Clinical and Experimental Studies on Angiogenesis of Coronary Collateral Vessels

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Clinical significance of Coronary Collateral CirculationWe found that there is a significant difference in the proportion of patients with post-infarction angina between those with pre-infarction angina but unsuccessful thrombolysis (67%) and those who had neither pre-infarction angina nor recanalization (13%). This suggests that the developed collateral circulation accompanying pre-infarction angina renders myocardial tissue viable in the perfusion territory of the infarct-related coronary artery and causes post-infarction angina because of its limited flow reserve. We also demonstrated that in 10 patients with acute myocardial infarction who had a significant collateral circulation to the infarct-related coronary artery and unsuccessful reperfusion, the left ventricular aneurysm was observed in only one patient (10%), while in 12 patients with unsuccessful recanalization in the absence of a significant collateral perfusion, there was a significantly higher incidence (7/12, 58%) of le … More ft ventricular aneurysm formation. These findings indicate that the well-developed collateral circulation can prevent the left ventricular aneurysm formation probably because of a salutary functional effect of viable islands of residual subepicardial cells in the infarct zone on infarct expansion. In patients with stable effort angina, exercise with heparin pretreatment definitely improved the exercise capability associated with an increase in the extent of opacification of collaterals to the jeopardized myocardium. The development of such a therapeutic modality may attenuate the deleterious sequelae due to coronary artery disease.Effects of Myocardial Ischemia Coronary Collateral CirculationWe reported the importance of myocardial ischemia for the recruitment of a native collateral circulation. The collateral flow after 5 1 min or a 5 min coronary occlusion was significantly qreater than after 30 10 sec coronary occlusions, where the total occlusion time was identical. We compared the effects of repeated 1 min or 2 min coronary occlusions on the development of collateral circulation. The relative contribution of the first and second 1 min of coronary occlusion to the collateral development was mathematically evaluated. The second 1 min of coronary occlusion was 4.43 fold more effective than the first 1 min of occlusion. Because the extent of myocardial ischemia is more severe during the second 1 min of coronary occlusion, it was concluded that severe ischemia is crucial for the collateral development. Our data indicated the importance of myocardial ischemia for both recruitment and development of coronary collateral circulation. Less