Anomalous origin of Coronary Artery (ALCAPA) in 64-channel TC scanner

Abstracts

A tomografia computadorizada multidetector (TCMD) com 64 canais disponibiliza para a prática clínica um excelente método para detecção de anomalias das artérias coronárias. O diagnóstico da anomalia coronariana consistindo da origem da artéria coronária esquerda no tronco pulmonar em adulto sem história prévia de doença congênita apresenta escassa casuística na literatura. Realizamos um relato de caso em uma paciente feminina de 30 anos de idade, com queixas de cansaço aos grandes esforços e cintilografia positiva para isquemia. O diagnóstico foi realizado pela TCMD de 64 canais e com isso verifica-se que o método pode ser utilizado como de primeira linha.

Tomografia; coronariopatia; cardiopatias congênitas

CASE REPORT

^INational Institutes of Health Clinical Center, Bethesda, MD, EUA

^IIUniversidade Federal do Rio de Janeiro

^IIIHospital Pró-Cardíaco, Rio de Janeiro, RJ

^IVUniversidade Federal Fluminense, Niterói, RJ;

^VInstituto do Coração (InCor) do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, SP - Brasil

Mailing address

SUMMARY

Multidetector computed tomography (MDCT) with 64 channels provides to clinical practice an excellent method to detect coronary artery anomalies. The diagnosis of coronary anomalies consisting of origin of left coronary artery in the pulmonary trunk in adults with no history of congenital disease has few reports in literature. We report a case in a 30-year old female patient complaining of fatigue on major efforts and positive scintigraphy for ischemia. The diagnosis was made through 64-channel MDCT and thus it appears that the method can be used as baseline.

Key words: Tomography; coronary disease; heart defects, congenital.

Introduction

Normal coronary anatomy is characterized by two ostia centrally located in the right and left Valsalva sinus. Anomalies stemming from coronary arteries are estimated to be about 1% of the general population according to studies deriving from coronary angiography^1-4 performed in suspected obstructive diseases. In autopsy studies, we see a lower incidence, as in the study by Alexander and Griffiths⁵, in which 18,950 autopsies observed only 54 cases of origin anomalies (0.3%). These studies were limited due to selection of patient admissions and absence of clear diagnostic criteria. Congenital anomalies with hemodynamic consequences appear in isolation or as part of a secondary form associated with congenital heart disease. Moreover, suspicions that a particular clinical presentation is secondary to some anomalies deriving from coronary arteries, especially when it comes to young patients, remain a diagnostic challenge. This study describes a case of a young patient with dyspnea on major efforts and anomalies found in scintigraphy. The patient was referred to diagnostic evaluation with MDCT of coronary arteries.

Case Report

Female patient, Caucasian, 30-year-old, reported that a couple of months before she had noticed the onset of fatigue related to major efforts, such as climbing stairs or physical activities she used to perform regularly. She also reported that when she was 2, she had a poorly-defined episode of "inflammation of the heart", which was characterized as myocarditis. However, it was not investigated further. After consulting with a cardiologist, she underwent several tests, including echocardiography, which revealed a small left ventricular (LV) dilation and light dysfunction, and myocardial scintigraphy with pharmacological stress, which showed ischemia on the inferior wall.

The patient was referred to outpatient care to perform MDCT on a LightSpeed VCT 64 GE Healthcare device. She received 20 mg of intravenous metoprolol to control heart rate (HR), obtaining average HR of 70 bpm. Calcium scoring was analyzed through conventional acquisition with prospective synchronization and 3 mm collimation. Angiographic analysis used helical acquisition and retrospective electrocardiographic synchronization with 0.625 mm collimation during injection of 80 ml of nonionic contrast medium with a 5.0 ml/s flow. Twenty cardiac phases were reconstructed and the one with the lowest degree of cardiac motion at the level of the coronary arteries was selected. The best phase for coronary analysis in this case was that of 80%. For the analysis, we used axial imaging sources (Figure 1), multiplanar reformatting and three-dimensional curves and reconstructions per volume rendering with angiographic (Figure 2) and cardiac (Figure 3) reconstruction in ADW Workstation 4.3 (GE Healthcare).

Discussion

Anomalous Left Coronary Artery from Pulmonary Artery (ALCAPA) was first described in 1908 in a 60-year old female patient¹. Subsequently, Bland et al¹ described the same syndrome in 1933, studying the clinical and autopsy findings of a 3-month old child with dyspnea and myocardial infarction. The estimated incidence of ALCAPA is 1 for every 300,000 live births, representing a percentage between 0.24% and 0.46% of all congenital cardiac anomalies^6-10. Some believe that this is significantly underestimated because an unknown portion of patients may spend a lifetime asymptomatically and remain undiagnosed^7,8. The most common form of this syndrome is the left coronary artery coming out of the pulmonary artery and right coronary artery coming out of the aorta (Bland-White-Garland syndrome)¹, which is exactly the type of syndrome reported in this study. ALCAPA develops before birth when the blood and lung pressure is equal and there is an antegrade flow in both coronary arteries. In the neonatal period, this flow changes gradually as the pulmonary pressure decreases and the ductus arteriosus closes, leading to reversal of flow in the left coronary artery^6,9. The extent of myocardial ischemia in these patients is directly proportional to the development of collateral circulation between the right and left coronary arteries. If these patients with ALCAPA are not treated surgically, they usually present a rather unfavorable development, with reports of 90% mortality early in childhood^3,5. Such anomalous origin of coronary artery is extremely rare in adults and in the elderly⁷. The clinical features of this syndrome is generally nonspecific, with signs and symptoms such as syncope, arrhythmias, fatigue, nocturnal dyspnea and, less commonly, angina^1-5. On examination we can find systolic murmur and ischemic changes (lateral wall) or adverse consequences from myocardial infarction on electrocardiogram (ECG)^3,4,9. Chronic ischemia can be identified in tests with hemodynamic stress such as scintigraphy, echocardiography or magnetic magnetic resonance imaging^7,10.

Until recently, such diagnosis has been performed with coronary catheterization. However, this method has limited use for this purpose due to its invasive characteristic and forecast analysis. With the onset of synchronized electrocardiogram MDCT, we can now, noninvasively and accurately, detect the origin, the course and termination of anomalous origin of coronary arteries. Some authors have shown the extent to which MDCT of coronary arteries is far more efficient as compared to conventional angiography in demonstrating the ostial origin and the proximal course of anomalous coronary arteries^2,8,10.

The treatment of ALCAPA consists in the recreation of dual coronary perfusion. In children with this syndrome, you can directly deploy the anomalous coronary artery into the aorta or create an intrapulmonary conduit from the left coronary ostium into the aorta (Takeuchi procedure). In adults, the left coronary is usually tied to the pulmonary artery combined with grafting of the internal mammary artery or saphenous vein^3,5,7,8.

We do not have image data through MDCT in medium and long term monitoring of patients after surgery, but as it is a non-invasive method and provides accurate anatomical study, its use is well established^9,11.

The success of surgical procedures will depend on the initial myocardial condition at the time of diagnosis and the impact on the patient's clinical condition. Hence, the later such diagnosis is given, the greater will be the myocardial damage caused by ischemia and the greater will be the ventricular dysfunction and the degree of mitral regurgitation, which will impact the prognosis of these patients^4,7,9,11.

Potential Conflict of Interest

No potential conflict of interest relevant to this article was reported.

Sources of Funding

There were no external funding sources for this study.

Study Association

This study is not associated with any post-graduation program.

References

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• 7. Singh TP, Carli MF, Sullivan NM. Myocardial flow reserve in long-term survivors of repair of anomalous left coronary artery from pulmonary artery. J Am Coll Cardiol .1998;31(2):437-43.
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• 9. Shi H, Aschoff AJ, Brambs HJ, Hoffmann MH. Multislice CT imaging of anomalous coronary arteries. Eur Radiol. 2004;14(12):2172-81.
• 10. Wesselhoeft H, Fawcett JS, Johnson AL. Anomalous origin of the left coronary artery from the pulmonary trunk: its clinical spectrum, pathology and pathophysiology, based on review of 140 cases with seven further cases. Circulation .1968;38(2):403-25
• 11. Brown JW, Ruzmetov M, Parent JJ, Rodelfed MD, Turrentine MW.. Does the degree of preoperative mitral regurgitation predict survival or the need for mitral valve repair or replacement in patients with anomalous origin of the left coronary artery from the pulmonary artery? J Thorac Cardiovasc Surg. 2008; 136(3): 743-8.

Anomalous origin of Coronary Artery (ALCAPA) in 64-channel TC scanner

Marcelo Souto Nacif^{I, III, IV}; José Hugo Mendes Luz^III; Denise Madeira Moreira^{II, III}; Carlos Eduardo Rochitte^{III, V}; Amarino Carvalho de Oliveira Júnior^III

Publication Dates

• Publication in this collection
  12 July 2010
• Date of issue
  June 2010

History

• Reviewed
  10 Nov 2009
• Received
  16 Apr 2009
• Accepted
  11 Dec 2009