Development of Clinical Algorithm Utilizing Vibration-Controlled Transient Elastography to Detect Advanced Hepatic Fibrosis in Liver Transplant Recipients

INTRODUCTION

Vibration-controlled transient elastography (VCTE) based liver stiffness measurement (LSM) is an excellent 'rule-out' test for advanced hepatic fibrosis in liver transplant (LT) recipients, however, its ability to 'rule-in' the disease is suboptimal. The study aimed to improve diagnostic performance of LSM in LT recipients.

METHODS

Adult LT recipients with a liver biopsy and VCTE were included (N = 150). Sequential covering analysis was performed to create rules to identify patients at low or high risk for advanced fibrosis (stage 3-4).

RESULTS

Advanced hepatic fibrosis was excluded in patients with either LSM < 7.45 kPa (n = 72) or 7.45 ≤ LSM < 12.1 kPa and time from LT < 5.6 years (n = 25). Conversely, likelihood of advanced fibrosis was 95% if patients had LSM > 14.1 and controlled attenuation parameter > 279 dB/m (n = 21). Thus, 118 (79%) were correctly identified and 32 (21%) would have required a biopsy to establish the diagnosis. Compared to previously established LSM based cutoff values of 10.5 kPa (Youden index) and 13.3 kPa (maximized specificity), the false positive rates of sequential covering analysis was 1% compared to 16.5% with LSM ≥ 10.5 kPa and 8.3% with LSM ≥ 13.3 kPa. The true positive rates were comparable at 87% for sequential covering analysis, 93% for LSM ≥ 10.5 kPa and 83% for LSM ≥ 13.3 kPa.

CONCLUSION

The proposed clinical sequential covering analysis allows for better risk stratification when evaluating for advanced fibrosis in LT recipients compared to LSM alone. Additional efforts are necessary to further reduce the number of patients with indeterminate results in whom a liver biopsy may be required.

Geographic disparities in access to liver transplant for advanced cirrhosis: Time to ring the alarm!

Decompensated cirrhosis and hepatocellular cancer are major risk factors for mortality worldwide. Liver transplantation (LT), both live-donor LT or deceased-donor LT, are lifesaving, but there are several barriers toward equitable access. These barriers are exacerbated in the setting of critical illness or acute-on-chronic liver failure. Rates of LT vary widely worldwide but are lowest in lower-income countries owing to lack of resources, infrastructure, late disease presentation, and limited donor awareness. A recent experience by the Chronic Liver Disease Evolution and Registry for Events and Decompensation consortium defined these barriers toward LT as critical in determining overall survival in hospitalized cirrhosis patients. A major focus should be on appropriate, affordable, and early cirrhosis and hepatocellular cancer care to prevent the need for LT. Live-donor LT is predominant across Asian countries, whereas deceased-donor LT is more common in Western countries; both approaches have unique challenges that add to the access disparities. There are many challenges toward equitable access but uniform definitions of acute-on-chronic liver failure, improving transplant expertise, enhancing availability of resources and encouraging knowledge between centers, and preventing disease progression are critical to reduce LT disparities.

'Burn and Push' technique: A novel robotic liver parenchymal transection technique

BACKGROUND

Liver parenchymal transection during robotic liver resection (RLR) remains a significant challenge due to the limited range of specialised instruments. This study introduces our 'Burn and Push' technique as a novel approach to address these challenges.

METHODS

A retrospective analysis was conducted on 20 patients who underwent RLR using the 'Burn and Push' technique at Virginia Commonwealth University Health System from November 2021 to August 2023. The study evaluated peri- and post-operative outcomes.

RESULTS

The median operation time was 241.5 min (range, 90-620 min), and the median blood loss was 100 mL (range, 10-600 mL). Major complications occurred in one case, with no instances of postoperative bleeding, bile leak, or liver failure.

CONCLUSIONS

The 'Burn and Push' technique is a viable and efficient alternative for liver parenchymal transection in RLR. Further research with larger sample sizes and consideration of the learning curve is necessary to validate these findings.

Robotic management of primary cholecystoduodenal fistula: A case report and brief literature review

BACKGROUND

Cholecystoduodenal fistula (CDF) arises from persistent biliary tree disorders, causing fusion between the gallbladder and duodenum. Initially, open resection was common until laparoscopic fistula closure gained popularity. However, complexities within the gallbladder fossa yielded inconsistent outcomes. Advanced imaging and robotic surgery now enhance precision and detection.

METHOD

A 62-year-old woman with chronic cholangitis attributed to cholecystoduodenal fistula underwent successful robotic cholecystectomy and fistula closure.

RESULTS

Postoperatively, the symptoms subsided with no complications during the robotic procedure. Existing studies report favourable outcomes for robotic cholecystectomy and fistula closure.

CONCLUSIONS

Our case report showcases a rare instance of successful robotic cholecystectomy with CDF closure. This case, along with a review of previous cases, suggests the potential of robotic surgery as the preferred approach, especially for patients anticipated to face significant laparoscopic morbidity.

Defect interactions in a two-dimensional sheared lamellar mesophase

The interaction between two edge dislocations in a sheared lyotropic lamellar liquid-crystalline medium is examined. The model is a mesoscale hydrodynamic model based on a free-energy functional that is minimised for a sinusoidal concentration modulation coupled with concentration and momentum equations. The defect dynamics are analysed as a function of the system size and the Ericksen number, the ratio of the shear stress and the characteristic free-energy density for deformation. Three different regimes are observed as the Ericksen number is increased when the edge dislocations are sheared towards each other, such that there is compression of layers between the defects: (a) defect motion that reduces the cross-stream separation till there is a steady spacing with plug flow between the defects, (b) defect attraction and cancellation resulting in a well-aligned state, and (c) defect creation due to a compressional instability between the defects resulting in an increase in the disorder. When the edge dislocations are sheared away from each other, such that there is extension of the layers between the defects, two distinct regimes are observed as the Ericksen number is increased: (a) bending of layers and a plug flow between the defects at their initial separation, and (b) buckling of the layers leading to creation of more defects and a dynamical steady state between defect creation and cancellation. These regimes are found to be robust for different values of the system size, from 32 to 128 layers, and for different values of the dimensionless groups that characterise the ratio of mass/momentum convection and diffusion.

Impact of Liver Transplantation on Adipose Tissue Compartments and Its Association With Metabolic Sequela

BACKGROUND

Loss of skeletal muscle can be accompanied by an increase in adipose tissue leading to sarcopenic obesity. There are limited data on how liver transplantation (LT) might impact adipose tissue compartments, particularly among patients with metabolically active disease, such as nonalcoholic steatohepatitis (NASH) and subsequent metabolic sequela.

METHODS

Skeletal muscle, visceral adipose tissue (VAT), and subcutaneous adipose tissue (SAT) were measured using cross-sectional imaging performed in 190 patients pre-LT, 6 mo post-LT and 12 mo post-LT. Changes in adipose tissue and their impact on metabolic diseases were determined in patients transplanted for NASH versus non-NASH.

RESULTS

Skeletal muscle, VAT, and SAT were similar in patients with NASH and non-NASH pre-LT despite a higher burden of metabolic diseases in patients with NASH. Following LT, no significant differences between skeletal muscle and SAT were observed in the entire cohort and among patients with NASH (versus non-NASH). LT recipients with the highest muscle mass pre-LT were at the greatest risk for muscle loss post-LT. A time-dependent increase in VAT was noted post-LT, which was more robust among patients with a history of NASH cirrhosis. In adjusted multivariate analysis, NASH versus non-NASH was a strong predictor of post-LT increase in VAT (β-coefficient 3.00, P  = 0.04). Pre-LT VAT was an independent predictor of post-LT serum triglycerides (β-coefficient 5.49 ± 2.78, P  = 0.05) and low-density lipoprotein cholesterol (β-coefficient 1.80 ± 0.75, P  = 0.02). A trend between pre-LT VAT and diabetes was noted but did not reach statistical significance.

CONCLUSIONS

VAT but not SAT increases rapidly after LT, especially among patients transplanted for NASH cirrhosis and predicts future metabolic burden.

Liver transplantation for post-COVID-19 cholangiopathy: A case series

BACKGROUND

Post-COVID-19 cholangiopathy is an emerging cholestatic liver disease observed in patients recovering from severe COVID-19 infection. Its prognosis is poor, necessitating liver transplantation in some cases. This study aimed to investigate the outcomes of liver transplantation for post-COVID-19 cholangiopathy.

METHODS

Seven patients who underwent liver transplantation for post-COVID-19 cholangiopathy at three institutions between 2020 and 2022 were included in this retrospective multi-center case series.

RESULTS

At the time of initial COVID-19 infection, all patients developed acute respiratory distress syndrome, and six patients (86%) required ICU admission. Median time intervals from the initial COVID-19 diagnosis to the diagnosis of post-COVID-19 cholangiopathy and liver transplantation were 4 and 12 months, respectively. Four patients underwent living donor liver transplantation, and three patients underwent deceased donor liver transplantation. The median MELD score was 22 (range, 10-38). No significant intraoperative complications were observed. The median ICU and hospital stays were 2.5 and 12.5 days, respectively. One patient died due to respiratory failure 5 months after liver transplantation. Currently, the patient and graft survival rate is 86% at a median follow-up of 11 months.

CONCLUSIONS

Liver transplantation is a viable option for patients with post-COVID-19 cholangiopathy with acceptable outcome. Timely identification of this disease and appropriate management, including evaluation for liver transplantation, are essential.

Domino Liver Transplantation for Unresectable Colon Cancer Liver Metastasis From a Donor With Heterozygous Familial Hyperlipidemia: A Case Report

Liver transplantation (LT) is a potential curative treatment for unresectable colorectal cancer liver metastasis (CRLM). Familial hypercholesterolemia (FH) is an inherited condition characterized by elevated low-density lipoprotein cholesterol (LDL-C) levels. Liver transplantation is offered for selected cases, and an explanted liver can be used as a domino graft. We report the first report of domino LT for unresectable CRLM using a liver from a patient with heterozygous FH. The domino donor was a 30-year-old female with a history of heterozygous FH. She had failed medical therapies for FH, including plasmapheresis; therefore, she underwent living donor LT as a treatment for FH. The explanted liver was transplanted to the domino recipient. She has been doing well with normal LDL-C levels. The domino recipient was a 44-year-old female with a history of stage 4 sigmoid cancer with liver metastases, for which she underwent laparoscopic sigmoid colectomy and right hepatectomy. She developed unresectable lesions in the remnant left lobe, which were controlled well with chemotherapy; therefore, she underwent domino LT. She is doing well without recurrence at the 31-month follow-up. Domino LT from a donor with heterozygous FH is feasible for strictly selected patients with unresectable CRLM.

Anesthesia and Critical Care for the Prediction and Prevention for Small-for-size Syndrome: Guidelines from the ILTS-iLDLT-LTSI Consensus Conference

BACKGROUND

During the perioperative period of living donor liver transplantation, anesthesiologists and intensivists may encounter patients in receipt of small grafts that puts them at risk of developing small for size syndrome (SFSS).

METHODS

A scientific committee (106 members from 21 countries) performed an extensive literature review on aspects of SFSS with proposed recommendations. Recommendations underwent a blinded review by an independent expert panel and discussion/voting on the recommendations occurred at a consensus conference organized by the International Liver Transplantation Society, International Living Donor Liver Transplantation Group, and Liver Transplantation Society of India.

RESULTS

It was determined that centers with experience in living donor liver transplantation should utilize potential small for size grafts. Higher risk recipients with sarcopenia, cardiopulmonary, and renal dysfunction should receive small for size grafts with caution. In the intraoperative phase, a restrictive fluid strategy should be considered along with routine use of cardiac output monitoring, as well as use of pharmacologic portal flow modulation when appropriate. Postoperatively, these patients can be considered for enhanced recovery and should receive proactive monitoring for SFSS, nutrition optimization, infection prevention, and consideration for early renal replacement therapy for avoidance of graft congestion.

CONCLUSIONS

Our recommendations provide a framework for the optimal anesthetic and critical care management in the perioperative period for patients with grafts that put them at risk of developing SFSS. There is a significant limitation in the level of evidence for most recommendations. This statement aims to provide guidance for future research in the perioperative management of SFSS.

Robotic hepatectomy and cholecystectomy in the management of intraductal papillary mucinous neoplasm of the biliary tract: A case report and literature review

BACKGROUND

In the Western Hemisphere, Intraductal papillary mucinous neoplasm of the biliary tract (IPMN-B) is a rare lesion with uncertain aetiology. This report outlines a scarcely documented instance of IPMN-B treated using robotic hepatectomy and cholecystectomy supplemented with intraoperative imagery aimed at informing future robotic procedures.

METHODS

A healthy person with acute cholangitis symptoms underwent diagnostic imaging followed by successful robotic hepatectomy and cholecystectomy. Pathological examination confirmed IPMN-B.

RESULTS

The patient was consulted regarding the proposed procedure of robotic left hepatectomy, cholecystectomy, and potential hepaticojejunostomy, to which she provided consent. Subsequent surgical intervention resulted in clear margins for malignancy, and the patient recovered without complications.

CONCLUSIONS

This case emphasises the importance of early diagnosis and intervention in managing IPMN. The use of a robotic approach, specifically through robotic left hepatectomy combined with cholecystectomy, offers minimally invasive surgery that provides exceptional visualisation and precise control.

The relationship between structure and rheology in a three-dimensional sheared lamellar mesophase

The evolution of a lamellar mesophase from an initially disordered state under shear is examined using simulations of a mesoscale model based on a concentration field ψ that distinguishes the hydrophilic and hydrophobic components. The Landau-Ginzburg free-energy functional is augmented by a term that is minimised for sinusoidal modulations in the concentration field with wavelength λ = (2π/k), and the dynamical equations are the model H equations. The structure and rheology are determined by the relative magnitudes of the diffusion time for coarsening, (λ²/D) and the inverse of the strain rate ^-1, and the Ericksen number, which is the ratio of the shear stress and the layer stiffness. When the diffusion time is small compared with the inverse of the strain rate, there is a local formation of misaligned layers, which are deformed by the imposed flow. There is near-perfect ordering with isolated defects at low values of the Ericksen number, but the defects result in a significant increase in viscosity due to the high layer stiffness. At high values of the Ericksen number, the concentration field is deformed by the mean shear before layers form via diffusion. Cylindrical structures aligned along the flow direction form after about 8-10 strain units, and these evolve into layers with disorder through diffusion perpendicular to the flow. The layers are not perfectly ordered, even after hundreds of strain units, due to the creation and destruction of defects via shear. The excess viscosity is low because the layer stiffness is small compared with the applied shear at a high Ericksen number. This study provides guidance on how the material parameters and imposed flow can be tailored to achieve the desired rheological behaviour.

National Liver Allocation Policy-Consensus Document by the Liver Transplantation Society of India for a Nationally Uniform System of Allocation of Deceased Donor Liver Grafts

Background

Deceased donor liver transplantation (DDLT) is increasing in India and now constitutes nearly one-third of all liver transplantation procedures performed in the country. There is currently no uniform national system of allocation of deceased donor livers.

Methods

A national task force consisting of 19 clinicians involved in liver transplantation from across the country was constituted under the aegis of the Liver Transplantation Society of India to develop a consensus document addressing the above issues using a modified Delphi process of consensus development.

Results

The National Liver Allocation Policy consensus document includes 46 statements covering all aspects of DDLT, including minimum listing criteria, listing for acute liver failure, DDLT wait-list management, system of prioritisation based on clinical urgency for adults and children, guidelines for allocation of paediatric organs and allocation priorities for liver grafts recovered from public sector hospitals.

Conclusion

This document is the first step in the setting up of a nationally consistent policy of deceased donor liver allocation.

Single incision simultaneous liver kidney transplantation: Feasibility and outcomes

BACKGROUND

Traditionally, simultaneous liver kidney transplantation (SLK) has been performed using a subcostal incision for the liver allograft and a lower abdominal incision for kidney transplantation (dual incision, DI). At our institution, we performed SLK using a single subcostal incision (SI). The aim of this study was to report the outcomes of single versus dual incisions for SLK.

METHODS

A retrospective cohort study of consecutive SLK procedures performed at our center from January 2015 to April 2021 was performed. The demographic characteristics, complications, intraoperative findings, and complications after SI and DI were statistically compared.

RESULTS

A total 37 SLK were performed (19 DI and 18 SI). The age and indications for transplantation were comparable between the two groups. Patient in SI group had significantly higher MELD score (27.0 ± 1.5 vs. 31.7 ± 1.5, p = .038). The cold ischemic time of kidney transplantation (599 ± 26 min vs. 447 ± 27 min, p < .001) and the total surgical time (508 ± 21 min vs. 423 ± 22 min, p = .008) were significantly shorter in the SI group. The incidence of complications and post-transplant kidney function was comparable between the groups. A slightly higher incidence of surgical site complications was noted in the DI group without any statistically significance (p = .178).

CONCLUSIONS

Single-subcostal incision SLK is technically feasible and has comparable outcomes to dual-incision SLK. SI was associated with shorter cold ischemic time for kidney transplant, as well as shorter overall operative time.

A new approach for accurate determination of particle sizes in microfluidic impedance cytometry

In microfluidic impedance cytometry, the change in impedance is recorded as an individual cell passes through a channel between electrodes deposited on its walls, and the particle size is inferred from the amplitude of the impedance signal using calibration. However, because the current density is nonuniform between electrodes of finite width, there could be an error in the particle size measurement because of uncertainty about the location of the particle in the channel cross section. Here, a correlation is developed relating the particle size to the signal amplitude and the velocity of the particle through the channel. The latter is inferred from the time interval between the two extrema in the impedance curve as the particle passes through a channel with cross-sectional dimensions of 50 μm (width) × 30 μm (height) with two pairs of parallel facing electrodes. The change in impedance is predicted using 3D COMSOL finite-element simulations, and a theoretical correlation that is independent of particle size is formulated to correct the particle diameter for variations in the cross-sectional location. With this correlation, the standard deviation in the experimental data is reduced by a factor of two to close to the standard deviation reported in the manufacturer specifications.

Moving efficiently through a crowd: A nature-inspired traffic rule

In this article, we propose a traffic rule inspired from nature that instructs how a crowd made up of inert agents should respond to an elite agent to facilitate its motion through the crowd. When an object swims in a fluid medium or an intruder is forced through granular matter, characteristic flow fields are created around them. We show that if inert agents made small movements based on a traffic rule derived from these characteristic flow fields, then they efficiently reorganize and transport enough space for the elite to pass through. The traffic rule used in the article is a dipole field which satisfactorily captures the features of the flow fields around a moving intruder. We study the effectiveness of this dipole traffic rule using numerical simulations in a two-dimensional periodic domain, where one self-propelled elite agent tries to move through a crowd of inert agents that prefer to stay in a state of rest. Simulations are carried out for a wide range of strengths of the traffic rule and packing densities of the crowd. We characterize and analyze four regions in the parameter space-free-flow, motion due to cooperation and frozen and collective drift regions-and discuss the consequence of the traffic rule in light of the collective behavior observed. We believe that the proposed method can be of use in a swarm of robots working in constrained environments.

Combined Heart-Liver and Domino Liver Transplantation in Familial Amyloidosis

BACKGROUND

Combined heart-liver transplantation (CHLT) is the only curative option for patients with concomitant pathology affecting the heart and liver. In some cases, the native livers of familial amyloidosis (FA) patients may be suitable for domino transplantation into other recipients.

METHODS

Retrospective analysis (2013 to 2019) of all CHLT at our center was performed. Continuous data were presented as mean with standard deviation and discrete variables as percentages.

RESULTS

Familial amyloidosis was the indication for CHLT in 5 out of 6 patients. The mean recipient age was 55 ± 5.62 years. Two patients were bridged with total artificial heart. The mean model for end-stage liver disease score at transplant was 17.17 ± 3.7. Two explanted livers were used for transplantation in a domino fashion. The median intensive care and hospital stays were 5.5 and 19 days, respectively. Complications included renal failure (1), groin abscess (1), pulmonary embolism (1), and cardiac rejection (1). Patient and graft survival for both organs was 100% at a median follow-up of 59 (range 20-76) months.

DISCUSSION

Combined heart-liver transplantation for FA achieves excellent outcomes. The possible use of livers explanted from patients with FA for domino liver transplantation can contribute to the liver donor pool.

Utilization of a Reduced Graft from a Severely Traumatized Liver: A Case Report and Strategy to Increase Availability of Livers for Transplant

Background: Trauma victims with liver lacerations in the hilum are typically excluded from liver donation. We report a case of a successful liver transplant from a deceased donor with a grade 4 hilar liver laceration. Case Presentation: We used a liver with a high-grade laceration from a 28-year-old brain-dead traffic accident victim. The liver had grade IV lacerations in the right and caudate lobes. In situ split liver technique was applied to control the lacerations after an intraoperative cholangiogram revealed favourable anatomy. The left hemi-liver graft was procured, retaining the entire vena cava and the full length of the main hepatic vasculature. The recipient was a 62-year-old female patient with end-stage liver disease, with a Model for End-Stage Liver Disease-Sodium score of 19. The left lobe graft was transplanted using the standard piggy-back technique. The patient was discharged on postoperative day 7 after an uneventful recovery. At two-month follow-up, she continues to do well, with normal hepatic function and unremarkable imaging studies. Conclusion: This is the first reported case of a successful liver transplant of a severely lacerated liver made possible by the application of split liver techniques. In situ splitting of a severely traumatized liver could permit the utilization of a reduced graft for small recipients.

The "W" Technique: A Safe and Reproducible Technique for Hepatic Artery Reconstruction in Living Donor Liver Transplantation

Background

Reconstruction of the hepatic arterial inflow can be technically demanding in living donor liver transplantation, and thrombosis can result in graft loss and mortality. We describe the safe and reproducible “W” technique to reconstruct the hepatic artery and outcomes before and after adoption of the technique in a consecutive series of liver transplants at 2 high-volume living donor liver transplant centers.

Material/Methods

Prospectively collected data were analyzed to compare the outcomes before and after introduction of a standardized “W” technique for reconstruction of the hepatic artery in 2 high-volume living donor liver transplant programs.

Results

In a consecutive series of 675 liver transplants, of which 27 were deceased donor transplants and 648 were living donor transplants, 443 transplants were performed with a standard interrupted reconstruction of the hepatic artery under loupes. These transplants were performed by a single surgeon, with an incidence of hepatic artery thrombosis of 2%. After introduction of the “W” technique, despite the arterial reconstruction being done by several surgeons in the early part of their learning curve, the incidence of hepatic artery thrombosis decreased to 0.86% in the next 232 transplants.

Conclusions

The “W” technique is a simple, easy to learn and teach technique for reconstruction of the hepatic artery without the use of the operating microscope in living donor liver transplantation.

Management of hepatic artery aneurysm: A case series

Hepatic artery aneurysms are rare, but their diagnosis is important because of high mortality and complications. Common risk factors for developing these aneurysms include hypertension, vascular disease, pancreatitis, diabetes, tobacco use, autoimmune diseases, and previous transplantation. Frequent imaging for trauma and tumor surveillance has increased the incidence of naive hepatic aneurysms. These aneurysms can be difficult to manage, and it can be challenging to decide the correct treatment modality for the patient. Hereby, we present four cases of hepatic artery aneurysm and discuss various treatment options. Patient 1 suffered from a proper and right hepatic artery aneurysm discovered incidentally; repaired with an endovascular intervention later complicated by an endoleak which was further managed by another stenting. Patient 2 had a common hepatic artery aneurysm followed with serial imaging without any intervention. Patient 3 had a hepatic artery aneurysm and liver mass diagnosed concurrently. The patient underwent an open surgical repair of his aneurysm with graft and liver resection which was complicated later with rupture of aneurysm followed by surgical bypass repair. Patient 4 suffered from a large hepatic artery aneurysm causing bile duct compression. Her aneurysm was repaired open with splenic artery grafting. Patients were managed from careful observation to surgery with different outcomes.

A cartridge based Point-of-Care device for complete blood count

We demonstrate a proprietary lab-on-chip/μ TAS technology platform for a regulatory grade portable instrument for complete blood count (CBC) hematology tests including 3 part differential WBCs, RBCs, platelet and hemoglobin for rapid diagnostics at the point of care in resource-poor settings. Presently, diagnostics based on blood tests are confined to centralized laboratory settings, dependent on large footprint and expensive cytometers or on a microscope, requiring trained laboratory technicians. Consequently, such facilities are not present in rural and semi-urban settings, where there are opportunities and challenges in delivering efficient healthcare infrastructure at an affordable cost in resource-challenged environments. Our proposed design leverages advances in microfluidics and lab-on-chip fabrication techniques to miniaturize the conventional cytometer and bring down the cost significantly. The device can be operated autonomously, without skilled manpower, by primary healthcare professionals in the field and by patients (like glucose self-test devices). The instrument consists of a single-use chip, the size of a credit card, pre-loaded with reagents, in which the sample is loaded, and which is fluidically insulated from the environment. The controller, the size of a toaster, performs the necessary fluid handling and the impedance measurements to deliver the results in minutes.

An Overview of Liver Transplant Pathology: Data from a Tertiary Referral Centre in Western India

INTRODUCTION AND AIM

1. Study of liver explants - Etiologic types of end-stage chronic liver disease (ESCLD) and acute liver failure (ALF) in adults and children. 2. Assessment of donor steatosis and incidental granulomas. 3. Post-transplant liver biopsies.

MATERIAL AND METHODS

Specimens of 180 explant hepatectomies, 173 donor wedge and 30 core liver biopsies, and 58 post transplant liver biopsies received in our department from April 2013 to March 2017.

RESULTS

1. Most common causes of ESCLD in adults were: alcohol related (30.32%), hepatitis virus related (18.71%) and non-alcoholic steatohepatitis related (18.06%); and in children ≤ 12 years were: biliary atresia (27.27%), autoimmune disease (18.18%) and Wilson's disease (18.18%). Most common causes of ALF in adults and children were anti-tubercular therapy induced and idiopathic respectively. 2. Prevalence rate of moderate steatosis (between 30-60%) was 4.28%. Incidental granulomas were seen in 5 cases. 3. Most common diagnoses of post-transplant biopsies in adults included acute cellular rejection (ACR) (36.17%), recurrence of viral disease (8.51%) and moderate non-specific portal triaditis (8.51%). Among children ≤ 12 years, most common diagnoses included unremarkable liver parenchyma, ACR and ischemia/reperfusion injury.

CONCLUSION

1. Alcohol- and hepatitis- virus related ESCLD, and biliary atresia are leading indications for liver transplantation in adults and children respectively. 2. Prevalence of 4.28% of moderate steatosis, is much lower than that documented in western literature. Only 5 cases of incidental granulomas is unexpectedly low in a country endemic for tuberculosis. 3. Most common diagnoses of post-transplant liver biopsies in adults has been acute rejection, which is similar to the findings from much larger published series.

Effect of magnetic dipolar interactions and size dispersity on the origin of steady state magnetomechanical response in bidisperse Mn–Zn ferrite spherical particle based magnetorheological fluids

A mechanism for the excellent magneto-mechanical behaviour of bi-disperse spherical soft-ferrimagnetic Mn_0.7Zn_0.3Fe₂O₄ particle based magnetorheological fluids.

Magnetorheological fluids containing rod-shaped lithium-zinc ferrite particles: the steady-state shear response

We report the magnetic field and particle-concentration dependent steady-state shear-responses of rod shaped Li-Zn ferrite particle based magnetorheological fluids (MRFs). Rod-shaped soft ferrimagnetic Li-Zn ferrite (Li0.4Zn0.2Fe2.4O4) particles were synthesized using the combustion synthesis method. MRFs of three different particle-concentrations (φ = 0.1, 0.2 and 0.4, in weight fraction) were prepared using silicone oil. Their yield strength and dynamic viscosity were studied at different applied magnetic fields (B). With an increase in B and φ, the yield strength (τY) of the MRFs increases. This behaviour is assigned to the formation of stronger columnar structures of the magnetically interacting particles which resist the flow (shear) of the MRF. For the MRF with φ = 0.4 and B = 1.2 T, we observed a maximum τY value of ∼1.25 kPa. Furthermore, we observed that, based on the on-state to off-state viscosity ratio (ηon/ηoff) at a particular operating B value, the optimum particle concentration required for energy- and cost-efficient operation of the MRFs can be chosen. The absence of a stabilizing-agent or de-agglomerating-coating, the low density, and the excellent oxidation- and corrosion-resistance of the soft ferrimagnetic rod-shaped Li-Zn ferrite particles make this MRF-system highly versatile and economical for many magneto-mechanical applications.

Abernethy malformation: Single-center experience from India with review of literature

Abernethy malformation is a rare congenital anomaly in which there is direct communication between the portal and systemic venous circulation. The clinical presentation ranges from asymptomatic with incidental detection on imaging to secondary complications of disease or related to associate anomalies. This is a retrospective analysis of data from nine patients with Abernethy malformation at a single center. This is a referral center for Pediatric Cardiology and for Hepatobiliary and Pancreatic Surgery. The patients presented to the Pulmonary Hypertension Clinic/the Hepatobiliary Surgery Clinic. Out of nine patients, four were male. Type II Abernethy malformation was present in five patients whereas three patients had type I malformation. One of the patients had communication between inferior mesenteric vein and internal iliac vein. Five out of nine patients were erroneously diagnosed as idiopathic primary pulmonary hypertension and were treated with vasodilators. One patient required living donor liver transplant. One patient was managed with surgical shunt closure whereas two patients required transcatheter shunt closure. The rest of the patients were managed conservatively. Abernethy malformation is more common than previously thought and the diagnosis is often missed. There are various management options for Abernethy malformation, which includes surgical or transcatheter shunt closure and liver transplant. Management of Abernethy malformation depends upon type, presentation, and size of shunt.

Kinetics of liver regeneration in donors after living donor liver transplantation: A retrospective analysis of "2/3rd partial hepatectomy" model at 3 months

BACKGROUND/AIM

Right lobe living donor (2/3rd partial hepatectomy) model is the best way to accurately study liver regeneration process in human beings. We aimed to study the kinetics of liver regeneration after 2/3rd partial hepatectomy in donors.

METHODS

Retrospective analysis of prospectively maintained volumetric recovery data in donors was performed in 23 donors, who underwent 29 contrast-enhanced computed tomography within 3 months for various clinical indications.

RESULTS

The absolute volumetric growth percentages were as follows: 37.60 ± 21.74 at 1st week, 92 ± 53.27 at 2nd week, 115.55 ± 59.65 at 4th week, and 110.79 ± 64.47 at 3 months. On sub-group analysis of our cohort, we found that 4.3%, 17%, 30.4%, and 39% donors attended ≥ 90% volumetric recovery at 1st, 2nd, 4th week, and 3 months, respectively. One patient at 4th week revealed 128% volumetric recovery. There was one more patient who exceeded original total liver volumes (TLV) (111% of TLV) at 2.5 months. The serum bilirubin and INR values peaked at postoperative day (POD) 3rd and then started showing a downward trend from POD 5th onwards.

CONCLUSION

Our study is the first to document complete volumetric recovery in donors as early as 3 weeks. Two of the donors overshot their original TLV during the early regenerative phase.

Effect of particle stiffness on contact dynamics and rheology in a dense granular flow

Dense granular flows have been well described by the Bagnold rheology, even when the particles are in the multibody contact regime and the coordination number is greater than 1. This is surprising, because the Bagnold law should be applicable only in the instantaneous collision regime, where the time between collisions is much larger than the period of a collision. Here, the effect of particle stiffness on rheology is examined. It is found that there is a rheological threshold between a particle stiffness of 10^{4}-10^{5} for the linear contact model and 10^{5}-10^{6} for the Hertzian contact model above which Bagnold rheology (stress proportional to square of the strain rate) is valid and below which there is a power-law rheology, where all components of the stress and the granular temperature are proportional to a power of the strain rate that is less then 2. The system is in the multibody contact regime at the rheological threshold. However, the contact energy per particle is less than the kinetic energy per particle above the rheological threshold, and it becomes larger than the kinetic energy per particle below the rheological threshold. The distribution functions for the interparticle forces and contact energies are also analyzed. The distribution functions are invariant with height, but they do depend on the contact model. The contact energy distribution functions are well fitted by Gamma distributions. There is a transition in the shape of the distribution function as the particle stiffness is decreased from 10^{7} to 10^{6} for the linear model and 10^{8} to 10^{7} for the Hertzian model, when the contact number exceeds 1. Thus, the transition in the distribution function correlates to the contact regime threshold from the binary to multibody contact regime, and is clearly different from the rheological threshold. An order-disorder transition has recently been reported in dense granular flows. The Bagnold rheology applies for both the ordered and disordered states, even though the rheological constants differ by orders of magnitude. The effect of particle stiffness on the order-disorder transition is examined here. It is found that when the particle stiffness is above the rheological threshold, there is an order-disorder transition as the base roughness is increased. The order-disorder transition disappears after the crossover to the soft-particle regime when the particle stiffness is decreased below the rheological threshold, indicating that the transition is a hard-particle phenomenon.

Magnetic field dependent steady-state shear response of Fe3O4 micro-octahedron based magnetorheological fluids

The magneto-rheological behaviour of fluids containing soft-ferrimagnetic Fe₃O₄ micro-octahedrons (M = magnetization, τ_Y = dynamic yield-stress and H = applied-magnetic-field).

On The Origin of Shear Stress Induced Myogenesis Using PMMA Based Lab-on-Chip

One of the central themes in cell and tissue engineering is to develop an understanding as to how biophysical cues can influence cell functionality changes. The flow induced shear stress is regarded as one such biophysical cue to influence physiological changes in shear-sensitive tissues, in vivo. The origin of such phenomena is, however, poorly understood. While addressing such an issue, the present work demonstrates the intriguing synergistic effect of shear stress and spatial constraints in inducing aligned growth and differentiation of myoblast cells to myotubes. In a planned set of in vitro experiments, the regulation of laminar flow regime within a narrow window was obtained in a PMMA-based Lab-on-Chip (LOC) device, wherein the murine muscle cells (C2C12), chosen for their phenotypical differentiation stages, were cultured under graded shear conditions. The two factors of shear stress and spatial allowance were decoupled by another two sets of experiments. This aspect has been conclusively established using a PMMA device having a fixed width microchannel with varying shear and an identical amount of shear with different width of channels. On the basis of the extensive analysis of biochemical assays (WST-1, picogreen) together with gene expression using qRT-PCR and cell morphological changes (fluorescence/confocal microscopy), extensive differentiation of the myoblasts into myotubes is found to be dependent on both shear stress and spatial allocation with a maximum at an optimal shear of ca. 16 mPa. Quantitatively, the mRNA expression of myogenic biomarkers, i.e., myogenin, MyoD, and neogenin, exhibited 10- to 50-fold changes at ca. 16 mPa shear flow, compared to that under static conditions. Also, myotube aspect ratio and myotube density are modulated with shear stress and are in commensurate with gene expression changes. The flow cytometry analysis further confirmed that the cell cycle arrest at the G1/G0 phase triggers the onset of myogenesis. Taken together, the present study unambiguously establishes qualitative and quantitative biophysical basis for the origin of myogenesis toward the critical shear stress of murine myoblasts in a microfludic device, in vitro.

Simultaneous living donor liver transplant with sleeve gastrectomy for metabolic syndrome and NASH-related ESLD-First report from India

Nonalcoholic steatohepatitis (NASH) with morbid obesity and metabolic syndrome is now a common cause of end-stage liver disease (ESLD). These patients are high-risk candidates for liver transplant, and require bariatric surgery to prevent recurrent disease in the new liver. Data reports bariatric surgery after transplant, which maybe difficult because of adhesions between the stomach and liver in living donor liver transplant (LDLT) recipient. We report the first case of combined LDLT with sleeve gastrectomy (SG) from India. A morbidly obese diabetic woman with NASH-related ESLD was planned for combined right lobe LDLT with open SG, in view of failed diet therapy, musculo-skeletal complaints, and restricted mobility. Postoperatively, with liver graft functioning adequately, bariatric diet restrictions resulted in maximum reduction of 25% weight, achieving a target BMI below 30 kg/m² within 2 months, along with complete cure of diabetes and better ambulation. Thus, combination of LDLT and bariatric surgery in the same sitting is safe and effective in management of metabolic syndrome and associated NASH-related ESLD.

System size dependence of the structure and rheology in a sheared lamellar liquid crystalline medium

The structural and rheological evolution of an initially disordered lamellar phase system under a shear flow is examined using a mesoscale model based on a free energy functional for the concentration field, which is the scaled difference in the concentration between the hydrophilic and hydrophobic components. The dimensionless numbers which affect the shear evolution are the Reynolds number (γ˙¯L²/ν), the Schmidt number (ν/D), a dimensionless parameter Σ=(Aλ²/ρν²), a parameter μ_r which represents the viscosity contrast between the hydrophilic and hydrophobic components, and (L/λ), the ratio of system size and layer spacing. Here, ρ, ν, and D are the density, kinematic viscosity (ratio of viscosity and density), and the mass diffusivity, and A is the energy density in the free energy functional which is proportional to the compression modulus. Two distinct modes of structural evolution are observed for moderate values of the parameter Σ depending only on the combination ScΣ and independent of system size. For ScΣ less than about 10, the layers tend to form before they are deformed by the mean shear, and layered but misaligned domains are initially formed, and these are deformed and rotated by the flow. In this case, the excess viscosity (difference between the viscosity and that for an aligned state) does not decrease to zero even after 1000 strain units, but appears to plateau to a steady state value. For ScΣ greater than about 10, layers are deformed by the mean shear before they are fully formed, and a well aligned lamellar phase with edge dislocation orders completely due to the cancellation of dislocations. The excess viscosity scales as t^-1 in the long time limit. The maximum macroscopic viscosity (ratio of total stress and average strain rate over the entire sample) during the alignment process increases with the system size proportional to (L/λ)^3/2. For large values of Σ, there is localisation of shear at the walls, and the bulk of the sample moves as a block. The thickness of the shearing region appears to be invariant with the system size, leading to an increase of viscosity proportional to L. The time for structural evolution is found to be the inverse of the strain rate γ˙^-1. In the case of a significant viscosity contrast between the hydrophilic and hydrophobic parts, the average viscosity increases by 1-2 orders of magnitude due to the defect pinning mechanism, where the regions between defects move as a block, and shear localisation at the wall.

Fabrication of electrodes with ultralow platinum loading by RF plasma processing of self-assembled arrays of Au@Pt nanoparticles

Conductive, carbon-free, electrocatalytically active, nanostructured electrodes with ultra-low platinum loading were fabricated using self-assembly of octadecanethiol-coated Au@Pt nanoparticles followed by RF plasma treatment. Bilayer arrays of Au@Pt nanoparticles with platinum loadings of 0.50, 1.04, 1.44, and 1.75 μg cm(-2) (corresponding to 0.5, 1, 1.5 and 2 atomic layer coverage of platinum on nominally 5 nm gold core) were subjected to RF argon plasma treatment for various durations and their electrical conductivity, morphological evolution, and electrocatalytic activity characterized. Samples with monolayer and above platinum coverages exhibit maximum electrochemically active surface areas values of ∼100 m(2)/gpt and specific activities that are ∼4× to 6× of a reference platinum nanoparticle bilayer array. The underlying gold core influences the structural evolution of the samples upon RF plasma treatment and leads to the formation of highly active Pt(110) facets on the surface at an optimal plasma treatment duration, which also corresponds to the onset of a sharp decline in lateral sheet resistance. The sample having a two atom thick platinum coating has the highest total mass activity of 48 ± 3 m(2)/g(pt+au), corresponding to 44% Pt atom utilization, while also exhibiting enhanced CO tolerance as well as high methanol oxidation reaction and oxygen reduction reaction activity.

Structure-rheology relationship in a sheared lamellar fluid

The structure-rheology relationship in the shear alignment of a lamellar fluid is studied using a mesoscale model which provides access to the lamellar configurations and the rheology. Based on the equations and free energy functional, the complete set of dimensionless groups that characterize the system are the Reynolds number (ργL(2)/μ), the Schmidt number (μ/ρD), the Ericksen number (μγ/B), the interface sharpness parameter r, the ratio of the viscosities of the hydrophilic and hydrophobic parts μ(r), and the ratio of the system size and layer spacing (L/λ). Here, ρ and μ are the fluid density and average viscosity, γ is the applied strain rate, D is the coefficient of diffusion, B is the compression modulus, μ(r) is the maximum difference in the viscosity of the hydrophilic and hydrophobic parts divided by the average viscosity, and L is the system size in the cross-stream direction. The lattice Boltzmann method is used to solve the concentration and momentum equations for a two dimensional system of moderate size (L/λ=32) and for a low Reynolds number, and the other parameters are systematically varied to examine the qualitative features of the structure and viscosity evolution in different regimes. At low Schmidt numbers where mass diffusion is faster than momentum diffusion, there is fast local formation of randomly aligned domains with "grain boundaries," which are rotated by the shear flow to align along the extensional axis as time increases. This configuration offers a high resistance to flow, and the layers do not align in the flow direction even after 1000 strain units, resulting in a viscosity higher than that for an aligned lamellar phase. At high Schmidt numbers where momentum diffusion is fast, the shear flow disrupts layers before they are fully formed by diffusion, and alignment takes place by the breakage and reformation of layers by shear, resulting in defects (edge dislocations) embedded in a background of nearly aligned layers. At high Ericksen number where the viscous forces are large compared to the restoring forces due to layer compression and bending, shear tends to homogenize the concentration field, and the viscosity decreases significantly. At very high Ericksen number, shear even disrupts the layering of the lamellar phase. At low Ericksen number, shear results in the formation of well aligned layers with edge dislocations. However, these edge dislocations take a long time to anneal; the relatively small misalignment due to the defects results in a large increase in viscosity due to high layer stiffness and due to shear localization, because the layers between defects get pinned and move as a plug with no shear. An increase in the viscosity contrast between the hydrophilic and hydrophobic parts does not alter the structural characteristics during alignment. However, there is a significant increase in the viscosity, due to pinning of the layers between defects, which results in a plug flow between defects and a localization of the shear to a part of the domain.

Endoscopic management of post-liver transplant billiary complications: A prospective study from tertiary centre in India

BACKGROUND

Liver transplantation has become common in India over the last decade and biliary strictures after the procedure cause a significant morbidity. Endoscopic retrograde cholangiopancreatography (ERCP) is a safe and effective treatment modality for post-transplant biliary strictures so we decided to evaluate prospectively the outcomes of endoscopic treatment in post-living donor liver transplantation (LDLT) biliary strictures.

METHODS

We studied ten consecutive patients who had developed biliary strictures (out of 312 who had undergone liver transplantation between June 2009 and June 2013) and had been referred to the Department of Gastroenterology for management. All patients underwent liver function tests, ultrasound of the abdomen, magnetic resonance cholangiography and liver biopsy, if this was indicated.

RESULTS

Of these 312 patients who underwent liver transplantation, 305 had living donors (LDLT) and 7 deceased donors (DDLT). Ten patients in the LDLT group (3.3%) developed biliary strictures. There were seven males and three females who had median age of 52 years (range 4-60 years). The biliary anastomosis was duct-to-duct in all patients with one patient having an additional duct-to-jejunum anastomosis. The mode of presentation was cholangitis in four patients (40%), asymptomatic elevation of liver enzymes in four (40%) and jaundice in two patients (20%). The median time from transplantation to the detection of the stricture was 12 months (2-42.5 months). ERCP was attempted as initial therapy in all patients: seven were managed entirely by endoscopic therapy, and three required a combined percutaneous and endoscopic approach. Cholangiography demonstrated anastomotic stricture in all patients. A total of 32 sessions of ERCP were done with mean of 3.2 (2-5) endoscopic sessions and 3.4 (1-6) stents required to resolve the stricture. The median time from the first intervention to stricture resolution was 4 months (range 2-12 months). In four patients, the stents were removed after one session and in two patients each after two, three and four sessions. In six patients more than one stent was placed and all of them required dilatation of stricture. Seven patients completed treatment and are off stents at a median follow up period of 9.5 months (7-11 months). Two patients developed recurrence of their stricture after 7.5 months. Both had long strictures and required a combined endoscopic and percutaneous approach. There was one mortality due to sepsis secondary to cholangitis.

CONCLUSIONS

Post-LDLT biliary strictures can be successfully treated with ERCP, and most patients remain well on follow up (median 9.5 months). A combined endoscopic and percutaneous approach is useful when ERCP alone fails.

Complex Rectovaginal Fistula-an Experience at a Tertiary Care Centre

Complex rectovaginal fistulae are difficult to manage. With an initial failed attempt, a simple fistula becomes complex and the success rate of a subsequent repair decreases. A review of our prospectively maintained records over a period of 16 years revealed 25 patients with rectovaginal fistulae. A variety of procedures was performed in these patients according to their aetiology, site and if there had been a previous attempt at repair. The mean age of the patients was 45 years. The most common cause was operative trauma in 14 cases. Ten patients had previous attempts at repair which had not been successful. The surgical procedures we performed included re-enforcement flaps, resection with diversion, repair with re-enforcement with omentum and simple diversion. Two patients developed recurrence, and one of them healed after a second repair. No recurrence developed in 10 patients who had failed attempts at repair elsewhere. Our experience has shown that most complex rectovaginal fistulae can be successfully repaired but they might require repeated operations. Faecal diversion is usually necessary, and in recurrent fistulae, we found that rather than a local repair, a muscle flap or omental interposition improves the chances of healing.

Digital model as an alternative to plaster model in assessment of space analysis

Introduction:

Digital three-dimensional models are widely used for orthodontic diagnosis. The purpose of this study was to appraise the accuracy of digital models obtained from computer-aided design/computer-aided manufacturing (CAD/CAM) and cone-beam computed tomography (CBCT) for tooth-width measurements and the Bolton analysis.

Materials and Methods:

Digital models (CAD/CAM, CBCT) and plaster model were made for each of 50 subjects. Tooth-width measurements on the digital models (CAD/CAM, CBCT) were compared with those on the corresponding plaster models. The anterior and overall Bolton ratios were calculated for each participant and for each method. The paired t-test was applied to determine the validity.

Results:

Tooth-width measurements, anterior, and overall Bolton ratio of digital models of CAD/CAM and CBCT did not differ significantly from those on the plaster models.

Conclusion:

Hence, both CBCT and CAD/CAM are trustable and promising technique that can replace plaster models due to its overwhelming advantages.

Implementation of a surgical safety checklist and postoperative outcomes: a prospective randomized controlled study

The implementation of a surgical safety checklist is said to minimize postoperative surgical complications. However, to our knowledge, no randomized controlled study has been done on the influence of checklists on postoperative outcomes in a developing country. We conducted a prospective randomized controlled study with parallel group study design of the implementation of WHO surgical safety checklist involving 700 consecutive patients undergoing operations in our hospital between February 2012 and April 2013. In 350 patients, the checklist was implemented with modifications-the Rc arm. The control group of 350 patients was termed the Rn arm. The checklist was filled in by a surgery resident, and only the participants in the study were blinded. Postoperative wound-related (p = 0.04), abdominal (p = 0.01), and bleeding (p = 0.03) complications were significantly lower in the Rc compared to the Rn group. The number of overall and higher-grade complications (Clavien-Dindo grades 3 and 4) per patient reduced from 0.97 and 0.33 in the Rn arm to 0.80 and 0.23 in the Rc arm, respectively. A significant reduction in mortality was noted in the Rc arm as compared to the Rn arm (p = 0.04). In a subgroup analysis, the number of overall and higher-grade complications per patient with incomplete checklists was higher than that with fully completed checklist group. Implementation of WHO surgical safety checklist results in a reduction in mortality as well as improved postoperative outcomes in a tertiary care hospital in a developing country.