Arterial reconstruction in hepatic and pancreatic allograft transplantation following multi-organ procurement

Investigation of a method for long-term preservation of the vascular allograft

BACKGROUND/OBJECTIVE

During multiple organ procurement, blood vessels are routinely retrieved and stored in University of Wisconsin solution and then discarded after two weeks, if not used at organ transplantation owing to lack of a method for long-term preservation. Therefore, the aim of this study is to investigate a method for long-term preservation of vascular allografts in ethanol.

METHODS

Aorta and vena cava allografts were retrieved and stored in 75% ethanol solution for 12 months at 4°C. Four pigs were divided into two groups. A segment of aorta was excised and replaced by insertion of preserved aorta graft (Group A) or vena cava graft (Group V). The pigs were observed for six weeks. A laparotomy was performed and the vascular graft was harvested for histopathology followed by euthanasia at the end of study.

RESULTS

Three pigs recovered uneventfully, while one pig died from venous graft rupture in the third week after surgery. There was no aneurysmal formation or thrombosis in the grafts. Some calcification was seen over aorta allograft. On histopathology, the elastic pattern was almost normal, although the endothelial cells degenerated after preservation. After implantation, the formation of the endothelium cell-like layer was seen in both aorta and vena cava allografts.

CONCLUSION

Vascular allografts were functional after preservation for 12 months. The vena cava grafts had much less wall calcification than the aorta grafts. Further studies are necessary to investigate vascular graft remodelling with a longer observation period after implantation.

Personal experience with the procurement of 32 liver allografts

AIM: To introduce the American Pittsburgh’s method of rapid liver procurement under the condition of brain death and factors influencing the quality of donor liver.

METHODS: To analyze 32 cases of allograft liver procurement retrospectively and observe the clinical outcome of orthotopic liver transplantation.

RESULTS: Average age of donors was 38.24 ± 12.78 years, with a male:female ratio of 23:9. The causes of brain death included 21 cases of trauma (65.63%) and nine cases of cerebrovascular accident (28.13%). Fourteen grafts (43.75%) had hepatic arterial anomalies, seven cases only right hepatic arterial anomalies (21.88%), five cases only left hepatic arterial anomalies (15.63%) and two cases of both right and left hepatic arterial anomalies (6.25%) among them. Eight cases (57.14%) of hepatic arterial anomalies required arterial reconstruction prior to transplantation. Of the 32 grafts evaluated for early function, 27 (84.38%) functioned well, whereas three (9.38%) functioned poorly and two (6.25%) failed to function at all. Only one recipient died after transplantation and thirty-one recipients recovered. Four recipients needed retransplantation. The variables associated with less than optimal function of the graft consisted of donor age (35.6 ± 12.9 years vs 54.1 ± 4.3 years, P < 0.05), duration of donor’s stay in the intensive care unit (ICU) (3.5 ± 2.4 d vs 7.4 ± 2.1 d, P < 0.005), abnormal graft appearance (19.0% vs 100%, P < 0.05), and such recipient problems as vascular thromboses during or immediately following transplantation (89.3% vs 50.0%, P < 0.005).

CONCLUSION: During liver procurement, complete heparization, perfusion in situ with localized low temperature and standard technique procedures are the basis ensuring the quality of the graft. The hepatic arterial anomalies should be taken care of to avoid injury. The donor age, duration of donor’s staying in ICU, abnormal graft appearance and recipient problem are important factors influencing the quality of the liver graft.

Microsurgical reconstruction of hepatic artery during living donor liver transplantation

Living donor liver transplantation (LDLT) has become a well-recognized treatment modality for patients with end-stage liver disease. Arterial reconstruction during LDLT is perhaps the most important aspect of the grafting procedure. Although microsurgical hepatic artery reconstruction has become the essential technique in LDLT, it poses significant challenges even to experienced microsurgeons. In this report, the experiences of 155 microsurgical reconstructions of the hepatic artery in 150 LDLTs were reviewed, and the problems that were encountered and the solutions are discussed. From June 1999-March 2004 150 LDLTs were performed on 148 recipients at Ege University Organ Transplantation and Research Center. Hepatic arterial thrombosis was encountered in 3 patients. Microsurgical technique has overcome the difficulties in LDLT. This has increased liver transplantations in the presence of limited cadaver grafts and has decreased the patient mortality in the waiting list.

A single center's clinical experience with quadruple immunosuppression including ATG or IL2 antibodies and mycophenolate mofetil in simultaneous pancreas-kidney transplants

Acute rejection remains a major problem in simultaneous pancreas-kidney (SPK) transplant and occurs in 60-100% of the cases. With the introduction of mycophenolate mofetil (MMF) replacing azathioprine (AZA) as a basis immunosuppressant, reduced rates of rejection have been reported. This study investigates the frequency and clinical relevance of allograft rejection in SPK patients receiving antithymocyte globulin (ATG) or Basiliximab induction therapy and cyclosporine Neoral (CyA), MMF, steroid basis immunosuppression. Between December 1996 and October 1999, 21 consecutive patients (15 males, 6 females) received a SPK transplant at our institution with a mean +/- standard deviation (SD) age of 42 +/- 6 yr. Of these, 14 patients were treated with anti-thymocyte globulin (ATG) Fresenius (rabbit) 3-5 mg/kg for 6 +/- 2 d, cyclosporine Neoral (CyA) (trough levels 350-400 ng/mL), MMF 3 g/d and low dose steroid therapy. Seven SPK patients were treated with Basiliximab (Simulect, Novartis 20 mg on d 0 and d 4 post-transplant) instead of ATG. The patients had an average human leucocyte antigen (HLA) mismatch of 3.9/6 and a negative cross match. All patients remained on triple drug therapy. Three patients were switched to tacrolimus instead of Neoral for CyA intolerance. The mean +/- SD cold ischemia time (CIT) of the organs was 10.1 +/- 2.4 h for the pancreas and 10.5 +/- 2.6 h for the kidney.

RESULTS

Biopsy-proven rejection occurred in the kidney of 1 ATG patient (8%), which responded to steroid bolus therapy. One of the patients (14%) with Basiliximab induction developed renal allograft rejection, which was resolved after a 6-d course of anti-CD3 mAb (OKT3) treatment. All patients (100%) were free from rejection in the pancreas, as measured by urine amylase levels and glycemic control without the need for exogenous insulin with a mean glycosylated hemoglobin (HBA1C) of 5.1 +/- 0.7%, and serum creatinine with a mean of 1.24 +/- 0.24 mg/dL in a mean follow-up period of 17 +/- 15 months (median 12, range 2 37).

CONCLUSION

Triple drug immunosuppression including cyclosporine, MMF and low dose steroids with ATG or interleukin 2 (IL2) receptor antibodies induction therapy appears to be a very suitable immunosuppressive regimen for combined pancreas-kidney transplant (PKT) with a marked reduction in the incidence of rejection.