The learning curve of deceased donor liver transplant during fellowship training.

Liver transplantation (LT) is a complex operation that most transplant surgeons learn in fellowship. Training varies as there is lack of objective data that can be used to standardize teaching. We performed a retrospective review of our adult LT database with aim of looking at fellow's experience. Using American Society of Transplant Surgery cutoff of, at least 45 LT during fellowship, data for first 45 LT were compared to LT 45-90. Fellow's cases were also clustered in sequential groups of 15 LT and analyzed to estimate the learning curve (LC). Comparison of LT 1-45 with LT 46-90 showed significantly lower total operative times (TOT) (324 vs. 344 min) and warm ischemia times (WIT) (28 vs. 31 min) in the 45-90 group. Rates of biliary complications (23.8% vs. 16.4%) and bile leaks alone (10.3% vs. 5.5%) were significantly higher for first 45 LT. Analysis of fellows experience in sequential clusters of 15 LT showed decreasing TOT, WIT, biliary complications and rates of unplanned return to the OR with progression of fellowship. This study validates the current ASTS requirement of at least 45 LT. LC generated using these data can help individualize training and optimize outcomes through identification of areas in need of improvement.

KDOQI Clinical Practice Guideline for Vascular Access: 2019 Update.

The National Kidney Foundation's Kidney Disease Outcomes Quality Initiative (KDOQI) has provided evidence-based guidelines for hemodialysis vascular access since 1996. Since the last update in 2006, there has been a great accumulation of new evidence and sophistication in the guidelines process. The 2019 update to the KDOQI Clinical Practice Guideline for Vascular Access is a comprehensive document intended to assist multidisciplinary practitioners care for chronic kidney disease patients and their vascular access. New topics include the end-stage kidney disease "Life-Plan" and related concepts, guidance on vascular access choice, new targets for arteriovenous access (fistulas and grafts) and central venous catheters, management of specific complications, and renewed approaches to some older topics. Appraisal of the quality of the evidence was independently conducted by using a Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach, and interpretation and application followed the GRADE Evidence to Decision frameworks. As applicable, each guideline statement is accompanied by rationale/background information, a detailed justification, monitoring and evaluation guidance, implementation considerations, special discussions, and recommendations for future research.

Development of immune response to tissue-restricted self-antigens in simultaneous kidney-pancreas transplant recipients with acute rejection.

Simultaneous kidney-pancreas transplantation (SKP Tx) is a treatment for end-stage kidney disease secondary to diabetes mellitus. We investigated the role of immune responses to donor human leukocyte antigens (HLA) and tissue-restricted kidney and pancreas self-antigens (KSAgs and PSAgs, respectively) in SKP Tx recipients (SKP TxRs). Sera collected from 39 SKP TxRs were used to determine de novo Abs specific for KSAgs (collagen-IV, Col-IV; fibronectin, FN) and PSAgs (insulin, islet cells, glutamic acid decarboxylase, and pancreas-associated protein-1) by ELISA. KSAg-specific IFN-γ, IL-17, and IL-10 cytokines were enumerated by ELISpot. Abs to donor HLA classes I and II were determined by Luminex assay. Abs to KSAgs and PSAgs were detectable in recipients with rejection compared with stable recipients (P<.05). Kidney-only rejection recipients had increased Abs against KSAgs compared with stable (P<.05), with no increase in Abs against PSAgs. Pancreas-only rejection recipients showed increased Abs against PSAgs compared to stable (P<.05), with no Abs against KSAgs. SKP TxRs with rejection showed increased frequencies of KSAg-specific IFN-γ and IL-17 with reduction in IL-10-secreting cells. SKP TxRs with rejection developed Abs to KSAgs and PSAgs demonstrated increased frequencies of kidney or pancreas SAg-specific IFN-γ and IL-17-secreting cells with reduced IL-10, suggesting loss of peripheral tolerance to SAgs.

Successful use of minimal incision superficialization technique for arteriovenous fistula maturation.

BACKGROUND: Successful cannulation is an important prerequisite for a functional arteriovenous fistula (AVF). Reasons for unsuccessful cannulation of an AVF are multifactorial and poorly evaluated. In our experience, a needle access segment (NAS) with a length of 10 cm, <5 mm deep from the skin surface, and >6 mm diameter assessed objectively using duplex Doppler ultrasound (DDUS) imaging, in a fistula with brachial artery flow >500 mL/min, permits consistent cannulation. This report provides observational data on the NAS of the outflow veins after fistula creation and a detailed long-term outcome on AVFs that needed superficialization of the NAS using minimal incision superficialization technique (MIST) to make them suitable for cannulation. This report is based on prospectively collected data with a longitudinal follow-up in a large patient cohort. METHODS: A prospective database was used to analyze consecutive patients undergoing AVF until the study end point. All patients underwent a protocol-based maturation evaluation using color DDUS imaging. Unsuitable NAS were surgically corrected using superficialization (by MIST or lipectomy) of deeply situated veins or NAS reconstruction. RESULTS: Between February 1, 2007, and May 31, 2013, 617 new AVF surgeries were performed. Outflow vein superficialization (MIST or lipectomy) or NAS reconstruction was necessary in 226 of 585 procedures (38.6%) included in this analysis. Of these, 162 (72%) were performed using MIST, 50 (22%) with a single long incision, and 14 (6%) using lipectomy technique. Technical success for MIST was 100%, and only two fistulae failed to mature. The vein depth of 9.2 ± 3.2 mm during initial vessel mapping was similar to the pre-MIST depth of 9.1 ± 3.8 mm. Depth of NAS improved to 3.1 ± 1.0 mm after MIST. The secondary patency after MIST at 6, 12, 24, 48, and 60 months was 98%, 93.3%, 88.1%, 83.3%, and 80.9%. During the 400.8 post-MIST functional fistula-years, only 0.63 procedures per year were required to maintain AVF patency. CONCLUSIONS: Our data suggest that maturation of AVFs using objective criteria based on DDUS provides an opportunity to identify NAS problems in outflow veins before cannulation. Most of the of the AVF outflow veins (71.7%) could be transposed or superficialized using MIST, with excellent long-term outcomes.

Randomized trial of a dry-powder, fibrin sealant in vascular procedures.

OBJECTIVE: Topical hemostats are important adjuncts for stopping surgical bleeding. The safety and efficacy of Fibrocaps, a dry-powder, fibrin sealant containing human plasma-derived thrombin and fibrinogen, was evaluated in patients undergoing vascular surgical procedures. METHODS: In this single-blind trial (clinicaltrials.gov: NCT01527357), adult patients were randomized 2:1 to Fibrocaps plus gelatin sponge (Fibrocaps) vs gelatin sponge alone. Results are presented for the patient subset undergoing vascular procedures with suture hole bleeding. The primary efficacy endpoint compared time to hemostasis (TTH) over 5 minutes. Safety follow-up continued to day 29. RESULTS: A total of 175 patients were randomized and treated (Fibrocaps, 117; gelatin sponge, 58). Patients were predominately male (69%) and underwent arterial bypass (81%), arteriovenous graft formation (9%), or carotid endarterectomy (9%). Fibrocaps significantly reduced TTH compared with gelatin sponge (hazard ratio [HR], 2.1; 95% confidence interval [CI], 1.5-3.1; median TTH, 2 minutes; 95% CI, 1.5-2.5 vs 4 minutes; 95% CI, 3.0-5.0; P < .002). Significant reductions were also observed in patients receiving concomitant antiplatelet agents alone (HR, 2.8; 95% CI, 1.0-7.4; P = .03; n = 33), anticoagulants alone (HR, 2.0; 95% CI, 1.0-4.0; P = .04; n = 43), or both antiplatelet agents and anticoagulants (Fibrocaps vs gelatin sponge, HR, 2.3; 95% CI, 1.2-4.3; P = .008; n = 65). Incidences of common adverse events (procedural pain, nausea, constipation) were generally comparable between treatment arms. Anti-thrombin antibodies developed in 2% of Fibrocaps-treated patients and no-gelatin-sponge patients. CONCLUSIONS: Fibrocaps, a ready-to-use, dry-powder fibrin sealant, was well-tolerated and reduced TTH in patients undergoing vascular procedures, including those receiving antiplatelet agents and/or anticoagulants, demonstrating its safety and usefulness as an adjunct to hemostasis.

Morbid obesity in liver transplant recipients adversely affects longterm graft and patient survival in a single-institution analysis.

OBJECTIVE: The effects of obesity in liver transplantation remain controversial. Earlier institutional data demonstrated no significant difference in postoperative complications or 1-year mortality. This study was conducted to test the hypothesis that obesity alone has minimal effect on longterm graft and overall survival. METHODS: A retrospective, single-institution analysis of outcomes in patients submitted to primary adult orthotopic liver transplantation was conducted using data for the period from 1 January 2002 to 31 December 2012. Recipients were divided into six groups by pre-transplant body mass index (BMI), comprising those with BMIs of <18.0 kg/m(2) , 18.0-24.9 kg/m(2) , 25.0-29.9 kg/m(2) , 30.0-35.0 kg/m(2) , 35.1-40.0 kg/m(2) and >40 kg/m(2) , respectively. Pre- and post-transplant parameters were compared. A P-value of <0.05 was considered to indicate statistical significance. Independent predictors of patient and graft survival were determined using multivariate analysis. RESULTS: A total of 785 patients met the study inclusion criteria. A BMI of >35 kg/m(2) was associated with non-alcoholic steatohepatitis (NASH) cirrhosis (P < 0.0001), higher Model for End-stage Liver Disease (MELD) score, and longer wait times for transplant (P = 0.002). There were no differences in operative time, intensive care unit or hospital length of stay, or perioperative complications. Graft and patient survival at intervals up to 3 years were similar between groups. Compared with non-obese recipients, recipients with a BMI of >40 kg/m(2) showed significantly reduced 5-year graft (49.0% versus 75.8%; P < 0.02) and patient (51.3% versus 78.8%; P < 0.01) survival. CONCLUSIONS: Obesity increasingly impacts outcomes in liver transplantation. Although the present data are limited by the fact that they were sourced from a single institution, they suggest that morbid obesity adversely affects longterm outcomes despite providing similar short-term results. Further analysis is indicated to identify risk factors for poor outcomes in morbidly obese patients.

The Venous Window Needle Guide, a hemodialysis cannulation device for salvage of uncannulatable arteriovenous fistulas.

BACKGROUND: Arteriovenous fistulas (AVFs) are recommended for hemodialysis access when possible. A noncannulatable but otherwise well functioning AVF leads to prolonged catheter dependency and frustration for the patient and the renal health care provider team. Difficult cannulation patients include obese individuals in whom cannulation sites are too deep, and others with vein segments that are short, tortuous, or otherwise difficult to palpate. The Venous Window Needle Guide for Salvage of AV Fistulae (SAVE) trial was designed to evaluate the efficacy and safety of the Venous Window Needle Guide (VWING; Vital Access Corp, Salt Lake City, Utah) device for salvage of such noncannulatable AVFs that are otherwise functional. METHODS: The SAVE study included patients with an established and otherwise mature AVF, in whom an additional procedure would otherwise be necessary to establish reliable cannulation. The VWING is a single-piece titanium device that allows repeated access of an AVF through a single puncture site (buttonhole technique). Inclusion criteria included mature AVFs 6.0 to 15.0 mm in depth with multiple failed attempts at cannulation or where the access could not be palpated. The devices were implanted subcutaneously and sutured to the anterior wall of the mature fistula. Study end points were reliable and successful cannulation and avoidance of adverse events during the 6-month follow-up, implant technical success, and clinical cannulation success. RESULTS: Enrollment included 54 patients at 11 trial sites with implantation of 82 VWING devices. Body mass index was 26 to 50 (median, 36), 40 (74%) patients were female, and age was 17 to 84 (median, 59) years. Forty (74%) individuals were diabetic. Thirty-three (61%) patients were white, 16 (30%) black, and 10 (18%) patients were Hispanic, Pacific Islander, or Native American. Three patients were excluded from data analysis for reasons unrelated to the device. Successful AVF access was achieved using the VWING in 49 (96%) of the 51 patients evaluated. The rate of device-related serious adverse events was 0.31 per patient-year; each event was resolved leaving the AVF functional. The rates of sepsis and study-related interventions were 0.04 and 0.65 per patient-year, respectively. There were no study-related deaths. One device was removed because of infection. The AVF survival rate at 6 months was 100%. The total number of study days was 9497 and the estimated number of device cannulations was 4238. CONCLUSIONS: The VWING was safe and effective in facilitating AVF cannulation for patients with an otherwise mature but noncannulatable fistula. Successful AVF access was achieved using the VWING in 49 (96%) of the 51 patients evaluated. The AVF survival rate at 6 months was 100%.

Ultrasound in preoperative evaluation for dialysis-access placement.

US vessel mapping for vascular access creation has evolved as standard practice in the preoperative evaluation of an ESRD patient. The best yield from this technology is when it is used to compliment physical examination and viewed in realtime by the operating physician. It is important to evaluate both arterial and venous systems during vessel mapping. While minimum diameters have been associated with an increased chance of maturation of an AV access, the quality of the vessel wall also plays an important role in maturation. US has a distinct advantage of being a noninvasive modality that can evaluate both structural and functional aspects of vessels that play an important role in access maturation.

Perioperative blood transfusion affects hepatitis C virus (HCV)-specific immune responses and outcome following liver transplantation in HCV-infected patients.

OBJECTIVES: Perioperative factors can affect outcomes of liver transplantation (LT) in recipients with hepatitis C virus (HCV) infection. This study was conducted to investigate whether the immunomodulatory effects of packed red blood cells (PRBC) and platelets administered in the perioperative period might affect immune responses to HCV and thus outcomes in LT recipients. METHODS: Data for a total of 257 HCV LT recipients were analysed. Data on clinical demographics including perioperative transfusion (during and within the first 24 h), serum cytokine concentration, HCV-specific interferon-γ (IFN-γ) and interleukin-17 (IL-17) producing cells, and outcomes including graft and patient survival were analysed. RESULTS: Patient survival was higher in HCV LT recipients who did not receive transfusions (Group 1, n = 65) than in those who did (Group 2, n = 192). One-year patient survival was 95% in Group 1 and 88% in Group 2 (P = 0.02); 5-year survival was 77% in Group 1 and 66% in Group 2 (P = 0.05). Group 2 had an increased post-transplant viral load (P = 0.032) and increased incidence of advanced fibrosis at 1 year (P = 0.04). After LT, Group 2 showed increased IL-10, IL-17, IL-1ß and IL-6, and decreased IFN-γ, and a significantly increased rate of IL-17 production against HCV antigen. Increasing donor age (P = 0.02), PRBC transfusion (P < 0.01) and platelets administration were associated with worse survival. CONCLUSIONS: Transfusion had a negative impact on LT recipients with HCV. The associated early increase in pro-HCV IL-17 and IL-6, with decreased IFN-γ, suggests that transfusion may be associated with the modulation of HCV-specific responses, increased fibrosis and poor transplant outcomes.

Organ allocation in pediatric renal transplants: is there an optimal donor?

The 2005 revised allocation scheme for pediatric renal transplantation made the decision of whether to transplant an available living-donor (LD) kidney or use a deceased-donor (DD) kidney controversial. The aim of this study was to examine kidney allograft utilization, sensitization, and outcomes of pediatric transplant recipients. Between January 2000 and December 2009, 91 consecutive pediatric kidney recipients (<20 yr) were transplanted. The LD (n = 38) and DD (n = 53) groups were similar in age, gender, dialysis status at transplant, warm ischemia time, and overall patient survival. LD recipients were more likely to be Caucasian (92 vs. 69%), receive older allografts (39 ± 10 vs. 23 ± 9 yr), and have fewer human leukocyte antigen (HLA) mismatches (3.3 ± 1.6 vs. 4.4 ± 1.5, p < 0.01 for all). Graft survival at one, three, and five yr post-transplant was longer for LD recipients (97%, 91%, 87% vs. DD 89%, 79%, 58%, respectively, p < 0.05). At the time of transplant, 17 (33%) DD recipients had an available LD (mean age 40 yr). A greater proportion of all patients were moderately (PRA 21-79%) sensitized post-transplant (p < 0.05). A multivariable analysis of graft survival indicated that the advantage in LD organs was likely due to fewer HLA mismatched in this group. Nonetheless, LD organs appear to provide optimal outcomes in pediatric renal transplants when considering the risk of becoming sensitized post-transplant complicating later use of the LD kidney.

Ultrasound as a tool for preoperative planning, monitoring, and interventions in dialysis arteriovenous access.

OBJECTIVE: The rising prevalence of end-stage renal disease has resulted in increasing focus on delivery of vascular access care for hemodialysis. Duplex Doppler ultrasound, with its unique ability to reliably evaluate both structural and functional aspects of the peripheral vessels, is the preferred imaging modality for access planning and follow-up. CONCLUSION: This article will review how ultrasound is currently used to evaluate patients pre-, intra-, and postoperatively for vascular access.

ASDIN white paper: Management of cephalic arch stenosis endorsed by the American Society of Diagnostic and Interventional Nephrology.

Brachiocephalic arteriovenous fistulas (AVF) makeup approximately one third of prevalent dialysis vascular accesses. The most common cause of malfunction with this access is cephalic arch stenosis (CAS). The accepted requirement for treatment of a venous stenosis lesion is ⩾50% stenosis associated with hemodynamically abnormalities. However, the correlation between percentage stenosis and a clinically significant decrease in access blood flow (Qa) is low. The critical parameter is the absolute minimal luminal diameter (MLD) of the lesion. This is the parameter that exerts the key restrictive effect on Qa and results in hemodynamic and functional implications for the access. CAS is the result of low wall shear stress (WSS) resulting from the effects of increased blood flow and the unique anatomical configuration of the CAS. Decrease in WSS has a linear relationship to increased blood flow velocity and neointimal hyperplasia exhibits an inverse relationship with WSS. The result is a stenotic lesion. The presence of downstream venous stenosis causes an inflow-outflow mismatch resulting in increased pressure within the access. Qa in this situation may be decreased, increased, or within a normal range. Over time, the increased intraluminal pressure can result in marked aneurysmal changes within the AVF, difficulties with cannulation and the dialysis treatment, and ultimately, increasing risk of access thrombosis. Complete characterization of the lesion both hemodynamically and anatomically should be the first step in developing a strategy for management. This requires both access flow measurement and angiographic imaging. Patients with CAS present a relatively broad spectrum as relates to both of these parameters. These data should be used to determine whether primary treatment of CAS should be directed toward the anatomical lesion (small MLD and low Qa) or the pathophysiology (large MLD and high Qa).

A novel technique of vascular anastomosis to prevent juxta-anastomotic stenosis following arteriovenous fistula creation.

OBJECTIVES: Juxta-anastomotic stenosis (JAS) is one of the predominant causes of arteriovenous fistula (AVF) failure, with the reported incidence as high as 65%. We hypothesized that technical modification to alter the outflow vein configuration using the novel piggyback Straight Line Onlay Technique (pSLOT) would prevent JAS and improve AVF maturation. METHODS: Intention-to-treat analysis of the outcomes of consecutive distal radiocephalic (RC) fistulas performed by a single operator with three different anastomotic techniques using a prospectively maintained database. Traditional end-to-side technique (ETS), side-to-side straight-line onlay technique (SLOT, STS) and pSLOT in RC AVF created in 125 consecutive patients between 1/2004 and 12/2007 were compared. AVF maturation was evaluated by ultrasonography at 4 to 6 weeks and use for dialysis. RESULTS: The mean age of the study group was 53.1 ± 20.7 years, the male-to-female ratio was 61:64, and the races studied were African American (66; 52.8%) and Caucasian (54; 43.2%). The primary disease for renal failure was hypertension (54; 43.2%) and diabetes (51; 40.8%). Brachial artery flow at maturation was 1103 ± 531 mL/min. Incidence of early JAS was 9.8% and late 14.6%. The clinico-demographic variables between ETS (n = 57), STS (n = 12), and pSLOT (n = 54) were similar. The median follow-up between three groups: ETS (19 months), STS (12 months), and pSLOT (19 months; P = .1), was similar. There was a significant decrease in JAS development in pSLOT patients (P = .04). pSLOT patients also revealed decreased overall fistula failure (ETS 40.3%, STS 33.3%, pSLOT 16.7%; P = .01). CONCLUSIONS: There was significant reduction in JAS and improvement in AVF maturation with pSLOT. This study provides evidence highlighting the role of outflow vein configuration in AVF maturation. Minimal alteration of vein wall configuration and avoidance torsion using pSLOT technique improves AVF maturation.

Safety and efficacy of local periadventitial delivery of sirolimus for improving hemodialysis graft patency: first human experience with a sirolimus-eluting collagen membrane (Coll-R).

BACKGROUND: Neointimal hyperplasia causes a high rate of hemodialysis synthetic graft failure. Thus, therapies that inhibit neointimal hyperplasia are urgently needed. The Coll-R is a sirolimus-eluting collagen matrix designed for intra-operative perivascular implantation around the graft-venous anastomosis. Sirolimus is an anti-proliferative drug that has proven clinical utility in suppressing neointimal tissue growth in coronary artery disease when delivered locally to the vascular wall by an endovascular drug eluting stent. METHODS: A cohort of 12 chronic hemodialysis patients underwent surgical placement of 13 polytetrafluoroethylene grafts + Coll-R and were followed for up to 24 months. The primary endpoint was safety (freedom from device related adverse events). Secondary endpoints were pharmacokinetics of sirolimus release, success of Coll-R implantation and primary unassisted graft patency. RESULTS: There were no technical failures, infections, vascular anastomotic or wound-healing problems. Whole blood sirolimus levels rose to a mean peak of 4.8 ng/mL at 6 h and fell to <1 ng/mL at 1 week (n = 5). Twelve and 24-month primary unassisted patencies were 76 and 38%, respectively, and the thrombosis rate was 0.37/patient-year. CONCLUSIONS: Perivascular implantation of the Coll-R during graft surgery safely delivered sirolimus to the vascular wall. Systemic sirolimus levels were sub-therapeutic for immunosuppression. This small first-in-human study supports the concept that the Coll-R can safely deliver sirolimus to the graft-venous anastomosis. Safety and patency in this small study were sufficiently encouraging to justify randomized controlled trials to further test the efficacy of the Coll-R.

Utilization of hepatitis B core antibody-positive donor liver grafts.

BACKGROUND: The inclusion of hepatitis B core antibody-positive (HBcAb+) liver donors is a strategy utilized to increase organ availability. This study examined HBcAb+ transplantation practices to identify specific factors influencing outcomes. METHODS: Twenty-five HBcAb+ liver transplants were identified retrospectively among 868 adult transplants performed between 1 January 1997 and 31 December 2009. Twelve (48%) recipients had hepatitis C and five (20%) had hepatitis B. Patient and donor demographics, preoperative morbidity, transplant data and outcomes were examined. Statistical analysis was completed using Student's t-test or the Kaplan-Meier method. A P-value of <0.05 was considered significant. RESULTS: There was no difference in age, body mass index or comorbidities between HBcAb+ liver recipients and control subjects. Model for End-stage Liver Disease (MELD) scores of >30 were significantly more frequent in HBcAb+ liver recipients (32% vs. 15%; P= 0.04). All patients received immunoglobulin and longterm antiviral therapy as prophylaxis against graft hepatitis B resurgence. No patients who received HBcAb+ livers developed hepatitis B infection on follow-up. Overall survival at 30 days, 1 year and 5 years in HBcAb+ liver recipients was 92%, 74% and 74%, respectively, compared with 96%, 89% and 76%, respectively, in the control group (P= not significant, log-rank test). All except one of the deaths in the HBcAb+ liver recipient group occurred within 90 days postoperatively and in patients with MELD scores >30. CONCLUSIONS: The practice of transplanting HBcAb+ grafts incurs low risk for infection using current methods of prophylaxis. The highest mortality risk was in the early postoperative period, specifically in patients with very high MELD scores. This probably reflects the practice of using positive serology grafts in emergent situations.

Immune response to extracellular matrix collagen in chronic hepatitis C-induced liver fibrosis.

Hepatitis C virus (HCV) infection and its recurrence after orthotopic liver transplantation (OLT) are associated with the remodeling of extracellular matrix (ECM) components [particularly collagen (Col)], which leads to fibrosis. Our aim was to determine whether the development of antibodies (Abs) to self-antigen Col in HCV-infected patients correlates with the fibrosis stage and the peripheral cytokine response. Patients with chronic HCV infection, patients with HCV recurrence after OLT who had undergone a biopsy procedure, and healthy control subjects were enrolled. The HCV subjects (n = 70) were stratified as follows: (1) a non-OLT group without fibrosis (Scheuer stages 0-2), (2) a non-OLT group with fibrosis (Scheuer stages 3-4), (3) a post-OLT group without fibrosis (Scheuer stages 0-2), and (4) a post-OLT group with fibrosis (Scheuer stages 3-4). Serum samples were analyzed for Abs against Col1, Col2, Col4, Col5, and vimentin with enzyme-linked immunosorbent assays. Serum levels of cytokines were measured with multiplex bead immunoassays. The levels of Abs to Col1 were higher in the fibrosis groups versus the no-fibrosis groups and the controls for both non-OLT patients (P < 0.001) and post-OLT patients (P = 0.01). There were increased levels of Abs to Col2, Col4, Col5, and vimentin in the non-OLT fibrosis group (Col2, P = 0.0001; Col4, P = 0.122; Col5, P < 0.0001; vimentin, P = 0.36) and in the post-OLT fibrosis group (Col2, P = 0.006; Col4, P = 0.19; Col5, P < 0.0001; vimentin, P = 0.24) in comparison with the no-fibrosis groups. The non-OLT and post-OLT fibrosis groups demonstrated significantly higher T helper 2 (T(h) 2) and T helper 17 (T(h) 17) cytokine levels and lower T helper 1 cytokine levels in comparison with the no-fibrosis groups. Our results demonstrate that in HCV-infected patients, the levels of Abs to ECM Col1, Col2, and Col5 positively correlate with liver fibrosis, which is associated with a predominantly T(h) 2 and T(h) 17 cytokine profile.

Contribution of inflow artery to observed flow in a vascular access: A computational fluid dynamic modeling study of an arteriovenous fistula circuit.

INTRODUCTION: The volume of blood flowing through the vascular access is an important parameter necessary to provide adequate dialysis for a functional arteriovenous fistula. Higher blood flows are seen in arteriovenous access that receive inflow from larger arteries such as brachial or axillary compared to those based on medium-caliber radial or ulnar arteries. We hypothesized that an anatomic difference in the length and the diameter of the artery is an important determinant of the flow volume in arteriovenous fistula created at different anatomic locations. METHODS: Using computational fluid dynamics, we evaluated the contribution of the length and diameter of inflow artery on simulations performed with geometric models constructed to represent arteriovenous fistula circuits. Lengths and diameters of the inflow artery were altered to mimic arteriovenous fistula created at various locations of the upper extremity with standard and variant anatomy. RESULTS: Models of arteriovenous fistula created with variable lengths and diameters of the inflow artery suggest that the length of the vessel has an inverse linear relationship and the diameter has a direct linear relationship to flow volume. CONCLUSION: Computational fluid dynamic modeling of arteriovenous fistula can be used to understand the physiologic basis of clinical observations of function. Evaluation of the effect of inflow artery length and diameter helps explain the higher flows seen in arteriovenous fistula created using large caliber arteries for inflow. Computational fluid dynamic modeling helps operators understand the contributions of inflow artery in access function and can guide anastomotic site selection.

Novel Method of Evaluating Liver Transplant Surgery Fellows Using Objective Measures of Operative Efficiency and Surgical Outcomes.

BACKGROUND: The majority of liver transplantations (LTs) in North America are performed by transplant surgery fellows with attending surgeon supervision. Although a strict case volume requirement is mandatory for graduating fellows, no guidelines exist on providing constructive feedback to trainees during fellowship. STUDY DESIGN: A retrospective review of all adult LTs performed by abdominal transplant surgery fellows at a single American Society of Transplant Surgeons-accredited academic institution from 2005 to 2019 was conducted. Data from the most recent 5 fellows were averaged to generate reference learning curves for 8 variables representing operative efficiency (ie total operative time, warm ischemia time, and cold ischemia time) and surgical outcomes (ie intraoperative blood loss, unplanned return to the operating room, biliary complication, vascular complication, and patient/graft loss). Data for newer fellows were plotted against the reference curves at 3-month intervals to provide an objective assessment measure. RESULTS: Three hundred and fifty-two adult LTs were performed by 5 fellows during the study period. Mean patient age was 56 years; 67% were male; and mean Model for End-Stage Liver Disease score at transplantation was 22. For the 8 primary variables, mean values included the following: total operative time 330 minutes, warm ischemia time 28 minutes, cold ischemia time 288 minutes, intraoperative blood loss 1.59 L, biliary complication 19.6%, unplanned return to operating room 19.3%, and vascular complication 2.3%. A structure for feedback to fellows was developed using a printed report card and through in-person meetings with faculty at 3-month intervals. CONCLUSIONS: Comparative feedback using institution-specific reference curves can provide valuable objective data on progression of individual fellows. It can aid in the timely identification of areas in need of improvement, which enhances the quality of training and has the potential to improve patient care and transplantation outcomes.

Incisional hernia after liver transplantation: Risk factors, management strategies and long-term outcomes of a cohort study.

INTRODUCTION: Incisional hernias (IH) develop in up to 40% of liver transplant (LT) recipients and can contribute to considerable morbidity. MATERIALS AND METHODS: A single center retrospective review of a prospectively maintained LT database was conducted to identify all patients diagnosed with IH after LT during a 13-year study period (2003-2015). Analyzed data included patient demographics, LT details, incidence and timing of IH, risk factors, management strategies and long-term outcomes. RESULTS: During the 13-year study period, IH was diagnosed in 16.7% (163/976) of LT recipients after a median of 19.6 months (range 6.7-49.5 months) from transplant surgery. Identified risk factors for developing IH included male gender (p < 0.001) while acute cellular rejection (ACR) was found to be negatively associated with the risk of developing IH (p = 0.014). Acute incarceration/strangulation was seen in 4 patients with IH while the remaining (n = 159) presented with non-emergent symptoms. Surgical repair was undertaken in 70/163 (43%) IH patients after medical optimization when possible (open repair 83%, mesh use 90%). IH recurrence rate was 14.3% (10/70) with comparable rates in no-mesh and with-mesh repairs (42.9% vs. 11.3%; p = 0.057) and open (15.8%) and laparoscopic (9.1%) approaches (p = 0.68). CONCLUSION: IH is a late complication following LT and male gender is a consistent predictive marker. Acute presentation is infrequent and elective repair can be planned in most patients allowing for risk factor optimization to ensure promising long-term outcomes.