Transcutaneous Assessment of Blood Flow in Internal Thoracic Artery to Coronary Artery Grafts

The internal thoracic (internal mammary) artery is now the preferred conduit for aortocoronary bypass grafts to the left anterior descending coronary artery, and in many cases also to the right and left circumflex coronary arteries [1, 2]. The use of transcutaneous duplex ultrasound to study blood flow in internal thoracic to coronary artery grafts was pioneered by Fusejima and colleagues [3] and Kyo and colleagues [4]. It has also been studied by Sons and colleagues in Dusseldorf [5] and by our own group in Leicester [6]. Canver and colleagues [7] have used duplex ultrasound to assess internal thoracic artery patency before grafting. This chapter reviews the anatomical and technical aspects of ultrasound flow measurement in internal thoracic artery grafts, discusses the interpretation of the waveform patterns seen, and considers the possible uses of ultrasound flow measurement in studying the physiology and pathophysiology of the coronary circulation.