TRANSCUTANEOUS ULTRASOUND ASSESSMENT OF INTERNAL THORACIC ARTERY TO CORONARY-ARTERY GRAFTS IN PATIENTS WITH AND WITHOUT ISCHEMIC SYMPTOMS

Objective-To evaluate transcutaneous duplex ultrasound in the assessme nt of internal thoracic artery to coronary artery grafts. Setting-Regi onal cardiothoracic centre. Methods-Prospective duplex ultrasound eval uation of 83 consecutive patients undergoing left internal thoracic ar tery to coronary artery grafts, together with combined angiographic an d duplex ultrasound evaluation of 17 patients with suspected recurrent myocardial ischaemia after internal thoracic artery grafting. Results -The grafted internal thoracic artery was imaged in 65 (78%) of 83 con secutive postoperative patients, and in 13 (75%) of 17 patients with s uspected graft dysfunction. Grafts were recognised by their characteri stic position and biphasic blood flow pattern. Resting graft flow was estimated from the time averaged velocity and graft cross sectional ar ea. Median resting flow in patients without ischaemic symptoms was 36 ml/min (interquartile range 24 to 49 ml/min). Of 13 patients with recu rrent ischaemia in whom the graft could be imaged, nine patients with estimated flow in the lowest quartile or abnormal flow profiles, or bo th, had graft disease or anastomotic problems on angiography, while fo ur with satisfactory graft flow on ultrasound examination had normal g raft flow on angiography, but had evidence of native disease progressi on in other vessels. Two of four patients in whom it was not possible to image the graft on ultrasound had satisfactory graft function on an giography. Conclusions-For those patients whose artery graft can be tr anscutaneous duplex ultrasound is a helpful non-invasive guide to graf t function. The main limitations to the technique are an inability to image the graft in about 20% of patients, and possible inaccuracy in e stimating graft diameter.