Effect of Percutaneous Transluminal Coronary Angioplasty on Myocardial Perfusion : Measurement with Myocardial Contrast Echocardiography

ABSTRACT

BACKGROUND: Myocardial contrast echocardiography(MCE) has been known to be a safe and useful method to assess the adequacy of myocardial perfusion. This study was performed to assess the change of myocardial perfusion following successful percutaneous transluminal coronary angioplasty using MCE in the patients with significant coronary arterial obstructive diseases. METHODS: The study comprised of eight patients(mean age 55 years, male 7, female 1). Four patients were unstable angina and four patients post non-Q wave myocardial infarction angina. Six patients had one vessel disease and two paients two vessel disease. All patients underwent successful PTCA at the proximal(2 patients) and the mid(6 patients) left anterior descending coronary artery. Pre- and post-PTCA myocardial perfusion was assessed by comparing peak contrast intensity and slope of time-intensity curve after injection of hand-agitated Hexabrix(6cc) respectively. The variables were measured off-line at thirty two end-diastolic frames of the left ventricle in each patient. RESULTS: 1) Diameter stenosis of target lesion changed from 91±9 to 24±14% after successful coronary angioplasty(p < 0.005). 2) Peak contrast intensity was increased from 47.4±30.7 to 64.9±36.4 gray scale U/pixel in anteroseptal segment and from 46.6±14.3 to 67.9±35.8 gray scale U/pixel in anterior segment(p < 0.05). 3) The slope of time-intensity curve after PTCA became more steeper compared to that of pre-PTCA(anteroseptal −0.32±0.48 vs −0.76±0.66 p=0.071, anterior −0.33±0.39 vs −0.81±0.80 p=0.086). 4) During the study, there was no significant clinical or hemodynamic complications except three patients who developed transisient sinus bradycardia after intracoronary injection of handagitated Hexabrix. CONCLUSION: Myocardial contrast echocardiography appeared to be safe and useful in the evaluation of myocardial perfusion following coronary angioplasty assessed by the changes of peak contrast intensity and slope of contrast time-intensity curve.