The NIDDK liver transplantation database

Anesthesia Management of Liver Transplantation

Anesthesia for liver transplantation pertains to a continuum of critical care of patients with end-stage liver disease. Hence, anesthesiologists, armed with a comprehensive understanding of pathophysiology and physiologic effects of liver transplantation on recipients, are expected to maintain homeostasis of all organ function. Specifically, patients with fulminant hepatic failure develop significant changes in cerebral function, and cerebral perfusion is maintained by monitoring cerebral blood flow and cerebral metabolic rate of oxygen, and intracranial pressure. Hyperdynamic circulation is challenged by the postreperfusion syndrome, which may lead to cardiovascular collapse. The goal of circulatory support is to maintain tissue perfusion via optimal preload, contractility, and heart rate using the guidance of right-heart catheterization and transesophageal echocardiography. Portopulmonary hypertension and hepatopulmonary syndrome have high morbidity and mortality, and they should be properly evaluated preoperatively. Major bleeding is a common occurrence, and euvolemia is maintained using a rapid infusion device. Pre-existing coagulopathy is compounded by dilution, fibrinolysis, heparin effect, and excessive activation. It is treated using selective component or pharmacologic therapy based on the viscoelastic properties of whole blood. Hypocalcemia and hyperkalemia from massive transfusion, lack of hepatic function, and the postreperfusion syndrome should be aggressively treated. Close communication between all parties involved in liver transplantation is also equally valuable in achieving a successful outcome.

Risk factors for acute kidney injury following orthotopic liver transplantation: the impact of changes in renal function while patients await transplantation

Background

Acute kidney injury (AKI) occurs commonly in the setting of orthotopic liver transplantation (OLT). To date, the correlation between AKI post-OLT and pre-operative changes in renal function has not been rigorously examined.

Methods

To determine the impact of pre-OLT changes in renal function on AKI post-OLT, as well as to identify risk factors for AKI, we analyzed the prospectively maintained NIDDK Liver Transplantation Database, which includes patients who received their first OLT between April 15, 1990, and June 30, 1994. We used the AKI Network definition of AKI.

Results

Surprisingly, univariate analysis revealed that worsening renal function while awaiting OLT was protective to the development of AKI post-OLT. Independent predictors of AKI were increased body mass index, increased Childs-Pugh-Turcott score, decreased urine output during cross-clamp, improved renal function while awaiting OLT, increased post-operative stroke volume, non-Caucasian race, and post-operative use of tacrolimus.

Conclusions

The correlation between improving renal function pre-OLT and AKI post-OLT may represent true protection (via ischemic pre-conditioning) or, alternatively, a masking of milder forms of AKI (via improved renal perfusion through correction of the cirrhotic milieu). These results highlight the complex interaction between liver and kidney disease, and suggest that not only the etiology but also the course of pre-OLT renal dysfunction may be a critical determinant of renal function post-OLT.

In a 12-year study, sustainability of quality of life benefits after liver transplantation varies with pretransplantation diagnosis

BACKGROUND & AIMS

As life-extending benefits of liver transplantation (LTX) are realized, the focus of improving outcomes after LTX transitioned from merely extending quantity of life to improving quality of life (QOL). Numerous cross-sectional studies have shown that QOL improves within 1 year after LTX; however, the long-term prospective pattern of QOL is not known. We assessed the sustainability of early QOL benefits after LTX.

METHODS

Patients who underwent LTX (n = 381) were followed for 12 years. We collected clinical information, survival data, and data on 5 QOL domains: physical distress (PHY), psychological distress (PSY), social/role function (SRF), personal function (PF), and general health perception (GHP). Mixed model analysis was used to determine whether initial gains in QOL were sustained long term. Outcomes were analyzed according to the primary liver diagnosis.

RESULTS

After 12 years, liver recipients had marked declines in PHY (P < .001), SRF (P = .006), and GHP (P < .001) scores, whereas improvements in PSY (P = .09) and PF (P = .09) were sustained. Women had worse outcomes in PHY and PF than men. Patients with autoimmune disease had decreased QOL PHY, SRF, PF, and GHP domains. Patients with alcoholic liver disease and hepatitis C initially had lower QOL in all domains, with the greatest decreases in PHY (P < .001) and PF (P = .03).

CONCLUSIONS

Although QOL improves within 1 year after patients receive liver transplants, not all groups of patients achieve or sustain the same level of QOL for 12 years. QOL decreases with time in most areas. Efforts should be made to improve QOL and function in the initial recovery period in liver transplant recipients.

Evolution of causes and risk factors for mortality post-liver transplant: results of the NIDDK long-term follow-up study

Although mortality rates following liver transplantation (LT) are well described, there is a lack of detailed, prospective studies determining patterns of and risk factors for long-term mortality. We analyzed the multicenter, prospectively obtained The National Institute of Diabetes and Digestive and Kidney Diseases LT Database of 798 transplant recipients from 1990 to 1994 (follow-up 2003). Overall, 327 recipients died. Causes of death >1 year: 28% hepatic, 22% malignancy, 11% cardiovascular, 9% infection, 6% renal failure. Renal-related death increased dramatically over time. Risk factors for death >1 year (univariate): male gender, age/decade, pre-LT diabetes, post-LT diabetes, post-LT hypertension, post-LT renal insufficiency, retransplantation >1 year, pre-LT malignancy, alcoholic disease (ALD) and metabolic liver disease, with similar risks noted for death >5 years. Hepatitis C, retransplantation, post-LT diabetes, hypertension and renal insufficiency were significant risk factors for liver-related death. Cardiac deaths associated with age, male gender, ALD, cryptogenic disease, pre-LT hypertension and post-LT renal insufficiency. In summary, the leading causes of late deaths after transplant were graft failure, malignancy, cardiovascular disease and renal failure. Older age, diabetes and renal insufficiency identified patients at highest risk of poor survival overall. Diligent management of modifiable post-LT factors including diabetes, hypertension and renal insufficiency may impact long-term mortality.

Long-term probability of and mortality from de novo malignancy after liver transplantation

BACKGROUND & AIMS

Information about malignancies that arise in patients after liver transplantation comes from volunteer registry databases and single-center retrospective studies. We analyzed a multicenter, prospectively obtained database to assess the probabilities of and risk factors for de novo malignancies in patients after liver transplantation.

METHODS

We analyzed the National Institute of Diabetes and Digestive and Kidney Diseases' liver transplantation database of 798 adults who received transplants from April 1990 to June 1994 and long-term follow-up data through January 2003. In this patient population, 171 adult patients developed 271 de novo malignancies. Of these malignancies, 147 were skin-related, 29 were hematologic, and 95 were solid organ cancers; we focused on nonskin malignancies.

RESULTS

The probability of developing any nonskin malignancy was highest in patients with primary sclerosing cholangitis (PSC; 22% at 10 years) or alcohol-related liver disease (ALD; 18% at 10 years); all other diagnoses had a 10% probability. Multivariate analysis indicated that increased age by decade (hazard ratio [HR] = 1.33, P = .01), a history of smoking (HR = 1.6, P = .046), PSC (HR = 2.5, P = .001), and ALD (HR = 2.1, P = .01) were associated with development of solid malignancies after liver transplantation. The probabilities of death after diagnosis of hematologic and solid malignancy were 44.0% and 38.0% at 1 year and 57.6% and 53.1% at 5 years, respectively.

CONCLUSIONS

De novo malignancy primarily affects patients with PSC or ALD, compared to other transplant recipients, with a significant impact on long-term survival.

Immunogenetic susceptibility to diabetes mellitus in patients with liver disease

BACKGROUND/AIM

Genetic, environmental, metabolic and infectious influences, such as hepatitis C virus (HCV) infection, are thought to impact on the development of diabetes in patients with liver disease. As specific human leucocyte antigen (HLA) alleles provide the major genetic risk factors for type 1 diabetes, our aim was to investigate whether HLA class I and II alleles constitute additional risk factors for diabetes in patients with liver disease.

METHODS

We evaluated two independent databases of 193 and 728 adult patients with chronic liver disease for the diagnosis of diabetes and the presence of specific HLA subtypes.

RESULTS

In each database, 24 and 19% of patients met criteria for diabetes. In the first database, specific class I and II alleles were observed more frequently in diabetics compared with non-diabetics: Cw7 (50 vs. 32%, P=0.04), DR51 (17 vs. 3%P=0.003) and DQ6 (37 vs. 18%, P=0.02). In the second database, DQ6 was observed in 16% of diabetics vs. 8% of non-diabetics (P=0.04). The DR2-DR51-DQ6 haplotype was higher in patients with diabetes in both databases (22 vs.7%, P=0.02 and 12 vs. 5%, P=0.02). In a subgroup analysis of patients with HCV infection, increased frequencies of Cw7, DR2/DR51, DQ6 and DR2-DR51-DQ6 were also observed to be higher in subjects with diabetes compared with those without diabetes.

CONCLUSIONS

Patients with chronic liver disease, especially those with HCV infection, have an immunogenetic risk for diabetes characterized by the presence of Cw7, DR51, DQ6 and DR2-DR51-DQ6.

Disparities in liver transplantation before and after introduction of the MELD score

CONTEXT

In February 2002, the allocation system for liver transplantation became based on the Model for End-Stage Liver Disease (MELD) score. Before MELD, black patients were more likely to die or become too sick to undergo liver transplantation compared with white patients. Little information exists regarding sex and access to liver transplantation.

OBJECTIVE

To determine the association between race, sex, and liver transplantation following introduction of the MELD system.

DESIGN, SETTING, AND PATIENTS

A retrospective cohort of black and white patients (> or = 18 years) registered on the United Network for Organ Sharing liver transplantation waiting list between January 1, 1996, and December 31, 2000 (pre-MELD cohort, n = 21 895) and between February 28, 2002, and March 31, 2006 (post-MELD cohort, n = 23 793).

MAIN OUTCOME MEASURES

Association between race, sex, and receipt of a liver transplant. Separate multivariable analyses evaluated cohorts within each period to identify predictors of time to death and the odds of dying or receiving liver transplantation within 3 years of listing. Patients with hepatocellular carcinoma were analyzed separately.

RESULTS

Black patients were younger (mean [SD], 49.2 [10.7] vs 52.4 [9.2] years; P < .001) and sicker (MELD score at listing: median [interquartile range], 16 [12-22] vs 14 [11-19]; P < .001) than white patients on the waiting list for both periods. In the pre-MELD cohort, black patients were more likely to die or become too sick for liver transplantation than white patients (27.0% vs 21.7%) within 3 years of registering on the waiting list (odds ratio [OR], 1.51; 95% confidence interval (CI), 1.15-1.98; P = .003). In the post-MELD cohort, black race was no longer associated with increased likelihood of death or becoming too sick for liver transplantation (26.5% vs 22.0%, respectively; OR, 0.96; 95% CI, 0.74-1.26; P = .76). Black patients were also less likely to receive a liver transplant than white patients within 3 years of registering on the waiting list pre-MELD (61.6% vs 66.9%; OR, 0.75; 95% CI, 0.59-0.97; P = .03), whereas post-MELD, race was no longer significantly associated with receipt of a liver transplant (47.5% vs 45.5%, respectively; OR, 1.04; 95% CI, 0.84-1.28; P = .75). Women were more likely than men to die or become too sick for liver transplantation post-MELD (23.7% vs 21.4%; OR, 1.30; 95% CI, 1.08-1.47; P = .003) vs pre-MELD (22.4% vs 21.9%; OR, 1.08; 95% CI, 0.91-1.26; P = .37). Similarly, women were less likely than men to receive a liver transplant within 3 years both pre-MELD (64.8% vs 67.6%; OR, 0.80; 95% CI, 0.70-0.92; P = .002) and post-MELD (39.9% vs 48.7%; OR, 0.70; 95% CI, 0.62-0.79; P < .001).

CONCLUSION

Following introduction of the MELD score to the liver transplantation allocation system, race was no longer associated with receipt of a liver transplant or death on the waiting list, but disparities based on sex remain.

The impact of obesity on long-term outcomes in liver transplant recipients-results of the NIDDK liver transplant database

The impact of obesity on outcomes following liver transplantation has been difficult to determine, in part due to the confounding effects of ascites on BMI. We evaluated the impact of pretransplant recipient obesity on outcomes following liver transplantation using the NIDDK Liver Transplantation Database. Pretransplant BMI, corrected for ascites, was categorized as underweight (BMI <18 kg/m(2)), normal weight (BMI 18-25 kg/m(2)), overweight (BMI 25.1-30 kg/m(2)), Class I obese (BMI 30.1-35 kg/m(2)), Class II obese (BMI 35.1-40 kg/m(2)) and Class III obese (BMI >40 kg/m(2)). Primary outcomes were patient and graft survival. Secondary outcomes included days in hospital and days in ICU. Data from 704 adult liver transplant recipients from the NIDDK LTD and a further 609 patients from the Mayo Clinic were analyzed. Early and late patient and graft survival was similar across all BMI categories. Correcting for ascites volume resulted in 11-20% of patients moving into a lower BMI classification. The relative risk for mortality increased by 7% for each liter of ascites removed. We conclude that corrected BMI is not independently predictive of patient or graft survival. Obesity, within the ranges observed in this study, should not be considered to be a contraindication to liver transplantation in the absence of other relative contraindications.

Racial disparities in the management of hospitalized patients with cirrhosis and complications of portal hypertension: a national study

Having complications of portal hypertension is a harbinger of decompensated cirrhosis and warrants consideration for liver transplantation (LT). Racial disparities in LT have been reported. We sought to characterize disparities in the performing of surgical and endoscopic procedures among hospitalized patients with complications of portal hypertension. We queried the Nationwide Inpatient Sample from 1998 to 2003 to identify patients with cirrhosis and complications of portal hypertension. Logistic regression controlling for confounders was used to evaluate race as a predictor of undergoing a portosystemic shunt and LT and of dying in the hospital. Compared to whites, the adjusted odds ratios of receiving a portosystemic shunt were 0.37 (95% CI: 0.27-0.51) and 0.69 (95% CI: 0.54-0.88) for African Americans (AAs) and Hispanics, respectively. AAs with variceal bleeding were more likely to have endoscopic variceal hemostasis delayed more than 24 hours after admission than were whites (OR 1.6; 95% CI: 1.2-2.1). The adjusted odds ratios of undergoing LT were 0.32 (95% CI:0.20-0.52) and 0.46 (95% CI: 0.25-0.83) for AAs and Hispanics, respectively. Compared to whites, AAs experienced higher in-hospital mortality (OR 1.12; 95% CI: 1.01-1.24), whereas Hispanics had a lower risk of death (OR 0.83; 95% CI: 0.75-0.92). Among variceal bleeders, the odds ratio of death for AAs was 1.7 (95% CI: 1.2-2.4) compared to whites.

CONCLUSION

AAs and Hispanics hospitalized for complications of portal hypertension were less likely to undergo a palliative shunt or LT than whites, which may contribute to the higher in-hospital mortality of AAs. Further studies are warranted to elucidate the mechanisms of these exploratory findings.

The problem of disguised missing data

Missing data is a well-recognized problem in large datasets, widely discussed in the statistics and data analysis literature. Many programming environments provide explicit codes for missing data, but these are not standardized and are not always used. This lack of standardization is one of the leading causes of the subtle problem of disguised missing data , in which unknown, inapplicable, or otherwise nonspecified responses are encoded as valid data values. Following a brief overview of the problem of explicitly coded missing data, this paper discusses sources, consequences, and detection of disguised missing data, including two real-world examples. As the first of these examples illustrates, the consequences of disguised missing data can be quite serious. The key to its detection lies in first, recognizing disguised missing data as a possibility and second, finding a sufficiently informative view of the data to reveal its presence.

Post-transplantation growth among pediatric recipients of liver transplantation

Improving a patient's quality-of-life (QOL) post-liver transplantation is of great importance. An aspect of improved QOL is the restoration of normal growth patterns in pediatric patients. To describe the post-transplantation growth patterns of 72 children included in the National Institute of Diabetes and Digestive and Kidney Diseases - Liver Transplantation Database (NIDDK-LTD), multilevel models were used, according to which children who waited more than a year for transplantation were smaller, compared with age and sex matched peers, at transplantation than children who waited less than a year while children who were growth retarded at transplantation experienced a larger yearly comparison height increase than children who were not growth retarded. The analysis also showed that boys older than 2 yr and younger than 13 yr at transplantation and girls older than 2 yr and younger than 11 yr at transplantation were significantly less growth retarded at transplantation than boys and girls under the age of 2 yr at transplantation.

Long-term results and modeling to predict outcomes in recipients with HCV infection: results of the NIDDK liver transplantation database

Hepatitis C virus (HCV)-associated liver disease is the most common indication for liver transplantation (LT). There are, however, no long-term (>5 year) studies of comparative outcomes for recipients with HCV infection, and no models capable of identifying recipients with HCV infection at greatest risk for adverse outcomes. We prospectively determined: 1) long-term outcomes, and 2) whether pretransplant patient or donor variables can be used to predict death and/or graft loss in recipients with HCV infection. A total of 165 HCV-infected recipients were eligible for this study. Pretransplant donor and recipient characteristics and patient and graft survival data were prospectively collected. Model building for outcomes was carried out using logistic regression. Receiver operating characteristic curves for different models were created and compared. Median follow-up was 8.5 years. Adjusted 10 year graft survival was 64% for recipients with HCV infection and 51% for uninfected recipients. A model incorporating pretransplant HCV ribonucleic acid (RNA), cytomegalovirus immunoglobulin (CMV IgG) serostatus, creatinine, bilirubin, prothrombin time international ratio (INR), recipient age, and donor age was developed to identify recipients at greatest risk of short-term mortality or graft loss (area under receiver operating characteristic curve = .83) In conclusion, long-term outcomes following LT for recipients with HCV infection are comparable to those for recipients undergoing LT for other indications. HCV-infected recipients at greatest risk for short-term mortality and graft loss can be identified using several readily identifiable pretransplant variables. Long-term death and graft loss specifically secondary to recurrence of HCV appears, however, to be determined primarily by factors other than those included in this analysis.

Disparity in use of orthotopic liver transplantation among blacks and whites

Orthotopic liver transplantation (OLT) is the best treatment for end-stage liver disease. Limited data exist on the access of minorities to OLT. The aim of this study was to determine whether disparities exist among black and white OLT patients. Data were collected from the United Network for Organ Sharing on black and white 18-70 year-old OLT waiting list registrants (n = 29,013) and OLT recipients (n = 15,805) between 1994 and 1998. Standardized transplant ratios were generated by comparing the racial distribution of OLT patients with the US population. Demographic and clinical characteristics of OLT registrants were compared by race. Multivariate analyses were performed to identify predictors of time to OLT and the likelihood of dying or receiving OLT within 4 years, controlling for severity of illness and other factors. The standardized transplant ratio for black OLT recipients (0.65) was significantly lower than the standardized transplant ratio for white OLT recipients (1.05). Blacks were younger and sicker than whites. After adjustment for severity and other factors, time to OLT among recipients did not differ by race (P >.05). Blacks were more likely to die or become too ill for OLT while waiting (P <.001). Blacks were less likely to receive OLT within 4 years (P <.001). In conclusion, adult blacks were underrepresented among OLT patients. Although waiting times were similar once listed, black race affected outcomes while awaiting OLT. The process of referral and evaluation for OLT should be investigated further.

Surgical site infections following pediatric liver transplantation: risks and costs

PURPOSE

Infectious complications following orthotopic liver transplantation (OLT) represent a significant cause of morbidity and mortality in both adults and children. In adults, surgical site infections complicating OLT have been shown to significantly increase resource utilization, but their impact in children has not been studied. In this study we identify risk factors for surgical site infections in children undergoing primary OLT for end-stage liver disease and estimate their impact on patient survival, graft survival, length of stay, and charges.

METHODS

All pediatric liver transplants (n = 77) less than 16 years of age from the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) Liver Transplantation Database were included in the analysis. Surgical site infections (n = 25) were defined as wound infections, abdominal abscesses, and bacterial or fungal infections of the liver, intestine, or peritoneum during the initial transplant admission. Risk of infection was estimated using logistic regression, survival rates were estimated using the Kaplan-Meier method, and length of stay and charges were compared using Student's t-test. Multivariate analysis of charges was performed using linear regression.

RESULTS

Of the 77 patients, 25 (32.5%) developed a surgical site infection. Several factors were associated with increased risk of infections, including a leak at the biliary anastomosis (odds ratio [OR] 115, P = 0.003), preoperative white blood cell count (OR = 1.28, P = 0.009), surgery > 7 h (OR = 15.0, P = 0.011), HLA mismatches (OR = 6.0, P = 0.03), and female gender (OR = 8.0, P = 0.038). Surgical site infections did not significantly decrease either patient survival or graft survival, and increased hospital stay by an average of 21 days (P = 0.14). After controlling for other factors, patients who developed surgical site infections incurred on average $132,507 (P = 0.03) more in charges than patients who did not develop infections.

CONCLUSIONS

Surgical site infections in pediatric patients following liver transplantation are significantly influenced by surgical technique and endogenous patient characteristics. Though survival outcomes are not different, the development of such infections has significant implications for resource utilization in the care of these patients.

Completeness of data entry in three cancer surgery databases

AIMS

Clinical databases are regularly used for audit and research purposes. The accuracy of data input is critical to the value of these tools, but little is known about the factors which influence the completeness of data recording. The aim of this study was to evaluate the influences affecting completeness of data recording in computerized clinical databases of cancer treatment.

METHODS

Data omission rates in three databases dealing with management of breast, colorectal and gastro-oesophageal cancers were calculated. The effects of (a) type of record; (b) nature of data and (c) training required to interpret data were evaluated by univariate and multivariate analyses.

RESULTS

The overall data omission rate was 21.9% (upper GI 27.6%, breast 19.6%, colorectal 32.7%, P=0.13). For different categories of data, omission rates varied from 0% to 55%. Fields requiring a 'text field' or 'numerical' entry, or containing demographic data, data required for the process of care or data which required no interpretation were associated with low omission rates. Clinical data, and fields requiring a 'yes/no' response were associated with high omission rates (45 and 48% respectively). Clinical data and data relating to patient demographic details were independently associated with high and low omission rates respectively (odds ratios for significant missing data 86.9 and 1 respectively).

CONCLUSION

Clinical data are poorly captured by current cancer surgery databases. Reasons for the poor completion of fields requiring input by clinical staff, particularly availability of time and training, and prioritization of work, should be addressed. Re-design of databases to ensure that data entry is simple and unambiguous may improve accuracy.

Real-time monitoring of acute liver-allograft rejection using the Banff schema

BACKGROUND

The Banff schema is the internationally accepted standard for grading acute liver-allograft rejection, but it has not been prospectively tested.

METHODS

Complete Banff grading was prospectively applied to 2,038 liver-allograft biopsies from 901 adult tacrolimus-treated primary hepatic allograft recipients between August 1995 and September 2001. Histopathologic data was melded with demographic, clinical, and laboratory data into a database on an ongoing basis using locally developed software.

RESULTS

Acute rejection developed in 575 of 901 (64%) patients and the worst grade was mild in 422 of 575 (73%). At least one episode of moderate or severe acute rejection developed in 153 of 901 (17%) patients and most episodes, irrespective of severity, occurred within the first year after transplantation. Patients with moderate or severe acute rejection showed higher alanine aminotransferase (P =0.007) and aspartate aminotransferase ( P=0.07) levels and were more likely to develop perivenular fibrosis on follow-up biopsies (P =0.001) and graft failure from acute or chronic rejection ( P=0.004) than those with mild rejection. Regardless of severity, 80% of patients with acute rejection did not develop significant fibrosis in follow-up biopsies, and graft failure from acute or chronic rejection occurred in only 11 of 901 (1%) allografts.

CONCLUSIONS

Most acute-rejection episodes are mild and do not lead to clinically significant architectural sequelae. When tested prospectively under real-life and -time conditions, the Banff schema can be used to identify those few patients who are potentially at risk for more significant problems. Creation, capture, and integration of non-free text, or "digital," pathology data can be used to prospectively conduct outcomes-based research in transplantation.

The economic impact of preservation time in cadaveric liver transplantation

There has been considerable recent debate concerning the reconfiguration of the cadaveric liver allocation system with the intent to allocate livers to more severely ill patients over greater distances. We sought to assess the economic implications of longer preservation times in cadaveric liver transplantation that may be seen in a restructured allocation system. A total of 683 patients with nonfulminant liver disease, aged 16 years or older, receiving a cadaveric donor liver as their only transplant, were drawn from a prospective cohort of patients who received transplants between January 1991 and July 1994 at the University of California, San Francisco, the Mayo Clinic, Rochester, Minnesota, or the University of Nebraska, Omaha. The primary outcome measure was standardized hospitalization resource utilization from the day of transplantation through discharge. Secondary outcome measures included 2-year patient survival, and 2-year retransplantation rates. Results indicated that each 1-h increase in preservation time was associated with a 1.4% increase in standardized hospital resource utilization (p = 0.014). The effects on 2-year patient survival and retransplantation rates were not measurably affected by an increase in preservation time. We conclude that policies that increase preservation time may be expected to increase the cost of liver transplantation.

The effect of surgical site infections on outcomes and resource utilization after liver transplantation

BACKGROUND

Although postoperative infections have a significant impact on morbidity and mortality after orthotopic liver transplantation (OLT), less is known about their economic implications. In this study, we sought to identify risk factors and estimate the impact of surgical site infections on 1-year mortality, graft survival, and resource utilization after OLT.

METHODS

We studied 777 first, single-organ liver transplant recipients from the National Institute of Diabetes and Digestive and Kidney Diseases Liver Transplantation Database. Surgical site infections (n = 292, 37.8%) were defined as bacterial or fungal infections of the liver, intestine, biliary tract, surgical wound, or peritoneum within 1 year of transplantation. A subset of these (n = 159) occurred during the transplant hospitalization and were used to estimate excess charges associated with surgical site infections.

RESULTS

Leaks in the choledochojejunostomy (odds ratio [OR] = 7.1, P =.001) and choledochocholedochostomy (OR = 2.5, P =.002), extended operation duration in hours (OR = 1.2, P =.002), serum albumin levels in grams per liters (OR = 0.71, P =.009), ascites (OR = 1.43, P =.037), and administration of OKT3 within 7 days (OR = 1.49, P =.039) significantly increased risk of infection. Surgical site infections did not significantly increase 1-year mortality (88.5% vs 91.5%, P =.19) but significantly increased 1-year graft loss (79.8% vs 86.5%, P =.022). Patients with surgical site infections incurred approximately 24 extra hospital days and $159,967 in excess charges (P =.0001). Multivariate analysis reduced the estimate of excess charges to $131,276 (P =.0001).

CONCLUSIONS

Liver transplant recipients who develop surgical site infection have significantly higher resource utilization requirements than those who do not. These results imply substantial returns to preventative efforts directed at surgical site infections in patients undergoing OLT.

Predicting clinical and economic outcomes after liver transplantation using the Mayo primary sclerosing cholangitis model and Child-Pugh score. National Institutes of Diabetes and Digestive and Kidney Diseases Liver Transplantation Database Group

Issues in the selection and timing of liver transplantation for primary sclerosing cholangitis (PSC) remain controversial. Although the Child-Pugh classification (CP) score and Mayo PSC model have similar abilities to estimate pretransplantation survival, a comparison of these 2 scores in predicting survival after liver transplantation has not been conducted. The aim of this study is to compare the Mayo PSC model and CP score in predicting patient survival and related economic outcomes after liver transplantation. Data from 128 patients with PSC, identified from the NIDDK database, were used to calculate patient-specific Mayo PSC and CP scores before transplantation. Levels reflecting a poor outcome were defined a priori. Receiver operating characteristic (ROC) curves and regression methods (Cox proportional hazards and linear regression models) were used to assess the relationship between these 2 scores and 5 post liver transplantation outcome measures. CP score was found to be a significantly (P <.05) better predictor of death 4 months or less after liver transplantation than: (a) length of hospital stay >21 days (or death before discharge) and (b) resource utilization >200,000 units (measured by area under the ROC curve). The Cox model identified statistically significant (P <.05) associations between CP score and each outcome after adjusting for the Mayo PSC risk score. Similar results were not observed for the Mayo PSC model when adjusted for CP score. Among patients with PSC undergoing liver transplantation, CP score was a better overall predictor of both survival and economic resource utilization compared with the Mayo PSC model.

Chronic liver allograft rejection in a population treated primarily with tacrolimus as baseline immunosuppression: long-term follow-up and evaluation of features for histopathological staging

BACKGROUND

Predisposing factors, long-term occurrence, and histopathological changes associated with recovery or progression to allograft failure from chronic rejection (CR) were studied in adult patients treated primarily with tacrolimus.

METHODS

CR cases were identified using stringent criteria applied to a retrospective review of computerized clinicopathological data and slides.

RESULTS

After 1973 days median follow-up, 35 (3.3%) of 1049 primary liver allograft recipients first developed CR between 16 and 2532 (median 242) days. The most significant risk factors for CR were the number (P<0.001) and histological severity (P<0.005) of acute rejection episodes and donor age >40 years (P<0.03). Other demographic and matching parameters were not associated with CR in this cohort. Ten patients died with, but not of, CR. Eight required retransplantation because of CR at a median of 268 days. Ten resolved either histologically or by normalization of liver injury tests over a median of 548 days. CR persisted for 340 to 2116 days in the remaining seven patients. More extensive bile duct loss (P<0.01), smallarterial loss (P<0.03), foam cell clusters (P<0.01) and higher total bilirubin (P<0.02) and aspartate aminotransferase (P<0.03) were associated with allograft failure from CR.

CONCLUSIONS

Early chronic liver allograft rejection is potentially reversible and a combination of histological, clinical, and laboratory data can be used to stage CR. Unique immunological and regenerative properties of liver allografts, which lead to a low incidence and reversibility of early CR, can provide insights into transplantation biology.

Cholangiocarcinoma in patients with primary sclerosing cholangitis: a multicenter case-control study

Patients with primary sclerosing cholangitis (PSC) have a significantly increased risk of developing cholangiocarcinoma (CCA). Risk factors for developing such a complication are not well defined. We conducted a multicenter, case-control study to determine the risk factors and possible predictors for CCA in patients with PSC. The demographic, clinical, and laboratory features of 26 PSC patients with CCA diagnosed over a 7-year period at eight academic centers were compared with 87 patients with PSC but no CCA (controls). There was no statistically significant difference in demographics, smoking, signs or symptoms or complications of PSC, indices of disease severity (Mayo Risk score or Child-Pugh score), frequency or duration or complications of inflammatory bowel disease (IBD), frequency of biliary surgery, or therapeutic endoscopy between the two groups. Alcohol consumption was significantly associated with CCA in patients with PSC (odds ratio: 2.95; 95% CI: 1.04-8.3). Serum carbohydrate antigen 19-9 (CA 19-9) was significantly higher in patients with CCA than those without (177 +/- 89 and 61 +/- 58 U/mL, respectively; P =.002). A serum CA 19-9 level > 100 U/mL had 75% sensitivity and 80% specificity in identifying PSC patients with CCA. In conclusion, alcohol consumption was a risk factor for having CCA in PSC patients. The indices of severity of liver disease were not associated with CCA in patients with PSC. Serum CA 19-9 appeared to have good ability to discriminate PSC patients with and without CCA.

Analysis of the reversibility of chronic liver allograft rejection implications for a staging schema

In contrast to all other vascularized organ allografts, chronic rejection (CR) of the liver is potentially reversible. We therefore studied demographic, perioperative, biochemical, and histologic features associated with reversibility or progression to graft failure. Using very stringent clinical and histological criteria, we identified a subgroup of 23 of 916 patients receiving primary liver allografts with CR from the Liver Transplantation Database. Of these, 13 experienced graft failure as a result of CR, and 10 patients recovered to normal histology or liver injury test results. Male-to-female sex mismatch (p = 0.07), younger recipient age (p = 0.09), younger donor age (p = 0.06), white-to-white race match (p = 0.09), primary diagnosis of biliary atresia (p = 0.02), and cold ischemia time of more than 12 hours (p = 0.02) were associated with graft failure. Patients who eventually recovered from CR were more likely to have acute rejection within the first 2 weeks (70% vs 23%; p = 0.04), had a higher number of acute rejection episodes (p = 0.08), and were more likely to have been treated with OKT3 (90% vs 46%, p = 0.07). Although overlap existed in the histopathologic findings between the patients whose grafts failed and those who recovered, those patients who developed bile duct loss in more than 50% of the portal tracts (p < 0.01), severe (bridging) perivenular fibrosis (p = 0.05), and the presence of foam cell clusters (p = 0.06) were more likely to require retransplantation. In contrast to other solid organ allografts, CR of the liver is not an irreversible process. These findings can be used to understand the evolution of CR and to design a biologically correct and clinically relevant staging system.

Determination of hepatitis C virus genotype by direct sequence analysis of products generated with the Amplicor HCV test

Consistent with other members of the family Flaviviridae, hepatitis C virus (HCV) demonstrates a high degree of sequence variation throughout the coding regions of its genome. However, there is a high degree of sequence conservation found within the 5' untranslated region (UTR) of the genome, making this region a target of choice for most nucleic acid amplification-based detection assays. In this study, the Amplicor HCV test, a commercially available assay which detects the 5'UTR, was used for the detection of HCV RNA in 669 serum samples obtained from a cohort of liver transplantation patients. Amplification products obtained from the HCV-positive cases were subjected to direct sequencing and genotyping based upon seven phylogenetically informative regions within the 5'UTR. Of the 669 specimens, 416 (62.2%) tested positive for the presence of HCV RNA. Of these, 372 (89.4%) specimens were successfully classified into 11 HCV genotypes and subtypes after computer-assisted analysis of the sequence data. Forty-four (10.6%) of the HCV RNA-positive specimens were not classifiable, the majority corresponding to low-titer specimens as determined by the Chiron Quantiplex HCV RNA 2. 0 assay. Additional comparative studies targeting the NS-5 region of the viral genome generally confirmed the accuracy and sensitivity of the 5'UTR-based classifications, with the exception of the misclassification of a small number of type 1a cases as type 1b. We conclude that although the high sequence conservation within the 5'UTR results in the misclassification of a small number of HCV subtypes, the overall gains of efficiency, the shorter turnaround time, the inclusion of contamination control measures, and the low rate of test failure compared to that of methods based on the NS-5 gene together constitute significant advantages over other techniques.

Recurrent and new hepatitis C virus infection after liver transplantation

Chronic infection with the hepatitis C virus (HCV) is the most common reason for liver transplantation. We examined the results of laboratory tests for HCV on a cohort of patients who received a liver transplant between 1990 and 1994 at three large centers. Seven hundred twenty-two recipients and 604 donors were tested for antibody to HCV (anti-HCV) using a second-generation enzyme-linked immunoassay (EIA-2), followed by recombinant immunoblot (RIBA-2) and HCV RNA confirmation by reverse-transcription polymerase chain reaction (RT-PCR) (with genotyping and viral quantification). Diagnosis of posttransplantation infection required detection of serum HCV RNA that could be genotyped by sequencing or was repeatedly positive despite being unsequenceable. Twenty-five percent of transplantation candidates were seropositive for anti-HCV. Approximately 86% of anti-HCV-positive, 93% of RIBA-positive, and 97% of HCV RNA-positive candidates developed infection after transplantation. Pretransplantation HCV RNA was superior to RIBA-2 for predicting posttransplantation infection. Whereas HCV genotype was identified in nearly all candidates and changed little after transplantation, serum viral levels rose markedly after transplantation. Fifteen donors were either anti-HCV- or HCV RNA-positive. Recipients of grafts from donors with HCV RNA all developed infection, whereas infection was not detected in recipients of grafts from donors with anti-HCV but without detectable HCV RNA. The rate of new infection fell significantly (P =.02) after the introduction of EIA-2 screening of blood. Donor and candidate markers for HCV predict posttransplantation infection.

Predictors of patient and graft survival following liver transplantation for hepatitis C

End-stage liver disease secondary to hepatitis C virus (HCV) infection is the leading indication for liver transplantation in the United States. Recurrence of HCV infection is nearly universal. We studied the patients enrolled in the National Institute of Diabetes and Digestive and Kidney Diseases Liver Transplantation Database to determine whether pretransplantation patient or donor variables could identify a subset of HCV-infected recipients with poor patient survival. Between April 15, 1990, and June 30, 1994, 166 HCV-infected and 509 HCV-negative patients underwent liver transplantation at the participating institutions. Median follow-up was 5.0 years for HCV-infected and 5.2 years for HCV-negative recipients. Pretransplantation donor and recipient characteristics, and patient and graft survival, were prospectively collected and compared. Cumulative patient survival for HCV-infected recipients was similar to that of recipients transplanted for chronic non-B-C hepatitis, or alcoholic and metabolic liver disease, better than that of patients transplanted for malignancy or hepatitis B (P = .02 and P = .003, respectively), and significantly worse than that of patients transplanted for cholestatic liver disease (P = .001). Recipients who had a pretransplantation HCV-RNA titer of > or = 1 x 10(6) vEq/mL had a cumulative 5-year survival of 57% versus 84% for those with HCV-RNA titers of < 1 x 10(6) vEq/mL (P = .0001). Patient and graft survival did not vary with recipient gender, HCV genotype, or induction immunosuppression regimen among the HCV-infected recipients. While long-term patient and graft survival following liver transplantation for end-stage liver disease secondary to HCV are generally comparable with that of most other indications, higher pretransplantation HCV-RNA titers are strongly associated with poor survival among HCV-infected recipients.

Acute hepatic allograft rejection: incidence, risk factors, and impact on outcome

Hepatic allograft rejection remains an important problem following liver transplantation, and, indeed, complications related to the administration of immunosuppressive therapy remain a predominant cause of posttransplantation morbidity and mortality. The Liver Transplantation Database (LTD) was used to study a cohort of 762 consecutive adult liver transplantation recipients and determined the incidence, timing, and risk factors for acute rejection. We also evaluated the impact of histological severity of rejection on the need for additional immunosuppressive therapy and on patient and graft survival. Four hundred ninety (64%) of the 762 adult liver transplantation recipients developed at least one episode of rejection during a median follow-up period of 1,042 days (range, 336-1,896 days), most of which occurred during the first 6 weeks after transplantation. Multivariate analysis revealed that recipient age, serum creatinine, aspartate transaminase (AST) level, presence of edema, donor/recipient HLA-DR mismatch, cold ischemic time, and donor age were independently associated with the time to acute rejection. An interesting observation was that the histological severity of rejection was an important prognosticator: the use of antilymphocyte preparations was higher, and the time to death or retransplantation was shorter, for patients with severe rejection. Findings from this study will assist in decision-making for the use of immunosuppressive regimens and call into question whether complete elimination of all rejection or alloreactivity is a desirable goal in liver transplantation.

Age and liver transplantation: a report of the Liver Transplantation Database

BACKGROUND

The average age of liver transplant recipients has increased steadily during the last decade. The effects of recipient age on outcome of liver transplantation were evaluated in a large prospective database.

METHODS

A total of 735 adult recipients of single-organ liver transplants for nonfulminant liver disease enrolled in a large prospective database between 1990 and 1994 were analyzed for associations of patient age with outcomes. Patients were categorized into two groups: younger being <60 and older being > or = 60 years of age.

RESULTS

Older liver transplant recipients were more likely to be female, white, and have the diagnoses of primary biliary cirrhosis or cryptogenic cirrhosis than younger recipients, who were more likely to have the diagnosis of alcoholic liver disease. Disease severity was similar between the two groups. After transplantation, the durations of stay in the intensive care unit and hospital were longer for older than for younger transplant recipients, but episodes of acute rejection were less frequent. The quality of life at 1 year was similar among older and younger recipients. Patient survival was lower for older than for younger recipients (81% vs. 90% at 1 year; P=0.004), whereas graft survival was not different (80% vs. 85% at 1 year; P=0.163). The excess mortality among older recipients was largely due to nonhepatic causes, including infectious, cardiac, and neurological diseases occurring within 6 months after transplantation.

CONCLUSIONS

Although patient survival was significantly lower among liver transplant recipients above the age of 60 years, the excess mortality was due to nonhepatic, largely age-related problems. The overall success of liver transplantation and improvement in quality of life for older recipients is excellent.

Early allograft dysfunction after liver transplantation: a definition and predictors of outcome. National Institute of Diabetes and Digestive and Kidney Diseases Liver Transplantation Database

BACKGROUND

Poor graft function early after liver transplantation is an important cause of morbidity and mortality. We defined early allograft dysfunction (EAD) using readily available indices of function and identified donor, graft, and pretransplant recipient factors associated with this outcome.

METHODS

This study examined 710 adult recipients of a first, single-organ liver transplantation for non-fulminant liver disease at three United States centers. EAD was defined by the presence of at least one of the following between 2 and 7 days after liver transplantation: serum bilirubin >10 mg/dl, prothrombin time (PT) > or =17 sec, and hepatic encephalopathy.

RESULTS

EAD incidence was 23%. Median intensive care unit (ICU) and hospital stays were longer for recipients with EAD than those without (4 days vs. 3 days, P = 0.0001; 24 vs. 15 days, P = 0.0001, respectively). Three-year recipient and graft survival were worse in those with EAD than in those without (68% vs. 83%, P = .0001; 61% vs. 79%, P = 0.0001). A logistic regression model combining donor, graft, and recipient factors predicted EAD better than models examining these factors in isolation. Pretransplant recipient elevations in PT and bilirubin, awaiting a graft in hospital or ICU, donor age > or =50 years, donor hospital stay >3 days, preprocurement acidosis, and cold ischemia time > or =15 hr were independently associated with EAD.

CONCLUSION

Recipients who develop EAD have longer ICU and hospital stays and greater mortality than those without. Donor, graft, and recipient risk factors all contribute to the development of EAD. Results of these analyses identify factors that, if modified, may alter the risk of EAD.

Weight change and obesity after liver transplantation: incidence and risk factors

Obesity is a concern in the long-term management of patients following liver transplantation, yet the risk of obesity and the factors that influence its development have not been well defined. We evaluated posttransplantation weight change among a cohort of 774 adults who had their height and weight recorded before liver transplantation at three major centers. Obesity was defined as a body mass index (BMI) of at least 30 kg/m2. Weight at transplantation was adjusted by the amount of ascites removed. Mean BMI increased from 24.8 kg/m2 pretransplantation to 27.0 kg/m2 in the first posttransplantation year, to 28.1 kg/m2 in the second year, and very little with subsequent observation. Among 320 patients who were not obese before transplantation, 21.6% became obese within 2 years after transplantation. On evaluation of numerous potential donor and pretransplantation risk factors, greater recipient BMI, greater donor BMI, and being married were found to be predictors of subsequent obesity (P < .05). Posttransplantation predictors of obesity included absence of acute cellular rejection, higher cumulative prednisone dose in the second year, and cyclosporine-based immunosuppression, although only rejection and prednisone dose remained predictors on multivariate analysis. Despite the marked weight gain after transplantation, prevalence of obesity at 2 years was only slightly greater than in the general US population. Obesity occurred commonly after liver transplantation, sometimes with a striking gain in weight. In addition to BMI at transplantation, donor BMI, marital status, occurrence of acute rejection, and prednisone dose affected the incidence of obesity.

Review article: the management of acute liver failure

Acute liver failure (ALF) is a relatively uncommon but dramatic clinical syndrome with high mortality rates, in which a previously normal liver fails within days or weeks. Paracetamol overdose remains the major cause of ALF in the UK, while viral hepatitis is the commonest cause world-wide. Cerebral oedema is the leading cause of death in patients with ALF. Despite advances in intensive care and the development of new treatment modalities, ALF remains a condition of high mortality best managed in specialist centres. Orthotopic liver transplantation is the only new treatment modality that has made a significant impact in improving outcome. Bioartificial liver support systems and hepatocyte transplantation are new promising treatment options that may change the management of ALF in the future.

Chronic liver allograft rejection: a National Institute of Diabetes and Digestive and Kidney Diseases interinstitutional study analyzing the reliability of current criteria and proposal of an expanded definition. National Institute of Diabetes and Digestive and Kidney Diseases Liver Transplantation Database

A study was conducted to assess the inter and intrarater agreement for the histopathologic features and diagnosis of chronic rejection (CR) and several other important causes of late liver allograft dysfunction. On two occasions, five pathologists, experienced with liver transplantation, reviewed a set of 49 slides representing a range of diagnoses, without knowledge of the clinical history or liver injury test results. The readings were correlated with the original histopathologic diagnosis, liver injury tests, and clinicopathologic follow-up. Assessment of biopsy adequacy (kappa = 0.69) and portal tract counts (kappa = 0.79) showed good to excellent intrarater agreement, whereas interrater agreement for these variables was moderate to good, respectively (kappa = 0.44 and 0.65). Likewise, the intrarater agreement for the diagnosis of CR (kappa = 0.68), hepatitis (kappa = 0.77), and obstructive cholangiopathy (kappa = 0.55) showed good to excellent agreement, whereas the interrater agreement for these same diagnoses ranged from fair to good (kappa = 0.58, 0.46, and 0.25, respectively). In 18 specimens, there was a near unanimous diagnosis of CR across both readings. These biopsies were obtained at a median of 7.1 months (range, 42 days to 4.9 years) after transplantation, and the average number of portal tracts was 8.4 (range, 4-15). Interestingly, only 13 of these 18 specimens showed bile duct loss in >50% of the portal triads; the remaining cases showed atrophy/pyknosis of the biliary epithelium in a majority of small bile ducts. Clinicopathologic correlation showed that these 18 biopsies were obtained from 16 grafts from 15 patients, 14 of whom ultimately required retransplantation or died of or with CR, whereas two of the grafts/patients recovered. A high rate of sensitivity (92%) and a somewhat lower, but acceptable, rate of specificity (71% to 80%) was found for the diagnosis of CR. Chronic rejection and other causes of late liver allograft dysfunction can be diagnosed reliably by a group of pathologists experienced with liver transplantation, and the diagnosis of CR correlates with clinical course and liver function abnormalities. Expanded criteria for the diagnosis of CR are presented, and potential problem areas for practicing pathologists are discussed.

Increased waiting time for liver transplantation results in higher mortality

BACKGROUND

Waiting time to liver transplantation (LTx) has dramatically lengthened, but the proportion of candidates who die awaiting transplantation has not increased. We evaluated whether longer waiting time for LTx candidates increases mortality.

METHODS

A cohort of candidates listed for LTx between 1990 and 1993 by three large transplantation programs was followed for 2 years. The exposure measure was ABO blood type, which is not inherently related to outcome, but is a major determinant of waiting time. The main outcome measure was 2-year mortality, as evaluated by logistic regression analysis that controlled for differences in clinical status at the time of evaluation for LTx.

RESULTS

The 308 candidates with type O blood waited longer for LTx (median 109 days) than the 399 candidates with other blood types (median 58 days) (P=0.001). Candidates listed for LTx with type O blood had better clinical status at evaluation, but then had higher pretransplantation mortality (13.3%) than other candidates (7.0%) (P=0.005). Blood group O candidates had higher 2-year mortality (26.6%) than other candidates (22.1%), which on multivariate analysis resulted in a mortality odds ratio at 2 years of 1.52 (95% confidence interval=1.04-2.23). With the difference in median waiting time between blood groups increasing from 44 days in the first year to 108 days in the third year, the 2-year mortality odds ratio also rose from 0.94 to 1.97.

CONCLUSIONS

When compared with LTx candidates with other blood types, blood type O candidates have longer waiting times and higher pretransplantation mortality, which results in higher 2-year mortality.