Ann Thorac Surg 2004;78:1082-1084
© 2004 The Society of Thoracic Surgeons
Case report
Anomalous origin of the left coronary artery from the pulmonary artery in an adult with systemic collateral circulation to the left coronary artery
Alfredo J. Rodrigues, MD, PhDa,*,
Walter V. A. Vicente, MD, PhDa,
Solange Bassetto, MDa,
Adilson Scorzoni Filho, MDa
a Division of Cardiothoracic Surgery, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
Accepted for publication June 23, 2003.
* Address reprint requests to Dr Rodrigues, Divisão de Cirurgia Torácica e Cardiovascular, Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto da USP, Campus Universitário, Monte Alegre, Ribeirão Preto, SP, Brazil
alfredo{at}cardiol.br
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Abstract
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A case of anomalous origin of the left coronary artery from the pulmonary artery in an adult with collateral circulation between the left coronary artery and systemic extracardiac vessels is reported. After evaluating the surgical options, my colleagues and I conclude that ligation of the left coronary artery and a left internal thoracic artery graft to the left anterior descending coronary artery is the preferable option for treating such patients.
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Introduction
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Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) is rarely reported in adults, because 90% of untreated infants die in the first year of life [1, 2]. A 33-year-old woman was referred to our institution with the diagnosis of mitral valve regurgitation. Her main symptoms were occasional dyspnea (New York Heart Association class II) and nonspecific chest pain. On physical examination a grade 2/6 systolic murmur, loudest at the apex, was audible, as was a continuous murmur over the left upper sternal border.
The patient's chest radiogram and electrocardiogram showed no abnormality. The transthoracic echocardiogram revealed mild mitral regurgitation and a dilated right coronary artery (RCA; 8.5 mm) arising from the aorta. The origin of the left coronary artery (LCA) was not identified, but diastolic flow from the RCA to the LCA was observed by color Doppler imaging, suggesting ALCAPA. The exercise thallium 201 scintigram showed mild to moderate ischemia in the area of distribution of the left anterior descending coronary artery (LAD) and transient ventricular dilation at 10 metabolic equivalents of workload on the treadmill. The coronary angiogram confirmed the diagnosis of ALCAPA, demonstrating collateral circulation between the RCA and LCA and a coronary steal phenomenon into the pulmonary artery (PA). The patient was referred for surgical treatment. Given that the mitral regurgitation was mild and probably ischemic in origin, my colleagues and I planned ligation of the LCA and a left internal thoracic artery (LITA) graft to the LAD to increase myocardial perfusion.
During operation, a distended and tortuous RCA was observed. An enlarged LCA, approximately 1.5 cm long, was identified arising from the anterior sinus of the PA. Multiple collaterals between the RCA and LCA were present.
Cardiopulmonary bypass was established with cannulation of the ascending aorta and right atrium. The ascending aorta was cross-clamped, and the heart was arrested with isothermic hyperkalemic blood cardioplegia into the ascending aorta. The lower systemic temperature was 34°C. Because of the abundant intercoronary collaterals, delivery of the cardioplegic solution could be simplified by placing gentle digital pressure over the LCA as the cardioplegic solution was infused into the ascending aorta. The PA was opened with a longitudinal incision, and the ostium of the LCA was identified in the anterior sinus. Continuous blood flow from the LCA and resumption of a slow mechanical activity of the heart were noticeable, despite the absence of flow through the ascending aorta, raising the suspicion of systemic collateral blood flow to the LCA. The LCA was encircled and doubly ligated with 3-0 cotton suture. Gentle compression over the atrioventricular groove lessened the blood flow through the LAD, facilitating the anastomosis with the LITA.
The postoperative period was uneventful. Coronary angiography performed just before hospital discharge revealed no flow from the LCA to the PA. There was competitive blood flow on the LAD (Fig 1A) between the LITA and systemic extracardiac vessels (retrograde flow). Contrast injection into an arterial branch arising from the descending thoracic aorta confirmed the systemic blood supply to the LCA (Fig 1B).
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Fig 1. Postoperative coronary arteriography demonstrating (A) the LITA (upper black arrow) graft to the LAD (lower black arrow) and the lack of progression of the contrast (white arrow) into the LAD because of competitive blood flow and (B) a left coronary artery branch (white arrow) filled by radiologic contrast after ejection into a branch of the descending thoracic aorta. (LAD = left anterior descending artery; LITA = left internal thoracic artery.)
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Three months later, repeat exercise thallium scintigraphy showed mild ischemia in the distribution of the LAD and an ejection fraction of 46%. Mild mitral regurgitation was still detectable on transthoracic echocardiography. Six months after the operation, the patient had no symptoms and had resumed her normal daily activities.
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Comment
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The presence of collateral circulation between coronary arteries and systemic extracardiac vessels [3], mainly the bronchial arteries, is sporadically described in ALCAPA [4, 5]. Along with the more commonly described intercoronary collaterals, these more rarely described systemic collaterals certainly contribute to survival with ALCAPA into adulthood; therefore, concern about the role of these systemic collaterals may seem meaningless from a practical point of view.
In infants, direct reimplantation of the anomalous LCA into the aorta is the most frequently adopted surgical technique. When this procedure is not feasible, the creation of an intrapulmonary conduit from the left coronary ostia to the aorta (the Takeuchi procedure) may be used [1]. In adults, both the direct reimplantation of the LCA and the Takeuchi procedure may be technically more difficult. Therefore, simpler but equally effective procedures may be used, including either ligation of the LCA from the PA, or ligation of the LCA from the PA combined with coronary artery bypass grafting by using the internal thoracic artery or the saphenous vein [1].
Given that our patient had extensive systemic collaterals, should she have only the procedure of isolated ligation of the LCA, should ligation be combined with bypass grafting, or should she have the more technically complex procedure of either direct reimplantation or the Takeuchi procedure? Isolated ligation of the LCA is not the ideal procedure in cases of ALCAPA in which the only source of blood flow to the LCA is the RCA, because reduced long-term survival has been reported [1]. However, if there are also systemic collaterals, isolated ligation may be sufficient for myocardial perfusion, but this is not ensured. With bypass grafting, flow competition between the graft and systemic collaterals has been a matter of concern [6], making the future of the graft uncertain in such cases. As noted in the previous section describing the surgical procedure, flow competition was noted on our patient's postoperative angiogram between the LITA graft and systemic collateral vessels. However, the LITA seems to be less sensitive to competitive flow [7], and there has been evidence that the internal thoracic arteries are able to adapt to situations of chronic competitive flow, regaining full patency in the case of progression of coronary stenosis [8].
Weighing all the considerations, we conclude that adult patients with ALCAPA should always receive a graft to the LAD by using an in situ LITA, regardless of the existence of collateral RCA or LCA or systemic collateral circulation.
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References
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- Kirklin J, Barrat-Boyes B. Congenital anomalies of the coronary arteries. Cardiac surgery. 2nd ed. Vol. 2. New York: Churchill Livingstone Inc; 1993. 1167–93
- Moberg A. Anastomoses between extracardiac vessels and coronary arteries. I. Via bronchial arteries. Post-mortem angiographic study in adults and newborn infants. Acta Radiol Diagn (Stockh). 1967;6:177–192[Medline]
- Ishihata T, Takeda H, Katohno E, et al. An adult case of Bland-White-Garland syndrome with collaterals from the bronchial artery. Heart Vessels. 1994;9:218–222[Medline]
- Karolczak MA, Wieteska J, Bec L, Madry W. Anomalous origin of the left coronary artery (LCA) from pulmonary artery (Bland-White-Garland syndrome) with systemic collateral supply to LCA. Med Sci Monit. 2001;7:755–758[Medline]
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Abstract
Introduction
