Catheterization and Cardiovascular Diagnosis 5:371-384
(1979)
Anomalous Origin of the Right Coronary Artery From the Pulmonary Artery With Large Left-to-Right Shunt (Anomalous Right Coronary Artery) Gustavo A. Bermudez, MD, Roberto Abdelnur, MD, Allen I. Midell, MD, and Robert Replogle, MD A coronary arteriovenous fistula was diagnosed in a 20-year-oldwhite male because of a continuousmurmur atypically located along the left sternal border. Cardiac catheterization revealed a large left-to-right shunt, and selective coronary arteriography established the precise anatomic diagnosis. The patient was treated successfullyby surgical relmplantation of the anomalous coronary artery into the aorta and ligation of its origin at the pulmonary artery. The embryological and clinical features of this anomaly are discussed, and mechanismsfor its productionare suggested. Attention is calledto our observation of an apparent male sex predilection of this anomaly from review of the literature, in addition to the present patient. This is apparently the fourth patient with this anomaly whose condition was diagnosed antemortem by selective coronary arteriography and the fourth to have been treated by aortocoronary anastomosis providing an additive supply for boththe present and the future. This Is alsothe second case in the literature to have the transplanted right anomalous coronary artery demonstrated by selective coronary arterlography. It is likely that, with increasing use of selective coronary arteriography inthe diagnosticwork-up of cardiac patients, morecaseswill be discovered and treated surgically. Key words: coronary artery anomalies, coronary artery fistulas, coronary arteriography
INTRODUCTION Anomalous origin of the right coronary artery from the pulmonary artery is an infrequent but important anomaly. It must be considered in the differential diagFrom the Cardiovascular Division, Columbus Hospital, and the Cardiac Surgery Division, 04 partment of Surgery, The University of Chicago.
Address reprint requests to Gustavo A. Bermudez, MD, Cardiovascular Division, Columbus Hospital, 2520 N. Lakeview Avenue, Chicago, IL 60614. Received June 2, 1979; revision accepted September 10, 1979.
0098-6569/79/0504-0371$02.60 0 1979 Alan R. Liss, Inc.
372
Bermudez e t al
nosis of any continuous murmur. The abnormality could be the cause of significant sequelae such as congestive heart failure, infective endocarditis, coronary insufficiency, and even sudden death [2, 151. The advent of selective coronary arteriography has more accurately defined the anatomy of this interesting lesion and has been responsible for the more frequent recognition of this problem in recent years. Selective coronary arteriography is absolutely essential for the precise diagnosis and surgical treatment of this anomaly. CASE REPORT
The patient is a 20-year-old, well-nourished white male with no acute or chronic distress. He was referred to the Cardiovascular Division of Columbus Hospital for evaluation of breathlessness, easy fatigability, and presence of a cardiac murmur. Upon physical examination he was found to be acyanotic, had a blood pressure of 110/50 mm Hg and a pulse rate of 88/min. The peripheral arterial pulse and the jugular venous pulse were normal. The left ventricular impulse was prominent and hyperdynamic. The first heart sound was normal. The pulmonic component of the second heart sound was loud and varied normally with respiration. A grade 3/6 continuous murmur was heard along the left sternal border. The murmur was high-pitched in character and was best heard from the third or fourth intercostal space, as well as along the right sternal border. The murmur began at the first sound, peaked in systole, and persisted until late-diastole (Fig. 1). The remainder of the physical examination was within normal limits. The electrocardiogram showed left ventricular hypertrophy (Fig. 2). Chest x-ray film demonstrated a prominent left ventricular border with increased pulmonary blood flow (Fig. 3). An echocardio-
Fig. 1. Phonocardiogramtaken over the fourth left intercostal space at the sternal border and ECG demonstrating a prominent, high-frequency, continuous murmur, with the systolic component louder than the diastolic.
Anomalous Origin of the Right Coronary Artery
373
Flg. 2. Scalar electrocardiogram (A) and vector cardiogram ( 6 4 )show left ventricular hypertrophy.
374
Bermudez et al
Fig. 3. Posteroanterior (A) and left anterior oblique (6)chest x-ray films demonstrating a prominent left ventricular border with Increased pulmonary vascular markings. The prominent upper left cardiac border was probably produced by the proximal dilated left coronary artery.
Anomalous Origin of the Right Coronary Artery
375
376
Bermudez e t al TABLE I. Cardiac Catheterization Data 02
Position Superior vena cava Right atrium Right ventricle Pulmonary artery Left atrium Left ventricle Aorta
Systemic (cardiac) index (liters/min/m2) Pulmonayr blood flow (1!ters/min/rn2)
de/Qs Left-to-right shunt Left ventricular enddiastolic volume Ejection fraction
Saturation
0 2 Content
(%I
(vol %)
72.0 17.5 80.0 88.0 97.5 97.0 97.0
14.3 15.4 15.8 17.5 19.3 19.24 19.24
Pressure (mm Hg)
6 2818 27/13 (19) 12 104/13 104/60
2.8
7.5 2.7:l 4.1 82.0 0.40
Qp/Qs = pulmonary flow versus systemic flow.
gram (Fig. 4) depicted two ventricles. The interventricular septum showed abnormal type A motion. The aortic root was dilated and there was an echo-free space between two parallel linear echoes in front of the right ventricle. There was no posterior echo-free space. Cardiac catheterization revealed a large left-to-right shunt at the pulmonary artery level, giving a pulmonary/systemic flow ratio of 2.7: 1 (Table I). Elevated left ventricular end-diastolic pressure (13 mm Hg) and elevated mean left atrial pressure (12 mm Hg) were recorded. Selective coronary arteriography and aortography showed a huge, markedly dilated, tortuous left anterior descending coronary artery, which continued around into the usual position of the right coronary artery and ended in the main pulmonary artery. A cluster of irregular vessels crossed over the lower and basal portion of the right ventricle and communicated with this large vessel (Fig. 5). Attempts to catheterize the right coronary artery were unsuccessful. Furthermore, the right coronary artery could not be visualized from the aortic root injection. A diagnosis of anomalous origin of the right coronary artery communicating with the left anterior descending coronary artery was made, and surgical treatment was recommended. At operation, large, tortuous left anterior descending and circumflex coronary arteries and a myriad of smaller branches were noted throughout the entire anterior and inferior myocardium communicating with a thin-walled dilated right coronary artery that was vein-like in its appearance. It appeared to arise from the right side of the main pulmonary artery. A thrill was felt at the origin of the right coronary artery, and application of pressure at this point abolished flow throughout the entire vessel without any physiological impairment. After the right coronary artery was transected from the pulmonary artery a vigorous backflow of fully saturated blood was noted, indicating retrograde flow of a systemic arterial source. The anomalous right coronary artery was ligated at its origin, and the distal portion of the vessel was
Anomalous Originof the Right Coronary Artery
377
Fig. 5. Selective left coronary arteriogram and aortogram in the right anterior oblique projection show a huge and tortuous left coronary and left anterior descending artery (A, early frame) filling numerous collateral channels (B, late frame); right coronary artery is now visualized by contrast materialflowing retrogradefrom left coronary artery, with ultimatedrainage into the main pulmonary artery.
378
Bermudez et al
5 implanted into the aorta at the appropriate sinus of Valsalva. After completion of the procedure, the thrill disappeared. Unfortunately, we did not have a probe large enough to measure the flow through the transplanted vessel. Postoperatively, no murmur was present, and the patient made an entirely uneventful recovery. Four months after the operation, the patient was readmitted for right and left heart
Anomalous Origin of the Right Coronary Artery
379
Fig. 0. Selective coronary arteriograms in the right (A) and left (B)anterior oblique projections mveal antegradeblood flow from the aorta intothe left and the dilated transplantedright coronary arteries. The previously noted intercoronary collaterals are absent.
380
Berrnudez et al
catheterization and selective coronary arteriography. He had been asymptomatic. The eIectrocardiogram, vectocardiogram, and chest x-ray were now normal. An M-mode echocardiogram revealed absence of the anterior echo-free space, probably due to the disappearance of the large intercoronary collaterals.
Anomalous Origin of the Right Coronary Artery
381
Cardiac catheterization revealed normal pressures and oxygen saturation. Selective coronary arteriograms demonstrated antegrade blood flow into both the left and the transplanted right coronary arteries. The transplanted right coronary artery remained dilated, as was the proximal left coronary artery, but the previously shown intercoronary collaterals were not visualized (Fig. 6). DISCUSSION Anomalous right coronary artery originating from the pulmonary artery was first described by Brooks in 1866 [I]. The lesion was originally thought to be benign, but Wald [ l l ] has recently suggested that this entity can be dangerous and can be responsible for clinical symptoms. Our review of the literature has revealed 19 cases [l-151 wherein the right coronary artery arose from the pulmonary artery. Seven of these patients were diagnosed antemortem by aortography or coronary arteriography (Table 11). Most patients with this anomaly have had no other cardiac malformation. Our case is the sixth patient with an isolated anomalous right coronary artery to be diagnosed antemortem by angiography (the fourth by selective coronary arteriography) and the fourth patient to have the artery surgically implanted into the aorta. The pathogenesis of this defect relates t o the magnitude of the shunt relative t o the flow through the anomalous vessel. It has been suggested that the direction of the blood flow is dependent upon the pulmonary vascular resistance and the degree of intercoronary collateral circulation. There is evidence that the blood flow is directed preferentially from the normally originating left coronary artery, through the low resistance of the rich intercoronary collaterals, into the large anomalous right coronary artery, and finally escaping into the pulmonary artery resulting in a large left-to-right shunt [16]. This makes this lesion analogous to a coronary arteriovenous fistula. It is reasonable to assume, therefore, that this malformation could drain blood away from the myocardium, resulting in myocardial ischemia or even infarction (“coronary steal”) [ 171. Even though this is theoretically true, angina pectoris and electrocardiographic evidence of severe ischemia have not been documented and are apparently uncommon. Our patient had the largest reported shunt of all the reported cases, contributing to a volume overload of the left ventricle. Consideration of embryologic development of normal coronary arteries clarifies the proposed mechanism of this anomaly. The first indication of the coronary arteries in rabbits appears as thickening of the aortic endothelium in embryos of 10 mm length. This occurs just before division of the truncus communis into the aorta and pulmonary artery by growth of the endocardial cushions. Both arteries pass at first to the bulbus cordis and then spread out over the heart, uniting with the capillary network and intertrabecular spaces in the developing myocardium. When the endocardial cushions approach and fuse to separate the trunks, displacement of the arteries by a few cell diameters could determine whether they remain on the aortic or the pulmonary wall [18]. Factors influencing this division are as yet unknown. Hackensellner [191 suggested that each of the six semilunar valve regions in the aorta and the pulmonary trunk is potentially able to form an anlage of a coronary artery. Under normal circumstances, only the anlagen arising from the right and left semilunar valve regions of the aorta develop into coronary arteries, whereas the others situated in the remaining semilunar valve areas either do not form at all or rapidly become involuted.
F
F F M F
F
16
6%
59
42 17 12 64
25
Rowe and Young 161 Pribble [ 71
Burroughs e t a1 [ 81
Ranniger e t a1 [ 9 I
Rhantigan and de la Torre [ l o ] Wald e t al [ 141
M M M M
F
M
2.7:1
1.7:l Not done Not done
1.8:l
Not done
Yes
No
No
Yes
No
No
No No
Fatigue Crib death CHF Dyspnea
Cardiac arrest
CHF, atrial fibrillation
Left coronary artery, occluded by a thrombus, cardiac arrest
Left coronary artery plaques, HBP
Tetralogy of Fallot and PDA
Left coronary artery arteriosclerosis Left coronary artery arteriosclerosis and syphilitic aortitis, CHI: Left coronary artery arteriosclerosis, CHF, HBP Left coronary artery arteriosclerosis, HBP ASD, fatigue Angina pectoris and coronary arteriosclerosis AP window, VSD, partial malrotation of great vessels, fatigue
Left coronary artery arteriosclerosis
Other Cardiac Lesions and Symptoms
Dead
Died on the 56th postoperative day Dead
Alive
Result
Transplantation
Transplantation
Alive, well
Alive, well
Transplantation Alive Ligation plus saphenous vein graft Transplantation Alive, well
Refused
Not done
Not done
Transplan tation
Ligation
Operation
AP = aortopulmonary window; ASD = atrial septal defect; CHF = congestive heart failure; ECG = electrocardiogram; HBP = hypertension; PDA = patent ductus arteriosus; Qp/Qs = pulmonary flow vs systemic flow; VSD = ventricular septal defect.
Bermudez e t a1 [ 21 ]
Lerbergetal[13)
11 2 72 20
Yes No No Yes
M F
7 55
Cronk e t a1 [ S ]
Tingelstad e t a1 [ 15) Eugster and Oliva [ 1 1 1 Bregman e t a1 [ 121
No
M
90
Jordan e t a1 [ 4 ]
M
14
Monckeberg [2] Schley [ 31
No
not M given M 30 M 61
Brooks [ 11
-
Age
Author
Coronary Sex 6 p h s Arteriography
TABLE I I . Anomalous Right Coronary Artery From The Pulmonary Artery
1 1
Yes
1
No
1
1
1
1
1
1
Autopsy
Anomalous Origin of the Right Coronary Artery
383
According to this involution-persistence theory, anomalous origin of the right coronary artery from the pulmonary artery is due to the persistence of the coronary anlagen that have developed in the right posterior pulmonary sinus (future left coronary artery), but failure of development or rapid involution of the other anlagen. The greater incidence of anomalous left coronary artery, as compared with the right, may be explained by the proximity of the left sinus of Valsalva of the aorta to the septum of the truncus arteriousus, with the result that small displacement of its anlage would cause the left coronary artery ostium to fall within the pulmonary artery. The corresponding right sinus of Valsalva is much farther from the septum, so that a considerable displacement of the right coronary artery anlage would be required to cause the anomalous origin of this vessel from the pulmonary artery. In all cases of anomalous origin of the right coronary artery the left coronary artery has a normal origin and distribution. This situation is compatible with the metabolic requirements of the areas perfused by the right coronary artery which belong mostly to low-pressure systems (right ventricle and atrium). These chambers have a low intramural tension and therefore can be supplied by a low-pressure vessel, explaining the absence of ischemia or infarction along the course of the right coronary artery in the majority of the cases. In several of these patients [71 where the right coronary arosefrom the pulmonary artery, arteriosclerosis was present in the left coronary artery but was absent in the right. This could be influenced by the pressure difference between the two vessels, which could result in ventricular dysfunction when associated with acquired cardiovascular disease. Cardiac catheterization alone is not very useful in the differential diagnosis between anomalous right coronary artery from the pulmonary artery and a coronary artery fistula opening into the pulmonary artery because the results may be identical. Appropriate angiography will reveal a dilated and tortuous left coronary artery arising from the aorta and later filling of the pulmonary artery. An anomalous coronary artery arising from the pulmonary artery is readily confused on angiography with a single coronary artery with a fistulous communication into the outflow tract of the right ventricle. In both malformations there is generalized dilatation (“cirsoid aneurysms”) of the coronary arterial system, and only a single coronary artery arises from the aorta. Selective left coronary arteriography depicts the flow pattern from the left coronary to the right coronary artery to the pulmonary artery, and this allows a better understanding of the altered anatomy and physiology, which is essential for a conclusive diagnosis. The ideal operative procedure appears to be reimplantation of the anomalous vessel from the pulmonary artery into the aorta, thereby restoring the correct anatomy. An alternative approach that has been attempted has included ligation of the vessel with insertion of a saphenous vein coronary artery bypass 120,211. This procedure establishes dual inflow into the coronary arterial system and should overcome the disadvantage of only a left coronary artery originating from the aorta in the event that coronary artery disease develops. Although this anomaly is compatible with long life, the potential complications in untreated patients and the relative simplicity of the operation without need of cardiopulmonary bypass indicates that early correction be performed whenever the diagnosis is established [2 11. The distribution by sex of all reported cases of anomalous right coronary artery originating from the pulmonary artery, including our own (Table 11), shows a preponderance of male subjects of as much as 2 to 1. This is in contradistinction to
384
Bermudez e t al
the female preponderance of the anomalous left coronary artery from the pulmonary artery. No conclusions can be drawn however, from the very small number of cases reported. ACKNOWLEDGMENTS
We gratefully acknowledge the technical assistance of Sandy Volk and the editorial and secretarial assistance of Connie Pruitt in the preparation of this manuscript. REFERENCES I . Brooks H St J: Two cases of an abnormal coronary artery of the heart arising from the pulmonary artery with some remarks upon the effect of this anomaly producing cirsoid dilatation of the vessels. J Anat Physiol 20:26-29, 1885. 2. Monckeberg JG: Uber eine seltene Anomalie des Koronarterienabgangs. Zbl Herz Krankheiten 6:441445, 1914. 3. Schely J: Abnormer Ursprung der rechten Kranzarterie aus der Pulmonalis bei einem 61-jahringen Mann. Frankfurt Z Pathd 31:l-7, 1925. 4. Jordan RA, Dry TJ, Edwards JE: Anomalous origin of right coronary artery from the pulmonary trunk. Proc Staff Meet Mayo Clin 25:673478, 1950. 5. Cronk ES, Sinclair JG. Rigdon RH: An anomalous coronary artery arising from the pulmonary artery. Am Heart J 42:906-911, 1951. 6. Rowe GG. Young WP: Anomalous origin of the coronary arteries with special reference to surgical treatment. J Thorac Cardiovasc Surg 39777-780, 1960. 7. Pribble RH: Anatomic variations of the coronary arteries and their clinical significance. J Indiana Med Assoc 54:329-333, 1961. 8. Burroughs JT, Schmutzer KJ, Linder F, et at: Anomalous origin of the right coronary artery with aortico-pulmonary window and ventricular septa1 defect. J Cardiovasc Surg 3: 142-148, 1962. 9. Ranniger K , Thilenius OG, Cassels DE: Angiographic diagnosis of an anomalous right coronary artery arising from the pulmonary artery. Radiology 88:29-31. 1967. 10. Rhantigan RM, d e IaTorre A: Anomalous origin of the right coronary artery. Vasc Surg 5: I%, 197 I . 11. Eugster GS. Oliva PB: Anomalous origin of the right coronary artery from the pulmonary artery. Chest 63:294, 1973. 12. Bregman D, Brennan J , Singer A, Vinci J , Paredi E, Casarella WJ, Eddie RN: Anomalous origin of the right coronary artery from the pulmonary artery. J Thorac Cardiovasc Surg 72:626, 1976. 13. Lerberg DB, Ogden JA, Zuberbuhler JR, Bahnson HT: Anomalous origin of the right coronary artery from the pulmonary artery. Ann Thorac Surg 27237, 1979. 14. Wald S , Stonecipher K, Baldwin BJ, et at: Anomalous origin of the right coronary artery from the pulmonary artery. Am J Cardiol 27:677481, 1971. 15. Tingelstad JB, Lower RR, Eldredge, WJ: Anomalous origin of the right coronary artery from the main pulmonary artery. Am J Cardiol 30:670473, 1972. 16. Edwards JE; Direction of blood flow in coronary arteries arising from the pulmonary trunk. Circulation 29: 163, 1964. 17. Rowe GG: Inequalities of myocardial perfusion in coronary artery disease ("coronary steal"). Circulation 42: 193. 1970. 18. Grant RT: The comparative anatomy of the cardiac coronary vessels. Heart 13:285, 1926. 19. Hackensellner HA: Adzessorische Kranzgefassanlagen der arteria pulmonalis unter 63 menschlichen Embryonenserien 36 mm. Z Mikroscospischanat Forsch 62:153, 1956. 20. Cooley DA, Hallman GL, Bloodwell RD: Definitive surgical treatment of anomalous origin of left coronary artery from pulmonary artery indications and results. J Thorac Cardiovasc Surg 52:798. 1%6. 21. Midell Al, Bermudez GA, Replogle R: Surgical closure of left coronary artery-left ventricular fistula. J Thorac Cardiovasc Surg 74:199, 1977.
(1979)
Anomalous Origin of the Right Coronary Artery From the Pulmonary Artery With Large Left-to-Right Shunt (Anomalous Right Coronary Artery) Gustavo A. Bermudez, MD, Roberto Abdelnur, MD, Allen I. Midell, MD, and Robert Replogle, MD A coronary arteriovenous fistula was diagnosed in a 20-year-oldwhite male because of a continuousmurmur atypically located along the left sternal border. Cardiac catheterization revealed a large left-to-right shunt, and selective coronary arteriography established the precise anatomic diagnosis. The patient was treated successfullyby surgical relmplantation of the anomalous coronary artery into the aorta and ligation of its origin at the pulmonary artery. The embryological and clinical features of this anomaly are discussed, and mechanismsfor its productionare suggested. Attention is calledto our observation of an apparent male sex predilection of this anomaly from review of the literature, in addition to the present patient. This is apparently the fourth patient with this anomaly whose condition was diagnosed antemortem by selective coronary arteriography and the fourth to have been treated by aortocoronary anastomosis providing an additive supply for boththe present and the future. This Is alsothe second case in the literature to have the transplanted right anomalous coronary artery demonstrated by selective coronary arterlography. It is likely that, with increasing use of selective coronary arteriography inthe diagnosticwork-up of cardiac patients, morecaseswill be discovered and treated surgically. Key words: coronary artery anomalies, coronary artery fistulas, coronary arteriography
INTRODUCTION Anomalous origin of the right coronary artery from the pulmonary artery is an infrequent but important anomaly. It must be considered in the differential diagFrom the Cardiovascular Division, Columbus Hospital, and the Cardiac Surgery Division, 04 partment of Surgery, The University of Chicago.
Address reprint requests to Gustavo A. Bermudez, MD, Cardiovascular Division, Columbus Hospital, 2520 N. Lakeview Avenue, Chicago, IL 60614. Received June 2, 1979; revision accepted September 10, 1979.
0098-6569/79/0504-0371$02.60 0 1979 Alan R. Liss, Inc.
372
Bermudez e t al
nosis of any continuous murmur. The abnormality could be the cause of significant sequelae such as congestive heart failure, infective endocarditis, coronary insufficiency, and even sudden death [2, 151. The advent of selective coronary arteriography has more accurately defined the anatomy of this interesting lesion and has been responsible for the more frequent recognition of this problem in recent years. Selective coronary arteriography is absolutely essential for the precise diagnosis and surgical treatment of this anomaly. CASE REPORT
The patient is a 20-year-old, well-nourished white male with no acute or chronic distress. He was referred to the Cardiovascular Division of Columbus Hospital for evaluation of breathlessness, easy fatigability, and presence of a cardiac murmur. Upon physical examination he was found to be acyanotic, had a blood pressure of 110/50 mm Hg and a pulse rate of 88/min. The peripheral arterial pulse and the jugular venous pulse were normal. The left ventricular impulse was prominent and hyperdynamic. The first heart sound was normal. The pulmonic component of the second heart sound was loud and varied normally with respiration. A grade 3/6 continuous murmur was heard along the left sternal border. The murmur was high-pitched in character and was best heard from the third or fourth intercostal space, as well as along the right sternal border. The murmur began at the first sound, peaked in systole, and persisted until late-diastole (Fig. 1). The remainder of the physical examination was within normal limits. The electrocardiogram showed left ventricular hypertrophy (Fig. 2). Chest x-ray film demonstrated a prominent left ventricular border with increased pulmonary blood flow (Fig. 3). An echocardio-
Fig. 1. Phonocardiogramtaken over the fourth left intercostal space at the sternal border and ECG demonstrating a prominent, high-frequency, continuous murmur, with the systolic component louder than the diastolic.
Anomalous Origin of the Right Coronary Artery
373
Flg. 2. Scalar electrocardiogram (A) and vector cardiogram ( 6 4 )show left ventricular hypertrophy.
374
Bermudez et al
Fig. 3. Posteroanterior (A) and left anterior oblique (6)chest x-ray films demonstrating a prominent left ventricular border with Increased pulmonary vascular markings. The prominent upper left cardiac border was probably produced by the proximal dilated left coronary artery.
Anomalous Origin of the Right Coronary Artery
375
376
Bermudez e t al TABLE I. Cardiac Catheterization Data 02
Position Superior vena cava Right atrium Right ventricle Pulmonary artery Left atrium Left ventricle Aorta
Systemic (cardiac) index (liters/min/m2) Pulmonayr blood flow (1!ters/min/rn2)
de/Qs Left-to-right shunt Left ventricular enddiastolic volume Ejection fraction
Saturation
0 2 Content
(%I
(vol %)
72.0 17.5 80.0 88.0 97.5 97.0 97.0
14.3 15.4 15.8 17.5 19.3 19.24 19.24
Pressure (mm Hg)
6 2818 27/13 (19) 12 104/13 104/60
2.8
7.5 2.7:l 4.1 82.0 0.40
Qp/Qs = pulmonary flow versus systemic flow.
gram (Fig. 4) depicted two ventricles. The interventricular septum showed abnormal type A motion. The aortic root was dilated and there was an echo-free space between two parallel linear echoes in front of the right ventricle. There was no posterior echo-free space. Cardiac catheterization revealed a large left-to-right shunt at the pulmonary artery level, giving a pulmonary/systemic flow ratio of 2.7: 1 (Table I). Elevated left ventricular end-diastolic pressure (13 mm Hg) and elevated mean left atrial pressure (12 mm Hg) were recorded. Selective coronary arteriography and aortography showed a huge, markedly dilated, tortuous left anterior descending coronary artery, which continued around into the usual position of the right coronary artery and ended in the main pulmonary artery. A cluster of irregular vessels crossed over the lower and basal portion of the right ventricle and communicated with this large vessel (Fig. 5). Attempts to catheterize the right coronary artery were unsuccessful. Furthermore, the right coronary artery could not be visualized from the aortic root injection. A diagnosis of anomalous origin of the right coronary artery communicating with the left anterior descending coronary artery was made, and surgical treatment was recommended. At operation, large, tortuous left anterior descending and circumflex coronary arteries and a myriad of smaller branches were noted throughout the entire anterior and inferior myocardium communicating with a thin-walled dilated right coronary artery that was vein-like in its appearance. It appeared to arise from the right side of the main pulmonary artery. A thrill was felt at the origin of the right coronary artery, and application of pressure at this point abolished flow throughout the entire vessel without any physiological impairment. After the right coronary artery was transected from the pulmonary artery a vigorous backflow of fully saturated blood was noted, indicating retrograde flow of a systemic arterial source. The anomalous right coronary artery was ligated at its origin, and the distal portion of the vessel was
Anomalous Originof the Right Coronary Artery
377
Fig. 5. Selective left coronary arteriogram and aortogram in the right anterior oblique projection show a huge and tortuous left coronary and left anterior descending artery (A, early frame) filling numerous collateral channels (B, late frame); right coronary artery is now visualized by contrast materialflowing retrogradefrom left coronary artery, with ultimatedrainage into the main pulmonary artery.
378
Bermudez et al
5 implanted into the aorta at the appropriate sinus of Valsalva. After completion of the procedure, the thrill disappeared. Unfortunately, we did not have a probe large enough to measure the flow through the transplanted vessel. Postoperatively, no murmur was present, and the patient made an entirely uneventful recovery. Four months after the operation, the patient was readmitted for right and left heart
Anomalous Origin of the Right Coronary Artery
379
Fig. 0. Selective coronary arteriograms in the right (A) and left (B)anterior oblique projections mveal antegradeblood flow from the aorta intothe left and the dilated transplantedright coronary arteries. The previously noted intercoronary collaterals are absent.
380
Berrnudez et al
catheterization and selective coronary arteriography. He had been asymptomatic. The eIectrocardiogram, vectocardiogram, and chest x-ray were now normal. An M-mode echocardiogram revealed absence of the anterior echo-free space, probably due to the disappearance of the large intercoronary collaterals.
Anomalous Origin of the Right Coronary Artery
381
Cardiac catheterization revealed normal pressures and oxygen saturation. Selective coronary arteriograms demonstrated antegrade blood flow into both the left and the transplanted right coronary arteries. The transplanted right coronary artery remained dilated, as was the proximal left coronary artery, but the previously shown intercoronary collaterals were not visualized (Fig. 6). DISCUSSION Anomalous right coronary artery originating from the pulmonary artery was first described by Brooks in 1866 [I]. The lesion was originally thought to be benign, but Wald [ l l ] has recently suggested that this entity can be dangerous and can be responsible for clinical symptoms. Our review of the literature has revealed 19 cases [l-151 wherein the right coronary artery arose from the pulmonary artery. Seven of these patients were diagnosed antemortem by aortography or coronary arteriography (Table 11). Most patients with this anomaly have had no other cardiac malformation. Our case is the sixth patient with an isolated anomalous right coronary artery to be diagnosed antemortem by angiography (the fourth by selective coronary arteriography) and the fourth patient to have the artery surgically implanted into the aorta. The pathogenesis of this defect relates t o the magnitude of the shunt relative t o the flow through the anomalous vessel. It has been suggested that the direction of the blood flow is dependent upon the pulmonary vascular resistance and the degree of intercoronary collateral circulation. There is evidence that the blood flow is directed preferentially from the normally originating left coronary artery, through the low resistance of the rich intercoronary collaterals, into the large anomalous right coronary artery, and finally escaping into the pulmonary artery resulting in a large left-to-right shunt [16]. This makes this lesion analogous to a coronary arteriovenous fistula. It is reasonable to assume, therefore, that this malformation could drain blood away from the myocardium, resulting in myocardial ischemia or even infarction (“coronary steal”) [ 171. Even though this is theoretically true, angina pectoris and electrocardiographic evidence of severe ischemia have not been documented and are apparently uncommon. Our patient had the largest reported shunt of all the reported cases, contributing to a volume overload of the left ventricle. Consideration of embryologic development of normal coronary arteries clarifies the proposed mechanism of this anomaly. The first indication of the coronary arteries in rabbits appears as thickening of the aortic endothelium in embryos of 10 mm length. This occurs just before division of the truncus communis into the aorta and pulmonary artery by growth of the endocardial cushions. Both arteries pass at first to the bulbus cordis and then spread out over the heart, uniting with the capillary network and intertrabecular spaces in the developing myocardium. When the endocardial cushions approach and fuse to separate the trunks, displacement of the arteries by a few cell diameters could determine whether they remain on the aortic or the pulmonary wall [18]. Factors influencing this division are as yet unknown. Hackensellner [191 suggested that each of the six semilunar valve regions in the aorta and the pulmonary trunk is potentially able to form an anlage of a coronary artery. Under normal circumstances, only the anlagen arising from the right and left semilunar valve regions of the aorta develop into coronary arteries, whereas the others situated in the remaining semilunar valve areas either do not form at all or rapidly become involuted.
F
F F M F
F
16
6%
59
42 17 12 64
25
Rowe and Young 161 Pribble [ 71
Burroughs e t a1 [ 81
Ranniger e t a1 [ 9 I
Rhantigan and de la Torre [ l o ] Wald e t al [ 141
M M M M
F
M
2.7:1
1.7:l Not done Not done
1.8:l
Not done
Yes
No
No
Yes
No
No
No No
Fatigue Crib death CHF Dyspnea
Cardiac arrest
CHF, atrial fibrillation
Left coronary artery, occluded by a thrombus, cardiac arrest
Left coronary artery plaques, HBP
Tetralogy of Fallot and PDA
Left coronary artery arteriosclerosis Left coronary artery arteriosclerosis and syphilitic aortitis, CHI: Left coronary artery arteriosclerosis, CHF, HBP Left coronary artery arteriosclerosis, HBP ASD, fatigue Angina pectoris and coronary arteriosclerosis AP window, VSD, partial malrotation of great vessels, fatigue
Left coronary artery arteriosclerosis
Other Cardiac Lesions and Symptoms
Dead
Died on the 56th postoperative day Dead
Alive
Result
Transplantation
Transplantation
Alive, well
Alive, well
Transplantation Alive Ligation plus saphenous vein graft Transplantation Alive, well
Refused
Not done
Not done
Transplan tation
Ligation
Operation
AP = aortopulmonary window; ASD = atrial septal defect; CHF = congestive heart failure; ECG = electrocardiogram; HBP = hypertension; PDA = patent ductus arteriosus; Qp/Qs = pulmonary flow vs systemic flow; VSD = ventricular septal defect.
Bermudez e t a1 [ 21 ]
Lerbergetal[13)
11 2 72 20
Yes No No Yes
M F
7 55
Cronk e t a1 [ S ]
Tingelstad e t a1 [ 15) Eugster and Oliva [ 1 1 1 Bregman e t a1 [ 121
No
M
90
Jordan e t a1 [ 4 ]
M
14
Monckeberg [2] Schley [ 31
No
not M given M 30 M 61
Brooks [ 11
-
Age
Author
Coronary Sex 6 p h s Arteriography
TABLE I I . Anomalous Right Coronary Artery From The Pulmonary Artery
1 1
Yes
1
No
1
1
1
1
1
1
Autopsy
Anomalous Origin of the Right Coronary Artery
383
According to this involution-persistence theory, anomalous origin of the right coronary artery from the pulmonary artery is due to the persistence of the coronary anlagen that have developed in the right posterior pulmonary sinus (future left coronary artery), but failure of development or rapid involution of the other anlagen. The greater incidence of anomalous left coronary artery, as compared with the right, may be explained by the proximity of the left sinus of Valsalva of the aorta to the septum of the truncus arteriousus, with the result that small displacement of its anlage would cause the left coronary artery ostium to fall within the pulmonary artery. The corresponding right sinus of Valsalva is much farther from the septum, so that a considerable displacement of the right coronary artery anlage would be required to cause the anomalous origin of this vessel from the pulmonary artery. In all cases of anomalous origin of the right coronary artery the left coronary artery has a normal origin and distribution. This situation is compatible with the metabolic requirements of the areas perfused by the right coronary artery which belong mostly to low-pressure systems (right ventricle and atrium). These chambers have a low intramural tension and therefore can be supplied by a low-pressure vessel, explaining the absence of ischemia or infarction along the course of the right coronary artery in the majority of the cases. In several of these patients [71 where the right coronary arosefrom the pulmonary artery, arteriosclerosis was present in the left coronary artery but was absent in the right. This could be influenced by the pressure difference between the two vessels, which could result in ventricular dysfunction when associated with acquired cardiovascular disease. Cardiac catheterization alone is not very useful in the differential diagnosis between anomalous right coronary artery from the pulmonary artery and a coronary artery fistula opening into the pulmonary artery because the results may be identical. Appropriate angiography will reveal a dilated and tortuous left coronary artery arising from the aorta and later filling of the pulmonary artery. An anomalous coronary artery arising from the pulmonary artery is readily confused on angiography with a single coronary artery with a fistulous communication into the outflow tract of the right ventricle. In both malformations there is generalized dilatation (“cirsoid aneurysms”) of the coronary arterial system, and only a single coronary artery arises from the aorta. Selective left coronary arteriography depicts the flow pattern from the left coronary to the right coronary artery to the pulmonary artery, and this allows a better understanding of the altered anatomy and physiology, which is essential for a conclusive diagnosis. The ideal operative procedure appears to be reimplantation of the anomalous vessel from the pulmonary artery into the aorta, thereby restoring the correct anatomy. An alternative approach that has been attempted has included ligation of the vessel with insertion of a saphenous vein coronary artery bypass 120,211. This procedure establishes dual inflow into the coronary arterial system and should overcome the disadvantage of only a left coronary artery originating from the aorta in the event that coronary artery disease develops. Although this anomaly is compatible with long life, the potential complications in untreated patients and the relative simplicity of the operation without need of cardiopulmonary bypass indicates that early correction be performed whenever the diagnosis is established [2 11. The distribution by sex of all reported cases of anomalous right coronary artery originating from the pulmonary artery, including our own (Table 11), shows a preponderance of male subjects of as much as 2 to 1. This is in contradistinction to
384
Bermudez e t al
the female preponderance of the anomalous left coronary artery from the pulmonary artery. No conclusions can be drawn however, from the very small number of cases reported. ACKNOWLEDGMENTS
We gratefully acknowledge the technical assistance of Sandy Volk and the editorial and secretarial assistance of Connie Pruitt in the preparation of this manuscript. REFERENCES I . Brooks H St J: Two cases of an abnormal coronary artery of the heart arising from the pulmonary artery with some remarks upon the effect of this anomaly producing cirsoid dilatation of the vessels. J Anat Physiol 20:26-29, 1885. 2. Monckeberg JG: Uber eine seltene Anomalie des Koronarterienabgangs. Zbl Herz Krankheiten 6:441445, 1914. 3. Schely J: Abnormer Ursprung der rechten Kranzarterie aus der Pulmonalis bei einem 61-jahringen Mann. Frankfurt Z Pathd 31:l-7, 1925. 4. Jordan RA, Dry TJ, Edwards JE: Anomalous origin of right coronary artery from the pulmonary trunk. Proc Staff Meet Mayo Clin 25:673478, 1950. 5. Cronk ES, Sinclair JG. Rigdon RH: An anomalous coronary artery arising from the pulmonary artery. Am Heart J 42:906-911, 1951. 6. Rowe GG. Young WP: Anomalous origin of the coronary arteries with special reference to surgical treatment. J Thorac Cardiovasc Surg 39777-780, 1960. 7. Pribble RH: Anatomic variations of the coronary arteries and their clinical significance. J Indiana Med Assoc 54:329-333, 1961. 8. Burroughs JT, Schmutzer KJ, Linder F, et at: Anomalous origin of the right coronary artery with aortico-pulmonary window and ventricular septa1 defect. J Cardiovasc Surg 3: 142-148, 1962. 9. Ranniger K , Thilenius OG, Cassels DE: Angiographic diagnosis of an anomalous right coronary artery arising from the pulmonary artery. Radiology 88:29-31. 1967. 10. Rhantigan RM, d e IaTorre A: Anomalous origin of the right coronary artery. Vasc Surg 5: I%, 197 I . 11. Eugster GS. Oliva PB: Anomalous origin of the right coronary artery from the pulmonary artery. Chest 63:294, 1973. 12. Bregman D, Brennan J , Singer A, Vinci J , Paredi E, Casarella WJ, Eddie RN: Anomalous origin of the right coronary artery from the pulmonary artery. J Thorac Cardiovasc Surg 72:626, 1976. 13. Lerberg DB, Ogden JA, Zuberbuhler JR, Bahnson HT: Anomalous origin of the right coronary artery from the pulmonary artery. Ann Thorac Surg 27237, 1979. 14. Wald S , Stonecipher K, Baldwin BJ, et at: Anomalous origin of the right coronary artery from the pulmonary artery. Am J Cardiol 27:677481, 1971. 15. Tingelstad JB, Lower RR, Eldredge, WJ: Anomalous origin of the right coronary artery from the main pulmonary artery. Am J Cardiol 30:670473, 1972. 16. Edwards JE; Direction of blood flow in coronary arteries arising from the pulmonary trunk. Circulation 29: 163, 1964. 17. Rowe GG: Inequalities of myocardial perfusion in coronary artery disease ("coronary steal"). Circulation 42: 193. 1970. 18. Grant RT: The comparative anatomy of the cardiac coronary vessels. Heart 13:285, 1926. 19. Hackensellner HA: Adzessorische Kranzgefassanlagen der arteria pulmonalis unter 63 menschlichen Embryonenserien 36 mm. Z Mikroscospischanat Forsch 62:153, 1956. 20. Cooley DA, Hallman GL, Bloodwell RD: Definitive surgical treatment of anomalous origin of left coronary artery from pulmonary artery indications and results. J Thorac Cardiovasc Surg 52:798. 1%6. 21. Midell Al, Bermudez GA, Replogle R: Surgical closure of left coronary artery-left ventricular fistula. J Thorac Cardiovasc Surg 74:199, 1977.
