Noninvasive assessment of internal thoracic artery for reoperative coronary artery surgery.
To determine whether previous sternotomy alters internal thoracic artery (ITA) anatomy and flow characteristics, a duplex scanner was used for noninvasive evaluation of the ITA in 59 patients who were scheduled for reoperative coronary artery bypass surgery. The left ITA was insonated through the third intercostal space by use of a duplex scanner (5.0 MHz probe). Measurements of the ITA diameter (mm) and peak systolic velocity (cm/sec) were obtained; ITA flow was calculated from velocity and cross-sectional area. These findings were compared with the values obtained from 105 patients who were scheduled to undergo first-time (primary) coronary artery surgery during the same time period. In the reoperative group, preoperative mean ITA diameter was 2.26 +/- 0.06 mm; this was not significantly different from the primary group's mean ITA diameter of 2.15 +/- 0.04 mm (p = 0.09). Mean peak systolic velocity was 79.9 +/- 2.4 cm/sec and calculated systolic blood flow was 204.6 +/- 13.1 ml/min in the reoperative patients, as compared with 83.3 +/- 2.1 cm/sec and 189.5 +/- 8.6 ml/min in the primary group, respectively. Values were similar in both groups for the peak systolic velocity (p = 0.31) and calculated systolic blood flow (p = 0.32). These results suggest that previous heart surgery or sternotomy does not adversely affect ITA anatomy and flow characteristics. We conclude that ultrasonic imaging is an easily applicable technique for preoperative assessment of ITA in patients who have undergone previous sternotomy.