The tight tie of MAG versus SAG in CABG

Abstract

For a new technique to be adopted, it must be user-friendly but it also must prove it adds value for patients. We agree with Fudulu and Angelini in the fact that improving vein grafts is one path we should pursue [ [1] Fudulu D.P. Angelini G.D. Two Arteries Better than One? The jury is still out. International Journal of Cardiology. 2020; (in press) Abstract Full Text Full Text PDF Scopus (1) Google Scholar ]. However, we believe there is also much space for improvement in the research design area. Indeed, the complexity of equipoise and influence of surgical expertise are herculean challenges for randomized clinical trials (RCTs) [ [2] Gaudino M. Kappetein A.P. Di Franco A. et al. Randomized trials in cardiac surgery. J. Am. Coll. Cardiol. 2020; 75: 1593-1604 Crossref PubMed Scopus (22) Google Scholar ]. Dissimilar results raised on two almost simultaneously published meta-analyses, addressing the multiple (MAG) vs single arterial grafting (SAG) question, due to different studies type included, only RCTs [ [3] Changal K. Masroor S. Elzanaty A. et al. Meta-analysis comparing multiple arterial grafts versus single arterial graft for coronary-artery bypass grafting. Am. J. Cardiol. 2020; 130: 46-55 Abstract Full Text Full Text PDF PubMed Scopus (6) Google Scholar ] and both RCTs and observational propensity-score studies [ [4] Saraiva F.A. Leite-Moreira J.P. Barros A.S. Lourenço A.P. Benedetto U. Leite-Moreira A.F. Multiple versus single arterial grafting in coronary artery bypass grafting: A meta-analysis of randomized controlled trials and propensity score studies. Int J Cardiol. 2020; ([published online ahead of print, 2020 Aug 6] (in press)) Abstract Full Text Full Text PDF PubMed Scopus (6) Google Scholar ]. Although observational studies are prone to selection bias and confounding, they represent the everyday practice; while traditional RCTs have low external validation, high costs, need for numerous staff and heavy documentation leading to low adherence from surgeons [ [5] Zolin S.J. Petro C.C. Prabhu A.S. et al. Registry-based randomized controlled trials: a new paradigm for surgical research. J. Surg. Res. 2020; 255: 428-435 Abstract Full Text Full Text PDF PubMed Scopus (8) Google Scholar ]. Registry-based RCTs, pragmatic RCTs with enhanced generalizability of results, lower costs and quicker enrolment, constitute a new paradigm for surgical research [ [5] Zolin S.J. Petro C.C. Prabhu A.S. et al. Registry-based randomized controlled trials: a new paradigm for surgical research. J. Surg. Res. 2020; 255: 428-435 Abstract Full Text Full Text PDF PubMed Scopus (8) Google Scholar ]. Considering the high impact of surgeons' preferences and their expertise in specific techniques that has been reported as a significant effect modifier [ [6] Gaudino M. Benedetto U. Bakaeen F. et al. Off- versus on-pump coronary surgery and the effect of follow-up length and Surgeons’ experience: a meta-analysis. J. Am. Heart Assoc. 2018; 7e010034 Crossref PubMed Scopus (40) Google Scholar ], the possibility of randomizing patients quickly after the first pre-operative evaluation (after filling the baseline variables of registries), would allow the allocation of each patient to a surgical team who performs the randomized technique on a daily basis, instead of picking individual surgeons to enter RCTs and perform the randomized technique even if it is not his/her standard. Cardiac surgery centres should be encouraged to be included at wide registries, allowing the implementation of registry-based RCTs to answer surgical questions in parallel with the traditional RCTs to enhance the global available data.