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Vanessa H de Villa

Publications and source records attributed to Vanessa H de Villa.

8 recordsLinked to original sources

Ethics and rationale of living-donor liver transplantation in Asia.

Living-donor liver transplantation took root in Asia as a natural result of circumstances, because the supply of organs from the cadaveric pool remained scarce over the years. In contrast to Western countries, the majority of organs for liver transplantation in Asia come from live donations. As the expertise of the transplant teams grows, patient outcomes improve, and public awareness increases, the option of live donation of the liver is increasingly chosen. Although no live liver donor death has yet been reported from Asia, the risk is not eliminated and remains a major consideration in the potential donor's decision to donate. The low morbidity and mortality rate could be attributed to the extensive experience of surgeons in liver surgery, because surgical liver disease is highly prevalent in Asia. Although the donor risk is estimated to be low, live organ donation should be absolutely voluntary, with consent given on the basis of unbiased information and chosen only when the option for obtaining a cadaveric graft is practically nil. It is only under these conditions that living-donor liver transplantation should be perpetuated. Although the disease-donation-transplantation process involves a complex interplay of psychosocial and family dynamics, the potential candidate's perception will necessarily depend on the surgeon's explanation. The ethical soundness of the practice of living-donor liver transplantation rests primarily on the ones who deliver the service.

Asia↗

Hepatitis B core antibody-positive grafts: recipient's risk.

The transmission of hepatitis B virus infection through hepatitis B core antibody (anti-HBc)-positive liver grafts in hepatitis B surface antigen (HBsAg)-negative recipients has been established. The mandatory use of immunosuppression in transplant patients favors reactivation of latent virus that may be present in grafts from HBsAg-negative anti-HBc-positive donors. With the persistent organ donor scarcity, the use of these grafts cannot be avoided, especially in urgent cases and in areas where the prevalence of the hepatitis B virus is high, as in Asia. The recognition of posttransplant de novo hepatitis B from core antibody-positive liver donors has, therefore, led to modifications in graft allocation policies and the introduction of strategies for prophylaxis. The risk of developing this type of new-onset hepatitis B virus infection in liver transplant recipients and the various approaches to minimize this risk are reviewed. The peculiar implications of using core antibody-positive grafts in the context of living donor liver transplantation in Asia are discussed.

Hepatitis B↗

Stress response to hepatectomy in patients with a healthy or a diseased liver.

Partial hepatectomy is a major upper abdominal operation associated with certain stress to the patient. Successful adaptation to such stress is a prerequisite for survival. Donor hepatectomy with maximal safety is a principal concern during living donor liver transplantation. The purpose of the study was to compare the stress response by assessing cytokines and the acute-phase response induced by hepatectomy in patients with a healthy liver and those with a diseased liver. Fourteen patients undergoing partial right hepatectomy were enrolled in this study. Seven of them were donors for living related liver transplantation (group 1, or GI); the other seven were patients with hepatocellular carcinoma due to chronic hepatitis B (Child's class A) (GII). Blood samples for interleukin-6 (IL-6), tumor necrosis factor-alpha (TNFalpha), and C-reactive protein (CRP) assays were collected before the operation, at the beginning and end of the operation, and 24 and 48 hours after the operation. The data were analyzed and compared in the same group using the Friedman test and between groups using the Mann-Whitney U-test. A value of p < 0.05 was regarded as significant. Results showed that resection of the liver in patients with both healthy and disease livers leads to significant increases in IL-6 and CPR but not TNFalpha. Significantly lower levels of IL-6 before and after operation in GI patients compared to those in GII patients suggests that GI patients adapted to surgical stress more easily than did the GII patients.

Adaptation, Physiological↗

Right lobe living donor liver transplantation-addressing the middle hepatic vein controversy.

OBJECTIVE: To describe our approach in the decision-making for taking the middle hepatic vein with the graft or leaving it with the remnant liver in right lobe live donor liver transplantation. SUMMARY BACKGROUND DATA: Right lobe living donor liver transplantation has been successfully performed. However, the extent of donor hepatectomy is still a subject of debate and the main considerations in the decision making are graft functional adequacy and donor safety. METHODS: An algorithm based on donor-recipient body weight ratio, right lobe-to-recipient standard liver volume estimate, and donor hepatic venous anatomy was used to decide the extent of donor hepatectomy. This algorithm was applied in 25 living donor liver transplant operations performed between January 1999 and January 2002. In grafts taken without the middle hepatic vein, anterior segment tributaries draining into it were not reconstructed. Outcomes between right lobe liver transplants with (Group I) and without (Group II) the middle hepatic vein were compared. RESULTS: Ten grafts included the middle hepatic vein and 15 did not. The mean graft to recipient standard liver volume ratio was 58% and 64% in Groups I and II, respectively, and the difference was not statistically significant. Donors from both groups had comparable recovery, with 2 complications, 1 from each group, requiring a percutaneous drainage procedure. The recipient outcomes were, likewise, comparable and there was 1 case of structural outflow obstruction in Group I, which required venoangioplasty and stenting. There were 2 recipient mortalities, 1 due to a biliary complication and the other to recurrent hepatitis C. Another patient required retransplantation for secondary biliary cirrhosis. The overall actuarial graft and patient survival rates are 84% and 96%, respectively, at a median follow-up of 16 months. CONCLUSION: Based on certain preoperative criteria, a right lobe graft can be taken with or without the middle hepatic vein with equally successful outcomes in both the donors and recipients. The decision, therefore, of the extent of right lobe donor hepatectomy should be tailored to the particular conditions of each case.

Adult↗

Split liver transplantation.

Greater experience and improved outcomes in liver transplantation have necessarily led to longer waiting lists against a constantly limited donor pool. Split liver transplantation has been conceived as a means to increase the supply of liver grafts. The bipartition of a whole liver provides grafts for two recipients in a complex operation with equally complex manpower and logistical demands. The in situ technique of splitting offers advantages over the ex vivo technique, although after the time-dependent learning curve is overcome, they may theoretically be used interchangeably with acceptable outcomes. Aside from surgical expertise, donor characteristics and recipient pre-transplant status are risk factors for survival. This review will address the salient aspects of split liver transplantation, summarize the world experience with this procedure and describe the preliminary attempts in Asia.

Adult↗

Prevention of de novo hepatitis B virus infection in living donor liver transplantation using hepatitis B core antibody positive donors.

Exclusion of liver grafts from hepatitis B core antibody (anti-HBc) positive donors to prevent de novo hepatitis B virus (HBV) infection after liver transplantation is not feasible in areas highly endemic for HBV virus like Taiwan, where approximately 80% of adults are anti-HBc(+). The efficacy of lamivudine monotherapy to prevent de novo HBV infection after living donor liver transplantation (LDLT) using grafts from anti-HBc(+) donors remains to be elucidated. From June 1994 to August 2000, LDLT was performed in 42 recipients. Twenty-four of the 42 donors were anti-HBc(+) (57%). Pre-transplant HBV vaccination was given to all recipients irrespective of anti-HBc status at monthly intervals for 3 months. Until December 1997, eight recipients received liver grafts from anti-HBc(+) donors without prophylaxis. Since January 1998, prophylaxis with lamivudine monotherapy was given to 16 recipients receiving liver grafts from anti-HBc(+) donors. De novo HBV infection occurred in three of the eight recipients (37.5%) who did not receive prophylaxis, while none of the 16 recipients given lamivudine developed de novo HBV infection after a mean follow-up of 25 months. Two of the three recipients with de novo HBV infection were anti-HBs(-) and one recipient was anti-HBs(+). Lamivudine was well tolerated, and no side effects were noted. These results suggest that lamivudine monotherapy for recipients receiving anti-HBc(+) liver grafts is a simple, relatively inexpensive and effective prophylactic regimen for prevention of de novo HBV infection. The additive protection provided by vaccine-induced or natural immunity is uncertain.

Adolescent↗

The effect of hypernatremia on liver allografts in rats.

UNLABELLED: Hypernatremia in the donor organ is one of the most dangerous risk factors that may cause primary graft loss after orthotopic liver transplantation (OLT). However, the viability of donor grafts from acute hypernatremic donors, which is likely to occur during resuscitation of trauma patients with hypertonic saline solution, has not been studied precisely. In the present study, we sought to evaluate whether the hypernatremia, per se, induced by hypertonic saline solution, affects the outcome of liver transplantation in the normal rat. Thirty minutes after the induction of hypernatremia (>160 mEq/L), the livers of nine Wistar rats were removed under ether anesthesia. Six livers were immediately transplanted into normal Wistar rats, whereas the other three were preserved in 4 degrees C University of Wisconsin solution for 6 h before transplantation in the recipients. Liver function variables of the donor rats at graft procurement and of the recipients at Day 7 after OLT were compared with a control group. The water content of the graft at procurement and the survival of the recipients at 7 days after OLT were, likewise, compared with the untreated control group. Results showed that there were no significant differences in the liver function tests of the donors and recipients, as well as in the water content of the grafts, between groups. All the rats survived the observation period of 7 days. This study showed that acute hypernatremia induced by the infusion of 10% saline solution before graft procurement in a nonbrain-dead donor rat model did not lead to a deterioration of liver graft viability after OLT. IMPLICATIONS: Hypernatremia in cadaveric donors may be detrimental to the graft in clinical liver transplantation, but acute donor hypernatremia induced by an IV infusion of 10% saline solution before graft procurement in nonbrain-dead rats did not affect the survival of the recipient rats in an experimental liver transplantation model.

Animals↗

Characterization of liver enzymes on living related liver transplantation patients with acute rejection.

BACKGROUND/AIMS: To determine the biochemical data that reliably predict allograft injury from acute rejection (AR) in patients with living related liver transplantation (LRLT), liver function test and histopathological characteristics of AR were compared and analyzed retrospectively. METHODOLOGY: From Aug. 1994 to Nov. 2000, 101 cases received orthotopic liver transplantation (OLT), which included 53 patients with LRLT in our series. Completed liver functions including aspartate transferase (AST), alanine transferase (ALT), bilirubin total/direct (Bil.T/D), alkaline phosphatase (ALP) and gamma glutamyl transpeptidase (GGT) were collected with peak level when AR was diagnosed by liver biopsy. The best data of the same patients when disease free, were compared and analyzed with non-parametric Wilcoxon signed ranks test and Mann-Whitney test. All of the ARs were reversed with steroid pulse therapy, and two cases converted to FK506. No steroid-resistant rejection or chronic rejection was found in our series. RESULTS: In the patients with LRLT, 17 episodes in 13 patients with AR were found. The incidence of histological analysis proved AR was 12.9% (13/101) in OLT and 24.5% (13/53) in LRLT respectively. Among the liver function tests, AST (p<0.0001), ALT (p<0.0001), Bil.T (p=0.001), Bil.D (p=0.001), GGT (p<0.0001), and INR (p=0.034) were the significant predictors respectively in the patients with AR episode. Once liver enzymes had elevated, the AST/ALT ratio <1.0 showed a more significant difference in AR than in those of the no rejection group (p<0.0001). ALP showed significant difference in our series. The severity of histological change was not correlated to the degree of liver enzymes elevation. CONCLUSIONS: Complete liver function tests especially AST, ALT, Bil.T/D, GGT and the ratio of AST/ALT are very sensitive tests in a group of patients receiving LRLT with AR. The severity of AR is based on the histopathologic change but is not related to the degree of liver enzymes elevation itself. Meanwhile, the outcome of acute rejection in living related liver transplantation is quite good.

Acute Disease↗