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Anomalous coronary origin: the challenge in preventing exercise-related sudden cardiac death
  1. C P Edwards1,3,
  2. A Yavari1,
  3. M N Sheppard2,
  4. S Sharma1,3
  1. 1Department of Cardiology, University Hospital Lewisham, London, UK
  2. 2Department of Pathology, Royal Brompton Hospital, London, UK
  3. 3Department of Cardiology, King's College Hospital, London, UK
  1. Correspondence to Dr S Sharma, Department of Cardiology, Kings College Hospital, Denmark Hill, London SE5 9RS, UK; sanjay.sharma{at}kch.nhs.uk

Abstract

The sudden cardiac death (SCD) of a young athlete is a catastrophic event, particularly in the absence of prodromal warning symptoms. Anomalous coronary origin (ACO) is a well-described cause of cardiac symptoms and SCD, but the diagnosis is usually missed by conventional non-invasive investigations designed to identify myocardial ischaemia. SCD is preventable by correction of the anomaly. A tragic case of a promising young athlete who had underlying ACO and who presented with prodromal symptoms with multiple “negative” investigations is described to highlight the typical clinical features and outline the difficulties encountered in accurate premortem diagnosis.

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Sudden cardiac death (SCD) in the young athlete is a tragic occurrence, most commonly occurring during or immediately after exercise and is usually the result of undetected cardiovascular disease.1 The precise scale of the problem remains undefined, although most accurate estimates suggest an incidence of 1–2/100 000 per year.1 2 Hypertrophic cardiomyopathy is the most commonly identified underlying condition worldwide,3 followed closely by congenital coronary artery anomalies (CCAA), which are implicated in 10–20% of all deaths in young athletes.1,,3 Unfortunately, individuals with CCAA are often asymptomatic and sudden death is the first presentation. The diagnosis is rarely possible with routine exercise electrocardiography. The following case highlights the challenge faced in diagnosing the disorder even in a symptomatic individual.

Case report

A 15-year-old Afro-Caribbean boy was referred for assessment after experiencing three episodes of “pressure-like” chest discomfort associated with dizziness, of which two occurred on exertion and one at rest. He had previously been well with no significant past medical history. There was no history of illicit drug use or family history of premature coronary artery disease or sudden death. He was an athletic individual with aspirations of playing professional football. Physical examination was normal.

He was investigated with a 12-lead electrocardiogram (ECG), transthoracic echocardiogram, exercise stress test and 24-h ambulatory ECG monitor. The 12-lead ECG showed sinus rhythm with Sokolow–Lyon voltage criteria for left ventricular hypertrophy. There was minor J point elevation in leads V2–V3, although no other repolarisation abnormalities were present. Transthoracic echocardiography (TEE) revealed structurally normal cardiac chambers and valves. The origin of the left coronary artery was identified, but satisfactory images of the origin of the right coronary artery could not be obtained. During stress testing, he completed 13 minutes of the Bruce protocol, achieving a maximum heart rate of 181 beats per minute (88% age predicted) with a normal blood pressure response. The athlete was asymptomatic throughout and stopped as a result of fatigue. The ECG did not exhibit any ischaemic changes or arrhythmias. A 24-h ambulatory ECG showed sinus rhythm with infrequent ventricular ectopy (<200/24 h) and no evidence of ST segment shift. The total serum cholesterol was normal at 3.8 mmol/l.

No obvious cause for his symptoms was identified and the athlete was reassured and allowed to continue playing competitive sport. He subsequently collapsed playing football and could not be resuscitated.

Postmortem examination of the heart revealed mild left ventricular hypertrophy with no evidence of myocyte disarray. There was an anomalous origin to the right coronary artery from the left aortic sinus with extension between the great vessels (figs 1 and 2).

Figure 1

Image of the left coronary sinus with aortic leaflet removed. The arrows demonstrate the ostia of both coronary arteries arising from the left coronary sinus. LCA, left coronary artery; RCA, right coronary artery.

Figure 2

Image of the anomalous right coronary artery (black arrow) extending between the aorta and pulmonary artery.

Discussion

Congenital coronary artery anomalies are widely accepted as a common cause of SCD in young athletes. The prevalence of CCAA in the general population ranges between 0.2% and 5.6%.4,,6 Ambiguity remains as to the true prevalence of CCAA as normal coronary anatomy shows a high degree of heterogeneity. The estimate of 5.6% is based upon a study of 1950 subjects who underwent coronary angiography performed by Angelini et al.6 They defined a CCAA as any form of coronary anatomy occurring in less that 1% of the population. Using this definition they found a CCAA in 5.6% of the population and suggested a comprehensive classification for the anomalies identified. Whereas that study highlights the degree of variability seen in the normal coronary anatomy, reports of sudden deaths due to CCAA are invariably the result of an anomalous coronary origin (ACO) from the opposite coronary sinus. In the study by Angelini et al6 they found the incidence of ACO from the opposite sinus was 1.07%. A right ACO from the left coronary sinus was seen in 0.92% of cases and a left ACO from the right coronary sinus was seen in 0.15% of cases. Whether ACO is hereditary remains a matter of debate. A genetic cause has recently been suggested by a case series of five families in which two relatives have been identified with the condition.7 In contrast, a reported case of an identical twin who died suddenly as a result of ACO in which no anomaly was identified in the surviving twin suggests a different cause.8

The association between CCAA and sudden death has been investigated by autopsy studies of individuals who have undertaken high levels of exertion. A retrospective cohort study of 6.3 million US military recruits over a 25-year period identified 126 cases of non-traumatic death,9 in whom a CCAA was identified as the cause of death in 21 cases, accounting for 17% of deaths. A left ACO was found to be responsible at postmortem in all cases. Basso et al10 investigated 27 athletes found to have died of CCAA, all of whom died during or immediately following exertion. Of the 27 deaths, 23 were attributed to left ACO and four to right ACO. These data suggest that whereas left ACO are less prevalent in the population they carry a worse prognosis. A course of the anomalous artery between the aorta and the pulmonary artery has also been associated with an increased risk of sudden death.5 The exact mechanism leading to ischaemia remains a matter of debate, although is likely to be more complex than the traditionally described aortopulmonary “scissor” effect.

Whereas it is clear that CCAA are a common cause of SCD, our case highlights the diagnostic challenge faced in identifying such lesions in the living. The study of Basso et al10 found that less than half of the individuals had experienced symptoms including syncope, chest pain, palpitations or dizziness before death. Of those athletes, 15 had undergone clinical evaluation as part of the long-standing national preparticipation screening programme for competitive athletes in Italy. All athletes investigated had normal resting 12-lead ECG. In addition, six athletes underwent stress ECG without abnormality. The inability to identify CCAA utilising basic investigations such as resting and exercise electrocardiography is underscored by the 25-year Italian preparticipation screening experience, which has resulted in a 90% reduction in the incidence of exercise-related SCD, predominantly as a result of the identification of the cardiomyopathies; however, the number of deaths from CCAA remains unchanged.

TTE has been shown to be a useful non-invasive means of identifying coronary artery origin in young athletic individuals. Pelliccia et al11 demonstrated in 1360 competitive athletes that the origin of the left main stem and right coronary arteries could be identified in 97% and 80% of cases, respectively.

Our case highlights the need for further cardiac imaging in symptomatic individuals in whom the origin of both coronary arteries are not identified with TTE. Selective coronary artery catheterisation is considered the gold standard investigation for identifying ACO, although it is invasive and carries a small risk. Magnetic resonance coronary angiography (MRCA) and computed tomography angiography (CTA) have been shown in case controlled studies to be equally effective at identifying ACO as selective coronary artery catheterisation.12 In addition, MRCA or CTA offer a three-dimensional depiction of the anomalous artery's course providing information about its relationship with surrounding structures, which is useful in identifying highrisk anomalies such as a course between the great vessels as well as allowing preoperative planning for surgical repair.

Once CCAA has been identified, there are two treatment options: conservative management and surgical repair.5 Conservative management involves abstinence from athletic activity and pharmacotherapy with beta-blockade to reduce possible myocardial ischaemia. ACO with a course between the great vessels is believed to carry a severe prognosis and surgical correction is deemed the treatment of choice. “Unroofing” of the intramural course of the anomalous vessel and direct reimplantation of the anomalous artery are common surgical approaches.5 13

In conclusion, ACO occur in up to 1% of the population and are a leading cause of sudden death in young athletes. ACO do not always cause symptoms and sudden death is often the first presentation. In symptomatic individuals, an ACO should be considered with a high degree of suspicion. Our case highlights that resting and stress electrocardiography should play a limited role in the diagnosis or exclusion of ACO. Imaging the coronary sinus is essential to exclude this condition. In the majority of cases TTE may be useful, although only if the origin of both coronary arteries is identified. In symptomatic individuals, defining the true coronary anatomy with MRCA, CTA or selective coronary artery catheterisation is essential to exclude this treatable cause of SCD.

What is already known on this topic

Anomalous coronary arteries are a common and preventable cause of SCD in athletes.

What this study adds

  • ▶. This case highlights the need to consider anomalous coronary arteries with a high degree of suspicion in all athletes who experience cardiac symptoms.

  • ▶. Once considered, normal stress electrocardiography is not sufficient to exclude this disorder and imaging of the origin of both coronary arteries is essential.

References

View Abstract

Footnotes

  • Funding CE is funded by a research grant from the charitable organisation Cardiac Risk in the Young.

  • Competing interests None.

  • Patient consent Obtained.

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