Abstract 2611: Effect of Lipid-Lowering Therapy with High and Low-dose Atorvastatin on Atherosclerotic Aortic Plaques: Two Years’ Follow-up by Noninvasive MRI
Using MRI, we recently reported plaque regression in thoracic aorta by 1-year (yr) 20-mg atorvastatin treatment. However, long-term effects of different doses of statin on plaques have not been assessed. We investigated the effects of 20-mg vs 5-mg atorvastatin on thoracic and abdominal aortic plaques in 36 hypercholesterolemic (LDL-C >150 mg/dl) patients who were randomized to either dose. Aortic MRI was performed at baseline (0 yr) and 1 yr and 2 yrs of treatment. Total of 45 thoracic and 63 abdominal plaques were followed up. Treatment effects were assessed as changes in vessel wall area (VWA) of such lesions from 0 to 1 yr and those from 1 to 2 yrs of treatment.
RESULTS: The 20-mg dose markedly reduced LDL-C levels (from 200±47 to 107±34 mg/dl; −47%) vs 5−mg dose (from 195±35 to 129±32 mg/dl; −35%)(P<0.001). The 20-mg and 5-mg doses also reduced CRP levels by 47% and 23%. In thoracic plaques, 20-mg dose induced plaque regression (−14% VWA reduction, P<0.001) from 0 to 1 yr of treatment, but no further regression (−1%) was found from 1 to 2 yrs. In contrast, 5-mg dose progressively increased VWA by +3% from 0 to 1 yr and by +4% from 1 to 2 yrs (P<0.05). Notably, VWA change in thoracic plaques from 0 to 1 yr correlated with the degrees of LDL-C reduction (r=0.61) and CRP reduction (r=0.50), whereas VWA change from 1 to 2 yr correlated with LDL-C levels achieved after treatment (r=0.64). Maintaining LDL-C levels <110 mg/dl was needed to prevent plaque progression after 1 yr of treatment. In abdominal plaques, no VWA changes were found from 0 to 1 yr and from 1 to 2 yrs of 20-mg treatment (+2% and 0%), whereas 5-mg dose progressively increased VWA by +8% from 0 to 1 yr and by +2% from 1 to 2 yrs (P<0.005). Although VWA change in abdominal plaques from 0 to 1 yr weakly correlated with the degree of LDL-C reduction (r=0.30), it also correlated with age (r=0.30). No correlation between VWA change from 1 to 2 yrs and LDL-C levels was found.
CONCLUSION: One-yr 20-mg atorvastatin treatment induced plaque regression in thoracic aorta with marked LDL-C reduction. After 1 yr of treatment, no further regression was found, and maintaining low LDL-C levels was needed to prevent plaque progression. However, in abdominal aorta, atorvastatin resulted in only retardation of plaque progression, even after 2 yrs of treatment.