Conformationally averaged iterative Brownian dynamics simulations of semidilute polymer solutions.

The dynamics of semidilute polymer solutions are important to many polymer solution processing techniques such as fiber spinning and solution printing. The out-of-equilibrium molecular conformations resulting from processing flows directly impact material properties. Brownian dynamics (BD) simulations are a standard technique for studying this connection between polymer conformations in solution and processing flows because they can capture molecular-level polymer dynamics. However, BD simulations of semidilute polymer solutions are computationally limited by the calculation of hydrodynamic interactions (HIs) via an Ewald summed diffusion tensor and stochastic Brownian displacements via the decomposition of the diffusion tensor. Techniques based on the Cholesky decomposition scale with the number of particles N as O(N 3) and approximations in the literature have reduced this scaling to as low as O(N). These methods still require continuous updating of the diffusion tensor and Brownian displacements, resulting in a significant constant per-time step cost. Previously, we introduced a method that avoids this cost for dilute polymer solutions by iterative conformational averaging (CA) of intramolecular HIs. In this work, we extend the CA method to semidilute solutions by introducing a grid-space average of intermolecular HIs and a pairwise approximation to the Brownian displacements based on the truncated expansion ansatz of Geyer and Winter. We evaluate our method by first comparing the computational cost with that of other simulation techniques. We verify our approximations by comparison with expected results for static and dynamic properties at equilibrium and use our method to demonstrate the concentration dependence of HI screening.

Comparison of two equivalent model for end-stage liver disease scores for hepatocellular carcinoma patients using data from the United Network for Organ Sharing liver transplant waiting list registry.

Patients with hepatocellular carcinoma (HCC) have been advantaged on the liver transplant waiting list within the United States, and a 6-month delay and exception point cap have recently been implemented to address this disparity. An alternative approach to prioritization is an HCC-specific scoring model such as the MELD Equivalent (MELDEQ ) and the mixed new deMELD. Using data on adult patients added to the UNOS waitlist between 30 September 2009 and 30 June 2014, we compared projected dropout and transplant probabilities for patients with HCC under these two models. Both scores matched actual non-HCC dropout in groups with scores <22 and improved equity with non-HCC transplant probabilities overall. However, neither score matched non-HCC dropout accurately for scores of 25-40 and projected dropout increased beyond non-HCC probabilities for scores <16. The main differences between the two scores were as follows: (i) the MELDEQ assigns 6.85 more points after 6 months on the waitlist and (ii) the deMELD gives greater weight to tumor size and laboratory MELD. Post-transplant survival was lower for patients with scores in the 22-30 range compared with those with scores <16 (P = 0.007, MELDEQ ; P = 0.015, deMELD). While both scores result in better equity of waitlist outcomes compared with scheduled progression, continued development and calibration is recommended.

The relationship between dynamic and pseudo-thermodynamic measures of the glass transition temperature in nanostructured materials.

Despite decades of research on the effects of nanoconfinement on the glass transition temperature Tg, apparent discrepancies between pseudothermodynamic and dynamic measurements of these effects have raised questions regarding the presence of long-ranged interfacial dynamic gradients in glass-forming liquids. Here we show that these differences can be accounted for based on disparities in these methods' weightings over local Tg's within an interfacial gradient. This finding suggests that a majority of experimental data are consistent with a broad interfacial dynamic interphase in glass-forming liquids.

Does fragility of glass formation determine the strength of Tg-nanoconfinement effects?

Nanoscale confinement has been shown to alter the glass transition and associated mechanical and transport properties of glass-forming materials. Inspired by expected interrelations between nanoconfinement effects, cooperative dynamics in supercooled liquids, and the "fragility" (or temperature-abruptness) of the glass transition, it is commonly expected that nanoconfinement effects on Tg should be more pronounced for more fragile glass formers. Here we employ molecular dynamics simulations of glass formation in the bulk and under nanoconfinement of model polymers in which we systematically tune fragility by several routes. Results indicate that a correlation between fragility and the strength of nanoconfinement effects is weak to modest at best when considering all systems but can appear to be stronger when considering a subset of systems. This outcome is consistent with a reanalysis of the Adam-Gibbs theory of glass formation indicating that fragility does not necessarily track in a universal way with the scale of cooperative motion in glass-forming liquids. Finally, we find that factors such as composition gradients or variability in measurement sensitivity to different parts of the dynamic gradient have the potential to significantly confound efforts to identify trends in Tg-nanoconfinement effects with variables such as fragility, emphasizing the importance of employing diverse data sets and multiple metrologies in the study of this problem.

Projected outcomes of 6-month delay in exception points versus an equivalent Model for End-Stage Liver Disease score for hepatocellular carcinoma liver transplant candidates.

The United Network for Organ Sharing (UNOS) recently implemented a 6-month delay before granting exception points to liver transplantation candidates with hepatocellular carcinoma (HCC) to address disparity in transplantation access between HCC and non-HCC patients. An HCC-specific scoring scheme, the Model for End-Stage Liver Disease equivalent (MELDEQ ), has also been developed. We compared projected dropout and transplant probabilities and posttransplant survival for HCC and non-HCC patients under the 6-month delay and the MELDEQ using UNOS data from October 1, 2009, to June 30, 2014, and multistate modeling. Overall (combined HCC and non-HCC) wait-list dropout was similar under both schemes and slightly improved (though not statistically significant) compared to actual data. Projected HCC wait-list dropout was similar between the MELDEQ and 6-month delay at 6 months but thereafter started to differ, with the 6-month delay eventually favoring HCC patients (3-year dropout 10.0% [9.0%-11.0%] for HCC versus 14.1% [13.6%-14.6%]) for non-HCC) and the MELDEQ favoring non-HCC patients (3-year dropout 16.0% [13.2%-18.8%] for HCC versus 12.3% [11.9%-12.7%] for non-HCC). Projected transplant probabilities for HCC patients were substantially lower under the MELDEQ compared to the 6-month delay (26.6% versus 83.8% by 3 years, respectively). Projected HCC posttransplant survival under the 6-month delay was similar to actual, but slightly worse under the MELDEQ (2-year survival 82.9% [81.7%-84.2%] versus actual of 85.5% [84.3%-86.7%]). In conclusion, although the 6-month delay improves equity in transplant and dropout between HCC and non-HCC candidates, disparity between the 2 groups may still exist after 6 months of wait-list time. Projections under the MELDEQ , however, appear to disadvantage HCC patients. Therefore, modification to the exception point progression or refinement of an HCC prioritization score may be warranted. Liver Transplantation 22 1343-1355 2016 AASLD.

Simeprevir and sofosbuvir with or without ribavirin to treat recurrent genotype 1 hepatitis C virus infection after orthotopic liver transplantation.

Although combination simeprevir (SIM) plus sofosbuvir (SOF) is an approved regimen for genotype 1 chronic hepatitis C virus (HCV), data regarding its safety and efficacy in liver transplant recipients remain limited. A multicenter retrospective study was performed to determine the efficacy and tolerability of a 12-week regimen of SIM/SOF with or without ribavirin (RBV) in 56 consecutive liver transplant recipients in 2014; 79% of patients had genotype 1a, 14% had cirrhosis, and 73% were treatment experienced. Sustained virological response at 12 weeks (SVR12) was 88% by intention to treat analysis (95% confidence interval, 84%-90%). Four patients relapsed, but no on-treatment virological failures occurred. The Q80K polymorphism did not impact SVR12, but there was a trend toward decreased sustained virological response with advanced fibrosis (P = 0.18). HCV RNA was detectable at treatment week 4 in 21% of patients, and those who had detectable levels were less likely to achieve SVR12 (58% versus 95%; P = 0.003). Five patients had baseline Child-Pugh class B cirrhosis, and 2 of them died (1 following early discontinuation of therapy). An additional discontinuation resulted from a severe photosensitivity reaction in a patient on concomitant cyclosporine. Seven patients receiving RBV developed progressive anemia requiring intervention. Immunosuppression dose modifications were minimal. SIM/SOF for 12 weeks was effective and well tolerated by compensated liver transplant recipients especially when administered without concomitant RBV or cyclosporine. SIM/SOF appears to have a niche as the only 12-week RBV-free treatment regimen currently recommended by guidelines for compensated transplant recipients. However, 12 weeks may not be the optimal duration of therapy for those with detectable virus at week 4 or possibly for those with cirrhosis. These data require confirmation by prospective randomized clinical trials. Liver Transplantation 22 635-643 2016 AASLD.

Immunobiology in VCA.

Transplantation of vascularized composite tissue is a relatively new field that is an amalgamation of experience in solid organ transplantation and reconstructive plastic and orthopedic surgery. What is novel about the immunobiology of VCA is the addition of tissues with unique immunologic characteristics such as skin and vascularized bone, and the nature of VCA grafts, with direct exposure to the environment, and external forces of trauma. VCAs are distinguished from solid organ transplants by the requirement of rigorous physical therapy for optimal outcomes and the fact that these procedures are not lifesaving in most cases. In this review, we will discuss the immunobiology of these systems and how the interplay can result in pathology unique to VCA as well as provide potential targets for therapy.

MELDEQ : An alternative Model for End-Stage Liver Disease score for patients with hepatocellular carcinoma.

Multiple studies have demonstrated an advantage for hepatocellular carcinoma (HCC) patients under the current liver allocation system, such that the United Network for Organ Sharing (UNOS) recently voted in support of a proposal to delay granting Model for End-Stage Liver Disease (MELD) exception points to all HCC patients for 6 months, independently of a candidate's native MELD score or alpha-fetoprotein (AFP) level. We obtained UNOS data on adult patients who were added to the wait list between January 22, 2005 and September 30, 2009, and we explored the relationship between HCC, MELD, AFP, and other factors that contribute to not only dropout on the wait list but posttransplant survival as well. The aim was to establish an equivalent Model for End-Stage Liver Disease (MELDEQ ) score for HCC patients that would reduce the disparity in access to transplantation between HCC and non-HCC patients. We determined risk groups for HCC patients with dropout hazards equivalent to those of non-HCC patients, and we evaluated projections for HCC wait-list dropout/transplantation probabilities on the basis of the MELDEQ prioritization scheme. Projections indicate that lower risk HCC patients (MELDEQ ≤ 18) would have dropout probabilities similar to those of non-HCC patients in the same MELD score range, whereas dropout probabilities for higher risk HCC patients would actually be improved. The posttransplant survival of all HCC risk groups is lower than that of their non-HCC counterparts, with 1-year survival of 0.77 (95% CI, 0.70-0.85) for MELDEQ scores ≥ 31. These results suggest that HCC patients with a combination of a low biochemical MELD score and a low AFP level (MELDEQ ≤ 15) would receive a marked advantage in comparison with patients with chemical MELD scores in a similar range and that a delay of 6 months for listing may be appropriate. In contrast, patients with MELDEQ scores > 15 would likely be adversely affected by a universal 6-month delay in listing.

Training techniques in laparoscopic donor nephrectomy: a systematic review.

The learning curve to achieve competency in laparoscopic donor nephrectomy (LDN) is poorly outlined. Online databases were searched for training in LDN. Abstracts and manuscripts were excluded if they did not address introduction of a laparoscopic technique for donor nephrectomy. Relevant manuscripts were reviewed for surgical technique, use of animal models, co-surgeons, surgeon specialty and training, institution type/volume, and assessment of training method. Forty-four met inclusion criteria, with 75% describing the evolution from open to LDN. Eighty-two percent were from academic centers, and 36% were from centers performing <25 donor nephrectomies each year. The learner was an attending surgeon 80% of the time, mostly urologists with prior laparoscopy or open nephrectomy experience. The learning curve, defined by decreased operating time, averaged 35 cases. Improved intra-operative, patient, and recipient outcomes were observed for centers performing ≥50 LDNs annually. The United Network of Organ Sharing requires 15 cases as surgeon or assistant to be certified as the primary LDN surgeon. This falls below the described learning curve for LDN. The assessment of training and competency for LDN is heterogeneous, and objective learner-based metrics could help surgeons and institutions reach a quality standard for performing this operation.

The impact of recipient obesity on outcomes after renal transplantation.

BACKGROUND: The benefit of renal transplantation in obese patients is controversial, with many centers setting upper limits on body mass index (BMI) in consideration for listing patients for transplant. This study was undertaken to determine the effect of recipient obesity on delayed graft function (DGF) and graft survival after renal transplantation. METHODS: Retrospective review of all renal transplant recipients in the United Network for Organ Sharing database from January 1, 2004, through December 31, 2009, was performed. Primary endpoints were DGF and non-death-censored graft survival. Comparisons were made on the basis of the following weight classes: nonobese (BMI < 30), class I obese (30 ≤ BMI < 35), class II obese (35 ≤ BMI < 40), and class III obese (BMI ≥ 40). RESULTS: Multivariable logistic regression indicated a significantly increased risk for DGF in obese patients. The odds ratios for DGF compared with nonobese patients were 1.34 [95% confidence interval (CI) 1.27-1.42; P < 0.001], 1.68 (95% CI 1.56-1.82; P < 0.001), and 2.68 (95% CI 2.34-3.07; P < 0.001) for the class I obese, class II obese, and class III obese groups, respectively. Class I obesity was not a significant risk for non-death-censored graft failure [hazard ratio (HR) 1.00, 95% CI 0.95-1.05; P = 0.901] compared with nonobese patients. Patients in the class II obese (HR 1.15, 95% CI 1.07-1.24; P < 0.001) and class III obese (HR 1.26, 95% CI 1.11-1.43; P < 0.001) groups were at a significantly increased risk for graft failure than their nonobese counterparts. CONCLUSIONS: Obese patients in all weight classes are at an increased risk for DGF after renal transplantation, although differences in non-death-censored graft survival are such that transplantation should not be denied on the basis of BMI criteria alone.

Binding and cleavage of unstructured RNA by nuclear RNase P.

Ribonuclease P (RNase P) is an essential endoribonuclease for which the best-characterized function is processing the 5' leader of pre-tRNAs. Compared to bacterial RNase P, which contains a single small protein subunit and a large catalytic RNA subunit, eukaryotic nuclear RNase P is more complex, containing nine proteins and an RNA subunit in Saccharomyces cerevisiae. Consistent with this, nuclear RNase P has been shown to possess unique RNA binding capabilities. To understand the unique molecular recognition of nuclear RNase P, the interaction of S. cerevisiae RNase P with single-stranded RNA was characterized. Unstructured, single-stranded RNA inhibits RNase P in a size-dependent manner, suggesting that multiple interactions are required for high affinity binding. Mixed-sequence RNAs from protein-coding regions also bind strongly to the RNase P holoenzyme. However, in contrast to poly(U) homopolymer RNA that is not cleaved, a variety of mixed-sequence RNAs have multiple preferential cleavage sites that do not correspond to identifiable consensus structures or sequences. In addition, pre-tRNA(Tyr), poly(U)(50) RNA, and mixed-sequence RNA cross-link with purified RNase P in the RNA subunit Rpr1 near the active site in "Conserved Region I," although the exact positions vary. Additional contacts between poly(U)(50) and the RNase P proteins Rpr2p and Pop4p were identified. We conclude that unstructured RNAs interact with multiple protein and RNA contacts near the RNase P RNA active site, but that cleavage depends on the nature of interaction with the active site.

Accumulation of noncoding RNA due to an RNase P defect in Saccharomyces cerevisiae.

Ribonuclease P (RNase P) is an essential endoribonuclease that catalyzes the cleavage of the 5' leader of pre-tRNAs. In addition, a growing number of non-tRNA substrates have been identified in various organisms. RNase P varies in composition, as bacterial RNase P contains a catalytic RNA core and one protein subunit, while eukaryotic nuclear RNase P retains the catalytic RNA but has at least nine protein subunits. The additional eukaryotic protein subunits most likely provide additional functionality to RNase P, with one possibility being additional RNA recognition capabilities. To investigate the possible range of additional RNase P substrates in vivo, a strand-specific, high-density microarray was used to analyze what RNA accumulates with a mutation in the catalytic RNA subunit of nuclear RNase P in Saccharomyces cerevisiae. A wide variety of noncoding RNAs were shown to accumulate, suggesting that nuclear RNase P participates in the turnover of normally unstable nuclear RNAs. In some cases, the accumulated noncoding RNAs were shown to be antisense to transcripts that commensurately decreased in abundance. Pre-mRNAs containing introns also accumulated broadly, consistent with either compromised splicing or failure to efficiently turn over pre-mRNAs that do not enter the splicing pathway. Taken together with the high complexity of the nuclear RNase P holoenzyme and its relatively nonspecific capacity to bind and cleave mixed sequence RNAs, these data suggest that nuclear RNase P facilitates turnover of nuclear RNAs in addition to its role in pre-tRNA biogenesis.

Inflammatory myofibroblastic tumor of the liver in children.

Inflammatory pseudotumors, now more aptly termed inflammatory myofibroblastic tumors (IMTs), are uncommon benign neoplasms, which have been reported in most organs and tissues in the body. Originally described and commonly found in the lung, they are also found in the liver of children and adults. We review the literature and analyze the features of the hepatic IMTs reported in children, along with a case report of a 15-month-old boy who had a persistent IMT in the liver and underwent surgical resection for the same following a trial of conservative management.

Hand-assisted laparoscopic nephrectomy for polycystic kidney disease.

BACKGROUND AND OBJECTIVES: Historically, nephrectomy for autosomal dominant polycystic kidney disease was performed by an open technique. We performed this study to compare outcomes in hand-assisted laparoscopic nephrectomy with open nephrectomy in this population. METHODS: Charts of patients with autosomal dominant polycystic kidney disease who underwent nephrectomy by a transplant surgeon from January 1, 2000, to December 31, 2011, were reviewed. The hand-assisted laparoscopic nephrectomy group was compared with the open group. Data collected included unilateral versus bilateral nephrectomy, operative time, complications, transfusion requirement, and length of stay. RESULTS: Of the 78 patients identified, 18 underwent open transabdominal nephrectomy, 56 underwent hand-assisted laparoscopic nephrectomy, and 2 underwent hand-assisted laparoscopic nephrectomy that was converted to an open procedure. Two patients were excluded because another major procedure was performed at the same time as the nephrectomy. Operative times were similar. Patients undergoing open bilateral nephrectomy were more likely to receive transfusion (odds ratio, 3.57 [95% confidence interval, 0.74-17.19]; P = .016), and the length of stay was longer in the open groups (5.9 days vs 4.0 days for unilateral [P = .013] and 7.8 days vs 4.6 days for bilateral [P = .001]). Overall complication rates were similar. The most frequent complications associated with hand-assisted laparoscopic nephrectomy were the development of an incisional hernia at the hand-port site and arteriovenous fistula thrombosis. CONCLUSION: Hand-assisted laparoscopic nephrectomy can be safely performed without increased operative times or complications. The hand-assisted laparoscopic nephrectomy group enjoyed a shorter length of stay, and fewer patients in this group received transfusion. For patients considering renal transplantation, avoidance of transfusion is important to prevent sensitization and limiting access to compatible organs.

Monitoring and long-term outcomes in vascularized composite allotransplantation.

PURPOSE OF REVIEW: The field of vascularized composite allotransplantation (VCA) is young, with less than 150 transplants worldwide. However, we now possess as much as 14 years of clinical follow-up. There are similarities and distinct differences between solid-organ transplantation (SOT) and VCA. This review will summarize how VCA recipients are monitored, outcomes observed, and what aspects are unique to VCA. RECENT FINDINGS: Of about 90 documented cases, 10% of VCA recipients are out more than 10 years and 14% are out 5 or more years. There have been both graft losses and patient mortality. In most cases, these losses have been acute, most within the first year, and all within 3 years. Unlike SOT, VCA grafts function well during severe rejection. Chronic rejection-like sequelae are less frequent than in SOT, but do appear. Immunosuppression ranges from standard protocols to novel trials aimed at immunosuppression minimization. Patient selection greatly affects the outcome. Graft loss after year 1 is associated with compliance issues. SUMMARY: Functional outcomes have exceeded expectations. VCA recipients enjoy a quality of life not achievable with conventional reconstruction. Outstanding long-term results of more than a decade have been achieved. Monitoring of VCA patients will require new strategies to incorporate external visualization and effects of environment on rejection. Graft loss has occurred early, suggesting we focus improvement on this time period. More follow-up is needed to determine the rates and targets of chronic rejection, and the characteristics of VCA unique to face vs. hand transplantation.

Employment outcomes following successful renal transplantation.

BACKGROUND: Data on employment outcomes after successful renal transplantation are few. We conducted this study to identify favorable factors for employment after transplantation. METHODS: Adult patients <65 yr of age who underwent renal transplantation between January 1, 2002 and December 31, 2007 were surveyed. Patients with graft survival <1 yr were excluded. We also tested their knowledge of Medicare coverage after transplantation. Data were analyzed using chi-squared and Fisher's exact tests. p-Value <0.05 was considered statistically significant. RESULTS: A 55% response rate was obtained where 56% of respondents were employed after transplantation. Race, marital status, previous transplant, and complicated post-operative course did not influence employment. Favorable factors include male gender (p=0.04), younger age (<40 [p=0.0003] or <50 yr [p<0.0001]), having ≥1 dependent (p=0.04), higher education (minimum high school degree [p=0.003] or some college [p=0.002]), live donor recipient (p=0.004), wait time <2 yr (p=0.03), dialysis <2 yr (p<0.0001) or pre-dialysis (p=0.04), and pre-transplantation employment (p<0.0001). Mean time for employment was 4.9±6.3 months (median three months). Common reasons for unemployment were disability (59%) and retirement (27%). Finally, 7% correctly responded that Medicare benefits end 36 months following transplantation. CONCLUSIONS: Potentially modifiable factors to improve employment are earlier referral and better education regarding Medicare eligibility.

A review of the United States experience with combined heart-liver transplantation.

Since first described by Starzl, combined heart and liver transplantation (CHLT) has been a relatively rare event, although utilization has increased in the past decade. This study was undertaken to review the United States experience with this procedure; UNOS data on CHLT was reviewed. CHLT was compared with liver transplantation alone and heart transplantation alone in terms of acute rejection within 12 months, graft survival, and patient survival. Survival was calculated according to Kaplan-Meier and Cox proportional hazards. Continuous variables were compared using Student's t-test and categorical variables with chi-squared. Between 1987 and 2010, there were 97 reported cases of CHLT in the United States. Amyloidosis was the most common indication for both heart (n = 26, 26.8%) and liver (n = 27, 27.8%) transplantation in this cohort. Liver graft survival in the CHLT cohort at 1, 5, and 10 years was 83.4%, 72.8%, and 71.0%, whereas survival of the cardiac allograft was 83.5%, 73.2%, and 71.5%. This was similar to graft survival in liver alone transplantation (79.4%, 71.0%, 65.1%; P = 0.894) and heart transplantation alone (82.6%, 71.9%, 63.2%; P = 0.341). CHLT is a safe and effective procedure, with graft survival rates similar to isolated heart and isolated liver transplantation.

Region 11 MELD Na exception prospective study.

INTRODUCTION: Hyponatremia complicates cirrhosis and predicts short term mortality, including adverse outcomes before and after liver transplantation. MATERIAL AND METHODS: From April 1, 2008, through April 2, 2010, all adult candidates for primary liver transplantation with cirrhosis, listed in Region 11 with hyponatremia, were eligible for sodium (Na) exception. RESULTS: Patients with serum sodium (SNa) less than 130 mg/dL, measured two weeks apart and within 30 days of Model for End Stage Liver Disease (MELD) exception request, were given preapproved Na exception. MELD Na was calculated [MELD + 1.59 (135-SNa/30 days)]. MELD Na was capped at 22, and subject to standard adult recertification schedule. On data end of follow-up, December 28, 2010, 15,285 potential U.S. liver recipients met the inclusion criteria of true MELD between 6 and 22. In Region 11, 1,198 of total eligible liver recipients were listed. Sixty-two (5.2%) patients were eligible for Na exception (MELD Na); 823 patients (68.7%) were listed with standard MELD (SMELD); and 313 patients (26.1%) received HCC MELD exception. Ninety percent of MELD Na patients and 97% of HCC MELD patients were transplanted at end of follow up, compared to 49% of Region 11 standard MELD and 40% of U.S.A. standard MELD (USA MELD) patients (p < 0.001); with comparable dropout rates (6.5, 1.6, 6.9, 9% respectively; p = 0.2). MELD Na, HCC MELD, Region 11 SMELD, and USA MELD post-transplant six-month actual patient survivals were similar (92.9, 92.8, 92.2, and 93.9 %, respectively). CONCLUSION: The Region 11 MELD Na exception prospective trial improved hyponatremic cirrhotic patient access to transplant equitably, and without compromising transplant efficacy.

Perioperative anticoagulation and antiplatelet therapy in renal transplant: is there an increase in bleeding complication?

BACKGROUND: Renal transplant recipients may have comorbidities requiring anticoagulation or antiplatelet therapy. While the effects of warfarin may be neutralized with plasma infusion, those of aspirin and clopidogrel are not easily reversible and may be associated with an increased risk of bleeding. We conducted this study to evaluate the risk of bleeding complications in patients receiving perioperative anticoagulation or antiplatelet therapy. METHODS: Medical records of patients who underwent renal transplantation from July 1, 2005 to April 30, 2009 were retrospectively reviewed. Patients receiving perioperative anticoagulation or antiplatelet therapy were identified. The incidence of reoperation, transfusion utilization and decrease in serum hemoglobin from pre-operative value (ΔHgb) were compared to those on no therapy. RESULTS: Of the 327 patients identified, 105 received pre-operative anticoagulation or antiplatelet therapy, 28 received therapy post-operatively, while 213 patients received no therapy. The incidence of reoperation, transfusion utilization and ΔHgb were not significantly increased with pre-operative anticoagulation or antiplatelet therapy. With post-operative heparin infusion, the incidence of reoperation and transfusion utilization were significantly increased (p values < 0.001). Patients with activated partial thromboplastin times (aPTT) >80 s experienced significant bleeding complications. CONCLUSION: A supratherapeutic aPTT with post-operative heparin infusion was associated with the greatest risk of bleeding complication.

Prophylaxis against de novo hepatitis B for liver transplantation utilizing hep B core (+) donors: does hepatitis B immunoglobulin provide a survival advantage?

Donor liver allografts with positive serology for hepatitis B core antibody [HBc (+)] have been increasingly used for liver transplantation. However, the optimal prophylactic regimen to prevent development of de novo hepatitis B has not been determined. To evaluate this, we screened United Network for Organ Sharing (UNOS) Standard Transplant Analysis and Research (STAR) registry data for adult recipients of HBc (+) organs who were HBsAg (-), and evaluated the effects of using prophylactic anti-viral therapies (HBIG and lamivudine) on patient and graft survival. Out of a total cohort of 958 patients transplanted since 2004, 61 received HBIG alone, 116 received lamivudine alone, 66 both, 509 neither and 206 were missing this information. Based on several multivariable Cox regression models, patients receiving HBIG therapy-only were observed to have a statistically significant (approximately 70%) reduction in risk of mortality compared with patients receiving lamivudine-only therapy [HR=0.29, 95% CI (0.10, 0.86), P=0.026], and a nonstatistically significant reduction in risk of graft failure. However, no graft failures were attributed to de novo hepatitis B, suggesting that any improved graft/patient survival possibly associated with HBIG therapy occurs independently of de novo hepatitis B virus (HBV) reduction. While this study cannot prove that HBIG therapy is protective for graft and patient survival after liver transplantation, these findings do highlight the need to further examine and study prophylactic use in recipients of HBc (+) donors.