Preoperative evaluation of the right internal thoracic artery for coronary surgery.

In general, the right internal thoracic artery (ITA) is used less frequently as a graft than the left ITA in coronary artery bypass grafting. To determine whether there is an anatomic or hemodynamic rationale for the underuse of the right ITA, noninvasive measurements of right and left ITAs were performed in 171 patients before the bypass procedure. Transthoracic visualization of both vessels was accomplished using a color-flow duplex scanner (5.0-MHz probe) through the third intercostal space. The diameter (in millimeters), peak systolic velocity (in centimeters per second), and end-diastolic velocity (in centimeters per second) were measured in all but 2 patients. The mean right ITA diameter was 2.7 +/- 0.6 mm, the mean peak systolic velocity was 100 +/- 29 cm/s, and the mean end-diastolic velocity was 6 +/- 5 cm/s. Diameter and flow velocity measurements for the right and left ITA were similar in all patients (p = not significant). The measured values for both sites were independent of age and sex, or the presence of hypertension or diabetes mellitus (p = not significant). We conclude that no morphologic or physiologic differences exist between the right and left ITAs. The findings from this study indicate that color-flow duplex ultrasound imaging is a safe and reliable noninvasive technique in the preoperative assessment of the anatomic and functional characteristics of the right ITA before coronary artery bypass grafting.