Intraoperative assessment of Native Coronary Artery and Bypass Graft Flow Using a 15 MHz Linear Array Transducer

ABSTRACT

BACKGROUNDS The internal mammary artery graft (IMAG) showed a gradual transition in the phasic flow pattern from predominant systolic velocity proximally at the origin from the subclavian artery to the predominant diastolic velocity distal to the anastomosis with coronary artery. IMAG without significant stenosis showed a typical pulsed Doppler flow pattern similar to that of coronary artery characterized by a predominant diastolic component. On the other hand, patients with occluded IMAGs or IMAGs with severe stenosis, low velocity profiles were recorded during diastole with an increase in the systolic component. OBJECTIVES: Identifying abnormal graft flow intraoperatively could allow for immediate graft revision. The aim of this study was to test the feasibility of using a new ultrasound 15 MHz linear array transducer. METHODS: In six patients (MF=42, mean age=69+/-11 yrs), a 15 MHz linear array probe with a sterile cover was placed directly on native coronary arteries and grafts after anatomosis. 2-dimensional image, color and pulsed Doppler signals of native coronary arteries, IMA, saphenous vein and penetrating intramyocardial coronary arteries (PICA) were observed. RESULTS: 1) 2-dimensional image and color flow signals of all grafts and native coronary arteries were visualized. 2) The flow pattern of pulsed Doppler signals of all native coronary arteries including PICA were diastolic dominant. 3) The diastolic dominant pattern typical of a patent grafts on pulsed Doppler were obtained at anastomosis site of graft vessels. 4) The intimal thickening of right coronary artery was also visualized on 2-dimensional images. CONCLUSION: A new echo Doppler probe can be useful for intraoperative assessment of graft flow during bypass surgery.