Use rate and outcome in bilateral internal thoracic artery grafting: Insights From a systematic review and meta-analysis

Background--This meta-analysis was designed to assess whether center experience affects the short- and long-term results and the relative benefits of bilateral internal thoracic artery grafting (BITA) for coronary artery bypass grafting. Methods and Results--MEDLINE and EMBASE were searched to identify all articles reporting the outcome of BITA in patients undergoing coronary artery bypass grafting. The BITA center experience was gauged according to the percentage use of BITA in the institutional overall coronary artery bypass grafting population (%BITA). The primary outcome was long-term all-cause mortality. Secondary outcomes were operative mortality, perioperative myocardial infarction, perioperative stroke, deep sternal wound infections (DSWIs), and major postoperative adverse event. The rates of the primary and secondary outcomes were calculated after adjusting for %BITA. Primary and secondary outcomes were also compared between the BITA and the single internal thoracic artery arms in the adjusted studies. Meta-regression was used to evaluate the effect of %BITA on the primary and secondary outcomes. Thirty-four studies (27 894 patients undergoing BITA) were included. In the pooled analysis, the incidence rate for long-term mortality was 2.83% (95% confidence interval, 2.21%-3.61%). %BITA was significantly and inversely associated with long-term mortality and the rate of DSWI. In the pairwise comparison, %BITA was significantly and inversely associated with the risk of longterm mortality and DSWI in the group undergoing BITA. Conclusions--BITA series with higher %BITA report significantly lower long-term mortality and DSWI rate as well as higher longterm survival advantage and lower relative risk of DSWI in their BITA cohort. These findings suggest that a specific volume-outcome relationship exists for BITA grafting.