2. MATERIALS AND METHODS

This systematic review is conducted following the Preferred Reporting Items for Systematic Reviews And Meta-Analyses (PRISMA) statement.8 No ethical approval or patient consent was sought for the review, which is based on all previously published studies.
2.1 Search Strategy
A systematic search was carried out across major databases of MEDLINE via Ovid, PubMed, Embase, the Cochrane Library Database and Google Scholar until August 2022 to identify eligible studies using Boolean operators to achieve maximum sensitivity. The terms used are “CABG”, “Coronary artery bypass grafting”, “Cardiac surgery”, “Antiplatelet”, “Aspirin”, “Clopidogrel”, “Antithrombotic”, “Mortality”, “Morbidity”, “Graft patency”, “Survival”, “Resistance”, and “Platelet mapping”. Bibliographies of relevant studies were also screened manually to identify additional suitable studies.
2.2 Study Selection & Data Extraction
The inclusion criteria include human studies with patients undergoing CABG surgery who are on antiplatelet, and the studies must report at least one outcome in patients with antiplatelet resistance such as vein graft failure, mortality or morbidity. Animal studies, case reports and case series, review articles and non-English articles are excluded.
Two authors independently searched the databases, reviewed the potentially relevant articles, extracted data and evaluated the quality and risk of bias of the included studies. Any discrepancies were resolved by consensus or by escalating to the third author.
2.3 Risk of Bias Assessment
The quality of observational cohort studies was evaluated using the Newcastle-Ottawa Scale (NOS) with scores greater than 6 regarded as high-quality studies.9 The 2015 Updated Method Guidelines for Systematic Reviews in the Cochrane Back and Neck Group was used for quality assessment of randomised controlled trials, and studies are deemed the low risk of bias if they meet at least 6 criteria.10