Effect of Lipid-lowering Treatment on Progression of Atherosclerotic Lesions--a Duplex Ultrasonographic Investigation

The Prevenzione Aterosclerosi Studio Torino (P.A.S.T.) was a prospective, randomized trial testing the effect on carotid and femoral atherosclerotic lesions of lipid-lowering therapy, as assessed by duplex scanning (DS) technique, in 85 patients (12 women, 73 men), forty-five to fifty-five years old, with ischemic heart disease (IHD), and randomly assigned to a hypolipidemic diet or diet + 250 mg acipimox (a nicotinic acid compound) two to three times/day. Forty-one patients, without inclusion criteria, were compared with the randomized groups as a reference population. All three groups were submitted to DS and to hematic monitoring of lipid levels at the beginning and at the end of the study. During three years of treatment, there was a significant reduction (-6.5%) in total plasma cholesterol in the diet + drug group (P = 0.04) and a simultaneous elevation of high-density lipoprotein cholesterol, significant in the treatment groups (respectively, +15% P = 0.02 in the diet and +16% P = 0.016 in the diet + drug group). Every group showed a trend toward the increasing number of lesions in all explored areas and toward the progression in size of the already existing ones. Whereas in the initial DS the prevalence of lesions was significantly lower in the nonrandomized group in every site, at the end of the study the total number of lesions did not differ among groups, and there was a significant increase of plaques in carotid area in the nonrandomized group in comparison with the treatment groups. The final number of stable plaques was greater in the treatment groups as compared with the nonrandomized group (P = 0.01 diet vs nonrandomized, P = 0.03 diet + drug vs nonrandomized). In conclusion, lipid-lowering treatment, with diet and with diet + drug, was useful in slowing the natural progression of atherosclerosis; particularly, it reduced the development of new lesions in the carotid and femoral arteries and increased the stability of the already existing ones. In these patients, diet was equivalent to diet + drug in regard to progression of lesions. The most favorable results in the treatment groups seem to correlate with high-density lipoprotein cholesterol, significantly increased in comparison with the nonrandomized group.