Athletes with Coronary Artery Calciﬁcations: A Case Report
Authors: Deepak Ravi, MD; Timothy Canan, MD, Division of Cardiology, Department of Medicine, University of California, Los Angeles
Discussion The development of computed tomographic protocols to study coronary artery disease has provided useful tools to assess cardiovascular risk, although the interpretation of ﬁndings in athletes compared to sedentary individuals has become an area of increasing interest. In particular, the coronary artery calciﬁcation score (CACS), expressed in Agatston units, has been shown to be predictive of future cardiovascular events.3,4 The CACS is calculated as the product of coronary artery calciﬁcation (CAC) volume and density as evaluated by non-contrast CT. Interestingly, several studies have demonstrated an increased prevalence of CACS >100 in active subjects. In a study of 244 men with low 10-year Framingham coronary risk scores, Merghani, et al found an increased prevalence of CACS >300 Agatston units amongst athletes with elevated CACS compared to sedentary males.4 Similarly, Angevaeran, et al demonstrated a signiﬁcantly elevated CACS among athletes who reported lifelong high-volume vigorous exercise in comparison to those reporting low volumes of exercise.5 Reconciling these seemingly paradoxical results has been an area of ongoing research.
Several factors may underlie the ﬁndings of increased coronary calcium scores amongst athletes. Evaluation of coronary plaque using CT coronary angiography allows for morphologic characterization of atherosclerotic disease. Calciﬁed plaques are thought to confer the lowest risk of resulting in cardiovascular events, while mixed plaques are associated with the highest risk; non-calciﬁed plaques carry intermediate risk4. As such, plaque identiﬁed in male athletes have been found to be mostly calciﬁc in nature, whereas mixed morphology plaque is more commonly identiﬁed in sedentary males4,6. Moreover, the Agatston unit is calculated as the product of plaque density and volume. While plaque volume is associated with increased cardiovascular disease, plaque density is inversely correlated with cardiovascular disease.5 Thus, calciﬁc plaque identiﬁed among athletes may represent lower risk disease than the lipid-rich, mixed plaque prevalent amongst sedentary individuals. Moreover, there is large variability in the reported prevalence of CACS. In a review article, Angevarean, et al, reported CAC prevalence of 34 to 71% amongst athletic cohorts.6 As above, Merghani et al’s ﬁndings suggest that while most endurance athletes with a low risk CV proﬁle at baseline have normal CAC scores, those predisposed to coronary calciﬁcations may carry a greater burden of disease.5 Finally, given the relatively homogenous nature of study populations, more research investigating the qualitative and quantitative burden of disease amongst gender speciﬁc and race speciﬁc populations is required, as well as among non-endurance athletes. Evidence informing the management of the athlete with an elevated coronary artery calcium score is sparse and necessitates further research. While athletes with elevated CACS tend to have lower risk plaque morphology, it is well established that individuals with an elevated CACS carry signiﬁcantly increased risk of major cardiac events in comparison with those with a CACS of 0. CACS >400 is associated with an estimated 34% risk of MACE, compared with 2.1% for CACS of 0.8 Individuals with CACS >1000 in particular appear to represent very high risk of CVD and all cause mortality.9 Thus, athletes with signiﬁcant atherosclerotic disease should be managed aggressively with statin and antiplatelet therapy as appropriate, even though their true risk proﬁle may be somewhat different from the general population. However, increased levels of cardiorespiratory ﬁtness have been linked to lower rates of cardiovascular disease, even in the setting of elevated CAC scores. Radford, et al found an 11% decrease in risk of CVD events for each additional MET of ﬁtness in all CAC groups, establishing the beneﬁcial effect of exercise in preventing cardiovascular disease in patients with elevated CACS.10. Individuals with signiﬁcantly elevated CACS, such as the patient from our case, would likely beneﬁt from maximal exercise testing to evaluate for inducible ischemia or electrical instability, as well as evaluation of left ventricular function, in keeping with the AHA/ACC recommendations for competitive athletes.11 Moreover, in patients such as ours with very elevated CACS, a secondary prevention strategy with antiplatelet therapy daily or periodically prior to races may be appropriate if not at increased bleeding risk. While more research is warranted to fully elucidate the optimal management of asymptomatic individuals with very high CACS, it is reasonable to pursue the most aggressive preventative strategies regardless of physical activity level.
Take home message
CACS is a useful tool in evaluating cardiovascular disease risk. While physical activity is associated with an improved cardiovascular risk proﬁle, athletes have also been found to have elevated CACS. Although the clinical implications of these ﬁndings are unclear, management of the athlete with an elevated CACS should take into account individual risk factors and the patient’s preferences. Those with a signiﬁcantly elevated risk proﬁle should undergo aggressive guideline-based risk mitigation.
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