Evaluation of the coronary artery bypass graft.

It is thirty-five years since the initial coronary artery bypass graft (CABG) was performed in Japan in 1970. There was more risk in surgery in the early days, and many efforts have been made to decrease the mortality rate. Since the 1980’s when I was training to be a heart surgeon, surgical outcomes have improved, and the number of surgical cases has been steadily increasing. Since the long-term outcomes are good, the arterial graft is frequently used, and off-pump CABG is most frequently utilized because of its low invasiveness. Evaluation of patency and blood supplying ability of bypass grafts is very important for CABG regardless of the graft type or surgical method, CABG is functional surgery; not perfomed for healing constrictive lesions of the coronary arteries. After introduction of the bypass graft in Japan, palpation of pulsation with hands or measurement of blood flow using a very inaccurate electromagnetic flowmeter was used as an intraoperative evaluation of bypass graft. These methods were not capable of determing if an anastomosis was successful. Postoperative graft angiography was the only reliable method of graft evaluation at that time. However, graft angiography was performed after completion of surgery, and thus, only the results of surgery were evaluated. Re-operation cannot be perfomed immediately after surgery, even if the likely outcome is poor. Moreover, angiography investigates only the patency and the condition of the anastomosed region by imaging, and sufficient functional evaluation of the graft cannot be obtained. The method, in which, Cardiogreen dye is injected into a venous graft during surgery, and the speed and area of staining are visually determined to judge if the surgery was successful, were one of the intraoperative evaluation methods. However, this method is not applicable for arEvaluation of the Coronary Artery Bypass Graft