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Efficacy of two lipid-lowering treatments on quantitative coronary angiographic endpoints
W J Mack1, M Xiang, A M Shircore
1Department of Preventive Medicine, University of Southern California Keck School of Medicine, Los Angeles 90089-9010, USA.
Abstract:
This study contrasts the sensitivity of four quantitative coronary angiography (QCA) measures (percent diameter stenosis [%S], minimum lumen diameter, average segment diameter, and percent involvement) in detecting 2-year treatment effects of two lipid-lowering therapies and reports on the longitudinal pattern after 4 years of treatment on the primary QCA trial endpoint (%S) for all, mild/moderate (<50%S), and severe lesions (> or =50%S). Patient cohorts were followed up from two randomized, placebo-controlled clinical trials of lipid-lowering therapies-colestipol/niacin in the Cholesterol Lowering Atherosclerosis Study (CLAS) and lovastatin in the Monitored Atherosclerosis Regression Study (MARS). Identical QCA methodology was used. In CLAS, the largest 2-year treatment effect size (=0.60) was noted for %S. In MARS, equivalent 2-year effect sizes (=0.15) were noted for three QCA measures. The largest 2-year effect size in %S was found in CLAS for mild/moderate lesions (=0.55) and in MARS for severe lesions (=0.31). Treatment in CLAS led to regression of disease in the first 2 years; treatment in MARS slowed progression of disease in the first 2 years and led to regression of disease after 4 years. Colestipol/niacin reduced progression of mild/moderate and severe lesions over the first 2 years of therapy; lovastatin reduced the progression of severe lesions over the last 2 years of therapy. We conclude that reducing the progression of atherosclerosis is not a simple proposition; maximal therapy for reducing and stabilizing atherosclerosis most likely will result from the selection of agents targeted at specific lesions.
Insights
This study compared quantitative coronary angiography measures for lipid-lowering therapies. Percent diameter stenosis (%S) effectively detected treatment effects on atherosclerosis progression over time.
Area of Science:
- Cardiovascular Medicine
- Pharmacology
- Medical Imaging
Background:
- Lipid-lowering therapies are crucial for managing atherosclerosis.
- Quantitative coronary angiography (QCA) is used to assess treatment efficacy.
- Understanding the sensitivity of different QCA measures is important for clinical trials.
Purpose of the Study:
- To contrast the sensitivity of four QCA measures in detecting 2-year treatment effects of lipid-lowering therapies.
- To report on the longitudinal pattern of atherosclerosis progression over 4 years of treatment.
- To analyze treatment effects on mild/moderate and severe coronary lesions.
Main Methods:
- Analysis of patient cohorts from two randomized, placebo-controlled trials (CLAS and MARS).
- Utilized identical quantitative coronary angiography (QCA) methodology.
- Compared percent diameter stenosis (%S), minimum lumen diameter, average segment diameter, and percent involvement.
Main Results:
- Percent diameter stenosis (%S) showed the largest 2-year treatment effect size in the CLAS trial (=0.60).
- In MARS, three QCA measures had equivalent 2-year effect sizes (=0.15).
- %S demonstrated the largest 2-year effect size for mild/moderate lesions in CLAS (=0.55) and severe lesions in MARS (=0.31).
- Colestipol/niacin reduced lesion progression in both mild/moderate and severe lesions over 2 years.
- Lovastatin slowed disease progression in the first 2 years and induced regression after 4 years, particularly in severe lesions.
Conclusions:
- Reducing atherosclerosis progression is complex and depends on lesion type.
- Maximal therapy likely involves agents targeted at specific lesion types.
- %S is a sensitive measure for detecting treatment effects in lipid-lowering trials.