Single Australian Centre Research Articles

Clinical Snapshot of Group A Streptococcal Isolates from an Australian Tertiary Hospital

Streptococcus pyogenes (Group A Streptococcus, GAS) is a human-restricted pathogen that causes a wide range of diseases from pharyngitis and scarlet fever to more severe, invasive infections such as necrotising fasciitis and streptococcal toxic shock syndrome. There has been a global increase in both scarlet fever and invasive infections during the COVID-19 post-pandemic period. The aim of this study was the molecular characterisation of 17 invasive and non-invasive clinical non-emm1 GAS isolates from an Australian tertiary hospital collected between 2021 and 2022. Whole genome sequencing revealed a total of nine different GAS emm types with the most prevalent being emm22, emm12 and emm3 (each 3/17, 18%). Most isolates (14/17, 82%) carried at least one superantigen gene associated with contemporary scarlet fever outbreaks, and the carriage of these toxin genes was non-emm type specific. Several mutations within key regulatory genes were identified across the different GAS isolates, which may be linked to an increased expression of several virulence factors. This study from a single Australian centre provides a snapshot of non-emm1 GAS clinical isolates that are multiclonal and linked with distinct epidemiological markers commonly observed in high-income settings. These findings highlight the need for continual surveillance to monitor genetic markers that may drive future outbreaks.

Evaluating chemical venous thromboembolism prophylaxis in trauma patients at a single Australian center.

Trauma patients are at an elevated risk of developing venous thromboembolism (VTE), with the subsequent mortality in patients requiring intensive care unit admission ranging from 25% to 38%. There remains significant variability in clinical practice related to VTE prophylaxis in trauma patients due to the frequent presence of contraindications impacting the timing and consistency of application. This study aimed to assess the effectiveness of the current practice of chemical VTE prophylaxis in trauma patients at a single Australian center. A prospective review was conducted on patients admitted to the ACT Trauma Service (Canberra, Australia) from July to November 2022. The included patients were 18 years or older, without a direct contraindication to anticoagulation, who received chemical VTE prophylaxis with low-molecular-weight heparin (enoxaparin) for at least three doses and underwent subsequent testing of anti-factor Xa (aFXa) levels. During the study period, 187 patients were admitted, of whom 63 were included in the study. Of these, 47 patients achieved therapeutic levels of anticoagulation as determined by their aFXa levels, while 16 were subtherapeutic. The only statistically significant difference between the two groups was in weight, with patients in the subtherapeutic group weighing an average of 91.9 kg compared to 79.1 kg in the therapeutic group (P<0.05). A fixed-dose enoxaparin regimen was utilized, with limited individualization based on patient factors, such as injuries, comorbidities, and other biological factors. Sixteen patients (25%) had subtherapeutic VTE prophylaxis, as measured by aFXa levels. Higher weight was significantly correlated with inadequate VTE prophylaxis dosing. While age, sex, and smoking status might play important roles in clinical decision-making, weight-based dosing of low-molecular-weight heparin may be more effective in achieving adequate VTE prophylaxis.

Statin, aspirin and metformin use and risk of hepatocellular carcinoma related outcomes following liver transplantation: A retrospective study.

Liver transplantation (LT) is a potentially curative therapy for patients with hepatocellular carcinoma (HCC). HCC-recurrence following LT is associated with reduced survival. There is increasing interest in chemoprophylaxis to improve HCC-related outcomes post-LT. To investigate whether there is any benefit for the use of drugs with proposed chemoprophylactic properties against HCC, and patient outcomes following LT. This was a retrospective study of adult patients who received Deceased Donor LT for HCC from 2005-2022, from a single Australian centre. Drug use was defined as statin, aspirin or metformin therapy for ≥ 29 days, within 24 months post-LT. A cox proportional-hazards model with time-dependent covariates was used for survival analysis. Outcome measures were the composite-endpoint of HCC-recurrence and all-cause mortality, HCC-recurrence and HCC-related mortality. Sensitivity analysis was performed to account for immortality time bias and statin dosing. Three hundred and five patients were included in this study, with 253 (82.95%) males with a median age of 58.90 years. Aetiologies of liver disease were 150 (49.18%) hepatitis C, 73 (23.93%) hepatitis B (HBV) and 33 (10.82%) non-alcoholic fatty liver disease (NAFLD). 56 (18.36%) took statins, 51 (16.72%) aspirin and 50 (16.39%) metformin. During a median follow-up time of 59.90 months, 34 (11.15%) developed HCC-recurrence, 48 (15.74%) died, 17 (5.57%) from HCC-related mortality. Statin, aspirin or metformin use was not associated with statistically significant differences in the composite endpoint of HCC-recurrence or all-cause mortality [hazard ratio (HR): 1.16, 95%CI: 0.58-2.30; HR: 1.21, 95%CI: 0.28-5.27; HR: 0.61, 95%CI: 0.27-1.36], HCC-recurrence (HR: 0.52, 95%CI: 0.20-1.35; HR: 0.51, 95%CI: 0.14-1.93; HR 1.00, 95%CI: 0.37-2.72), or HCC-related mortality (HR: 0.32, 95%CI: 0.033-3.09; HR: 0.71, 95%CI: 0.14-3.73; HR: 1.57, 95%CI: 0.61-4.04) respectively. Statin dosing was not associated with statistically significant differences in HCC-related outcomes. Statin, metformin or aspirin use was not associated with improved HCC-related outcomes post-LT, in a largely historical cohort of Australian patients with a low proportion of NAFLD. Further prospective, multicentre studies are required to clarify any potential benefit of these drugs to improve HCC-related outcomes.

Drug Coated Balloon Angioplasty for Coronary In-Stent Restenosis: A West Australian Single Centre Experience

Drug Coated Balloon Angioplasty for Coronary In-Stent Restenosis: A West Australian Single Centre Experience

An Australian Single Centre Experience of Transcatheter Mitral Valve Replacement With the HighLife System

An Australian Single Centre Experience of Transcatheter Mitral Valve Replacement With the HighLife System

Drug-Coated Balloon Angioplasty for De Novo Coronary Artery Disease: A West Australian Single Centre Experience

Drug-Coated Balloon Angioplasty for De Novo Coronary Artery Disease: A West Australian Single Centre Experience

O-075 Particulate matter (PM2.5 and PM10) exposure prior to oocyte collection is associated with decreased live birth rates in subsequent frozen embryo transfers

Abstract Study question Does exposure to particulate matter air pollution prior to oocyte collection (OPU) or frozen embryo transfer (FET) impact FET live birth rates? Summary answer Increasing PM10 and PM2.5 exposure prior to OPU is associated with decreased odds of live birth in subsequent FET, independent of the conditions at FET. What is known already Ambient air pollution is increasing, and exposure is associated with adverse reproductive health outcomes, including infertility, miscarriage, preterm birth and low birth weight. Animal studies have shown that air pollutants can impair spermatogenesis, oogenesis, ovarian reserve and embryogenesis. These findings are corroborated by human epidemiological studies. The impact of ambient air pollution on IVF outcomes is uncertain. Additionally, whether pollutants exert a greater impact during oocyte development or early pregnancy is uncertain. Therefore, studies of FETs offer an opportunity to delineate different phases of reproduction that may be adversely affected by pollution. Study design, size, duration A retrospective analysis of 3,657 FETs in a single Australian centre from January 2013 – December 2021. All FETs during the study period were included; data were collected from the clinic database. Air pollutant concentrations for each day during the study were obtained from the Governmental monitoring body, including SO2, CO, O3, NO2, PM10 and PM2.5. Evaluation of FETs allowed separation of environmental effects during oocyte development and during early pregnancy. Participants/materials, setting, methods Quartiles were created for pollutants averaged over 24 hours, 2 weeks, 4 weeks and 3 months prior to OPU and prior to FET. Multi-pollutant models were created to account for co-exposures and were adjusted for variables at the time of OPU and FET. Bonferroni correction was made to account for the 4 timepoints tested on each outcome. Linear trends were assessed for each model, and pairwise comparisons against the first quartile were performed. Main results and the role of chance Overall, air quality was excellent, with pollutant levels within published safe limits on &amp;gt; 99% of days during the study period. Increasing PM10 exposure in the 2 weeks prior to OPU was associated with decreased odds of livebirth (linear trend p = 0.009); the odds of livebirth decreased by 38% when PM10 concentrations were in the highest quartile compared with the lowest (OR 0.62, p = 0.010). Increasing PM2.5 exposure in the 3 months prior to OPU was also associated with decreased odds of livebirth (linear trend p = 0.011). No significant linear trends were observed between livebirths and other pollutants. The summer seasonal association with livebirth that we have previously demonstrated consistently held in the multi-pollutant models. No significant linear trends were observed between air pollutants and biochemical pregnancy, clinical pregnancy, miscarriage, gestation at birth or embryological outcomes. Limitations, reasons for caution The retrospective design is a limitation. Whilst corrections were made for multiple pollutant co-exposures, other environmental conditions, patient factors and repeated cycles, we were unable to account for all potential covariates. To reduce the risk of type 1 error due to the multiple timeframes, we utilised a Bonferroni correction. Wider implications of the findings Even when PM2.5 and PM10 exposures are within so-called “safe” ranges, increasing exposure in the weeks and months prior to OPU are associated with decreasing livebirth rates, independent of the conditions at the time of FET. Trial registration number 2022/ET000980

Gastric intestinal metaplasia: Prevalence in a large Australian center and nationwide survey of endoscopic practice.

Atrophic gastritis (AG) and gastric intestinal metaplasia (GIM) are early changes in the stepwise progression to gastric adenocarcinoma. There is heterogeneity in international guidelines regarding the endoscopic diagnosis and surveillance of AG and GIM. This study aims to determine the prevalence of GIM in an Australian center and assess the approach of Australian endoscopists for these two conditions. We conducted a single-center retrospective study of adult patients between January 2015 and December 2020 diagnosed with GIM on gastric biopsy following upper gastric endoscopy. A web-based, 25-question, investigator-designed, multiple-choice survey was distributed among all registered endoscopists in Australia. The overall prevalence of GIM within a single Australian center was 11.7% over 5 years. Of the 1026 patients identified, only 58.7% underwent mapping biopsies using the modified Sydney protocol. Among the cohort, 1.6% had low-grade dysplasia, 0.9% had high-grade dysplasia, and 1.8% had malignancy on initial gastroscopy. Two hundred and sixty-seven (7.2%) endoscopists completed the survey, 44.2% indicated they would perform mapping for all patients, and 36% only for high-risk patients. Only 1.5% (n = 4) of respondents were able to correctly identify all six endoscopic photos of GIM/AG. This study demonstrates that in a large tertiary center, GIM is a prevalent endoscopic finding, but the associated rates of dysplasia and cancer were low. Additionally, among a small proportion of surveyed Australian endoscopists, there is notable variability in the endoscopic approach for AG and GIM and significant knowledge gaps. More training is required to increase the recognition of GIM and compliance with histological mapping.

Achieving a textbook outcome in patients undergoing gastric resections in a low incidence, high-volume Australian Upper GI unit

BackgroundTextbook outcome (TBO) has been proposed as a composite measure of quality in esophagogastric surgery, and achieving a TBO has been associated with improved overall survival (OS). The Dutch Upper Gastrointestinal Cancer Audit group determined their TBO rate for gastrectomy to be 32.1%, using 10 parameters. Our study aimed to assess the TBO rate in patients who had a gastrectomy for cancer in an Australian Upper GI unit, allowing for comparisons with international specialist centers. MethodsRetrospective analysis of a prospectively maintained database of patients who had a gastrectomy for cancer performed by the surgeons in a single Australian center between 2013 and 2018. Postoperative complications were analyzed using Clavien-Dindo (CD) ≥2 and CD ≥3 definitions. Baseline factors and their association with TBO were analyzed using multivariable logistical regression. The association between TBO and survival rates was determined by Cox proportional hazards regression analysis. ResultsIn 136 patients, 84 (62%) achieved a TBO when complications were graded as CD ≥2. Greatest negative impact on TBO was the complication rate, lymph node yield, and length of stay. Patients more likely to achieve a TBO were younger, with an increased body mass index and absence of underlying respiratory disease. A nonsignificant trend toward improved OS was seen when TBO was achieved. ConclusionOur TBO rate compares favorably with published data from high-volume centers. Assessment of a unit’s TBO may provide a stronger evaluation of quality when assessing where complex surgery should be performed within Australia.

Laparoscopic Cholecystectomy in Pregnancy: A Seven-Year Retrospective Study From an Australian Tertiary Center.

Background Cholecystectomy is the second most common non-obstetric indication for surgery during pregnancy; however, there is little recent literature specifically exploring perioperative care approaches, and a paucity of Australian data exists. This study investigates the incidence of laparoscopic cholecystectomy (LC) during pregnancy, peri-operative management, and post-operative outcomes in a single Australian tertiary center. Methods A retrospective analysis of LCs performed on pregnant patients between the ages of 16 and 50 years at a tertiary hospital between 2016 and 2023 was completed. Results Twenty-three patients underwent LC. The median gestational age was 17+4weeks (4+3-30+6). Cases were performed in all three trimesters, with the majority in the second trimester (n=12, 52.2%). Surgery indications were recurrent biliary colic (n=11, 47.8%), acute cholecystitis (n=8, 34.8%), and gallstone pancreatitis (n=4, 17.4%). Obstetrics and Gynecology (O&G) consultations occurred in 56.5% (n=13) of cases. Fetal heart rate (FHR) was recorded perioperatively in 82.6% (n=19) of cases. Preoperative steroids were given to 40% of eligible patients. An intraoperative cholangiogram was performed in 12 (52.2%) cases, of which eight (66.7%) utilized abdominal shielding. There was no perioperative maternal mortality nor fetal loss. Surgical morbidities were pancreatitis (n=1), bile leak (n=1), and intraoperatively recognized bile duct injury (n=1). Two threatened preterm labors and five (26.3%) preterm deliveries occurred. Conclusion Performing LC in pregnancy does carry a risk of major morbidity; however, there was no mortality or fetal loss across all trimesters. The decision to perform abdominal shielding during an intraoperative cholangiogram should be approached sensitively in a case-by-case manner, given recent paradigm shifts in radiology. A multidisciplinary approach with standardized local perioperative care policies regarding procedures such as O&G consultation, perioperative steroid use, and FHR monitoring is strongly recommended.

Feasibility Of DAH30 in a Single Australian Cardiac Centre

Postoperative days alive and at home within 30 days (DAH30) is a well described surrogate and quantitative measure of the quality of care received in hospital and the patient’s recovery. Time at home is an important patient-centred outcome that is highly valued by patients, clinicians, administrators, and the community. Days alive and at home within 30 days is a more sensitive measure of quality than the traditional postoperative length of stay, which does not detect early death or readmissions. It may also prove to be a useful benchmark between surgical centres and patient populations [ [1] Myles PS, Shulman MA, Heritier S, Wallace S, McIlroy DR, McCluskey S, et al. Validation of days at home as an outcome measure after surgery: a prospective cohort study in Australia. BMJ Open. 2017;7:e015828. Google Scholar ]. This study aimed to determine the feasibility of calculating DAH30 for cardiac surgical patients in a single Australian centre, with a view to proposing its calculation at Australian and New Zealand Collaborative Perfusion Registry (ANZCPR) registry sites across Australasia.

Use of Veno-Arterial Extracorporeal Membrane Oxygenation as a Bridge to Transplantation

Use of veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is a potential option to bridge critically unwell patients to heart transplantation. However, given the critically unwell nature of this patient cohort, morbidity and mortality are expectedly high, with previous literature reporting 30-day mortality of up to 30%. This study investigated the mortality of patients on preoperative VA-ECMO prior to heart transplantation in a single Australian centre.

Double barrelled uro-colostomy versus Ileal conduit for urinary diversion following pelvic exenteration: a single centre experience.

The ideal method for urinary diversion following total pelvic exenteration (TPE) remains unclear. This study compares the outcomes of double-barrelled uro-colostomy (DBUC) and ileal conduit (IC) in a single Australian centre. All consecutive patients who underwent pelvic exenteration with the formation of either a DBUC or an IC between 2008 and November 2022 were identified from the prospective database from the Royal Adelaide Hospital and St. Andrews Hospital. Demographic, operative characteristics, general perioperative, long-term urological and other relevant surgical complications were compared via univariate analyses. Of 135 patients undergoing exenteration, 39 patients were eligible for inclusion: 16 patients with a DBUC, and 23 patients with an IC. More patients in the DBUC group had previous radiotherapy (93.8% vs. 65.2%, P = 0.056) and flap pelvic reconstruction (93.7% vs. 45.5%, P = 0.002). The rate of ureteric stricture trended higher in the DBUC group (25.0% vs. 8.7%, P = 0.21), but in contrast, urine leak (6.3% vs. 8.7%, P>0.999), urosepsis (43.8% vs. 60.9%, P = 0.29), anastomotic leak (0.0% vs. 4.3%, P>0.999), and stomal complications requiring repair (6.3% vs. 13.0%, P = 0.63) trended lower. These differences were not statistically significant. Rates of grade III or greater complications were similar; however, no patients in the DBUC group died within 30-days or had grade IV complications requiring ICU admission compared with two deaths and one grade IV complication in the IC group. DBUC is a safe alternative to IC for urinary diversion following TPE, with potentially fewer complications. Quality of life and patient-reported outcomes are required.

Outcomes of immediate dental implants in vascularised bone flaps for mandibular reconstruction.

The aim of this study is to assess the outcomes of immediate implant placement for dental rehabilitation following mandibular reconstruction with vascularised bone flaps in a single Australian tertiary cancer centre. A retrospective analysis of patients who underwent immediate dental implant or delayed placement in vascularised bone flaps was performed. Primary outcome measures assessed included the number of implants placed, operative time, complication rates, time to radiotherapy initiation, dental rehabilitation rates and time to dental rehabilitation. In total, 187 dental implants were placed in 52 patients, of which 34 patients underwent immediate implant placement and 18 had delayed implant placement. There were no significant differences in the postoperative complication rate (32% immediate vs. 33% delayed, P=0.89) or time to postoperative radiotherapy (median 42 days immediate vs. 47 days delayed, P=0.24). Dental rehabilitation was achieved in 62% of the immediate cohort versus 78% of the delayed cohort. The time to be fitted with a dental prosthesis was significantly shorter in the immediate cohort (median 150 days immediate vs. 843 days delayed, P=0.002). The placement of immediate dental implants at the time of primary reconstruction of the mandible is a safe procedure and facilitates timely dental rehabilitation.

(930) Comparing Lung Donation after Circulatory Death to Donation after Brain Death in a Single Australian Centre

(930) Comparing Lung Donation after Circulatory Death to Donation after Brain Death in a Single Australian Centre

(676) Prevalence, Risk Factors and Outcomes for Scedosporium and Lomentospora spp. Following Lung Transplantation at a Single Australian Centre

(676) Prevalence, Risk Factors and Outcomes for Scedosporium and Lomentospora spp. Following Lung Transplantation at a Single Australian Centre

(704) Risk Factors for Persistent FEV1Decline Following COVID-19 Infection in Lung Transplant Recipients; a Single Australian Transplant Centre Experience

(704) Risk Factors for Persistent FEV1Decline Following COVID-19 Infection in Lung Transplant Recipients; a Single Australian Transplant Centre Experience

(705) Risk Factors for Death and Hospitalisation in COVID-19 Infection in Lung Transplant Recipients; a Single Australian Centre Experience

(705) Risk Factors for Death and Hospitalisation in COVID-19 Infection in Lung Transplant Recipients; a Single Australian Centre Experience

Transition from open to robotic distal pancreatectomy in a low volume pancreatic surgery country: a single Australian centre experience.

Advances in technology and techniques have allowed for robotic distal pancreatectomies to be readily performed in patients at high volume centres. This study describes the experience of a single surgeon during the learning curve and transition from open to robotic distal pancreatectomy in Australia, a traditionally low volume pancreatic surgery country. All patients undergoing distal pancreatectomy at an Australian-based tertiary referral centre between 2010 and 2021 were reviewed retrospectively. Demographic, clinicopathologic and survival data were analysed to compare perioperative and oncological outcomes between patients who underwent open, laparoscopic and robotic distal pancreatectomies. A total of 178 distal pancreatectomies were identified for analysis during the study period. Ninety-one open distal pancreatectomies (ODP), 48 laparoscopic distal pancreatectomies (LDP), and 39 robotic distal pancreatectomies (RDP) were performed. Robotic distal pancreatectomy was non-inferior with respect to perioperative outcomes and yielded statistically non-significant advantages over LDP and ODP. RDP is feasible and can be performed safely in well-selected patients during the learning phase at large pancreatic centres in a traditionally low-volume country like Australia. Referral to large pancreatic centres where access to the robotic platform and surgeon experience is not a barrier, and where a robust multidisciplinary team meeting can take place, remains pivotal in the introduction and transition toward the robotic approach for management of patients with pancreatic body or tail lesions.

P092 Humoral and T cell responses to COVID-19 vaccination in IBD

BackgroundThe characteristics of SARS-CoV-2 vaccine-induced immunity in inflammatory bowel disease (IBD) patients on immune modifying agents has not been clearly defined due to their exclusion in vaccine trials. Emerging results suggest infliximab impairs antibody response compared to vedolizumab. However there has not been direct comparison to controls. We evaluated this with both humoral and T cell response in IBD patients.MethodsAntibody and T cell response were analysed in IBD patients who received BNT162b2 (Pfizer–BioNTech) or ChAdOx1 nCoV-19 (Oxford–AstraZeneca) vaccination from a single Australian centre. The control group were healthcare workers (HCW) without IBD. Blood samples were taken at 4 time points: at baseline V0 (before vaccination); V1 (7–14 days after vaccine 1); V2 (7–14 days after vaccine 2); V3 (21–42 days after vaccine 2). Antibodies to the S1/2 IgG subunit and receptor-binding protein (RBD) were measured and reported here.Results88 (28 ulcerative colitis, 50 Crohn’s disease) IBD patients were included and compared to 53 healthy controls (Table 1). IBD patients medications included 6 5ASA (6.8%), 6 immunomodulator monotherapy (6.8%), 14 anti-TNF monotherapy (15.9%), 32 anti-TNF combination therapy with immunomodulator (36%), 16 IL12/23 (18%) and 13 vedolizumab (14%). Pre-vaccine baseline sera showed absence of anti-RBD antibodies in all participants. 84 patients (87%) received BNT162b2 and 4 (4.5%) received ChAdOx1 nCoV-19 vaccines. Geometric mean [SD] anti-S1/2 antibody concentrations at 4 weeks after second vaccination (V3) were significantly lower in IBD TNF treated patients (162.6[1.7]) compared to IBD non TNF treated patients (325.2[1.3]), and healthy controls (325.2[1.3]), p<0.0001 (Figure 1). There was no difference between non-TNF treated patients including those on vedolizumab or IL12/23 compared to controls. Similarly there was a significant difference between anti-RBD IgG titres between TNF and non-TNF IBD patients at V3 but not when compared to controls (Figure 2). There was no difference in RBD IgG and anti-S1/2 antibodies between anti-TNF monotherapy and combination anti-TNF with immunomodulator. All IBD and healthy controls seroconverted at V3 (Figure 3). ConclusionTNF agents influence SARS-CoV-2 vaccine-induced antibody response in IBD patients, with lower anti-S1/2 IgG concentrations compared to non-TNF IBD patients and healthy controls. However, there was no difference in RBD IgG titres between controls and IBD patients overall. It is unclear whether these subtle differences in antibody response in IBD patients on TNF agents is biologically meaningful, as all groups seroconverted after second dose vaccination. Neutralising antibody and T cell data (CD4+/CD8+) from this study to come.