What should the health services and regulatory agencies take into account?

Abstract

It is generally accepted that in most patients with acute myocardial infarction only reperfusion therapy offers the chance to reduce myocardial infarct size and mortality. Before we begin to calculate the costs of different thrombolytic treatments, we must try to outline the possible beneficial effect of reperfusion on infarct size. If the results of collateral or residual blood flow at the acute event are superimposed on the development of infarcts in different animal species with a known amount of collateral blood flow, we can expect the following pattern of infarct development (2). Figure 1 shows that three groups of patients can be separated. Group A has no angiographically visible collateral blood flow, group B has a faint visible collateral blood flow, and group C has good collateral or residual blood flow. About 40% of the patients with acute myocardial infarction belong to group A, 35% to group B, and the remaining 25% to group C. Ultimate infarct size in group A is supposed to be reached within 90 min of ischemia, and is about 85–100% when considered as the percentage of the risk region. In group B, final infarct size will be reached within 3 hours and is in the range of 60–85%. Ultimate infarct size in group C varies between 0 or 1 % and 60%. In group C it is difficult or impossible to predict when the final infarct size is reached. Figure 1 suggests that reperfusion after 90 min of ischemia may reduce infarct size in about 60% of the patients, and reperfusion after 3 h of ischemia reduces infarct size in only 25% of the patients.