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Bioethics of living donor liver transplantation

Bioethics of living donor liver transplantation

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並列摘要


Bioethics has been central to living donor liver transplantation (LDLT), which mandates a high recipient benefit and an acceptably low donor risk. The double equipoise imposes the contextual features of this already technically complex treatment. This research aimed at looking into key bioethical issues of LDLT in the light of the contemporary practice standards. In adult LDLT, in order to provide a partial graft of adequate size, donor right hepatectomy is often required. This procedure pioneered by The University of Hong Kong is now being performed at many centers and by many surgeons. Through close guidance and gradual granting of surgical privilege, newer surgeons can now perform this operation safely with low blood loss (400 mL) and low complication rates ( 30%). Analysis of our series also showed that right liver donors with a smaller remnant left liver had higher peak bilirubin level and longer peak prothrombin time after the operation. Severe complications were associated with hyperbilirubinemia (p=0.031) while prolonged hospital stay was associated with prolonged prothrombin time (p=0.011) and smaller remnant left liver (p=0.036). Facts need to be known to potential right liver donors before operation. Donor left hepatectomy, which carries a lower donor risk, is more feasible for donors with a larger left liver and recipients with a smaller body size. Lowering the graft size requirement also allows more LDLTs being done using left livers. The percentages of left liver LDLTs feasible with a graft to standard liver volume (G/SLV) ≥ 40%, ≥ 35%, ≥ 30%, and ≥ 25% were 5.8%, 12.5%, 29.1%, and 62.3% respectively. For every 5% decrease in G/SLV ratio, twice as many left liver LDLTs could be performed. The 5-year survival rate was 85.7% for liver transplantation recipients with hepatocellular carcinoma (HCC) within the Up-to-7 criteria, unaffected by the presence of microvascular invasion (88.2% vs. 85.1%, p=0.652). This is comparable with that of liver resection patients with HCC without microvascular invasion (81.2%, p=0.227) but far superior to that of liver resection patients with lesions with microvascular invasion (50.0%, p<0.0001). Primary liver transplantation for HCC with microvascular invasion and within the Up-to-7 criteria in fact doubled the chance of cure as compared with liver resection. LDLT has been criticized of fast-tracking patients with more aggressive HCC for transplant. Waiting does select out patients with better survival to undergo transplantation. With careful selection though without waiting, LDLT nevertheless does not confer poorer survival. Progressive liver failure following a major hepatectomy for HCC is a known and uncommon cause of mortality. Proceeding to LDLT is an ethical challenge because of the possibility of coercion. Tumor status as confirmed by histopathological examination of resected specimens can demonstrate features of more aggressive cancer, which warns against a rescue transplantation for the increase in chance of tumor recurrence. In order to overcome ABO blood group incompatibility, paired donor interchange (between two pairs: A to B and B to A) has been practiced for the liver. The extension to matching with one pair of universal donor (O) and universal recipient (AB) was also performed at our center. The obvious biological advantage of this treatment modality has to be weighed against the potential increase in risks to patients involved. Media coverage of advances and successes in liver transplantation stimulates deceased donor organ donation (DDOD). The relation between widely reported key events and DDOD can be recognized as celebrity hero influence, medical success, or emotional response. An accountable liver transplant service answerable to the public is vital to a region where the DDOD rate is low. Selective disclosure of patient information to the media for public interest in promoting organ donation can be justified. LDLT now has a two-decade history of clinical practice. Basic and clinical research has provided a clearer picture of the efficacy and fallibility of LDLT. We can now be more accurate in defining and interpreting the applicability of LDLT for a wider spectrum of disease indications.