Dualistic role of platelets in living donor liver transplantation: Are they harmful?

Platelets are anucleate fragments mainly involved in hemostasis and thrombosis, and there is emerging evidence that platelets have other nonhemostatic potentials in inflammation, angiogenesis, regeneration and ischemia/reperfusion injury (I/R injury), which are involved in the physiological and pathological processes during living donor liver transplantation (LDLT). LDLT is sometimes associated with impaired regeneration and severe I/R injury, leading to postoperative complications and decreased patient survival. Recent studies have suggested that perioperative thrombocytopenia is associated with poor graft regeneration and postoperative morbidity in the short and long term after LDLT. Although it is not fully understood whether thrombocytopenia is the cause or result, increasing platelet counts are frequently suggested to improve posttransplant outcomes in clinical studies. Based on rodent experiments, previous studies have identified that platelets stimulate liver regeneration after partial hepatectomy. However, the role of platelets in LDLT is controversial, as platelets are supposed to aggravate I/R injury in the liver. Recently, a rat model of partial liver transplantation (LT) was used to demonstrate that thrombopoietin-induced thrombocytosis prior to surgery accelerated graft regeneration and improved the survival rate after transplantation. It was clarified that platelet-derived liver regeneration outweighed the associated risk of I/R injury after partial LT. Clinical strategies to increase perioperative platelet counts, such as thrombopoietin, thrombopoietin receptor agonist and platelet transfusion, may improve graft regeneration and survival after LDLT.     

Problems in adult living donor liver transplantation using the right hepatic lobe

BACKGROUND: Adult living donor liver transplantation (LDLT) is now widely applied to patients, children or adults, and the graft extends from the left hepatic lobe to the right hepatic lobe. Harvesting the right hepatic lobe would mean putting the donor at high risk. The congestion of a graft may cause small-for-size syndrome. The safety of the donor and its evaluation, which are related to the outcome for the recipient,play an important role in LDLT. How to decrease the congestion of the graft is another challenge to transplant experts. DATA SOURCES: A literature search from MEDLINE about adult LDLT in recent years was made to analyze the safety of the living donor and the innovation of surgical techniques for preventing small-for-size syndrome. RESULTS: The top priority for adult LDLT is donor safety. Preoperative donor evaluation consists of three stages: phase 1 for general evaluation, phase 2 for laboratory tests, and phase 3 for radiological evaluation of graft volume and vessel anatomy. The potential pathogenic mechanisms of small-for-size syndrome seem to be related to persistent portal hypertension and portal overperfusion. Improved surgical techniques for decreasing portal hypertension and preventing congestion of a graft may reduce the incidence of small-for-size syndrome. The improved techniques include reconstruction of the tributaries of the middle hepatic vein, end-to-side portocaval shunting, ligation of the splenic artery, dual-graft transplantation, and modified reconstruction of hepatic veins. CONCLUSION: With the careful preoperative assessment and the safety of the living donor, as well as improved surgical techniques, adult LDLT using the right lobe is safe.     

Does liver-disease aetiology have a role in cerebral blood-flow alterations in liver cirrhosis?

BACKGROUND: Studies using brain-imaging techniques have shown changes in regional blood flow (rCBF) in patients with liver cirrhosis. It remains unknown whether the aetiology of liver disease accounts for these changes. AIMS: To evaluate whether the aetiology of liver cirrhosis is associated with different patterns of rCBF. MATERIALS AND METHODS: A total of 50 patients with end-stage liver disease and no overt encephalopathy were studied. Thirteen age-matched subjects admitted to the neurology department for headache were used as controls. Exclusion criteria were focal brain lesions, severe brain atrophy and any abnormalities found on computed tomography scan suggesting other central nervous system diseases, alcohol intake or use of neuroactive drugs for at least 6 months. rCBF was assessed using single-positron-emission tomography (SPECT) with 99mTc-hexamethylpropylene amine oxime (99mTc-HM-PAO) as a tracer in all patients and controls. The Mann-Whitney U test was used for statistical analysis. RESULTS: The liver-disease aetiology was as follows: alcoholic (A) in 19 patients; viral (V) (hepatitis B virus, hepatitis D virus, hepatitis C virus) in 14 patients; alcoholic with concomitant viral (A + V) in five patients; and cholestatic (C) (primary biliary cirrhosis, primary sclerosing cholangitis) in 12 patients. SPECT showed significantly lower rCBF in cirrhotic patients than in controls for most cortical and subcortical regions and in alcoholic and viral patients than in cholestatic liver disease patients for some cortical regions. When patients were grouped according to previous alcohol abuse (including cases with a concomitant viral aetiology), rCBF was significantly lower in the frontal superior, medial and temporal inferior regions in the alcoholic group. CONCLUSIONS: Cerebral blood flow is significantly lower in patients with liver cirrhosis than in controls and, among cirrhotics, it is lower in alcoholic and viral cirrhosis than in cholestatic liver disease. In patients with previous alcohol abuse, cerebral blood flow was significantly more reduced in the frontal and temporal regions compared with patients without previous alcohol abuse.     

Does heart transplantation confer additional benefit over medical therapy to patients who have waited >6 months for heart transplantation?

Objectives. This study compared the survival of patients with heart failure who have waited > 6 months for heart transplantation with that of patients who undergo heart transplantation after a similarly prolonged waiting period.Background. There are little data describing outcome in patients with severe heart failure who have waited for extended periods of time on the heart transplant waiting list.Methods. Sixty-three consecutive patients who spent >6 months on the heart transplant waiting list were examined. Mean (± SD) age was 53 ± 9 years, mean left ventricular ejection fraction was 19 ± 6%, and all were taking digoxin and diuretic and vasodilator agents. Patients who underwent transplantation during the follow-up period were censored from the pretransplantation analysis, and their survival was examined as part of the posttransplantation phase of the study.Results. Of the 63 original patients examined, 25 underwent transplantation, 10 during inotropic or mechanical circulatory support. The pretransplantation mortality rate was 6% at 6 months after the 6-month milestone on the waiting list, 12% at 12 months and 22% at 18 months. The posttransplantation mortality rate was 5% at 6 months, 10% at 12 months and 24% at 18 months. There were no differences in survival at any time between the two phases of the study.Conclusions. Survival of patients who have survived >6 months on the heart transplant waiting list is generally good. Although heart transplantation did not appear to confer additional survival advantage over medical therapy, a large proportion of the patients who underwent transplantation were critically ill at the time of transplantation and would undoubtedly have died of progressive heart failure had they not undergone transplantation. We conclude that heart transplantation should still be considered a therapeutic alternative in patients with heart failure even after a prolonged waiting period on the heart transplant waiting list.     

Significance of serum ��-d-glucan levels in recipients of living donor liver transplantation

Background/purpose

Early identification and treatment of fungal infections is essential for recipients of liver transplants, but the sensitivity of surveillance culture is insufficient. Measurement of the serum level of ??-d-glucan is a rapid diagnostic strategy for invasive fungal infection. We aimed to evaluate the significance of serum ??-d-glucan levels in transplant recipients after living donor liver transplantation (LDLT).

Methods

We retrospectively analyzed the clinical and laboratory data of 100 consecutive adult transplant recipients after LDLT performed between August 1997 and August 2009.

Results

Seventy-one had high serum ??-d-glucan levels (>20?pg/ml) after LDLT. Nearly half (47.2%) of the episodes of increase occurred within the first 5?days after surgery. The mortality rate of the recipients with high serum ??-d-glucan levels was similar to that of the recipients without high levels. However, in terms of the time line of increase, the recipients with high serum ??-d-glucan levels from 15?days onward after surgery showed a significantly higher mortality rate than those with high levels before 15?days after surgery (33.3 and 4.3%, respectively; p?Conclusions High serum levels of ??-d-glucan at late time points after LDLT indicate established fungal infection and higher mortality.     

Is an elderly recipient a risk for living donor adult liver transplantation?

BACKGROUND/AIMS: In cadaveric liver transplantation, it has been reported that elderly recipients over 60 years are at risk because of high incidence of complication and malignancy. However, in living-donor adult liver transplantation (LDALT), it is unclear whether the elderly recipient is risky or not risky. In this study, the outcome after LDALT of elderly patients has been evaluated. METHODOLOGY: One hundred twenty two consecutive LDALT recipients were studied. The recipients were divided into an elderly group (older than 60 yrs, n = 21), and a control group (younger than 60 yrs, n = 101). Comparative examination of background factors, postoperative complications and de novo malignancy was carried out. RESULTS: Elderly patients more frequently received transplantation for hepatocellular carcinoma. Pretransplant liver damage such as Child-Pugh, MELD or bilirubin level was same among the groups. There was no significant difference in posttransplant complications except renal failure. Postoperative renal failure (postoperative creatinine level over 2mg/dL) occurred in 29% (n = 5) of the elderly group vs. 8% (n = 6) of the control group. De novo malignancy occurred in 1 case (lung) in the elderly group and 1 case (Vater) in the control group. In the control group, the 1, 3 and 5 year patient survival rates were 78.5%, 73.1% and 71.4%, respectively. And in the elderly group, the 1, 3 and 5 year patient survival rates were 85.7%, 81.0% and 70.8%, respectively. CONCLUSIONS: It may be, we concluded that living donor adult liver transplantation is good treatment for end stage liver diseases in elderly recipients over 60 years. However caution should be taken in the administration of medicine, including immunosuppressants or antibiotics, do to a propensity for postoperative renal failure in elderly recipients.     

Is right lobe liver graft without main right hepatic vein suitable for living donor liver transplantation?

BACKGROUND Since the first living donor liver transplantation(LDLT) was performed by Raia and colleagues in December 1988, LDLT has become the gold standard treatment in countries where cadaveric organ donation is not sufficient. Adequate hepatic venous outflow reconstruction in LDLT is essential to prevent graft congestion and its complications including graft loss. However, this can be complex and technically demanding especially in the presence of complex variations and congenital anomalies in the graft hepatic veins.CASE SUMMARY Herein, we aimed to present two cases who underwent successful right lobe LDLT using a right lobe liver graft with rudimentary or congenital absence of the right hepatic vein and describe the utility of a common large opening drainage model in such complex cases.CONCLUSION Thanks to this venous reconstruction model, none of the patients developed postoperative complications related to venous drainage. Our experience with venous drainage reconstruction models shows that congenital variations in the hepatic venous structure of living liver donors are not absolute contraindications for LDLT.