What is the best graft to supplement the bilateral internal thoracic artery to the left coronary system? A meta-analysis

This meta-analysis was designed to assess the effect of the use of arterial conduits (ACs) versus great saphenous vein (GSV) grafts as a third conduit for revascularization of the right coronary artery system, in addition to the bilateral internal mammary artery on the left coronary artery. PubMed and OVID's version of MEDLINE were searched from January 2000 to September 2017 for relevant publications. The primary end point was the long-term mortality rate. The secondary end point was early mortality, defined as either in-hospital death or death within 30 days after the operation. Meta-regression was used to evaluate the effect of female gender and diabetes on the primary and secondary outcomes. A total of 10 studies (4121 patients) were selected for the systematic review and meta-analysis comparing ACs (1619) versus the GSV (2502), 6 (2548) comparing the GSV (2548) versus the right gastroepiploic artery (1023) and 5 comparing the GSV (2548) versus the radial artery (596). The pooled analysis did not show any difference between ACs and the GSV in terms of long-term mortality rates [hazard ratio (HR) = 0.75, 95% confidence interval (CI) = 0.56-1.01; P = 0.061]. When using the leave-one-out analysis, after the exclusion of 1 study (outlier), ACs were significantly associated with lower long-term mortality rates (HR = 0.67, 95% CI = 0.54-0.83; P < 0.001). When the results were stratified according to the type of study, no differences with regard to long-term results were found between ACs and the GSV, either in the pooled analysis of the 6 propensity score-matched studies (HR = 0.69, 95% CI = 0.43-1.08; P = 0.107) or in the pooled analysis of the 4 non-propensity score-matched studies (HR = 0.88, 95% CI = 0.62-1.23; P = 0.438). Again, when the outlier was excluded, the pooled analysis of the propensity score-matched studies confirmed that ACs were associated with lower long-term mortality rates (HR = 0.58, 95% CI = 0.43-0.80; P < 0.001). Comparisons between the GSV and either the right gastroepiploic artery or the radial artery showed similar results. No publication bias was found. This meta-analysis is the first to compare the GSV to the radial artery and the right gastroepiploic artery for right coronary artery grafting in patients receiving a bilateral internal mammary artery to left coronary artery. The choice of a third AC seems to be preferable in order to achieve better long-term survival.