Socio-Economic Status in Risk of Acute Adverse Events Following Radiotherapy

PURPOSE/OBJECTIVE(S)

Socio-economic status (SES) are known to influence cancer patient outcomes. The purpose of this study is to evaluate whether SES affected the short-term clinical experience of patients treated with radiotherapy (RT) during the pandemic.

MATERIALS/METHODS

This was a single institution, retrospective cohort quality improvement study. The primary endpoint consisted of adverse events (AEs) defined as an unplanned admission to a drop-in radiation-nursing clinic (RNC) or the institution's emergency department (ED) within 90 days of a radiation course. Adult cancer patients who received external beam RT from April 1, 2019, to March 31, 2022 were included. Patients were classified into two periods: treated prior to the pandemic (pre-COVID), and during the pandemic (COVID era), with a cutoff date of March 31, 2020. SES, age, RT intent (curative, palliative, SBRT), regimen (conventional fractionation and hypofractionation), disease site, and sex were included as co-variables. SES was obtained by matching a patient's postal code with a provincial data tool with four distinct dimensions: 1) residential instability, 2) material deprivation, 3) ethnic concentration, and 4) dependency. For each SES dimension, a score of 1-5 (best-worst) is assigned to individuals. A backward stepwise multivariable logistic regression analysis was performed to analyze the variables and identify the factors that were significantly associated (p<0.05) with increased risk of AEs. Institutional ethics review board exemption was obtained.

RESULTS

Across the 3-year period, 15715 patients (5499 pre-COVID and 10216 COVID era patients) were identified and included in the analyses, and 5756 AEs were observed. The analyses revealed that patient age (p<0.001), disease site (p<0.001), treatment intent (p<0.001) and treatment regimen (p = 0.005) were associated with the risk of developing AEs. AEs risk was correlated with the treatment period (pre-COVID vs. COVID era) (p<0.001) and material deprivation (p = 0.027). Adjusting for the other variables, patients who were least materially deprived were at lower risk (Odds Ratio (OR) = 0.88, 95% CI [0.78-0.98]) of developing AEs than patients who were most materially deprived. Patient sex (p>0.1), residential instability (p = 0.069), ethnic concentration (p>0.5) and dependency (p>0.5) were not associated with AEs risk. Patients with more (SES score 1-4 vs 5) residential instability (p<0.001; OR = 0.82, 95% CI [0.74-0.90]) and less (SES score 1 vs 2-5) material deprivations (p = 0.006; OR = 0.76, 95% CI [0.66-0.88]) were at reduced the risk of ED visits. SES was not associated with RNC visits.

CONCLUSION

In a universal health care system, SES (residential instability and material deprivation) were associated with the increased risk of ED within 90 days of RT. Proactive care and virtual monitoring during the 90-day period after RT in high-risk patients may reduce ED visits. ED visits beyond our tertiary institution are being gathered to address this study limitation.

Brachytherapy-on-Chip: A Microfluidic Setup for In Vitro Interrogation of Hypoxic Spheroids

PURPOSE/OBJECTIVE(S)

Despite evidence of its advantages in many cancers, brachytherapy (BT) remains clinically underused and understudied in the pre-clinical setting due to a lack of versatile RT-compatible in vitro tools that can emulate the tumor microenvironment and radiobiology of various cancers. Microfluidic devices use conventional cell culture methods in 3D-tumor models, are radiocompatible and can integrate radiobioassays. However, they are seldom used in pre-clinical BT research. This project engineered the first microfluidic tool for in vitro testing of BT, with applications in translational radiobiology.

MATERIALS/METHODS

PDMS microfluidic chips were engineered to grow and culture concentric rows of hypoxic spheroids, and to allow the insertion of a clinical iodine-125 BT seed at the center of the device. FaDu (hypopharyngeal squamous cell carcinoma), SK-LMS-1 (leiomyosarcoma) and HCT116 (colorectal carcinoma) cell lines were selected for their clinical relevance and ability to form spheroids. Presence of hypoxia in spheroids was assessed by immunofluorescence (IF) staining for hypoxic protein CAIX. On-chip dose distribution was calculated using clinical TG-43 parameters and compared to EBT-XD radiographic film. Target dose criteria was fixed at 8 Gy in the center of the first row of spheroids. Treatment response was quantified by DNA damages (γH2AX IF, comet assay) and cell survival (clonogenic assay). Response of hypoxic and normoxic regions of spheroids will be compared in IF.

RESULTS

A total of 15 spheroids that are 750µm or larger can be cultured in our device, arranged as 5 rows of 3 spread from 1.5mm to 7.5mm away from a central iodine-125 seed. 48h after cell seeding, hypoxic cores were observed in spheroids derived from FaDu (50 ± 4% of cross-section, N = 3) and SK-LMS-1 (46 ± 4% of cross-section, N = 3) cells, results are pending for HCT116. TG-43 formula predicts that the center of each row receives 8 Gy, 2.6 Gy, 1.2 Gy, 0.7 Gy and 0.4 Gy respectively. Radiographic film analysis confirms on-chip TG-43 calculated doses (N = 5, R2 = 0.999). Similarly, tail moment from comet assays follows predicted dose trends (n>60, N = 3). There was no statistical difference between 8 Gy BT and 8 Gy GammaCell (8 Gy BT vs 8 Gy GammaCell, p = 0.8758), with a statistical difference between 8 Gy BT (8 Gy BT vs 2.6 Gy BT,1.2 Gy BT,0.7 Gy BT,0.4 Gy BT,0 Gy, p < 0.0001), 2.6 Gy BT (2.6 Gy BT vs 1.2 Gy BT,0.7 Gy BT,0.4 Gy BT,0 Gy, p < 0.05) or 8 Gy GammaCell (8 Gy GammaCell vs 2.6 Gy BT,1.2 Gy BT,0.7 Gy BT,0.4 Gy BT,0 Gy, p < 0.0001) and other lower BT doses.

CONCLUSION

For the first time, brachytherapy can be easily integrated on-chip and its effects evaluated on relevant 3D-tumor models. Our system allows simultaneous quantification of BT efficacy on normoxic and hypoxic cells treated at various doses. On-chip combination of BT with antitumor drug will be explored in future work. We hope this device will serve as further proof of the potential of BT/RT-on-chip systems for better drug development, treatment planification and theranostics.

Evaluating the Short-Term Environmental and Clinical Effects of a Radiation Oncology Department's Response to the COVID-19 Pandemic (STEER COVID-19)

Purpose/Objective(s)

During the COVID-19 pandemic, hypofractionated regimens and virtual care was adopted by our institution to preserve hospital capacity and reduce foot traffic. This study's primary objective was to assess the collective environmental impact of these strategic changes by identifying sources of carbon dioxide equivalents (CO₂e). As sustainable healthcare is only justifiable if the quality of the care is maintained, we also evaluated the rate of radiation-related acute adverse event.

Materials/Methods

All patients treated with external beam radiation therapy from April 1, 2019 to March 31, 2021 at our single institution were identified (n=10,175) along with their radiotherapy visits (176,423 fractions), and visits to the radiation nursing clinic (RNC) or emergency (ER) department. A treatment regimen was considered hypofractionated if the dose per fraction was ≥ 240 cGy. If the dose per fraction was ≥ 600 cGy and the total dose of the treatment regimen was > 2000 cGy, then the treatment regimen was classified as SBRT. Out-patient hospital and virtual visits (n=75,853) during this same period were also analyzed. Environmental impact measures, including linear accelerator power usage, patient travel distances, and personal protection equipment (PPE) consumption were all converted into CO₂e. A waiver of individual patient consent was granted for this study by our institution's Research Ethics Board (REB).

Results

The use of curative hypofractionated regimens increased from 17% to 27% during the pandemic year. Twelve out of 15 cancer sites increased their use of hypofractionated regimens. Carbon footprint was reduced by 39% during the pandemic year (1,332,388 kg CO₂e) as compared to the pre-pandemic year (2,024,823 kg CO₂e). For comparison, the 744 tonnes of CO₂e saved during the pandemic year equates to the CO₂e produced by the annual energy consumption of 182 Canadian households or the CO₂e sequestered by 12,000 seedling trees planted and grown for 10 years. On average 121 kg CO₂e and 100 kg CO₂e were emitted per radiation regimen delivered during the pre-pandemic and pandemic year, respectively. Comparing patients in the pre-pandemic vs. pandemic year, there was a significant reduction in the proportion of hypofractionated patients who needed a visit to either the RNC (39% vs. 25%; p<0.001) or ER (6% vs. 2%; p<0.001) during and within 90 days of radiotherapy.

Conclusion

This study demonstrated the environmental benefits of increased use of hypofractionated regimens and virtual care, while assuring that there was no added acute radiation-related adverse event. Our findings support their continued use as one of many long-term strategies to reduce the environmental footprint of healthcare delivery. Treatment efficacy and side-effects will need to be assessed in subsequent years to further support the sustainability of these strategies.

A224 COVID-19 INFECTION IN LIVER TRANSPLANT RECIPIENTS: CLINICAL FEATURES, HOSPITALIZATION, AND MORTALITY FROM A CANADIAN MULTICENTRE COHORT

Background

The COVID-19 pandemic has brought significant challenges to clinicians caring for liver transplant (LT) recipients. Researchers have sought to better understand the risk and clinical outcomes of LT recipients infected with COVID-19 globally, however, there is a paucity of data from within Canada.

Aims

Our multi-center study aims to examine the characteristics and clinical outcomes of LT patients with COVID-19 in Canada.

Methods

We identified a retrospective cohort of adult LT recipients with RT-PCR confirmed COVID-19 from 7 Canadian tertiary care centers between March 2020 and June 2021. Demographic and clinical data were compiled by clinicians within those centers. We identified liver enzyme profile at the time of COVID-19 infection, immunosuppression type and post-infection adjustments, rate of hospitalization, ICU admission, mechanical ventilation, and death.

Results

A total of 49 patients with a history of LT and COVID-19 infection were identified. Twenty nine patients (59%) were male, the median time from LT was 66 months (1, 128) and the median age at COVID-19 infection was 59 years (52, 65). At COVID-19 diagnosis, the median ALT was 37 U/L (21, 41), AST U/L was 34 (20, 37), ALP U/L was 156 (88, 156), Total Bilirubin was 11 umol/L (7, 14), and INR was 1.1 (1.0, 1.1). The majority of patients (92%) were on tacrolimus monotherapy or a combination of tacrolimus and mycophenolate mofetil (MMF); median tacrolimus level at COVID-19 diagnosis was 5.3 ug/L (4.0, 8.1). Immunosuppression was modified in 8 (16%) patients post-infection; either the tacrolimus dose was reduced or MMF was held. One patient developed acute cellular rejection which recovered after re-initiation of the prior regimen. Eighteen patients (37%) required hospitalization, 6 (12%) were treated with dexamethasone, and 3 (6%) required ICU admission and mechanical ventilation. Four patients (8%) died due to complications of COVID-19. On univariate analysis, neither age, sex, co-morbidities nor duration post-transplant were associated with risk of hospitalization.

Conclusions

In our national retrospective study, approximately 40% of patients required hospitalization with a mortality rate of &lt; 10%. Previous studies have shown proximity to LT as an independent factor for mortality with COVID-19; the median time from LT for our patients was 5 years, which may explain the lower mortality rate. Of note, the median tacrolimus levels were much lower in comparison to the target of 8–10 ug/L used in the first year post-transplant. As the landscape of COVID-19 changes with vaccination, evolving treatments, and increasing rates of variant transmission, additional studies are required to continue identifying trends in clinical outcomes.

Funding Agencies

None

A217 TREATMENT ADHERENCE OF CHRONIC HEPATITIS B PATIENTS WITH HEPATOCELLULAR CARCINOMA FROM THE CANHEPB NETWORK

Background

Chronic hepatitis B (CHB) is the most common cause of hepatocellular carcinoma (HCC) worldwide.

Aims

The primary aim of this study is to explore the degree of treatment adherence to the American Association For The Study of Liver Disease (AASLD) HCC treatment guidelines for patients with CHB-HCC.

Methods

This is a retrospective, cross-sectional study of available data (2005–2020) in patients mono-infected with CHB collected from the Canadian HBV Network; a national consortium across 8 Canadian provinces. We analyzed data using descriptive statistics along with parametric and nonparametric statistical methods with a significance level of p < 0.05.

Results

Of the 6500 patients, 132 (2.0%) patients met inclusion criteria. The median age was 64 (IQR: 53.5- 71.5) with 101 (76%) being male. The median ALT was 40 (IQR: 26–59.5) and the median tumor number was 1(IQR: 1- 2) with a median tumor size of 2.6 cm (IQR: 1.9- 4.5). 98 (74.5%) patients were HBeAg negative with a median viral load of 3.8 logs (IQR 1.9 – 5.8). 58 (43%) patients had cirrhosis at diagnosis. 36% of patients were diagnosed with HCC on their first screening imaging whereas 39% were found to have HCC on repeated surveillance imaging. 116 (87.9%) were on treatment at the time of diagnosis or after (70 (60.3%) NA and 46 (39%) Combination therapy with double NA or NA plus interferon). Out of the 132 patients, BCLC stage 0, A, B, and C represented 30 (23%), 42 (32%), 17 (13%), and 5 (4%) patients, respectively, with 38 (28%) patients with unknown BCLC stage. The overall adherence to AASLD guidelines was 61%. The HCC treatment adherence rate for patients with BCLC stage 0, A, B were 63%, 97.5%, and 23.5%, respectively. BCLC stages C and D did not have a sufficient sample size for analysis. The adherence rate ranged from 53% (Eastern Canada) to 71% (Western Canada) across Canada.

Conclusions

In this retrospective nationwide cohort study of patients with CHB-related HCC, the overall treatment adherence rate to AASLD guidelines was low with notable regional differences. Further analysis will determine the cause of regional differences.

Funding Agencies

None

A110 FEASIBILITY OF EUS-GUIDED PORTAL PRESSURE GRADIENT MEASUREMENT WITHOUT DEEP SEDATION: A PATH TO ACCURATE PORTAL PRESSURE DETERMINATION

Aims

Hepatic venous pressure gradient (HVPG) is the gold standard for the diagnosis and staging of portal hypertension. Previous studies have shown that it underestimates pre-sinusoidal portal hypertension. Endoscopic ultrasound-guided portal pressure gradient (EUS-PPG) can safely measure direct portal vein pressure (PVP) and bridge this diagnostic gap. However, EUS-PPG has so far been performed with patients under deep sedation which can alter HVPG measurement and lead to misclassification of portal hypertension. Ketamine, a conscious sedation agent, has minimal effect on portal hemodynamics. We present our center’s experience with EUS-PPG under ketamine and low dose midazolam.

Methods

We retrospectively reviewed consecutive patients undergoing EUS-PPG with conscious sedation using ketamine and low-dose midazolam (<0.02 mg/kg) at the McGill University Health Centre from February to May 2021. Patients were placed in the left lateral position. Hepatic vein and portal vein were located through EUS via a trans-gastric/hepatic approach. A through the scope 25-gauge needle attached to a manometer was advanced through the liver to measure hepatic vein pressure (HVP) and portal vein pressure (PVP). Three measurements were sampled per vessel and mean pressure differences calculated to obtain PPG. PPG was considered reliable if the differences between the values was no more than 1mmHg.

Results

Three patients underwent EUS-PPG for evaluation of pre-sinusoidal portal hypertension. Cirrhosis was excluded in all patients based on recent liver biopsy or transient elastography. The first patient is a 69-year-old man with splenomegaly and recanalization of the paraumbilical vein on imaging. He received 80 mg of ketamine and no midazolam. HVPG measured was 1 mmHg. EUS-PPG was successful with PPG of 6 mmHg (HVP= 7 mmHg, and PVP= 13 mmHg). The second patient is a 42-year-old woman with previous sleeve gastrectomy and known with portal cavernoma. She received 120 mg of ketamine and 1 mg of midazolam. EUS-PPG was technically difficult due to respiratory movements. The measurement was not considered reliable as differences in PPG were as high as 2mmHg. In this case, PPG was 0mmHg (HVP= 15mmHg, and PVP= 15mmHg). The third patient, a 74-year-old man with hepatic steatosis and splenomegaly received 70 mg of ketamine and 1 mg of midazolam. EUS-PPG was successful (HVP= 3mmHg, PVP= 3mmHg) yielding a PPG 0mmHg. All patients tolerated the procedure well with no procedural or sedation-related complications

Conclusions

Our early experience suggests that EUS-PPG can be successfully and safely performed in patients under conscious sedation with ketamine and low-dose midazolam. This combination may avoid deep sedation with high dose midazolam or propofol which are known to alter accuracy of HVPG.

Measurement of HVP (left) and PVP (right)

Funding Agencies

None

665 Management of Epistaxis Patients After Nasal Pack Removal - Quality Improvement Project

Introduction

Epistaxis is a common emergency and treatments include cautery and nasal packing. NICE guidelines recommend Naseptin® (chlorhexidine and neomycin) and routine practice is to perform cautery if bleeding point identified following pack removal.

Method

Retrospective analysis of electronic records over a 9-month period identified 114 patients admitted with epistaxis.

Results

Demographics: 65 male, 49 females (roughly 13:10 ratio), an average age of 72.5 and median age: 76. 8 patients had 2 presentations with epistaxis (3 had SPA ligation on repeat admission). 97 patients were packed, 17 no packing performed. Reasons for admission without packing was observation after cautery (7), observation without cautery (5) and admission under medics for non-epistaxis issue (5). Of patients with discharge summaries, 90% had naseptin prescribed. Of patient admitted under medics, only 60% discharged with naseptin. 70 patients (61.4%) were cauterized, 16 patients (14%) examined, but no cautery required, and 28 patients (24.5%) had no documentation of examination or cautery attempt.

Conclusions

The majority of patients are receiving naseptin on discharge but room for improvement. Although small sample size of 5, greater portion medical patients discharged without naseptin, better handover required. Almost a quarter of patients (24.5%) did not have any documentation of cautery attempts.

A72 NON-INVASIVE PREDICTION OF ESOPHAGEAL VARICES BY TRANSIENT ELASTOGRAPHY AND PLATELET COUNT IN PATIENTS WITH HEPATITIS B AND ADVANCED CHRONIC LIVER DISEASE: VALIDATION OF BAVENO VI AND EXPANDED BAVENO VI CRITERIA

Background

Patients with compensated advanced chronic liver disease (cACLD) are at higher risk of developing complications from portal hypertension, including esophageal varices (EV). Baveno VI and expanded Baveno VI criteria, based on liver stiffness measurement (LSM) by transient elastography combined with platelet count, have been proposed to avoid unnecessary esophagogastroduodenoscopy (EGD) screening for large esophageal varices needing treatment (EVNT). This approach has not been validated in patients with chronic hepatitis B virus (HBV) infection, who have etiology-specific cut-off of LSM for liver fibrosis.

Aims

We aimed to validate the Baveno VI and expanded Baveno VI criteria for EVNT in HBV patients with cACLD.

Methods

We performed a retrospective analysis of HBV patients who underwent LSM in 2014–2020. Inclusion criteria were: a) diagnosis of cACLD, defined as LSM &gt;9 kPa; b) availability of EGD and platelets within 1 year of LSM. Baveno VI (LSM &lt;20 kPa and platelets &gt;150,000) and expanded Baveno VI criteria (LSM &lt;25 kPa and platelets &gt;110,000) were tested for EGD sparing. Diagnostic performance of these criteria against gold standard (EGD) was computed and compared to patients with hepatitis C virus (HCV) infection and nonalcoholic steatohepatitis (NASH) etiologies, where these criteria have been widely validated. In these patients, the threshold for cACLD definition was &gt;10 kPa.

Results

A total of 287 patients (mean age 56, 95% Child A) were included, comprising of 43 HBV (58% on antiviral therapy), 134 HCV and 110 NASH patients. The prevalence of any grade EV and EVNT was 25% and 8% in the whole cohort, with 19% and 5% in HBV patients, respectively. Table 1 reports diagnostic performance, spared EGD and missed EVNT according to non-invasive criteria and cACLD etiology. Both Baveno VI and expanded Baveno VI criteria performed well in patients with HBV-related cACLD. There was no significant difference on diagnostic performance of these non-invasive criteria across the cACLD etiologies.

Conclusions

These results support use of non-invasive criteria based on LSM and platelets to spare unnecessary EGD in patients with HBV and cACLD. Baveno VI and expanded Baveno VI criteria can improve resource utilization and avoid invasive testing in context of screening EGD for patients with HBV-related cACLD.

Funding Agencies

None

Zinc Gluconate Induces Potentially Cancer Chemopreventive Activity in Barrett's Esophagus: A Phase 1 Pilot Study

BACKGROUND

Chemopreventive effects of zinc for esophageal cancer have been well documented in animal models. This prospective study explores if a similar, potentially chemopreventive action can be seen in Barrett's esophagus (BE) in humans.

AIMS

To determine if molecular evidence can be obtained potentially indicating zinc's chemopreventive action in Barrett's metaplasia.

METHODS

Patients with a prior BE diagnosis were placed on oral zinc gluconate (14 days of 26.4 mg zinc BID) or a sodium gluconate placebo, prior to their surveillance endoscopy procedure. Biopsies of Barrett's mucosa were then obtained for miRNA and mRNA microarrays, or protein analyses.

RESULTS

Zinc-induced mRNA changes were observed for a large number of transcripts. These included downregulation of transcripts encoding proinflammatory proteins (IL32, IL1β, IL15, IL7R, IL2R, IL15R, IL3R), upregulation of anti-inflammatory mediators (IL1RA), downregulation of transcripts mediating epithelial-to-mesenchymal transition (EMT) (LIF, MYB, LYN, MTA1, SRC, SNAIL1, and TWIST1), and upregulation of transcripts that oppose EMT (BMP7, MTSS1, TRIB3, GRHL1). miRNA arrays showed significant upregulation of seven miRs with tumor suppressor activity (-125b-5P, -132-3P, -548z, -551a, -504, -518, and -34a-5P). Of proteins analyzed by Western blot, increased expression of the pro-apoptotic protein, BAX, and the tight junctional protein, CLAUDIN-7, along with decreased expression of BCL-2 and VEGF-R2 were noteworthy.

CONCLUSIONS

When these mRNA, miRNA, and protein molecular data are considered collectively, a cancer chemopreventive action by zinc in Barrett's metaplasia may be possible for this precancerous esophageal tissue. These results and the extensive prior animal model studies argue for a future prospective clinical trial for this safe, easily-administered, and inexpensive micronutrient, that could determine if a chemopreventive action truly exists.

Non-invasive mid-term ECG monitoring for the detection of atrial fibrillation in an outpatient population

Background

Atrial fibrillation (AF) is a common arrhythmia with significant morbidity due to an increased risk of ischemic stroke. Outpatient electrocardiogram (ECG) monitoring is an integral part of the diagnosis of AF. Conventional 24 hour Holter monitoring can be cumbersome and often fails to diagnose patients with paroxysmal AF. Spyder ECG is a non-invasive ECG monitoring device that allows wireless transmission of ECG information for analysis. It is small and comfortable, allowing for easy application for the screening and detection of AF over a mid-term duration.

Purpose

This study aims to evaluate the incidence of AF in patients with no prior AF and CHADsVASC score of at least 1 with the use of the Spyder ECG mid-term ECG monitoring device.

Methods

Patients aged 21 to 85 years old with no prior history of AF and CHADsVASC score of at least 1 were recruited from outpatient clinics of 3 large tertiary hospitals in Singapore from December 2016 to April 2019. Patients wore the Spyder ECG device for up to 2 weeks, during which continuous ECG information was uploaded onto a central cloud database and analysed.

Results

There were 363 patients recruited. The mean age was 61±10.0 years and 65.1% were male. There were 80.3% Chinese, 11.6% Malay, 7.5% Indian and 20.6% of other races. 68.3% of the patients were non-smokers and 74.0% of them were non-alcohol drinkers. The mean BMI of 25.5±4.7 kg/m2. The patient population had significant co-morbidities. 76.3% of the patients had hypertension, 69.4% of them had hyperlipidemia and 40.5% of them had diabetes mellitus. 10.0% of them had congestive cardiac failure and 56.7% had ischaemic heart disease. 11.3% of patients had a previous stroke and 20.4% had a prior myocardial infarction. 7.8% of the patients had asthma, 5.8% of them had thyroid disease and 9.9% of them had chronic kidney disease. They were monitored for a mean of 5.4±2.9 days each. There were 15 (4.1%) patients in whom AF was detected. The patients with AF wore the device for a mean of 5.7±2.0 SD days. The mean burden of AF was 9.0% of monitored time. 46.7% of the patients with AF had detection of AF on the first day, 26.7% on the second day, 13.3% on the third day and 13.3% on the seventh day. The mean duration of the first episode of AF was 251±325 minutes. 7 out of 15 (46.7%) of patients had first episodes of AF lasting less than 10 minutes.

Conclusion

Continuous mid-term ECG monitoring was able to detect AF in 15 (4.1%) of a population of 363 patients with no prior AF and CHADsVASC score of at least one, monitored for a mean of 5.4 days. Most episodes (53.3%) of AF were detected after the first day of ECG monitoring.

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): Duke-NUS Medical School Singapore

Identification of the intermittent nature of trace mitral and/or aortic regurgitation: long-term longitudinal echocardiogram study in children with Dravet syndrome treated with fenfluramine

Background

Previous studies have identified the presence of trace valvular regurgitation; however, these studies are typically cross-sectional assessments at a single point in time and provide no information regarding the natural history of trace aortic or mitral regurgitation (AR, MR). To our knowledge no study has assessed valve function in growing children with longitudinal echocardiogram (ECHO) assessments.

Purpose

To monitor cardiac valve function with regular, standardized ECHOs in patients with Dravet syndrome (DS) treated with fenfluramine for up to 3 years.

Methods

Patients with DS who completed either of two double-blind Phase 3 clinical trials were eligible to enroll in the open label extension (OLE) study. Patients were to be excluded from entry into the double-blind trials if they exhibited any degree of AR or MR, including trace; or pulmonary artery hypertension (PAH). However, trace MR or AR were not exclusion criteria for continuation into the OLE study. All patients had an ECHO prior to initiation of treatment in the double-blind study, after 6 to 8 weeks of treatment, and at the end of that study. In the OLE study, ECHOs were performed at study week 4, 5, or 6, and every 3 months thereafter. Valve morphology was also examined.

Results

As of September 1, 2019 a total of 330 patients had enrolled in the OLE study and received at least one dose of fenfluramine. The average age of patients at enrollment was 9.0±4.6 years, 27.6% were &lt;6 years old, and 54.5% were male. The median duration of treatment with fenfluramine in the OLE study was 631 days (min, max; 7, 1086 days), and a total of 2,691 ECHOs had been performed. The point prevalence of trace MR was 10.6% at OLE study entry and ranged from 2.8% to 12.9% thereafter. All instances of trace MR were transient events that reverted to absent or oscillated between trace and absent at later study visits. Four patients demonstrated trace AR at one or more visits and all had reverted to absent at their most recent examination. No changes in valve morphology were observed.

Conclusions

In this long-term longitudinal ECHO study in DS children treated with fenfluramine, we identified that trace MR and AR were intermittent and not predictive of future valve disease. In all cases trace reverted to absent regurgitation at subsequent ECHOs. No valve morphological changes were seen. The intermittent and transient nature of trace regurgitation observed in this study is consistent with current ECHO guidelines, which consider trace regurgitation to be a normal physiologic phenomenon.

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Zogenix, Inc.

Favorable therapeutic index of an orally-active small-molecule antagonist of the platelet protease-activated receptor-4, BMS-986141, compared with the P2Y12 antagonist ticagrelor in cynomolgus monkeys

Introduction

BMS-986141 is an orally-active small-molecule platelet thrombin receptor antagonist selective for the protease-activated receptor-4 (PAR4), a human platelet thrombin receptor.

Purpose

This study assessed effects of BMS-986141 vs. the P2Y12 antagonist ticagrelor, a standard of care antiplatelet agent, on arterial thrombosis (AT), mesenteric bleeding time (MBT) and platelet aggregation in monkeys.

Methods

Studies were conducted in models of electrically-mediated carotid artery thrombosis and MBT in anesthetized monkeys. Monkeys were given a single oral dose of BMS-986141 (0.05, 0.1, 0.5 mg/kg) or vehicle (n=8/group). At 2 hr post-dose, in vivo AT, MBT as well as ex vivo platelet aggregation were monitored in the same animal. Ticagrelor was studied as a comparator and given as IV bolus plus infusion at 0.0023+0.017 to 0.075+0.6 (mg/kg+mg/kg/h) (n=5–6/group). Thrombus weight reduction, MBT increase over vehicle, and platelet aggregation inhibition were determined. Peak platelet aggregation responses to activation peptides selective for PAR4 (PAR4-AP, 12.5 μM) and PAR1 (PAR1-AP, 18 μM), to collagen (5 μg/ml) and to ADP (20 μM) were determined by whole blood aggregometry.

Results

BMS-986141 inhibited platelet aggregation induced by PAR4-AP in human and monkey blood in vitro with comparable IC50 of 1.8±0.3 and 1.2±0.3 nM, respectively. BMS-986141 at 0.5 mg/kg completely inhibited platelet aggregation induced by PAR4-AP but not PAR1-AP, ADP and collagen, suggesting PAR4 receptor selectivity. In the AT model, BMS-986141 at 0.05, 0.1 and 0.5 mg/kg reduced thrombus weight by 36±7*, 63±8*, and 88±3%*, respectively (*P&lt;0.05 vs. vehicle). BMS-986141 increased MBT by up to 1.2-fold. In a separate study, ticagrelor at 0.0023+0.017, 0.0068+0.055, 0.0255+0.18 and 0.075+0.6 (mg/kg+mg/kg/h IV) reduced thrombus weight by 19±8, 36±5*, 76±6* and 89±1%*, and increased MBT by respectively by 1.7-, 6.4-*, &gt;10-*, and &gt;10-fold*, respectively (*P&lt;0.05 vs. vehicle).

Conclusion

Comparable antithrombotic efficacy was observed between BMS-986141 and ticagrelor in monkeys. BMS-986141 exhibited lower MBT compared with ticagrelor at equivalent antithrombotic doses. This study suggests that PAR4 antagonism provides a potentially safer antiplatelet therapy.

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Research was supported by Bristol-Myers Squibb

Prevalence of hypoxia and correlation with glycolytic metabolism and angiogenic biomarkers in metastatic colorectal carcinoma

PURPOSE

Hypoxia is associated with aggressive tumour behaviour and can influence response to systemic therapy and radiotherapy. The prevalence of hypoxia in metastatic colorectal cancer is poorly understood, and the relationship of hypoxia to patient outcomes has not been clearly established. The aims of the study were to evaluate hypoxia in metastatic colorectal cancer with [¹⁸F]Fluoromisonidazole ([¹⁸F]FMISO PET) and correlate these findings with glycolytic metabolism ([¹⁸F]FDG PET) and angiogenic blood biomarkers and patient outcomes.

METHODS

Patients with metastatic colorectal cancer received routine staging investigations and both [¹⁸F] FMISO PET and [¹⁸F] FDG PET scans. Correlative blood specimens were also obtained at the time of the [¹⁸F] FMISO PET scan. Patient follow-up was performed to establish progression-free survival.

RESULTS

A total of 40 patients were recruited into the trial. [¹⁸F]FMISO and [¹⁸F]FDG PET scans showed a significant correlation of SUV_max (p = 0.003). A significant correlation of progression-free survival and [¹⁸F] FMISO TNR (p = 0.02) and overall survival with [¹⁸F]FMISO TNR (p = 0.003) and [¹⁸F]FDG TGV (p = 0.02) was observed. Serum levels of osteopontin, but not VEGF, correlated with [¹⁸F] FMISO and [¹⁸F]FDG PET scan parameters.

CONCLUSION

[¹⁸F]FMISO PET uptake in metastatic colorectal cancer significantly correlates with glycolytic metabolism and is predictive of progression-free and overall survival. These findings have implications for the assessment and treatment of metastatic colorectal cancer patients with novel therapies which affect tumour angiogenesis and hypoxia.

FRI0354 FACTORS AFFECTING SELF-REPORTED PHYSICAL CTIVITY IN PATIENTS WITH PSORIATIC ARTHRITIS

Background:

Despite the known benefits of exercise1, patients with osteoarthritis (OA) and rheumatoid arthritis (RA) are reported to have low levels of physical activity2. Exercise participation is not well studied in psoriatic arthritis (PsA) cohorts. This study aims to explore which factors predict exercise participation across cohorts and specifically in the PsA cohort.

Objectives:

The primary aim of this study was to determine which clinical factors were predictive of self- reported physical activity levels in patients with PsA. A secondary aim was to explore differences in self-reported physical activity levels amongst patients with PsA, OA and RA.

Methods:

Patients with the diagnosis of PsA, RA or OA are recruited prospectively at two tertiary hospital rheumatology clinics over 12 months. Demographic data is captured by the multi-dimensional health assessment questionnaire, the international physical activity questionnaire short form captures self-reported physical activity and self-efficacy for exercise (SEE) is assessed using the SEE scale. Clinical data including joint count, body mass index and co-morbidities including fibromyalgia are collected for all patients, in addition to PsA specific data including skin and enthesitis indices.

Results:

205 patients (PsA n=62, RA n=83, OA n=60) were recruited across two sites. There was no significant difference in self-reported physical activity between OA, RA and PsA cohorts. Fibromyalgia was present in 30% of each cohort. In patients with PsA, univariate analysis showed that co-existent fibromyalgia, age and self-efficacy for exercise were predictors of physical activity levels. Skin disease and enthesitis were not predictors of physical activity in the PsA cohort.

Table 1.

Univariate Analyses of effect of Clinical Features on Physical Activity levels in PsA

Non-exercisers versus ExercisersOR (95% CI)P-valueLEI1.35 (0.92-1.97)0.127PASI0.8 (0.6-1.07)0.133DLQI1.03 (0.92-1.16)0.589BMI0.97 (0.91-1.04)0.415DAS280.79 (0.55-1.14)0.205Concurrent Fibromyalgia4.46 (1.37-14.49)0.012Age1.05 (1.00-1.10)0.013Self-efficacy for exercise0.97 (0.95-0.99)0.019Pain1.17 (0.99-1.37)0.061Function1.3 (1.02-1.65)0.031Patient global1.14 (0.96-1.34)0.128Depression0.97 (0.51-1.84)0.930Table 2.

Multivariable Analysis on Physical Activity in PsA

Non-exercisers vs ExercisersOR (95% CI)P-valueConcurrent fibromyalgia5.1 (1.44-18.08)0.0117Age1.05 (1.00-1.11)0.0342

Conclusion:

In the PsA cohort, fibromyalgia and age were associated with lower levels of physical activity. DLQI, PASI, LEI did not predict physical activity in PsA. Multivariate analysis showed higher pain levels and lower self-efficacy scores were associated with lower physical activity across arthritis groups.

References:

[1]Der Ananian C, Wilcox S, Watkins K, Saunders RP, Evans AE. (2008). Factors Associated with Exercise Participation in Adults with Arthritis.Journal of Aging and Physical Activity, 16: 125-143

[2]Wilcox S, Der Ananian C, Abbott J, Vrazel J, Ramsey C, Sharpe PA, Brady T. (2006). Perceived Exercise Barriers, Enablers, and Benefits Among Exercising and Nonexercising Adults With Arthritis: Results from a Qualitative Study.Arthritis & Rheumatism, 55(4): 616-627

Acknowledgments:

Joseph Descallar

Dana Georgevsky

Dr Michael Oliffe

Dr Diana Chessman

Department of Rheumatology, Liverpool Hospital NSW Australia

Department of Rheumatology, Westmead Hospital NSW Australia

Disclosure of Interests:

None declared

Comparison of bone structure and microstructure in the metacarpal heads between patients with psoriatic arthritis and healthy controls: an HR-pQCT study

Human cadaveric study has indicated that the metacarpal head (MCH) is intracapsular in location. We hypothesized that exposure to the intra-articular inflammatory milieu in psoriatic arthritis (PsA) will lead to bone loss in the MCH.

INTRODUCTION

To compare the bone structure and microstructure in the MCH between patients with PsA and healthy controls by high-resolution peripheral quantitative CT (HR-pQCT), and to ascertain factors associated with bone loss in PsA patients.

METHODS

Sixty-two PsA patients without joint destruction and 62 age-, gender-, and body mass index-matched healthy subjects underwent HR-pQCT imaging of the second and third MCH (MCH 2&3). The number and volume of bone erosion and enthesiophytes, as well as volumetric bone mineral density (vBMD) and microstructure at the MCH 2&3, were recorded. Correlation analysis and multivariable linear regression models were used to determine the association of demographic and disease-specific variables with compromised bone structure and microstructure in PsA.

RESULTS

At the MCH 2&3, bone erosion (p = 0.003) and enthesiophyte (p = 0.000) volumes in PsA patients were significantly larger than healthy controls. In PsA patients, older age was associated with a larger erosion and enthesiophyte volume. Concerning the mean vBMD and microstructure at the MCH 2&3, PsA patients had significantly lower mean vBMD (average vBMD - 6.9%, trabecular vBMD - 8.8%, peri-trabecular vBMD - 7.7%, meta-trabecular vBMD - 9.8%), trabecular bone volume fraction (- 8.8%), and trabecular thickness (- 8.1%) compared with control subjects. Multivariable regression analysis revealed that older age and a higher C-reactive protein level were associated with trabecular bone loss.

CONCLUSIONS

PsA patients had a higher burden of bone damages (erosions and enthesiophytes) and trabecular bone loss compared with healthy control at the MCH. Inflammation contributed to the deterioration in trabecular microstructure in these patients.

Phlebotomy resulting in controlled hypovolaemia to prevent blood loss in major hepatic resections (PRICE-1): a pilot randomized clinical trial for feasibility

BACKGROUND

Major liver resection is associated with blood loss and transfusion. Observational data suggest that hypovolaemic phlebotomy can reduce these risks. This feasibility RCT compared hypovolaemic phlebotomy with the standard of care, to inform a future multicentre trial.

METHODS

Patients undergoing major liver resections were enrolled between June 2016 and January 2018. Randomization was done during surgery and the surgeons were blinded to the group allocation. For hypovolaemic phlebotomy, 7-10 ml per kg whole blood was removed, without intravenous fluid replacement. Co-primary outcomes were feasibility and estimated blood loss (EBL).

RESULTS

A total of 62 patients were randomized to hypovolaemic phlebotomy (31) or standard care (31), at a rate of 3·1 patients per month, thus meeting the co-primary feasibility endpoint. The median EBL difference was -111 ml (P = 0·456). Among patients at high risk of transfusion, the median EBL difference was -448 ml (P = 0·069). Secondary feasibility endpoints were met: enrolment, blinding and target phlebotomy (mean(s.d.) 7·6(1·9) ml per kg). Blinded surgeons perceived that parenchymal resection was easier with hypovolaemic phlebotomy than standard care (16 of 31 versus 10 of 31 respectively), and guessed that hypovolaemic phlebotomy was being used with an accuracy of 65 per cent (20 of 31). There was no significant difference in overall complications (10 of 31 versus 15 of 31 patients), major complications or transfusion. Among those at high risk, transfusion was required in two of 15 versus three of nine patients (P = 0·326).

CONCLUSION

Endpoints were met successfully, but no difference in EBL was found in this feasibility study. A multicentre trial (PRICE-2) powered to identify a difference in perioperative blood transfusion is justified. Registration number: NCT02548910 ( http://www.clinicaltrials.gov).

Rescue supraglottic airway devices at caesarean delivery: What are the options to consider?

Tracheal intubation is considered the gold standard means of securing the airway in obstetric general anaesthesia because of the increased risk of aspiration. Obstetric failed intubation is relatively rare. Difficult airway guidelines recommend the use of a supraglottic airway device to maintain the airway and to allow rescue ventilation. Failed intubation is associated with a further increased risk of aspiration, therefore there is an argument for performing supraglottic airway-guided flexible bronchoscopic intubation (SAGFBI). The technique of SAGFBI has a high success rate in the non-obstetric population, it protects the airway and it minimises task fixation on repeated attempts at laryngoscopic tracheal intubation. However, after failed intubation via laryngoscopy, there is a lack of specific recommendations or indications for SAGFBI in current obstetric difficult airway guidelines in relation to achieving tracheal intubation. Our narrative review explores the issues pertaining to airway management in these cases: the use of supraglottic airway devices and the techniques of, and technical issues related to, SAGFBI. We also discuss the factors involved in the decision-making process as to whether to proceed with surgery with the airway maintained only with a supraglottic airway device, or to proceed only after SAGFBI.

Major liver surgery in a Jehovah’s Witness patient: challenges for safe surgery

Jehovah’s Witnesses presenting for major surgery run the risk of major bleeding, which is complicated by the refusal to accept blood transfusion. We present a case of a 63-year-old woman, a Jehovah’s Witness, who was diagnosed with hepatocellular carcinoma and advised for curative laparoscopic liver segmentectomy. Due to the risk of significant intraoperative haemorrhage, her perioperative care was coordinated in a multidisciplinary manner. Informed consent requires the physician to advise on the material risks of undertaking major surgery without blood transfusion and the possible alternatives. Conflicting ethical issues of patient autonomy and beneficence related to refusal of blood products also arise. Perioperative strategies to minimise blood loss, maximise haematopoiesis and tolerance of anaemia to facilitate safe surgery in such patients are also presented. Written patient consent obtained.

Trabecular bone score in adults with cerebral palsy

CONTEXT

Bone fragility in cerebral palsy (CP) is secondary to a complex interplay of functional, hormonal, and nutritional factors that affect bone remodelling. A greater understanding of bone microarchitectural changes seen in CP should assist therapeutic decision making.

OBJECTIVE

To examine the relationship between trabecular bone score (TBS), BMD and fractures in adults with CP; the influence of clinical factors and body composition on bone microarchitecture were explored.

DESIGN

Retrospective cross-sectional study.

SETTING AND PARTICIPANTS

43 adults (25 male) with CP of median age 25 years (interquartile range 21.4-33.9) who had evaluable dual-energy X-ray absorptiometry imaging of the lumbar spine from a single tertiary hospital between 2005-March 2018.

RESULTS

24/43 (55.8%) of patients had TBS values indicating intermediate or high risk of fracture (<1.31). TBS correlated with areal BMD at the lumbar spine, femoral neck and total body. TBS was significantly associated with arm and leg lean mass, with adjustment for age, gender and height (adjusted R² = 0.18, p = 0.042 for arm lean mass; adjusted R² = 0.19, p = 0.036 for leg lean mass). There was no difference in TBS when patients were grouped by fracture status, anticonvulsant use, gonadal status or use of PEG feeding. TBS was lower in non-ambulatory patients compared with ambulatory patients (1.28 vs 1.37, p = 0.019).

CONCLUSIONS

Abnormal bone microarchitecture, as measured by TBS, was seen in >50% of young adults with CP. TBS correlated with both areal BMD and appendicular lean mass. Maintaining muscle function is likely to be important for bone health in young adults with CP and needs to be confirmed in further studies.

Dynamics of the Phanerochaete carnosa transcriptome during growth on aspen and spruce

BACKGROUND

The basidiomycete Phanerochaete carnosa is a white-rot species that has been mainly isolated from coniferous softwood. Given the particular recalcitrance of softwoods to bioconversion, we conducted a comparative transcriptomic analysis of P. carnosa following growth on wood powder from one softwood (spruce; Picea glauca) and one hardwood (aspen; Populus tremuloides). P. carnosa was grown on each substrate for over one month, and mycelia were harvested at five time points for total RNA sequencing. Residual wood powder was also analyzed for total sugar and lignin composition.

RESULTS

Following a slightly longer lag phase of growth on spruce, radial expansion of the P. carnosa colony was similar on spruce and aspen. Consistent with this observation, the pattern of gene expression by P. carnosa on each substrate converged following the initial adaptation. On both substrates, highest transcript abundances were attributed to genes predicted to encode manganese peroxidases (MnP), along with auxiliary activities from carbohydrate-active enzyme (CAZy) families AA3 and AA5. In addition, a lytic polysaccharide monooxygenase from family AA9 was steadily expressed throughout growth on both substrates. P450 sequences from clans CPY52 and CYP64 accounted for 50% or more of the most highly expressed P450s, which were also the P450 clans that were expanded in the P. carnosa genome relative to other white-rot fungi.

CONCLUSIONS

The inclusion of five growth points and two wood substrates was important to revealing differences in the expression profiles of specific sequences within large glycoside hydrolase families (e.g., GH5 and GH16), and permitted co-expression analyses that identified new targets for study, including non-catalytic proteins and proteins with unknown function.

An explanation of the reversal of erythrocyte echinocytosis by incubation and storage by serum albumin

It is proposed that the specific reversal by serum albumin of the erythrocyte echinocytosis in an inorganic phosphate buffer saline or in a saline, either after 24 h in blood or after a storage of 6-7 weeks in SGAM or PAGGSM media, is due to a cell dehydration by a decrease of the total NaCl and KCl concentrations favoring the stomatocytogenic slow outward transport of inorganic phosphate with a hydrogen ion by band 3 anion exchanger, which was previously proposed to control the erythrocyte shape. This proposal would indicate that the opposition of the erythrocyte echinocytosis by serum albumin is not limited to binding to echinocytogenic amphiphiles, supported by the ability of the band 3-based mechanism of control of the erythrocyte shape to explain a variety of observations on the erythrocyte shape. It would also imply that this mechanism is a determinant of the erythrocyte rheological properties since influenced by cell shape and volume. It is shown that the above process of stomatocytosis can explain stomatocytoses by different agents as well as a knizocytosis induced in vitro and occurring in acquired and inherited disorders and other situations. Lastly, it can also explain the opposition of hemolysis by mannitol in SGAM and PAGGSM media.

A Dynamic Three-Dimensional Air Pollution Exposure Model for Hong Kong

INTRODUCTION

High-density high-rise cities have become a more prominent feature globally. Air quality is a significant public health risk in many of these cities. There is a need to better understand the extent to which vertical variation in air pollution and population mobility in such cities affect exposure and exposure-response relationships in epidemiological studies.

METHODS

We used a novel strategy to execute a staged model development that incorporated horizontal and vertical pollutant dispersion, building infiltration, and population mobility patterns in estimating traffic-related air pollution (TRAP) exposures in the Hong Kong Special Administrative Region (HK SAR).

Two street-level spatial monitoring campaigns were undertaken to facilitate the creation of a two-dimensional land-use regression (LUR) model. A network of approximately 100 passive nitric oxide-nitrogen dioxide (NO-NO2) monitors was deployed for two-week periods during the cool and warm seasons. Sampling locations were selected based on population and road network density with a range of physical and geographical characteristics represented. Eight sets of portable monitors for black carbon (BC) and particulate matter ≤2.5 μm in aerodynamic diameter (PM2.5) were rotated so as to be deployed at 80 locations for a 24-hour period. Land-use, geographical, and emissions layers were combined with the spatial monitoring campaign results to create spatiotemporal exposure models.

Vertical air pollution monitoring was carried out at six strategic locations for two weeks in the warm season and two weeks in the cool season. Continuous measurements were carried out at four different heights of a residential building and on both sides of a street canyon. The heights ranged from as close to street level as practically possible up to a maximum of 50 meters (i.e., below the 20th floor). Paired indoor monitoring was included to allow the calculation of infiltration coefficients to feed into the dynamic component of the exposure model.

The final phase of model development addressed population mobility. A population-representative travel behavior survey (n = 89,358) was used to produce the dynamic component of the model, with time-weighted exposure estimates split between home and work or school. Transport microenvironment exposures were taken from published literature. Time-activity exposure estimates were split by age, sex, and employment status.

Development of the exposure model in distinct packages allowed the application of a staged approach to an existing cohort data set. Mortality risk estimates for an elderly cohort of 66,000 Hong Kong residents were calculated using increasing exposure model complexity.

RESULTS

The street-level (2-dimensional [2D]) LUR modeling captured important spatial parameters and represented spatial patterns of air quality in Hong Kong that were consistent with the literature. Higher concentrations of gaseous pollutants were centered in Kowloon and the northern region of Hong Kong Island. PM2.5 and BC predictions exhibited a north-south/west-east gradient, with higher concentrations in the northwest due to regional transport of particulate pollutants from Mainland China. While the degree of explained variance of the models was in line with other LUR modeling efforts in Asia, R2 values ranged from 0.46 (NO2) to 0.59 (PM2.5).

Exponential decay rates (k) were calculated at each monitoring location. While it was clear that k values were higher during the warm season than the cool season, no robust patterns were identified relating to the canyon physical parameters. Therefore, a single decay rate was used for each pollutant across the whole region for derivation of the 3-dimensional (3D) exposure layer (k = 0.004 and 0.012 for PM2.5 and BC, respectively). An alternative decay profile that capped decay at 20 meters above street level was proposed and evaluated. The electrochemical sensors deployed during the canyon campaigns did not exhibit the degree of interunit precision necessary to detect vertical variations in gaseous pollutants, and these results were excluded from the study.

We found that values of the median infiltration efficiencies (Finf) for both BC and PM2.5 were especially high during the cool season (91%). Finf values were somewhat lower during the warm season (81% and 88% for PM2.5 and BC, respectively), and we found a significant negative correlation between air conditioning use and Finf. The Finf for a mechanically ventilated office building was 45% and 40% during the cool and warm seasons, respectively.

Dynamic exposure estimates were compared against home outdoor estimates. As expected, the addition of an indoor component decreased time-weighted exposure estimates, which were balanced out to some extent by the inclusion of transport microenvironments. Overall, mean time-weighted exposures for the full dynamic model were around 20% lower than home outdoor estimates.

Higher levels of exposures were found with working adults and students than for those neither in work nor study. This was due to the increased mobility of people going to work or school. The exposures to PM2.5, BC, and NO2 were, respectively, 13%, 39%, and 14% higher for people who were under age 18, compared with people who were 65 or older. Exposure estimates for the female population were approximately 4% lower.

The availability of an existing cohort data set of elderly Hong Kong residents (n = 66,820) facilitated the calculation and comparison of mortality risk estimates for the different exposure models.

Overall, results indicated that the application of exposure estimates that incorporated infiltration, vertical, and to a lesser extent, dynamic components resulted in higher hazard ratios (HRs) than the standard street-level model and increased the number of significant associations with all-natural-cause, cardiovascular, and respiratory mortality outcomes.

CONCLUSIONS

The results from the study provided the first evidence that considering air pollution exposure in a dynamic 3D landscape would benefit epidemiological studies. Higher HRs and a greater number of significant associations were found between mortality and pollutant exposures that would not have been found had standard 2D exposure models been used. Dynamic models can also identify differential exposures between population subtypes (e.g., students and working adults; those neither in work nor study).

Improved urban building design appears to be stimulating the dispersion of local TRAP in street canyons. Conversely, Finf values found in naturally ventilated buildings were high, and residences provided little protection from ambient air pollution.

We have demonstrated that the creation of effective advanced exposure models is possible in Asian cities without an undue burden on resources. We recommend that vertical exposure patterns be incorporated in future epidemiological studies in high-rise cities where the floor of residence is recorded in health record data.

Stenosis detection and quantification on cardiac CTCA using panoramic MIP of coronary arteries

In this work, we proposed to demonstrate the entire 3D coronary tree using panoramic maximum intensity projection (MIP) of coronary arteries, and to detect and quantify coronary stenosis from computed tomography coronary angiography (CTCA). The performance of the proposed method was assessed in comparison with invasive coronary angiography (ICA) as reference standard. Six anonymized CTCA datasets were tested. MIP method achieved a sensitivity of 82% and a specificity of 95% for the stenosis detection with a good reproducibility (i.e. Cohen's kappa coefficient of 0.74 for the intra-rater agreement, and 0.45 for the inter-raters agreement). In stenosis quantification, three image options are provided. The original density images resulted in an accuracy of 0.85. The edge map images resulted in an accuracy of 0.79. The image combination had a better accuracy of 0.89 than any single image option. In conclusion, the panoramic MIP provided fast and accurate way for the stenosis detection and quantification. It may be helpful to assist the radiologist in identifying the location of the greatest narrowing in clinical practice.

Fractures in spina bifida from childhood to young adulthood

This study assessed the prevalence and types of fractures in spina bifida and examined risk factors for fracture. Fracture prevalence was highest in childhood and reduced in adolescence and young adulthood. The importance of maintaining mobility is highlighted by the increased risk of fracture in those who are non-ambulatory.

INTRODUCTION

The aims of this study are to study the prevalence and types of fractures according to age group in spina bifida and examine risk factors associated with fracture.

METHODS

This is a retrospective cohort study of 146 individuals with spina bifida aged 2 years or older who attended the paediatric or adult spina bifida multidisciplinary clinic at a single tertiary hospital.

RESULTS

Median age at which first fracture occurred was 7 years (interquartile range 4-13 years). Fracture rates in children (ages 2-10), adolescents (ages 11-18) and adults (age > 18) were 10.9/1000 (95 % confidence interval 5.9-18.3), 5.4/1000 (95 % CI 1.5-13.8) and 2.9/1000 (95 % CI 0.6-8.1) patient years respectively. Childhood fractures predominantly involved the distal femur and femoral shaft; these fractures were rarely seen in adulthood. Non-ambulatory status was associated with a 9.8 times higher risk of fracture compared with ambulatory patients (odds ratio 9.8, p = 0.016, 95 % CI 1.5-63.0). Relative risk of re-fracture was 3.1 (95 % CI 1.4-6.8). Urological intervention with intestinal segments was associated with renal calculi (p = 0.037) but neither was associated with fracture.

CONCLUSIONS

The risk of fracture is lower in adults compared with children with spina bifida. The predominant childhood fracture affects the distal femur, and immobility is the most significant risk factor for fracture. Clinical factors contributing to fracture risk need to be elucidated to enable selection of patients who require investigation and treatment of osteoporosis.

Acute photosensitisation and mortality in a herd of dairy cattle in Tasmania

CASE HISTORY

A herd of Holstein, Jersey, or Holstein-Jersey cross lactating cattle of mixed ages presented with a sudden drop in milk yield in 94/678 cows on 3 October 2014 (Day 0). The herd was located in Gretna in the Derwent Valley (Tasmania, Australia) and had been grazing dryland pasture.

CLINICAL FINDINGS

On Day 0 the cows variably showed recumbency, peracute photosensitisation, inflamed coronary bands, conjunctival erythema, periauricular oedema, distress indicated by kicking at the flank, bruxism, discomfort, weight shifting, vocalisation indicating pain and depression. Blood samples collected on Day 4 from five clinically affected cows showed high activities of aspartate aminotransferase, glutamate dehydrogenase and gamma-glutamyl transferase. Morbidity, based on the number of treated cases within 72 hours of clinical onset, was estimated at 165/678 cows (24.3%). Mortality over the first 30 days was 19/678 cows (2.8%).

PATHOLOGICAL FINDINGS

Necropsies of two cows on Day 4 showed marked distension of the gall bladder and extensive icterus. Necropsies of another two cows on Day 5 showed enlarged livers with severe damage and oedema of the distal abomasum. Severe ulcerative abomasal gastritis was present in both cows. Hepatic histopathology was consistent with chronic cholangiohepatitis.

MYCOTOXICOLOGY

Fifty-five different mycotoxins were detected from a barley grass (Hordeum murinum) sample from the presumably contaminated pasture. Concentrations of B-trichothecenes, fumonisins, and zearalenone metabolites from this sample were remarkably high. The leaf smut, Jamesdicksonia dactylidis, that has not been previously reported in Tasmania, was identified from the sample of barley grass, but it is not known whether the smut can produce toxins.

DIAGNOSIS

Probably an undescribed peracute mycotoxicosis associated with the ingestion of contaminated dryland pasture.

CLINICAL RELEVANCE

A definitive diagnosis could not be reached in this case of acute photosensitisation and mortality in dairy cattle grazing possibly contaminated dryland pasture. The findings differed from both facial eczema and acute bovine liver disease, suggesting an undescribed mycotoxicosis.