Safety of different carotid artery revascularization strategies in the coronary artery bypass graft population: study protocol for a systematic review and network meta-analysis

Background Concomitant significant carotid artery occlusive diseases (CAOD) increase the risk of perioperative stroke and death in patients who undergo coronary artery bypass graft (CABG). Although several surgical strategies can be used in the management of such patients, controversy still surrounds which is the best option for CABG patients with accompanying CAOD. Methods Literature searches will be conducted covering articles published in PubMed, the Cochrane Central Register of Controlled Trials, Web of Science, and Embase between January 1989 and December 2019. Search results will be limited to articles published in English. Six surgical strategies using carotid endarterectomy (CEA) or carotid artery stenting (CAS) with different timings (i.e., before, after, or combined with CABG) will be evaluated. Randomized controlled trials and non-randomized studies comparing these strategies will be included. The quality of studies will be critically appraised using the Cochrane risk-of-bias tool or ROBINS-I tool. Since CEA and CAS have comparable effectiveness for the treatment of significant CAOD, we will integrate direct and indirect evidence using network meta-analysis (NMA) to create hierarchies of the six surgical strategies based on their perioperative safety. The primary outcomes will be the probability of perioperative stroke and the probability of perioperative death. Additionally, we will analyze the probability of perioperative myocardial infarction (MI) as a secondary outcome. Pairwise meta-analyses and Bayesian network meta-analyses will be performed for all related outcome measures. Subgroup analyses, sensitivity analyses, and network meta-regression will be conducted to assess the robustness of the findings. Discussion This NMA will summarize the direct and indirect evidence of perioperative safety with the aim of providing a ranking of the various surgical strategies. The results of this meta-analysis will provide useful information on optimal surgical management of CABG patients with concomitant significant CAOD. Trial registration number PROSPERO CRD42020162611.