Working Diagnosis:
Atherosclerotic coronary artery disease (CAD) with non-ST-elevation myocardial infarction secondary to ruptured plaque

Treatment:
The patient underwent successful stenting of his mid-LAD lesion. Liver ultrasound was negative. Gastroenterology was consulted and concluded that his transaminitis was likely due to transient hypotension and ischemic hepatopathy. Liver function tests began to resolve on hospital day 4. He was discharged on aspirin, clopidogrel, and atorvastatin. Beta blockers were held due to the patient's resting bradycardia.

Outcome:
The patient was seen by cardiology at one week and again at one month following his hospitalization. His transaminitis was fully resolved. Routine exercise stress test at one month was normal, and he was cleared to return to low-level aerobic exercise. At his three-month follow-up visit, he remained asymptomatic and was cleared to resume full training while continuing dual antiplatelet and statin therapy for three years. He was seen in the sports medicine clinic for cardiopulmonary exercise testing ten months after his hospitalization at which time he was doing well, and he was back to his usual training load though he had not returned to competition.

Author's Comments:
While regular aerobic exercise provides numerous cardioprotective benefits, a growing body of evidence sheds light on potential cardiac complications of long-term endurance training. Cardiac remodeling can predispose athletes to conditions such as atrial fibrillation and arrhythmogenic right ventricular cardiomyopathy. Additionally, several studies have demonstrated paradoxically high levels of coronary calcification in long-term endurance athletes, often at a higher-than-expected rate compared to age- and gender-matched peers. The pathophysiology leading to this finding is unclear; an increase in turbulent blood flow may play a role.

The risk of adverse cardiac events posed by this calcification is also unclear. It does not appear that unexpected coronary calcification in otherwise healthy endurance athletes carries the same risk of mortality or serious cardiac events compared to the general population. This may be due to an adaptive dilation of the coronary arteries in response to long-term aerobic training. There is also some speculation that the atherosclerosis seen in endurance athletes, being more highly calcified, is smoother and more stable than that seen in their sedentary counterparts. As in this patient, most adverse cardiac events due to atherosclerosis are seen following plaque rupture with resulting occlusion of a stenotic vessel. Whether endurance athletes have plaque that is less vulnerable to rupture remains uncertain.

Given their training loads, routine stress testing is unlikely to identify quiescent coronary artery disease in otherwise healthy endurance athletes. Furthermore, while numerous cardiomyopathies and channelopathies have been implicated in cardiac events among young athletes, coronary atherosclerosis remains the most common cause of sudden cardiac death in athletes over the age of 35. Physicians should remain vigilant for CAD in these patients, particularly those with genetic risk factors. Coronary artery CT calcium scores are a valuable tool in the evaluation and risk stratification of these athletes.

Editor's Comments:
This case of near syncope highlights an atypical presentation of acute coronary syndrome (ACS) in the absence of classic anginal symptoms such as chest pain or dyspnea. Recognizing that cardiac troponin elevations may occur in relation to exercise and are not necessarily associated with CAD or ACS, it is noteworthy that this patient was found to have plaque rupture.

The author raises some important points regarding cardiovascular adaptations to exercise, and this case presentation further illustrates the complex relationship between endurance training, CAD, and adverse cardiac events. While cardiovascular screening may be challenging in the relatively young but aging athlete, vigilance is indeed important and an individualized approach to risk stratification is warranted.

References:
Jafar O., Friedman J., Bogdanovicz I., et al. Assessment of coronary atherosclerosis using calcium scores in short and long distance runners. Mayo Clin Proc Innov Qual Outcomes. 2019;3(2):116–121.

Lavie CJ, Hecht HF, Wisloff U. Extreme Physical Activity May Increase Coronary Calcification, But Fitness Still Prevails. Mayo Clin Proc Innov Qual Outcomes. 2019 May 27;3(2):103-105.

Lee J., Patte R., Lavie C., Blair S.N. Running and all-cause mortality risk: is more better? Med Sci Sports Exerc. 2012;44(6):990–994.

Merghani A., Alfakin K., Patel K., et al. Prevalence of subclinical coronary artery disease in masters endurance athletes with a low atherosclerotic risk profile. Circulation. 2017;136:126–137.

O’Keefe J.H., Patil H.R., Lavie C.J., Magalski A., Vogel R.A., McCullough P.A. Potential adverse cardiovascular effects from excessive endurance exercise. Mayo Clin Proc. 2012;87(6):587–595.

Schnor P., O’Keefe J.H., Marott J.L., Lange P., Jensen G.B. Dose of jogging and long-term mortality: the Copenhagen City Heart Study. J Am Coll Cardiol. 2015;65(5):411–419.

Wen C.P., Wai J.P., Tsai M.K., et al. Minimum amount of physical activity for reduced mortality and extended life expectancy: a prospective cohort study. Lancet. 2011;378(9798):1244–1253.

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