Asian Cardiovasc Thorac Ann 1999;7:244-246
© 1999 Asia Publishing EXchange Pte Ltd
Anomalous Origin and Course of Left Anterior Descending Coronary Artery
Durgaprasad Rajasekhar, DM,
Probal Ghosh, MCh,
Abha Chandra, MCh,1,
Narendranath Raju, MD
Department of Cardiology
1 Department of Cardiac Surgery
Sri Venkateswara Institute of Medical Sciences
Tirupati, Andhra Pradesh, India
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For reprint information contact: Durgaprasad Rajasekhar, DM Tel: 91 8574 51222 Ext 2369 Fax: 91 8574 28803 Department of Cardiology, Sri Venkateswara Institute of Medical Sciences, Tirupati, AP 517507, India.
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Abstract
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A 56-year-old female with exertional angina had signs of ischemia on an exercise electrocardiogram. Coronary arteriography revealed anomalous origin of the left anterior descending coronary artery from the right coronary artery. The initial portion was septal and it then coursed between the aorta and the pulmonary artery. The patient declined surgical revascularization.
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Introduction
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Anomalous origin of a coronary artery from the contralateral sinus predisposes to myocardial ischemia and sudden cardiac death. In an autopsy study, the incidence of sudden cardiac death was reported to be 57% among 49 cases of anomalous left coronary artery.1 Such anomalies are identified in 0.1% to 0.3% of patients undergoing coronary angiography.2 While some patients die suddenly, others live a normal life-span with an unrepaired anomalous coronary artery.3 Contributory factors to sudden death include anomalous course, either intramyocardial or intraarterial, reduction of the aorto-coronary angle with exercise, slit-like orifice, vasospasm, and sudden kinking of the anomalous vessel.4 We report a case of anomalous left anterior descending coronary artery arising from the right common trunk and coursing between the aorta and the pulmonary artery.
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Case Report
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A 56-year-old female presented with exertional angina of 10 years duration. There was an increase in severity of the angina over the previous 3 months. Coronary risk factors were absent. Physical examination showed a pulse rate of 70 beats•min–1 and blood pressure of 140/80 mm Hg. Systemic examination was unremarkable. Her resting electrocardiogram was within normal limits and no abnormality was detected by echocardiography. An exercise electrocardiogram was positive for ischemia with a 2-mm ST-segment depression in the anterior leads at 5 mets workload. Since the angina was not controlled with medication, coronary arteriography was performed.
Left coronary arteriography revealed the left main coronary artery arising from the left sinus and continuing as the left circumflex artery with two obtuse marginal arteries (Figure 1
). Right coronary arteriography (Figures 2 and 3) revealed the right common trunk arising from the right sinus and immediately dividing into a right coronary artery that ran in the coronary sulcus and a left anterior descending coronary artery (LAD). The LAD had an anomalous mixed course. The initial portion was intramural. After giving rise to the septal perforator artery (Figure 2), the LAD looped back in a U shape to run between the aorta and the pulmonary artery on its way to the anterior inter-ventricular groove. These abnormalities were confirmed in the right anterior oblique view (Figure 2) and a steep left anterior oblique view (Figure 3). There was no sign of coronary atherosclerosis but there was evidence of bridging of the septal (intramyocardial) portion of the U loop of the LAD. Left ventriculography showed normal wall motion. With a diagnosis of anomalous LAD from the right coronary artery and anomalous intramural (septal) and interarterial course, and in view of the positive stress test, the patient was advised to undergo surgical revascularization of the LAD. However, she declined surgery and is being followed up with medication.
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Figure 1. Left coronary arteriogram in right anterior oblique view with a Judkins left catheter showing the left main coronary artery arising from the left sinus and continuing as the left circumflex artery.
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Figure 2. Right coronary arteriogram in right anterior oblique view with a Judkins right catheter, showing a right common trunk dividing into the right coronary artery and the left anterior descending coronary artery. The initial portion of the left anterior descending coronary artery is intramural and it loops in a U shape to become interarterial.
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Figure 3. Right coronary arteriogram in steep left anterior oblique view, confirming the findings in Figure 2 .
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Discussion
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The clinical outcome in patients with an anomalous coronary artery from the contralateral sinus is heterogenous.4 Manifestations include angina, syncope, myocardial infarction, and sudden cardiac death.5 The incidence of the most dreaded feature, sudden death, varies from 25% for anomalous right coronary artery to 57% for anomalous left coronary artery.1 The risk is moderate when the anomalous LAD arises from the right sinus. The incidence of an anomalous LAD arising from the right sinus was found to be 0.03% of all coronary arteriographies and formed 2.3% of all congenital coronary anomalies in a series of 126,595 patients.2
Emphasis is now placed on the initial course of the anomalous artery in deciding the risk of sudden cardiac death.4 Five anatomical subtypes have been classified according to the relationship of the anomalous coronary artery with the aorta and the pulmonary artery, namely anterior, between, septal, posterior, and combined.2 While the septal subtype is the most common, the between subtype is potentially the most serious variant. In one series, 8.9% of anomalous left coronary arteries coursed between the aorta and the pulmonary artery.5 The combined subtype is usually a combination of septal with anterior or posterior subtypes.2 Our patient had a combined subtype of anomaly comprising septal and between subtypes. This is very rare. This case also highlights that survival into the sixth decade of life is possible even with a between subtype.
In any case of aberrant origin of the left coronary artery from the right sinus, there is an increased risk of sudden death, especially if there is evidence of myocardial ischemia. It is agreed that surgical revascularization is indicated in this situation.6 Various surgical techniques are now available for such cases. In the absence of peripheral coronary vascular disease, operative treatment should maintain antegrade coronary perfusion. Coronary artery bypass grafting (left internal mammary artery or saphenous vein graft) should be reserved for cases with documented coronary atherosclerotic disease of the anomalous artery. Reimplantation of the anomalous left coronary artery in the left sinus of Valsalva has been described.6 This operation may have an increased risk of kinking of the coronary artery or neo-ostial obstruction, as a true button cannot be obtained due to the intramural course of the vessel. Better antegrade coronary perfusion can be achieved by unroofing the coronary sinus.7,8 Such a technique, first described by Mustafa and colleagues,7 consists of unroofing the intramural segment of the left coronary artery and construction of a neo-ostium in the respective coronary sinus. This technique has the dis-advantage of temporary detachment of the intercoronary commissure to unroof the intramural course of the coronary artery with inherent risk of postoperative aortic valve regurgitation. van Son and Mohr8 described a modified technique that has the advantage of avoiding detachment of the intercoronary commissure, hence lessening the potential for aortic regurgitation. In the modified technique, a 1-mm or 1.5-mm coronary probe is passed from the ostium of the left coronary artery into the intramural segment. The distal intramural segment is incised up to its exit site from the aortic wall. A neo-ostium is created by suturing the circumference of the coronary arterial wall to the intima of the left sinus.
Our patient declined surgery and it has been shown recently that with increasing age, the risk of sudden cardiac death in patients with anomalous coronary arteries is reduced.4 The same autopsy study showed that deaths beyond 30 years of age were usually unrelated to exertion or the coronary anomaly.
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References
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Taylor AJ, Rogan KM, Virmani R. Sudden cardiac death associated with isolated congenital coronary artery anomalies. J Am Coll Cardiol 1992;20:640–7.[Abstract]
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Taylor AJ, Byers JP, Cheitlim MD, Virmani R. Anomalous right or left coronary artery from the contralateral coronary sinus: high risk abnormalities in the initial course and heterogeneous clinical outcomes. Am Heart J 1997;133:428–35.[Medline]
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Buscenez D, Messmer BJ, Giller A, Von Bernuth G. Management of anomalous origin of the left coronary artery from right sinus of Valsalva. J Thorac Cardiovasc Surg 1994;107:1370–4.[Free Full Text]
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Mustafa J, Gula G, Radley Smith R, Durrer S, Yacoub M. Anomalous origin of the left coronary artery from the anterior aortic sinus: a potential cause of sudden death. J Thorac Cardiovasc Surg 1981;82:297–300.[Medline]
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van Son JAM, Mohr FW. Modified unroofing procedure in anomalous aortic origin of left or right coronary artery. Ann Thorac Surg 1997;64:568–9.[Abstract/Free Full Text]
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Abstract
Introduction
