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October-December 1994:269-271
Anomalous Origin of the Left Circumflex Coronary Artery from the Right Aortic Sinus of Valsalva and Sudden Death D o m e n i c o Corrado, MD, Tommaso Pennelli, MD, PierGiuseppe Piovesana MD, and Gaetano Thiene, M D
Departments of Pathology and Cardiology, University of Padua Medical School, Padua, Italy
++ Anomalous origin of the left circumflex coronary artery from the right aortic sinus is generally considered a benign condition. We report a 53-year-old man with clinical and pathologic evidence of myocardial infarction and sudden death in the setting of this anomaly, with no evidence of obstructive coronary atherosclerosis.
Origin of the left circumflex (LCx) coronary artery from the right aortic coronary sinus, the most common congenital coronary anomaly (1), is generally considered an anatomic variant without clinical relevance; nonetheless, it has been found occasionally in association with angina pectoris (2,3), myocardial infarction (3,4), and sudden death (1,5), in the absence of obstructive atherosclerotic coronary artery disease. We report further clinical and pathologic evidence that an anomalous LCx coronary artery in itself may precipitate myocardial infarction and sudden death.
Case Report A 53-year-old man was admitted to the coronary care unit because of precordial pain of 10 hours' duration. The patient's medical history was unremarkable; he had neither significant coronary risk factors nor history of lung disease or anemia. At the time of symptoms onset, the patient was not engaged in exertion and had no fever that may have contributed to a myocardial oxygen supply/demand imbalance. Clinical examination revealed no cardiac murmurs; systolic blood pressui'e was 130 mmHg. Electrocardiographic (ECG) tracings showed an ST-segment elevation in leads L2, L3, aVF, V5, and V6, as well as an ST-segment depression from V1 to V4. The patient was treated with aspirin and continuous nitroglycerin infusion. Chest X-ray findings were normal, and crossThis work was supported by the Juvenile Sudden Death Research Project of the Veneto Region, Venice and by National Council for Research, Target Project FAT.MA., Rome, Italy. Manuscript received April 12, 1993; accepted February 15, 1994. Address for reprints: Gaetano Thiene, MD, Istituto di Anatomia Patologica, Via A. Gabelli, 61, 35121 Padova, Italy. © 1994 by Elsevier Science Inc.
sectional echocardiogram showed posterolateral left ventricular wall akinesia with preserved ejection fraction. Serial ECG and serum enzyme determinations confirmed the diagnosis of acute "non-Q wave" myocardial infarction. The peak creatine phosphokinase level was 1800 I.U., with a myocardial fraction of 630 I.U. The clinical course was uneventful, and the patient was discharged on aspirin (100 mg/day). One month later the patient was readmitted for follow-up evaluation; unexpectedly he was found dead in the hospital bathroom in the early morning.
Necropsy and Histological Findings Postmortem examination disclosed a heart weight of 400 g and no significant alterations in chamber size or wall thickness. All cardiac valves were normal. Careful examination of the major epicardial coronary arteries revealed a balanced pattern, and no signs of obstructive (>/70% cross-sectional area narrowing) coronary atherosclerotic disease. The LCx coronary artery took off at an acute angle from the anterior right aortic sinus, separately from the fight coronary ostium (Figure 1A), and ran behind the aorta without an intramural course to reach the left atrioventricular groove (Figure 2A). All the coronary ostia were patent and devoid of atherosclerosis. A healed myocardial infarction was detected and consisted of a large subendocardial scar in the posterolateral wall of the left ventricle (Figure 1B), in the tributary myocardium of the anomalous LCx coronary artery. Histology confirmed the absence of obstructive atherosclerotic coronary artery disease (Figure 2B) and the presence of a postinfarction subendocardial fibrosis. 1054-8807/94/$7.00
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Pathologic examination of all other organs ruled out any life-threatening lesions. Toxicologic analysis of blood and urine specimens was negative.
Discussion
Figure 1. (A) Gross view of the aortic root showing the anomalous origin of the left circumflex coronary artery from the fight coronary sinus with a separate ostium. The right coronary artery is cut longitudinally. The arrow indicates the left coronary ostium. Dotted lines depict the proximal retroaortic course of the anomalous coronary artery with an acute take-off. (B) Healed myocardial infarction located in the posterolateral free wall of the left ventricle: note the dominant left circumflex coronary artery, devoid of significantly obstructive atherosclerosis, running in the left atrioventricular groove.
Origin of the LCx coronary artery from the right aortic sinus of Valsalva or from the proximal right coronary artery is not a rare congenital anomaly; indeed, in previous angiographic and pathologic series, its incidence was 0.4 % and 0.7 %, respectively (1). This anomaly is generally considered to be benign, and its recognition is advised in order to prevent surgical complications, such as accidental ligation or incision of the aberrant vessel. However, it was rarely thought to be responsible for "ischemic" complications in the absence of obstructive atherosclerosis (1-5). We previously described cases of angina pectoris and nonfatal myocardial infarction that probably were caused by this anomaly (3). The functional significance of this anomaly is further and more convincingly evidenced in the present autopsy case by the clinical and pathologic demonstration of a regional myocardial infarction in the territory depending on the anomalous LCx coronary artery, in the absence of significantly obstructive atherosclerosis. The pathogenesis of myocardial ischemia in the present case was most likely related to the oblique mode of ofigin of the anomalous coronary artery from the aorta. Indeed, this acute takeoff angle results in a slit-like coronary lumen and may induce a dynamic flap-like obstruction of the coronary ostium (1). Unlike other aberrant coronary arteries passing between the aorta and pulmonary trunk, there is no apparent risk of extrinsic compression because the LCx runs behind the aorta without having an intramural course. However, Murphy et al. reported acute myocardial infarction in a 12-year-old girl with angiographic evidence of systolic compression of the retroaortic portion of a left common coronary artery (6). Chaitman et al. reported acute myocardial infarction in the setting of the left coronary artery arising as the first branch of the fight coronary artery and coursing posterior to the aorta before dividing (7). In our patient, the fatal cardiac arrest one month after acute myocardial infarction might have been caused either by a further ischemic episode or by a malignant ventricular arrhythmia arising from the postinfarction scar. In conclusion, an LCx coronary artery originating from the fight sinus of Valsalva is not as benign as was previously thought, given that it may precipitate fatal myocardial ischemia, even in the absence of obstructive atherosclerosis. Although this condition can be readily diagnosed by crosssectional echocardiography (8), the detection of patients at risk of myocardial ischemia is still intriguing, because exercise testing and the thallium perfusion test do not appear to be reliable tools (2).
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B F i g u r e 2. (A) Gross view of the anomalous course of the left circumflex coronary artery, which runs behind the aorta and the noncoronary aortic sinus of Valsalva. (B) The same, at histology: note the presence of only 30% reduction in cross-sectional area by a concentric atherosclerosclerosis. (Azan stain, x 9.)
References 1, Roberts WC. Major anomalies of coronary arterial origin seen in adulthood. Am Heart J 1986;111:941-963. 2. Malajo AO, Bray CL, Prescott MC, Testa HJ. Thallium-201 myocardial imaging in patients with angina pectoris and anomalous origin of the circumflex coronary artery. Int J Cardiol 1988;18:371-381. 3. Piovesana P, Corrado D, Verlato R, et al. Morbidity associated with anomalous origin of the left circumflex coronary artery from the right aortic sinus. Am J Cardiol 1989;63:762-763. 4. Edelstein J, Jushasz RS. Myocardial infarction in the distribution of a patent anomalous left circumflex coronary artery. Cathet Cardiovasc Diagn 1984;10:171-175.
5. Patterson FK. Sudden death in young adult with anomalous origin of the posterior circumflex artery. South Med J 1982;75:748-751. 6. Murphy D, Roy D, Sohal M, Chandler B. Anomalous origin of the left main coronary artery from anterior sinus of Valsalva with myocardial infarction. J Thorac Cardiovasc Surg 1978:75:282-285. 7. Chairman B, Lesperance J, Saltiel J, Bourassa M. Clinical, angiographic, and hemodynamic findings in patients with anomalous origin of the coronary arteries. Circulation 1976;53:122-130. 8. Piovesana P, Corrado D, Contessotto F, et al. Echocardiographic identification of anomalous origin of the left circumflex coronary artery from the right aortic sinus of Valsalva. Am Heart J 1990; 119:205-207.
Cardiovasc Pathol Vol. 3, No. 4
October-December 1994:269-271
Anomalous Origin of the Left Circumflex Coronary Artery from the Right Aortic Sinus of Valsalva and Sudden Death D o m e n i c o Corrado, MD, Tommaso Pennelli, MD, PierGiuseppe Piovesana MD, and Gaetano Thiene, M D
Departments of Pathology and Cardiology, University of Padua Medical School, Padua, Italy
++ Anomalous origin of the left circumflex coronary artery from the right aortic sinus is generally considered a benign condition. We report a 53-year-old man with clinical and pathologic evidence of myocardial infarction and sudden death in the setting of this anomaly, with no evidence of obstructive coronary atherosclerosis.
Origin of the left circumflex (LCx) coronary artery from the right aortic coronary sinus, the most common congenital coronary anomaly (1), is generally considered an anatomic variant without clinical relevance; nonetheless, it has been found occasionally in association with angina pectoris (2,3), myocardial infarction (3,4), and sudden death (1,5), in the absence of obstructive atherosclerotic coronary artery disease. We report further clinical and pathologic evidence that an anomalous LCx coronary artery in itself may precipitate myocardial infarction and sudden death.
Case Report A 53-year-old man was admitted to the coronary care unit because of precordial pain of 10 hours' duration. The patient's medical history was unremarkable; he had neither significant coronary risk factors nor history of lung disease or anemia. At the time of symptoms onset, the patient was not engaged in exertion and had no fever that may have contributed to a myocardial oxygen supply/demand imbalance. Clinical examination revealed no cardiac murmurs; systolic blood pressui'e was 130 mmHg. Electrocardiographic (ECG) tracings showed an ST-segment elevation in leads L2, L3, aVF, V5, and V6, as well as an ST-segment depression from V1 to V4. The patient was treated with aspirin and continuous nitroglycerin infusion. Chest X-ray findings were normal, and crossThis work was supported by the Juvenile Sudden Death Research Project of the Veneto Region, Venice and by National Council for Research, Target Project FAT.MA., Rome, Italy. Manuscript received April 12, 1993; accepted February 15, 1994. Address for reprints: Gaetano Thiene, MD, Istituto di Anatomia Patologica, Via A. Gabelli, 61, 35121 Padova, Italy. © 1994 by Elsevier Science Inc.
sectional echocardiogram showed posterolateral left ventricular wall akinesia with preserved ejection fraction. Serial ECG and serum enzyme determinations confirmed the diagnosis of acute "non-Q wave" myocardial infarction. The peak creatine phosphokinase level was 1800 I.U., with a myocardial fraction of 630 I.U. The clinical course was uneventful, and the patient was discharged on aspirin (100 mg/day). One month later the patient was readmitted for follow-up evaluation; unexpectedly he was found dead in the hospital bathroom in the early morning.
Necropsy and Histological Findings Postmortem examination disclosed a heart weight of 400 g and no significant alterations in chamber size or wall thickness. All cardiac valves were normal. Careful examination of the major epicardial coronary arteries revealed a balanced pattern, and no signs of obstructive (>/70% cross-sectional area narrowing) coronary atherosclerotic disease. The LCx coronary artery took off at an acute angle from the anterior right aortic sinus, separately from the fight coronary ostium (Figure 1A), and ran behind the aorta without an intramural course to reach the left atrioventricular groove (Figure 2A). All the coronary ostia were patent and devoid of atherosclerosis. A healed myocardial infarction was detected and consisted of a large subendocardial scar in the posterolateral wall of the left ventricle (Figure 1B), in the tributary myocardium of the anomalous LCx coronary artery. Histology confirmed the absence of obstructive atherosclerotic coronary artery disease (Figure 2B) and the presence of a postinfarction subendocardial fibrosis. 1054-8807/94/$7.00
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CORRADO ET AL. ANOMALOUSORIGINOF LCX CORONARYARTERY
CardiovascPatholVol. 3, No, 4 October-December1994:269-271
Pathologic examination of all other organs ruled out any life-threatening lesions. Toxicologic analysis of blood and urine specimens was negative.
Discussion
Figure 1. (A) Gross view of the aortic root showing the anomalous origin of the left circumflex coronary artery from the fight coronary sinus with a separate ostium. The right coronary artery is cut longitudinally. The arrow indicates the left coronary ostium. Dotted lines depict the proximal retroaortic course of the anomalous coronary artery with an acute take-off. (B) Healed myocardial infarction located in the posterolateral free wall of the left ventricle: note the dominant left circumflex coronary artery, devoid of significantly obstructive atherosclerosis, running in the left atrioventricular groove.
Origin of the LCx coronary artery from the right aortic sinus of Valsalva or from the proximal right coronary artery is not a rare congenital anomaly; indeed, in previous angiographic and pathologic series, its incidence was 0.4 % and 0.7 %, respectively (1). This anomaly is generally considered to be benign, and its recognition is advised in order to prevent surgical complications, such as accidental ligation or incision of the aberrant vessel. However, it was rarely thought to be responsible for "ischemic" complications in the absence of obstructive atherosclerosis (1-5). We previously described cases of angina pectoris and nonfatal myocardial infarction that probably were caused by this anomaly (3). The functional significance of this anomaly is further and more convincingly evidenced in the present autopsy case by the clinical and pathologic demonstration of a regional myocardial infarction in the territory depending on the anomalous LCx coronary artery, in the absence of significantly obstructive atherosclerosis. The pathogenesis of myocardial ischemia in the present case was most likely related to the oblique mode of ofigin of the anomalous coronary artery from the aorta. Indeed, this acute takeoff angle results in a slit-like coronary lumen and may induce a dynamic flap-like obstruction of the coronary ostium (1). Unlike other aberrant coronary arteries passing between the aorta and pulmonary trunk, there is no apparent risk of extrinsic compression because the LCx runs behind the aorta without having an intramural course. However, Murphy et al. reported acute myocardial infarction in a 12-year-old girl with angiographic evidence of systolic compression of the retroaortic portion of a left common coronary artery (6). Chaitman et al. reported acute myocardial infarction in the setting of the left coronary artery arising as the first branch of the fight coronary artery and coursing posterior to the aorta before dividing (7). In our patient, the fatal cardiac arrest one month after acute myocardial infarction might have been caused either by a further ischemic episode or by a malignant ventricular arrhythmia arising from the postinfarction scar. In conclusion, an LCx coronary artery originating from the fight sinus of Valsalva is not as benign as was previously thought, given that it may precipitate fatal myocardial ischemia, even in the absence of obstructive atherosclerosis. Although this condition can be readily diagnosed by crosssectional echocardiography (8), the detection of patients at risk of myocardial ischemia is still intriguing, because exercise testing and the thallium perfusion test do not appear to be reliable tools (2).
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B F i g u r e 2. (A) Gross view of the anomalous course of the left circumflex coronary artery, which runs behind the aorta and the noncoronary aortic sinus of Valsalva. (B) The same, at histology: note the presence of only 30% reduction in cross-sectional area by a concentric atherosclerosclerosis. (Azan stain, x 9.)
References 1, Roberts WC. Major anomalies of coronary arterial origin seen in adulthood. Am Heart J 1986;111:941-963. 2. Malajo AO, Bray CL, Prescott MC, Testa HJ. Thallium-201 myocardial imaging in patients with angina pectoris and anomalous origin of the circumflex coronary artery. Int J Cardiol 1988;18:371-381. 3. Piovesana P, Corrado D, Verlato R, et al. Morbidity associated with anomalous origin of the left circumflex coronary artery from the right aortic sinus. Am J Cardiol 1989;63:762-763. 4. Edelstein J, Jushasz RS. Myocardial infarction in the distribution of a patent anomalous left circumflex coronary artery. Cathet Cardiovasc Diagn 1984;10:171-175.
5. Patterson FK. Sudden death in young adult with anomalous origin of the posterior circumflex artery. South Med J 1982;75:748-751. 6. Murphy D, Roy D, Sohal M, Chandler B. Anomalous origin of the left main coronary artery from anterior sinus of Valsalva with myocardial infarction. J Thorac Cardiovasc Surg 1978:75:282-285. 7. Chairman B, Lesperance J, Saltiel J, Bourassa M. Clinical, angiographic, and hemodynamic findings in patients with anomalous origin of the coronary arteries. Circulation 1976;53:122-130. 8. Piovesana P, Corrado D, Contessotto F, et al. Echocardiographic identification of anomalous origin of the left circumflex coronary artery from the right aortic sinus of Valsalva. Am Heart J 1990; 119:205-207.
