Exploring Drug Re-Purposing for Treatment of Abdominal Aortic Aneurysms: a Systematic Review and Meta-analysis.

OBJECTIVE: Large abdominal aortic aneurysms (AAAs) present a significant mortality risk. While numerous medical interventions have been proposed, no drugs have convincingly reduced AAA progression, rupture rates, or repair risk. This systematic review and meta-analysis aimed to assess the impact of re-purposed drugs or dietary supplements on slowing expansion rates, reducing the risk of rupture, or minimising the risk of repair for individuals with AAA. METHODS: A systematic search was conducted in five databases. Both observational studies and randomised controlled trials were included. Unpublished data from two screening trials were incorporated. Risk of bias was assessed using the Newcastle-Ottawa scale and revised Cochrane risk of bias tool. Meta-analyses were performed for each identified drug subclass and were stratified by overall risk of bias. Results were reported following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. RESULTS: Of 7 484 screened studies, 39 met the inclusion criteria. No studies on dietary supplements were included. A total of 84 cohorts were derived from the included studies, and twelve distinct drug groups underwent meta-analyses. Two drug groups, metformin and statins, were statistically significant in slowing AAA growth. No low risk of bias studies were included for these two drug groups, and the results had very high heterogeneity (I2 > 80%). Both groups had a GRADE certainty of very low. Metformin, excluding high risk of bias studies, presented an estimated mean growth difference of AAA diameter between users and non-users of -0.73 mm/year, whilst statins had an overall estimated mean difference of -0.84 mm/year. CONCLUSION: This systematic review and meta-analysis suggests that metformin and statins may provide some effect in slowing AAA progression. However, no definitive evidence was found for any of the investigated drugs included in this study. Further research is needed to identify effective medical treatments for AAA progression with more robust methodology.

Simulation Based Training and Assessment in Open Vascular Surgery: A Systematic Review.

OBJECTIVE: The aim of this study was to systematically review the literature and give evidence based recommendations for future initiatives for simulation based training (SBT) and assessment in open vascular surgery. DATA SOURCES: PubMed, Embase, and the Cochrane Library. REVIEW METHODS: A systematic review of PubMed, Embase, and the Cochrane Library was performed, with the last search on 31 March 2020, to identify studies describing SBT and assessment in open vascular surgery. Kirkpatrick's levels for efficacy of training were evaluated. Validity evidence for assessment tools was evaluated according to the recommended contemporary framework by Messick. RESULTS: Of 2 844 studies, 51 were included for data extraction. A high degree of heterogeneity in reporting standards and varying types of simulation was found. Vascular anastomosis was the most frequently simulated technical skill (43%). Assessment was mostly carried out using the Objective Structured Assessment of Technical Skills (55%). Validity evidence for assessment tools was found using outdated frameworks, and only one study used Messick's framework. Self directed training is valuable, the low trainer to trainee ratio is important to maximise efficiency, and experienced vascular surgeons are the most effective trainers. CONCLUSION: Carefully designed and structured SBT is effective and can improve technical skills, especially in less experienced trainees. However, the supporting evidence lacks homogeneity in the reporting standards and types of simulations. Pass/fail standards that support proficiency based learning and studies investigating skills transfer should be the focus in future studies. Validity evidence of assessment tools needs to be addressed using contemporary frameworks.