Duplex sonography of the internal thoracic artery. Preoperative assessment

Ultrasonic duplex scanning was used to examine 211 internal thoracic arteries. The investigating vessels were classified as normal, abnormal, and occluded. The results of the duplex examination were compared with angiography as the reference method. The diameter measurements showed virtually no differences between the two methods. Normal internal thoracic arteries showed a continuous decrease of the systolic flow velocities from proximal to distal and a narrow to moderate spectral flow curve, whereas arteries classified as abnormal showed a velocity profile distinct from that--in particular, no decrease of the systolic peak velocities and an increased spectral broadening during systole with peak frequencies greater than 4 kHz at 60 degrees (> 1.2 m/sec). In occluded vessels no flow could be detected. The majority of changes were found in the proximal part of the internal thoracic artery. All lesions were detected by duplex sonography. Six normal vessels were misjudged as abnormal by the duplex method. The sensitivity, specificity, and accuracy of duplex sonography compared with angiography as the reference method were 100% (95% CI, 74.4% to 100%), 96.9% (95% CI, 93.2% to 98.8%), and 97.2% (95% CI, 93.6% to 98.8%), respectively. Duplex sonography is a reliable, noninvasive technique for the preoperative assessment of the internal thoracic artery. It allows the detection of potential atherosclerotic changes in the internal thoracic artery and the assessment of adequacy of caliber and flow.