Which angiographic variable best describes functional status 6 months after successful single-vessel coronary balloon angioplasty?

OBJECTIVES: The aim of this study was to determine which quantitative angiographic variable best describes functional status 6 months after coronary balloon angioplasty. BACKGROUND: Several angiographic restenosis criteria have been developed. These can be divided into those that describe the change in lesion severity and those that merely describe lesion severity at follow-up angiography. The functional significance of these criteria is unknown. METHODS: We studied 350 patients with single-vessel coronary artery disease who underwent a single-site balloon dilation. Sensitivity and specificity curves were constructed for the prediction of anginal status and exercise electrocardiography of four quantitative angiographic variables that describe restenosis. The point of highest diagnostic accuracy for the variables was determined at the intersection of the sensitivity and specificity curves. Results of exercise electrocardiography were considered indicative for ischemia 6 months after angioplasty if horizontal or downsloping ST segment depression > or = 1 mm occurred. RESULTS: The points of highest diagnostic accuracy of the angiographic variables were similar for both anginal status and exercise electrocardiography: 1.45 and 1.46 mm for the minimal lumen diameter measurements, 45.5% and 46.5% for the percent diameter stenosis measurements at follow-up, -0.30 and -0.32 mm for change in minimal lumen diameter and -10% and -10% for the change in percent diameter stenosis at follow-up. CONCLUSIONS: Angiographic variables reflecting a change in lesion severity at follow-up angiography were only slightly less accurate than variables that describe lesion severity at follow-up. The large study group and the fact that the same optimal values for diagnostic accuracy of the various quantitative angiographic variables were obtained for the prediction of two different markers of ischemia suggests that these values reflect the lesion severity or increase in lesion severity in major epicardial vessels at which coronary flow reserve is unable to meet myocardial demands.