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.

Islet transplantation offers a minimally-invasive approach for beta cell replacement in diabetic patients with hypoglycemic unawareness. Attempts at insulin independence may require multiple islet re-infusions from distinct donors, thus increasing the risk for allogeneic sensitization. Currently, solid organ pancreas transplant is the only remaining surgical option following failed islet transplantation in the US. However, the immunologic impact of repeated exposure to donor antigens on subsequent pancreas transplantation is unclear. Here we describe a case series of seven patients undergoing solid organ pancreas transplant following islet graft failure, with long-term follow-up of pancreatic graft survival and renal function. Despite highly variable panel-reactive antibody (PRA) levels prior to pancreas transplant (mean 27±35%), all seven patients achieved stable and durable insulin independence with a mean follow-up of 6.7 years. Mean hemoglobin A1c (HgbA1c) values improved significantly from post-islet, pre-pancreas levels (mean 8.1±1.5%) to post-pancreas levels (mean 5.3±0.1%; p=0.0022). Three patients experienced acute rejection episodes successfully managed with thymoglobulin and methylprednisolone, and none of these pre-uremic type 1 diabetic recipients developed Stage 4 or 5 chronic kidney disease postoperatively. These results support pancreas-after-islet (PAI) transplantation with aggressive immunosuppression and protocol biopsies as a viable strategy to restore insulin independence after islet graft failure.

Background. Stopping immunosuppression in a transplant patient with donor-derived malignancy offers the theoretical benefit that reconstitution of the patient’s immune system will allow “rejection” of the malignancy, as the malignancy also originates from allogeneic tissue. However, this option exists with the caveat that the patient’s allograft(s) will likely be rejected too. In simultaneous pancreas-kidney (SPK) recipients, the normal continued functioning and possible absence of malignancy in either the unaffected kidney or pancreas further complicate this decision. Methods. The charts of 3 patients with donor-derived metastatic malignancies after SPK were retrospectively reviewed in detail. We provide treatment and management recommendations based on successful outcomes and a review of the existing literature. Results. Consistent with a broad review of the literature, in all 3 cases, complete immunosuppression cessation, removal of both grafts, and in 1 case treatment with an immune checkpoint inhibitor to augment the immune response was successful. One patient is doing well 1 year after successfully undergoing kidney retransplantation, while a second patient is active on the waitlist for SPK retransplantation after no evidence of metastatic disease for 2 years. Conclusion. The successful management of metastatic donor-derived malignancies requires allograft removal, immunosuppression cessation, and adjuvant therapy that includes occasional use of checkpoint inhibitors to augment the immune response.

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