Rationale, Design and Baseline Characteristics of a Clinical Trial Comparing the Effects of Robust vs Conventional...

Hypercholesterolaemia is strongly associated with increased vessel wall thickness as measured by ultrasound. The question is whether aggressive cholesterol lowering with high-dose atorvastatin can alter intima media thickening to a greater extent than conventional therapy in patients with familial hypercholesterolaemia (FH). The baseline characteristics of a double-blind, randomised trial are described to determine whether two active treatments (high-dose atorvastatin 80mg versus conventional dose simvastatin 40mg), administered over a period of 2 years, may retard the process of intima media thickening in the carotid and femoral arteries of patients with FH.

325 patients with FH were randomised. Patients entered an 8-week placebo period in which all lipid-lowering medication was discontinued. Thereafter, baseline measurements of lipoprotein parameters and intima media thickness (IMT) of carotid and femoral artery were performed.

Baseline low density lipoprotein (LDL) cholesterol (±SD) levels were 8.11 ± 1.92 mmol/L (312 ± 73 mg/dl) in men and 8.22 ± 1.91 mmol/L (316 ± 73 mg/dl) in women, respectively. Mean posterior wall IMT in the left common carotid artery (CCA) was significantly greater in men (0.94 ± 0.29mm) compared with women (0.85 ± 0.20) [p < 0.05]. A similar difference was found for the internal carotid artery (ICA). In the carotid bifurcation, IMT was 1.20 ± 0.50mm in men and 1.1 ± 0.54mm in women. The IMT of the common femoral artery (CFA) was 2.03 ± 0.88mm in men with cardiovascular disease (CVD) and 1.63 ± 0.70mm in men without CVD (p < 0.05). Strikingly, plaques were present in all men and 95% of the women with CVD. The cholesterol-year score and HDL cholesterol levels partially explained the variation in IMT in the carotid bifurcation, whereas gender and smoking contributed to the variation in IMT in the CFA in this group of patients.

The patients participating in the Atorvastatin and Simvastatin on Atherosclerosis Progression (ASAP) trial constitute the largest well-documented FH population exhibiting marked increases in IMT of both carotid and femoral arteries and a very high prevalence of plaques, indicating extreme CVD risk. Since lipid-lowering therapy provides the highest benefit in precisely such patients, the ASAP trial will help assess whether aggressive LDL cholesterol intervention leads to retardation of subclinical atherosclerosis progression, as estimated with ultrasonographically assessed IMT.