Lipid lowering by simvastatin induces regression of human atherosclerotic lesions: two years' follow-up by high-resolution noninvasive magnetic resonance imaging.

Background: Statins are widely used to treat hypercholesterolemia and atherosclerotic disease. Noninvasive MRI allows serial monitoring of atherosclerotic plaque size changes. Our aim was to investigate the effects of lipid lowering with simvastatin on atherosclerotic lesions.
Methods and Results: A total of 44 aortic and 32 carotid artery plaques were detected in 21 asymptomatic hypercholesterolemic patients at baseline. The effects of statin on these atherosclerotic lesions were evaluated as changes versus baseline in lumen area (LA), vessel wall thickness (VWT), and vessel wall area (VWA) by MRI. Maximal reduction of plasma total and LDL cholesterol by simvastatin (23% and 38% respectively; P<0.01 versus baseline) was achieved after approximately 6 weeks of therapy and maintained thereafter throughout the study. Significant (P<0.01) reductions in maximal VWT and VWA at 12 months (10% and 11% for aortic and 8% and 11% for carotid plaques, respectively), without changes in LA, have been reported. Further decreases in VWT and VWA ranging from 12% to 20% were observed at 18 and 24 months. A slight but significant increase (ranging from 4% to 6%) in LA was seen in both carotid and aortic lesions at these later time points.
Conclusion: The present study demonstrates that maintained lipid-lowering therapy with simvastatin is associated with significant regression of established atherosclerotic lesions in humans. Our observations indicate that lipid-lowering therapy is associated with sustained vascular remodeling and emphasize the need for longer-term treatment.