Effects of lipid-lowering therapy on coronary artery remodeling

BACKGROUND: Although lipid-lowering therapy affects the luminal size of atherosclerotic coronary arteries the role of vascular remodeling has not been systematically studied. DESIGN/METHODS: Serial three-dimensional volumetric intravascular ultrasound (IVUS) was used to study remodeling, which was defined as changes in arterial size independent of or dependent on changes in plaque size. Using an automated contour detection algorithm, a 1 mm segment of a moderate atherosclerotic lesion at the site of the maximal plaque volume at baseline was analysed. After 12 months the relationship between the absolute change in vessel volume and plaque volume was calculated in 99 patients. There was a significant relationship between changes in plaque and vessel volume, independent of plaque progression or plaque regression (decrease in plaque size, r = 0.60, P < 0.0001 and increase in plaque size, r = 0.49, P < 0.0008, respectively; the slopes of the regression equation were 1.03 and 0.80). By means of an analysis of covariance we tested whether the regression slopes were equal between groups of patients as defined by the low-density lipoprotein-cholesterol (LDL-c) level achieved with lipid-lowering therapy. RESULTS: Only patients with plaque progression and a LDL-c level < 100 mg/dl had a significantly smaller slope than patients with a LDL-c level > 100 mg/dl (-0.14 compared with 1.14, P = 0.003 ), indicating diminished coronary remodeling. CONCLUSIONS: Serial volumetric IVUS confirms the existence of both positive and negative remodeling in relation to an increase and decrease in plaque volume. It has been shown that the outward remodeling process is diminished in patients with plaque progression and intensive lipid-lowering therapy.