Activated protein C resistance acquired through liver transplantation

Donor-derived disorders of hemostasis and thrombosis in liver transplantation: Considerations for deceased donor liver selection

OLT is known to be associated with a precarious perioperative hemostatic state due to dysregulation of procoagulant and anticoagulant factors, endothelial injury, and inflammation. Transmission of inherited bleeding and clotting disorders from the liver donor to the recipient may further complicate hemostasis during and after transplantation. As a result, consideration of congenital coagulation disorders in the liver donor is a practical concern for donor selection. However, there is no clear consensus regarding the selection of donors with known or suspected thrombophilia or bleeding disorders. While multiple case reports and retrospective studies, subject to reporting bias, describe donor-derived thrombophilic and bleeding disorders, there are no large-scale studies in the adult liver transplant literature that examine the frequency of transmission, utility of donor screening, or clinical impact of donor hemostatic disorders. Based on the reported literature, we summarize our approach for donor selection with an aim to balance improved organ utility and optimal post-transplant outcomes.

Liver transplantation using grafts with rare metabolic disorders

Metabolic diseases that involve the liver represent a heterogeneous group of disorders. Apart from the metabolic defect, the subject's liver functions may be normal. With the increasing need for organs, livers from donors with metabolic diseases other than familial amyloid polyneuropathy might be possibly used for transplantation. However, whether such livers qualify as grafts and how they might impact recipient outcome are still unanswered questions. This review of the literature summarizes current experience in the use of such grafts in the context of cadaveric, domino, and living-related liver transplantation.

Acquired antithrombin type IIb deficiency after liver transplantation: a case report

A 3-year-old girl with multifocal hepatoblastoma was referred to our clinic for living-donor liver transplantation, the patient's father being the donor. Pretransplant evaluation revealed that the father presented partial asymptomatic antithrombin (AT) deficiency, with no inherited AT deficiency found in the girl. The genetic testing showed an AT type IIb deficiency responsible for a defect in the heparin-binding region of AT which is less thrombogenic but more common than the other AT qualitative defects. Her mother was ABO incompatible. Despite the thrombophilia on the father's side, transplantation was successfully performed under replacement therapy with intravenous AT concentrate and low-molecular-weight heparin thromboprophylaxis given to both the recipient and the donor. No thrombotic complications occurred. In the posttransplantation course, acquired partial AT deficiency was detected in the recipient, who received adjuvant chemotherapy without thrombotic complications. This case report highlights the relevance of full thrombophilic work-up before liver transplantation from a living donor, while illustrating that the procedure can be successfully performed in the case of AT deficiency on the donor's side provided that appropriate AT supplementation and thromboprophylaxis are administered to both the recipient and the donor.

Acquired pseudoxanthoma elasticum presenting after liver transplantation

BACKGROUND

Pseudoxanthoma elasticum (PXE) is thought to be a metabolic disorder resulting from mutations in the gene encoding the cellular transporter, ABCC6, which is primarily expressed in liver and kidney. We encountered 3 patients who developed clinical and histopathological evidence of PXE after liver transplantation, suggesting that PXE could have been acquired from the transplanted organ.

OBJECTIVE

We sought to delineate the clinical features and screen each patient and samples of donor liver for mutations in the ABCC6 gene.

METHODS

Each patient underwent full clinical examination, skin biopsy, and ophthalmologic examination, and whole genome sequencing using standard techniques. Fixed samples of donor liver tissue were available for mutation analysis in two patients and of donor kidney tissue in one.

RESULTS

All 3 patients had unequivocal clinical and histopathologic evidence of PXE. No patient (or family member available for screening) had evidence of mutations in ABCC6. Neither liver specimen nor the single available kidney specimen showed evidence of mutations in ABCC6.

LIMITATIONS

Liver tissue was not available from one patient and DNA was of poor quality in another, resulting in limited screening. Genetic testing does not detect ABCC6 mutations in 10% of patients with confirmed PXE.

CONCLUSION

Although we were unable to demonstrate ABCC6 mutations in limited screening of fixed donor livers, the absence of any PXE mutations in the affected patients, the timing of onset of PXE, and the known acquisition of other metabolic disorders and coagulopathies from donor livers suggest that PXE was likely acquired via liver transplantation.

Management of Hereditary Hypercoagulable Disorders

The clinical management of individuals with hereditary hypercoaguable disorders has evolved from initial broad recommendations of lifelong anticoagulation after first event of venous thromboembolism to a more intricate individualized risk-benefit analysis as studies have begun to delineate the complexity of interactions of acquired and hereditary factors which determine the predilection to thrombosis. The contribution of thrombophilic disorders to risk of thrombotic complications of pregnancy, organ transplantation, central venous catheter and dialysis access placement have been increasingly recognized. The risk of thrombosis must be weighed against risk of long-term anticoagulation in patients with venous thromboembolism. Thrombophilia screening in select populations may enhance outcome.