Relation of Coronary Artery Diameters With Cardiorespiratory Fitness
John S Ho1, John J Cannaday1, Shannon J FitzGerald2
1Cooper Clinic, Dallas, Texas.
Insights
Higher cardiorespiratory fitness is linked to larger coronary artery diameters, independent of traditional risk factors. This finding suggests a potential mechanism for how improved fitness protects against cardiovascular disease.
Area of Science:
- Cardiology
- Exercise Physiology
- Preventive Medicine
Background:
- Cardiorespiratory fitness is a known protective factor against cardiovascular morbidity and mortality.
- The precise mechanisms underlying this protective effect, beyond traditional risk factors, require further elucidation.
Purpose of the Study:
- To investigate the association between cardiorespiratory fitness and coronary artery diameters.
- To determine if higher fitness levels correlate with larger coronary artery sizes, independent of established cardiovascular risk factors.
Main Methods:
- Utilized gated multidetector computed tomography (CT) scans to measure proximal coronary artery diameters in 500 men.
- Assessed cardiorespiratory fitness using maximal exercise treadmill tests, reporting results in METs.
- Employed mixed-effects regression models to analyze the relationship between fitness and coronary artery dimensions, excluding individuals with coronary artery calcium scores ≥10.
Main Results:
- Higher cardiorespiratory fitness was significantly associated with larger diameters of the left main, left anterior descending, left circumflex, and right coronary arteries.
- Each one-unit increase in METs (a measure of fitness) correlated with a statistically significant increase in the diameter of all measured coronary arteries.
- The association between fitness and larger coronary artery diameters was particularly pronounced at fitness levels exceeding 10 METs.
Conclusions:
- Elevated cardiorespiratory fitness is independently associated with larger coronary artery diameters.
- This finding provides a potential anatomical explanation for the cardiovascular benefits observed in fitter individuals.
- Promoting higher levels of cardiorespiratory fitness may contribute to improved coronary artery health.
Abstract:
Cardiorespiratory fitness is associated with reduced cardiovascular morbidity and mortality when adjusted for traditional risk factors. Mechanisms by which fitness reduces risk have been studied but remain incompletely understood. We hypothesize that higher fitness is associated with larger coronary artery diameters independent of its effect on traditional risk factors. Two independent measurements of the proximal diameters of the left main, left anterior descending, left circumflex, and right coronary arteries were obtained from gated multidetector computed tomography scans in 500 men from the Cooper Center Longitudinal Study (CCLS). Men with coronary artery calcium scores ≥10 were excluded. Fitness was measured with a maximal exercise treadmill test and reported by quintiles and as a function of METs. We then evaluated the relation between coronary artery diameters and fitness using mixed effect regression models. Higher fitness was associated with larger coronary artery diameters after adjustment for body surface area, smoking status, low-density lipoprotein and high-density lipoprotein cholesterol, resting systolic blood pressure, and serum glucose. When examined continuously, each MET increase in fitness was associated with a mean 0.03 ± 0.01 mm larger diameter of the left main, a 0.04 ± 0.01 mm larger diameter of the left anterior descending, a 0.05 ± 0.01 mm larger diameter of the left circumflex, and a 0.07 ± 0.01 mm larger diameter of the right coronary artery (p = 0.002). This correlation between fitness and coronary artery diameters was most prominent for fitness levels above 10 METs. In conclusion, higher fitness is associated with larger coronary artery diameters.
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