Bilateral internal thoracic artery versus single internal thoracic artery: a meta-analysis of propensity score-matched observational studies

: The lack of benefit in terms of mid-term survival and the increase in the risk of sternal wound complications published in a recent randomized controlled trial have raised concerns about the use of bilateral internal thoracic artery (BITA) in myocardial revascularization surgery. For this reason, we decided to explore the current evidence available on the subject by carrying out a meta-analysis of propensity score-matched studies comparing BITA versus single internal thoracic artery (SITA). PubMed, EMBASE and Google Scholar were searched for propensity score-matched studies comparing BITA versus SITA. The generic inverse variance method was used to compute the combined hazard ratio (HR) of long-term mortality. The DerSimonian and Laird method was used to compute the combined risk ratio of 30-day mortality, deep sternal wound infection and reoperation for bleeding. Forty-five BITA versus SITA matched populations were included. Meta-analysis showed a significant benefit in terms of long-term survival in favour of the BITA group [HR 0.78; 95% confidence interval (CI) 0.71-0.86]. These results were consistent with those obtained by a pooled analysis of the matched populations comprising patients with diabetes (HR 0.65; 95% CI 0.43-0.99). When compared with the use of SITA plus radial artery, BITA did not show any significant benefit in terms of long-term survival (HR 0.86; 95% CI 0.69-1.07). No differences between BITA and SITA groups were detected in terms of 30-day mortality or in terms of reoperation for bleeding. Compared with the SITA group, patients in the BITA group had a significantly higher risk of deep sternal wound infection (risk ratio 1.66; 95% CI 1.41-1.95) even when the pooled analysis was limited to matched populations in which BITA was harvested according to the skeletonization technique (risk ratio 1.37; 95% CI 1.04-1.79). The use of BITA provided a long-term survival benefit compared with the use of SITA at the expense of a higher risk of sternal deep wound infection. The long-term survival advantage of BITA is undetectable when compared with SITA plus radial artery.