ORCID Profile
0000-0001-5372-7674
Current Organisations
Flinders University
,
Flinders Medical Centre
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Publisher: Springer Science and Business Media LLC
Date: 26-07-2021
DOI: 10.1007/S00464-021-08646-0
Abstract: In iduals with Barrett's esophagus are believed to be at 30-120× risk of developing esophageal adenocarcinoma (EAC). Early detection and endoscopic treatment of dysplasia/early cancer confers a significant advantage to patients under surveillance however, most do not progress past the non-dysplastic state of Barrett's esophagus (NDBE), which is potentially an inefficient distribution of health care resources. This article aimed to review the outcomes of cost-effectiveness studies reducing low-value care in the context of endoscopic surveillance for non-dysplastic Barrett's esophagus (NDBE). A systematic search was conducted by two reviewers in accordance with PRISMA guidelines. cost-utility analyses of endoscopic surveillance of NDBE patients with at least one treatment strategy focused on reduction of surveillance. A narrative synthesis of economic evaluations was undertaken, along with an in-depth analysis of input parameters contributing to stated Incremental cost-effectiveness ratios (ICER). Study appraisal was performed using the consolidated health economic evaluation reporting standards (CHEERS) tool. 10 Studies met inclusion criteria. There was significant variation in cost-model structures, input parameters, ICER values, and willingness-to-pay thresholds between studies. All studies except one concluded guideline-specified endoscopic surveillance for NDBE patients was not cost-effective. Studies that explored a modified surveillance by deselection of low-risk NDBE patients found it to be a cost-effective strategy. Guideline specified endoscopic surveillance for NDBE was not found to be cost-effective in the studies examined. A modified endoscopic surveillance strategy removing in iduals with the lowest risk for progression from NDBE to adenocarcinoma is likely to be cost-effective but is dependent on risk profile of patients excluded from surveillance.
Publisher: Wiley
Date: 09-03-2021
DOI: 10.1111/ANAE.15458
Abstract: Peri‐operative SARS‐CoV‐2 infection increases postoperative mortality. The aim of this study was to determine the optimal duration of planned delay before surgery in patients who have had SARS‐CoV‐2 infection. This international, multicentre, prospective cohort study included patients undergoing elective or emergency surgery during October 2020. Surgical patients with pre‐operative SARS‐CoV‐2 infection were compared with those without previous SARS‐CoV‐2 infection. The primary outcome measure was 30‐day postoperative mortality. Logistic regression models were used to calculate adjusted 30‐day mortality rates stratified by time from diagnosis of SARS‐CoV‐2 infection to surgery. Among 140,231 patients (116 countries), 3127 patients (2.2%) had a pre‐operative SARS‐CoV‐2 diagnosis. Adjusted 30‐day mortality in patients without SARS‐CoV‐2 infection was 1.5% (95%CI 1.4–1.5). In patients with a pre‐operative SARS‐CoV‐2 diagnosis, mortality was increased in patients having surgery within 0–2 weeks, 3–4 weeks and 5–6 weeks of the diagnosis (odds ratio (95%CI) 4.1 (3.3–4.8), 3.9 (2.6–5.1) and 3.6 (2.0–5.2), respectively). Surgery performed ≥ 7 weeks after SARS‐CoV‐2 diagnosis was associated with a similar mortality risk to baseline (odds ratio (95%CI) 1.5 (0.9–2.1)). After a ≥ 7 week delay in undertaking surgery following SARS‐CoV‐2 infection, patients with ongoing symptoms had a higher mortality than patients whose symptoms had resolved or who had been asymptomatic (6.0% (95%CI 3.2–8.7) vs. 2.4% (95%CI 1.4–3.4) vs. 1.3% (95%CI 0.6–2.0), respectively). Where possible, surgery should be delayed for at least 7 weeks following SARS‐CoV‐2 infection. Patients with ongoing symptoms ≥ 7 weeks from diagnosis may benefit from further delay.
Publisher: Wiley
Date: 22-01-2021
DOI: 10.1111/ANS.16586
Abstract: Economic evaluations are increasingly becoming part of the surgical evidence base. With health and research guidelines emphasizing both clinical and economic benefits, surgeons will need to consider the impact of economic evaluations in the future. It seems reasonable that surgical costs in the public healthcare sector should be justified by the benefits that clinical interventions offer. Thus, it is vital to understand the methodological differences, reported outcomes and limitations of economic evaluations pertinent to surgical practice as well. As terminology and concepts can be unfamiliar to surgeons, understanding results from these studies can seem difficult. This article aims to inform surgical readers of the processes involved in performing economic evaluations to determine and compare the cost‐effectiveness of treatments. The various types of economic evaluations, their uses, design characteristics, model parameters, interpretation of outputs, uncertainty analyses and notable limitations are considered. Through a hypothetical clinical ex le that compares costs and effects of surgical versus medical treatment for cancer, key concepts in economic evaluations are considered.
Publisher: MDPI AG
Date: 25-06-2019
Abstract: Background and Objectives: Electrocautery adenoidectomy (ECA) is a common procedure performed in paediatric otolaryngology. ECA has been preferred over curettage adenoidectomy due to its lower intraoperative bleeding rates, decreased procedure time, and higher subjective success. However, post-ECA symptoms of pain and halitosis have never been studied. The objective of our study was to identify the pattern of post-ECA halitosis and pain in the paediatric population. Materials and Methods: This is a single centre, prospective observational study that uses visual analogue scales (VAS) by parent proxy to assess post-ECA pain and halitosis in paediatric patients (age 18) in South Australia. A total of 19 patients were enrolled in the study and followed for seven days. Results: Postoperative pain and halitosis reaches a peak 3 days post-ECA (median = 2 for pain median = 6 for halitosis) but resolves 7 days post-ECA (median = 0 for both). Conclusions: Our study demonstrates that halitosis and pain occur over a seven-day period in patients undergoing ECA and will resolve post-operatively with simple analgesia and without antibiotics.
Publisher: Springer Science and Business Media LLC
Date: 23-11-2020
DOI: 10.1038/S41598-020-77297-3
Abstract: Brain embryonic periventricular endothelial cells (PVEC) crosstalk with neural progenitor cells (NPC) promoting mutual proliferation, formation of tubular-like structures in the former and maintenance of stemness in the latter. To better characterize this interaction, we conducted a comparative transcriptome analysis of mouse PVEC vs. adult brain endothelial cells (ABEC) in mono-culture or NPC co-culture. We identified 6000 differentially expressed genes (DEG), regardless of culture condition. PVEC exhibited a 30-fold greater response to NPC than ABEC (411 vs. 13 DEG). Gene Ontology (GO) analysis of DEG that were higher or lower in PVEC vs. ABEC identified “Nervous system development” and “Response to Stress” as the top significantly different biological process, respectively. Enrichment in canonical pathways included HIF1A, FGF/stemness, WNT signaling, interferon signaling and complement. Solute carriers (SLC) and ABC transporters represented an important subset of DEG, underscoring PVEC’s implication in blood–brain barrier formation and maintenance of nutrient-rich/non-toxic environment. Our work characterizes the gene signature of PVEC and their important partnership with NPC, underpinning their unique role in maintaining a healthy neurovascular niche, and in supporting brain development. This information may pave the way for additional studies to explore their therapeutic potential in neuro-degenerative diseases, such as Alzheimer’s and Parkinson’s disease.
Publisher: Oxford University Press (OUP)
Date: 24-03-2021
DOI: 10.1093/BJS/ZNAB101
Abstract: Preoperative SARS-CoV-2 vaccination could support safer elective surgery. Vaccine numbers are limited so this study aimed to inform their prioritization by modelling. The primary outcome was the number needed to vaccinate (NNV) to prevent one COVID-19-related death in 1 year. NNVs were based on postoperative SARS-CoV-2 rates and mortality in an international cohort study (surgical patients), and community SARS-CoV-2 incidence and case fatality data (general population). NNV estimates were stratified by age (18–49, 50–69, 70 or more years) and type of surgery. Best- and worst-case scenarios were used to describe uncertainty. NNVs were more favourable in surgical patients than the general population. The most favourable NNVs were in patients aged 70 years or more needing cancer surgery (351 best case 196, worst case 816) or non-cancer surgery (733 best case 407, worst case 1664). Both exceeded the NNV in the general population (1840 best case 1196, worst case 3066). NNVs for surgical patients remained favourable at a range of SARS-CoV-2 incidence rates in sensitivity analysis modelling. Globally, prioritizing preoperative vaccination of patients needing elective surgery ahead of the general population could prevent an additional 58 687 (best case 115 007, worst case 20 177) COVID-19-related deaths in 1 year. As global roll out of SARS-CoV-2 vaccination proceeds, patients needing elective surgery should be prioritized ahead of the general population.
Publisher: Elsevier BV
Date: 05-2014
DOI: 10.1016/J.BRAINRES.2014.03.018
Abstract: Interactions between neural progenitor cells (NPC) and endothelial cells (EC) from adult vascular beds have been well explored previously. However, the factors and signaling mechanisms that regulate neurogenesis and angiogenesis are most prevalent during embryonic development. This study aimed to determine whether embryonic brain endothelial cells from the periventricular region (PVEC) present an advantage over adult brain EC in supporting NPC growth and differentiation. PVEC were isolated from E15 mouse brains, processed, and sorted with immunomagnetic beads using antibodies against CD31/PECAM. On immunofluorescence (IF) staining, nearly all cells were positive for EC markers CD31 and CD144/VE-Cadherin. In proliferation studies, NPC proliferation was highest in transwell co-culture with PVEC, approximately 2.3 fold increase compared to baseline versus 1.4 fold increase when co-cultured with adult brain endothelial cells (ABEC). These results correlated with the PVEC mediated delay in NPC differentiation, evidenced by high expression of progenitor marker Nestin evaluated by IF staining. Upon further characterization of PVEC in an angiogenesis assay measuring cord length, PVEC exhibited a high capacity to form cords in basal conditions compared to ABEC. This was enhanced in the presence of NPC, with both cell types displaying a preferential structural alignment resembling neurovascular networks. PVEC also expressed high Vegfa levels at baseline in comparison to NPC and ABEC. Vegfa levels increased when co-cultured with NPC. We demonstrate that PVEC and NPC co-cultures act synergistically to promote the formation of a neurovascular unit through dynamic and reciprocal communication. Our results suggest that PVEC/NPC could provide promising neuro-regenerative therapies for patients suffering brain injuries.
Publisher: BMJ
Date: 11-01-2013
DOI: 10.1136/NEURINTSURG-2012-010589
Abstract: Extradural arteriovenous fistulae (AVFs) are vascular malformations that result from a direct connection between an extradural artery and vein, resulting in a high flow fistula that drains into the epidural venous system. Extradural AVFs may cause myelopathy when distended epidural veins compress the cord or when venous hypertension causes venous stasis within the spinal cord, and are uncommon causes of subarachnoid hemorrhage (SAH), although the presence of intracranial drainage is a risk factor for SAH. There are numerous reports of SAH and AVF with rostral intracranial venous drainage, implying an intradural drainage pathway. To our knowledge, a cervical spinal AVF at the craniovertebral junction (occurring between the occiput and C2) with exclusively extradural drainage and without a significant epidural component has not been described previously. A retrospective review was performed identifying three patients treated at our hospital with cervical spinal AVF and extradural venous drainage. We present three cases of cervical spinal AVF with exclusive extradural venous drainage without accompanying intradural drainage--cranial or spinal. All three patients with exclusively extradural drainage have done well after 24 months of follow-up. The anatomical, clinical, and radiologic features are presented. Patients with cervical AVF and exclusively extradural drainage pathways form a separate entity, representing a subset with a less ominous natural history.
Publisher: British Institute of Radiology
Date: 11-12-2017
DOI: 10.1259/BJR.20170560
Publisher: Wiley
Date: 12-07-2021
DOI: 10.1111/ANS.17040
Abstract: The Lyell McEwin Hospital entered into a public–private collaborative agreement in 2019 in order to access Da Vinci® Xi Surgical Systems (Intuitive Surgical, Sunnyvale, CA, USA) in private hospitals. This study aimed to examine the costs associated with usage of robot surgical systems under the agreement, and the potential for acquisition in the public hospital. Retrospective data on robotic‐assisted and equivalent operations performed between 1 May 2019 and 30 April 2020 were collected and formed subsequent model inputs. Cost data were from hospital records and the local Da Vinci® Xi distributor. Clinical workflow of operations was simulated with a decision‐analytic model, with output being costs incurred. The model's base case scenario assumed 5% of cases were robotically assisted. A total of 35 robotic‐assisted, 101 laparoscopic and 34 open operations were performed. Patients were predominantly male and overweight with multiple comorbidities. Length of stay and duration of operation were associated with increased costs ( p 0.001, r 2 0.72). In the base case scenario, there was a cost of AU$26 424 per patient, with an open conversion rate of 11%. Increasing robotic‐assisted case percentage resulted in reduced cost, open conversion rates and length of stay. Extrapolation of cost model data indicated if 50% were robotic‐assisted cases, then the initial capital investment (assumed at AU$4 000 000) could be recovered in 10 years. Our model highlights potential advantages of performing greater numbers of robotic‐assisted operations in a collaborative environment. Cost‐effective analysis with prospective data could evaluate if these results are translatable and potentially support acquisition of robotic systems in the public sector.
Publisher: Elsevier BV
Date: 06-2020
Location: United States of America
No related grants have been discovered for Ravi Vissapragada.