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

How to do a spleen preserving porto-splenic pancreas transplantation

Whole organ pancreas transplantation is a validated technique of the management of insulin sensitive diabetes and its complications. While several techniques have been described for this procedure that carries a significant morbidity and small mortality risk, surgery requires adequately sized vessels to implant the organ. In this paper, the authors describe a novel technique of implantation of the pancreas onto the splenic vessels with concomitant splenic preservation or other visceral vessels that they have employed when traditional implantation sites are not suitable with successful outcome on long term follow up.

Salvage of Pancreas Transplant After Successful Splenic Artery Thrombectomy

Primary nonfunction due to thrombosis after pancreas transplant is still the leading cause of nonimmunologic graft failure. Early identification of pancreatic graft arterial thrombus and prompt surgical intervention are effective for rescue of graft perfusion and its associated complications. Here, we report a case of successful surgical thrombectomy of the splenic artery, with particular emphasis on clinical presentation, diagnosis, and surgical technique.

Pancreatic Transplantation: Evaluation and Management

More than 2 million people in the United States have type 1 diabetes mellitus. Pancreatic transplantation has emerged as the single most effective means of achieving normal glucose homeostasis in this patient population. Newer immunosuppressive agents and surgical techniques continue to evolve, resulting in improved long-term graft and patient survival. Herein, an understanding of the evaluation, technical aspects, and perioperative management of pancreas transplantation is outlined.

Multi detector computed tomography (MDCT) for the diagnosis of early complications after pancreas transplantation

PURPOSE

Solitary Pancreas (SPT) and simultaneous kidney-pancreas (SPKT) transplants carry a high risk of surgical complications that may lead to the loss of the pancreas graft and impact later kidney function. The purpose of this study was to investigate the role of MDCT in the diagnosis of early complications and its impact on kidney function.

METHODS

All patients receiving SPT or SPKT over 5 years were retrospectively included. Complications that occurred within the first 15 days were registered and MDCT data analyzed. Data regarding donor, transplant, and recipient characteristics as well as transplantation procedures were analyzed according to the occurrence of early complications. Kidney function at day 3 following MDCT was evaluated.

RESULTS

One hundred and forty-one patients were included (85 men, 56 women; mean age 40.1 years, SD 7.7) with 119 SPKT and 22 SPT. Sixty-four complications were registered in 50 patients. Partial (P-) or complete venous thrombosis (C-VT) occurred in 12.1 % (n = 17), arterial thrombosis (AT) in 1.4 % (n = 2), and hemorrhage in 8.5 % (n = 12) of all patients. For venous thrombosis, the predominant risk factor was body mass index (BMI) for either recipients (P < 0.05) or donors (P < 0.01). Median time for venous thrombosis diagnosis with MDCT was 4 days. Kidney function was not altered following MDCT. Fourteen pancreatectomies were necessary. All patients with C-VT and AT had to undergo graftectomy.

CONCLUSION

Vascular complications occurred early following grafting. Systematic early-enhanced MDCT at day 2-3 should be adequate to detect early thrombosis, especially if risk factors have been identified, without induced kidney function alteration.

Imaging in pancreatic transplants

Pancreatic transplantation, performed alone or in conjunction with kidney transplantation, is an effective treatment for advanced type I diabetes mellitus and select patients with type II diabetes mellitus. Following advancements in surgical technique, postoperative management, and immunosuppression, pancreatic transplantation has significantly improved the length and quality of life for patients suffering from pancreatic dysfunction. While computed tomography (CT) and magnetic resonance imaging (MRI) have more limited utility, ultrasound is the preferred initial imaging modality to evaluate the transplanted pancreas; gray-scale assesses the parenchyma and fluid collections, while Doppler interrogation assesses vascular flow and viability. Ultrasound is also useful to guide percutaneous interventions for the transplanted pancreas. With knowledge of the surgical anatomy and common complications, the abdominal radiologist plays a central role in the perioperative and postoperative evaluation of the transplanted pancreas.

Vascular complications of transplantation: part 2: pancreatic transplants

Vascular complications after solid organ transplantation are not uncommon and may lead to graft dysfunction and ultimately graft loss. A thorough understanding of the surgical anatomy, etiologies, and types of vascular complications, their presentation and the options for management are important for managing these complex patients. This article reviews the basic surgical anatomy, the vascular complications, and endovascular management options of vascular complications in patients with pancreas transplants.

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.

Pancreatic transplant in diabetes

Whole organ pancreas transplantation is increasingly being performed for the treatment of diabetes mellitus. To date, over 32,000 pancreas transplants have been performed worldwide. The procedure is associated with significant mortality and morbidity in early transplant period. However, the successful pancreas transplantation has the potential to render patients insulin-independent and halt the progression of complications of diabetes, thereby improving both quality of life and patient survival.

Imaging of whole-organ pancreas transplants

Whole pancreas transplantation is an established treatment for selected patients with diabetic nephropathy or poorly controlled diabetes. Surgical techniques vary and have evolved over the past 4 decades. Imaging evaluation of the whole-pancreas transplant should begin with an understanding of the most commonly used surgical techniques and the spectrum of postoperative complications. Ultrasonography (US) should be the first-line modality in evaluating the pancreas allograft and vasculature. Computed tomography (CT) is useful in the assessment of extra-allograft processes, particularly in ruling out abscess formation or evaluating suspected bowel complications. Magnetic resonance (MR) imaging is reserved for cases in which complete evaluation with US or CT is not possible. MR angiography can help provide an accurate assessment of vascular abnormalities. The radiologist must be familiar with the spectrum of surgical techniques and the normal postoperative imaging appearances of the whole-pancreas transplant so as to be able to recognize abnormal postoperative findings. Supplemental material available at http://radiographics.rsna.org/lookup/suppl/doi:10.1148/rg.322115144/-/DC1.

Imaging of miscellaneous pancreatic pathology (trauma, transplant, infections, and deposition)

In this article's coverage of miscellaneous pancreatic topics, a brief review of pancreatic trauma; pancreatic transplantation; rare infections, such as tuberculosis; deposition disorders, including fatty replacement and hemochromatosis; cystic fibrosis; and others are discussed with pertinent case examples.

Endovascular management of vascular complications in pancreatic transplants

Vascular complications after pancreatic transplantation carry a high rate of graft loss. Endovascular management of these complications is confined to stent placement for iliac artery inflow disease and embolization for arteriovenous fistulae (AVFs), pseudoaneurysms, or active bleeding. The current study describes the endovascular management of pancreatic transplant venous thrombosis (N = 1), arterial stenosis (N = 5), thrombosis (N = 3), pseudoaneurysms (N = 1), and AVF (N = 2). In addition, embolization of nonfunctioning grafts is described as an endovascular alternative to pancreatectomy.

Complications following pancreatic transplantations: imaging features

Whole organ vascularized pancreatic transplant is a recognized treatment for diabetes and is increasingly being performed worldwide. The procedure itself is complex and is associated with significant mortality and morbidity. Despite improvements in surgical techniques, postoperative complications of pancreatic transplantation are still common and include graft rejection, pancreatitis, peripancreatic fluid collections, exocrine leaks, vascular thrombosis, and hemorrhage. In this pictorial essay, we review clinical presentation and imaging features of these complications. We also briefly discuss technique and complications of islet cell transplants.

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.

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.

Magnetic resonance imaging in pancreas transplantation

Magnetic resonance imaging (MRI) plays an important role in the evaluation of pancreas transplantation. Standard MRI, magnetic resonance angiography, and MR cholangiopancreatography can demonstrate the changes of the anatomy after transplantation. Vascular complications are assessed by MR angiography. Magnetic resonance cholangiopancreatography reveals ductal changes resulting from acute and/or chronic rejection and determines leaks with the use of a secretin-stimulated MR cholangiopancreatography. Serial contrast-enhanced MRI may detect the diminished perfusion that is related to the graft rejection or vascular complications. In this paper, we reviewed types of pancreas transplantation procedures, complications that arise in a short and/or a long term after the transplantation, and their assessment by MRI.

Pancreas allografts: comparison of three-dimensional rotational angiography with standard digital subtraction angiography

PURPOSE

To define the role of three-dimensional (3D) rotational angiography (RA) for the evaluation of pancreas allografts and compare 3D RA to standard digital subtraction angiography (DSA).

MATERIALS AND METHODS

DSA and 3D RA were performed in patients with vascular abnormalities diagnosed on contrast medium-enhanced magnetic resonance (MR) angiography. Patency of the allograft vasculature, confidence in the ability to make a therapeutic decision, and value of the study for definition of the optimal projection for an intervention was assessed on a graded scale.

RESULTS

Seventeen standard DSA projections (mean, 3.4; range, 2-6) and 10 3D RA images (mean, 2; range, 1-3) were obtained in five patients. An average iodinated contrast agent dose of 14.4 mL (range, 8-22 mL) was administered for DSA. An average CO2 dose of 54 mL (range, 0-120 mL) was administered for 3D RA. Five 3D RA procedures were timed for the arterial phase and five were timed for the arterial and venous phases. Average contrast agent doses were 17.6 mL (range, 11-22 mL) for arterial 3D RA and 24.4 mL (range, 16-34 mL) for arterial- and venous-phase 3D RA. Of 68 vascular segments available for direct comparison of patency, complete concordance was present in 96%. There was no difference in the reviewers' diagnostic confidence (10 +/- 0 for both techniques). Three-dimensional RA was considered significantly superior for planning the optimal projection for intervention (10 +/- 0 for 3D RA vs 7.2 +/- 1.6 for DSA; P = .0052).

CONCLUSIONS

Three-dimensional RA of pancreatic allografts is feasible and does not differ in accuracy from conventional DSA. It provides similar reviewer confidence in the ability to make an accurate treatment decision, but its key advantage is its superior ability to define the optimal projection for planned endovascular interventions.

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.

Bowel complications seen on CT after pancreas transplantation with enteric drainage

OBJECTIVE

Bowel-related complications from pancreas transplantation account for much of the postsurgical morbidity. In a review of 98 pancreas transplant recipients, we found 19 (19.4%) with such complications.

CONCLUSION

The most common problems were small-bowel obstruction and anastomotic leaks. Adhesions and internal hernias accounted for most postoperative bowel obstructions.

Contrast-enhanced MR Angiography for Evaluation of Vascular Complications of the Pancreatic Transplant

Vascular complications are a common cause of postoperative dysfunction in a pancreatic transplant. Coronal three-dimensional (3D) contrast material-enhanced magnetic resonance (MR) angiography performed with high spatial and temporal resolution is a safe and effective method of assessing these vascular complications. A study was performed of selected patients who had undergone MR imaging and MR angiography during the past 6 years for evaluation of graft dysfunction following pancreatic transplantation. Thrombosis within peripheral stump vessels involving either the arterial or venous segments was a commonly observed vascular complication. Isolated distal arterial stump thrombi are incidental findings that may not require treatment, whereas venous stump thrombi may become clinically significant in patients in whom clot propagates proximally to occlude draining pancreatic veins and are typically treated with anticoagulants or thrombectomy. Because it is difficult to predict which patients will experience clot propagation, patients with venous stump thrombi may be followed up with serial imaging regardless of treatment initiated at presentation. Although susceptibility artifacts can mimic anastomotic stenoses at MR imaging, careful attention to the multiple sequences used allows recognition of this potential pitfall. Contrast-enhanced 3D MR angiography is an accurate method of evaluating the vascular anatomy of pancreatic transplants and can help guide clinical management.