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Measuring progression and regression of coronary atherosclerosis in clinical trials: problems and progress
1Department of Radiology, University of Montreal Medical School, Quebec, Canada.
Insights
Quantitative coronary arteriography is essential for clinical trials evaluating coronary atherosclerosis interventions. Two systems, CAAS and CMS, show reliable measurements, with CMS tracking arterial edges more precisely.
Area of Science:
- Cardiovascular research
- Medical imaging analysis
Background:
- Clinical trials for coronary atherosclerosis often use coronary events as endpoints, which is time-consuming.
- Quantitative coronary arteriography (QCA) offers a more efficient method using precise measurements of coronary artery dimensions.
Purpose of the Study:
- To assess the variability of two quantitative coronary arteriography systems: Cardiovascular Angiographic Analysis System (CAAS) and Cardiovascular Measurement System (CMS).
- To determine the reliability of these systems for measuring changes in coronary artery dimensions in clinical trials.
Main Methods:
- Variability of CAAS and CMS was tested on 54 lesions under four conditions, ranging from optimal to realistic clinical settings (different films, varying time intervals).
- Measurements of minimum diameter were analyzed for reproducibility and differences between systems.
Main Results:
- Repeat measurement variability increased with less optimal conditions for both CAAS (0.088 mm to 0.197 mm) and CMS (0.087 mm to 0.240 mm).
- No statistically significant differences were found between CAAS and CMS in minimum diameter measurements.
- CMS demonstrated more meticulous tracking of the arterial edge compared to CAAS.
Conclusions:
- Quantitative coronary arteriography is a crucial tool for clinical trials assessing interventions on coronary atherosclerosis.
- A change of ≥0.4 mm (CAAS) or ≥0.48 mm (CMS) in minimum diameter indicates a true progression or regression with >95% probability.
Abstract:
Interventions that may influence the evolution of coronary atherosclerosis can be evaluated more rapidly and efficiently in clinical trials with angiographic endpoints as opposed to using coronary events as endpoints. Quantitative coronary arteriography provides precise and reproducible measurements of coronary artery dimensions for this purpose. The variability of 2 quantitative systems was assessed in 54 lesions under 4 different conditions: same film, same frame; same film, same view; different frame; same view from different films obtained within one month; and same view from different films obtained one to 6 months apart. With the Cardiovascular Angiographic Analysis System (CAAS), variability of repeat measurement of minimum diameter, expressed as 1 standard deviation of the mean, increased from 0.088 mm (same frame) to 0.197 mm (films 1 to 6 months apart) as conditions decreased from optimal to those encountered in clinical studies. With the Cardiovascular Measurement System (CMS), 1 standard deviation for repeat measurements of minimum diameter increased from 0.087 mm (same frame to 0.240 mm (films one to 6 months apart). The differences between the two systems for measurements of minimum diameter were not statistically significant and CMS tracked the arterial edge more meticulously than did CAAS. A change in minimum diameter greater than or equal to 0.4 mm for CAAS or greater than or equal to 0.48 mm for CMS is more than 2 standard deviations of the mid-term variability and therefore represents a true change, either progression or regression, with greater than 95% probability. Quantitative coronary arteriography is an essential tool in clinical trials to assess the effect of an intervention upon the evolution of coronary atherosclerosis.(ABSTRACT TRUNCATED AT 250 WORDS)