Epicardial Colour-Doppler Scanning of Coronary Artery Stenoses and Graft Anastomoses

Abstract

Objective : Epicardial ultrasound scanning was applied during coronary surgery to assess coronary artery stenoses and quality of distal graft anastomoses, with special emphasis to the left anterior descending artery (LAD). Design : Twenty-three patients with coronary artery disease (M:F 19:4, mean age 65.0 - 9.5 years) had coronary artery bypass grafting (CABG) on cardiopulmonary bypass. Intraoperative scanning of coronary artery stenoses and graft anastomoses was performed with a new 10 MHz linear array Vingmed transducer connected to a GE Vingmed System FiVe echocardiography unit. Coronary stenoses detected by ultrasound were compared with preoperative angiograms. Intraoperatively, coronary graft flow was assessed with a Medi-Stim transit-time flowmeter. Results : Twenty LADs were investigated. In 17 LADs (85%) stenoses were clearly identified. In three LADs (15%) stenoses were not identified because LADs were deeply intramyocardial or the stenosis was very proximal. There was a significant correlation between LAD stenoses detected by ultrasound and angiogram ( R = 0.7; p < 0.01). Mean number of grafts was 3.8 - 0.9. Of 26 LAD anastomoses assessed, good images were obtained in 22 cases (84.4%); the mean LAD diameter measured 1 cm below the anastomosis was 1.6 - 0.2 mm. In two LADs images were rated fair and in two LADs images were poor because of intramyocardial LAD. No technical error of the anastomoses was detected. All grafts had good flows as ascertained by flow measurements. Conclusion : Epicardial ultrasound scanning with the new 10 MHz transducer allowed satisfactory imaging of coronary stenoses and graft anastomoses. Factors limiting the quality of imaging are proximal lesions, intramyocardial vessel, vessel tortuosity, and extensive calcifications. Epicardial ultrasound scanning with updated technology should become a further advancement to graft assessment during off-pump coronary surgery.