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Center for Coronary Artery Anomalies
The Center for Coronary Artery Anomalies at the Texas Heart Institute
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Sudden Cardiac Arrest
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Research at the Center for Coronary Artery Anomalies

For some 40 years, the medical literature has reported a worrisome association between competitive sports activities and CAA and related SCD.(1-7) The belief has become widely pervasive in the medical community, as well as the public at large, that any kind of CAA entails an increased risk of SCD, especially during sports activities. This belief was underscored by the landmark Bethesdaguidelines published in 1994 by the 26th Bethesda Conference for determining eligibility for competition in athletes with cardiovascular abnormalities.(8) The authors alluded to “coronary anomalies” as a generic label and stated that 24% of deaths in athletes were due to CAA. Recent, more advanced studies have clarified that about 5% of the general population carries some kind of CAA, but only a few types of CAA (likely some 0.1-1%) by means of specific, plausible and possibly quantifiable mechanisms have a high risk of severity. (9-11) Unfortunately, in athletes, some 80% of the cases of SCD considered to be due to CAA had that outcome as their first clinical manifestation. Sports activities are intrinsically competitive, involving a need for maximal physical performance. During training and especially during the competition itself, athletes exceed their usual level of physical activity going well beyond that reached during clinical stress testing. Sedentary persons have a lower probability of SCD (although their risk - and that associated with less aggressive sports activities - has not been evaluated in reasonable detail.) Until specific studies are conducted according to strict criteria and protocols, the extent of population screening that could be justified is still unclear.

The current procedure for screening athletes involves an annual medical exam prior to the beginning of the athlete’s season. The exam consists of listening to complaints that a candidate may volunteer, checking blood pressure and measuring height and weight. The physician will also listen with a stethoscope to theheart and lungs of the athlete. Only at the university and professional level, do some physicians elect to use instrumental testing, like an EKG and/or an echocardiogram to screen for a heart condition. And, while an EKG is an inexpensive and expeditious test, it often produces false negative or false positive ekgresults that can only confuse the public. Moreover, the echocardiogram is only reliable in identifying some 50-70% of the important coronary anomalies, which has resulted in the test not being considered an indicated screening test. When CAT Scan Angiography is used, it involves the use of a significant iodizing radiation dose and an intravenous injection of iodine contrast. The MRI, with the characteristics employed in our study, has a virtual 100% accuracy which will need to be confirmed and demonstrated in a large prospective series, as we are planning to implement.

Likely, close to 1% of the general population carries anomalous origin of a coronary artery from the opposite sinus (hereinafter “ACAOS”). If young athletes in the United States are 5 million per year, about 50,000 are expected to have one of such anomalies.

In particular, 0.1% of the general population is expected to carry L-ACAOS, which implies that in any given year 5,000 young athletes are at the highest risk. Some 0.9% of the general population is expected to a carry the other significant, but less serious variant, R-ACAOS accounting for 45,000 cases in the nation. CCAA Cares

1 Maron BJ, Roberts WC, McAllister HA, Rosing DR, Epstein SE. Sudden death in young athletes. Circulation. 1980; 62(2):218-229.
2 Frescura C, Basso C, Thiene G, et al. Anomalous origin of coronary arteries and risk of sudden death: a study based on an autopsy population of congenital heart disease. Hum Pathol. 1998; 29:689-695.
3 Corrado D, Basso C, Rizzoli G, Schiavon M, Thiene G. Does sports activity enhance the risk of sudden death in adolescents and young adults? J Am Coll Cardiol. 2003; 42:1959-1963.
4 Maron BJ. Sudden death in young athletes. N Engl J Med. 2003; 349:1064-1075.
5 Mirchandani S, Phoon CK. Management of anomalous coronary arteries from the contralateral sinus. Int J Cardiol. 2005;102: 383-389.
6 Maron BJ, Thompson PD, Ackerman MJ, et al; American Heart Association Council on Nutrition, Physical Activity, and Metabolism. Recommendations and considerations related to preparticipation screening for cardiovascular abnormalities in competitive athletes: 2007 update: a scientific statement from the American Heart Association Council on Nutrition, Physical Activity, and Metabolism: endorsed by the American  College of Cardiology Foundation. Circulation. 2007; 115:1643-1655.
7 Cheitlin MD, De Castro CM, McAllister HA. Sudden death as a complication of anomalous left coronary origin from the anterior sinus of Valsalva, a not-so-minor congenital anomaly. Circulation. 1974; 50:780-787.
8 Maron BJ, Thompson PD, Puffer JC, et al. Cardiovascular preparticipation screening ofcompetitive athletes. A statement for health professionals from the Sudden Death Committee (clinical cardiology) and Congenital Cardiac Defects Committee (cardiovascular disease in the young), American Heart Association. Circulation. 1996; 94:850-856.
9 Taylor AJ, Byers JP, Cheitlin MD, Virmani R. Anomalous right or left coronary artery from the contralateral coronary sinus: “high-risk” abnormalities in the initial coronary artery course and heterogeneous clinical outcomes. Am Heart J. 1997; 133:428-423.
10 Angelini P, Velasco JA, Flamm S. Coronary anomalies: incidence, pathophysiology, and clinical relevance. Circulation. 2002; 105:2449-2454.
11 Angelini P, Walmsley RP, Libreros A, Ott DA. Symptomatic anomalous origination of the left coronary artery from the opposite sinus of valsalva. Clinical presentations, diagnosis, and surgical repair. Tex Heart Inst J. 2006; 33:171-179.

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