COLOR-FLOW DUPLEX ULTRASOUND ASSESSMENT OF INTERNAL THORACIC ARTERY GRAFT AFTER CORONARY-BYPASS

In an effort to develop a noninvasive method to evaluate now character istics of the internal thoracic artery (ITA) graft after coronary arte ry bypass grafting, we performed color-now duplex ultrasound studies o f the right and left ITAs of 42 patients before and 5 weeks after bypa ss grafting. The ITA was visualized with a duplex scanner (5.0-MHz pro be) through the first or second intercostal space. We recorded the dia meter, peak systolic velocity, and end-diastolic velocity for each pat ient. Preoperative measurements of the native ITAs were obtained easil y in all patients. Postoperatively, the unused right ITA was seen in a ll patients. Postoperative visualization of the left ITA graft was ade quate to make reliable measurements in 40 patients (95%). Postoperativ e end-diastolic velocities of the unused right ITA and the left ITA gr aft were markedly higher than the preoperative end-diastolic velocitie s of the native ITAs (p < 0.001). Whereas there was a marked increase in the peak systolic velocity of the postoperative unused right ITA (p < 0.05), the postoperative peak systolic velocity of the left ITA gra ft was significantly lower than the preoperative value (p < 0.001). We conclude that postoperative visualization of the left ITA graft is po ssible with the use of color-flow duplex ultrasound. Ultrasonic survei llance of postoperative ITAs may reveal ITA graft velocity abnormaliti es before overt graft failure is manifested in the patient who has und ergone coronary artery bypass grafting.