Quantitative angiographic morphology of the coronary artery lesions at risk of thrombotic occlusion.

BACKGROUND: Coronary angiography in acute myocardial infarction has revealed complicated atherosclerotic plaque and a high rate of thrombotic occlusion. However, the characteristics of lesions at high risk of subsequent occlusion are not well known. METHODS AND RESULTS: In the present study, the qualitative and quantitative angiographic features of 38 coronary artery lesions that occluded within 3 years to cause an acute myocardial infarction were compared with 64 control segments from the same patients that did not occlude. Compared with control lesions, the lesions that occluded were more likely to have a division branch originating within the stenosis (76% versus 52%, p less than 0.05). The percent lumen diameter reduction was more severe (47.5 +/- 17.8% versus 41 +/- 12.5%, p less than 0.05) and the inflow (21 +/- 10 degrees versus 16 +/- 7 degrees, p less than 0.05) and outflow (20 +/- 10 degrees versus 16 +/- 8 degrees, p less than 0.05) angles of the stenosis were steeper. Time to myocardial infarction after the angiogram interacted with the importance of these features (p less than 0.02). Thus, paired analysis of the lesions that occluded within 3 months and of the most severe control lesion from each patient showed percent lumen diameter reduction of 62.1 +/- 11.5% and 46.4 +/- 11.4%, respectively (p less than 0.001). The length of the stenosis, its asymmetry, and the irregularity of the contours did not help differentiate occlusive from control segments. CONCLUSIONS: Coronary artery lesions at high risk of thrombotic occlusion share common characteristics that favor higher shear stress and flow separation.