Early Atherosclerosis Change in Two Clinical Trials
To complete end point analysis for the Monitored Atherosclerosis Regression Study (MARS) and to compare coronary versus carotid treatment effect relationships in MARS to coronary versus carotid treatment effect relationships in the Cholesterol Lowering Atherosclerosis Study (CLAS). Both MARS and CLAS were serial arterial imaging trials that explored the reversibility of atherosclerosis with lipid-lowering therapy in native coronary, carotid, and femoral arterial beds, as well as in coronary artery bypass grafts.
Carotid Artery Diseases
|Study Design:||Time Perspective: Retrospective|
|Study Start Date:||January 1994|
|Estimated Study Completion Date:||December 1996|
MARS was a randomized, double-blind, placebo-controlled, angiographic trial comparing the effects of lipid lowering by lovastatin and diet with diet plus placebo in 270 subjects. The target study population consisted of males and females under 70 years of age with cholesterol levels from 200 to 295 mg/dL and coronary artery disease in two or more coronary artery segments. Follow-up coronary angiograms were performed two and four years post-randomization in 247 and 68 subjects, respectively; providing information on atherosclerosis regression/progression of coronary artery intrusive lesions. Carotid ultrasound images have been recorded at four month intervals for periods up to four years in 215 subjects providing information on atherosclerosis regression/progression of pre-intrusive (intima-media thickness) lesions in parallel with coronary artery intrusive lesions. Unique features of MARS included: 1) Simultaneous coronary angiography (evaluated both by quantitative coronary angiography (QCA) and panel-reading) and carotid ultrasonography in a cohort of over 200 subjects; 2) The opportunity to evaluate the largest lipoprotein and apolipoprotein data collected in an angiographic trial to date. This included extensive VLDL, LDL, IDL, and HDL subclasses as well as LDL type pattern, lipoprotein particles and apolipoprotein (including AI, B, CIII, and E); and, 3) The opportunity to evaluate dietary effects on atherosclerosis regression/progression only in one other angiographic trail, CLAS.
The Cholesterol Lowering Atherosclerosis Study (CLAS) was a randomized angiographic trial comparing combined colestipol/niacin therapy with placebo in 162 subjects. A unique feature of MARS and CLAS has shown a similar effect in CLAS-like men (non-smoking men with CABG) and women. Since carotid intima-media thickness, QCA, and global change score have been shown to be predictive of clinical coronary events, understanding the relationship between these atherosclerotic measures may be important in establishing carotid intima-media thickness measurements as a proxy measure for coronary atherosclerosis.
Collected data for both trials were analyzed and compared to evaluate effects of treatment on carotid and coronary artery atherosclerotic lesions. Coronary angiograms and carotid ultrasound imaging were performed under identical conditions in both trials. Five major databases were available for analysis, including: the coronary artery database (QCA processed); the carotid artery database (ultrasound evaluation); the coronary artery database (panel evaluation); the nutrient content database, and the clinical and biochemical database. Major comparisons included measurements of atherosclerotic lesions in both arteries, the effects of lipid, lipoprotein, and apolipoprotein levels on vascular lesions, and the effect of nutrient intake (in particular total fat, saturated fat, and cholesterol) on rates of measured lesion change. Additional associations were sought between preintrusive carotid lesions and intrusive coronary lesions between males and females, smokers and nonsmokers, differences in age, and differential drug effect on HDL-cholesterol.
|Investigator:||Howard Hodis||University of Southern California|