CORONARY COLLATERAL CIRCULATION BEHAVIOR AND MYOCARDIAL VIABILITY IN CHRONIC TOTAL OCCLUSION TREATED WITH CORONARY ANGIOPLASTY

Aims We explored the role of microcirculation integrity following the chronic occlusion of an infarct-related artery to assess the behaviour of collateral circulation during and after reperfusion by coronary an gioplasty Methods and Results Eighteen patients with a proximally occl uded left anterior descending artery and firm evidence of intercoronar y collateral circulation were studied with selective coronary angiogra phy and selective intracoronary myocardial contrast echocardiography, before coronary angioplasty, and at 5 and 15 min and 12 h later. Myoca rdial enhancement during myocardial contrast echocardiography was eval uated with a semiquantitative score (0-3), which was correlated to bas al and 6 months' regional left ventricular wall motion results. 16/18 procedures were successfully performed; four patients with an inadequa te acoustic window were excluded. Restenosis was evident at the 6 mont hs' follow-up in two patients. Basal myocardial contrast echocardiogra phy indicated that 81/192 segments from the left anterior descending c oronary artery and 90/192 from the right coronary artery were perfused ; no perfusion was observed in 21 segments either before or after coro nary angioplasty. After coronary angioplasty, the angiographic interco ronary collateral circulation immediately disappeared, and myocardial contrast echocardiography revealed that there was a progressive reduct ion of segments perfused by the right coronary artery and an increase in segments perfused by the left anterior descending coronary artery. Regional left ventricular wall motion analysis demonstrated that there was abnormal motion in 51/192 segments. There was no improvement in s egments with score 0 and abnormal motion after 6 months (100% sensitiv ity), but 16/17 segments with score 3 did show an improvement (98% spe cificity). The predictive value of intermediate scores (1-2) in detect ing long-term improvement, was only 43%. Conclusion These data show th at the adaptive mechanism observed in the behaviour of epicardial and microvascular circulation after reperfusion of a chronic occluded infa rct-related artery call vary. In addition, this study clearly shows th at microvascular integrity detected by myocardial contrast echocardiog raphy can provide myocardial viability.