The scintigraphic identification of "severe myocardial ischemia"

Both perfusion scintigraphy and blood pool scintigraphy have been shown to have a high sensitivity and excellent specificity for the diagnosis of coronary artery disease. Particularly helpful in those patients where the diagnosis remains in doubt or is ambiguous, scintigraphic methods have, previously tended to underestimate the degree of coronary vascular involvement. Identification of patients with main left and triple vessel coronary disease is extremely critical as these lesions have been shown to relate to an extremely high risk in terms of morbidity and mortality and since this risk has been shown to be reduced by invasive treatment. While the extent of stress induced wall motion abnormalities and the degree of functional abnormality induced by stress suggests extensive coronary involvement, quantitative methods of radial analysis and wash-out have been applied to perfusion scintigraphy, providing objectivity and increasing the ability to identify the full extent of vascular involvement. Additionally, nonperfusion scintigraphic indicators as lung uptake, cavitary dilatation and basal uptake have, in the presence of coronary disease, demonstrated a relationship to extensive myocardial ischemia and multivessel disease. Numerous studies have now indicated the increased ability of scintigraphic methods to identify such "high-risk" coronary patients. Furthermore, the pathophysiologic nature of scintigraphic analysis permits the differentiation of the degree of coronary involvement from the true risk factor, the extent of myocardium at ischemic risk. In the setting of myocardial infarction, acute scintigraphic indicators often aid the direction of therapy and provide means for assessment of therapeutic effects. Additionally, scintigraphic measures of the extent of infarction, related ischemia and function have all demonstrated prognostic abilities.(ABSTRACT TRUNCATED AT 250 WORDS)