Coronary risk area measurement by intracardiac echocardiography and ultrasound contrast

The perfusion bed of an occluded coronary artery-the coronary risk area-determines infarct size. Our objective was to evaluate the combined techniques of intracardiac echocardiography (ICE) and ultrasound contrast echocardiography for real-time estimation of the coronary risk area in an experimental model. We studied 13 pigs and 2 dogs. The left anterior descending coronary was occluded by inflating coronary balloons. An ultrasound contrast agent was injected either through the dilation catheter (distal to the inflated balloon) directly into the occluded artery to opacify the "positive" risk area or into the aortic root during coronary balloon inflation to determine the nonopacified "negative" risk area. Evans blue dye was injected into the occluded artery to stain the risk area, allowing an independent measurement. The mean left anterior descending negative risk area was 26% +/- 10% of the left ventricular myocardial area, the mean positive risk area was 24% +/- 10%, and the Evans blue-stained risk area was 25% +/- 9%. By Bland-Altman analysis, the positive Optison-Evans blue mean +/- SD difference was 1.42% +/- 6.42%; the negative Optison-Evans blue mean +/- SD difference was 1.02% +/- 7.56%. Coronary risk area can be determined with intracardiac echocardiography and ultrasound contrast.