Relation of Coronary Artery Diameters With Cardiorespiratory Fitness.

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.

Low 25-OH vitamin D levels are not associated with coronary artery calcium or obstructive stenoses.

BACKGROUND: It is unclear whether low vitamin D is a significant risk factor for the presence of either calcific atherosclerosis or obstructive coronary artery stenoses. DESIGN: In this study, we measured the 25-OH vitamin D levels of 1131 consecutive individuals who underwent coronary artery calcium (CAC) scoring and coronary computed tomographic angiography at our institution. PARTICIPANTS AND METHODS: We looked for any association of 25-OH vitamin D levels with CAC scores. We also studied the relation of 25-OH vitamin D levels with the presence of 70% or more obstructive coronary artery stenoses, found initially by coronary computed tomographic angiography and confirmed subsequently by invasive angiography. RESULTS: There were 132 (11.7%) 25-OH vitamin D deficient (<20 ng/ml) and 295 (26.1%) 25-OH vitamin D insufficient (21-29 ng/ml) individuals in this study. There was no detectable association between 25-OH vitamin D levels and CAC scores. The median (interquartile range) CAC score of 25-OH vitamin D deficient, insufficient, and adequate patients was 451 (80-1083), 338 (52-830), and 450 (100-1062), respectively. Also, no relation was noted between 25-OH vitamin D levels and the presence of severely obstructive coronary artery disease. The frequency of severe coronary artery disease in 25-OH vitamin D deficient, insufficient, and adequate patients was 3.8, 2.0, and 4.0%, respectively. CONCLUSION: Low 25-OH vitamin D levels were not associated with CAC or severely obstructive stenoses.

Utility of high-sensitivity C-reactive protein versus coronary artery calcium for the detection of obstructive stenoses in stable patients.

The inflammatory biomarker high-sensitivity C-reactive protein (hs-CRP) has emerged as a predictor of future cardiovascular events. Screening for coronary artery calcium (CAC) is an alternative method for stratifying subjects by their cardiovascular risk. It is unclear, however, how hs-CRP compares with CAC scoring for the detection of obstructive coronary artery stenoses. We, thus, evaluated the association, if any, between hs-CRP and CAC scores for the detection of obstructive stenoses in a low-risk population with well-controlled traditional cardiovascular risk factors. In the present study of 1,079 stable subjects, 38 (3.5%) severely obstructive stenoses were found initially by coronary computed tomographic angiography and confirmed subsequently using invasive coronary angiography. The univariate predictors of severely obstructive coronary artery disease included the use of antihypertensive agents (p = 0.03), angina (p <0.001), and an elevated CAC score (p <0.001). The biomarker hs-CRP was not significantly associated with the presence of a severely obstructive stenosis. As the CAC scores increased, the frequency of obstructive stenosis also increased (p for trend <0.001). In contrast, the frequency of obstructive stenoses was low when CAC was not detected. This relation remained significant after adjustment for antihypertensive medication use and angina. In conclusion, hs-CRP was not useful for the prediction of obstructive stenoses in stable subjects. CAC was found to be a better predictor of obstructive heart disease than hs-CRP.