortable for the surgeon.²¹

Although the anastomosis of a short renal vein with iliac vein or common external iliac vein is performed commonly with a high rate of initial technical success,²¹ a low but significant risk of vascular complications can develop and threaten the transplanted kidney. Complications include transplant renal artery stenosis, extraparenchymal and intrapa-renchymal pseudoaneurysm and arteriovenous fistula formation, and stenosis of native iliac arteries due to aortoiliac occlusive disease.²¹ In our study, these complications in both surgical procedures were not observed; therefore, the extension of right renal vein in renal transplant from deceased donors probably is a safe procedure, in comparison with the anas-tomosis of a short renal vein with iliac vein or common external iliac vein. Only 1 nephrectomy was performed in each group due to acute rejection. The mortality rate related to the surgical procedure in both groups in our study was zero. In the general survival and renal function at 6-month follow-up, there was no difference observed between the groups, supporting the assertion about the safety of our procedure compared with anastomosis of a short renal vein with iliac vein or common external iliac vein.

With our study, we attempted to offer our experience related to the extension of right renal vein as a safe procedure compared with the most commonly used kidney transplant: the anastomosis of a short renal vein with iliac vein or common external iliac vein. We recommend considering our procedure as an alternative option to decrease warm ischemia time, perform an easier vein anastomosis with the vena cava extension, and make the procedure comfortable for the surgeon.

Volume: 13 Issue: 2 April 2015

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