The Carotid Atherosclerosis Italian Ultrasound study (CAIUS), a multicenter, double-blind
clinical trial, performed in 305 asymptomatic, moderately hypercholesterolemic patients,
clearly demonstrated beneficial effects of pravastatin on the carotid intima-media
thickness (IMT) progression. The database of the CAIUS study was examined in order
to investigate the presence of a relationship, if any, between the activity of pravastatin
on IMT progression rate and its hypocholesterolemic effect. Quantitative B-mode ultrasound
imaging was used to quantify the individual mean maximum IMT progression rate in 3
years. In the overall group of patients (placebo and pravastatin) covariance analysis
showed that while the variable 'treatment' (0 = placebo, 1 = pravastatin) was significantly
related to the reduction of IMT progression (F= 6.6, P = 0.01), the IMT progression
did not correlate with the extent of LDL-C lowering (F= 0.00, P = 0.98). To further
investigate this issue. the pravastatin treated group was stratified into quartiles
of LDL-C reduction. In contrast to what was observed in the placebo group, in which
a positive mean IMT progression rate was observed, independent of the extent of LDL-C
reduction, no IMT progressionwas observed in any subgroup treated with pravastatin.
No significant difference was found among quartiles and no trend could be identified.
In conclusion, the effect of pravastatin treatment on carotid IMT progression rate
is beneficial; however the CAIUS study demonstrated that lowering LDL-C by itself,
does not explain the variability of beneficial changes in IMT.