Assessment of internal thoracic artery graft with intraoperative color doppler ultrasonography

Background. Intraoperative ultrasonography has the potential to provide anatomic and functional information about internal thoracic artery (ITA) graft, but this potential has been hindered by the relatively large standard probe. In this study, we used a color Doppler microprobe to evaluate ITA grafts. Methods. The subjects were 15 consecutive patients who underwent elective coronary artery bypass grafting either with cardiopulmonary bypass (n = 14) or without (n = 1). All patients underwent anastomosis of the left ITA to the left anterior descending artery. The ITA graft was assessed before the chest was closed, with the microprobe placed directly on the graft. Results. A good-quality color Doppler image of the ITA graft was easily obtained in all 15 patients within a few minutes. The ITA graft function was assessed by analyzing the shape of the pulsed Doppler wave. All ITA grafts were patent, and the mean graft diameter was 1.8 ± 0.04 mm. The peak systolic velocity, peak diastolic velocity, and mean velocity were 52.0 ± 14.9 cm/s, 58.3 ± 22.4 cm/s, and 36.5 ± 10.9 cm/s, respectively. The ratio of peak diastolic velocity to peak systolic velocity was 1.24 ± 0.66. The ITA graft seemed to function well when the biphasic diastolic predominant flow appeared. The mean blood flow was 55.1 ± 22.0 mL/min. Conclusions. Intraoperative ultrasonography using the microprobe provides adequate anatomic and hemodynamic information regarding ITA grafts. As the Doppler flow evaluation has high sensitivity and specificity, we suggest that intraoperative ultrasonography is useful for the assessment of these grafts.