Percutaneous transcatheter thrombolysis for graft thrombosis after pancreas transplantation

Salvage Endovascular Thrombectomy for Splenic Vein Thrombosis After Pancreas Transplantation: A Single-Center Experience and Systematic Literature Review

OBJECTIVES

Technical graft loss, usually thrombotic in nature, accounts for most of the pancreas grafts that are removed early after transplant. Although arterial and venous thrombosis can occur, the vein is predominantly affected, with estimated overall rate of thrombosis of 6% to 33%. In late diagnosis, the graft will need to be removed because thrombectomy will not restore its functionality. However, in early diagnosis, a salvage procedure should be attempted.

MATERIALS AND METHODS

We conducted a retrospective, descriptive analysis of a prospective database of patients who underwent pancreas transplant from April 2008 to June 2020 at a single center. We evaluated post-transplant clinical glucose levels, imaging, treatment, and outcomes. We also performed a systematic review of publications for endovascular treatment of vascular graft thrombosis in pancreas transplant.

RESULTS

In 67 pancreas transplants analyzed, 13 (19%) were diagnosed with venous thrombus. In 7 of 13 patients (54%), systemic anticoagulation was prescribed because of a non-occlusive thromboses, resulting in complete resolution for all 7 patients. Six patients (46%) required endovascular thrombectomy because of the presence of complete occlusive thrombosis; 4 of these patients (67%) needed a second procedure because of recurrence of the thrombosis. One of the 6 patients (17%) required a surgical approach, resulting in successful removal of the recurrent clot. Twelve of the 13 grafts (92%) were rescued. Graft survival at 1 year was 84%; graft survival at 3, 5, and 10 years remained at 70%.

CONCLUSIONS

Pancreas vein thrombosis represents a frequent surgical complication and remains as a challenging problem. In our experience, early diagnoses and an endovascular approach combined with aggressive medical treatment and follow-up can be used for successful treatment and reduce graft loss.

Current state of pancreas transplantation in Japan based on the nationwide registry

In Japan, 437 pancreas transplantations (PTx) were carried out between 2000 and 2019. Clinical data for all PTx cases are registered in the Japan Pancreas Transplant Registry of the Japan Society for Pancreas and Islet Transplantation. Here we analyzed the registry data to describe the current status of PTx in Japan. The 437 PTx included 410 from deceased donors (407 from brain-dead and 3 from non-heart-beating donors) and 27 from living donors. We investigated the clinical characteristics of the 410 PTx from deceased donors. The rate of marginal donors using expanded donor criteria was higher in Japan than in other countries. At 1/5/10 years post-PTx, the overall survival rates were 95.8%/94.2%/88.7%, and the graft survival rates were 85.9%/76.2%/67.4% for pancreas and 93.2%/90.8%/78.2% for kidney (non-censored for death). These rates were comparable to those in other countries. When stratified by PTx category, survival was significantly better following simultaneous pancreas-kidney transplantation (SPK) compared to pancreas-after-kidney transplantation (PAK) or PTx alone (PTA). Immunological rejection was more frequently the cause of graft loss in PAK/PTA cases than in SPK cases, potentially contributing to the poorer survival in PAK/PTA. These outcomes highlight two main concerns: substantial incidence of pancreas graft loss, and inferior outcomes after PAK/PTA. Overall, PTx outcome is favorable in Japan, despite the high rate of marginal donors. To improve outcomes, it is important to prevent and manage each cause of pancreas graft loss. Overcoming the poorer survival in PAK/PTA may require new immunosuppressive protocols or allogenic islet transplantation.

Distal allograft pancreatectomy for graft salvage after pancreas transplantation

Early pancreas allograft failure most commonly results from vascular thrombosis. Immediate surgical intervention may permit pancreas allograft salvage, typically requiring thrombectomy. In cases of partial allograft necrosis secondary to splenic arterial thrombosis, distal allograft pancreatectomy may allow salvage of at least half of the pancreas allograft with retention of function. We retrospectively reviewed four cases of simultaneous pancreas and kidney recipients who required distal allograft pancreatectomy for splenic artery thrombosis with necrosis of the distal pancreas. Three of the four maintained long-term allograft function with euglycemia independent of insulin at six months to six years of follow-up, and all patients continue to maintain normal renal allograft function. Early diagnosis and early intervention are essential in order to salvage the pancreas allograft in the case of thrombosis. Distal allograft pancreatectomy can be performed safely and result in excellent long-term outcomes in select patients.

Management of vascular and nonvascular complications following pancreas transplantation with interventional radiology

Pancreas transplantation exposes to high rates of complications, either vascular (thrombosis, stenosis, pseudoaneurysm, arteriovenous fistula) or nonvascular (fluid collection, graft rejection). With advances in percutaneous and endovascular techniques, interventional radiologists are increasingly involved in the management of these complications. In this article, we review the anatomical considerations relevant to pancreas transplantation, the techniques used for image-guided interventions for vascular and nonvascular complications, and the expected outcomes of these interventions.

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.

Splenic Vein Thrombosis Following Pancreas Transplantation: Identification of Factors That Support Conservative Management

Prophylaxis for graft portal/splenic venous thrombosis following pancreas transplant varies between institutions. Similarly, treatment of venous thrombosis ranges from early re-exploration to conservative management with anticoagulation. We wished to determine the prevalence of graft splenic vein (SV) thrombosis, as well as the clinical significance of non-occlusive thrombus observed on routine imaging. Records of 112 pancreas transplant recipients over a 5-year period at a single center were reviewed. Venous thrombosis was defined as absence of flow or presence of thrombus identified in any part of the graft SV on ultrasound. Thirty patients (27%) had some degree of thrombus or absence of flow in the SV on postoperative ultrasound. There were 5 graft losses in this group. Four were due to venous thrombosis, and occurred within 20 days of transplant. All patients with non-occlusive partial SV thrombus but normal arterial signal on Doppler ultrasound were successfully treated with IV heparin followed by warfarin for 3-6 months, and remained insulin independent. Findings of arterial signal abnormalities, such as absence or reversal of diastolic flow within the graft, require urgent operative intervention since this finding can be associated with more extensive thrombus that may lead to graft loss.

Endovascular Stenting of Portal Vein for Graft Rescue after a Pancreas Transplant Venous Graft Thrombosis: A Case Report

Venous thrombosis of pancreas transplant allografts often leads to graft loss. It is an worrisome complication and difficult to treat, forming the most common nonimmunological cause of graft loss. Multiple risk factors have been implicated in the development of venous thrombosis of pancreas transplant. Color Doppler ultrasonography enables early diagnosis of venous thrombosis, thus increasing the possibility of graft-rescue treatments. Endovascular management of pancreatic transplant vascular complications is scant and in the form of case reports. We report a case of early detection of pancreatic graft venous thrombosis that was treated successfully by catheter-directed thrombolysis mechanical thrombectomy, percutaneous transluminal angioplasty, and stenting of portal vein.

Clinical Experience with Pancreas Graft Rescue From Severe Thrombus After Simultaneous Pancreas-Kidney Transplantation by Early Detection with Doppler Ultrasound: A Case Report

Patient: Female, 41

Final Diagnosis: Graft thrombosis

Symptoms: None

Medication: —

Clinical Procedure: Doppler ultrasound

Specialty: Transplantology

Endovascular Management for the Treatment of Pancreas Transplant Venous Thrombosis: A Single-Center Experience

PURPOSE

To investigate the safety and efficacy of mechanical thrombectomy used as a tool for graft rescue in patients with pancreas graft venous thrombosis (PGVT).

MATERIALS AND METHODS

Graft venous thrombosis was discovered in 36 (33%) of 110 patients who underwent pancreas transplantation. Percutaneous aspiration thrombectomy was performed in seven patients (mean age, 31 y; range, 15-36 y) who had complete or severe thrombosis of the splenic vein or superior mesenteric vein seen on postoperative computed tomography.

RESULTS

Successful evacuation of PGVT was possible in six of seven patients; the thrombus was partially evacuated in one patient. In this patient, subsequent anticoagulation salvaged the graft, rendering primary and secondary technical success rates as 86% and 100%, respectively. As pancreas grafts were successfully functioning in all seven patients within 1 month after endovascular treatment, the clinical success rate was 100%. There were no procedure-related complications. At the last follow-up evaluation, all seven patients were alive with no graft loss (mean follow-up time, 9.4 mo; range, 3.6-22.2 mo).

CONCLUSIONS

Endovascular treatment may be considered in patients with severe PGVT to prevent early graft loss.

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.

Pancreas transplants venous graft thrombosis: endovascular thrombolysis for graft rescue

PURPOSE

To retrospectively assess the efficacy and safety of percutaneous endovascular treatment in patients with pancreas venous graft thrombosis (PVGT).

MATERIALS AND METHODS

Between 2001 and 2009, 206 pancreas transplants were performed at our institution. A retrospective review of pancreas graft recipients who underwent endovascular therapy for PVGT was performed. The study group included 17 patients (10 men, 7 women; mean age 38 years) with PVGT (<60 % [9 patients]; 30-60 % [8 patients]) 6.6 ± 5.7 days after grafting. The angiographic studies, type of endovascular procedure, endovascular procedural and postprocedural effectiveness, and patient and graft outcomes were assessed.

RESULTS

In 16 of 17 cases (94 %), significant (87.5 %) or partial (12.5 %) lysis of thrombi was achieved. One patient had external compression of the portal vein due to a hematoma, which hindered mechanical removal of the thrombi. This patient required graft pancreatectomy for extensive areas of parenchymal necrosis 2 days after the endovascular procedure. No complications related to endovascular treatment were observed. Postprocedural bleeding episodes related to anticoagulation were observed in five patients. Patient and pancreas graft survival rates at 12 months were 94 and 76 %, respectively.

CONCLUSION

Catheter-directed thrombectomy is an effective treatment for patients with PVGT. Percutaneous thrombectomy, followed by anticoagulation, appears to be an effective therapy to remove the thrombus and is associated with a low complication rate.

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.

Prevention and management of graft thrombosis in pancreatic transplant

Pancreatic transplant effectively cures type 1 diabetes mellitus and maintains consistent long-term euglycemia. However, technical failure, and in particular graft thrombosis, accounts for the vast majority of transplants lost in the early postoperative period. The pancreas' inherently low microvascular flow state makes it vulnerable to vascular complications, as does the hypercoagulable blood of diabetic patients. Ultimately, the phenomenon is most definitely multifactorial. Prevention, as opposed to treatment, is key and should focus on reducing these multiple risk factors. This will involve tactical donor selection, optimal surgical technique and some form of anticoagulation. Close monitoring and early intervention will be crucial when treating thrombosis once preventative methods have failed. This may be achieved by further anticoagulation, graft salvage, or pancreatectomy with retransplant. This article will explore the multiple factors contributing to graft thrombus formation and the ways in which they may be addressed to firstly prevent, or more likely, reduce thrombosis. Secondly, we will consider the management strategies which can be implemented once thrombosis has occurred.

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.

Current status of organ transplantation in Japan and worldwide

Recent advances in immunosuppressant therapy have dramatically reduced the frequency of acute rejection of organ transplants. Subsequently, the short-term graft survival rate has been improved, and ABO blood type-incompatible and existing anti-HLA antibody-positive kidney transplantation has been enabled, which has increased the availability of living kidney donors. Japan has a unique history and strategies of liver transplantation (LT) for various liver diseases. The outcomes of living donor liver transplantation (LDLT) in Japan is comparable to that of deceased donor liver transplantation (DDLT) in Western countries despite the relatively short history of LT. The main disadvantage of LT in Japan is donor shortage mainly due to the small number of available deceased donors. There are some disadvantages with LDLT in autoimmune liver diseases because of the dependence on blood relative donors. The first brain-dead pancreas transplantation (PTx) was performed in 2000. Since that time, 42 brain-dead PTx, 2 non-heart beating PTx, and 14 living donor PTx had been performed by the end of 2007. One of the 44 recipients of deceased donor PTx died of unknown causes 11 months after transplantation. Although most of the deceased donors in Japan were marginal and their condition was not favorable, the results of these cases were comparable to those of Western countries. Fourteen intestinal transplantations (ITx) had been performed by the end of 2007 in four transplant centers. There were 3 deceased donor and 11 live donor transplants. The original diseases included short bowel syndrome (n = 6), intestinal function disorder (n = 6), and retransplantation (n = 2). The graft and patient survival rate are 60% and 69%, respectively. Eight recipients survived and stopped parenteral nutrition with full-functioning grafts. Amendment of the Japanese law for the utilization of deceased donors should increase the number available donors in the future.

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.