Objectives: We analyzed the safety and feasibility of myocardial echocardiography with intracoronary injection of contrast, its effect on left ventricular remodeling and systolic function, and its relationship with angiography and magnetic resonance imaging (MRI) for the evaluation of post-infarction coronary microcirculation.
Patients and method: Thirty patients with a first ST-elevation myocardial infarction and a patent infarct-related artery were studied. Mean perfusion score of the infarcted area was analyzed with myocardial echocardiography. TIMI and Blush grades (angiography) were determined. Mean perfusion score (MRI-perfusion), end-diastolic volume index and ejection fraction were determined with MRI. At 6 months all studies were repeated in the first 17 patients.
Results: Forty-seven perfusion studies (30 in the first week and 17 after 6 months) were done without complications (6 [2] min per myocardial echocardiography study). Normal perfusion (myocardial echocardiography 0.75) was detected in 67% of the patients. Myocardial echocardiography was the best predictor of end-diastolic volume (r=-0.69; P =.002) and ejection fraction (r=0.72; P=.001) after 6 months. Normal perfusion was observed in 80% of the patients with TIMI grade 3, and in 14% of those with TIMI grade 2. Of the 40 studies in patients with TIMI grade 3, normal perfusion was seen in 85% of the patients with Blush grade 2-3 and in 50% of those with Blush 0-1. Perfusion was also normal in 90% of the patients with MRI-perfusion =1 and in 62% of those with MRI-perfusion < 1.
Conclusions: Myocardial echocardiography is a feasible and relatively rapid technique with no side effects. This technique provided the most reliable perfusion index for predicting late left ventricular remodeling and systolic function. To achieve normal perfusion, TIMI grade 3 is necessary but does not guarantee success. In patients with TIMI grade 3, a normal Blush score or a normal MRI-perfusion study suggests good reperfusion.