Pancreatic neuroendocrine tumour resection in circumportal pancreas: a rare anatomical anomaly with important surgical implications.

Various congenital anomalies of the pancreas have been reported due to its complex embryological development involving the fusion of two separate buds. Circumportal pancreas is a rare anatomical anomaly where the pancreatic head and uncinate process fuse abnormally with the pancreatic body, encasing the portal vein and/or superior mesenteric vein completely. This anomaly poses several challenges to hepatobiliary surgeons, as the encasement of the portal vein by the abnormal pancreatic tissue makes an additional parenchymal transection necessary. Vascular variants have also been reported with circumportal pancreas, which, if not recognised preoperatively, can be catastrophic. Therefore, careful preoperative evaluation and planning are essential, to ensure safe pancreatic resection and recovery in a patient with circumportal pancreas. We present a case of a successful subtotal pancreatectomy and splenectomy in a patient with circumportal pancreas, for a suspected pancreatic duct adenocarcinoma. The aim of this case report is to contribute valuable insights that can aid hepatobiliary surgeons in enhancing their preoperative planning when encountered with patients with similar anatomical variances.

Quantifying Perioperative Risks for Antireflux and Hiatus Hernia Surgery: A Multicenter Cohort Study of 4301 Patients.

OBJECTIVE: Using a comprehensive Australian cohort, we quantified the incidence and determined the independent predictors of intraoperative and postoperative complications associated with antireflux and hiatus hernia surgeries. In addition, we performed an in-depth analysis to understand the complication profiles associated with each independent risk factor. BACKGROUND: Predicting perioperative risks for fundoplication and hiatus hernia repair will inform treatment decision-making, hospital resource allocation, and benchmarking. However, available risk calculators do not account for hernia anatomy or technical aspects of surgery in estimating perioperative risk. METHODS: Retrospective analysis of all elective antireflux and hiatus hernia surgeries in 36 Australian hospitals over 10 years. Hierarchical multivariate logistic regression analyses were performed to determine the independent predictors of intraoperative and postoperative complications accounting for patient, surgical, anatomic, and perioperative factors. RESULTS: A total of 4301 surgeries were analyzed. Of these, 1569 (36.5%) were large/giant hernias and 292 (6.8%) were revisional procedures. The incidence rates of intraoperative and postoperative complications were 12.6% and 13.3%, respectively. The Charlson Comorbidity Index, hernia size, revisional surgery, and baseline anticoagulant usage independently predicted both intraoperative and postoperative complications. These risk factors were associated with their own complication profiles. Finally, using risk matrices, we visualized the cumulative impact of these 4 risk factors on the development of intraoperative, overall postoperative, and major postoperative complications. CONCLUSIONS: This study has improved our understanding of perioperative morbidity associated with antireflux and hiatus hernia surgery. Our findings group patients along a spectrum of perioperative risks that inform care at an individual and institutional level.

Graft-derived cfDNA Monitoring in Plasma and Bile During Normothermic Machine Perfusion in Liver Transplantation Is Feasible and a Potential Tool for Assessing Graft Viability.

BACKGROUND: Ex vivo normothermic machine perfusion (NMP) is an organ preservation technique that enables an extended assessment of graft suitability before liver transplantation (LT). Established monitoring protocols used during NMP vary significantly in their assessment of transplant suitability when applied to the same grafts. Graft-derived cell-free DNA (gdcfDNA) analysis is an emerging tool for monitoring graft health post-transplantation. We investigated the feasibility of monitoring gdcfDNA during NMP for LT in a proof-of-concept, observational study. METHODS: Serial plasma and bile samples were collected during NMP for 10 consecutive grafts, at 15 min post-machine reperfusion and then 2-h intervals. Digital polymerase chain reaction was used to quantify gdcfDNA at each time point. RESULTS: Five grafts were suitable for LT, there were no cases of primary nonfunction or death in the recipients. gdcfDNA was quantified in all bile and plasma samples (n > 100). In plasma, gdcfDNA concentrations climbed post-machine reperfusion until 4.25 h (median 2.25 h = 15.98 × 10 6 copies/mL, 4.25 h = 40.21 × 10 6 copies/mL). gdcfDNA levels then diverged significantly when comparing the viable and non-viable graft groups (6.25 h, median viable: 117.15 × 10 6 copies/mL versus non-viable: 16.72 × 10 6 copies/mL, P = 0.01). These opposing trends correlated in each graft and in all cases with the viable/non-viable outcome. There was a trend of gradual decline in bile gdcfDNA from viable grafts post-machine reperfusion; discarded grafts showed more variable patterns of release. CONCLUSIONS: gdcfDNA analysis during NMP is a feasible and potential tool to inform viability assessment during NMP for LT. Bile gdcfDNA monitoring offers the prospect of an objective means to assess the degree of biliary injury associated with organ procurement.

Migrated Laparoscopic Surgical Clips Causing Acute Cholangitis 32 Years After Laparoscopic Cholecystectomy.

Surgical clip migration post-laparoscopic cholecystectomy is a rare but important complication to consider in patients presenting with biliary obstruction. Titanium surgical clips are widely used in laparoscopic surgery to ligate vessels and ducts and are particularly important in laparoscopic cholecystectomy to ligate the cystic duct. More common complications associated with clips involve dislodgement, however, there are reported cases of migration into visceral structures causing an obstruction. We describe a case that demonstrated an acute migration of surgical clips into the common bile duct (CBD) within a three-week period, which occurred 32 years after laparoscopic cholecystectomy, likely attributed to erosion. On the patient's first presentation, she had acute pancreatitis with a CT demonstrating clips in the correct position. Three weeks later, the patient presented a second time with acute cholangitis and the repeat CT demonstrated the clips in the CBD. We hypothesize that the erosion of the bile duct is due to the pressure effects from either intra-abdominal organ movements or subtle clip movements, and eventually, persistent erosion leading to intra-ductal migration of the clips with the passage of the clips along the path of least resistance into the CBD, resulting in biliary obstruction. Management included standard treatment for biliary obstruction with intravenous broad-spectrum antibiotics and endoscopic retrograde cholangiopancreatography with excellent outcomes.

Graft-Derived Cell-Free DNA Quantification following Liver Transplantation Using Tissue-Specific DNA Methylation and Donor-Specific Genotyping Techniques: An Orthogonal Comparison Study.

Background: Graft-derived cell-free DNA (gdcfDNA) analysis has shown promise as a non-invasive tool for monitoring organ health following solid organ transplantation. A number of gdcfDNA analysis techniques have been described; however, the majority rely on sequencing or prior genotyping to detect donor-recipient mis-matched genetic polymorphisms. Differentially methylated regions of DNA can be used to identify the tissue-of-origin of cell-free DNA (cfDNA) fragments. In this study, we aimed to directly compare the performance of gdcfDNA monitoring using graft-specific DNA methylation analysis and donor-recipient genotyping techniques in a pilot cohort of clinical samples from patients post-liver transplantation. Results: 7 patients were recruited prior to LT, 3 developed early, biopsy-proven TCMR in the first 6 weeks post-LT. gdcfDNA was successfully quantified in all samples using both approaches. There was a high level of technical correlation between results using the two techniques (Spearman testing, rs = 0.87, p < 0.0001). gdcfDNA levels quantified using the genotyping approach were significantly greater across all timepoints in comparison to the tissue-specific DNA methylation-based approach: e.g., day 1 post-LT median 31,350 copies/mL (IQR 6731-64,058) vs. 4133 copies/mL (IQR 1100-8422), respectively. Qualitative trends in gdcfDNA levels for each patient were concordant between the two assays. Acute TCMR was preceded by significant elevations in gdcfDNA as quantified by both techniques. Elevations in gdcfDNA, using both techniques, were suggestive of TCMR in this pilot study with a 6- and 3-day lead-time prior to histological diagnosis in patients 1 and 2. Conclusions: Both the graft-specific methylation and genotyping techniques successfully quantified gdcfDNA in patients post-LT with statistically significant concordance. A direct comparison of these two techniques is not only important from a technical perspective for orthogonal validation, but significantly adds weight to the evidence that gdcfDNA monitoring reflects the underlying biology. Both techniques identified LT recipients who developed acute TCMR, with several days lead-time in comparison to conventional diagnostic workflows. Whilst the two assays performed comparably, gdcfDNA monitoring based on graft-specific DNA methylation patterns in cfDNA offers major practical advantages over the donor-recipient genotyping, and hence enhances the potential to translate this emerging technology into clinical practice.

Pre-existing hiatal mesh increases morbidity during and after revisional antireflux surgery: A retrospective multicenter study.

BACKGROUND: Revisional antireflux surgery, including hiatus hernia repair, is increasingly common. Mesh-augmented hiatal closure at the time of index operation is controversial but commonly performed. Although a meta-analysis of randomized data has demonstrated no additional benefit of routine mesh placement, it is unclear whether this practice results in harm, particularly at the time of revisional antireflux surgery. We determined whether pre-existing mesh at the hiatus increases morbidity during and after revisional antireflux surgery. METHODS: Analysis of prospectively-maintained databases of all elective revisional antireflux surgery cases in 36 hospitals across Australia took place over 10 years. Intraoperative and postoperative outcomes of patients with and without prior hiatal mesh were compared. Propensity score-matched analysis was used to validate primary findings. RESULTS: A total of 346 revisional cases (35 with pre-existing mesh) were analyzed. The 2 groups had comparable baseline characteristics. In total, 77 (22.2%) patients had 148 intraoperative adverse events. Pre-existing mesh was associated with a higher risk of intraoperative complications (48.6% vs 22.5%, odds ratio 3.25, 95% confidence interval 1.63-6.38, P = .002), secondary to bleeding, and lacerations to pleura, lung, and liver. Overall, 63 (18.2%) patients developed postoperative complications. Pre-existing mesh was associated with increased postoperative morbidity (37.1% vs 16.1%, odds ratio 3.09, 95% confidence interval 1.50-6.43, P = .005), particularly due to bleeding and respiratory complications. Importantly, pre-existing mesh independently predicted the occurrence of intraoperative and postoperative complications. CONCLUSION: Prior hiatal mesh significantly increases morbidity during and after revisional antireflux surgery. Given that revisional surgery is increasingly being performed, our findings discourage routine mesh use during primary antireflux surgery.

Optimal Timing of Perioperative Chemoprophylaxis in Patients With High Thromboembolic Risk Undergoing Major Abdominal Surgery: A Multicenter Cohort Study.

OBJECTIVE: To determine whether early (before skin closure) versus postoperative chemoprophylaxis affects the incidence of venous thromboembolism (VTE) and bleeding following major abdominal surgery, in a high thromboembolic risk population. BACKGROUND: Major abdominal surgery incurs both VTE and bleeding risks. Patients with high preoperative VTE risk derive the most benefit from chemoprophylaxis, but carry an increased risk of bleeding. The optimal window for chemoprophylaxis in the perioperative period, whereby both VTE and bleeding risks are minimized, is unknown. METHODS: Analysis of pooled data from 5 multicenter studies including only high thromboembolic risk (Caprini score >4) patients. Clinical VTE was defined as radiographically proven symptomatic disease <30 days postsurgery. Major bleeding was defined as the need for blood transfusion, reintervention, or >20 g/L fall in hemoglobin. RESULTS: From 5501 cases, chemoprophylaxis was initiated early in 1752 (31.8%) patients and postoperatively in 3749 (68.2%) patients. Baseline characteristics were similar between study groups. The incidence of clinical VTE was not associated with chemoprophylaxis timing [early 0.7% vs. postop 0.7%, odds ratio (OR): 1.11, 95% confidence interval (CI): 0.60-2.15, P =0.730]. Contrastingly, compared with postoperative chemoprophylaxis, early usage increased the risk of all bleeding (5.1% vs. 2.6%, OR: 2.04, 95% CI: 1.52-2.73, P <0.001) major bleeding (3.6% vs. 1.8%, OR: 1.99, 95% CI: 1.40-2.81, P <0.001), and reintervention (2.0% vs. 1.0%, OR: 2.10, 95% CI: 1.32-3.35, P =0.003). Early chemoprophylaxis independently predicted postoperative bleeding (OR: 1.71, 95% CI: 1.25-2.34, P <0.001), but not VTE. CONCLUSIONS: In high VTE risk patients undergoing major abdominal surgery, chemoprophylaxis commenced postoperatively reduces bleeding risk without affecting clinical VTE risk.

Laparoscopic choledochoscopy for choledocholithiasis is possible in the anatomical anomaly of left gallbladder.

Laparoscopic cholecystectomy (LC) is more challenging in the anatomical variation of left-sided gallbladder with the anomaly also highly related to biliary anomalies. Therefore, there has been a reluctance to operate close to the common bile duct (CBD) in left gallbladder patients, and thus choledocholithiasis is usually treated with endoscopic retrograde cholangiopancreatography (ERCP). There is emerging evidence that single stage LC and CBD exploration for choledocholithiasis may be superior to two stage LC and ERCP in terms of short-term and long-term morbidity, cost and length of stay. With the re-emergence of laparoscopic choledochoscopy, the purpose of this case report is to demonstrate the feasibility of this approach for choledocholithiasis.

Evaluating DNA recovery efficiency following bisulphite modification from plasma samples submitted for cell-free DNA methylation analysis.

The detection of methylated templates in cell-free DNA (cfDNA) is increasingly recognized as a valuable, non-invasive tool for diagnosis, monitoring and prognostication in a range of medical contexts. The importance of controlling pre-analytical conditions in laboratory workflows prior to cfDNA quantification is well-established. Significant variations in the recovery of DNA following processes such as cfDNA extraction and sodium bisulphite modification may confound downstream analysis, particularly when accurate quantification of templates is required. Given the wealth of potential applications for this emerging molecular technology, attention has turned to the requirement to recognize and minimize pre-analytical variables prior to cfDNA methylation analysis. We recently described the development of an approach using an exogenous DNA construct to evaluate the recovery efficiency of cfDNA following the extraction and bisulphite modification steps (CEREBIS). Here, we report our experience in the practical application of this technique in 107 consecutive patient plasma samples submitted for quantitative cfDNA methylation analysis. The mean recovery of cfDNA (as estimated using cerebis), following extraction and bisulphite modification, was 37% ± 7%. Nine (8.4%) of the 107 samples were found to be outside of control limits, where the recovery of cerebis indicated significant differences in the efficiency of the pre-analytical processing of these samples. Recognition of these out-of-control samples precluded subsequent molecular analysis. Implementation of data-driven quality control measures, such as the one described, has the potential to improve the quality of liquid biopsy methylation analysis, interpretation and reporting.

Malnutrition and low muscle strength are independent predictors of clinical outcomes and healthcare costs after liver transplant.

BACKGROUND & AIMS: Malnutrition and sarcopenia are associated with increased morbidity and mortality in cirrhosis but conflicting data are reported after liver transplantation (LT), with little known about the economic burden of malnutrition at LT. This study aims to investigate the impact of pre-transplant malnutrition and muscle strength on post-transplant clinical outcomes and healthcare costs. METHODS: Pre-transplant nutritional status (via subjective global assessment, SGA) and handgrip strength (HGS) were assessed in patients transplanted from 2009-2017. Descriptive statistics and regression analysis were used to analyse the association between nutrition and muscle function with post-LT clinical outcomes and hospital costs. RESULTS: 373 patients (70% male, median age 55 [IQR: 47, 60]) were transplanted, with 79% malnourished and mean HGS 31.4 ± 9.35 kg for males and 17.6 ± 5.78 kg for females. Malnutrition and reduced HGS independently predicted adverse post-transplant outcomes. ICU length of stay (LOS) was associated with severe malnutrition (HR (time to discharge (TTD)) 0.706, p = 0.014) and low HGS (HR (TTD) 0.692, p = 0.003); hospital LOS with severe malnutrition (HR (TTD) 0.759, p = 0.049) and low HGS (HR (TTD) 0.730, p = 0.011), and post-transplant infection with severe malnutrition (OR 1.76, p = 0.042) and low HGS (OR 1.83, p = 0.015). Accordingly, hospital costs were 30% higher in severely malnourished compared to well-nourished recipients (p = 0.012). Neither malnutrition or impaired HGS were associated with post-transplant mortality. CONCLUSIONS: This large cohort study demonstrates malnutrition and muscle weakness are independently associated with early post-transplant morbidity, namely infection and ICU and hospital LOS; with significantly increased hospital costs. Strategies to combat malnutrition and deconditioning pre-transplant may improve patient and health system outcomes after LT.

Low Levels of Hepatocyte-Specific Methylation in Cell-Free DNA Are a Strong Negative Predictor for Acute T Cell-Mediated Rejection Requiring Treatment Following Liver Transplantation.

Graft-derived cell-free DNA (gdcfDNA) quantification is a promising, minimally invasive tool for detecting acute T cell-mediated rejection (ATCMR) following liver transplantation (LT). We investigated the utility of measuring hepatocyte-specific methylation in cfDNA (HS-cfDNA) to quantify gdcfDNA, examining its accuracy in detecting ATCMR in a prospective, cross-sectional study. Blood was collected from LT recipients immediately prior to graft biopsy for suspected rejection. HS-cfDNA was quantified using droplet-digital polymerase chain reaction. Prebiopsy liver function tests (LFTs) and HS-cfDNA levels were correlated with biopsy results and the primary outcome of treated biopsy-proven acute rejection (tBPAR). A total of 51 patients were recruited; 37 had evidence of rejection on biopsy and 20 required treatment. As much as 11 patients needed inpatient treatment for rejection. HS-cfDNA significantly outperformed LFTs in identifying patients with tBPAR, particularly those needing inpatient treatment (area under the curve, 73.0%; 95% confidence interval, 55.4%-90.6%; P = 0.01). At a threshold of <33.5% of the total cfDNA fraction, HS-cfDNA had a specificity of 97%, correctly excluding tBPAR in 30/31 patients. Quantifying graft-specific methylation in cfDNA has a major advantage over previous gdcfDNA techniques: it does not require genotyping/sequencing, lending it greater feasibility for translation into transplantation care. Low levels of HS-cfDNA were a strong negative predictor for tBPAR (negative predictive value, 86%) and may have a future role in triaging patients prior to invasive graft biopsies.

A Synthetic DNA Construct to Evaluate the Recovery Efficiency of Cell-Free DNA Extraction and Bisulfite Modification.

BACKGROUND: Despite improvements in the genetic and epigenetic analysis of cell-free DNA (cfDNA), there has been limited focus on assessing the preanalytical variables of recovery efficiency following cfDNA extraction and bisulfite modification. Quantification of recovery efficiency after these steps can facilitate quality assurance and improve reliability when comparing serial samples. METHODS: We developed an exogenous DNA Construct to Evaluate the Recovery Efficiency of cfDNA extraction and BISulfite modification (CEREBIS) after cfDNA extraction and/or subsequent bisulfite modification from plasma. The strategic placement of cytosine bases in the 180 bp CEREBIS enabled PCR amplification of the construct by a single primer set both after plasma DNA extraction and following subsequent bisulfite modification. RESULTS: Plasma samples derived from 8 organ transplant donors and 6 serial plasma samples derived from a liver transplant recipient were spiked with a known number of copies of CEREBIS. Recovery of CEREBIS after cfDNA extraction and bisulfite modification was quantified with high analytical accuracy by droplet digital PCR. The use of CEREBIS and quantification of its recovery was useful in identifying problematic extractions. Furthermore, its use was shown to be invaluable towards improving the reliability of the analysis of serial samples. CONCLUSIONS: CEREBIS can be used as a spike-in control to address the preanalytical variable of recovery efficiency both after cfDNA extraction from plasma and following bisulfite modification. Our approach can be readily implemented and its application may have significant benefits, especially in settings where longitudinal quantification of cfDNA for disease monitoring is necessary.

Donor-specific cell-free DNA as a biomarker in liver transplantation: A review.

Due to advances in modern medicine, liver transplantation has revolutionised the prognosis of many previously incurable liver diseases. This progress has largely been due to advances in immunosuppressant therapy. However, despite the judicious use of immunosuppression, many liver transplant recipients still experience complications such as rejection, which necessitates diagnosis via invasive liver biopsy. There is a clear need for novel, minimally-invasive tests to optimise immunosuppression and improve patient outcomes. An emerging biomarker in this ''precision medicine'' liver transplantation field is that of donor-specific cell free DNA. In this review, we detail the background and methods of detecting this biomarker, examine its utility in liver transplantation and discuss future research directions that may be most impactful.