Objectives: Despite surgical and medical advances, vascular complications are still among the major concerns after renal transplant, with a reported incidence of 3% to 15%. We evaluated the incidence and management of our transplant team’s vascular complications over 40 years.
Materials and Methods: From November 1975 to the present, we have performed a total of 2594 renal transplant procedures. Of these, 1997 grafts (76%) were obtained from living donors, and 597 grafts (24%) were obtained from deceased donors. All renal transplant procedures, including those performed in pediatric patients, used the extraperitoneal approach to the contralateral iliac fossa. Revascularization was performed for all grafts. A single end-to-end internal iliac artery anastomosis was performed in 1082 patients (41.8%), an end-to-side external iliac artery anastomosis was performed in 1289 patients (49.7%), and an end-to-side common iliac artery anastomosis was performed in 66 patients (2.5%). In 157 procedures (6%), there were at least 2 renal arteries, and both internal iliac arteries or external iliac arteries were used for anastomosis.
Results: We observed 57 vascular complications (2.1%) in 54 renal transplant procedures. The most frequent complication was renal artery stenosis (n = 17; 0.6%). There were 8 instances of renal artery thrombosis (0.4%), 7 of renal artery kinking (0.3%), 5 of renal vein thrombosis (0.2%), 9 of renal vein kinking (0.5%), 3 of external iliac artery dissection (0.01%), 5 renal vein lacerations (0.2%), and 3 renal artery lacerations (0.01%). We performed urgent surgery for 41 vascular complications; 38 were managed successfully. Percutaneous interventional techniques were used successfully for 18 vascular complications.
Conclusions: The vascular complication rate in our patients is lower than that reported in the literature. Surgical complications can be minimized with careful transplant technique and close follow-up, as early diagnosis is crucial to early management and successful treatment of complications.
Key words : External iliac artery dissection, Kidney transplantation
Kidney transplant plays an important role in the treatment of end-stage renal disease, improving the quality of life and prolonging life itself. Despite surgical and medical advances, vascular complications are still among the major concerns faced after renal transplant (RT), with a reported incidence of 3% to 15%.1 Prophylactic correction during preoperative evaluation can obviate many problems; however, technical mishaps should be prevented at all stages of the transplant process, and careful postoperative monitoring is warranted. To minimize mortality and morbidity, all complications must be diagnosed early and managed appropriately. The aim of this study is to evaluate our transplant team’s incidence and management of vascular complications with RT procedures over 40 years.
Materials and Methods
We retrospectively reviewed patient records. From November 1975 to the present, our transplant team performed 2594 RT procedures at 2 different centers. We performed the first 321 RTs at Hacettepe University Hospital and the remaining 2239 at 3 different centers of Baskent University. Of these 2594 RTs, 1997 grafts (76%) were obtained from living donors and 597 grafts (24%) were obtained from deceased donors. We performed RT in 1816 male and 778 female patients (age range, 1-76 y). At the time of transplant, 309 patients (12%) were children, and 2285 (88%) were adults. Our immunosuppressive protocol from 1975 to 1987 included prednisone and azathioprine. After 1987, low-dose cyclosporine was added to the regimen. Since 1998, the maintenance immunosuppressive regimen has consisted of cyclosporine or tacrolimus and mycophenolate mofetil plus prednisone. We used induction therapy in 625 high-risk patients (daclizumab, n = 177; basiliximab, n = 448). High-risk status was defined as retransplant, deceased-donor RT, unrelated-donor RT, or maternal-donor RT.
All RT procedures, including those performed in pediatric patients, used the extraperitoneal approach to the contralateral iliac fossa. Revascularization was performed for all grafts. The anatomy and number of renal arteries and veins was noted from either conventional angiography or computed tomography angiography in living donors. In deceased donors, the anatomy of the renal artery and vein was defined during harvest surgery. The vascular anatomic variations in allografts were single artery (n = 2425; 93.8%), 2 renal arteries (n = 164; 6%), and more than 2 renal arteries (n = 5; 0.2%). A single end-to-end internal iliac artery anastomosis was performed in 1082 patients (41.8%), an end-to-side external iliac artery anastomosis was performed in 1289 patients (49.7%), and an end-to-side common iliac artery anastomosis was performed in 66 patients (2.5%). In 157 RT procedures (6%), there were at least 2 renal arteries, and both internal iliac arteries or both external iliac arteries were used for anastomosis. Arterial anastomosis was performed using the 4-quadrant running suture technique in 2187 RT procedures (85%).2 After December 2003, we began to use the corner-saving technique, and this was employed in 407 RT procedures (15%).3 We anastomosed the renal veins to the external iliac vein or common iliac vein, according to the diameter and position of the vessels. We used closed suction drainage in all patients. Postoperative renal function was monitored using routine daily biochemical testing (serum blood urea nitrogen and creatinine levels). Graft perfusion was followed using routine Doppler ultrasonography (US) examination.
We collected information on all vascular complications: renal artery stenosis (RAS), renal artery thrombosis (RAT), renal vein thrombosis (RVT), renal artery kinking, renal vein kinking, renal artery laceration, renal vein laceration, and external iliac artery dissection (EIAD).
We observed 57 vascular complications (2.1%) in 54 RT procedures. The most frequent was RAS (n = 17; 0.6%). We observed 8 instances of RAT (0.4%), 7 of renal artery kinking (0.3%), 5 of RVT (0.2%), 9 of renal vein kinking (0.5%), 3 EIADs (0.01%), 5 renal vein lacerations (0.2%), and 3 renal artery lacerations (0.01%). We performed urgent surgery for 41 vascular complications, and 38 were managed successfully. Percutaneous interventional techniques were used successfully for 18 vascular complications.
The clinical presentation of complications in the early postoperative period consisted of acute deterioration of graft function, acute reduction of urine output, sudden anuria, or bleeding. We performed surgery in 16 patients with renal artery or renal vein kinking, rearranging the graft position. A total of 8 patients with renal artery or renal vein laceration also underwent reoperation; unfortunately, in 3 of these patients, repair was impossible, and we proceeded with graft nephrectomy. We repaired 3 EIADs by replacing the external iliac artery with a polytetrafluoroethylene (PTFE) graft. Five of 8 patients with RAT underwent successful thrombectomy; the other 3 were managed using percutaneous angiography and stenting. One patient with RAT died of a pulmonary thromboembolism. Four patients with RVT were treated surgically with successful thrombectomy. One patient with RVT was managed using percutaneous angiography and stenting.
The most frequent vascular complication was RAS. We observed 17 instances, including 4 in teenage patients (age range, 13-57 y). We performed 19 renal artery anastomoses in the 14 patients with RAS, as 5 patients had 2 involved renal arteries. In 4 patients, both internal iliac arteries or both external iliac arteries were used for anastomosis; in 1 patient, 2 arteries were anastomosed to a single external iliac artery. In the patients with RAS, we performed 10 end-to-side 4-quadrant external iliac artery anastomoses, 8 end-to-end 4-quadrant internal iliac artery anastomoses, and 1 end-to-side corner-saving external iliac artery anastomosis. Three instances of RAS were seen in the first week after RT: 1 on the first and 2 on the second day after transplant. We performed urgent surgery in these 3 patients after confirming the diagnosis of RAS on RT angiography. All other instances of RAS were detected late after transplant (interval range, 3-84 mo); all were managed using percutaneous angiography and stenting.
Since Murray and associates performed the first successful organ transplant between twins in 1954, the field of kidney transplantation has evolved considerably. Although surgical complications can be minimized with detailed preoperative evaluation, careful transplant technique, early diagnosis, and early management, vascular complications are still among the major concerns after RT, with a reported incidence of 3% to 15%. Therefore, knowledge of the incidence, clinical manifestations, and management of vascular complications is crucial.
Significant progress has been made in methods of vascular anastomosis. The introduction of the Carrel patch vascular technique by Alexis Carrel in 1902 is considered among the most important developments in transplant surgery.4 In Turkey, the first living-donor kidney transplant was performed by Haberal and his team on November 3, 1975. Since then, Haberal has described different vascular anastomosis techniques. Between November 1993 and December 2003, he performed end-to-side or end-to-end anastomoses using the 4-quadrant running suture technique.2 Beginning in 2004, he defined the corner-saving renal artery anastomosis technique.3 He reports arterial complication rates of 0.35% for thrombosis and 0.7% for stenosis.
The most common vascular complication is RAS, with an estimated incidence of 19% to 23% in all transplant recipients.5,6 In our centers, the rates are 0.5% to 0.75%. The complication frequently presents with worsening or refractory hypertension, with or without graft dysfunction, in the absence of rejection, ureteric obstruction, or infection. Different locations and timing of disease onset may reflect different causes. For example, an anastomotic stenosis is most likely related to trauma to the donor or recipient vessels during retrieval, clamping, or suturing and usually arises early after the transplant. The diagnosis of RAS is made using US, magnetic resonance angiography, and angiography. Our preferred initial option for treatment is the interventional radiologic approach. When this is not successful, we resort to surgical reconstruction.7,8 In our 3 patients with RAS in the first week after RT, we performed urgent surgery. In the 14 patients with late RAS, we used percutaneous interventional techniques (Figure 1). About 50% of RAS is located at the anastomosis, and end-to-end anastomoses have a threefold higher risk than end-to-side anastomoses. Our RAS patients included 10 with end-to-side anastomoses.
Although vascular thrombosis is a rare complication, it is a major cause of early graft loss, accounting for up to one-third of graft loss within 1 month of RT and up to 47% within 2 to 3 months. The North American Pediatric Renal Transplant Cooperative Study cohort, with data collected from 1996 to 2001, lists thrombosis as the most common cause of early graft loss.4 The complication of RAT usually occurs soon after the transplant procedure. It is destructive, usually resulting in graft loss, and its incidence is reportedly either 0.2% to 7.5% or 0.5% to 3.5%.9 The incidence of RAT in children is higher than in adults. The most important signs of RAT are instantaneous cessation of urine output, due to the absence of graft perfusion, and the presence of worsening hypertension. In preemptive patients and patients with preoperative urine output, this sign is masked, and postoperative bedside Doppler US is recommended. The most common causes of RAT are technical issues, such as a faulty suture technique producing incomplete intimal reapproximation with secondary intraluminal fibrosis. Since November 1975, our transplant team has performed 2594 kidney transplants, with 8 instances of RAT (0.35%) seen during this period. Surgical exploration was performed in 5 patients and included thrombectomy, reperfusion, and reanastomosis procedures. The other 3 patients who developed RAT were treated with percutaneous transluminal angioplasty, thrombolysis, and intraluminal stent placement. Other factors predisposing to thrombosis are kinking or twisting of the renal artery, postoperative hypotension, a hypercoagulable state, atherosclerosis of the donor or recipient vessels, a wide disparity in vessel size, increased intrarenal pressure resulting from acute tubular necrosis, hydronephrosis, and cellular rejection. In our centers, 7 instances (0.3%) of renal artery kinking were seen and treated surgically to rearrange the graft position. All patients had normal renal function.
The complication of RVT usually occurs within the first 7 days after transplant. The incidence of RVT ranges from 0.1% to 8.2%, and it usually causes early graft loss.4,10 The clinical presentations of this condition are sudden oliguria or anuria accompanied by pain, hematuria, and life-threatening hemorrhage due to graft rupture. Renal Doppler US confirms an increase in renal volume and absence of venous flow.11 In our clinic, we routinely use Doppler US on the third and seventh postoperative days to diagnose early vascular problems. In addition, Doppler US must be performed during the immediate postoperative period if there is clinical suspicion for, or biochemical evidence of, renal dysfunction. In our series, we observed 5 patients (0.2%) who developed RVT after RT. All were treated with urgent thrombectomy. Unfortunately, 2 procedures were unsuccessful, and the grafts were lost.
Traumatic EIAD following RT is a rare complication, but it should be managed urgently due to its devastating effect on graft- and lower-limb circulation. EIAD is seen more often in recipients with diabetes mellitus and comorbid diseases. Recipients with EIAD should be treated immediately using either percutaneous angioplasty or surgical reconstruction. The literature describes some patients treated with percutaneous angioplasty and stenting or endarterectomy.12 The other option for treatment is reconstruction with a PTFE graft. In our series, we only noted EIAD in 3 patients. All were traumatic EIAD from vascular clamping, and we treated them with the PTFE graft-reconstruction technique (Figure 2), in which the dissected part of the external iliac artery is resected and replaced with a PTFE graft that is 6 to 8 cm in length and 8 mm in diameter, using 6-0 Prolene. The renal artery is then anastomosed to the PTFE graft with continuous 7-0 Prolene.
All 3 patients are doing well with normal kidney function.
Despite significant advances in the field, vascular complications still represent an important cause of morbidity and mortality after RT. Many problems can be avoided through prophylactic correction of abnormalities detected during preoperative evaluation. It is critical that technical mishaps at all stages of the transplant process (eg, donor nephrectomy, bench work preparation, implantation) should be prevented, and careful postoperative monitoring should be carried out to facilitate early diagnosis and management.
Volume : 15
Issue : 1
Pages : 79 - 83
DOI : 10.6002/ect.mesot2016.O65
From the 1Department of Transplant Surgery and the 2Department of Radiology,
Baskent University, Ankara, Turkey
Acknowledgements: The authors have no financial disclosures and have no conflicts of interest to disclose.
Corresponding author: Prof. Mehmet Haberal, MD, FACS (Hon), FICS (Hon), FASA (Hon), Department of General Surgery, Baskent University, Ankara, Turkey
Phone: +90 312 212 7393
Figure 1. Angiography
Figure 2. Angiographic and Gross Findings