Biomedical subjects
Publications and source records attributed to J R Lake.
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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.
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.
BACKGROUND: Neoral is a microemulsion formulation of cyclosporine that has a better pharmacokinetic profile than the standard formulation (Sandimmune). To prove the safety of converting stable liver transplant patients from Sandimmune to Neoral, we conducted a prospective trial involving 54 patients. METHOD: The average time from transplantation to conversion was 48.5+/-21.6 months. Thirty of 54 patients (55%) required a dose reduction during the study for various reasons. Five of 30 patients had the first dose reduction because of increased levels of cyclosporine. Seven patients required more than one dose reduction. RESULTS: Sixteen patients suffered serious adverse events. Six patients had a biopsy-proven rejection. Four of 6 patients had trough cyclosporine levels within 20% of baseline value immediately before developing rejection. CONCLUSION: Converting patients from the standard formulation to the microemulsion formulation of cyclosporine seems to expose stable patients to unnecessary risks.
Mutations in the "a" determinant of the surface gene have been associated with failure of hepatitis B immunoglobulin (HBIg) prophylaxis. We compared sequences from the surface and polymerase regions of hepatitis B virus (HBV) from 4 patients who failed high-dose HBIg therapy with two control groups: HBIg-treated patients who remained hepatitis B surface antigen (HBsAg)-negative (n = 4) and HBV-infected transplant recipients who never received HBIg (n = 4). Mutations within the surface and overlapping polymerase region were more common in patients failing HBIg than controls (P = .03), and mutations in the region of the "a" determinant were present only in patients failing HBIg. To examine the relationship between HBIg failure and duration of therapy, five additional treatment failures from a second transplantation center were sequenced (total with HBIg failure = 9). Mutations in the "a" determinant developed in 1 of 3 patients receiving HBIg for less than 6 months compared with 5 of 6 patients failing HBIg after 6 months of therapy (P = .23). The most frequently identified amino acid substitution was glycine to arginine at position 145 (present in 4 of 6 patients who failed HBIg after at least 6 months of treatment). A unique mutation within the YMDD motif (methionine to leucine) was present in 1 patient who failed HBIg treatment and who received a short course of ganciclovir. We conclude that the emergence of mutations in the "a" determinant accounts for some, but not all, treatment failures in patients receiving HBIg prophylaxis. Mutations in other regions of the S gene were more common in patients failing HBIg than controls, suggesting that domains other than the "a" determinant may be important.
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.
A multicenter, retrospective analysis of 623 liver transplant recipients was performed to define safe and effective cyclosporine doses and blood levels at various times after transplantation. Patient and graft survival were assessed as efficacy parameters, and serum creatinine and cholesterol levels as safety parameters. The mean daily cyclosporine dose was 12.1 mg/kg/d at 1 month posttransplantation and 5.5 mg/kg/d after 1 year. After 4 years, the mean cyclosporine dose was maintained at 4.0 mg/kg/d. Mean cyclosporine blood levels showed a similar trend. Patient and graft survival after 4 years of cyclosporine maintenance therapy were 72% and 67%, respectively. Both serum creatinine and cholesterol levels were stable over the study period, and neither correlated with cyclosporine dose. The cumulative incidence of biopsy-proven acute cellular rejection was 59% for early (< 6 months) episodes and 21% for late (> or = 6 months) episodes. Patient and graft survival did not differ significantly between patients experiencing early or late acute rejection episodes and those who did using univariate analysis. The high patient and graft survival, low rejection rates, and lack of significant renal dysfunction or hypercholesterolemia suggest that the cyclosporine doses and blood levels described are safe and therapeutically effective.
BACKGROUND: Orthotopic liver transplantation (OLT) is a highly effective but costly therapy for end-stage liver disease. However, there are limited data on the demographic and clinical variables that affect cost. We undertook a preliminary study using multiple regression techniques to analyze factors that influence the cost of OLT. METHODS: Patient and demographic data, including laboratory values and charges for all liver transplantations performed between June 1992 and June 1993 were analyzed (n = 111). Linear regression with standard and log-transformed values was performed by using STATA software (Stata Corporation College Station, TX). Independent variables included in the analyses were age, sex, United Network for Organ Sharing (UNOS) status, primary versus retransplantation, liver-kidney transplantation, and laboratory parameters of both liver (aspartate aminotransferase, AST; alkaline phosphatase; bilirubin; albumin; and prothrombin time) and kidney (blood urea nitrogen, BUN; creatinine) function. An F-to-remove strategy was employed with a significance level set at P = .05. RESULTS: The full model with 12 variables explained 37% of the total variation in charges. When one excludes variables that did not have a significant impact on cost, the remaining significant variables were BUN and UNOS status 1. The final model was Charges (US$) = 3,407 x BUN + 74,474 x status 1 + 102,662. This model accounted for 29% of the total variability with BUN accounting for the vast majority (26%). CONCLUSIONS: Renal function is the most important predictor of cost of OLT (P < .001). UNOS status 1 further increases cost, but other hospitalized patients have similar costs when one controls for other clinical variables. The degree of liver impairment is less important in predicting cost.
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.
This study was designed to determine the cause of posttransplantation hepatitis in patients undergoing transplantation for liver disease of nonviral cause; the role of acquired hepatitis B virus (HBV), hepatitis C virus (HCV), and hepatitis G virus (HGV) in posttransplantation hepatitis; and the course of posttransplantation hepatitis of unknown cause. Two hundred forty-three patients underwent transplantation for nonviral liver diseases (mean age, 48 years; 103 men, 140 women). Serological and virological assays for HBV and HCV were performed pretransplantation to exclude preexisting infection and posttransplantation to investigate the cause of posttransplantation hepatitis. Histology was graded on all available biopsy specimens; posttransplantation hepatitis was assessable in 150 patients. Posttransplantation hepatitis was present in 29% (44 of 150) of the patients after a median follow-up of 47 months (range, 1 to 101 months). Actuarial survival was significantly lower in patients with posttransplantation hepatitis compared with patients without (71% v 89% at 5-year follow-up; P = .03). HCV and HBV were identified posttransplantation in 14% and 9% of patients with hepatitis, respectively. After the exclusion of HCV and HBV infection, 22% (33 of 150) of the patients had posttransplantation hepatitis of unknown cause. HGV was present in 58% of these patients, but HGV was equally prevalent in patients without posttransplantation hepatitis. When patients with HBV and HCV were excluded, there was no difference in survival between patients with posttransplantation hepatitis compared with patients without (P = .08, log-rank test). Posttransplantation hepatitis was present in approximately 30% of the patients undergoing transplantation for nonviral diseases, with a median follow-up of 47 months. Known hepatitis viruses (HBV, HCV) were present in one fourth of the patients with posttransplantation hepatitis; 22% (33 of 150) of the patients had hepatitis of unknown cause, suggesting that other, as yet undiscovered, hepatitis viruses may exist.
Nitric oxide synthesis contributes to opiate tolerance and dependence. Nicotine dependence and abstinence syndrome in the rat appear to involve opiate mechanisms. Therefore, it was postulated that nitric oxide synthase (NOS) activity might be essential for the expression of nicotine abstinence syndrome. Twenty-one rats were rendered dependent by SC infusion of 9 mg/kg per day nicotine tartrate via Alzet osmotic minipump. Rats were pretreated SC with vehicle alone, or with 18 or 30 mg/kg of the NOS inhibitor L-NNA (nitro-L-arginine). Thirty minutes later, rats were challenged by 1 mg/kg of the nicotinic antagonist mecamylamine SC and observed for 30 additional minutes. Rats pretreated with vehicle displayed a total of 68.7+/-8.0 mecamylamine-precipitated abstinence signs (mean+/-SEM), while those receiving 18 or 30 mg/kg L-NNA had 12.7+/-2.0 and 5.1+/-1.7 signs, respectively. All three groups differed significantly from one another according to Dunn's post-hoc procedure. Rats pretreated with L-NNA combined with an excess of the NOS substrate L-arginine had significantly more mecamylamine-precipitated abstinence signs than rats receiving L-NNA combined with D-arginine. Also, D-NNA, which does not selectively bind to NOS, was significantly less effective than L-NNA in preventing mecamylamine-precipitated abstinence syndrome. Additional studies determined the effect of L-NNA on spontaneous nicotine abstinence syndrome. Rats were assessed for abstinence signs at 17 and 20 h after termination of nicotine infusion. They received injections of 9, 18, or 30 mg/kg L-NNA SC or vehicle alone immediately before the 20-h observation; all rats were observed for 30 min. Signs at 20 h (post-injection) as a percentage of signs at 17 h (pre-injection) declined significantly as a function of L-NNA dose. Once again, this effect was attenuated significantly more by co-administration of L-arginine than by D-arginine. The overall pattern of results suggests that nitric oxide synthesis is critical to the expression of nicotine abstinence syndrome.
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Rats infused subcutaneously with 9 mg/kg/day nicotine tartrate for 7 days exhibit behavioral abstinence signs following either termination of nicotine infusion or injection of the noncompetitive nicotinic antagonists mecamylamine (s.c.) or hexamethonium (ic.c.v.). This study examined the abstinence precipitating effects of dihydro-beta-erythroidine (DHbetaE), a competitive nicotinic antagonist. Twenty-four nicotine-dependent rats were injected in the third ventricle with 10, 18, or 25 microg DHbetaE in 20 microl saline or with saline alone and observed for abstinence signs over a 20-min period. There was a significant positive linear trend of overall abstinence signs as a function of dose, p < 0.01. In 12 nondependent rats, the high dose of DHbetaE did not induce more abstinence-like signs than saline alone. In a second experiment, 18 nicotine-dependent rats were injected s.c. with 1 or 6 mg/kg of the muscarinic antagonist scopolamine or with saline alone. Few abstinence signs were observed in any group: there was no significant drug effect. The results suggest that nicotine abstinence signs observed in the rat are specific to reduced stimulation of previously overstimulated nicotinic receptors.
The objective of this study was to analyze a series of patients with Enterococcus faecium infection following transjugular intrahepatic portosystemic shunts (TIPS) in order to define the risk factors, outcome, and role of treatment including hepatic transplantation. This study is a case series from a tertiary referral center for liver transplantation. The medical records of four patients referred to one teaching hospital in San Francisco between 1990 and 1995 for evaluation or management of Enterococcal infection following TIPS were reviewed. A review of the microbiology records of all 314 patients who underwent TIPS at that institution and a MEDLINE search were performed to assess whether any other cases existed. The effect of therapy on survival was assessed, in particular, the repeated use of TIPS and prolonged courses of antibiotics. All four patients had thrombosis of their TIPS at the time of diagnosis of enterococcal bacteremia. All were treated with prolonged courses of intravenous antibiotics. One patient had echocardiographic evidence of subacute bacterial endocarditis with chronic aortic insufficiency. In all cases, liver transplantation was contraindicated in the acute setting because of uncontrolled endovascular infection. Two of four patients survived; these were the only two patients who had had a successful repeat TIPS. Enterococcal bacteremia is a rare complication following TIPS but carries a high mortality. It usually occurs in the setting of technically difficult TIPS with shunt thrombosis. Management should be focused on long term antibiotics and attempts at reestablishment of portal decompression with another TIPS. Liver transplantation should not be considered until the infection is cleared. Prophylaxis for Enterococcus species should be considered in technically difficult or unsuccessful TIPS.
Most liver diseases for which liver transplantation is performed recur after liver transplantation. The clinical impact of recurrence varies. For autoimmune liver diseases, such as primary biliary cirrhosis, primary sclerosing cholangitis, and autoimmune hepatitis, clinically significant recurrence appears to be relatively rare. Whether these diseases recur in any meaningful way after liver transplantation is still controversial. For the chronic viral diseases, hepatitis B and C, the issue is not whether they recur--they clearly do--but whether the recurrence affects prognosis and how best to manage recurrent disease. For hepatitis B virus (HBV), reinfection can lead to accelerated liver injury, graft loss, and dramatically worse patient and graft survival rates, whereas the prognosis of recurrent hepatitis C virus (HCV), at least in the short-term, appears to be more benign. Major advances have been made in preventing liver allograft reinfection with HBV. Before these advances, chronic hepatitis B was considered a relative contraindication to liver transplantation because the allografts almost always became reinfected. With the current strategies for preventing HBV reinfection, however, the graft and patient survival rates after transplantation for chronic hepatitis B approach those for nonviral diseases. The development of resistance to antiviral therapy is likely to represent the major problem in the future and mandate the use of combination therapy. There is currently no effective therapy available for recurrent hepatitis C. Until such therapy is developed, recurrent hepatitis C remains the most challenging problem facing liver transplant physicians and surgeons.
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.
BACKGROUND: A study was performed by 17 different U.S. liver transplantation centers to determine the safety and efficacy of conversion from cyclosporine to tacrolimus for chronic allograft rejection. METHODS: Ninety-one patients were converted to tacrolimus a mean of 319 days after liver transplantation. The indication for conversion was ongoing chronic rejection confirmed by biochemical and histologic criteria. Patients were followed for a mean of 251 days until the end of the study. RESULTS: Sixty-four patients (70.3%) were alive with their initial hepatic allograft at the conclusion of the study period and were defined as the responder group. Twenty-seven patients (29.7%) failed to respond to treatment, and 20 of them required a second liver graft. The actuarial graft survival for the total patient group was 69.9% and 48.5% at 1 and 2 years, respectively. The actuarial patient survival at 1 and 2 years was 84.4% and 81.2%, respectively. Two significant positive prognostic factors were identified. Patients with a total bilirubin of < or = 10 mg/dl at the time of conversion had a significantly better graft and patient survival than patients converted with a total bilirubin > 10 mg/dl (P=0.00002 and P=0.00125, respectively). The time between liver transplantation and conversion also affected graft and patient survival. Patients converted to tacrolimus < or = 90 days after transplantation had a 1-year actuarial graft and patient survival of 51.9% and 65.9%, respectively, compared with 73.2% and 87.7% for those converted > 90 days after transplantation. The mean total bilirubin level for the responder group was 7.1 mg/dl at the time of conversion and decreased significantly to a mean of 3.4 mg/dl at the end of the study (P=0.0018). Thirteen patients (14.3%) died during the study. Sepsis was the major contributing cause of death in most of these patients. CONCLUSIONS: Our results suggest that conversion to tacrolimus for chronic rejection after orthotopic liver transplantation represents an effective therapeutic option. Conversion to tacrolimus before development of elevated total bilirubin levels showed a significant impact on long-term outcome.