Ann Thorac Surg 2002;73:1636-1638
© 2002 The Society of Thoracic Surgeons
Case report
Atypical presentation of an anomalous origin of the right coronary artery with severe compression between the great vessels
Sylvie K. Giroux, MDa,
Raymond Cartier, MD*b
a Department of Medicine, McGill University, Research Center, and Department of Surgery, Montreal Heart Institute, Quebec, Canada
b Department of Surgery, University of Montreal, Montreal, Quebec, Canada
Accepted for publication September 21, 2001.
* Address reprint requests to Dr Cartier, Department of Surgery, Montreal Heart Institute, 5000 Belanger St East, Montreal, Quebec H1T 1C8, Canada
e-mail: rc2910{at}aol.com
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Abstract
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Anomalous aortic origin of the right coronary artery is a rare coronary anomaly which, in a minority of cases, can cause clinical manifestations such as ischemic chest pain or arrhythmic syncope. We describe a case of anomalous aortic origin of the right coronary artery characterized by signs of left heart failure associated with ventricular tachycardia.
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Introduction
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Congenital anomalies of the coronary arteries are relatively rare: they are found in 1.3% of all patients undergoing coronary arteriography [1]. Anomalous aortic origin of the right coronary artery (RCA) represents 8% of these congenital malformations and was considered benign for many years [2]. But, in 1982, Roberts and colleagues [3] have clearly shown that the anomaly can cause clinical manifestations such as effort angina, myocardial infarction, ventricular tachycardia (VT), or sudden death. We report the case of a patient whose clinical presentation was quite atypical.
A 37-year-old man was admitted to the hospital for fatigue and shortness of breath lasting for 2 days without other symptoms. His medical history was negative except for bilateral cataracts treated surgically 7 years before. He had no risk factors for coronary artery disease. His fatigue and shortness of breath were not associated with chest pain or palpitations, although he reported two episodes of mild chest pain, in the past year during strenuous exercise.
Physical examination revealed a patient pale and lightly dyspneic at rest. Moist rales were audible bilaterally on pulmonary auscultation. The heart rate was regular but over 200/min and blood pressure was 110/80 mm Hg. Abdominal examination was irrelevant and there was no peripheral edema.
The electrocardiogram made on admission showed a VT at a rate of 242/min (Fig 1).
This tachyarrhythmia was converted to sinus rhythm by a direct current shock of 150 joules. There were signs of bilateral pulmonary congestion on chest roentgenogram. Echocardiogram revealed mild diffuse hypokinesia of the left ventricle which was more evident in inferior and posterior segments. The electrocardiogram obtained after conversion into sinus rhythm showed left anterior hemiblock and profound T-wave abnormalities in anterolateral and inferior leads. Serum levels of cardiac enzymes were normal.
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Fig 1. Twelve-lead electrocardiogram recorded on admission at the emergency room and showing ventricular tachycardia at a rate of 242/min.
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There was no recurrence of VT and signs of heart failure progressively regressed after initiation of medical therapy (amiodarone, furosemide, enalapril). Treadmill exercise test was stopped at 4.8 mets (Bruce protocol) because of fatigue without electrocardiographic changes or chest pain. A sestamibi-dipyridamole myocardial scintigraphy revealed evidence of ischemia in the posterior and inferior segments of the left ventricle. Interestingly, 7 days after admission, a control echocardiogram was normal.
An electrophysiologic study was performed and failed to induce VT. Coronary angiography showed an anomalous aortic origin of the dominant RCA behind the left aortic sinus of Valsalva; in the proximal portion of the anomalous artery, there was a 70% narrowing which seemed to be caused by compression between pulmonary artery and aorta (Fig 2).
The left anterior descending artery and the circumflex artery had a normal appearance.
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Fig 2. Coronary injection in the left sinus of Valsalva in the right anterior oblique projection showing severe narrowing (arrow) of the proximal portion of the right coronary artery (RCA) during its course between the pulmonary artery and aorta; the left anterior descending aorta (LAD) and the circumflex (Cx) have a normal appearance.
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Because of the severe clinical consequences of the malformation, it was decided to bypass the right coronary artery using the right internal mammary artery as a conduit. At the time of operation, we observed definite compression of the anomalous artery during its course between the great vessels without evidence of endoluminal atherosclerotic lesion. There was no postoperative complication except for episodes of paroxystic atrial flutter. A control sestamibi-dipyridamole scintigraphy demonstrated normal myocardial perfusion without signs of ischemia. The patient remains totally asymptomatic since myocardial revascularization.
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Comment
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Kragel and Roberts [4] have classified anomalous aortic origin of the right coronary artery into four types. This classification is based upon the location of the abnormal ostium: behind or above the left sinus of Valsalva, above the commissure between the right and left cusps, or from a common ostium with the left main coronary artery (Fig 3).
The shape of the ostium may be round or, more frequently, slit-like. In a minority of cases, the anomaly is associated with serious clinical events [3]. The anatomical type and the shape of the ostium are not predictors of clinical significance, but coronary dominance has been demonstrated to have a predictor role since there are no clinical consequences when the left circumflex coronary artery is dominant [4].
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Fig 3. Coronary anatomy in cases of anomalous origin of the right coronary artery (RCA) from the aorta. (A) Anomalous origin of the RCA from behind the left sinus of Valsalva. (B) Anomalous origin of the RCA from above the left sinus of Valsalva. (C) Anomalous origin of the RCA from above the commissure between the right and left sinus. (D) Anomalous origin of the RCA from a common ostium with the left main coronary artery. (A = anterior cusp; L = left cusp; LMCA = left main coronary artery; NC = noncoronary cusp; PV = pulmonary valve; R = right cusp.)
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The clinical manifestations include effort angina, myocardial infarction, VT or ventricular fibrillation, which often occur during or shortly after vigorous exercise. There is no doubt that these manifestations result from myocardial ischemia: physiologic studies have demonstrated that this kind of anomaly may be associated with an important impairment of coronary reserve [5]. Two pathophysiologic mechanisms may act independently or simultaneously: (1) compression of the anomalous artery during its course between the great vessels; and (2) compression of the slit-like orifice of the anomalous artery as the aorta dilates. In our patient, there was severe compression of the right coronary artery by the great vessels; the resulting myocardial ischemia has probably initiated a nonsyncopal VT which caused a "stunned myocardium" with clinical symptoms and signs of left ventricular failure.
The diagnosis must be suspected mainly in young adults without coronary risk factors and presenting with effort angina, myocardial infarction, or malignant ventricular arrhythmia. The potential of myocardial ischemia can be confirmed by standard exercise testing but false negatives may occur. Stress thallium-201 or sestamibi scanning has a better sensitivity, although a negative test result does not rule out ischemia. The malformation can be visualized by transesophageal echocardiography and also by magnetic resonance angiography which can confirm the course of the artery. But, coronary angiography remains the gold-standard for diagnosis: the RCA ostium cannot be visualized at its usual site, and the abnormal site is visualized and verified by an aortic root angiogram and by selective injection of RCA originating in the left sinus of Valsalva.
There is indication for surgical treatment if there is evidence of myocardial ischemia producing clinical symptoms [3]. Methods of surgical correction include ostial reconstruction, translocation of the vessel origin, and coronary artery bypass grafting [5, 6]. Ostial reconstruction does not correct ischemia resulting from distal compression, and results of reimplantation in the right coronary cusp have been disappointing [6]. Coronary artery bypass grafting is a procedure that restores distal flow to the RCA; the use of internal mammary artery as conduit is preferred because of its advantage of proven long-term patency when used in patients with coronary atherosclerosis.
In summary, we described a case of anomalous aortic origin of the RCA severely compressed between the great vessels with a rare clinical presentation, and characterized by signs of left heart failure associated with VT.
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Acknowledgments
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We gratefully acknowledge the contribution of Jacques Lespérance, MD, Department of Radiology, Montreal Heart Institute, who reviewed the coronary arteriogram and the entire manuscript.
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References
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Yamanaka O., Hobbs R.E. Coronary artery anomalies in 126,595 patients undergoing coronary arteriography. Cathet Cardiovasc Diagn 1990;21:28-40.[Medline]
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Roberts W.C., Siegel R.J., Zipes D.P. Origin of the right coronary artery from the left sinus of Valsalva and its functional consequences: analysis of 10 necropsy patients. Am J Cardiol 1982;49:883-888.
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Kragel A.H., Roberts W.C. Anomalous origin of either the right or left main coronary artery from the aorta with subsequent coursing between aorta and pulmonary trunk: analysis of 32 necropsy cases. Am J Cardiol 1988;62:771-777.[Medline]
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Chaitman B.R., Lespérance J., Saltiel J., et al. Clinical, angiographic and hemodynamic findings in patients with anomalous origin of the coronary arteries. Circulation 1976;53:122-131.[Abstract/Free Full Text]
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Izhar V., Lerman A., Olney B.A., et al. Minimally invasive direct coronary artery bypass—a surgical approach for anomalous right coronary artery from left aortic sinus of Valsalva. Mayo Clin Proc 1998;73:661-664.[Abstract/Free Full Text]
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Abstract
Introduction
