Background: Prior studies have established the prognostic value of myocardial perfusion imaging. In particular, the presence and extent of transient defects have been shown to predict future cardiac events including acute myocardial infarction. However, the relationship between the location of the perfusion defect and the site of subsequent myocardial infarction remains unclear.
Methods and results: Review of prior records of consecutive patients admitted with acute myocardial infarction identified 34 patients whose prior myocardial perfusion imaging studies had demonstrated transient defects and no interval revascularization. The coronary artery territory of the transient defects was identified and related to the site of subsequent acute myocardial infarction. To reduce the potentially confounding effect of progression of coronary artery disease between the time of the myocardial perfusion imaging study and subsequent infarction, patients were divided into those less than 2 years and those 2 years or greater between imaging and infarction. Among patients with a transient defect and less than 2 years between infarction and imaging, 11 (79%) of 14 had a myocardial infarction in the same coronary territory as their prior transient defect (p < 0.0005). This association decreased to only five (25%) of 20 when the interval was 2 years or greater (difference not significant). Among 22 patients who had undergone prior coronary angiography, myocardial infarction occurred in the same coronary territory as the most severe angiographic stenosis in 12 (54%). The association was not related to the time interval between angiography and infarction.
Conclusions: There is a strong association between the coronary territory of transient defects on myocardial perfusion imaging and the site of subsequent myocardial infarction when the duration is less than 2 years. These observations support the concept that the hemodynamic significance of a coronary lesion is an important factor in the pathophysiology of acute myocardial infarction.