Pathophysiological significance of coronary collaterals for preservation of the myocardium during coronary occlusion and reperfusion in anaesthetised dogs.
The significance of pre-existing coronary collaterals for preservation of the myocardium during coronary occlusion and reperfusion was studied in anaesthetised open-chest dogs. The extent of myocardial ischaemic damage was assessed by the accumulation of calcium in the central zone of the ischaemic area and the size of myocardial infarct by the p-nitroblue tetrazolium staining method. Myocardial creatine kinase release was considered as an index reflecting both the extent of ischaemic myocardial damage and the size of the infarct. Reperfusion with the arterial blood of a main branch of the left coronary artery following the 60 min occlusion aggravated the ischaemic myocardial damage, as evidenced by exaggerated cardiac irregularity, myocardial calcium accumulation, and creatine kinase release. The myocardial calcium content and the logarithm of the creatine kinase release during reperfusion were linearly related to the infarct size. These parameters of myocardial damage were inversely related to the retrograde blood flow through the peripheral end of the occluded artery or the ratio of the retrograde-to-orthograde flow, indicating that the pre-existing collaterals influence preservation of the ischaemic myocardium. Thus, it is suggested that the collateral flow available during an ischaemic episode determines the viability of the myocardial cells during ischaemia, and in turn during reperfusion.
D000818:Animals; D002118:Calcium / Q000032:analysis; D003097:Collateral Circulation; D003327:Coronary Disease / Q000201:enzymology / Q000473:pathology / Q000503:physiopathology*; D003402:Creatine Kinase / Q000378:metabolism; D004285:Dogs; D005260:Female; D008297:Male; D009206:Myocardium / Q000032:analysis / Q000473:pathology*
D003402:Creatine Kinase; D002118:Calcium