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Congenital ostial membrane of left main coronary artery
J THoRAc
CARDIOVASC SURG
81:338-346, 1981
Congenital ostial membrane of left main coronary artery Abnormalities of coronary artery development. origin. and distribution are being diagnosed and treated successfully with increasing frequency. This report describes the case histories of two patients with stenosis of the left main coronary artery caused by a congenital ostial membrane; both patients were successfully treated by operation. A similar abnormality has been reported only once in the literature. having been discovered at autopsy.
Miguel Josa, M.D., Gordon K. Danielson, M.D., William H. Weidman, M.D., and William D. Edwards, M.D., Rochester. Minn.
COngenital anomalies of the coronary arteries are not common and, until recently, have seldom been diagnosed during life. Currently, abnormalities of the origin and distribution of the coronary arteries, coronary artery fistulas, and congenital hypoplasia or atresia of the coronary arteries are being diagnosed and treated with increasing frequency. 1-5 This report presents the only two patients encountered at this institution with stenosis of the left main coronary artery caused by a congenital ostial membrane; both patients were successfully treated by operation. A similar abnormality has been discovered previously at autopsy. 6
Case reports CAS E 1. A 2-year-old boy was admitted to the Mayo Clinic on May 14, 1968. for evaluation of acyanotic congenital heart disease. His birth had been uneventful and he had grown and developed normally. History and physical findings led to the diagnosis of moderate aortic stenosis. Cardiac catheterization was performed when the patient was 4 years of age. Aortic valvular stenosis was demonstrated with a peak systolic gradient of 38 to 40 mm Hg at rest. He was physically active and asymptomatic until the age of 5 years, when he complained of chest pain and dyspnea after running short distances. No significant changes in physical examination were noted. The chest x-ray film demonstrated a prominent left ventricle with a cardiothoracic ratio of 0.45. There was regular sinus rhythm on the electrocardiogram (Fig. I) with a frontal plane QRS axis of + 70 degrees, a T axis of +60 degrees, and normal QRS voltages. There was no
From the Departments of Surgery and Pathology and Anatomy and the Division of Pediatric Cardiology, Mayo Clinic and Mayo Foundation, Rochester, Minn. 55901. Receivedfor publication July 8, 1980. Accepted for publication Aug. 4, 1980.
338
family history of coronary artery disease and the serum cholesterol, triglycerides, and lipoprotein electrophoresis were within normal limits. A treadmill exercise test was performed because of symptoms suggesting angina. When he was exercised for 3 minutes at 3 miles/hr and a 20% grade, the heart rate increased to 175 beats/min and he experienced severe substernal squeezing pain. The electrocardiogram recorded at 3 minutes showed J point depression of 2 mm with a flat ST segment persisting for 0.10 seconds in Leads I, II, «v., and V3 to V6 (Fig. 2). The heart rate decreased to 90 beats/min I minute after exercise and the chest pain disappeared after 2 minutes. Cardiac catheterization was repeated shortly thereafter (Table I). The cardiac indices, calculated by dye-dilution curve analysis, were 6.1 L'min/rn" and 7.3 L'min/rn", respectively, prior to and after infusion of isoproterenol, 0.04 mcg/rnin/m". The transvalvular peak systolic pressure gradient was 39 mm Hg at rest and 47 mm Hg after isoproterenol infusion. Left ventricular and aortic root biplane angiograms were done (Fig. 3). The left ventricle was slightly enlarged but contracted well. The aortic valve had slightly thickened cusps. There was a normal right coronary artery, mild poststenotic dilatation of the ascending aorta, no aortic valvular incompetence, and no evidence of idiopathic hypertrophic subaortic stenosis. Because the left coronary artery was poorly visualized, a selective injection was done. This was interpreted as showing a normal origin and distribution of the vessel (Fig. 4). Propranolol was started at a dose of 20 mg/day and then increased to 60 mg/day over the subsequent 2 months, without producing a decrease in his effort angina. An exercise treadmill test, repeated at the age of 7 years, showed a 3 to 4 mm ST-segment depression in Leads V~, Vo, and V6 when the patient was exercised for 8 minutes at 2 miles/hr and a 10% grade. An operation was then recommended to relieve the mild aortic valve stenosis and to explore for a possible ostial stenosis of the left coronary artery . Operative findings. Operation was performed on June 19, 1973. The left ventricle was moderately hypertrophied and there was a systolic thrill over the ascending aorta. The pres-
0022-5223/811030338+09$00.9010 © 1981 The C. V. Mosby Co.
Volume 81
Congenital ostial membrane of LMCA
Number 3 March,1981
339
Fig. I. Case 1. Normal preoperative electrocardiogram. sure in the right atrium was 7 mm Hg; in the right ventricle 25/5; in the left atrium 20/10; in the left ventricle 110/0; and in the aorta 80/65 mm Hg. The aortic intima was smooth and there were no degenerative changes suggestive of congenital syphilis. The aortic valve was tricuspid and the cusps were thickened and mildly nodular. The noncoronary and coronary cusps were fused posteriorly. No subvalvular stenosis was present. The left coronary artery arose from the left aortic sinus more to the right than usual. The ostium was only I mm in diameter, but it could easily be dilated up to 3 mm. When the dilators were removed, the orifice snapped back to a I mm diameter. This ostial stenosis was produced by a membranous structure that was continuous with the aortic intima. The membrane was excised and the orifice enlarged to 3 mm diameter. The ostial membrane was formed of intertwining elastic laminae with intervening collagen and smooth muscle cells (Fig. 5). Its structure was similar to that of the normal media of the aortic root. There was no evidence of inflammation or fibrosis. An aortic valvotomy completed the operation; postoperative pressures were 100/5 mm Hg in the left ventricle and 85/60 mm Hg in the aorta. The patient had an uneventful postoperative recovery and was dismissed from the hospital on the tenth postoperative day. A Grade 2/6 aortic systolic murmur was present. A repeat treadmill exercise test prior to dismissal was within normal limits (Fig. 6). Six years after operation he had an episode of bacterial endocarditis which responded to antibiotic therapy. Now, 7 years after operation, he is free of angina and is able to participate in sports. There is a Grade 3/6 systolic ejection
Table I. Cardiac catheterization data, Case 1 Site
Right atrium Right ventricle Pulmonary artery Pulmonary wedge Left ventricle Ascending aorta
I Pressure (mm Hg) 8/2 (m = 3) 36/2 30/13 17/6 (m = 9) 119/4-16 80/47
Oxygen sat. (%)
78 80 82 94
murmur at the upper right sternal border and a Grade 2/6 early diastolic murmur in the same area. Serial treadmill exercise tests have remained normal. * CAS E 2. An 8-year-old boy was admitted to the Mayo Clinic on April 19, 1979, for evaluation of acyanotic congenital heart disease. He had an uncomplicated birth, but congestive heart failure developed on the second day of life and he had been treated with a digitalis preparation since that time. Growth and development were delayed and he had easy fatigability and dyspnea. Cardiac catheterization at the age of 6 months suggested a diagnosis of ventricular septal defect with pulmonary hypertension. At operation, the diagnosis of truncus arteriosus type I was made. Banding the pulmonary trunk decreased the distal pressures from 70 to 30 mm Hg. His postoperative course was uneventful and he did well while receiving digitalis therapy. Cardiac catheterizations *Weare indebted to Dr. JamesMollerand Dr. MariDuncombe of the University of Minnesota for these follow-up data.
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Fig. 2. Case 1. Preoperative treadmill exercise electrocardiogram showing a J point depression of 2 mm and ST-segment depression. were repeated at the ages of 6 and 7 years; on both occasions the pulmonary artery band was reported as being very tight and pressure gradients could not be measured across it. At the time of our evaluation he had mild cyanosis and clubbing. The peripheral pulses were bounding, with rapid upstroke and descent. The left ventricular impulse was located at the sixth left intercostal space, and systolic thrills were palpable over the left lower sternal border and suprasternal notch. The first sound was normal and the second sound single. There was a Grade 4/6 harsh holosystolic murmur at the left lower sternal border radiating to both lung fields, a short Grade 2/6 blowing diastolic murmur at the mid left sternal border radiating to the apex, and a Grade 2/6 mid-diastolic murmur at the apex. The lungs were clear and the liver was not enlarged. The chest x-ray film showed enlargement of the heart, a left aortic arch, increased pulmonary vascular markings, and a prominent pulmonary artery. The hemoglobin value was 16 gm/dl and the hematocrit value 45%. The electrocardiogram
(Fig. 7) showed sinus rhythm with a PR interval of 0.16 second, large P waves, a frontal plane QRS axis of +80 degrees, and a T axis of +50 degrees; there was biventricular hypertrophy. Cardiac catheterization was performed (Table II). Pulmonary blood flow was 6.1 L'rnin/m" and systemic flow was 3.2 L'rnin/rn". Stenosis of both the right and left pulmonary arteries was confirmed, but elevation of right and left pulmonary arterial pressures was present. The total pulmonary resistance was 9.3 units and pulmonary arteriolar resistance was 7.5 units. The total pulmonary resistance decreased to 5.8 units when the patient breathed 100% oxygen. Aortic root and right ventricular angiograms demonstrated truncus arteriosus, ventricular septal defect, banding of the main pulmonary artery, and dilation of the distal right and left pulmonary arteries (Fig. 8). There was mild truncal valve incompetence. The left coronary artery was poorly visualized, but the coronary arterial distribution was interpreted as being normal. A sector echocardiogram confirmed the intracardiac findings.
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Fig. 3. Case I. Left ventricular angiogram. Left, Posteroanterior view. Right, Lateral view. The aortic valve has slightly thickened cusps. The left coronary artery is poorly visualized.
Table II. Cardiac catheterization data, Case 2 Oxygen sat. (%) Site
Inferior vena cava Superior vena cava Right atrium Right ventricle Right pulmonary artery Left pulmonary artery Pulmonary wedge Femoral artery
\100% oxygen
Pressure (mm Hg)
Room air
7/0 (m = 4) 111/9 63/51 (m = 59)
73 67 70 69 85
74/44 (m = 61)
85
97
13/8 (m = 10) 135/59 (m = 83)
90
98
76 97
Operative findings. Operation was performed on April 26, 1979. A large conal branch of the right coronary artery coursed over the heart directly anteriorly; the coronary arterial anatomy otherwise appeared normal. A pulmonary trunk 5 mm long and arising from the left posterolateral aspect of the truncus was narrowed at the bifurcation by the previously placed band. Distal to the band, both pulmonary arteries were of normal size. The truncal valve was bicuspid. The ventricular septal defect was typical for truncus arteriosus, having an inferior muscular rim; it was 1.8 by 1.2 em in diameter. The pressure in the right atrium was 5/2 mm Hg; in the right ventricle 100/0; in the right pulmonary artery 50/35; in the left pulmonary artery 80/50; in the left atrium 16/5; in the left ventricle 100/0; and in the femoral artery 120/65 mm Hg.
Fig. 4. Case I. Selective left coronary artery angiogram showing normal origin and distribution. The atrial septum was intact to palpation and the tricuspid valve was competent. During preliminary dissection, cardiac function suddenly deteriorated without obvious reason. The aorta was rapidly cannulated for arterial inflow from the pump, and venous
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342 Josa et al.
Fig. S. Case 1. Photomicrographs of stenosing membrane of left coronary ostium. Irregular herringbone, or mosaic, pattern of smooth muscle cells (a) and of collagen and elastin (b) is similar to media of normal aortic root. (A, Hematoxylin and eosin, x 100; B, elastic-van Gieson, x 100.)
z Fig. 6. Case I. Normal postoperative treadmill exercise electrocardiogram.
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Fig. 7. Case 2. Preoperative electrocardiogram showing left and right ventricular hypertrophy. cannulas were inserted into the superior and inferior venae cavae via the right atrial appendage. Extracorporeal circulation was instituted, the left side of the heart was vented through the right superior pulmonary vein, the perfusate temperature was lowered to 20° C, the truncus was cross-clamped for 67 minutes, and cardiac arrest was induced with an infusion of cold cardioplegic solution. The myocardial temperature was kept between 13.3° and 22.5° C by two additional infusions of cold cardioplegic solution at 20 minute intervals. The main pulmonary artery was excised from the truncus and the truncal defect was closed with a double running suture. An incision was made in the right ventricular outflow tract and the ventricular septal defect was closed with a patch. A 25 mm Hancock conduit with a porcine valve was used to establish continuity between the right ventricle and the right and left pulmonary arteries. After rewarming was accomplished, sinus rhythm returned spontaneously. However, the left ventricle had very poor contractions and the left atrial pressure increased to 40 to 50 mm Hg whenever a volume load was placed on the ventricle. Ventricular fibrillation developed several times, and several countershocks and an infusion of lidocaine were needed to restore sinus rhythm. The left ventricle became akinetic while the right ventricle maintained a good contraction. Careful inspection disclosed no compression of any coronary artery by the conduit rior injury by a suture line. Because we suspected obstruction of the proximal left coronary artery by an embolus, the perfusate temperature was lowered again, the aorta was cross-clamped for 12 minutes, and an aortotomy was performed. A No. 3 Fogarty balloon catheter was inserted through the left coronary ostium and advanced nearly
to the apex. When the catheter was withdrawn, no embolus was retrieved. However, the balloon pulled up a membrane at the level of the ostium which was narrowing the lumen to a diameter of I mm. This membrane was resected so that the lumen diameter was increased to 5 mm. A 5 mm probe then was passed easily into the distal left coronary artery. After repair of the aorta and rewarming, left ventricular contractions became vigorous, sinus rhythm was easily maintained, hemodynamics were satisfactory, and extracorporeal circulation was discontinued without difficulty. The patient had an uneventful postoperative recovery and was dismissed from the hospital on the tenth postoperative day. There were no signs of myocardial ischemia either clinically or by electrocardiography. Follow-up information from the patient's cardiologists* and a telephone conversation with his parents 13 months after operation indicate that he has no cardiac symptoms, specifically no chest pain with exertion, and he is physically active and able to keep up with his peers. His growth has been good and he is doing well academically in school.
Comment
Anomalies of the origin of the coronary arteries are being reported with increasing frequency. Engel, Torres, and Page? found a 1.2% incidence of major variations in the anatomic origin of the coronary arteries in *We are indebted to Professor D. Wolf and Dr. Almer of the University of Heidelberg for these data.
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Fig. 8. Case 2. Truncal root angiogram. Left. Posteroanterior view. Right. Lateral view. Mild truncal valve insufficiency is present. The left coronary artery is poorly visualized.
4,250 angiograms of patients without associated congenital heart disease. The incidence of various coronary artery anomalies is even higher in patients with congenital heart disease. 8-12 Hypoplasia or atresia of the coronary arteries in infancy and childhood is an uncommon problem; however, when present, these anomalies often cause severe impairment of ventricular function and sudden death." 6. 13 Congenital atresia of the left main coronary artery has been reported in nine patients, all of whom presented with signs and symptoms of myocardial ischemia, congestive heart failure, or both. I - 3 • 13-15 Histopathological studies in these patients showed that the left main coronary artery was replaced by a fibromuscular cord and the left coronary artery ostium was absent or occluded. 13-15 Supravalvular aortic stenosis often is associated with pathological changes in the coronary arteries resulting from abnormal hemodynamic conditions within the arteries which lead to structural changes in their walls. In addition, supravalvular aortic stenosis has been reported in association with atresia of the proximal left main coronary artery and with occlusion of the ostium of a coronary artery; the occlusion is due to fusion of the free edge of an aortic valve cusp to the area of aortic narrowing distal to the ostium of the involved coronary artery 3. IS. 16 Chernausek and associates 17 described the case of a 3-day-old infant who died of truncus ar-
teriosus complicated by stenosis of the main left coronary artery. The stenosis was not membranous, but extended through the full thickness of the truncal wall; it was attributed to dysplastic changes in the wall thought to be a forme fruste of supravalvular aortic stenosis. Aside from congenital developmental abnormalities of the coronary arteries, several uncommon acquired processes such as medial calcification and intimal proliferation, polyarteritis nodosa, atherosclerosis, syphilitic arteritis, embolism, rheumatic arteritis, and hypertension may cause stenosis or occlusion of coronary arteries in children. 16. 18-23 In syphilis, the coronary arteries are generally narrowed or occluded at the ostium as part of a syphilitic involvement of the ascending aorta. In these patients, the characteristic changes of the aortic wall, other stigmata of congenital syphilis, and positive serologic tests in the parents clarify the cause of the process. 16. 19. 23 The two cases reported here did not have clinical or pathological evidence of any of these acquired diseases. Furthermore, histologic studies in Case I show that the structure of the ostial membrane is similar to that of the normal aortic root, and it seems reasonable to conclude that the membrane is a developmental anomaly. Embryologically, coronary arteries develop from thickenings in the aortic endothelium which first form solid cords that subsequently canalize;" It has
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Congenital ostial membrane of LMCA
Number 3 March,1981
been suggested that atresia of the left main coronary artery might be due to a failure of this canalization process." The anomaly we are reporting may have a similar cause, i.e., an incomplete process of canalization which leaves a membranous obstruction at the orifice of the coronary artery. Verney and associates" reported the case of an infant who was first seen at the age of 4 months with signs and symptoms of heart failure and moderately severe mitral incompetence. The electrocardiogram showed severe anterolateral myocardial ischemia. An aortic root angiogram demonstrated the right coronary artery satisfactorily but failed to visualize the left coronary artery. The patient's condition deteriorated rapidly and the child died at the age of 6V2 months. At postmortem examination, the left coronary artery ostium was found to be 0.5 mm in diameter. The coronary arteries were otherwise normal, both in size and distribution, and there were no anatomic abnormalities of the mitral valve other than a dilated anulus. An area of myocardial infarction was present anterolaterally. This patient did not have any other anatomic reason for myocardial ischemia and infarction, and the malformation was similar to the ones in this report. However, it is not clear whether the stenosis was membranous, as in our two patients, or whether it constituted the entire intramural length of the coronary artery, as in the case reported by Chernausek and associates." Exercise stress tests performed in children with congenital aortic stenosis have shown that a severe degree of aortic obstruction is frequently associated with exercise-induced ischemic changes on the electrocardiograrn.P: 26 It would be unusual for patients with resting gradients under 50 mm Hg to have significant ST-segment depression during exercise testing. In Case 1, the ostial membrane was associated with congenital aortic stenosis and a resting peak systolic pressure gradient of 40 mm Hg. However, the patient had angina, dyspnea, and significant ST-segment depression with exercise. Because there was this discrepancy between the severity of his anginal symptoms and electrocardiographic changes compared with the severity of his aortic stenosis, a coronary artery anomaly was suspected. An aortic root injection failed to visualize the left coronary artery satisfactorily, but a selective injection showed a normal appearance and distribution of the artery because the catheter displaced the obstructing ostial membrane. Despite the report of normal coronary arterial anatomy, surgical exploration of the aortic root was performed and was successful in identifying an obstructing membrane. Relief of symptoms followed resection of the membrane. Under similar cir-
345
cumstances in which there is a discrepancy between the hemodynamic findings and the symptoms in patients with aortic stenosis, a high index of suspicion of ostial membrane should be maintained, and an aortic root exploration may be indicated, even when an aortic root angiogram or selective coronary arteriogram shows normal arteries. The second patient did not have preoperative symptoms of angina or electrocardiographic signs of ischemia. Both coronary arteries were visualized in the aortic root injection and were interpreted as being normal, although, in retrospect, the left coronary artery visualized only faintly. It is uncertain how much the coronary artery anomaly contributed to the patient's chronic heart failure and to the cardiac arrest during preliminary dissection of the heart. However, it is clear that the ostial stenosis became functionally significant after discontinuation of extracorporeal circulation when ventricular ectopia and isolated failure of the left ventricle developed. Both of these were relieved when the ostial membrane was excised. Isolated failure of a segment of myocardium in the distribution of a major coronary artery at the conclusion of extracorporeal circulation should raise the suspicion of an obstructing ostial membrane as well as possible embolism, dissection, or other acute coronary artery obstruction which can be diagnosed and treated via an aortic root exploration. Congenital coronary arterial stenosis or atresia is an uncommon anomaly. However, when present, it often causes severe impairment of ventricular function or sudden death. Careful evaluation of the origin and distribution of the coronary arteries is necessary in patients with congenital heart disease when the signs and symptoms of ischemia and heart failure are disproportionate to other disease present. In older children, an exercise stress test may be of help in the diagnosis.
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4
5
REFERENCES Levin DC, Fellows KE, Abrahams HL: Hemodynamically significant primary anomalies of the coronary arteries. Circulation 58:25, 1978 Mullins CE, EI-Said G, McNamara DG, et al: Atresia of the left coronary arteryostium. Repairby saphenous vein graft. Circulation 46:989, 1972 Allen HD, Moller JH, Formanek A, Nicoloff D: Atresia of the proximal left coronary artery associated with supravalvular aortic stenosis. J THORAC CARDIOVASC SURG 67:226, 1974 Kimbiris DK, Iskandrian AS, Segal BL, Bemis CE: Anomalous aortic origin of coronary arteries. Circulation 58:606, 1978 Liberthson RR, Dinsmore RE, Fallon JT: Aberrant coronary artery origin from the aorta. Report of 18 patients,
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review of literature and delineation of natural history and management. Circulation 59:748, 1979 6 Verney RN, Monnet P, Arnaud P, et al: Infarctus du myocarde chez un nourrisson de cino mois-ostium coronaire gauche punctiforme. Ann Pediatr (Paris) 16:
260, 1969 7 Engel HJ, Torres C, Page HL: Major variations in anatomical origin of the coronary arteries. Angiographic observations in 4,250 patients without associated congenital heart disease. Cathet Cardiovasc Diagn 1: 157,
1975 8 Meng CCL, Eckner FAO, Lev M: Coronary artery distribution in tetralogy of Fallot. Arch Surg 90:363, 1965 9 Berry BE, McGoon DC: Total correction for tetralogy of Fallot with anomalous coronary artery. Surgery 74:894,
1973 10 Anderson KR, McGoon DC, Lie JT: Surgical significance of the coronary arterial anatomy in truncus arteriosus communis. Am J Cardiol 41:76, 1978 II Shaher RM, Paddu GC: Coronary arterial anatomy in complete transposition of the great vessels. Am J Cardiol
17:355, 1966 12 Keeton BR, Lie JT, McGoon DC, Danielson GK, Ritter 00, Wallace RB: Anatomy of coronary arteries in univentricular hearts and its surgical implications. Am J Cardiol 43:569, 1979 13 Fortuin NJ, Roberts NC: Congenital atresia of the left main coronary artery. Am J Med 50:385, 1971 14 Vidne BA, Nili M, Aygen M, Levy MJ: Congenital atresia of the left main coronary artery ostium. Scand J Thorac Cardiovasc Surg 13:37, 1979
Thoracic and Cardiovascular Surgery
15 Price AC, Lee DA, Kagan KE, Baker WP: Aortic dysplasia in infancy simulating anomalous origin of the left coronary artery. Circulation 48:434, 1973 16 Stryker WA: Coronary occlusive disease in infants and children. Am J Dis Child 77:280, 1946 17 Chernausek SD, Swan DC, Moller JH, Vlodaver Z, Edwards JE: Clinical pathologic conference. Am Heart J
91:249, 1976 18 Peterson T A, Todd DB, Edwards JE: Supravalvular aortic stenosis. J THoRAc CARDIOVASC SURG 50:734, 1965 19 Norris RF: Syphilis aortitis in childhood and youth. Report of two cases with sudden death. Johns Hopkins Med
J 57:206, 1935 20 McDonald S Jr: Syphilitic aortitis in young adults with special reference to a congenital etiology. Br J Vener Dis
10:183, 1934 21 McMahon HE, Dickinson PC: Occlusive fibroelastosis of coronary arteries in the newborn. Circulation 35:3, 1967 22 Chipman CD: Calcific stenosis of coronary arteries in infancy. Can Med Assoc J 83:955, 1960 23 Goormaghtigh N, De Vos L, Blancpuaert A: Ostial stenosis of coronary arteries in nine year old girl. Arch Intern Med 95:341,1955 24 Grant RT: Development of the cardiac coronary artery vessels in the rabbit. Heart 13:261, 1926 25 Halloran KH: The telemetered exercise electrocardiogram in congenital aortic stenosis. Pediatrics 47:31,1971 26 Chandramouli B, Ehmke DA, Lauer RM: Exerciseinduced electrocardiographic changes in children with congenital aortic stenosis. J Pediatr 87:725, 1975
CARDIOVASC SURG
81:338-346, 1981
Congenital ostial membrane of left main coronary artery Abnormalities of coronary artery development. origin. and distribution are being diagnosed and treated successfully with increasing frequency. This report describes the case histories of two patients with stenosis of the left main coronary artery caused by a congenital ostial membrane; both patients were successfully treated by operation. A similar abnormality has been reported only once in the literature. having been discovered at autopsy.
Miguel Josa, M.D., Gordon K. Danielson, M.D., William H. Weidman, M.D., and William D. Edwards, M.D., Rochester. Minn.
COngenital anomalies of the coronary arteries are not common and, until recently, have seldom been diagnosed during life. Currently, abnormalities of the origin and distribution of the coronary arteries, coronary artery fistulas, and congenital hypoplasia or atresia of the coronary arteries are being diagnosed and treated with increasing frequency. 1-5 This report presents the only two patients encountered at this institution with stenosis of the left main coronary artery caused by a congenital ostial membrane; both patients were successfully treated by operation. A similar abnormality has been discovered previously at autopsy. 6
Case reports CAS E 1. A 2-year-old boy was admitted to the Mayo Clinic on May 14, 1968. for evaluation of acyanotic congenital heart disease. His birth had been uneventful and he had grown and developed normally. History and physical findings led to the diagnosis of moderate aortic stenosis. Cardiac catheterization was performed when the patient was 4 years of age. Aortic valvular stenosis was demonstrated with a peak systolic gradient of 38 to 40 mm Hg at rest. He was physically active and asymptomatic until the age of 5 years, when he complained of chest pain and dyspnea after running short distances. No significant changes in physical examination were noted. The chest x-ray film demonstrated a prominent left ventricle with a cardiothoracic ratio of 0.45. There was regular sinus rhythm on the electrocardiogram (Fig. I) with a frontal plane QRS axis of + 70 degrees, a T axis of +60 degrees, and normal QRS voltages. There was no
From the Departments of Surgery and Pathology and Anatomy and the Division of Pediatric Cardiology, Mayo Clinic and Mayo Foundation, Rochester, Minn. 55901. Receivedfor publication July 8, 1980. Accepted for publication Aug. 4, 1980.
338
family history of coronary artery disease and the serum cholesterol, triglycerides, and lipoprotein electrophoresis were within normal limits. A treadmill exercise test was performed because of symptoms suggesting angina. When he was exercised for 3 minutes at 3 miles/hr and a 20% grade, the heart rate increased to 175 beats/min and he experienced severe substernal squeezing pain. The electrocardiogram recorded at 3 minutes showed J point depression of 2 mm with a flat ST segment persisting for 0.10 seconds in Leads I, II, «v., and V3 to V6 (Fig. 2). The heart rate decreased to 90 beats/min I minute after exercise and the chest pain disappeared after 2 minutes. Cardiac catheterization was repeated shortly thereafter (Table I). The cardiac indices, calculated by dye-dilution curve analysis, were 6.1 L'min/rn" and 7.3 L'min/rn", respectively, prior to and after infusion of isoproterenol, 0.04 mcg/rnin/m". The transvalvular peak systolic pressure gradient was 39 mm Hg at rest and 47 mm Hg after isoproterenol infusion. Left ventricular and aortic root biplane angiograms were done (Fig. 3). The left ventricle was slightly enlarged but contracted well. The aortic valve had slightly thickened cusps. There was a normal right coronary artery, mild poststenotic dilatation of the ascending aorta, no aortic valvular incompetence, and no evidence of idiopathic hypertrophic subaortic stenosis. Because the left coronary artery was poorly visualized, a selective injection was done. This was interpreted as showing a normal origin and distribution of the vessel (Fig. 4). Propranolol was started at a dose of 20 mg/day and then increased to 60 mg/day over the subsequent 2 months, without producing a decrease in his effort angina. An exercise treadmill test, repeated at the age of 7 years, showed a 3 to 4 mm ST-segment depression in Leads V~, Vo, and V6 when the patient was exercised for 8 minutes at 2 miles/hr and a 10% grade. An operation was then recommended to relieve the mild aortic valve stenosis and to explore for a possible ostial stenosis of the left coronary artery . Operative findings. Operation was performed on June 19, 1973. The left ventricle was moderately hypertrophied and there was a systolic thrill over the ascending aorta. The pres-
0022-5223/811030338+09$00.9010 © 1981 The C. V. Mosby Co.
Volume 81
Congenital ostial membrane of LMCA
Number 3 March,1981
339
Fig. I. Case 1. Normal preoperative electrocardiogram. sure in the right atrium was 7 mm Hg; in the right ventricle 25/5; in the left atrium 20/10; in the left ventricle 110/0; and in the aorta 80/65 mm Hg. The aortic intima was smooth and there were no degenerative changes suggestive of congenital syphilis. The aortic valve was tricuspid and the cusps were thickened and mildly nodular. The noncoronary and coronary cusps were fused posteriorly. No subvalvular stenosis was present. The left coronary artery arose from the left aortic sinus more to the right than usual. The ostium was only I mm in diameter, but it could easily be dilated up to 3 mm. When the dilators were removed, the orifice snapped back to a I mm diameter. This ostial stenosis was produced by a membranous structure that was continuous with the aortic intima. The membrane was excised and the orifice enlarged to 3 mm diameter. The ostial membrane was formed of intertwining elastic laminae with intervening collagen and smooth muscle cells (Fig. 5). Its structure was similar to that of the normal media of the aortic root. There was no evidence of inflammation or fibrosis. An aortic valvotomy completed the operation; postoperative pressures were 100/5 mm Hg in the left ventricle and 85/60 mm Hg in the aorta. The patient had an uneventful postoperative recovery and was dismissed from the hospital on the tenth postoperative day. A Grade 2/6 aortic systolic murmur was present. A repeat treadmill exercise test prior to dismissal was within normal limits (Fig. 6). Six years after operation he had an episode of bacterial endocarditis which responded to antibiotic therapy. Now, 7 years after operation, he is free of angina and is able to participate in sports. There is a Grade 3/6 systolic ejection
Table I. Cardiac catheterization data, Case 1 Site
Right atrium Right ventricle Pulmonary artery Pulmonary wedge Left ventricle Ascending aorta
I Pressure (mm Hg) 8/2 (m = 3) 36/2 30/13 17/6 (m = 9) 119/4-16 80/47
Oxygen sat. (%)
78 80 82 94
murmur at the upper right sternal border and a Grade 2/6 early diastolic murmur in the same area. Serial treadmill exercise tests have remained normal. * CAS E 2. An 8-year-old boy was admitted to the Mayo Clinic on April 19, 1979, for evaluation of acyanotic congenital heart disease. He had an uncomplicated birth, but congestive heart failure developed on the second day of life and he had been treated with a digitalis preparation since that time. Growth and development were delayed and he had easy fatigability and dyspnea. Cardiac catheterization at the age of 6 months suggested a diagnosis of ventricular septal defect with pulmonary hypertension. At operation, the diagnosis of truncus arteriosus type I was made. Banding the pulmonary trunk decreased the distal pressures from 70 to 30 mm Hg. His postoperative course was uneventful and he did well while receiving digitalis therapy. Cardiac catheterizations *Weare indebted to Dr. JamesMollerand Dr. MariDuncombe of the University of Minnesota for these follow-up data.
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Fig. 2. Case 1. Preoperative treadmill exercise electrocardiogram showing a J point depression of 2 mm and ST-segment depression. were repeated at the ages of 6 and 7 years; on both occasions the pulmonary artery band was reported as being very tight and pressure gradients could not be measured across it. At the time of our evaluation he had mild cyanosis and clubbing. The peripheral pulses were bounding, with rapid upstroke and descent. The left ventricular impulse was located at the sixth left intercostal space, and systolic thrills were palpable over the left lower sternal border and suprasternal notch. The first sound was normal and the second sound single. There was a Grade 4/6 harsh holosystolic murmur at the left lower sternal border radiating to both lung fields, a short Grade 2/6 blowing diastolic murmur at the mid left sternal border radiating to the apex, and a Grade 2/6 mid-diastolic murmur at the apex. The lungs were clear and the liver was not enlarged. The chest x-ray film showed enlargement of the heart, a left aortic arch, increased pulmonary vascular markings, and a prominent pulmonary artery. The hemoglobin value was 16 gm/dl and the hematocrit value 45%. The electrocardiogram
(Fig. 7) showed sinus rhythm with a PR interval of 0.16 second, large P waves, a frontal plane QRS axis of +80 degrees, and a T axis of +50 degrees; there was biventricular hypertrophy. Cardiac catheterization was performed (Table II). Pulmonary blood flow was 6.1 L'rnin/m" and systemic flow was 3.2 L'rnin/rn". Stenosis of both the right and left pulmonary arteries was confirmed, but elevation of right and left pulmonary arterial pressures was present. The total pulmonary resistance was 9.3 units and pulmonary arteriolar resistance was 7.5 units. The total pulmonary resistance decreased to 5.8 units when the patient breathed 100% oxygen. Aortic root and right ventricular angiograms demonstrated truncus arteriosus, ventricular septal defect, banding of the main pulmonary artery, and dilation of the distal right and left pulmonary arteries (Fig. 8). There was mild truncal valve incompetence. The left coronary artery was poorly visualized, but the coronary arterial distribution was interpreted as being normal. A sector echocardiogram confirmed the intracardiac findings.
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Fig. 3. Case I. Left ventricular angiogram. Left, Posteroanterior view. Right, Lateral view. The aortic valve has slightly thickened cusps. The left coronary artery is poorly visualized.
Table II. Cardiac catheterization data, Case 2 Oxygen sat. (%) Site
Inferior vena cava Superior vena cava Right atrium Right ventricle Right pulmonary artery Left pulmonary artery Pulmonary wedge Femoral artery
\100% oxygen
Pressure (mm Hg)
Room air
7/0 (m = 4) 111/9 63/51 (m = 59)
73 67 70 69 85
74/44 (m = 61)
85
97
13/8 (m = 10) 135/59 (m = 83)
90
98
76 97
Operative findings. Operation was performed on April 26, 1979. A large conal branch of the right coronary artery coursed over the heart directly anteriorly; the coronary arterial anatomy otherwise appeared normal. A pulmonary trunk 5 mm long and arising from the left posterolateral aspect of the truncus was narrowed at the bifurcation by the previously placed band. Distal to the band, both pulmonary arteries were of normal size. The truncal valve was bicuspid. The ventricular septal defect was typical for truncus arteriosus, having an inferior muscular rim; it was 1.8 by 1.2 em in diameter. The pressure in the right atrium was 5/2 mm Hg; in the right ventricle 100/0; in the right pulmonary artery 50/35; in the left pulmonary artery 80/50; in the left atrium 16/5; in the left ventricle 100/0; and in the femoral artery 120/65 mm Hg.
Fig. 4. Case I. Selective left coronary artery angiogram showing normal origin and distribution. The atrial septum was intact to palpation and the tricuspid valve was competent. During preliminary dissection, cardiac function suddenly deteriorated without obvious reason. The aorta was rapidly cannulated for arterial inflow from the pump, and venous
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Fig. S. Case 1. Photomicrographs of stenosing membrane of left coronary ostium. Irregular herringbone, or mosaic, pattern of smooth muscle cells (a) and of collagen and elastin (b) is similar to media of normal aortic root. (A, Hematoxylin and eosin, x 100; B, elastic-van Gieson, x 100.)
z Fig. 6. Case I. Normal postoperative treadmill exercise electrocardiogram.
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Fig. 7. Case 2. Preoperative electrocardiogram showing left and right ventricular hypertrophy. cannulas were inserted into the superior and inferior venae cavae via the right atrial appendage. Extracorporeal circulation was instituted, the left side of the heart was vented through the right superior pulmonary vein, the perfusate temperature was lowered to 20° C, the truncus was cross-clamped for 67 minutes, and cardiac arrest was induced with an infusion of cold cardioplegic solution. The myocardial temperature was kept between 13.3° and 22.5° C by two additional infusions of cold cardioplegic solution at 20 minute intervals. The main pulmonary artery was excised from the truncus and the truncal defect was closed with a double running suture. An incision was made in the right ventricular outflow tract and the ventricular septal defect was closed with a patch. A 25 mm Hancock conduit with a porcine valve was used to establish continuity between the right ventricle and the right and left pulmonary arteries. After rewarming was accomplished, sinus rhythm returned spontaneously. However, the left ventricle had very poor contractions and the left atrial pressure increased to 40 to 50 mm Hg whenever a volume load was placed on the ventricle. Ventricular fibrillation developed several times, and several countershocks and an infusion of lidocaine were needed to restore sinus rhythm. The left ventricle became akinetic while the right ventricle maintained a good contraction. Careful inspection disclosed no compression of any coronary artery by the conduit rior injury by a suture line. Because we suspected obstruction of the proximal left coronary artery by an embolus, the perfusate temperature was lowered again, the aorta was cross-clamped for 12 minutes, and an aortotomy was performed. A No. 3 Fogarty balloon catheter was inserted through the left coronary ostium and advanced nearly
to the apex. When the catheter was withdrawn, no embolus was retrieved. However, the balloon pulled up a membrane at the level of the ostium which was narrowing the lumen to a diameter of I mm. This membrane was resected so that the lumen diameter was increased to 5 mm. A 5 mm probe then was passed easily into the distal left coronary artery. After repair of the aorta and rewarming, left ventricular contractions became vigorous, sinus rhythm was easily maintained, hemodynamics were satisfactory, and extracorporeal circulation was discontinued without difficulty. The patient had an uneventful postoperative recovery and was dismissed from the hospital on the tenth postoperative day. There were no signs of myocardial ischemia either clinically or by electrocardiography. Follow-up information from the patient's cardiologists* and a telephone conversation with his parents 13 months after operation indicate that he has no cardiac symptoms, specifically no chest pain with exertion, and he is physically active and able to keep up with his peers. His growth has been good and he is doing well academically in school.
Comment
Anomalies of the origin of the coronary arteries are being reported with increasing frequency. Engel, Torres, and Page? found a 1.2% incidence of major variations in the anatomic origin of the coronary arteries in *We are indebted to Professor D. Wolf and Dr. Almer of the University of Heidelberg for these data.
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Fig. 8. Case 2. Truncal root angiogram. Left. Posteroanterior view. Right. Lateral view. Mild truncal valve insufficiency is present. The left coronary artery is poorly visualized.
4,250 angiograms of patients without associated congenital heart disease. The incidence of various coronary artery anomalies is even higher in patients with congenital heart disease. 8-12 Hypoplasia or atresia of the coronary arteries in infancy and childhood is an uncommon problem; however, when present, these anomalies often cause severe impairment of ventricular function and sudden death." 6. 13 Congenital atresia of the left main coronary artery has been reported in nine patients, all of whom presented with signs and symptoms of myocardial ischemia, congestive heart failure, or both. I - 3 • 13-15 Histopathological studies in these patients showed that the left main coronary artery was replaced by a fibromuscular cord and the left coronary artery ostium was absent or occluded. 13-15 Supravalvular aortic stenosis often is associated with pathological changes in the coronary arteries resulting from abnormal hemodynamic conditions within the arteries which lead to structural changes in their walls. In addition, supravalvular aortic stenosis has been reported in association with atresia of the proximal left main coronary artery and with occlusion of the ostium of a coronary artery; the occlusion is due to fusion of the free edge of an aortic valve cusp to the area of aortic narrowing distal to the ostium of the involved coronary artery 3. IS. 16 Chernausek and associates 17 described the case of a 3-day-old infant who died of truncus ar-
teriosus complicated by stenosis of the main left coronary artery. The stenosis was not membranous, but extended through the full thickness of the truncal wall; it was attributed to dysplastic changes in the wall thought to be a forme fruste of supravalvular aortic stenosis. Aside from congenital developmental abnormalities of the coronary arteries, several uncommon acquired processes such as medial calcification and intimal proliferation, polyarteritis nodosa, atherosclerosis, syphilitic arteritis, embolism, rheumatic arteritis, and hypertension may cause stenosis or occlusion of coronary arteries in children. 16. 18-23 In syphilis, the coronary arteries are generally narrowed or occluded at the ostium as part of a syphilitic involvement of the ascending aorta. In these patients, the characteristic changes of the aortic wall, other stigmata of congenital syphilis, and positive serologic tests in the parents clarify the cause of the process. 16. 19. 23 The two cases reported here did not have clinical or pathological evidence of any of these acquired diseases. Furthermore, histologic studies in Case I show that the structure of the ostial membrane is similar to that of the normal aortic root, and it seems reasonable to conclude that the membrane is a developmental anomaly. Embryologically, coronary arteries develop from thickenings in the aortic endothelium which first form solid cords that subsequently canalize;" It has
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been suggested that atresia of the left main coronary artery might be due to a failure of this canalization process." The anomaly we are reporting may have a similar cause, i.e., an incomplete process of canalization which leaves a membranous obstruction at the orifice of the coronary artery. Verney and associates" reported the case of an infant who was first seen at the age of 4 months with signs and symptoms of heart failure and moderately severe mitral incompetence. The electrocardiogram showed severe anterolateral myocardial ischemia. An aortic root angiogram demonstrated the right coronary artery satisfactorily but failed to visualize the left coronary artery. The patient's condition deteriorated rapidly and the child died at the age of 6V2 months. At postmortem examination, the left coronary artery ostium was found to be 0.5 mm in diameter. The coronary arteries were otherwise normal, both in size and distribution, and there were no anatomic abnormalities of the mitral valve other than a dilated anulus. An area of myocardial infarction was present anterolaterally. This patient did not have any other anatomic reason for myocardial ischemia and infarction, and the malformation was similar to the ones in this report. However, it is not clear whether the stenosis was membranous, as in our two patients, or whether it constituted the entire intramural length of the coronary artery, as in the case reported by Chernausek and associates." Exercise stress tests performed in children with congenital aortic stenosis have shown that a severe degree of aortic obstruction is frequently associated with exercise-induced ischemic changes on the electrocardiograrn.P: 26 It would be unusual for patients with resting gradients under 50 mm Hg to have significant ST-segment depression during exercise testing. In Case 1, the ostial membrane was associated with congenital aortic stenosis and a resting peak systolic pressure gradient of 40 mm Hg. However, the patient had angina, dyspnea, and significant ST-segment depression with exercise. Because there was this discrepancy between the severity of his anginal symptoms and electrocardiographic changes compared with the severity of his aortic stenosis, a coronary artery anomaly was suspected. An aortic root injection failed to visualize the left coronary artery satisfactorily, but a selective injection showed a normal appearance and distribution of the artery because the catheter displaced the obstructing ostial membrane. Despite the report of normal coronary arterial anatomy, surgical exploration of the aortic root was performed and was successful in identifying an obstructing membrane. Relief of symptoms followed resection of the membrane. Under similar cir-
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cumstances in which there is a discrepancy between the hemodynamic findings and the symptoms in patients with aortic stenosis, a high index of suspicion of ostial membrane should be maintained, and an aortic root exploration may be indicated, even when an aortic root angiogram or selective coronary arteriogram shows normal arteries. The second patient did not have preoperative symptoms of angina or electrocardiographic signs of ischemia. Both coronary arteries were visualized in the aortic root injection and were interpreted as being normal, although, in retrospect, the left coronary artery visualized only faintly. It is uncertain how much the coronary artery anomaly contributed to the patient's chronic heart failure and to the cardiac arrest during preliminary dissection of the heart. However, it is clear that the ostial stenosis became functionally significant after discontinuation of extracorporeal circulation when ventricular ectopia and isolated failure of the left ventricle developed. Both of these were relieved when the ostial membrane was excised. Isolated failure of a segment of myocardium in the distribution of a major coronary artery at the conclusion of extracorporeal circulation should raise the suspicion of an obstructing ostial membrane as well as possible embolism, dissection, or other acute coronary artery obstruction which can be diagnosed and treated via an aortic root exploration. Congenital coronary arterial stenosis or atresia is an uncommon anomaly. However, when present, it often causes severe impairment of ventricular function or sudden death. Careful evaluation of the origin and distribution of the coronary arteries is necessary in patients with congenital heart disease when the signs and symptoms of ischemia and heart failure are disproportionate to other disease present. In older children, an exercise stress test may be of help in the diagnosis.
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4
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REFERENCES Levin DC, Fellows KE, Abrahams HL: Hemodynamically significant primary anomalies of the coronary arteries. Circulation 58:25, 1978 Mullins CE, EI-Said G, McNamara DG, et al: Atresia of the left coronary arteryostium. Repairby saphenous vein graft. Circulation 46:989, 1972 Allen HD, Moller JH, Formanek A, Nicoloff D: Atresia of the proximal left coronary artery associated with supravalvular aortic stenosis. J THORAC CARDIOVASC SURG 67:226, 1974 Kimbiris DK, Iskandrian AS, Segal BL, Bemis CE: Anomalous aortic origin of coronary arteries. Circulation 58:606, 1978 Liberthson RR, Dinsmore RE, Fallon JT: Aberrant coronary artery origin from the aorta. Report of 18 patients,
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review of literature and delineation of natural history and management. Circulation 59:748, 1979 6 Verney RN, Monnet P, Arnaud P, et al: Infarctus du myocarde chez un nourrisson de cino mois-ostium coronaire gauche punctiforme. Ann Pediatr (Paris) 16:
260, 1969 7 Engel HJ, Torres C, Page HL: Major variations in anatomical origin of the coronary arteries. Angiographic observations in 4,250 patients without associated congenital heart disease. Cathet Cardiovasc Diagn 1: 157,
1975 8 Meng CCL, Eckner FAO, Lev M: Coronary artery distribution in tetralogy of Fallot. Arch Surg 90:363, 1965 9 Berry BE, McGoon DC: Total correction for tetralogy of Fallot with anomalous coronary artery. Surgery 74:894,
1973 10 Anderson KR, McGoon DC, Lie JT: Surgical significance of the coronary arterial anatomy in truncus arteriosus communis. Am J Cardiol 41:76, 1978 II Shaher RM, Paddu GC: Coronary arterial anatomy in complete transposition of the great vessels. Am J Cardiol
17:355, 1966 12 Keeton BR, Lie JT, McGoon DC, Danielson GK, Ritter 00, Wallace RB: Anatomy of coronary arteries in univentricular hearts and its surgical implications. Am J Cardiol 43:569, 1979 13 Fortuin NJ, Roberts NC: Congenital atresia of the left main coronary artery. Am J Med 50:385, 1971 14 Vidne BA, Nili M, Aygen M, Levy MJ: Congenital atresia of the left main coronary artery ostium. Scand J Thorac Cardiovasc Surg 13:37, 1979
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15 Price AC, Lee DA, Kagan KE, Baker WP: Aortic dysplasia in infancy simulating anomalous origin of the left coronary artery. Circulation 48:434, 1973 16 Stryker WA: Coronary occlusive disease in infants and children. Am J Dis Child 77:280, 1946 17 Chernausek SD, Swan DC, Moller JH, Vlodaver Z, Edwards JE: Clinical pathologic conference. Am Heart J
91:249, 1976 18 Peterson T A, Todd DB, Edwards JE: Supravalvular aortic stenosis. J THoRAc CARDIOVASC SURG 50:734, 1965 19 Norris RF: Syphilis aortitis in childhood and youth. Report of two cases with sudden death. Johns Hopkins Med
J 57:206, 1935 20 McDonald S Jr: Syphilitic aortitis in young adults with special reference to a congenital etiology. Br J Vener Dis
10:183, 1934 21 McMahon HE, Dickinson PC: Occlusive fibroelastosis of coronary arteries in the newborn. Circulation 35:3, 1967 22 Chipman CD: Calcific stenosis of coronary arteries in infancy. Can Med Assoc J 83:955, 1960 23 Goormaghtigh N, De Vos L, Blancpuaert A: Ostial stenosis of coronary arteries in nine year old girl. Arch Intern Med 95:341,1955 24 Grant RT: Development of the cardiac coronary artery vessels in the rabbit. Heart 13:261, 1926 25 Halloran KH: The telemetered exercise electrocardiogram in congenital aortic stenosis. Pediatrics 47:31,1971 26 Chandramouli B, Ehmke DA, Lauer RM: Exerciseinduced electrocardiographic changes in children with congenital aortic stenosis. J Pediatr 87:725, 1975