Objective: To examine the efficacy of the intravenous myocardial contrast echocardiography (MCE) for detection of the territory of the coronary bypass graft.
Methods: The subjects were 5 beagles having a bypass tube between the left circumflex and carotid artery. MCE was performed with bolus injection of Optison during short axis view recording using harmonic and ECG-triggered modes of every two cardiac cycles. Time video-intensity curve was obtained at the lateral (perfused by the bypass) and the septal wall (perfused by the native coronary artery). Their peak intensities and time interval between these two peaks were measured. Selective MCE into the bypass tube was performed to confirm the territory of the bypass. Flow volume of the bypass was also measured.
Results: The bypass area was clearly recognized by delayed opacification in comparison with the native coronary artery's area. Time lag of opacification between the two areas showed a good hyperbolic correlation with bypass flow, and was almost identical to the theoretically calculated time lag (r=0.889, p<0.0001).
Conclusion: Both the area and flow volume of coronary bypass were diagnosed by using intravenous MCE.
