Citations

Although the consequences of implantation of a large whole liver graft into a small recipient such as compression and compromise of graft perfusion are well known, no accepted measure to aid in donor‐to‐recipient size matching exists. Donor liver graft and recipient native liver weights as well as donor and recipient size and amount of ascites were investigated in 1953 patients who underwent liver transplantation using deceased donor grafts between January 2002 and July 2013. We used a previously described formula for liver resections (standardized total liver volume [sTLV] = –794.41 + 1267.28 × body surface area [m2]) for calculating sTLV, in the current cohort of deceased liver donors. Early allograft dysfunction (EAD) and graft survival were the primary outcome measures. The formula for calculating sTLV for liver resections was validated as an accurate predictor of liver volume in the current cohort of deceased liver donors (r2 = 0.45;P < 0.001). A cutoff point of sTLV ratio ≥ 1.25 was determined through receiver operating characteristic curves, and patients were dichotomized into 2 groups. In the sTLV ratio ≥ 1.25 group, 50% of patients developed EAD compared to 25% of patients in the sTLV ratio < 1.25 group (P < 0.001). The proportion of patients developing graft failure within 90 days was 9.6% in the sTLV ratio ≥ 1.25 group and 5.4% in the sTLV ratio < 1.25 group (P = 0.045). This study validates the use of the sTLV for prediction of actual donor liver weight in the transplant setting. Using this formula, donors with a calculated sTLV size ratio ≥ 1.25 have an increased risk of EAD and therefore caution should be used when that value is exceeded. This adjusted size ratio can be used as a decision aid when considering donor and recipient matching with potential liver organ offers.Liver Transpl 21:1471‐1477, 2015. © 2015 AASLD.

AbstractGraft‐versus‐host disease (GVHD) is a rare, fatal complication following orthotopic liver transplantation (OLT). To date, several risk factors have been proposed, but reports on these factors have been inconclusive. This is a retrospective, case–control study of prospectively collected data from 2775OLTs performed at our institution. Eight cases ofGVHDafterOLTwere diagnosed on the basis of the patient's clinical characteristics, and the findings were confirmed with skin and colonic biopsies. Each case was matched to three controls based on the diagnosis of liver disease, recipient's age, and blood group. Univariate and multivariate analyses were performed to identify risk factors associated with the development ofGVHDafterOLT. The univariate and multivariate analyses identified two main risk factors associated with development ofGVHDinOLTrecipients, a difference between recipient and donor age of >20 yr, and any human leukocyte antigen classImatches. Taking these two risk factors into consideration while matching prospective donors and recipients may reduce further incidence ofGVHDinOLTpatients. However, further studies are recommended to validate these findings.

Flex Tip Comparative AblationIntroductionNext‐generation catheters have been developed to reduce irrigation volume and preserve power delivery. A novel design uses a flexible tip (FlexAbility™ catheter) that directs flow to the contact surface. Because of recent safety issues with new catheters, we undertook a study in a canine heart with 3 irrigated catheters to compare efficacy and safety.MethodsEndocardial ablation was performed by 2 independent operators in 12 anesthetized canines with the FlexAbility (St. Jude Medical), ThermoCool™ (Biosense Webster), and ThermoCool™ SF (Biosense Webster) catheters. Endocardial RF lesions were delivered with each catheter in all 4 chambers of each animal for 52 ± 16 seconds. Each chamber was randomized to receive ablation from one catheter with recording of safety events. Cardiac pathology was performed with triphenyl tetrazolium chloride stain.ResultsAverage lesion dimensions were not significantly different between the 3 catheters. FlexAbility™ demonstrated a lower risk of steam pops relative to ThermoCool SF (P‐value = 0.013) despite equal mean power and radiofrequency time. High‐temperature generator shutdowns were observed with FlexAbility™ but not with either ThermoCool catheter. High‐temperature shutdowns were associated with larger average impedance drops (28.5 ohms vs. 19 ohms) without compromising lesion size.ConclusionsThe FlexAbility™ tip is safe and effective with no significant difference in lesion sizes compared to both standard ThermoCool and ThermoCool SF. FlexAbility™ has a significantly lower risk of steam pops compared to ThermoCool SF in a beating heart as defined predominantly by an abrupt rise of impedance.

Femoral bone loss is frequently encountered during revision total hip arthroplasty. The quality and quantity of remaining bone helps determine the best method for reconstruction. Extensively porous-coated cylindrical stems or titanium fluted tapered devices that achieve fixation in the diaphysis have both demonstrated excellent long-term survivorship. Titanium fluted tapered stems with a modular proximal body allow for more accurate leg length, offset, and version adjustments independent of the distal stem which may optimise hip biomechanics. Intraoperative fractures are more common with cylindrical stems and subsidence with tapered stems, particularly monoblock designs and in both dislocation continues to be one of the most common postoperative complications. In salvage situations in which an ectatic femoral canal is unable to support an uncemented device, impaction bone grafting, allograft-prosthetic composite, or a segmental proximal femoral replacement may be required.

Anoctamin 1 (Ano1; TMEM16A) is a Ca2+-activated Cl− channel (CACC) expressed in interstitial cells of Cajal. The mechanisms by which Ca2+ regulates Ano1 are incompletely understood. In the gastrointestinal tract, Ano1 is required for normal slow wave activity and is involved in regulating cell proliferation. Splice variants of Ano1 have varying electrophysiological properties and altered expression in disease states. Recently, we identified a transcript for human Ano1 containing a novel exon-“exon 0” upstream of and in frame with exon 1. The electrophysiological properties of this longer Ano1 isoform are unknown. Our aim was to determine the functional contribution of the newly identified exon to the Ca2+ sensitivity and electrophysiological properties of Ano1. Constructs with [Ano1(+0)] or without [Ano1(−0)] the newly identified exon were transfected into human embryonic kidney-293 cells. Voltage-clamp electrophysiology was used to determine voltage- and time-dependent parameters of whole cell Cl− currents between isoforms with varying concentrations of intracellular Ca2+, extracellular anions, or Cl− channel inhibitors. We found that exon 0 did not change voltage sensitivity and had no impact on the relative permeability of Ano1 to most anions. Ano1(+0) exhibited greater changes in current density but lesser changes in kinetics than Ano1(−0) in response to varying intracellular Ca2+. The CACC inhibitor niflumic acid inhibited current with greater efficacy and higher potency against Ano1(+0) compared with Ano1(−0). Likewise, the Ano1 inhibitor T16Ainh-A01 reduced Ano1(+0) more than Ano1(−0). In conclusion, human Ano1 containing exon 0 imparts its Cl− current with greater sensitivity to intracellular Ca2+ and CACC inhibitors.

Osteoporosis is characterized by bony material loss and decreased bone strength leading to a significant increase in fracture risk. Patient-specific quantitative computed tomography (QCT) finite element (FE) models may be used to predict fracture under physiological loading. Material properties for the FE models used to predict fracture are obtained by converting grayscale values from the CT into volumetric bone mineral density (vBMD) using calibration phantoms. If there are any variations arising from the CT acquisition protocol, vBMD estimation and material property assignment could be affected, thus, affecting fracture risk prediction. We hypothesized that material property assignments may be dependent on scanning and postprocessing settings including voltage, current, and reconstruction kernel, thus potentially having an effect in fracture risk prediction. A rabbit femur and a standard calibration phantom were imaged by QCT using different protocols. Cortical and cancellous regions were segmented, their average Hounsfield unit (HU) values obtained and converted to vBMD. Estimated vBMD for the cortical and cancellous regions were affected by voltage and kernel but not by current. Our study demonstrated that there exists a significant variation in the estimated vBMD values obtained with different scanning acquisitions. In addition, the large noise differences observed utilizing different scanning parameters could have an important negative effect on small subregions containing fewer voxels.

AbstractRobotic surgical techniques are now being applied in the setting of retroperitoneal lymphadenectomy (RPLND) for testicular cancer. While laparoscopic RPLND has not been widely accepted, reports of robot assisted RPLND (RARPLND) are emerging. This manuscript will review the application of RPLND for testicular cancer, evolution of minimally invasive techniques, the controversies, and current status of RARPLND. J. Surg. Oncol. 2015;112:736–740. © 2015 Wiley Periodicals, Inc.