Long-term survival after liver transplantation in 4,000 consecutive patients at a single center

Smoking behavior in liver transplant recipients

Long-term morbidity and survival after orthotopic liver transplantation (OLT) are to a large degree determined by cardiovascular disease and cancer. Tobacco use is a well-known risk factor for both. The aim of this study was to examine smoking behavior before and after OLT and to define groups at risk for resuming tobacco use after OLT. In addition, we looked for a relation between smoking and morbidity after OLT. All 401 adult patients with a follow-up of at least 2 years after OLT were included. Data were collected from the charts. A questionnaire about smoking habits at 4 time points before and after OLT was sent to all 326 patients alive, and 301 (92%) patients responded. Both before and after OLT, 53% of patients never used tobacco, and around 17% were active smokers. Of the active smokers during the evaluation for OLT, almost one-third succeeded in cessation, often during the waiting time for OLT. Twelve percent of former smokers restarted smoking, mainly after OLT. Tobacco use was the highest in patients with alcoholic liver disease (52% were active smokers before OLT, and 44% were after OLT) and the lowest in patients with primary sclerosing cholangitis (1.4% were active smokers before OLT). At 10 years, the cumulative rate of malignancies was 12.7% in active smokers versus 2.1% in nonsmokers (P = 0.019). No effect on skin cancer or cardiovascular disease was found. In conclusion, smoking is a serious problem after OLT and increases the risk for malignancy. Prevention programs should focus not only on active smokers but also on former smokers.

Clinical utility of microbubble contrast-enhanced ultrasound in the diagnosis of hepatic artery occlusion after liver transplantation

To evaluate the frequency of use and the diagnostic accuracy of real-time contrast-enhanced ultrasound (CEUS) in the diagnosis of hepatic artery occlusion after liver transplantation. One hundred and fifty-two liver transplantations in 142 adult subjects, comprising 80 male patients and 62 female patients, were studied. After surgery, liver circulation was routinely assessed by conventional Doppler ultrasound (US). Wherever the examiners were not confident about the state of the circulation, CEUS was performed with one or more doses of a sulfur hexafluoride (SF-6)-containing second-generation contrast agent intravenously. Clinical follow up including repeat Doppler US, computed tomographic angiography (CTA) or magnetic resonance angiography (MRA) of the liver vasculature were used as reference standards. During the first month after transplantation, Doppler US was inconclusive with regard to patency of the hepatic artery (HA) circulation in 20 (13 %) of 152 transplantations. CEUS was performed in these patients, and detected six cases of HA thrombosis (HAT) in five transplants. CEUS correctly ruled out HA occlusion in 15 transplants. All HA occlusions occurred during the first 14 days after transplantation. In the subset of transplantations examined with CEUS, the sensitivity, specificity and accuracy of CEUS were 100%. In approximately 13% of cases, conventional Doppler US did not provide sufficient visualization of the HA after liver transplantation. In these cases, correct diagnosis was achieved by supplementary CEUS.

Both tacrolimus and sirolimus decrease Th1/Th2 ratio, and increase regulatory T lymphocytes in the liver after ischemia/reperfusion

The protective effects of immunosuppressants against ischemia/reperfusion (I/R) injury have been attributed to their non-specific anti-inflammatory effect. However, these effects may also depend on their effect on T lymphocytes, which are increasingly considered to be key players in I/R. Here, we studied the effects of tacrolimus and sirolimus on lymphocyte subpopulations in an I/R rat model. The animals were treated with tacrolimus, sirolimus or vehicle, before undergoing a 60-min ischemia event of the right hepatic lobe, followed by excision of the remaining liver. After 2 h, I/R rats showed increased mortality, plasma lactate dehydrogenase (LDH) levels, hepatocyte apoptosis, liver histological injury and parenchymal infiltration by neutrophils, macrophages, NK cells and T lymphocytes. Most of the changes were antagonized by both immunosuppressants. Tacrolimus augmented the proportion of cycling cells in I/R rats, whereas sirolimus showed the opposite effect. The increased Th1/Th2 ratio found in I/R livers after 2 h was reverted by immunosuppressants, which also amplified the proportion of CD4(+)CD25(+)Foxp3(+) regulatory T lymphocytes at 24 h. The protective effects of both tacrolimus and sirolimus correlated well with a decreased ratio of proinflammatory to anti-inflammatory T lymphocytes, and with an increase in the Treg proportion. This suggests a new mechanism to explain the known beneficial effect shown by immunosuppressants early after I/R.

Outcome after liver transplantation for NASH cirrhosis

Nonalcoholic steatohepatitis (NASH) associated cirrhosis is an increasing indication for liver transplant (LT). The aim of this study was to determine outcome and poor predictive factors after LT for NASH cirrhosis. We analyzed patients undergoing LT from 1997 to 2008 at a single center. NASH was diagnosed on histopathology. LT recipients with hepatitis C, alcoholic or cholestatic liver disease and cryptogenic cirrhosis acted as matched controls. Ninety-eight LT recipients were identified with NASH cirrhosis. Compared to controls, NASH patients had a higher BMI (mean 32.3 kg/m2), and were more likely to be diabetic and hypertensive. Mortality after transplant was similar between NASH patients and controls but there was a tendency for higher earlier mortality in NASH patients (30-day mortality 6.1%, 1-year mortality 21.4%). Sepsis accounted for half of all deaths in NASH patients, significantly higher than controls. NASH patients > or =60 years, BMI > or =30 kg/m2 with diabetes and hypertension (HTN) had a 50% 1-year mortality. In conclusion, patients undergoing LT for NASH cirrhosis have a similar outcome to patients undergoing LT for other indications. The combination of older age, higher BMI, diabetes and HTN are associated with poor outcome after LT. Careful consideration is warranted before offering LT to these high-risk patients.

Renal biopsy in liver transplant recipients

BACKGROUND

Renal impairment post-liver transplant (LT) is often attributed to calcineurin inhibitors (CNIs). A renal biopsy can be a useful tool but may be complicated in LT recipients. We aimed to determine the clinical scenarios that prompted a decision to perform a renal biopsy in this patient population, to assess histological findings and evaluate patient management and survival and renal outcome.

METHODS

Information on clinical variables and renal histology was extracted from single-centre prospectively compiled databases from 1996 onwards.

RESULTS

Over 2100 adults received an LT in the time period studied, and 54 of these (35 males and 19 females) were referred for renal review. Of these, 43% underwent a renal biopsy. They had a higher creatinine (P = 0.02), a greater deterioration in creatinine over the year prior to review and were more likely to be nephrotic (both P < 0.01). Histological findings included hypertensive changes (44%), CNI nephrotoxicity (48%), IgA nephropathy (9%), membranoproliferative glomerulonephritis (17%), acute tubular necrosis (4%), crescentic glomerulonephritis (4%) and diabetic nephropathy (9%). Major bleeding complications occurred in 17%. Treatment changed in the majority but, it was not significantly different in the two groups. Although initial renal function was worse in the biopsied group, final patient and renal survival did not differ between the two groups.

CONCLUSION

A renal biopsy is a valuable tool in those with renal insufficiency and/or proteinuria and haematuria but the benefits must be weighed against the relatively high complication rate in LT recipients.

Liver retransplantation: a single-centre experience

BACKGROUND

The curative effect of liver transplantation for patients with end-stage liver disease was encouraging in recent years and the 5-year patient survival rate can reach up to 70%. However, some patients might lose grafts due to a variety of reasons, including bile duct complications, vascular complications, primary non-function, graft rejection and disease recurrence etc. Liver retransplantation (re-LT) was the only available means for those patients whose initial grafts had failed, but the inferior outcomes of re-LT compared to primary liver transplantation (PLT) continue to be a major concern. This study aimed to analyze the indications for re-LT, optimal timing of re-LT, and strategies to improve the survival rate after re-LT.

METHODS

From January 2001 to December 2006, we performed 738 liver transplants and 39 re-LT (5.3%) at our center. A retrospective analysis was performed to identify factors (indication for re-LT, preoperative score of model for end-stage liver disease (MELD), interval to re-LT from primary liver transplantation, methods of vascular and biliary reconstruction and common causes of death) associated with survival.

RESULTS

Mean follow-up period was 1.8 years (1 to 5 years). Patients with MELD score less than 20 were better than those whose MELD score was > 20 and MELD score > 30 (1-year survival, 80.0% versus 50.0% and 3/5). The perioperative survival rate of patients who received re-LT at an interval of more than 30 days and less than 8 days after the initial transplantation was higher than those who received retransplantation between 8 to 30 days following the first operation (88.5% and 74.3% versus 50.0%). The main causes of death were infection (60.0%), multiple organ failure (20.0%), vascular complications (10.0%) and biliary fistula (10.0%) in perioperative period. The overall patient survival rate of 1-month, 6-month and 1-year was 80.0%, 76.7% and 66.7%, respectively.

CONCLUSIONS

Our study suggested the favorable results after re-LT. The analysis also showed optimal timing of operation, refined surgical techniques, individualized immunosuppressive regimen and effective prophylaxis and treatment of perioperative infection play an important role in achieving a higher survival after re-LT.

Impact of tips preliver transplantation for the outcome posttransplantation

The effects of transjugular intrahepatic portocaval shunt (TIPS) on the survival of grafts and patients after liver transplantation (LTx) have only been documented in small series and with only a comparative description with non-TIPS recipients. We evaluated 61 TIPS patients who had a subsequent LTx and compared these with 591 patients transplanted with cirrhosis without TIPS. Pretransplant characteristics were similar between groups. Graft survival at 1, 3 and 5 years post-LTx was 85.2%, 77% and 72.1% (TIPS) and 75.3%, 69.8% and 66.1% (controls). Patient survival at the same points was 91.7%, 85% and 81.7%, respectively (TIPS) and 85.4%, 80.3% and 76.2% (controls). Cox regression showed the absence of TIPS pre-LTx, transfusion of >5 units of blood during LTx, intensive care unit (ICU) stay post-LTx >3 days and earlier period of transplant to be significantly associated with a worse patient and graft survival at 1 year. Migration of the TIPS stent occurred in 28% of cases, increasing the time on bypass during LTx, but was not related to graft or patient survival. TIPS may improve portal supply to the graft and reduce collateral flow, improving function. This may account for the improved adjusted graft and patient survival by Cox regression at 12 months. Long-term survival was not affected.

Risk of malignant neoplasms after liver transplantation: a population-based study

Posttransplant malignancies have become a serious long-term complication after liver transplantation. Our aim was to compare the incidence of posttransplant cancers with national cancer incidence rates. The study included all Finnish liver transplant patients transplanted at the Helsinki University Central Hospital between 1982 and 2005. The cohort was linked with the nationwide Finnish Cancer Registry. Observed numbers of cancers were compared to site-specific expected numbers based on national cancer incidence rates stratified by age, sex, and calendar time. The standardized incidence ratios (SIRs) were calculated as observed-to-expected ratios. Thirty-nine posttransplant de novo cancers and 11 basal cell carcinomas were found in the cohort of 540 patients during 3222 person years of follow-up. The overall SIR was 2.59 (95% confidence interval 1.84-3.53). SIR was higher for males (SIR 4.16) than for females (SIR 1.74), higher among children (SIR 18.1) than among adults (SIR 5.77 for ages of 17-39 years and 2.27 for ages >/= 40 years), and more elevated in the immediate posttransplant period (SIR 3.71 at < 2 years) compared to later periods (SIR 2.46 at 2-10 years and 1.53 at >10 years). The most common cancer types were nonmelanoma skin cancer (SIR 38.5) and non-Hodgkin lymphoma (SIR 13.9). Non-Hodgkin lymphoma was associated with male gender, young age, and the immediate posttransplant period, whereas old age and antibody induction therapy increased skin cancer risk. In conclusion, cancer incidence is increased among liver transplant patients compared to the general population. This study points out the importance of cancer surveillance after liver transplantation.

A decade of right liver adult-to-adult living donor liver transplantation: the recipient mid-term outcomes

OBJECTIVE

We analyzed a single center's experience over a decade of right liver living donor liver transplantation (RLDLT).

SUMMARY BACKGROUND DATA

To define the donor risk and recipient benefit ratio, midterm outcome of this life-saving treatment modality ought to be known.

METHODS

Consecutive patients from 9 May 1996 were included. Era I comprised the first 50 patients and Era II comprised the remaining 184 patients. Their midterm outcomes were compared with patients receiving deceased donor liver transplantation (DDLT) of the same period in the same center.

RESULTS

With a median follow-up of 48 months, the 1-, 3-, and 5-year overall survival rates were 93.2%, 85.7%, and 82.4%, respectively and were comparable with those of DDLT (n = 131) (90.1%, 87.7%, and 85.2%) (P = 0.876). Hospital mortality decreased from 16% in Era I to 2.2% in Era II (P = 0.000). Reduced hospital mortality improved the overall survival rates from Era I to Era II (78%, 74%, and 72% vs. 97.3%, 88.7%, and 85.1%, respectively) (P = 0.003). The 5-year survival rate of recipients with hepatocellular carcinoma (HCC) (n = 65) was 65.7%. Starting from Era II, excellent 5-year survival of recipients without HCC was achieved as compared with DDLT in the same period (93.4% vs. 88.2%) (P = 0.493). The 5-year survival rates of recipients with HCC within the Milan criteria of Era II and DDLT in the same period were 72.0% and 100%, respectively (P = 0.091). Multivariate analysis indicated that only Era I (relative risk = 2.606; P = 0.005) and pretransplant HCC (relative risk = 2.729; P = 0.002) adversely affected overall survival.

CONCLUSIONS

High midterm survivals were achieved by reduction of hospital mortality through accumulation of experience and transplanting recipients with low chance of recurrence of HCC. RLDLT could be considered as a legitimate alternative to DDLT.

Liver transplantation for hepatocellular carcinoma: Hangzhou experiences

INTRODUCTION

Liver transplantation (LT) has been the treatment of choice for patients with hepatocellular carcinoma (HCC). This study was designed to summarize our experience in LT for HCC patients and establish a new set of criteria for patient selection and prognosis prediction.

MATERIALS AND METHODS

Data of 195 patients with HCC were retrospectively analyzed and various clinical and pathological factors for survival and tumor-free survival were examined by univariate and multivariate analyses.

RESULTS

Macrovascular invasion, preoperative serum alpha fetoprotein (AFP) level, tumor size, multifocality, histopathologic grading, distribution, and cirrhosis background were significant factors for survival and tumor-free survival by univariate analysis. Multivariate analysis identified macrovascular invasion, tumor size, preoperative AFP level, and histopathologic grading were prognostic factors independently associated with patient survival or tumor-free survival (RR=1.688-2.779, P=0.000-0.034). Based on the prognostic stratification of different risk groups of patients without macrovascular invasion, Hangzhou criteria was established, containing one of the two following items: (a) Total tumor diameter less than or equal to 8 cm; (b) total tumor diameter more than 8 cm, with histopathologic grade I or II and preoperative AFP level less than or equal to 400 ng/mL, simultaneously. The difference between survival curves of patients fulfilling Milan criteria (n=72) and patients fulfilling Hangzhou criteria (n=99) did not achieve statistical significance (5-year survival rates: 78.3% vs. 72.3%, P>0.05). Of the patients exceeding Milan criteria (n=123), those who fulfilled Hangzhou criteria (n=26) also had better prognosis than the others (n=97) (P=0.000).

CONCLUSION

The results of this study show a reliable and feasible candidates selection and prognostic criteria of LT in HCC patients.

Health-related quality of life in adult transplant recipients more than 15 years after orthotopic liver transplantation

With continuously rising survival rates following orthotopic liver transplantation (OLT), health-related quality of life (HRQOL) of transplant recipients becomes increasingly important. Recipients more than 15 years after OLT were studied retrospectively. HRQOL in 104 adult liver transplant recipients surviving more than 15 years after OLT was assessed using the German Version of the 36-Item Health Survey (SF-36). Liver transplant recipients surviving more than 15 years after OLT scored lower in all categories of SF-36 revealing a poor HRQOL in comparison to the German reference population. A statistical significance was reached in almost all SF-36 categories with the exceptions of mental health and bodily pain, where our study population scored similarly to the reference population. Job rehabilitation after OLT had a positive effect on HRQOL. Patients who returned to their job during the first year after OLT scored significantly higher in the SF-36 categories of physical functioning and role physical. Marital status and the immunosuppression used didn't affect HRQOL as there was no statistical significance reached in any of the comparisons performed. More than 15 years after OLT, long-term survivors present a poor HRQOL comparable to the reference population. Occupational rehabilitation was the only factor shown to positively influence long-term HRQOL.

The impact of donor age on the outcome of adult living donor liver transplantation

BACKGROUND

The negative effects of increased donor age on liver transplantation became evident in deceased donor liver transplantation. In living donor liver transplantation (LDLT), the details remain unclear.

METHODS

Initially, 137 adult LDLT recipients from August 1996 to May 2005 were divided into two groups (donors <50 years of age: n=99, donors >or= 50 years of age: n=38) for the retrospective study. Then, 24 recipients who received LDLT from June 2005 to July 2006 were divided into two groups: group 1 (donors <50 years of age, n=14) and group 2 (donors >or= 50 years of age, n=10) and enrolled in the prospective study to analyze their clinical course and prognostic factors in the aged graft.

RESULTS

In the retrospective study, the younger donor group had significantly better survival than that of the aged donor group (P=0.015, Log rank test). In the prospective study, the postoperative graft functions showed that the serum total bilirubin levels were significantly lower in group 1 (P<0.02, by ANOVA analysis). The phosphorylated-Signal Transducer and Activator of Transcription3 expression at 4 hr after reperfusion (RT2) in group 2 was significantly lower than that in group 1. At RT2, the expressions were up-regulated in group 1, but were down-regulated in group 2. The serum 8-hydroxydeoxyguanosine value became significantly higher in group 1 two weeks after LDLT.

CONCLUSIONS

In the near term, Signal Transducer and Activator of Transcription3 gene induction during cold preservation may be of great use in improving the outcome of aged grafts in LDLT.

Orchiectomy or testosterone receptor blockade reduces intestinal mucosal damage caused by ischemia-reperfusion insult

The aim of the present study was to investigate whether orchiectomy or administration of flutamide an antagonist of the testosterone receptor can reduce oxidative stress and histologic damage in the rat small bowel subjected to mesenteric ischemia/reperfusion (I/R) injury. A total of 32 Sprague-Dawley rats were divided into four groups. Group 1 was control (sham), group 2 was I/R, group 3 was I/R plus orchiectomy (orchiectomy was performed 14 days before I/R), group 4 was I/R plus flutamide (flutamide was given throughout 14 days before mesenteric IR). Rats were subjected to 45 min of mesenteric ischemia followed by 3 h of reperfusion. The levels of ileal malondialdehyde (MDA) and nitric oxide (NO) were found to be significantly lower in orchiectomy and flutamide treatment groups compared with I/R group (P < 0.05). The histopathological injury scores were consistent with the MDA and NO levels. These results suggest that castration or testosterone receptor blockade decreases the level of intestinal I/R injury in male rats and it is an another example for disease variations based on gender differences.

Our experience in liver transplantation in patients over 65 yr of age

OBJECTIVES

The aim of this study was to analyze short- and long-term results of liver transplantation (LT) in patients over 65 yr.

MATERIAL AND METHODS

Between 1996 and 2004, 386 patients underwent 415 LT at our center. The main indication for LT was post-necrotic cirrhosis in 59%, followed by hepatocellular carcinoma (HCC) over cirrhosis in 33%. Half of the patients (53%) were hepatitis C virus (HCV) +. Overall, 72 patients were >65 yr of age. Actuarial survival, causes of mortality and postoperative complications were compared between groups: patients under and over 65 yr. Risk factors for poor outcome in patients over 65 yr were also analyzed.

RESULTS

The older group had more patients at Child A stage, more HCC as an indication for LT and more HCV (+) patients, p < 0.05. No differences were observed in donor and surgery characteristics, except for lower multi-transfusion and higher incidence of grafts with steatosis in the older group (p < 0.05). Actuarial survival at one, three, five and 10 yr was 82%, 75%, 72%, and 70% for the <65 yr group vs. 77%, 66%, 55%, and 55% for the >65 yr group (p = 0.03). Main causes of mortality in patients >65 yr were recurrence of underlying disease and medical causes. In the older age group, fewer infections (p = ns) and rejections (p = 0.017) occurred in the postoperative period. Risk factor for poor outcome in the group of patients over 65 yr in multivariate analyses was pre-LT renal insufficiency (odds ratio 3.5, p = 0.002, 95% confidence interval 1.58-7.82).

CONCLUSION

Results in patients >65 yr are comparable to those <65 yr if older LT candidates are carefully selected. Overimmunosuppression should be avoided in older candidates, as its effects could worsen the pre-existing diseases common in elderly patients.

Historical perspective of living donor liver transplantation

Living donor liver transplantation (LDLT) has gone through its formative years and established as a legitimate treatment when a deceased donor liver graft is not timely or simply not available at all. Nevertheless, LDLT is characterized by its technical complexity and ethical controversy. These are the consequences of a single organ having to serve two subjects, the donor and the recipient, instantaneously. The transplant community has a common ground on assuring donor safety while achieving predictable recipient success. With this background, a reflection of the development of LDLT may be appropriate to direct future research and patient-care efforts on this life-saving treatment alternative.

The effect of estrogen on hepatic microcirculation after ischemia/reperfusion

BACKGROUND AND AIMS

Gender dimorphism in clinical manifestation of sepsis, hemorrhage, and trauma is still under investigation. Several experimental studies have indicated a protective effect of estrogen. Nonetheless, the effect of gender on hepatic ischemia/reperfusion remains controversially discussed, and the influence of estrogen is still unclear. In the present study, we investigated whether hepatic ischemia/reperfusion (I/R) injury is gender-dependent and if hepatic microvascular reperfusion injury can be prevented by estrogen.

MATERIALS AND METHODS

Eight female and eight male Sprague-Dawley rats were subjected to 90 min left lobar ischemia followed by 60 min reperfusion. Additional six males were pretreated with 17beta-estradiol 24 h before I/R. Six female and six male rats served as nonischemic sham animals. By means of intravital microscopy, sinusoidal perfusion, leukocyte-endothelial cell interaction, and Kupffer cell activity were analyzed. Finally, arterial blood and liver tissue samples were taken for histomorphological analysis and liver enzyme determination.

RESULTS

After hepatic ischemia/reperfusion, animals revealed a significant gender-specific impairment of hepatic microcirculation, whereas Kupffer cell depression, sinusoidal perfusion failure, leukocyte-endothelial cell interaction within post sinusoidal venules, and parenchymal liver cell damage were more pronounced in male animals. Pretreatment with estrogen caused a normalization of Kupffer cell dysfunction and an amelioration of sinusoidal perfusion failure and venular leukocyte-endothelial cell interaction. However, estrogen did not protect from manifestation of post ischemic parenchymal cell damage.

CONCLUSION

Hepatic ischemia and reperfusion generate a gender-specific occurrence of microvascular injury, which seems to be partially mediated by estrogen. However, additional factors may contribute to the initial post ischemic parenchymal cell damage.

Long-term results after liver transplantation

Liver transplantation (OLT) has become a successful surgical therapy for terminal liver failure. We here report about long-term results of OLT in a single center over a period of 15 years. Between 1988 and 2002, 1365 adult OLTs were performed. Mean follow-up was 103 +/- 56 months. Main indications for OLT were viral-induced cirrhosis (27.1%), alcoholic liver disease (21%), tumors (15.7%) and cholestatic liver disease (14.6%). Retransplantation was necessary in 120 (9.6%) patients because of initial nonfunction (26.9%), recurrence of underlying disease (20.2%), acute and chronic rejection (16.8%) or thrombosis of the hepatic artery (16.8%). 275 patients (22.1%) died. Causes of death included recurrence of disease (32.1%), infections (21.8%), de novo malignancies (13.5%) and cardiovascular disease (11.6%). Patient survival after OLT was 91.4%, 82.5%, 74.7% and 68.2% after 1, 5, 10 and 15 years, and graft survival was 85.8%, 75.3%, 67.3% and 61.7% after 1, 5, 10 and 15 years, respectively. Patient survival after retransplantation was 81.6%, 68.8% and 57.1% and 48.0% after 1, 5, 10 and 15 years. This analysis reveals excellent long-term results after OLT achieved in a single center.

Intraoperative flow measurement of native liver and allograft during orthotopic liver transplantation in children

Hepatic hemodynamic changes during liver transplantation (OLT) in children have not yet been studied. We measured intraoperative portal vein flow (PVF) and hepatic arterial flow (HAF) (mL/min) in 53 children and 58 grafts during OLT. Flows were measured in the native organ and in the allograft. In the native liver, PVF and HAF are similar; after transplantation they return to the physiological situation. No flow differences were seen between whole and partial grafts. Among the 8 (14%) portal vein thromboses, PVF was lower in both the native liver and the graft than in the no thrombosis group (P < .05). PVF <5 mL/min/kg was a risk factor to develop PV thrombosis. No graft loss occurred in 3 cases without PVF at the time of OLTs despite the observation that repermeabilization was not possible. In 4 patients with PVF <5 mL/min/kg, after tying a spontaneous spleno-renal shunt (n = 3) or performing a porto-renal vein anastomosis (n = 1), PVF reached >20 mL/min/kg, avoiding thrombosis. In conclusion, PVF and HAF measurements during pediatric OLT may predict patients at high risk for development of PV thrombosis.

Use of Everolimus as a Rescue Immunosuppressive Therapy in Liver Transplant Patients With Neoplasms

Everolimus is a new immunosuppressant with antitumoral properties and few side effects, but limited use in liver transplantation. The aim of the present study was to evaluate the effect on survival and safety of everolimus in post liver transplantation neoplasms in a single center. Ten liver transplant recipients with a posttransplant diagnosis of neoplasm received everolimus during a median of 12.7 (5.5-27.5) months; median survival was 21.3 (7.5-40.5) months. The probability of survival of everolimus group was significantly greater than the observed in a historical cohort of 14 liver recipients with comparable tumors who did not receive everolimus (100%, 90%, 72% vs. 50%, 29%, 14%) at 6, 12, and 24 months, respectively (HR=4.6, 95% confidence interval: 1.3-16.4; P=0.008). During everolimus therapy no patients showed rejection. Renal function improved in three patients. Furthermore, severe adverse effects and infections were infrequent. In summary, everolimus seems safe for liver transplant recipients with cancer and may improve short-term survival, but further studies are needed to determine long-term benefits and safety.

Liver Transplantation in Childhood With More Than 10 Years of Follow-up: Analysis of a Single-Center Experience

We pioneered pediatric liver transplantation (OLT) in Spain (June 1985). The aim of this study was to evaluate the current status of our OLT recipients with more than 10 years follow-up.

MATERIALS AND METHODS

The 50 patients with >10 years follow-up had a mean age at OLT of 5.6 years with 60% showing a main indication of biliary atresia. All but one (tacrolimus) received cyclosporine.

RESULTS

No patient loss occurred among these patients. Eighteen patients had follow-up >15 years and 12 >20 years. The incidence of acute rejection was 56%; chronic rejection, 16%; and lymphoproliferative disorders, 12%. Seven (14%) required retransplantation at a mean of 4.2 years after the first OLT due in four instances to chronic rejection. After 10 years of follow-up, one patient developed portal vein thrombosis and three biliary strictures. All patients remain on immunosuppression. In 64% cyclosporine was switched to tacrolimus or another agent. One patient developed acute rejection at 19.2 years. In 14% of patients the liver function test is abnormal with serum creatinine is >1.5 mg/dL in 10%; one requires insulin and three, antihypertensive drugs. Noncompliance with medications was detected in 10%. Three recipients had offspring.

CONCLUSIONS

OLT was an effective treatment with a good quality of life also on long-term follow-up.

Late graft loss or death in pediatric liver transplantation: an analysis of the SPLIT database

Late graft loss (LGL) and late mortality (LM) following liver transplantation (LT) in children were analyzed from the studies of pediatric liver transplantation (SPLIT) database. Univariate and multivariate associations between pre- and postoperative factors and LGL and LM in 872 patients alive with their primary allografts 1 year after LT were reviewed. Thirty-four patients subsequently died (LM) and 35 patients underwent re-LT (LGL). Patients who survive the first posttransplant year had 5-year patient and graft survival rates of 94.2% and 89.2%, respectively. Graft loss after the first year was caused by rejection in 49% of the cases with sequelae of technical complications accounting for an additional 20% of LGL. LT for tumor, steroid resistant rejection, reoperation in the first 30 days and >5 admissions during the first posttransplant year were independently associated with LGL in multivariate analysis. Malignancy, infection, multiple system organ failure and posttransplant lymphoproliferative disease accounted for 61.8% of all late deaths after LT. LT performed for FHF and tumor were associated with LM. Patients who are at or below the mean for weight at the time of transplant were also at an increased risk of dying. Frequent readmission was also found to be associated with LM.

A cause-specific hazard rate analysis of prognostic factors among 877 adults who received primary orthotopic liver transplantation

BACKGROUND

In orthotopic liver transplantation (OLT) distinct causes of graft failure (GF) and death with a functioning graft (DFG) exist. Prognostic factors for one failure type may be distinctly different from those predictive of other types, and an accurate portrayal of these relationships may more clearly explain each factor's importance.

METHODS

A multivariable cause-specific hazard (CSH) rate analysis using Cox stepwise regression was performed among 877 adults who received primary OLT during 1996-2004 with tacrolimus+steroids as immunosuppression.

RESULTS

Older donor age (P=0.004) implied greater primary dysfunction GF, while primary sclerosing cholangitis (PSC; P=0.0002) implied greater vascular thrombosis GF. Recurrent nonmalignant liver disease GF was higher among hepatitis C virus patients (P<0.00001), and younger recipient age (P=0.005) implied greater death from recurrent (metastatic) hepatocellular carcinoma. African-American race (P<0.00001), PSC (P=0.003), and younger recipient age (P=0.005) were independently associated with greater GF due to chronic rejection. Older donor age (P=0.003) implied greater infection DFG, while older recipient age (P=0.003) and pretransplant diabetes (P=0.03) were independently associated with greater cardiovascular/cerebrovascular DFG. Finally, most of these cause-specific predictors were not significant in an overall Cox model for graft survival.

CONCLUSIONS

The CSH approach should be more widely used in investigations of prognostic factors. The result of older donor age implying greater primary dysfunction GF and infection DFG but having no association with other failure types demonstrates that its impact is specific to the graft's early posttransplant functional status. In addition, while recipient age was an important prognosticator, its direction of association reverses depending upon the outcome being analyzed.

Histidine-tryptophan-ketoglutarate solution vs. University of Wisconsin solution for liver transplantation: a systematic review

University of Wisconsin (UW) solution has been recognized as the gold standard in liver preservation, but its limitations are becoming obvious, such as risk of biliary complications and its high cost. Alternatively, the effects of histidine-tryptophan-ketoglutarate (HTK), such as improved biliary protection and low cost, have been observed. This systematic review is conducted to compare the efficacy and safety of these 2 solutions. Databases from 1966 to June 2006 were searched. Randomized clinical trials (RCTs) and cohort studies comparing HTK and UW solutions for liver transplantation were included. Ten articles including 11 comparisons (1,200 patients) met the inclusion criteria, containing 2 RCTs and 9 cohort studies. No marked differences existed between the 2 groups in patient and graft survival rates, acute rejection, primary nonfunction, primary dysfunction, delayed graft function, and ALT and AST levels after transplantation. The only positive result was observed in the bile production after deceased donor liver transplantation (DDLT), which was statistically significantly higher in HTK group than that of UW group (95% confidence interval, 18.65-57.47; P=0.0001). Although the difference in biliary complications between the 2 groups did not reach statistical significance, HTK was thought to be more effective for biliary tract flush and prevention of biliary complications in some studies. There was no statistically significant difference of effects (except bile production) between HTK and UW. But trends were documented in some studies for the superiority of HTK in biliary tract flush, prevention of biliary complications, and cost saving. Adequately powered RCTs with longer follow-up periods are required to evaluate the long-term effect of these 2 solutions.

Post-transplant lymphoproliferative disease in liver transplantation

Post-transplant lymphoproliferative disease (PTLD) is a well recognized complication of solid organ transplantation and therapeutic immunosuppression, first reported in 1968. PTLD incorporates a spectrum of abnormalities ranging from a benign infectious mononucleosis-like illness to non-Hodgkin's lymphoma with nodal and extranodal site involvement. The first liver transplant was performed at our institution in January 1982. This retrospective study examined the incidence of PTLD, reason for the original transplants, presenting symptoms, radiological findings, immunosuppression regimens and outcomes of these patients. From a total of 2005 adult liver transplants, 23 patients (1.1%) were identified with PTLD. The average age of these patients at the time of transplant was 46.5 years, with a ratio of female-to-male of 14:9. Indication for transplant ranged from primary biliary cirrhosis (eight patients) to epitheloid haemangioendothelioma (one patient). The average time interval between transplant and diagnosis of PTLD was 50 months. Imaging abnormalities identified included generalized lymphadenopathy, liver and portal masses, splenic enlargement, bowel, eye, cerebral and neck involvement; and in two patients, no radiological abnormality. The most common histological findings ranged from B-cell non-Hodgkin's lymphoma (five patients) to early PTLD in one patient. Our rate of PTLD is lower compared with published literature and demonstrates a much longer time interval from transplant to occurrence of PTLD than previously appreciated. This could be secondary to a low immunosuppression therapy followed at our institution. From a few months to several years after liver transplantation, the radiologist needs to be alert to the possibility of PTLD and thorough imaging is required to detect the wide variety of potential presentations.

Postresection hepatic failure: successful treatment with liver transplantation

Postoperative liver failure (PLF) is a rare but often fatal complication of major hepatic resection. Use of orthotopic liver transplantation (OLT) for PLF remains undefined. We conducted a retrospective review of 435 patients who underwent hepatic resection between 1990 and 2004; 9 of them (2.0%) developed PLF. Indications for resection included primary hepatic malignancies (8), colonic metastases (2), and echinococcic cyst (1); all resections were multisegmental, 6 were extended, and 2 were lobectomies. A total of 7 patients underwent OLT at a mean of 25 days after resection. Patients developing PLF had significantly lower preoperative platelet counts and significant elevations of total bilirubin, direct bilirubin, prothrombin time, and international normalized ratio (INR) by postoperative day 2. Pathological cirrhosis and extended right lobectomy were associated with significantly increased risk of PLF. Following OLT, there were no in-hospital deaths, but 1 patient required retransplantation for primary nonfunction. Mean survival with and without OLT was 42.2 and 1.4 months, respectively (P = 0.03). Following OLT, 1- and 5-yr patient survivals were 88% and 40%, respectively; 1- and 5-yr graft survivals were 75% and 34%, respectively. In conclusion, patients with low platelets, biopsy-proven cirrhosis, or those undergoing extended resection are at increased risk for PLF. OLT for PLF has significant morbidity but allows salvage of an otherwise fatal condition.

Primary nonfunction (PNF) in the MELD Era: An SRTR database analysis

PNF following liver transplantation (LT) is an infrequent but life-threatening complication. Liver allocation under MELD is based upon recipient severity of illness, a known risk factor for the occurrence of PNF. The incidence of PNF since the application of MELD has not previously been reported. The SRTR database was studied since inception of MELD until September 2004 for all adult recipients of deceased donor LT. PNF was defined as graft loss or death within 14 days of LT secondary to PNF or without defined cause. A total of 10545 transplants met inclusion criteria and PNF occurred in 613 (5.81%) of recipients. Univariate analysis demonstrated donor age, serum creatinine >1.5 mg/mL, hypertension and CVA as risk factors for PNF. Recipient factors included life support, mechanical ventilation, use of inotropes, hemodialysis, initial status 1 and use of a shared transplant. In the multivariate model only donor age and recipient serum creatinine, bilirubin, on life support and status 1 at transplant were significant risk factors for PNF. In this analysis of PNF in the MELD era the incidence of PNF does not appear to have increased from prior reports. Risk factors for PNF are related to donor age and severity of recipient illness.

Extended Donor Criteria Have No Negative Impact on Early Outcome After Liver Transplantation: A Single-Center Multivariate Analysis

The organ shortage has driven many transplant centers to accept extended donor criteria and to modify graft allocation policies. This study was designed to analyze the impact of applying extended donor criteria (EDC) in orthotopic liver transplantation (OLT). Between December 2001 and December 2004, we performed 165 primary cadaveric whole OLTs. Up to three EDC, that is, ventilation >7 days; aminotransferases (ALT or AST) >3 x normal; bilirubin >3 mg/dL; anti-HBc or HBs Ag positivity; donor age >65 years; liver steatosis >40%; donor body mass index >30; cold ischemia time >14 hours; peak serum Na(+) >165 mmol/L; history of extrahepatic malignancy; or previous drug abuse were present in 55% of all grafts. Both univariate and multivariate analysis revealed that EDC status had no effect on graft or patient survival, the necessity for retransplantation, the length of intensive care/intermediate care unit stay, mechanical ventilation, complications, or posttransplant laboratory findings. Recipient age of >/=55 years was the only independent prognostic factor for survival, regardless of EDC. These findings suggested that the use of grafts from EDC donors are safe and expand the donor pool.

Liver transplantation()

Orthotopic liver transplantation (OLT) involves the substitution of a diseased native liver with a normal liver (or part of one) taken from a deceased or living donor. Considered an experimental procedure through the 1980s, OLT is now regarded as the treatment of choice for a number of otherwise irreversible forms of acute and chronic liver disease.The first human liver transplantation was performed in the United States in 1963 by Prof. T.E. Starzl of the University of Colorado. The first OLT to be performed in Italy was done in 1982 by Prof. R. Cortesini. The procedure was successfully performed at the Policlinico Umberto I of the University of Rome (La Sapienza).The paper reports the indications for liver transplantation, donor selection and organ allocation in our experience, surgical technique, immunosuppression, complications and results of liver transplantation in our center.

De novo esophageal neoplasia after liver transplantation

The purpose of the study was to determine the incidence, risk factors, treatment, and influence on survival of patients with de novo esophageal cancer after liver transplantation (LT). From 1988 to 2006, 1,926 patients underwent LT in our institution. A total of 9 patients (0.5%) developed a de novo esophageal cancer and 1 patient a cancer of the cardia (0.05%). A retrospective analysis was performed to reveal underlying diseases, timeframes between LT and appearance of cancer, predisposing factors, cancer therapy, complications, immunosuppressive regimens, and survival. Of our 10 patients, 7 (70%) suffered from esophageal squamous cell carcinoma (SCC) and 3 patients (30%) developed an adenocarcinoma, including the patient with cancer of the cardia. A total of 9 patients were transplanted due to alcoholic cirrhosis; 1 patient suffered from hepatocellular carcinoma in nonA-nonB hepatitis-related cirrhosis. Median time to tumor diagnosis was 51 months after transplantation. A total of 5 patients were treated conservatively with combined radiochemotherapy and 5 underwent surgical resection. Patients with radiochemotherapy showed a mean survival of 14.8 months vs. 24.8 months for the patients of the surgery group. No major postoperative complication has been observed. A total of 2 patients of the surgery group are still alive after a follow-up of 15 and 89 months. In conclusion, de novo esophageal and cancer of the cardia after LT is a rare event. In spite of immunosuppression, no increased complication rate has been observed. Patients may have a survival benefit from surgical resection.

Survival analysis of liver transplant patients in Canada 1997-2002

Liver transplantation is an important health care issue for Canadians. Very few studies have assessed survival and determinants of survival in liver transplant patients in Canada.

METHODS

We carried out an epidemiological analysis of 1 year survival and determinants of 1 year survival in liver transplant patients, using Canadian Organ Replacement Registry data (1997-2002). Survival curves were plotted by the Kaplan-Meier method. Cox proportional hazards analysis was applied to evaluate hazard ratios with different age groups, gender, ethnicity, blood groups, donor type, pretransplantation medical status, and HBV infection status.

RESULTS

A total of 1164 liver transplant patients were included in the analysis. One-year survival rate was 84.7%. Male recipients had a 21% higher risk of developing organ failure than females. Recipients over 60 years of age had a 5% lower survival probability in comparison with recipients below 20 years of age. Pacific Islanders and Aboriginals had 32% and 9% lower survival probabilities, respectively, in comparison with Caucasians. Type B blood recipients had a 12% higher survival probability, whereas type AB blood recipients had a 7% lower survival probability compared with type O blood recipients. Twenty-six live organ recipients had 40% higher survival probabilities than 1138 cadaveric organ recipients. Patients with fulminant hepatitis (status 3F) had the highest survival, while patients with fulminant failure in ICU with intubation/ventilation (status 4F) had the lowest survival. One hundred sixty-seven recipients with positive HBsAg antigen showed 10% lower survival probability than 997 cases with negative HBsAg antigen.

CONCLUSION

In Canada, the first year survival rate is about 85%, which is comparable with other industrialized countries. Type of donor organs and recipient gender, ethnicity, ABO blood group, pretransplantation medical status, and HBV infection status had significant affects on the recipient survival.

Life expectancy of adult liver allograft recipients in the UK

BACKGROUND

Liver transplantation is a very successful therapy for those with end stage disease. Although there are numerous data on patient and graft survival after liver transplantation, life expectancy and possible loss of life (compared with a normal matched population) in those who survive remains unknown.

AIMS

To assess the life expectancy and life years lost of adult liver allograft recipients, compared with an age and sex matched UK population to provide patients with more information and to improve the use of a scarce resource.

METHODS

Using the National Transplant Database held by UK Transplant, on over 3600 adult liver allograft recipients transplanted between 1985 and 2003, we analysed survival of all adults who survived more than six months after transplantation and compared survival after transplantation with national age and sex matched controls to assess life years lost.

RESULTS

Estimated median survival time of the analysis cohort of 2702 adult liver allograft recipients was 22.2 years (95% confidence interval 19.3-25.6), with an estimated loss of seven life years compared with an age and sex matched population.

CONCLUSIONS

Overall, female recipients have a longer life expectancy and lose fewer life years than male recipients. While younger recipients have a longer life expectancy, they also lose more life years. Those transplanted for cancer, hepatitis C virus infection, and alcoholic liver disease had the greatest loss of life years.

Trends and experiences in liver retransplantation over 15 years

Compared to primary liver transplantation (LT), the inferior results in the outcome of liver retransplantation (re-LT) continue to be a major challenge. The purpose of this study was to analyze changes in and outcomes of re-LT over a period of 15 years at the Charité Virchow Clinic. Between 1989 and 2003, we performed 1,619 LTs and 157 re-LTs (9.7%) in 1,462 patients. A total of 119 retransplants (50 females, 69 males) were analyzed after consideration of exclusion criteria: recipient age <16 years, second re-LT, primary LT as split-liver or living-related LT, or combination with renal transplantation or Whipple operation. All patients received a whole-size organ. Mean follow-up was 62 months (6 days to 187 months). The main indications for re-LT were initial nonfunction (26.9%), recurrence of viral-induced hepatitis (20.2%), or acute and chronic rejection or thrombosis of the hepatic artery (both 16.8%). The main causes of death were bacterial infections (26.0%) as well as bleeding complications or recurrence of disease (both 16.0%) within the first postoperative month. Overall, 50 out of 119 patients (42%) died after re-LT, 26 patients within the first 3 months and 38 within 1 year. Overall patient survival was 89.9% after 1 month, 78.2% after 1 year, and 67.1% after 5 years. In conclusion, our study showed good clinical results after re-LT. Apart from the changing indications for re-LT with an increasing amount of initial organ failure and hepatic artery thrombosis, the analysis also showed a decreasing amount of complications such as rejection, ischemic type biliary lesions, and recurrence of the disease with unchanged outcome over a period of 15 years.

Expression of toll-like receptors and type 1 interferon specific protein MxA in biliary atresia

Viral infection and type I interferon have been implicated in the pathogenesis of biliary atresia (BA), but the expression of toll-like receptors (TLRs) that recognize viruses, as well as of type 1 interferon specific signaling molecules are still unknown in BA. Fresh liver tissues were obtained from patients in early and late stage of BA and from patients with choledochal cyst (CC), as well as from normal controls receiving liver resection for benign lesion other than cholestasis or fibrosis. Archived liver tissues from patients with neonatal hepatitis (NH) were obtained for immunohistochemical studies. TLR2, 3, 4, 7 and 9 that recognized Gram-positive bacteria, double-stranded RNA virus, lipopolysaccharide, single-stranded RNA virus and DNA virus, respectively, were studied. Real-time quantitative reverse transcription polymerase chain reaction (QRT-PCR) was used to quantitate TLR, type I interferon specific molecule MxA, interleukin-6 (IL-6) and IL-8 mRNA expression and immunohistochemistry for TLR 7 and MxA protein staining. These results show that there were significantly higher TLR7 and lower TLR3 and TLR9 mRNA expression in early stage of BA than in CC. MxA mRNA expression was also significantly higher in early stage of BA and in CC than in late stage of BA. Immunoreactive TLR7 and MxA staining was higher in early stage of BA than in late stage of BA, NH and CC, which was associated with significantly higher IL-8 mRNA expression in BA than in CC. The results implicate involvement of TLRs, particularly TLR7, and type 1 specific interferon signaling in the pathogenesis of BA, especially in early stage, which is associated with upregulation of inflammatory cytokines IL-8.

Temporal trends in early clinical outcomes and health care resource utilization for liver transplantation in the United States

INTRODUCTION

Procedures such as liver transplantation, which entail large costs while benefiting only a small percentage of the population, are being increasingly scrutinized by third-party payors. The purpose of our study was to conduct a longitudinal analysis of the early clinical outcomes and health care resource utilization for liver transplantation in the United States.

METHODS

The Nationwide Inpatient Sample database was used to conduct a longitudinal analysis of the clinical outcome and resource utilization data for liver transplantation procedures in adult recipients performed in the United States over three time periods (Period I: 1988-1993; Period II: 1994-1998: Period III: 1999-2003).

RESULTS

Compared to Period I, adult liver transplant recipients were more likely to be male, older, and non-White in Period III. Recipients were more likely to have at least one major comorbidity preoperatively than in Period I. The in-hospital mortality rate after liver transplantation decreased significantly from Period I to Period III, but the major intraoperative and postoperative complication rates increased over the same time period. Mean length of hospital stay decreased over the 15-year period, but the percentage of patients with a non-routine discharge status increased.

CONCLUSION

Our findings indicate that the rate of postoperative complications and non-routine discharges after liver transplantation is increasing. However, these negative changes in the cost-outcomes relationship for liver transplantation are balanced by improving postoperative survival rates and reductions in the length of hospital stay.

Fatores de risco para a falência do transplante ortotópico de fígado no Rio Grande do Sul, Brasil

Fatores de risco para falência do transplante ortotópico de fígado com doador cadáver foram investigados em estudo longitudinal retrospectivo com informações da Central Estadual de Transplantes e prontuário clínico de residentes no Rio Grande do Sul, Brasil, submetidos, após os 15 anos de idade, pela primeira vez, a esse transplante de janeiro de 1999 a julho de 2003 (n = 313). Houve 13% de falências (n = 41) no primeiro mês, 11% (n = 34) de 2 a 12 meses e 5% (n = 17) após esse período; 88% das falências resultaram em óbito, 12%, em retransplante. Nos modelos multivariados, a taxa de falência foi maior para renda familiar menor que dez salários-mínimos, idade maior que 45 anos, cor não branca, mau estado geral à época do transplante e doador com 56 anos ou mais. Gênero feminino evidenciou efeito apenas no modelo bruto, perdendo o efeito no modelo multivariado. Apoio social, com complementação de renda e pronto diagnóstico com ingresso na lista em boas condições clínicas, pode favorecer o sucesso do transplante hepático.

Development and validation of a model predicting graft survival after liver transplantation

This study aimed to develop and validate a comprehensive model that predicts survival after liver transplantation based on pretransplant donor and recipient characteristics. Complete data were available from the United Network for Organ Sharing for 20,301 persons who underwent liver transplantation in the United States between 1994 and 2003. Proportional-hazards regression was used to identify the donor and recipient characteristics that best predicted survival and incorporate these characteristics in a multivariate model. A data-splitting approach was used to compare survival predicted by the model to the observed survival in samples not used in the derivation of the model. A model was derived using 4 donor characteristics (age, cold ischemia time, gender, and race/ethnicity) and 9 recipient characteristics (age, body max index, model for end-stage liver disease score, United Network for Organ Sharing priority status, gender, race/ethnicity, diabetes mellitus, cause of liver disease, and serum albumin) that adequately predicted survival after liver transplantation in patients without hepatitis C virus, and a slightly different model was used for patients with hepatitis C virus. The models illustrate that variations in both pretransplant donor and recipient characteristics have a large effect on posttransplant survival. In conclusion, the models presented here can be used to derive scores that are proportional to the excess risk of graft loss after liver transplantation for potential donors, recipients, or donor/recipient combinations. The models may be used to inform liver transplant candidates and their doctors what posttransplant survival would be expected when a given donor is offered and may be particularly helpful for marginal or high-risk donors.

Prospective evaluation of vascular complications after liver transplantation: comparison of conventional and microbubble contrast-enhanced US

PURPOSE

To prospectively compare diagnostic performance of conventional Doppler ultrasonography (US) and microbubble contrast material-enhanced US for assessment of vascular complications after liver transplantation, with clinical follow-up or angiography as reference standard.

MATERIALS AND METHODS

This study was approved by institutional review board and was HIPAA compliant. Written informed consent was obtained. Seventy-two patients (49 men, 23 women; average age, 52.3 years) were included in this study. Patients who had undergone liver transplantation underwent conventional color Doppler and contrast-enhanced US of the liver. Quality of hepatic artery (HA) and portal vein (PV) visualization, contrast material arrival time, and time for complete evaluation of vasculature were compared for both techniques. McNemar test was used to compare vascular flow visualization scores; Student t test was used to compare mean study times with both techniques. Patients without HA flow at Doppler US underwent angiography; those with flow were followed up clinically. McNemar test was used to compare sensitivity of both techniques.

RESULTS

Contrast-enhanced US helped significantly improve flow visualization in hepatic vessels (P < .001). Mean contrast material arrival time was 13.7 seconds +/- 3.8 (standard deviation) in proper HA and 20.7 seconds +/- 6.3 in PV. Mean study time decreased from 27.4 minutes +/- 13.9 to 9.3 minutes +/- 4.5 (P < .01). Doppler US failed to depict HA flow in eight patients; contrast-enhanced US showed flow in six and no flow in two of these patients. Follow-up results confirmed contrast-enhanced US findings. Sensitivity, specificity, and accuracy for Doppler US were 91.3%, 100%, and 91.5%, respectively. Sensitivity, specificity, and accuracy of contrast-enhanced US were all 100%. Sensitivity and accuracy values of the two techniques were significantly different (P < .014); there was no significant difference in specificity (P > .99)

CONCLUSION

Contrast-enhanced US helped improve flow visualization in the HA and PV, decrease scanning time, and correctly differentiate between thrombosis and a patent artery in patients without HA flow at conventional Doppler US.

Functional analysis of encapsulated hepatic progenitor cells

A major challenge in developing therapies based on progenitor or stem cell populations (from sources other than bone marrow) involves developing a mode to deliver these cells in a manner that optimizes their viability, engraftment, proliferation, and differentiation. We have previously isolated a hepatic progenitor cell (HPC) population from adult liver tissue that differentiates into hepatic and biliary cell subtypes. We postulated that, using electrostatic encapsulation, we could reproducibly generate an ex vivo environment for the HPCs. We also theorized that this approach would foster cellular viability and function of the progenitor cell population. Using this encapsulation process, we consistently produced beads with uniform diameters between 200 and 700 microm. In vitro analysis of the encapsulated beads demonstrated extended periods of viability and function based on albumin production, urea metabolism, and glycogen storage. In conclusion, HPC encapsulation fosters the subsequent differentiation of HPCs into functional cells while maintaining their viability in long-term culture. These results demonstrate the efficacy of this method using somatic-derived progenitor cell populations and pave the way for clinical therapies.