Effect of lipid-lowering therapy with atorvastatin on atherosclerotic aortic plaques: a 2-year follow-up by noninvasive MRI.

BACKGROUND: Using MRI, we reported plaque regression in thoracic aorta and retardation of plaque progression in abdominal aorta by 1-year atorvastatin. However, association between serial plaque changes and LDL-cholesterol levels was not fully elucidated.

DESIGN: A prospective, randomized, open-label trial.

METHODS: We investigated the long-term effect of 20 versus 5-mg atorvastatin on thoracic and abdominal plaques and the association between plaque progression and on-treatment LDL-cholesterol levels in 36 hypercholesterolemic patients. MRI was performed at baseline and 1 and 2 years of treatment. Vessel wall area change was evaluated.

RESULTS: The 20-mg dose markedly reduced LDL-cholesterol levels (-47%) versus 5-mg (-35%) dose. After 2 years of treatment, regression of thoracic plaques was found in the 20-mg group (-15% vessel wall area reduction), but not in the 5-mg group (+7%). Although the 20-mg dose induced plaque regression (-14%) from baseline to 1 year, no further regression was seen from 1 to 2 years of treatment (-1%). Regarding abdominal plaques, progression was found in the 5-mg group (+10%), but not in the 20-mg group (+2%). Plaque progression in the 5-mg group was found from baseline to 1 year (+8%), but not from 1 to 2 years (+2%). The degree of thoracic plaque regression correlated with LDL-cholesterol reduction (r = 0.61), whereas thoracic plaque change from 1 to 2 years correlated with on-treatment LDL-cholesterol levels (r = 0.64).

CONCLUSION: Twenty milligrams of atorvastatin regressed thoracic plaques. However, maintaining low LDL-cholesterol levels was needed to prevent plaque progression. In abdominal aorta, only retardation of plaque progression was found after 2 years of 20-mg treatment.