Quantitative assessment of microcollateral recruitment during coronary occlusion using real-time intravenous myocardial contrast echocardiography

Background: Residual collateral-derived myocardial blood flow (MBF) (A X beta) is important to protect against myocardial ischemia after acute coronary occlusion. Methods: Recruitment of microcollateral was assessed in 22 dogs with left circumflex coronary artery occlusion by analysis of MBF and regional wall thickening (WT) using real-time myocardial contrast echocardiography. Results: Video intensity and WT at the center of risk area were significantly lower than those at the border of risk area. The video intensity, A value, P value, and MBF correlated well with WT after left circumflex coronary artery occlusion. The WT of the area with above 25% of normal MBF was preserved and was higher than that at below 25%. However, the deterioration of WT was not distinguished according to A value. Conclusion: Real-time myocardial contrast echocardiography is a useful noninvasive method to evaluate collateral-derived MBF, which can be a reliable index of protection against myocardial ischemia.