Pancreatic graft survival despite partial vascular graft thrombosis due to splenocephalic anastomoses

Anatomical basis for pancreas transplantation via isolated splenic artery perfusion: A literature review

The variability of vascular anatomy of the pancreas underlines the difficulty of its transplantation. Research regarding the consistency of anatomical variations shows splenic arterial dominance in most cases. This can significantly improve transplantation success. A systematic literature review was performed according to the quality standards described in the AMSTAR measurement tool and the PRISMA guidelines. We valuated existing literature regarding the vascularization and blood perfusion patterns of the pancreas in terms of dominance and variability. The collected data was independently analyzed by two researchers. Variance of vascular anatomy was seen to be underreported in literature, though significant findings have been included and discussed in this study, providing valuable insight into the dynamics of pancreatic perfusion and feasibility of transplantation on several different supplying arteries. The splenic artery (SA) has a high percentage of consistency in all found studies (over 90%). High frequency of anastomoses between arterial pools supplying the pancreas can mediate sufficient blood supply through a dominant vessel, such as the SA, which is present in most cases. Pancreatic transplantation with isolated SA blood supply can provide sufficient arterial perfusion of the pancreas for stable transplant viability due to high anatomical consistency of the SA and vast communications with other arterial systems.

Vascular Complications After Simultaneous Pancreas and Kidney Transplantation: A Case Report

A 51-year-old patient with type I diabetes and end-stage renal disease was qualified for a simultaneous kidney and pancreas transplant. The procedure was performed in a typical manner: arterial anastomosis to the right common iliac artery, the graft's portal vein with inferior vena cava, and side-to-side duodenal intestinal anastomosis. The kidney was implanted retroperitoneally. Six months after the transplant, the patient reported pain in the right lower abdomen, and imaging examinations revealed arterial anastomosis. Reconstruction of the right common iliac artery was performed with a Gore-Tex prosthesis and the pancreatic artery reanastomosed to the right external iliac artery. After the surgery, the function of the transplanted pancreas deteriorated, the level of C-peptide was decreased, and the patient required low doses of insulin. After another 8 months, the imaging studies revealed an aneurysm located in the bifurcation of the aorta up to the anastomosis of the pancreatic graft artery with the iliac artery. The patient was qualified for the implantation of an endovascular of 2 prosthesis, which improved the graft's function. After another 2 months, the presence of an aneurysm at the endovascular prosthesis was found again. The patient was requalified for endovascular prosthesis implantation. Currently, there is no aneurysm but the function of the pancreas graft is impaired, though the kidney graft function is good. Patients after simultaneous kidney and pancreas transplant are a group of patients with an increased risk of vascular complications. Treatment should take place in a multidisciplinary center.

Endovascular Interventions in Vascular Complications After Simultaneous Pancreas and Kidney Transplantations: A Single-Center Experience

Background

Vascular failures are serious complications in pancreas transplantation. Open surgery is a reliable and quick intervention method, but it carries a risk of infection and bleeding. Endovascular procedures are rare among patients after a SPK, but are becoming more frequently used. One of the main risks of the endovascular approach is that the renal function impairment caused by contrast agent.

Material/Methods

We performed a retrospective analysis of 200 transplanted pancreases at our center over the last 14 years. The analyses included those patients after pancreas transplantation who required the most challenging vascular interventions and ones that were non-standard for the procedure.

Results

Severe vascular conditions requiring endovascular intervention were observed in 3% of SPKs. In one retransplanted patient, there was an acute ischemia of the lower extremity due to the narrowing of the common iliac artery following a previous transplantectomy, above the new pancreas graft anastomoses. In another patient, local inflammation led to the disruption of the external iliac artery on the level of transplantectomy, caused severe bleeding, and we had to implement a stent-graft to reconstruct the iliac artery wall. A third patient had a pseudoaneurysm demanding further treatment with a stent-graft implemented into the femoral artery due to a pseudoaneurysm of the right external iliac artery.

Conclusions

Intravenous interventions in patients with a transplanted or retransplanted pancreas are safe and feasible. It is a technically demanding procedure, but the risk of kidney graft function deterioration, as well as of bleeding due to the high dose of heparin used, is lower than with open vascular surgery.

Pancreatic allograft thrombosis: Suggestion for a CT grading system and management algorithm

Pancreatic allograft thrombosis (PAT) remains the leading cause of nonimmunologic graft failure. Here, we propose a new computed tomography (CT) grading system of PAT to identify risk factors for allograft loss and outline a management algorithm by retrospective review of consecutive pancreatic transplantations between 2009 and 2014. Triple-phase CT scans were graded independently by 2 radiologists as grade 0, no thrombosis; grade 1, peripheral thrombosis; grade 2, intermediate non-occlusive thrombosis; and grade 3, central occlusive thrombosis. Twenty-four (23.3%) of 103 recipients were diagnosed with PAT (including grade 1). Three (2.9%) grafts were lost due to portal vein thrombosis. On multivariate analysis, pancreas after simultaneous pancreas-kidney transplantation/solitary pancreatic transplantation, acute rejection, and CT findings of peripancreatic edema and/or inflammatory change were significant risk factors for PAT. Retrospective review of CT scans revealed more grade 1 and 2 thromboses than were initially reported. There was no significant difference in graft or patient survival, postoperative stay, or morbidity of recipients with grade 1 or 2 thrombosis who were or were not anticoagulated. Our data suggest that therapeutic anticoagulation is not necessary for grade 1 and 2 arterial and grade 1 venous thrombosis. The proposed grading system can assist clinicians in decision-making and provide standardized reporting for future studies.

Techniques of pancreas graft salvage/indications for allograft pancreatectomy

PURPOSE OF REVIEW

Despite improvements in pancreas allograft outcome, graft complications remain a significant cause of morbidity and mortality. This review analyses the issues involved in the management of conditions that may require graft pancreatectomy, including the indications and techniques for graft salvage.

RECENT FINDINGS

With early recognition of graft complications, liberal use of radiological interventions, improved infection control, access to critical care and innovative surgical techniques, graft salvage is now feasible in many circumstances where graft pancreatectomy would previously have been necessary.

SUMMARY

The outcome of pancreas transplantation continues to improve with advances in the management of graft-threatening complications.

Functioning pancreas graft with thromboses of splenic and superior mesenteric arteries after simultaneous pancreas-kidney transplantation: a case report

Graft thrombosis is the most common cause of early graft loss after pancreas transplantation. The grafted pancreas is difficult to salvage after complete thrombosis, especially arterial thrombosis, and graft pancreatectomy is required. We describe a patient presenting with a functioning pancreas graft with thromboses of the splenic artery (SA) and superior mesenteric artery (SMA) after simultaneous pancreas-kidney transplantation (SPK). A 37-year-old woman with a 20-year history of type 1 diabetes mellitus underwent SPK. The pancreaticoduodenal graft was implanted in the right iliac fossa with enteric drainage. A Carrel patch was anastomosed to the recipient's right common iliac artery, and the graft gastroduodenal artery was anastomosed to the common hepatic artery using an arterial I-graft. The donor portal vein was anastomosed to the recipient's inferior vena cava. Four days after surgery, graft thromboses were detected by Doppler ultrasound without increases in the serum amylase and blood glucose levels. Contrast enhanced computed tomography revealed thromboses in the SA, splenic vein and SMA. Selective angiography showed that blood flow was interrupted in the SA and SMA. However, pancreatic graft perfusion was maintained by the I-graft in the head of the pancreas and the transverse pancreatic artery in the body and tail of the pancreas. We performed percutaneous direct thrombolysis and adjuvant thrombolytic therapy. However, we had to stop the thrombolytic therapy because of gastrointestinal hemorrhage. Thereafter, the postoperative course was uneventful and the pancreas graft was functioning with a fasting blood glucose level of 75 mg/dL, HbA1c of 5.1%, and serum C-peptide level of 1.9 ng/mL at 30 months post-transplantation.

Imaging spectrum after pancreas transplantation with enteric drainage

Since the introduction of pancreas transplantation more than 40 years ago, surgical techniques and immunosuppressive regiments have improved and both have contributed to increase the number and success rate of this procedure. However, graft survival corresponds to early diagnosis of organ-related complications. Thus, knowledge of the transplantation procedure and postoperative image anatomy are basic requirements for radiologists. In this article, we demonstrate the imaging spectrum of pancreas transplantation with enteric exocrine drainage.

Pancreas graft thrombosis: causes, prevention, diagnosis, and intervention

PURPOSE OF REVIEW

Pancreas graft thrombosis remains one of the most common reasons for pancreas transplant loss. Patients with a history of thrombotic events should be identified and evaluated for thrombophilia to identify transplant candidates at highest risk.

RECENT FINDINGS

Early after transplant, vascular thrombosis is multifactorial, but beyond 2 weeks, inflammation or acute rejection predominate as the cause of thrombosis. Most pancreas transplant centers utilize some form of anticoagulation following transplantation. Aspirin is highly recommended. Unfractionated or low-molecular-weight heparin is often administered, but some centers use heparin selectively and typically at low dose to avoid postoperative bleeding. Warfarin is less frequently given and its use should probably be limited to patients with thrombophilia.

SUMMARY

Thrombectomy, either surgical or percutaneous, may salvage the pancreas graft if performed early after the occurrence of thrombosis.

Enteroscopic biopsies in the management of pancreas transplants: a proof of concept study for a novel monitoring tool

BACKGROUND

Although percutaneous biopsies are considered to be the gold standard in diagnosing pancreas graft rejection, they are not performed routinely because of their association with severe complications. On the other hand, correct diagnosis of rejection is essential but may be difficult in cases of enteric drainage, particularly in patients with a pancreas transplant alone or a pancreas after kidney transplant.

METHODS

Pancreas recipients who underwent enteroscopy between May 2005 and September 2009 were included in this retrospective analysis. Biopsies were graded 0 to 4 for interstitial and vascular changes.

RESULTS

During the study period a total of 65 simultaneous pancreas-kidney transplants, 13 pancreas after kidney transplants and 4 pancreas transplants alone were performed. Sixty-three patients underwent a single enteroscopy, 10 had two, and 6 had three or more. Indications were protocol graft monitoring (n=73), graft dysfunction (n=17), enteric hemorrhage (n=9), or other (n=3). The duodenal segment was accessed in 76 instances (75%) with abnormal findings in 23. A total of 69 biopsies were obtained and revealed normal mucosa in 49 cases (71%). Histology showed signs of acute rejection in 11 cases. The upper gastrointestinal tract was also assessed, and, in 13 cases, additional pathologies were identified including gastroduodenitis (n=10), gastric/duodenal ulcer (n=2), and hemorrhagic esophagitis (n=1). No procedure-related complication occurred.

CONCLUSIONS

This series of enteroscopies demonstrates that the duodenal segment of a pancreatic graft is accessible using our implant technique, and thus permitting biopsies to be obtained and endoscopic interventions to be performed.

Early reexploration for suspected thrombosis after pancreas transplantation

BACKGROUND

Graft thrombosis is the most common cause of early graft loss after pancreas transplantation. Early reexploration may permit salvage or timely removal of the thrombosed graft.

METHODS

This was a retrospective review of 345 pancreas transplants performed at a single center between January 2003 and December 2009. Early reexploration was defined as within 1 week of pancreas transplantation.

RESULTS

Of the 345 transplants, there were 35 early reexplorations. The graft was compromised in 20 cases (57%): 10 venous thromboses, 3 arterial thromboses, 2 combined arterial and venous thrombosis, 2 thromboses secondary to allograft pancreatitis, and 3 cases of positional ischemia without thrombosis. Of these allografts, three reperfused once repositioned and six were successfully thrombectomized for a graft salvage rate of 45%. One of the thrombectomized grafts remained perfused but never functioned and was removed at retransplantation. The 10 remaining compromised grafts that were deemed unsalvageable and required allograft pancreatectomy. Nine of these recipients were retransplanted (eight within 2 weeks) and one was not a retransplantation candidate.

CONCLUSIONS

Reexploration for suspected graft thrombosis after pancreas transplantation resulted in a negative laparotomy rate of 43%, but permitted graft salvage in 45% of compromised grafts.