2.3. Data extraction
Three investigators (AS, JL, AM) independently identified and extracted all relevant data of eligible studies from original articles: first author’s name, year of publication, numbers of patients, median age at surgery, gender, surgical strategy of myocardial revascularization, number of grafts, and endpoints such as graft patency, early and long-term mortality and need of interventional procedures and/or surgical re-interventions. Data were retrieved only from the articles, and no attempt was made to get missing data from the authors. Any disagreement was solved by consensus.