Intraoperative echocardiographic imaging of coronary arteries and graft anastomoses during coronary artery bypass grafting without cardiopulmonary bypass

Abstract

Background: No accepted approach exists for the intraoperative evaluation of the quality of coronary arteries and the technical adequacy of graft anastomoses during coronary artery bypass grafting without cardiopulmonary bypass. Methods and Results: We assessed the accuracy of high-frequency epicardial echocardiography and power Doppler imaging in evaluating coronary arteries during coronary artery bypass grafting without cardiopulmonary bypass. To validate measurements of coronary arteries and graft anastomoses by high-frequency epicardial echocardiography and power Doppler imaging, we compared luminal diameters determined by these methods with diameters determined histologically in a study of off-pump coronary artery bypass grafting in 20 dogs. Technical errors were deliberately created in 10 grafts (stenosis group). The results of these animal validation studies showed that the maximum luminal diameters of coronary arteries and graft anastomoses measured by high-frequency epicardial echocardiography (HEE) and power Doppler imaging (PDI) correlated well with the histologic measurements: HEE = 1.027 × Histologic measurements + 0.005 (P <.0001); PDI = 0.886 × Histologic measurements + 0.0453 (P =.0001). Similar results were found in the evaluation of the stenosis group: PDI = 0.991 × Histologic measurements + 0.074 (P <.0001). Subsequently, we demonstrated the clinical applicability of this approach in 12 patients who underwent minimally invasive or off-pump coronary artery bypass grafting. Twenty graft anastomoses were examined intraoperatively by highfrequency epicardial echocardiography and power Doppler imaging, and luminal diameters determined by power Doppler imaging were compared with those determined by postoperative coronary angiography. The results demonstrated that graft anastomosis by power Doppler imaging correlated well with the angiographic measurements: PDI = 1.018 × Angiographic measurements – 0.106 (P <.0001). Conclusion: High-frequency epicardial echocardiography can provide meaningful information on the target coronary artery, and power Doppler imaging can accurately measure graft anastomoses and can detect technical errors and inadequacies during coronary artery bypass grafting without cardiopulmonary bypass.