Masters Endurance Athletes and Subclinical CAD
What is the prevalence of coronary artery disease (CAD) in masters endurance athletes with a low atherosclerotic risk profile?
A cohort of 152 masters athletes 54.4 ± 8.5 years of age (70% male) and 92 controls of similar age, sex, and low Framingham 10-year CAD risk scores were assessed with an echocardiogram, exercise stress test, computerized tomographic coronary angiogram (CTA) with coronary artery calcium (CAC) assessment, cardiovascular magnetic resonance imaging with late gadolinium enhancement, and 24-hour Holter. Athletes had participated in endurance exercise for an average of 31 ± 12.6 years. The majority (77%) were runners, with a median of 13 marathon runs per athlete.
Most athletes (60%) and controls (63%) had a normal CAC score. Compared with sedentary men, male athletes had a higher prevalence of atherosclerotic plaques of any severity (44.3% vs. 22.2%, p = 0.009), and only male athletes had a CAC ≥300 Agatston units (11.3%) and a luminal stenosis ≥50% (7.5%). Male athletes had predominantly calcific plaques (72.7%), whereas sedentary males had predominantly mixed morphology plaques (61.5%). Among male athletes, the number of years of training was the only independent variable associated with increased risk of CAC >70th percentile for age, or luminal stenosis ≥50% (odds ratio, 1.08; 95% confidence interval, 1.01-1.15; p = 0.016). Fifteen (14%) male athletes but none of the controls had late gadolinium enhancement on cardiovascular magnetic resonance imaging; of these athletes, seven had a pattern consistent with previous myocardial infarction, including three (42%) with a luminal stenosis ≥50% in the corresponding artery.
Most lifelong masters endurance athletes with a low atherosclerotic risk profile have normal CAC scores. However, compared with sedentary men with similar risk profiles, male athletes are more likely to have a CAC score >300 Agatston units or a coronary plaque; however, plaque composition in athletes was predominantly calcific. Although the significance of these observations is uncertain, the authors concluded that coronary plaques are more abundant in athletes, but their stable nature could mitigate the risk of plaque rupture and acute myocardial infarction.
Endurance exercise has been associated with higher levels of CAC. However, it is not clear that there is an associated increased risk of cardiac events. This study suggests that lifelong masters endurance athletes are more likely than sedentary men with similar risk profiles to have high CAC scores and evidence of coronary plaque on CTA. However, plaque composition in athletes was predominantly calcific, and the more stable plaque composition might not portend increased risk of cardiac events. Although higher levels of coronary calcium in a general population might be associated with increased cardiovascular risk, these data (along with data from another article in the same issue [doi: 10.1161/CIRCULATIONAHA.117.027834]) suggest that the CAC versus cardiovascular risk relationship might be different among athletes.
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