Evaluation of regional myocardial perfusion in areas of old myocardial infarction after revascularization by means of intraoperative myocardial contrast echocardiography

Because myocardial revascularization to areas of old myocardial infarction brings about functional recovery to some extent to myocytes in those areas, the assessment of regional myocardial perfusion on those areas after myocardial revascularization may allow myocardial viability to be estimated. Using intraoperative myocardial contrast echocardiography by direct injection of 2 ml sonicated 5% human albumin into saphenous vein grafts, we assessed regional myocardial perfusion in 16 revascularized areas of old myocardial infarction. We estimated the myocardial viability of areas with respect to myocardial perfusion, and we compared these results to both the improvement of regional wall motion after myocardial revascularization (increase in segmental wall thickening during systole) and relative thallium 201 activity obtained by quantitative analysis of preoperative exercise myocardial thallium 201 distribution on delayed images. The background-subtracted peak peak intensity of myocardial enhancement and the ratio of endocardial to epicardial intensity were determined in each revascularized area. An inverse correlation existed between peak intensity (18 +/- 7) and the endocardial/epicardial ratio (0.88 +/- 0.17) (r = -0.63, p < 0.01). A good correlation was found between peak intensity and both the percent increase in segmental wall thickening (r = 0.73, p < 0.005) and the relative thallium 201 activity (r = 0.81, p < 0.005). These results suggested that regional myocardial perfusion after myocardial revascularization in areas of old myocardial infarction distributed better to the epicardial halves than to the endocardial halves, and that the peak intensity could be related to myocardial viability.