The coronary collateral circulation may be beneficial in protecting against myocardial ischemia or necrosis and sustaining contractile function when flow is impaired as a result of progressive coronary artery stenosis or occlusion. So it is important to assess the development of the collateral vessels. Lately, with the rapid development of the molecular biological technique, many angiogenic peptide growth factors have been used to enhance collateral development to ischemic myocardium and the therapeutic angiogenesis may offer an alternative therapy in patients with intractable myocardial ischemia not amenable to percutaneous transluminal coronary angioplasty (PTCA) or coronary artery bypass graft (CABG). However, it is currently controversial whether gene therapy could induce formation of stable new collateral system and improve myocardial perfusion because of the lack of motheds to examine intramyocardial collateral circulation. Color Doppler Coronary Flow Imaging (CDCFI) and Myocardial Contrast Echocardiography (MCE) are new developed ultrasonic techniques to study coronary flow and myocardial microcirculation. In this series of experimental studies, we evaluate the values of CDCFI in observation of the coronay collateral circulation and assessment of the angiogenesis induced by direct intramyocardial...
|