[Duplex scanning of the internal thoracic artery for coronary artery surgery]

Ultrasonic duplex scanning was used to examine 77 internal thoracic arteries (ITA). The investigated vessels were classified as normal, stenosed (peak systolic velocity was faster than 150 cm/sec and doppler signals showed turbulent pattern), small (diameter measurements were smaller than 1.4 mm and mean flow velocities were slower than 20 cm/sec in distal part of the vessels), and occluded (no flow characteristics could be detected) by the doppler spectrum analysis and the two-dimensional B-mode images. The results of the duplex examination were compared with operative findings and angiograpic findings. Diameter measurements by duplex scanning compared with operative findings showed virtually no differences. One stenosed ITA, a 75% stenosis in the proximal part of the vessel, and two small ITAs were detected by duplex scanning. We performed coronary artery bypass grafting using distal part of the stenosed ITA as a free graft, and used small ITAs as individual bypass grafts. Two normal ITAs were misjudged as small, and one small ITA was misjudged as occluded. All normal ITAs of duplex examination showed normal findings of angiography. Duplex scanning is a reliable, sensitive, and noninvasive technique for the preoperative assessment of the ITA, and is a suitable screening for coronary artery surgery.