DOES THE INTERNAL THORACIC ARTERY GRAFT DELAY THE RECOVERY OF MYOCARDIAL-METABOLISM

Background. The left internal thoracic artery (LITA) bypass graft to t he left anterior descending artery has greater long-term patency than a saphenous vein graft. However, surgeons may be reluctant to use the LITA graft in some patients because they are unable to deliver cardiop legia to the left anterior descending artery territory. Methods. We co mpared the myocardial levels of high-energy phosphates and their metab olites in patients who received an LITA graft with those in patients w ho received a saphenous vein graft to the left anterior descending art ery territory during elective coronary artery bypass grafting. Right a nd left ventricular biopsy specimens were obtained at three times: bef ore aortic crossclamping, after cross-clamp removal, and after 10 minu tes of reperfusion. Results. No differences were found between the LIT A graft group and the saphenous vein graft group in any right ventricu lar metabolites. There was an improvement in myocardial protection ove r time and a higher proportion of LITA graft patients in the late time period (early group, 63% versus late group, 80%; p < 0.01). Within ea ch time period, there were no differences between the LITA and sapheno us vein graft groups. Among patients receiving cold antegrade cardiopl egia, the myocardial levels of high-energy phosphates were better pres erved in those receiving an LITA graft. Conclusions. Advances in myoca rdial protection have led to improved preservation of high-energy phos phate levels after cardioplegic arrest. In patients undergoing electiv e coronary artery bypass grafting, the use of an LITA graft does not a dversely affect myocardial metabolism. Further investigations are requ ired to determine the effects of the use of the LITA during urgent or emergent procedures.