Linear relationship between perfusion area and infarct size.

The purpose of this study was to develop a technique measuring the perfusion area of the coronary artery preocclusively and to study the relationship between the perfusion area and infarct size. 125I tracer microspheres were selectively injected into the left circumflex coronary artery (LCX) preocclusively, and then the LCX was ligated. 48 hours later the heart was removed, rapidly frozen, and 50-mu transverse sections were obtained from base, middle and apex of the canine left ventricle, and used for autoradiography to measure perfusion area and for tetrazolium staining to measure infarct size. Dogs were divided into 2 groups: group 1 in which the main trunk of the LCX was occluded to produce large infarct (n = 10) and group 2 in which the distal branch of the LCX was occluded to produce small infarct (n = 10). There was a linear correlation between the perfused and infarcted area regardless of a size or location of the perfusion area involved. These results indicate that the extent of infarction is directly proportional to the perfusion area and is not altered by the location in the ventricle.