Contrast echocardiography and myocardial perfusion

New clinical applications for myocardial contrast echocardiography (MCE) are being developed in both the operating room and the catheterization laboratory. Studies have shown that red blood cell transit time through the myocardium is a measure of myocardial blood flow. Sonicated albumin microbubbles can mimic intramyocardial behavior of red blood cells. Other studies have used MCE to assess collateral flow to determine myocardial viability after acute myocardial infarction. The authors have developed a computer system that allows on-line quantitation of contrast echocardiographic data in the operating room, and this system is able to confirm that bypass grafts are properly placed. The ability to quantitate myocardial flow with MCE may be useful in guiding the sequence of graft placement and for assessing the success of the operation. These measures will help lower the incidence of perioperative infarction. Experiments in our laboratory using the canine model have shown that MCE may be useful in assessing the intramyocardial distribution of retrogradely delivered cardioplegia. This technique may, therefore, assist the surgeon in determining the adequacy of retrograde cardioplegia delivery and may improve myocardial preservation during bypass surgery.