Scott L. Nyberg

Prospective, randomized, multicenter, controlled trial of a bioartificial liver in treating acute liver failure

Objective:The HepatAssist liver support system is an extracorporeal porcine hepatocyte-based bioartificial liver (BAL). The safety and efficacy of the BAL were evaluated in a prospective, randomized, controlled, multicenter trial in patients with severe acute liver failure. Summary Background Data:In experimental animals with acute liver failure, we demonstrated beneficial effects of the BAL. Similarly, Phase I trials of the BAL in acute liver failure patients yielded promising results. Methods:A total of 171 patients (86 control and 85 BAL) were enrolled. Patients with fulminant/subfulminant hepatic failure and primary nonfunction following liver transplantation were included. Data were analyzed with and without accounting for the following confounding factors: liver transplantation, time to transplant, disease etiology, disease severity, and treatment site. Results:For the entire patient population, survival at 30 days was 71% for BAL versus 62% for control (P = 0.26). After exclusion of primary nonfunction patients, survival was 73% for BAL versus 59% for control (n = 147; P = 0.12). When survival was analyzed accounting for confounding factors, in the entire patient population, there was no difference between the 2 groups (risk ratio = 0.67; P = 0.13). However, survival in fulminant/subfulminant hepatic failure patients was significantly higher in the BAL compared with the control group (risk ratio = 0.56; P = 0.048). Conclusions:This is the first prospective, randomized, controlled trial of an extracorporeal liver support system, demonstrating safety and improved survival in patients with fulminant/subfulminant hepatic failure.

Acute liver failure: Summary of a workshop

Acute liver failure (ALF) is a rare but challenging clinical syndrome with multiple causes; a specific etiology cannot be identified in 15% of adult and 50% of pediatric cases. The course of ALF is variable and the mortality rate is high. Liver transplantation is the only therapy of proven benefit, but the rapidity of progression and the variable course of ALF limit its use. Currently in the United States, spontaneous survival occurs in approximately 45%, liver transplantation in 25%, and death without transplantation in 30% of adults with ALF. Higher rates of spontaneous recovery (56%) and transplantation (31%) with lower rates of death (13%) occur in children. The outcome of ALF varies by etiology, favorable prognoses being found with acetaminophen overdose, hepatitis A, and ischemia (≈60% spontaneous survival), and poor prognoses with drug‐induced ALF, hepatitis B, and indeterminate cases (≈25% spontaneous survival). Excellent intensive care is critical in management of patients with ALF. Nonspecific therapies are of unproven benefit. Future possible therapeutic approaches include N‐acetylcysteine, hypothermia, liver assist devices, and hepatocyte transplantation. Advances in stem cell research may allow provision of cells for bioartificial liver support. ALF presents many challenging opportunities in both clinical and basic research. (HEPATOLOGY 2008.)

Complete avoidance of calcineurin inhibitors in renal transplantation : A randomized trial comparing sirolimus and tacrolimus

Calcineurin inhibitors have decreased acute rejection and improved early renal allograft survival, but their use has been implicated in the development of chronic nephrotoxicity. We performed a prospective, randomized trial in kidney transplantation comparing sirolimus‐MMF‐prednisone to tacrolimus‐MMF‐prednisone. Eighty‐one patients in the sirolimus group and 84 patients in the tacrolimus group were enrolled (mean follow‐up = 33 months; range 13–47 months). At 1 year, patient survival was similar in the groups (98% with sirolimus, 96% with tacrolimus; p = 0.42) as was graft survival (94% sirolimus vs. 92% tacrolimus, p = 0.95). The incidence of clinical acute rejection was 10% in the tacrolimus group and 13% in the sirolimus group (p = 0.58). There was no difference in mean GFR measured by iothalamate clearance between the tacrolimus and sirolimus groups at 1 year (61 ± 19 mL/min vs. 63 ± 18 mL/min, p = 0.57) or 2 years (61 ± 17 mL/min vs. 61 ± 19 mL/min, p = 0.84). At 1 year, chronicity using the Banff schema showed no difference in interstitial, tubular or glomerular changes, but fewer chronic vascular changes in the sirolimus group. This study shows that a CNI‐free regimen using sirolimus‐MMF‐prednisone produces similar acute rejection rates, graft survival and renal function 1–2 years after transplantation compared to tacrolimus‐MMF‐prednisone.

Wound-healing complications after kidney transplantation: a prospective, randomized comparison of sirolimus and tacrolimus.

Background. Sirolimus has been associated with an increased risk of wound-healing complications in several retrospective analyses. The authors compared the rates of wound-healing complications in renal allograft recipients in a prospective, randomized trial of sirolimus-mycophenolate mofetil-prednisone versus tacrolimus-mycophenolate mofetil-prednisone. Methods. All patients received antithymocyte globulin induction. In the first phase of the study, patients (n=77) were included regardless of body mass index (BMI). In the second phase (n=46 patients), the authors excluded patients with a BMI greater than 32 kg/m2, and the target trough sirolimus level was lowered to 10 to 15 ng/mL (previously 15–20 ng/mL). Multivariate logistic regression analyses were performed to identify predictors of wound complications. Results. Fifty-nine patients received tacrolimus and 64 received sirolimus and were included in subsequent analyses. The incidence of complications was 8% (5 of 59) in the tacrolimus group and 47% (30 of 64) in the sirolimus group (P <0.0001). Rates of perigraft fluid collections, superficial wound infections, and incisional herniae were significantly higher in the sirolimus group. Multivariate logistic regression showed only sirolimus (P =0.0001) and BMI (P =0.0021) to independently correlate with complications. In the first phase of the study, the wound complication rate in the sirolimus group was 55% (21 of 38 patients). After excluding obese recipients and decreasing the target sirolimus level, the wound complication rate in the sirolimus group was 35% (9 of 26 patients; P =0.1040). Conclusions. The use of sirolimus-based immunosuppressive regimens leads to a higher incidence of wound-healing complications and will require new approaches to patient selection and management to decrease their incidence.

Overcoming a Positive Crossmatch in Living‐Donor Kidney Transplantation

Many patients who have an otherwise acceptable living‐kidney donor do not undergo transplantation because of the presence of antibodies against the donor cells resulting in a positive crossmatch. In the current study, 14 patients with a positive cytotoxic crossmatch (titer ≤ 1 : 16) against their living donor underwent a regimen including pretransplant plasmapheresis, intravenous immunoglobulin, rituximab and splenectomy. Eleven of 14 grafts (79%) are functioning well 30–600 days after transplantation. Two grafts were lost to accelerated vasculopathy and one was lost to death with good function. No hyperacute or cellular rejections occurred. Antibody‐mediated rejection occurred in six patients [two clinical (14%) and four subclinical (29%)] and was reversible with plasmapheresis and steroids. Our results suggest that selected crossmatch‐positive patients can be transplanted successfully with living‐donor kidney allografts, using a protocol of pretransplant plasmapheresis, intravenous immunoglobulin, rituximab and splenectomy. Longer follow‐up will be needed, but the absence of anti‐donor antibody and good early outcomes are encouraging.

Survival in portopulmonary hypertension: Mayo Clinic experience categorized by treatment subgroups.

To determine the natural history of portopulmonary hypertension (POPH), a retrospective screening‐right heart catheterization‐survival analysis of patients was performed. We categorized patients by three treatment subgroups: (1) no therapy for pulmonary hypertension (PH) or liver transplantation (LT), (2) therapy for PH alone and (3) therapy for PH followed by LT. Seventy‐four patients were identified between 1994 and 2007. Nineteen patients received no therapy for PH and no LT representing the natural history of POPH. Five‐year survival was 14%, and 54% had died within 1 year of diagnosis. Five‐year survival in 43 patients receiving therapy for PH but no LT was 45%, and 12% had died within 1 year of diagnosis. Twelve patients underwent LT and 5‐year survival for the nine receiving therapy for PH was 67% versus 25% in the three who were not pretreated with prostacyclin therapy. The survival of untreated patients with POPH was poor. Subgroups of patients selected to medical treatment with or without LT had better long‐term survival. Mortality did not correlate with baseline hemodynamic variables, type of liver disease or severity of hepatic dysfunction. Medical therapy for POPH should be considered in all patients with POPH, but the treatment effects and impact on those considered for LT still requires well‐designed, prospective study before practice guidelines can be suggested.

ABO-incompatible kidney transplantation using both A2 and non-A2 living donors

Background. Given the scarcity of cadaveric organs, efforts are intensifying to increase the availability of living donors. The current study assessed the feasibility of using ABO-incompatible living-donor kidneys to expand the donor pool. Methods. The authors performed 18 ABO-incompatible living-donor kidney transplants between May 1999 and April 2001. Ten patients received living-donor kidneys from A2 and eight patients received kidneys from non-A2 blood group donors. Immunosuppression consisted of Thymoglobulin antibody induction, tacrolimus, mycophenolate mofetil, and prednisone. Eight non-A2 and two A2 kidney recipients also received a pretransplant conditioning regimen of four plasmapheresis treatments followed by intravenous immunoglobulin and splenectomy at the time of transplantation. Antidonor blood group antibody titer was measured at baseline, pretransplant, at 1- to 3-month and 1-year follow-up, and at the time of diagnosis of antibody-mediated rejection. Results. No hyperacute rejection episodes occurred. One-year graft and patient survival rates in the 18 ABO-incompatible recipients were only slightly lower than those of 81 patients who received ABO-compatible kidney transplants during the same period (89% vs. 96% and 94% vs. 99%, respectively). Glomerular filtration rate and serum creatinine levels did not differ between the groups. Antibody-mediated rejection occurred in 28% of ABO-incompatible recipients, and was reversible with plasmapheresis, intravenous immunoglobulin, and increasing immunosuppression in all patients except one. Conclusions. ABO-incompatible living donor kidney transplants can achieve an acceptable 1-year graft survival rate using an immunosuppressive regimen consisting of Thymoglobulin induction, tacrolimus, mycophenolate mofetil, and prednisone combined with pretransplant plasmapheresis, intravenous immunoglobulin, and splenectomy.

Improved Scoring System to Assess Adult Donors For Cadaver Renal Transplantation

We previously proposed a quantitative approach to assess donor organs for cadaver renal transplantation. To improve on our original scoring system, we studied 34 324 patients who received cadaver renal transplants from adult donors between 1994 and 1999 and were reported to the UNOS Scientific Renal Transplant Registry. A scoring system was developed from five donor variables (age, 0–25 points; history of hypertension, 0–4; creatinine clearance before procurement, 0–4; cause of death, 0–3; HLA mismatch, 0–3) that showed a significant correlation with renal function and long‐term graft survival. Cadaver kidneys were stratified by cumulative donor score: grade A, 0–9 points; grade B, 10–19; grade C, 20–29; and grade D, 30–39. The influence of donor score on renal function and graft survival was most severe above 20 points, designated ‘marginal’ kidneys. In summary, a donor scoring system developed from a large population database was useful in predicting outcome after cadaver renal transplantation. The improved system provides a quantitative approach to evaluation of marginal kidneys and may improve allocation of these organs in cadaver renal transplantation.

Predictors of Disease Recurrence Following Neoadjuvant Chemoradiotherapy and Liver Transplantation for Unresectable Perihilar Cholangiocarcinoma

Background. Sixty-five patients with unresectable hilar cholangiocarcinoma (CCA) have undergone orthotopic liver transplantation (OLT) after neoadjuvant chemoradiotherapy per a clinical care protocol developed in 1993. We reviewed our experience with the aim to identify clinicopathological predictors of disease recurrence. Methods. All patients with CCA that underwent OLT at our institution between 1993 and January 1, 2006 were treated in accord with our published protocol. We analyzed multiple clinical and explant pathologic factors using Cox regression analysis. Results. Sixty-five patients with CCA underwent OLT. Four patients died within six months due to postoperative complications. At last follow-up, 11 patients (17%) had developed recurrence seven to 64 months after OLT. Mean time to recurrence was 29 months, and eight patients had died from recurrent disease. Patient and disease-free survival were 76% and 60% five years after OLT. Predictors of recurrence were older age, pretransplant cancer antigen (CA) 19-9 >100 U/ml, prior cholecystectomy, mass on cross-sectional imaging, residual tumor in explant >2 cm, tumor grade and perineural invasion in explant. Underlying primary sclerosing cholangitis, percutaneous biliary intubation, gender, and other time points for CA 19-9 were not associated with recurrence. Prolonged staging-to-OLT intervals for patients transplanted after implementation of model for end-stage liver disease (MELD) showed a trend toward increased recurrence. Conclusions. Older patients and those with high CA-19.9 levels, and larger tumors are more likely to develop recurrent disease. Prolonged waiting time may emerge as a significant risk factor with longer follow-up. These findings may guide patient selection, applicability of live donor transplantation and MELD score exceptions for this aggressive protocol.

MELD and Other Factors Associated with Survival after Liver Transplantation

Allocation of cadaveric livers for transplantation in the United States is now based on the severity of illness as determined by the model for end‐stage liver disease (MELD) score, a function of bilirubin, creatinine and international normalized ratio (INR). The aim of our study was to determine the association of various pre‐transplant risk factors, including the MELD score, on patient survival after orthotopic liver transplantation (OLT). The medical records of 499 consecutive patients (233 female, 266 males, mean age 50.9 ± 10.6 years) undergoing cadaveric OLT at our institution between June 1990 and February 1998 were reviewed. In the 407 patients alive at the latest contact, follow‐up was 4.7 years, with a minimum of 20 months (maximum of 9.4 years). Variables considered for analysis included MELD score, age, pre‐transplant renal dysfunction requiring dialysis, Child–Pugh classification, underlying liver disease, diabetes mellitus, and heart disease (ischemic/valvular/other). There were 92 deaths during follow‐up. In univariate analysis, the MELD score, renal failure requiring hemodialysis pre‐OLT, age > 42 years, and underlying etiology of liver disease were significantly associated with death during long‐term follow‐up. In multivariate models, age, underlying etiology of liver disease and renal failure requiring hemodialysis were independent predictors of death after OLT.