Publications by authors named "Jack Pang"

18 Publications

  • Page 1 of 1

Impact of switching from digital mammography to tomosynthesis plus digital mammography on breast cancer screening in Alberta, Canada.

J Med Screen 2021 Jul 16:9691413211032265. Epub 2021 Jul 16.

Department of Provincial Population and Public Health, Alberta Health Services, Edmonton, Alberta, Canada.

Objectives: To compare abnormal call rates (ACR), cancer detection rates (CDR), positive predictive values (PPVs), and annual return to screen recommendations after switching from digital mammography (DM) to digital breast tomosynthesis plus DM (DBT + DM) for breast cancer screening.

Setting: The Alberta Breast Cancer Screening Program collects screening data from clinics throughout the province of Alberta, Canada.

Methods: This study retrospectively collected data, between 2015 and 2018, on women aged 40+ who underwent breast cancer screening at two large volume multisite radiology groups to compare metrics one year prior and one year after DBT + DM implementation. Comparisons between modalities were carried out within age groups, within breast density categories, and for initial vs. subsequent screens.

Results: A total of 125,432 DM and 128,912 DBT + DM screening exams were performed. For women aged 50-74, the DBT + DM group had a higher ACR ( < 0.01) but lower annual return to screens ( < 0.01). CDR was higher post-DBT + DM implementation for women with scattered (6.0 per 1000 vs. 4.4 per 1000;  = 0.001) or heterogeneously dense breasts (6.5 per 1000 vs. 4.2 per 1000;  < 0.001). PPV was higher with DBT + DM for all age groups, with women 50-74 having a PPV of 8.3% using DBT + DM vs. 7.1% with DM ( = 0.009).

Conclusion: All metrics improved or stayed the same after switching to DBT + DM except for ACR. However, the increase in ACR could be attributed to a trend already occurring prior to the switch. Longer term monitoring is needed to confirm these findings.
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July 2021

COVID-19 infection among international travellers: a prospective analysis.

BMJ Open 2021 06 24;11(6):e050667. Epub 2021 Jun 24.

Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada

Objectives: This report estimates the risk of COVID-19 importation and secondary transmission associated with a modified quarantine programme in Canada.

Design And Participants: Prospective analysis of international asymptomatic travellers entering Alberta, Canada.

Interventions: All participants were required to receive a PCR COVID-19 test on arrival. If negative, participants could leave quarantine but were required to have a second test 6 or 7 days after arrival. If the arrival test was positive, participants were required to remain in quarantine for 14 days.

Main Outcome Measures: Proportion and rate of participants testing positive for COVID-19; number of cases of secondary transmission.

Results: The analysis included 9535 international travellers entering Alberta by air (N=8398) or land (N=1137) that voluntarily enrolled in the Alberta Border Testing Pilot Programme (a subset of all travellers); most (83.1%) were Canadian citizens. Among the 9310 participants who received at least one test, 200 (21.5 per 1000, 95% CI 18.6 to 24.6) tested positive. Sixty-nine per cent (138/200) of positive tests were detected on arrival (14.8 per 1000 travellers, 95% CI 12.5 to 17.5). 62 cases (6.7 per 1000 travellers, 95% CI 5.1 to 8.5; 31.0% of positive cases) were identified among participants that had been released from quarantine following a negative test result on arrival. Of 192 participants who developed symptoms, 51 (26.6%) tested positive after arrival. Among participants with positive tests, four (2.0%) were hospitalised for COVID-19; none required critical care or died. Contact tracing among participants who tested positive identified 200 contacts; of 88 contacts tested, 22 were cases of secondary transmission (14 from those testing positive on arrival and 8 from those testing positive thereafter). SARS-CoV-2 B.1.1.7 lineage was not detected in any of the 200 positive cases.

Conclusions: 21.5 per 1000 international travellers tested positive for COVID-19. Most (69%) tested positive on arrival and 31% tested positive during follow-up. These findings suggest the need for ongoing vigilance in travellers testing negative on arrival and highlight the value of follow-up testing and contact tracing to monitor and limit secondary transmission where possible.
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June 2021

Improving follow-up testing in children with Shiga toxin-producing Escherichia coli through provision of a provider information sheet.

Aust J Prim Health 2020 Dec;26(6):479-483

Population, Public, and Indigenous Health, Alberta Health Services, Calgary, AB T2N 1N4, Canada.

The aim of this study was to improve follow-up laboratory testing for children infected by Shiga toxin-producing Escherichia coli (STEC) through the provision of an information sheet to healthcare providers in the province of Alberta, Canada. An information sheet recommending the performance of laboratory tests, every 24-48h until 3 days after diarrhoea resolves or the platelet count stabilises or begins to rise, was sent to all physicians who ordered a STEC-positive stool test as of 1 November 2016. The information sheet was only distributed to physicians in one of the province's five healthcare delivery zones (i.e. intervention zone). Medical records for children aged <18 years with laboratory confirmed STEC-positive stool samples between November 2014 and November 2018 were reviewed to determine the performance of recommended laboratory tests. Post-intervention, follow-up testing in all categories increased significantly for cases that occurred in the intervention zone, with odds ratios (OR) ranging from 3.02 (95% CI: 1.35-6.78) to 3.94 (95% CI: 1.70-9.16) when compared with pre-intervention. No increase in any of the laboratory testing categories was detected outside of the intervention zone. The provision of a targeted information sheet to healthcare providers improved the monitoring of STEC-infected children.
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December 2020

Lisfranc Fixation Techniques and Postoperative Functional Outcomes: A Systematic Review.

J Foot Ankle Surg 2021 Jan-Feb;60(1):102-108. Epub 2020 Oct 8.

Consultant Orthopaedic Surgeon, Bendigo Base Hospital, Bendigo, Victoria, Australia.

The optimal method of fixation of acute Lisfranc injuries is yet to be established. We aim to systematically review the literature to identify the impact of fixation method on postoperative functional outcomes. A systematic review was undertaken using the PRISMA framework to identify all studies reporting postoperative functional outcomes in patients who underwent open-reduction internal fixation of acute Lisfranc injuries. Studies reporting outcomes of numerous fixation methods were divided into fixation subcohorts. Studies comparing bridge plate with transarticular screw fixation were included for meta-analysis, conducted using a random-effects model. Seventeen studies (20 subcohorts) with 462 patients were included. Mean patient age was 29.6 (rang, 15-81) years. Mean follow-up was 38.7 (range 11 to 287) months. American Academy of Orthopaedic Surgeons midfoot score (AOFAS-MF) was the most frequently reported functional outcome (16/20 subcohorts). Overall weighted mean AOFAS-MF was 76.3 ± 9.4 for all cases, with 74.2 ± 9.4 for transarticular screws and 79.2 ± 8.3 for bridge plates. The mean difference between screw and plate was not statistically significant (mean difference = 5.0, 95% confidence interval, -4.8 - 14.8, p = .3). A single study reported AOFAS-MF mean of 92 using suture button fixation. Meta-analysis of the 2 available comparative studies revealed higher postoperative AOFAS-MF with bridge plate fixation (pooled standardized mean difference, 0.51; 95% confidence interval, 0.15-0.87, p = .006). There is scarcity of literature examining the impact of fixation method on postoperative functional outcomes in acute Lisfranc injuries. A small number of studies have reported superior functional outcomes with use of bridge plate fixation. Further evidence is needed to ascertain which injuries are best managed with each fixation method or whether 1 fixation construct is universally superior.
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June 2021

Differential Effect of Genetic Burden on Disease Phenotypes in Crohn's Disease and Ulcerative Colitis in a Canadian Cohort.

J Can Assoc Gastroenterol 2021 Apr 3;4(2):65-72. Epub 2020 Feb 3.

Division of Gastroenterology, University of Calgary, Calgary, Alberta, Canada.

Background And Aims: Crohn's disease (CD) and ulcerative colitis (UC) demonstrate considerable phenotypic heterogeneity and course. Accurate predictors of disease behaviour are lacking. The contribution of genetics and specific polymorphisms is widely appreciated; however, their cumulative effect(s) upon disease behaviour remains poorly understood. Here, we investigate the relationship between genetic burden and disease phenotype in a Canadian inflammatory bowel disease (IBD) Cohort.

Methods: We retrospectively examined a cohort of CD and UC patients recruited from a single tertiary referral center genotyped using a Goldengate Illumina platform. A genetic risk score (GRS) incorporating strength of association (log odds ratio) and allele dose for 151 IBD-risk loci was calculated and evaluated for phenotypic associations.

Results: Among CD patients, higher GRS was associated with earlier onset of disease (regression coefficient -2.19, 95% confidence interval [CI] -3.77 to -0.61, = 0.007), ileal disease (odds ratio [OR] 1.45), stricturing/penetrating disease (OR 1.72), perianal disease (OR 1.57) and bowel resection (OR 1.66). Higher GRS was associated with use of anti-tumor necrosis factor (TNF) ( < 0.05) but not immunomodulators. Interestingly, we could not demonstrate an association between higher GRS and family history of IBD (OR 1.27, = 0.07). Onset of disease remained statistically significant for never smokers ( = 0.03) but not ever smokers ( = 0.13). For UC, having a higher GRS did not predict the age of diagnosis nor was it predictive of UC disease extent ( = 0.18), the need for surgery ( = 0.74), nor medication use (immunomodulators = 0.53, anti-TNF = 0.49). We could not demonstrate an association between increased GRS and having a family history of IBD in the UC group.

Conclusions: Increasing genetic burden is associated with early age of diagnosis in CD and may be useful in predicting disease behaviour in CD but not UC.
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April 2021

Preoperative Ustekinumab Treatment Is Not Associated With Increased Postoperative Complications in Crohn's Disease: A Canadian Multi-Centre Observational Cohort Study.

J Can Assoc Gastroenterol 2018 Sep 10;1(3):115-123. Epub 2018 May 10.

Division of Gastroenterology and Hepatology, University of Calgary, Calgary, Canada.

Background: Ustekinumab (UST), an anti-IL12/23 inhibitor is indicated for moderate-to-severe Crohn's disease (CD). However, it is unclear if patients treated with UST are at increased risk for postoperative complications.

Aim: To evaluate the postoperative safety outcomes in UST-treated CD patients.

Methods: A multicentre cohort study of UST-treated CD patients at two tertiary care centres (University of Calgary, University of Alberta, Canada) undergoing abdominal surgery between 2009 and 2016 was performed. Postoperative outcomes were compared against a control cohort of anti-TNF-treated patients over the same time-period. The primary outcome was occurrence of postoperative complications up to six months postoperatively, stratified by timing (early <30 days vs. late complications ≥30 days).

Results: Twenty UST-treated patients and 40 anti-TNF-treated patients were included with a median preoperative treatment exposure of 6.5 months and 18 months, respectively (p=0.01). Bowel obstruction was the most common surgical indication in both cohorts. UST-treated patients were more likely to require an ostomy (70.0% vs. 12.5%, p<0.001) and be on combination therapy with either systemic corticosteroids or concurrent immunomodulators (azathioprine or methotrexate) (25.0% vs. 2.5%, p=0.01). Despite the increased concomitant use of immunosuppression in the UST-treated cohort, there were no significant differences in early or late postoperative wound infections (1/20 in UST-cohort, 2/40 in anti-TNF cohort, p=1.00), anastomotic leak (0/20 in UST-cohort, 3/40 in anti-TNF cohort, p=0.54), or postoperative ileus/obstruction (3/20 in UST-cohort, 4/40 in anti-TNF cohort, p=0.67).

Conclusions: CD patients receiving preoperative UST did not experience an increase in postoperative complications, despite increased use of concurrent immunosuppression.
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September 2018

Primary biliary cholangitis patients exhibit MRI changes in structure and function of interoceptive brain regions.

PLoS One 2019 8;14(2):e0211906. Epub 2019 Feb 8.

Seaman Family MR Research Centre, University of Calgary, Calgary, Alberta, Canada.

Background: Many patients with primary biliary cholangitis (PBC) experience non-hepatic symptoms that are possibly linked to altered interoception, the sense of the body's internal state. We used magnetic resonance imaging (MRI) to determine if PBC patients exhibit structural and functional changes of the thalamus and insula, brain regions that process signals related to interoception.

Methods: Fifteen PBC patients with mild disease and 17 controls underwent 3 Tesla T1-weighted MRI, resting-state functional MRI, and quantitative susceptibility mapping (QSM), to measure thalamic and insular volume, neuronal activity and iron deposition, respectively. Group differences were assessed using analysis of covariance, and stepwise linear regression was used to determine the predictive power of clinical indicators of disease.

Results: PBC patients exhibited reduced thalamic volume (p < 0.01), and ursodeoxycholic acid (UDCA) non-responders exhibited lower left thalamus activity (p = 0.05). PBC patients also exhibited reduced anterior insula activity (p = 0.012), and liver stiffness positively correlated with MRI indicators of anterior insula iron deposition (p < 0.02).

Conclusions: PBC affects structure and function of brain regions critically important to interoception. Moreover, these brain changes occur in patients with early, milder disease and thus may potentially be reversible.
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November 2019

Magnetic resonance imaging evidence of hippocampal structural changes in patients with primary biliary cholangitis.

Clin Transl Gastroenterol 2018 07 6;9(7):169. Epub 2018 Jul 6.

Seaman Family MR Research Centre, University of Calgary, Calgary, AB, Canada.

Introduction: Behavioral symptoms are commonly reported by patients with primary biliary cholangitis (PBC). In other patient populations, symptoms are commonly associated with hippocampal volume reduction linked to neuroinflammation (inferred from regional iron deposition), as demonstrated by magnetic resonance imaging (MRI). We hypothesized that PBC patients would exhibit reduced volume and increased iron deposition of the hippocampus.

Methods: Seventeen female non-cirrhotic PBC patients and 17 age/gender-matched controls underwent 3-Tesla T-weighted MRI and quantitative susceptibility mapping (QSM; an indicator of iron deposition). The hippocampus and its subfields were segmented from T images using Freesurfer, and susceptibility of the whole hippocampus was calculated from QSM images. Volume and susceptibility were compared between groups, and associations with PBC-40 score and disease indicators (years since diagnosis, Fibroscan value, alkaline phosphatase level, clinical response to ursodeoxycholic acid (UDCA)) were investigated.

Results: PBC patients exhibited significantly reduced hippocampal volume (p = 0.023) and increased susceptibility (p = 0.048). Subfield volumes were reduced for the subiculum, molecular layer, granule cell layer of the dentate gyrus and CA4 (p < 0.05). Fibroscan value was significantly correlated with PBC-40 (Spearman's rho = 0.499; p = 0.041) and disease duration (Spearman's rho = 0.568; p = 0.017).

Discussion: Our findings suggest hippocampal changes occur early in the disease course of PBC, similar in magnitude to those observed in major depressive disorder and neurodegenerative diseases.

Translational Impact: Clinical management of PBC could include early interventional strategies that promote hippocampal neurogenesis that may beneficially impact behavioral symptoms and improve quality of life.
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July 2018

Primary Biliary Cholangitis Alters Functional Connections of the Brain's Deep Gray Matter.

Clin Transl Gastroenterol 2017 Jul 27;8(7):e107. Epub 2017 Jul 27.

Seaman Family MR Research Centre, University of Calgary, Calgary, Alberta, Canada.

Objectives: Fatigue, itch, depressed mood, and cognitive impairment significantly impact the quality of life of many patients with primary biliary cholangitis (PBC). Previous neuroimaging studies of non-hepatic diseases suggest that these symptoms are often associated with dysfunction of deep gray matter brain regions. We used resting-state functional magnetic resonance imaging (rsfMRI) to determine whether PBC patients exhibit altered functional connections of deep gray matter.

Methods: Twenty female non-cirrhotic PBC patients and 21 age/gender-matched controls underwent rsfMRI. Resting-state functional connectivity (rsFC) of deep gray matter brain structures (putamen, thalamus, amygdala, hippocampus) was compared between groups. Fatigue, itch, mood, cognitive performance, and clinical response to ursodeoxycholic acid (UDCA) were assessed, and their association with rsFC was determined.

Results: Relative to controls, PBC patients exhibited significantly increased rsFC between the putamen, thalamus, amygdala, and hippocampus, as well as with frontal and parietal regions. Reduced rsFC of the putamen and hippocampus with motor and sensory regions of the brain were also observed. Fatigue, itch, complete response to UDCA, and verbal working memory performance were also associated with altered rsFC of deep gray matter. These rsFC changes were independent of biochemical disease severity.

Conclusions: PBC patients have objective evidence of altered rsFC of the brain's deep gray matter that is in part linked to fatigue severity, itch, response to UDCA therapy, and cognitive performance. These results may guide future approaches to define how PBC leads to altered brain connectivity and provide insight into novel targets for treating PBC-associated brain dysfunction and behavioral symptoms.
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July 2017

Treatment outcomes with telaprevir-based therapy for HIV/hepatitis C coinfected patients are comparable with hepatitis C monoinfected patients.

Can J Infect Dis Med Microbiol 2015 Nov-Dec;26(6):293-6

Calgary Liver Unit, Division of Gastroenterology and Hepatology, University of Calgary Cumming School of Medicine; Southern Alberta Clinic; Department of Microbiology, Immunology and Infectious Diseases, University of Calgary Cumming School of Medicine, Calgary, Alberta.

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January 2016

Validation of coding algorithms for the identification of patients hospitalized for alcoholic hepatitis using administrative data.

BMC Gastroenterol 2015 Sep 11;15:116. Epub 2015 Sep 11.

Liver Unit, Division of Gastroenterology and Hepatology, University of Calgary, Calgary, AB, Canada.

Background: Epidemiologic studies of alcoholic hepatitis (AH) have been hindered by the lack of a validated International Classification of Disease (ICD) coding algorithm for use with administrative data. Our objective was to validate coding algorithms for AH using a hospitalization database.

Methods: The Hospital Discharge Abstract Database (DAD) was used to identify consecutive adults (≥18 years) hospitalized in the Calgary region with a diagnosis code for AH (ICD-10, K70.1) between 01/2008 and 08/2012. Medical records were reviewed to confirm the diagnosis of AH, defined as a history of heavy alcohol consumption, elevated AST and/or ALT (<300 U/L), serum bilirubin >34 μmol/L, and elevated INR. Subgroup analyses were performed according to the diagnosis field in which the code was recorded (primary vs. secondary) and AH severity. Algorithms that incorporated ICD-10 codes for cirrhosis and its complications were also examined.

Results: Of 228 potential AH cases, 122 patients had confirmed AH, corresponding to a positive predictive value (PPV) of 54% (95% CI 47-60%). PPV improved when AH was the primary versus a secondary diagnosis (67% vs. 21%; P < 0.001). Algorithms that included diagnosis codes for ascites (PPV 75%; 95% CI 63-86%), cirrhosis (PPV 60%; 47-73%), and gastrointestinal hemorrhage (PPV 62%; 51-73%) had improved performance, however, the prevalence of these diagnoses in confirmed AH cases was low (29-39%).

Conclusions: In conclusion the low PPV of the diagnosis code for AH suggests that caution is necessary if this hospitalization database is used in large-scale epidemiologic studies of this condition.
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September 2015

Inclusion of Sarcopenia Within MELD (MELD-Sarcopenia) and the Prediction of Mortality in Patients With Cirrhosis.

Clin Transl Gastroenterol 2015 Jul 16;6:e102. Epub 2015 Jul 16.

1] Liver Unit, Division of Gastroenterology and Hepatology, University of Calgary, Calgary, Alberta, Canada [2] Department of Community Health Sciences, University of Calgary, Calgary, Alberta, Canada.

Objectives: Limitations of the Model for End-Stage Liver Disease (MELD) score include its failure to assess the nutritional and functional status of cirrhotic patients. Our objectives were to evaluate the impact of sarcopenia in cirrhosis and whether the inclusion of muscularity assessment within MELD could improve the prediction of mortality in patients with cirrhosis.

Methods: We included 669 cirrhotic patients who were consecutively evaluated for liver transplantation. Skeletal muscle index at the third lumbar vertebra (L3 SMI) was measured by computed tomography, and sarcopenia was defined using previously published gender and body mass index-specific cutoffs. Using Cox proportional hazards regression, a novel MELD-sarcopenia score was derived.

Results: Sarcopenia was present in 298 patients (45%); sarcopenic patients had shorter median survival than non-sarcopenic patients (20±3 vs. 95±24 months, P<0.001). By Cox regression analysis adjusted for age, gender, and hepatocellular carcinoma, both MELD (hazard ratio (HR) 1.08, 95% confidence interval (CI) 1.06-1.10, P<0.001), and the L3 SMI (HR 0.97, 95% CI 0.96-0.99, P<0.001) were associated with mortality. Overall, the c-statistics for 3-month mortality were 0.82 (95% CI 0.78-0.87) for MELD and 0.85 (95% CI 0.81-0.88) for MELD-sarcopenia (P=0.1). Corresponding figures for 1-year mortality were 0.73 (95% CI 0.69-0.77) and 0.77 (95% CI 0.73-0.80), respectively (P=0.03). The c-statistics for 3-month mortality in patients with MELD<15 (0.85 vs. 0.69, P=0.02) and refractory ascites (0.74 vs. 0.71, P=0.01) were significantly higher for MELD-sarcopenia compared with MELD.

Conclusions: Modification of MELD to include sarcopenia is associated with improved prediction of mortality in patients with cirrhosis, primarily in patients with low MELD scores. External validation of this prognostic index in larger cohorts of cirrhotic patients is warranted.
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July 2015

Risk factors for mortality in patients with alcoholic hepatitis and assessment of prognostic models: A population-based study.

Can J Gastroenterol Hepatol 2015 Apr;29(3):131-8

Background: Severe alcoholic hepatitis (AH) is associated with a substantial risk for short-term mortality.

Objectives: To identify prognostic factors and validate well-known prognostic models in a Canadian population of patients hospitalized for AH.

Methods: In the present retrospective study, patients hospitalized for AH in Calgary, Alberta, between January 2008 and August 2012 were included. Stepwise logistic regression models identified independent risk factors for 90-day mortality, and the discrimination of prognostic models (Model for End-stage Liver Disease [MELD] and Maddrey discriminant function [DF]) were examined using areas under the ROC curves.

Results: A total of 122 patients with AH were hospitalized during the study period; the median age was 49 years (interquartile range [IQR] 42 to 55 years) and 60% were men. Median MELD score and Maddrey DF on admission were 21 (IQR 18 to 24) and 45 (IQR 26 to 62), respectively. Seventy-three percent of patients received corticosteroids and⁄or pentoxifylline, and the 90-day mortality was 17%. Independent predictors of mortality included older age, female sex, international normalized ratio, MELD score and Maddrey DF (all P<0.05). For discrimination of 90-day mortality, the areas under the ROC curves of the prognostic models (MELD 0.64; Maddrey DF 0.68) were similar (P>0.05). At optimal cut-offs of ≥22 for MELD score and ≥37 for Maddrey DF, both models excluded death with high certainty (negative predictive values 90% and 96%, respectively).

Conclusions: In patients hospitalized for AH, well-known prognostic models can be used to predict 90-day mortality, particularly to identify patients with a low risk for death.
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April 2015

Liver stiffness by transient elastography predicts liver-related complications and mortality in patients with chronic liver disease.

PLoS One 2014 22;9(4):e95776. Epub 2014 Apr 22.

Liver Unit, Division of Gastroenterology and Hepatology, Department of Medicine, University of Calgary, Calgary, Alberta, Canada; Department of Community Health Sciences, University of Calgary, Calgary, Alberta, Canada.

Background: Liver stiffness measurement (LSM) by transient elastography (TE, FibroScan) is a validated method for noninvasively staging liver fibrosis. Most hepatic complications occur in patients with advanced fibrosis. Our objective was to determine the ability of LSM by TE to predict hepatic complications and mortality in a large cohort of patients with chronic liver disease.

Methods: In consecutive adults who underwent LSM by TE between July 2008 and June 2011, we used Cox regression to determine the independent association between liver stiffness and death or hepatic complications (decompensation, hepatocellular carcinoma, and liver transplantation). The performance of LSM to predict complications was determined using the c-statistic.

Results: Among 2,052 patients (median age 51 years, 65% with hepatitis B or C), 87 patients (4.2%) died or developed a hepatic complication during a median follow-up period of 15.6 months (interquartile range, 11.0-23.5 months). Patients with complications had higher median liver stiffness than those without complications (13.5 vs. 6.0 kPa; P<0.00005). The 2-year incidence rates of death or hepatic complications were 2.6%, 9%, 19%, and 34% in patients with liver stiffness <10, 10-19.9, 20-39.9, and ≥40 kPa, respectively (P<0.00005). After adjustment for potential confounders, liver stiffness by TE was an independent predictor of complications (hazard ratio [HR] 1.05 per kPa; 95% confidence interval [CI] 1.03-1.06). The c-statistic of liver-stiffness for predicting complications was 0.80 (95% CI 0.75-0.85). A liver stiffness below 20 kPa effectively excluded complications (specificity 93%, negative predictive value 97%); however, the positive predictive value of higher results was sub-optimal (20%).

Conclusions: Liver stiffness by TE accurately predicts the risk of death or hepatic complications in patients with chronic liver disease. TE may facilitate the estimation of prognosis and guide management of these patients.
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January 2015

The feasibility and reliability of transient elastography using Fibroscan®: a practice audit of 2335 examinations.

Can J Gastroenterol Hepatol 2014 Mar;28(3):143-9

Background: Liver stiffness measurement (LSM) using transient elastography is widely used in the management of patients with chronic liver disease.

Objectives: To examine the feasibility and reliability of LSM, and to identify patient and operator characteristics predictive of poorly reliable results.

Methods: The present retrospective study investigated the frequency and determinants of poorly reliable LSM (interquartile range [IQR]⁄median LSM [IQR⁄M] >30% with median liver stiffness ≥7.1 kPa) using the FibroScan (Echosens, France) over a three-year period. Two experienced operators performed all LSMs. Multiple logistic regression analyses examined potential predictors of poorly reliable LSMs including age, sex, liver disease, the operator, operator experience (<500 versus ≥500 scans), FibroScan probe (M versus XL), comorbidities and liver stiffness. In a subset of patients, medical records were reviewed to identify obesity (body mass index ≥30 kg⁄m2).

Results: Between July 2008 and June 2011, 2335 patients with liver disease underwent LSM (86% using the M probe). LSM failure (no valid measurements) occurred in 1.6% (n=37) and was more common using the XL than the M probe (3.4% versus 1.3%; P=0.01). Excluding LSM failures, poorly reliable LSMs were observed in 4.9% (n=113) of patients. Independent predictors of poorly reliable LSM included older age (OR 1.03 [95% CI 1.01 to 1.05]), chronic pulmonary disease (OR 1.58 [95% CI 1.05 to 2.37), coagulopathy (OR 2.22 [95% CI 1.31 to 3.76) and higher liver stiffness (OR per kPa 1.03 [95% CI 1.02 to 1.05]), including presumed cirrhosis (stiffness ≥12.5 kPa; OR 5.24 [95% CI 3.49 to 7.89]). Sex, diabetes, the underlying liver disease and FibroScan probe were not significant. Although reliability varied according to operator (P<0.0005), operator experience was not significant. In a subanalysis including 434 patients with body mass index data, obesity influenced the rate of poorly reliable results (OR 2.93 [95% CI 0.95 to 9.05]; P=0.06).

Conclusions: FibroScan failure and poorly reliable LSM are uncommon. The most important determinants of poorly reliable results are older age, obesity, higher liver stiffness and the operator, the latter emphasizing the need for adequate training.
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March 2014

Transjugular intrahepatic portosystemic shunt vs endoscopic therapy in preventing variceal rebleeding.

World J Gastroenterol 2012 Dec;18(48):7341-7

Department of Gastroenterology, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, Shaanxi Province, China.

Aim: To compare early use of transjugular intrahepatic portosystemic shunt (TIPS) with endoscopic treatment (ET) for the prophylaxis of recurrent variceal bleeding.

Methods: In-patient data were collected from 190 patients between January 2007 and June 2010 who suffured from variceal bleeding. Patients who were older than 75 years; previously received surgical treatment or endoscopic therapy for variceal bleeding; and complicated with hepatic encephalopathy or hepatic cancer, were excluded from this research. Thirty-five cases lost to follow-up were also excluded. Retrospective analysis was done in 126 eligible cases. Among them, 64 patients received TIPS (TIPS group) while 62 patients received endoscopic therapy (ET group). The relevant data were collected by patient review or telephone calls. The occurrence of rebleeding, hepatic encephalopathy or other complications, survival rate and cost of treatment were compared between the two groups.

Results: During the follow-up period (median, 20.7 and 18.7 mo in TIPS and ET groups, respectively), rebleeding from any source occurred in 11 patients in the TIPS group as compared with 31 patients in the ET group (Kaplan-Meier analysis and log-rank test, P = 0.000). Rebleeding rates at any time point (6 wk, 1 year and 2 year) in the TIPS group were lower than in the ET group (Bonferroni correction α' = α/3). Eight patients in the TIPS group and 16 in the ET group died with the cumulative survival rates of 80.6% and 64.9% (Kaplan-Meier analysis and log-rank test χ(2) = 4.864, P = 0.02), respectively. There was no significant difference between the two groups with respect to 6-wk survival rates (Bonferroni correction α' = α/3). However, significant differences were observed between the two groups in the 1-year survival rates (92% and 79%) and the 2-year survival rates (89% and 64.9%) (Bonferroni correction α' = α/3). No significant differences were observed between the two treatment groups in the occurrence of hepatic encephalopathy (12 patients in TIPS group and 5 in ET group, Kaplan-Meier analysis and log-rank test, χ(2) = 3.103, P = 0.08). The average total cost for the TIPS group was higher than for ET group (Wilcxon-Mann Whitney test, 52 678 RMB vs 38,844 RMB, P < 0.05), but hospitalization frequency and hospital stay during follow-up period were lower (Wilcxon-Mann Whitney test, 0.4 d vs 1.3 d, P = 0.01; 5 d vs 19 d, P < 0.05).

Conclusion: Early use of TIPS is more effective than endoscopic treatment in preventing variceal rebleeding and improving survival rate, and does not increase occurrence of hepatic encephalopathy.
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December 2012

The arterial supply of the patellar tendon: anatomical study with clinical implications for knee surgery.

Clin Anat 2009 Apr;22(3):371-6

Jack Brockhoff Reconstructive Plastic Surgery Research Unit, Department of Anatomy and Cell Biology, University of Melbourne, Parkville, Victoria, Australia.

The middle-third of the patellar tendon (PT) is well-established as a potential graft for cruciate ligament reconstruction, but there is little anatomical basis for its use. Although studies on PT vascular anatomy have focused on the risk to tendon pedicles from surgical approaches and knee pathophysiology, the significance of its blood supply to grafting has not been adequately explored previously. This investigation explores both the intrinsic and extrinsic arterial anatomy of the PT, as relevant to the PT graft. Ten fresh cadaveric lower limbs underwent angiographic injection of the common femoral artery with radio-opaque lead oxide. Each tendon was carefully dissected, underwent plain radiography and subsequently schematically reconstructed. The PT demonstrated a well-developed and consistent vascularity from three main sources: antero-proximally, mainly by the inferior-lateral genicular artery; antero-distally via a choke-anastomotic arch between the anterior tibial recurrent and inferior medial genicular arteries; and posteriorly via the retro-patellar anastomotic arch in Hoffa's fat pad. Two patterns of pedicles formed this arch: inferior-lateral and descending genicular arteries (Type-I); superior-lateral, inferior-lateral, and superior-medial genicular arteries (Type-II). Both types supplied the posterior PT, with the majority of vessels descending to its middle-third. The middle-third PT has a richer intrinsic vascularity, which may enhance its ingrowth as a graft, and supports its conventional use in cruciate ligament reconstruction. The pedicles supplying the PT are endangered during procedures where Hoffa's fat pad is removed including certain techniques of PT harvest and total knee arthroplasty.
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April 2009

A comparative anatomical study of brachioradialis and flexor carpi ulnaris muscles: implications for total tongue reconstruction.

Plast Reconstr Surg 2008 Mar;121(3):816-829

Melbourne, Victoria, Australia From the Jack Brockhoff Reconstructive Plastic Surgery Research Unit, Royal Melbourne Hospital, Department of Anatomy and Cell Biology, University of Melbourne.

Background: Total or subtotal glossectomy following resection of intraoral tumors causes significant morbidity. Recent surgical endeavors have focused on the creation of a neotongue with both sensory and motor innervation. Although various local or regional free flaps have been used for this purpose, the optimal donor site remains undecided. The authors compared the neurovascular anatomy of the brachioradialis and flexor carpi ulnaris to assess their suitability as donor muscles together with overlying skin for functional total or subtotal tongue reconstruction.

Methods: Eighty-eight brachioradialis and 80 flexor carpi ulnaris muscles were studied, comprising 120 dissected specimens, 18 arterial studies, two venous studies, 20 histologic studies, and eight neurovascular studies.

Results: The dominant vascular pattern of the brachioradialis varied. The major pedicle arose from the radial (38 percent), radial recurrent (42 percent), and brachial arteries (20 percent). The muscle also lacked a single neurovascular pedicle. The vasculature of the flexor carpi ulnaris was consistent. The ulnar artery supplied the dominant pedicle in 86 percent of cases. The entry point of motor innervation is near that of the vascular pedicles. A minor distal nerve accompanied the main vascular pedicle in 65 percent of cases. The overlying skin was supplied by musculocutaneous perforators. The lower lateral cutaneous nerve of the arm supplied the skin over the brachioradialis, and the medial cutaneous nerves of the arm and forearm provided sensation over the flexor carpi ulnaris.

Conclusion: The authors delineated the anatomical advantages of the flexor carpi ulnaris over the brachioradialis for total or subtotal tongue reconstruction.
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March 2008