Case Reports of the Athletic Heart
Athletes with Coronary Artery Calcifications: A Case Report
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.References
1. Physical Activity Guidelines Advisory Committee. 2018 Physical Activity Guidelines Advisory Committee Scientific Report. Washington, DC: U.S. Department of Health and Human Services; 2018.2. 2019 ACC/AHA guideline on the Primary Prevention of Cardiovascular Disease: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. J Am Coll Cardiol 2019;140(11): e596-e646.
3. Budoff MJ, Achenbach S, Blumenthal RS, et al. Assessment of coronary artery disease by cardiac computed tomography: a scientific statement from the American Heart Association Committee on Cardiovascular Imaging and Intervention, Council on Cardiovascular Radiology and Intervention, and Committee on Cardiac Imaging, Council on Clinical Cardiology. Circulation. 2006;114(16):1761-91.
4. Merghani A, Maestrini V, Rosmini S, et al. Prevalence of Subclinical Coronary Artery Disease in Masters Endurance Athletes With a Low Atherosclerotic Risk Profile. Circulation. 2017;136(2):126-137.
5. Aengevaeren VL, Mosterd A, Braber TL, et al. Relationship Between Lifelong Exercise Volume and Coronary Atherosclerosis in Athletes. Circulation. 2017;136(2):138-148.
6. Aengevaeren VL, Mosterd A, Sharma S, et al. Exercise and Coronary Atherosclerosis: Observations, Explanations, Relevance, and Clinical Management. Circulation. 2020;141(16):1338-1350.
7. Criqui MH, Knox JB, Denenberg JO, et al. Coronary Artery Calcium Volume and Density: Potential Interactions and Overall Predictive Value: The Multi-Ethnic Study of Atherosclerosis. JACC Cardiovasc Imaging. 2017;10(8):845-854.
8. Hou ZH, Lu B, Gao Y, et al. Prognostic value of coronary CT angiography and calcium score for major adverse cardiac events in outpatients. JACC Cardiovasc Imaging. 2012;5(10):990-9.
9. Peng AQ, Mirbolouk M, Orimoloye OA, et al. Long-Term All-Cause and Cause-Specific Mortality in Asymptomatic Patients with CAC ³ 1,000: Results from the CAC Consortium. JACC Cardiovasc Imaging. 2020;13(1 Pt 1):83-93.
10. Radford NB, Defina LF, Leonard D, et al. Cardiorespiratory Fitness, Coronary Artery Calcium, and Cardiovascular Disease Events in a Cohort of Generally Healthy Middle-Age Men: Results From the Cooper Center Longitudinal Study. Circulation. 2018;137(18)1888-1895.
11. Thompson PD, Myerburg RJ, Levine BD, Udelson JE, Kovacs RJ. Eligibility and Disqualification Recommendations for Competitive Athletes with Cardiovascular Abnormalities: Task Force 8: Coronary Artery Disease: A Scientific Statement from the American Heart Association and American College of Cardiology. Circulation. 2015;132(22):e310-4.
Authors: Deepak Ravi, MD;
Timothy Canan, MD, Division of Cardiology, Department of Medicine, University of California, Los Angeles
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