A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether bilateral internal thoracic artery (BITA) coronary bypass increases the risk for mediastinitis. Using the reported search 140 papers were identified. Twenty-four papers represented the best evidence on the subject and the author, journal, date and country of publication, patient group studied, study type, relevant outcomes, results and study comments and weaknesses were tabulated. In general, BITA grafting carries a 2.5- to 5-fold higher risk for mediastinitis after CABG. This risk is about 1.3-4.7% in non-diabetic patients compared to 0.2-1.2% for single internal thoracic artery (SITA) grafting. For diabetic patients with BITA grafting the risk of mediastinitis is significantly increased and can be as high as >10% in some series. However, for patients who undergo BITA harvest using skeletonization the risk is significantly lower and may be similar to patients receiving SITA graft only at around 0.4-2.6%. BITA grafting can be performed with acceptable risk in all patients including higher risk patients such as diabetics, in whom skeletonization of the internal thoracic arteries should be strongly considered rather than pedicled harvest.
