Pancreas transplant salvage after acute venous thrombosis

Clinical outcomes associated with the early postoperative use of heparin in pancreas transplantation

BACKGROUND

Graft thrombosis following pancreas transplantation is the leading non-immunologic cause of graft loss. Routine systemic anticoagulation is controversial because of an increased bleeding risk.

METHODS

This was a retrospective, single-center analysis including all pancreas transplants performed over 9 years evaluating the use of low-dose heparin in the early postoperative period. Clinical outcomes were partial and complete graft thrombosis within 30 days, bleeding events, relaparotomy rates, and 30-day graft and patient survival. Multivariate regression analysis was performed to identify risk factors for early graft loss resulting from thrombosis.

RESULTS

One hundred fifty-two patients were included, 52 in the heparin group. The overall complete thrombosis rate was 13.1%, 10% in those who received heparin, and 15% in those who did not. Partial thrombosis was higher in the heparin group (10% vs. 3%). Higher relaparotomy rates were seen in the heparin group (29% vs. 22%); however, bleeding events were similar between groups. Graft and patient survival at 30 days were similar between groups; however, there was a trend toward higher graft survival in the heparin group. Heparin showed a trend toward a protective benefit for early graft loss resulting from thrombosis in all multivariate regression models.

CONCLUSION

These data suggest low-dose heparin early in the postoperative period may provide a protective benefit in the prevention of early graft loss resulting from thrombosis, without an increased risk of bleeding.

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.

Pancreatic transplantation: surgical technique, normal radiological appearances and complications

Pancreas transplantation is a surgical treatment for diabetes mellitus. More than 23,000 pancreas transplants have now been reported to the International Transplant Registry (IPTR). Early diagnosis and therapy for graft-related complications are essential for graft survival. Radiologists must therefore understand the surgical procedure and the potential complications. During the course of this review, we will illustrate the normal post-operative anatomy and the imaging appearances of common potential complications.

Complications after pancreas transplantation

PURPOSE OF REVIEW

The history of transplantation of the pancreas, unlike that of transplantation of other abdominal organs, has largely been shaped by the associated surgical complications. After more than three decades of progress, surgical-technical pancreas graft failure rates have decreased to approximately 8%. The most recent developments in this area are systematically reviewed in this article.

RECENT FINDINGS

Vascular graft thrombosis remains, by far, the most common cause of technical graft failure. Recent reports suggested that pancreas preservation with histidine-tryptophan-ketoglutarate solution (HTK) might be a risk factor for reperfusion pancreatitis, graft thrombosis and decreased short- and long-term graft survival. It remains unclear whether these results are, at least in part, related to HTK flush volumes and extended preservation (e.g.,>12 h). For selected thrombosed pancreas grafts, there has been renewed interest in pharmacological, interventional, and surgical salvage. For selected recipients with early pancreas graft thrombosis not amenable to a salvage intervention, transplant pancreatectomy in conjunction with immediate retransplantation has emerged as a viable option. For graft thrombosis prevention, the enhanced backtable pancreas vascular reconstruction techniques (e.g., gastroduodenal artery revascularization) proposed by some authors await more formal study. For prevention of native vascular complications in high-risk recipients, several technical modifications have been reported. Developments with respect to other surgical complications (wound infection, pancreatitis, leak, and bleeding) have been more incremental.

CONCLUSION

Recent evidence underscores the importance of judicious donor and recipient selection and of optimization of preservation and surgical factors for excellent short- and long-term pancreas transplant outcomes.

Relaparotomy after pancreas transplantation: causes and outcomes

INTRODUCTION

Surgical complications after pancreas transplantation, and subsequently relaparotomies, are frequently associated with graft loss, important morbidities, and occasionally patient death.

PATIENTS AND METHODS

From March 1995 to September 2008, 118 diabetic patients underwent pancreas transplantation: 109 simultaneous pancreas-kidney and nine pancreas after kidney. There were 68 men and 50 women. Mean age at transplantation was 37.8 +/- 7.8 years (range = 25-66). We analyzed donor and recipient characteristics, rate of relaparotomies, risk factors, as well as patient and graft survivals.

RESULTS

Forty patients (33.9%) underwent one or more relaparotomies. The causes for relaparotomy were: graft thrombosis in 15 patients (12.7%), bleeding in 14 (11.9%), duodenal stump leak in 7 (5.9%), severe pancreatitis and/or abscess in 5 (4.2%), and small bowel obstruction in 3 (2.5%). Graft pancreatectomy was performed in 52.5% (21 patients). The causes of graft loss were: graft thrombosis in 15 patients (12.7%), bleeding in 14 (11.9%), and duodenal stump leaks in 7 (5.9%). Mortality rate after relaparotomy was 3.38% (four patients). Relaparotomy rate for thrombosis was higher among the portoiliac than the portocaval vein anastomosis group (20.0% vs 10.2%; P = NS), and significantly higher for the bladder drainage than the enteric drainage technique (18.2% vs 5.8%; P < .05). Patients without relaparotomy experienced a significantly higher 5-year graft survival rate than those who underwent relaparotomy (87.2% vs 37.9%; P < .001), but 5-year patient survivals were similar (96.8% without relaparotomy vs 89.6% with relaparotomy).

CONCLUSIONS

Abdominal complications and the necessity for relaparotomy were associated with important morbidity and significantly reduced pancreas graft survival.

Pancreas transplants

Cadaveric, whole pancreas transplantation has proved an effective therapy in the treatment of long-standing type 1 diabetes mellitus and is capable of achieving an insulin-independent eugyclaemic state. As a result, this procedure is being increasingly performed. However, the surgical procedure is complex and unfamiliar to many radiologists. Imaging with computed tomography (CT) and magnetic resonance imaging (MRI) gives excellent results and can be used confidently to diagnose vascular, enteric, and immune-mediated complications. We present a review of the normal post-transplantation appearance and the features of early and late complications.

Evaluation of vascular complications of pancreas transplantation with high-spatial-resolution contrast-enhanced MR angiography

PURPOSE

To retrospectively evaluate high-spatial-resolution contrast material-enhanced three-dimensional (3D) magnetic resonance (MR) angiography for assessment of vascular complications of pancreas allografts.

MATERIALS AND METHODS

The institutional review board approved the study and waived the requirement for informed patient consent owing to the retrospective nature of the study with use of an anonymous-subject database. The study was HIPAA compliant. The clinical and MR angiography findings in 11 patients (eight men, three women; mean age, 43 years; age range, 30-54 years) who had a history of pancreatic transplant dysfunction and underwent a total of 13 contrast-enhanced 3D MR angiography examinations were retrospectively reviewed. Comparison with conventional angiography findings was possible for four MR angiography examinations, comparison with surgical findings was possible for two examinations, and clinical follow-up was possible for all examinations. Two observers in consensus and blinded to the clinical results performed image analysis of the arterial and venous segments. Classification agreement was assessed with quadratic weighted kappa statistics.

RESULTS

Ten MR angiography examinations revealed vascular complications or signs suggestive of rejection. Only three examinations were considered to have completely normal results. All major complications were detected and included complete or partial arterial graft occlusion, stenosis of the arterial Y-graft caused by a kink, complete venous thrombosis, and arteriovenous fistula with pseudoaneurysm formation. For 46 arterial segments and 15 venous segments with angiographic and/or surgical comparison, overall agreement with MR angiography findings was nearly perfect (mean kappa, 0.983; standard error of the mean, 0.128).

CONCLUSION

High-spatial-resolution MR angiography of pancreas allografts enables assessment of the arterial and venous vascular anatomy and can be used to reliably identify clinically relevant vascular complications.

Incidence of Pancreas Graft Thrombosis in Portoiliac and Portocaval Venous Anastomosis

BACKGROUND

Pancreas graft thromboses represent more than 70% of all technical failures; multiple risk factors have been implicated. We analyzed the thrombosis rates using portoiliac versus portocaval vein anastomoses.

PATIENTS AND METHODS

The series includes 53 patients who underwent pancreas transplantation: 49 simultaneous pancreas-kidney and 4 pancreas after kidney. There were 27 men and 26 women, of mean age of 37.2 +/- 7.0 years. We compared two groups of recipients that were classified according to venous anastomosis: (A) portoiliac (n = 30), and (B) portocaval (n = 23).

RESULTS

The recipients did not show significant differences in age, gender, or duration of diabetes mellitus, but body mass index was significantly higher among the portocaval group. A bladder-drained pancreas technique was more frequently performed in the portoiliac group (93% of patients) versus an enteric-drained pancreas in the portocaval group (81%; P < .001). Heparinization was performed in 12 recipients: 11 (36.6%) in the portoiliac group and 1 (4.3%) in the portocaval group (P < .01). Vascular graft thrombosis (venous in six and arterial in one) developed in seven patients (13.2%) all in the portoiliac group (23%) (P < .02). Two-year patient survival was 93% in the portoiliac group and 94% in portocaval group (P = NS). Two-year graft survival was 66.6% in the portoiliac group and 85.9% in portocaval group (P = .07).

CONCLUSION

There was no graft thrombosis among patients with a portocaval vein anastomosis.

Vascular complications of pancreas transplantation

OBJECTIVE

The purpose of our study was to focus on the early diagnosis and treatment of vascular complications after simultaneous pancreas-kidney (SPK) transplantation. Description of the technique for salvage of the graft after venous thrombosis (VT) is also provided.

METHODS

From July 1994 to December 2002, 14 patients of 206 SPK transplant recipients had partial VT. Partial splenic VT (PSVT) was documented in 10 patients (4.8%), two had complete thrombosis of the splenic vein, one partial superior mesenteric thrombosis, and one developed partial thrombosis of the splenic and superior mesenteric vein. Four patients developed complete VT of the pancreas allograft and one superior mesenteric artery thrombosis. Our experience with four arteriovenous fistulae is also reported. The immunosuppression included tacrolimus, steroids, and monoclonal antibody to the IL-2 receptor. Thymoglobulin was introduced in June 2000 in our protocol combined with rapamycin or mycophenolate mofetil. These cases were identified following the intravenous (iv) use of tacrolimus with or without anti-IL-2R therapy. One case of complete VT is also reported one month following transplantation in a recipient with high rapamycin levels. Diagnosis was established during routine color Doppler ultrasonography.

RESULTS

Partial VT was effectively treated with anticoagulation. Complete VT required surgical thrombectomy. In our series, the pancreas was salvaged successfully in all patients with the technique described here.

CONCLUSION

Early diagnosis of vascular complications after pancreas transplantation is of paramount importance for the appropriate treatment with organ salvage. Based on our experience, we suggest that VT can be effectively treated with anticoagulation. Aspirin is sufficient for PSVT.

Treatment and outcome of pancreatic venous graft thrombosis after kidney--pancreas transplantation

BACKGROUND

Pancreas venous graft thrombosis after transplantation is the main non-immunological cause of graft failure and usually results in pancreatectomy. Duplex Doppler ultrasonography is the primary imaging technique for monitoring vascular patency after pancreas transplantation. This study reports the results of rescue treatments for pancreas graft thrombosis after simultaneous pancreas--kidney transplantation.

METHODS

One hundred and ninety-six patients with insulin-dependent diabetes mellitus received a simultaneous pancreas--kidney transplantation. Venous graft thrombosis was diagnosed in 25 of these patients based on Doppler ultrasonographic findings.

RESULTS

Total venous graft thrombosis was diagnosed in 20 symptomatic patients, of whom 14 required graft pancreatectomy. Surgical thrombectomy was attempted in six patients with preserved arterial supply and was successful in four. Partial venous graft thrombosis was diagnosed in five asymptomatic patients; one also had partial splenic artery thrombosis. Rescue graft procedures included systemic anticoagulation (one patient), arterial thrombolysis (one) and venous thrombolysis and/or mechanical venous thrombectomy (four episodes in three patients). Graft rescue was achieved in three patients treated by venous thrombolysis/thrombectomy.

CONCLUSION

Doppler ultrasonography allows the appropriate selection of rescue treatment based on the findings of total or partial thrombosis.

Partial venous thrombosis of the pancreatic allografts after simultaneous pancreas-kidney transplantation

Despite new advances in transplantation, complete venous thrombosis (VT) of the pancreas after simultaneous pancreas kidney (SPK) transplantation usually results in graft loss. Data are limited regarding the outcome and treatment of partial VT of the pancreas allograft. From July 1994 to December 1999, 126 patients with IDDM/end-stage renal disease underwent SPK with systemic bladder drainage at the University of Miami. We retrospectively reviewed our experience regarding the outcome and treatment options of partial VT of the pancreas allografts. From July 1994 to April 1997, partial VT was not seen in the first 66 SPK patients induced with anti-CD3 rnAb and oral or intravenous (i.v.) tacrolimus (TAC) in the operating room. From May 1997 to June 1999, 14 (29%) out of 48 patients had VT. These cases were identified following the i.v. use of TAC with anti-IL-2R antibody-induction therapy (7/15) or without (7/33). Partial thrombosis of the splenic vein (PTSV) was documented in 10 patients, 2 had complete thrombosis of the splenic vein (CTSV), 1 had partial thrombosis of the superior mesenteric vein (PTSMV), and 1 patient had PTSV and PTSMV. These were identified incidentally during routine color Doppler ultrasonography (CDU). None of these SPK recipients demonstrates a change in clinical parameters. The first 8 patients were systemically heparinized, followed by oral anticoagulation, except 1 patient with CTSV. He progressed to complete thrombosis of the pancreas allograft and was treated with percutaneous thrombectomy and urokinase infusion, followed by heparinization and oral anticoagulation. One patient required exploration for bleeding. In an attempt to reduce the morbidity of heparinization, we treated the next 6 patients with PTSV with aspirin followed by serial CDU. All 14 patients had preservation of the endocrine and exocrine pancreatic functions. CDU showed resolution with recanalization of the thrombosed vein(s). From July 1999 to December 1999, 12 SPK recipients were administered TAC orally with or without induction therapy with anti-IL-2R antibody. So far, in this group, VT has not been identified. In summary, a total of 14 out of 126 patients (11%) had isolated VT with a mean follow-up of 36.4 months. Based on our experience, we suggest that extensive VT after pancreas transplantation, including splenic and superior mesenteric VT, be treated with heparin and subsequent oral anticoagulation for 3 months. For more limited, partial splenic VT, aspirin may be sufficient. Follow-up CDU is critical for a successful outcome. The i.v. use of TAC appears to be a risk factor for the increased incidence of VT. Currently, using IL-2rmAb as induction, TAC is started orally on postoperative days 3 or 4 and aspirin on postoperative day 2.

Venous thrombosis and occlusion after pancreas transplantation: evaluation with breath-hold gadolinium-enhanced three-dimensional MR imaging

OBJECTIVE

We describe the imaging findings of venous thrombosis and occlusion after pancreatic transplantation in five patients who underwent multiphasic breath-hold gadolinium-enhanced three-dimensional MR imaging.

CONCLUSION

Venous thrombus appeared as serpetine voids within the graft parenchyma or at the venous anastomosis during the venous phase of MR imaging. Nonenhancement or heterogeneous enhancement of graft parenchyma corresponded to glandular necrosis at pancreatectomy in two patients. Initial sonographic evaluation was nondiagnostic of venous thrombosis in two of five patients. Multiphasic breath-hold gadolinium-enhanced three-dimensional MR imaging of pancreatic transplants can provide information to make the specific diagnosis of venous thrombosis or occlusion.

An overview of Argentine contributions to diabetes research in the decade of the 1990s

Argentina has a longstanding tradition of diabetes research, beginning with the seminal work of Prof. Bernardo A. Houssay, who was awarded the first Nobel Prize in Medical Sciences for his studies on the relationship between diabetes and pituitary function. Prof. Luis F. Leloir, who was also awarded the Nobel Prize for his work in carbohydrate metabolism, also inspired younger generations of biologists to work in the field of diabetes research. The aim of this paper is to provide a review of the contributions of Argentine researchers during the 1990s. This manuscript includes only reports of Argentine researchers working on diabetes in local laboratories and quoted in Medline. Thus, important contributions not reported in journals included in Medline or produced by Argentine researchers working abroad may have been omitted. The material consists of a brief description of clinical research (epidemiology and costs, metabolic control, associated risk factors, immunological aspects, and other clinical studies) and basic research (animal model with spontaneous diabetes, islet morphology and function in normal and pathological conditions, insulin action, metabolic disorders related to diabetes, and some miscellaneous effects related to drug-induced diabetes). Altogether, a broad idea of the continuous contribution of our national research to the international field of diabetes is provided, as well as a list of Argentine researchers and research centers devoted to the study of diabetes.