Background: Measurement of intima-media thickness (IMT) is a well established surrogate marker for cardiovascular endpoints. We studied the long-term effects of statins on femoral IMT and plaque scoring in the Atorvastatin versus Simvastatin on Atherosclerosis Progression (ASAP) study.
Methods and results: Three hundred and twenty-five patients with familial hypercholesterolaemia were randomized to either atorvastatin 80 mg/day or simvastatin 40 mg/day. IMT was measured at baseline and at 2 years. At baseline, femoral IMT was 1.69 mm in the atorvastatin group and 1.61 mm in the simvastatin group; at 2 years, IMT increased by 0.06 mm (P=0.24) and 0.15 mm (P=0.012), respectively. No significant differences were obvious between these two treatment arms (P=0.26). Femoral plaques were present in 64.7% in the atorvastatin group and 56.1% in the simvastatin group at baseline; after 2 years, these proportions rose to 66.0% (P=0.47) and 67.3% (P=0.02), respectively (P=0.87 between treatment arms). Carotid plaques were present in 6.3% versus 4.9%; after 2 years, these percentages were 5.0% (P=0.48) versus 5.5% (P=0.71), respectively (P=0.90 between treatment arms).
Conclusion: Our study indicates increased efficacy of atorvastatin 80 mg in retarding progression of atherosclerosis in the femoral artery compared with simvastatin 40 mg. Interestingly, in the carotid arteries these statins influenced IMT to a greater extent, whereas in the femoral artery the effects were more pronounced on plaque frequency. These findings underscore the generalized effects of lipid lowering on atherosclerosis.