Pancreatico-renal composite transplant: a new technique designed to decrease pancreatic graft thrombosis

A Case Report of Modified Pancreatic Transplantation With a Limited Splenic Arteriovenous Fistula to Elude Thrombosis

In classic pancreatic transplantation, the splenic artery and vein are ligated at the tail of the pancreas graft. This leads to slowed blood flow in the splenic vein and may cause thrombosis and graft loss. In this study, a patient received a pancreas after kidney transplantation. A modified surgical technique was used in the pancreatic graft preparation. The donor splenic artery and vein were anastomosed end to end at the tail of the pancreas. The splenic artery near the anastomosis was partially ligated, and an effective diameter of 2 mm was reserved to limit arterial blood pressure and flow. The patient recovered very well. Contrasted computed tomography scans on days 11 and 88 after pancreas transplantation indicated sufficient backflow of the splenic vein. We believe that this procedure may avoid the risk of splenic vein thrombosis after pancreas transplantation. This modified technique has not been reported in clinical cases previously and may help reduce the risk of thrombosis after pancreas transplantation.

Pancreas Transplantation in a Single Center: Risk Factors Associated With Pancreatic Allograft Thrombosis

BACKGROUND

Pancreas transplantation remains a challenging procedure for small and medium-sized transplants teams, despite improvements in graft survival. Data regarding the impact of the procurement team's experience on the outcomes of pancreas transplant are lacking. The objective of this study was to evaluate risk factors that lead to pancreatic allograft thrombosis, especially the experience of the pancreas procurement team.

METHODS

A retrospective study of 137 patients who underwent pancreas transplantation between March 2005 and May 2017 was conducted. Donor's and recipient characteristics were evaluated as well as their relationship to pancreatic allograft thrombosis. Cases were divided according to the number of pancreas procurements previously done by the procurement surgeon: group 1 (30 to 40 retrievals) and group 2 (≥40 retrievals).

RESULTS

Simultaneous pancreas-kidney transplants accounted for 89.8% of cases (n = 123). Surgeons from group 2 performed 62.8% (n = 86) of the procurements. The graft was removed in 19 cases (13.8%) due to thrombosis. In univariate analysis, lower experience of the retrieval team was associated with allograft loss (P = .04). In multivariate analysis, donor intensive care unit time ≥5 days (P = .03) and lower experience of the procurement team were associated with increased risk of pancreatic allograft thrombosis (P = .02), whereas recipient's age from 30 to 40 years (P = .018) or ≥40 years (P = .02) was found as a protective factor.

CONCLUSIONS

Pancreatic allograft thrombosis remains an important cause of graft loss in pancreas transplantation. Recipient's age, prolonged donor intensive care unit time, and lower experience of the procurement team directly influence pancreatic allograft thrombosis.

Effective Technique for Pancreas Transplantation by Iliac Vascular Transposition, Without Heparin-Based Anticoagulation Therapy

BACKGROUND

To evaluate patients undergoing a new procedure, iliac vascular transposition, in pancreas transplantation regarding the risk of thrombosis and graft survival without heparin-based anticoagulation therapy.

METHODS

Iliac vascular transposition (IVT) involves changing the positions of the external iliac artery and vein relative to each other. In this study, this technique was evaluated in patients undergoing the procedure compared with patients not undergoing the procedure (iliac vascular parallel (IVP) group).

RESULTS

No patients received prophylactic heparin therapy. Two patients in the IVP group (n = 26) developed complete thrombosis and six developed partial thrombosis, compared with no patients with complete thrombosis and one with partial thrombosis in the IVT group (n = 29). The cumulative incidence of thrombosis was significantly higher in the IVP group (p < 0.01). Cox regression revealed that not receiving iliac vascular transposition was the only significant risk factor for thrombosis (odds ratio: 10.1, 95% confidence interval: 1.27-81.2; p = 0.03). One-year graft survival was significantly better in the IVT group vs IVP group (p = 0.03).

CONCLUSIONS

IVT in pancreas transplantation is a simple technique that results in a lower thrombosis risk and better graft survival rates without heparin-based anticoagulation therapy.

Early protocol computer tomography and endovascular interventions in pancreas transplantation

BACKGROUND

Early vascular complications following pancreatic transplantation are not uncommon (3%-8%). Typically, cross-sectional imaging is requested in response to clinical change. We instituted a change in protocol to request imaging pre-emptively to identify patients with thrombotic complications.

METHODS

In 2013, protocol computer tomography angiography (CTA) at days 3-5 and day 10 following pancreas transplantation was introduced. A retrospective analysis of all pancreas transplants performed at our institution from January 2001 to May 2019 was undertaken.

RESULTS

A total of 115 patients received pancreas transplants during this time period. A total of 78 received pancreas transplant without routine CTA and 37 patients with the new protocol. Following the change in protocol, we detected a high number of subclinical thromboses (41.7%). There was a significant decrease in invasive intervention for thrombosis (78.6% before vs 30.8% after, p = .02), and graft survival was significantly higher (61.5% before vs 86.1% after, p = .04). There was also a significant reduction in the number of graft failures (all-cause) where thrombosis was present (23.4% before vs 5.6% after, p = .02). Patient survival was unaffected (p = .48).

CONCLUSIONS

Implementation of early protocol CTA identifies a large number of patients with subclinical graft thromboses that are more amenable to conservative management and significantly reduces the requirement for invasive intervention.

Short and long-term outcomes of systemic drainage to IVC: a new technique for pancreas transplantation

Ninety-eight percent of the whole pancreas does not serve the purpose of pancreatic transplantation and it is a major cause of surgical complications. Up to 30% of pancreas transplant recipients experience surgical complications and require reoperation. Graft thrombosis and pancreatitis are the most common complications of pancreas transplantation (PT). Thus, different surgical techniques have been described to overcome the surgical hurdles and reduce surgical complications. In this study, for the first time, we report short- and long-term outcomes of PT with inferior vena cava (IVC) venous drainage. Forty-five PTs (22 simultaneous pancreas and kidney [SPK] transplantations and 23 pancreas after kidney [PAK] transplantations) were performed with this technique in our center. Sixty-eight percent of the donors were imported from outside of our area after they were declined by their local transplantation center. Patient and graft survival rates were 100% at 1 year. No graft thrombosis or pancreatitis occurred with this technique. Six patients (13.3%) required reoperation (3 bleeding, 2 anastomotic leak, and 1 small bowel perforation). No patient or graft loss occurred due to surgical complications. We conclude that this technique provides fast and easy dissection of the venous drainage of the PT without the need of complete occlusion of venous outflow. Surgical complication rates were lower with this technique compared with other reported techniques.

Retrieval of the pancreas allograft for whole-organ transplantation

Proper pancreas retrieval during multi-organ recovery is one of the cornerstones of technically successful whole-organ pancreas transplantation. With evolving surgical approaches for organ retrieval and implantation, it has become standard to procure the pancreas in conjunction with other abdominal organs without compromising either vasculature, graft quality, or transplant outcomes. This review summarizes the major steps required for proper whole-organ retrieval of the pancreas allograft with suggestions and tips whenever alternative approaches are available.

The use of venous jump grafts in pancreatic transplantation - no difference in patient or allograft outcomes - an update of the UNOS database

Venous jump grafts are used in pancreas transplantation to salvage a pancreas with a short portal vein or to facilitate an easier anastomosis. There have been no large studies evaluating the safety of venous jump grafts in pancreas transplantation. We analyzed the UNOS database to determine whether venous jump grafts are associated with graft loss or patient death. Data from UNOS on all adult pancreas transplant recipients 1996-2012 were analyzed. Venous extension grafts were used in 2657 cases; they were not in 18 124. Kaplan-Meier/product-limit estimates analysis demonstrated similar patient survival (p < 0.641) and death-censored graft survival (p < 0.351) at one, three, five,10, and 15 yr between subjects with and without venous jump grafts. There was a statistically significant difference in one-yr unadjusted patient survival between the venous extension graft (94.9%) and the no-venous extension graft (95.8%) groups (p < 0.045) and a borderline difference in one-yr graft survival between the venous extension graft (84.1%) and the no-venous extension graft (82.6%) groups (p < 0.055). There was no significant difference in patient survival or allograft survival at the three-, five-, 10-, and 15-yr intervals. The use of venous jump grafts is not associated with increased graft loss or mortality.

Impact of blood amylase peak over vascular graft thrombosis in pancreas transplantation

BACKGROUND

Vascular graft thrombosis (VGT) is still the achuilles heel in pancreas transplantation (PT); it is the main cause of nonimmunologic graft loss. Early diagnosis is essential to avoid transplantectomy. The aim of our study was to analyze the peak amylase during the first 3 days after PT as risk factor for VGT.

METHODS

This retrospective study included 58 pancreas transplants in 55 patients from January 2007 to November 2011. They underwent an anticoagulation protocol based on unfractionated heparin and low-molecular-weight heparin. The technique consisted of enteric drainage and systemic venous drainage. The primary endpoint was VGT with consideration of multiple relevant variables. The maximum amylase level was determined during the first 3 days after transplantation. A receiver operating characteristic analysis was performed to establish a cutoff point as (mean plus one standard deviation; 745 mg/dL), calculating the sensitivity, specificity, and predictive values.

RESULTS

Recipient characteristics were 71% males with an overall mean age of 39 years (range, 23-55) and body mass index 24 (range, 19-36). The donor sex was similar. Mean donor age was 32 years with occurrences of hypotension in 9%, cerebrovascular brain death in 46%. Mean ischemia time was 10 hours and 45 minutes. Mean blood amylase peak was 395 mg/dL. Seven VGT cases were diagnosed during the postoperative period including six with complete thrombosis requring transplantectomy. Bivariate analysis showed the group of subjects with amylase levels above 745 mg/dL to display on eight-fold greater risk for VGT (odds ratio = 8.6; P = .032). The area under the curve of blood amylase peak during the first 3 days to detect VGT was 0.630 (95% confidence interval 0.41-0.84).

CONCLUSIONS

A blood amylase peak above 745 mg/dL in the first 3 days after transplantation was associated with risk for VGT.

Early pancreas allograft thrombosis

OBJECTIVES

To determine factors associated with early pancreatic allograft thrombosis (EPAT). Thrombosis is the leading non-immunological cause of early pancreatic allograft failure. Multiple risk factors have been postulated. We hypothesized that recipient perioperative hypotension was a major risk factor and evaluated the correlation of this and other parameters with EPAT.

METHODS

We retrospectively reviewed the records of the 118 patients who received a pancreatic allograft at our center between October 1992 and January 2010. Multiple donor and recipient parameters were analyzed as associates of EPAT by univariate and multivariate analysis.

RESULTS

There were 12 episodes of EPAT, resulting in an incidence of 10.2%. On univariate analysis, EPAT was associated with perioperative hypotension, vasopressor use, and neuropathy in the recipient (p ≤ 0.04 for all). On multivariate analysis corrected for age, sex, and peripheral vascular disease, only vasopressor use retained a significant association with EPAT with a hazard ratio of 8.74 (CI 1.11-68.9, p = 0.04). Factors associated with vasopressor use included recipient ischemic heart disease, peripheral vascular disease, retinopathy or neuropathy, and any surgical complication.

CONCLUSIONS

Significant hypotension, measured by the need for perioperative vasopressor use was associated with EPAT, suggesting that maintenance of higher perfusion pressures may avoid this complication.

A novel technique of portal-endocrine and gastric-exocrine drainage in pancreatic transplantation

BACKGROUND

Pancreas transplant (PT) is an established treatment for patients with diabetes mellitus. Diagnosis of rejection has continued to be problematic. In 2007, a new technique of PT with gastric exocrine (P-G) drainage was first performed at our institution. This technique facilitates access to pancreas allograft. The purpose of this study was to compare our experience with PT using P-G technique and the technique of portal enteric (P-E) with venting jejunostomy.

STUDY DESIGN

Thirty patients who underwent PT between 2007 and 2009 (G-I) and 30 consecutive patients before this time (G-II) were studied. In both groups arterial and venous anastomosis was similar to standard P-E technique. In G-I, the end of allograft jejunum was anastomosed to the anterior aspect of the stomach. In the G-II, allograft duodenum was anastomosed to the Roux-en-Y and end of Roux-en-Y was brought out as venting jejunostomy.

RESULTS

Donor and recipient demographic data, number of antigen matches, and immunosuppressant were similar in both groups. All patients achieved euglycemia. In G-I, 3 patients underwent pancreatectomy, 2 owing to vessel thrombosis and 1 owing to chronic rejection. Two patients died with functioning pancreatic allografts. In G-II, 1 pancreas was removed owing to vessel thrombosis. Seven patients with cytomegalovirus and 4 patients with rejection in G-I were diagnosed with endoscopy of allograft duodenum. One-year patient and graft survivals were similar.

CONCLUSIONS

This technique has proven to be safe with good patient and allograft survival. Access to donor duodenum and pancreas allograft via endoscopy is unique to this technique and provides the added advantage of life-long easy access to allograft.

Pancreas allograft thrombosis

Thrombosis of the transplanted pancreas is a common and often catastrophic event. Predisposing factors include the hypercoagulable state of many patients with diabetic renal failure, preservation-related graft endothelial injury, and low-velocity venous flow. Clinical management includes optimization of modifiable risk factors, controlled anticoagulation, graft monitoring, and early therapeutic intervention.

Surgical techniques for pancreas transplantation

PURPOSE OF REVIEW

Pancreas transplantation reproducibly induces insulin independence in beta-cell penic diabetic patients. The difference between full insulin independence, partial graft function, and graft loss, mostly results from technical failure, graft rejection, and patient death with function graft. The purpose of this review is to examine recent surgical advances and discuss their contribution to improved graft function.

RECENT FINDINGS

Few actual surgical innovations were described in the period reviewed. Duodenoduodenostomy is an interesting option for drainage of digestive secretions, when the pancreas is placed behind the right colon and is oriented cephalad. The main advantage of this technique is easy endoscopic assessment of donor duodenum but, when allograft pancreatectomy is necessary, repair of native duodenum may be troublesome. Selective revascularization of the gastroduodenal artery, at the back-table, possibly improves blood supply to the head of the pancreas graft and duodenal segment. There is no proof that this additional maneuver is always beneficial, although it can be graft saving in case of poor segmental graft perfusion.

SUMMARY

Transplant surgeons should be familiar with all techniques for pancreas transplantation. Long-term graft function is possible only after technically successful pancreas transplantation. There is clearly a need for more objective assessment and standardization of surgical techniques for pancreas transplantation.

Use of small donors (<28 kg) for pancreas transplantation

OBJECTIVE

Small donors have long been considered a potential source of organs for simultaneous pancreas-kidney transplantation (SPK) and pancreas transplantation alone (PTA). Our aim was to analyze our experience with SPK and PTA using small donors weighing <28 kg.

PATIENTS AND METHODS

Between September 2006 and October 2008, we performed 68 SPK, 3 PTA, and 3 pancreas after kidney transplantations (PAK). All recipients were adults with type 1 diabetes mellitus, including 8 who received small donor organs (<28 kg): 6 SPK and 2 PTA. We used 3 graft combinations for SPK: pancreas and single kidney; pancreas and en bloc kidneys; and en bloc dual kidney-pancreas. In contrast, we used conventional grafts for PTA. Mean weight among donors was 20.82 kg (range, 9.6-27 kg).

RESULTS

We observed neither delayed graft function nor mortality. At a follow-up of approximately 281 days, all patients were free of insulin and dialysis treatments.

CONCLUSIONS

Kidneys and pancreas from donors weighing <28 kg can be used in adult type 1 diabetic patients with excellent results. These small pediatric donors enabled us to enlarge the number of transplantations by 10.81%.

Exocrine drainage into the duodenum: a novel technique for pancreas transplantation

Simultaneous pancreas-kidney transplantation is the treatment of choice for patients suffering from type 1 diabetes mellitus and end-stage renal failure secondary to diabetic nephropathy. Until 1995, about 90% of pancreas transplantations were performed with exocrine drainage into the bladder. Since then the proportion of pancreas transplants with enteric drainage increased steadily because of frequency of complications and long-term disadvantages of bladder drainage. However, the use of enteric drainage removes the opportunity to monitor pancreatic allograft function either by measuring urinary amylase or by carrying out biopsy via cystoscopy. We report a new technique of exocrine pancreatic drainage into the recipient duodenum. This modification places the pancreas graft including the duodenal anastomosis in a retroperitoneal location and, importantly, allows easy graft monitoring via gastroscopy.