Fate of the Coronary Microvasculature in Infarcting Canine Myocardium: Role of Collateral Blood Flow

Abstract

It has been shown in many studies (for review see¹) that occlusion of a left coronary descending artery in an initial phase produces ultrastructural symptoms of myocardial ischemia that finally pass the phase from reversible to irreversible injury, i.e. infarction. Duration of coronary artery occlusion, actual oxygen consumption of the left ventricle, and absence or presence of collateral perfusion have been shown² to be factors modifying the speed of development of infarction, but after 24–48 hrs the final infarct size of 80% of the area at risk will, nevertheless, be present. Collateral blood vessels apparently do not influence very significantly final infarct size, but they greatly modify the process of infarction, as will be described in the following text. All data relate to ultrastructural observations made on cardiac tissue from dog hearts subjected to experimental myocardial infarction by occlusion of a coronary artery.