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Anomalous origin of the left coronary artery from the pulmonary trunk
J
THORAC CARDIOVASC SURG
1989;98:16-24
Anomalous origin of the left coronary artery from the pulmonary trunk Anatomic findings in relation to pathophysiology and surgical repair Anomalous origin of the left coronary artery from the pulmonary trunk, though a discrete anatomic malfonnation, manifests a spectrum of clinical and pathologic consequences, The objectives of this study were to characterize the primary anatomic findings in a group of specimens with anomalous left coronary artery and the extent of secondary morphologic and pathologic changes. Although the cases studied probably represent the least favorable end of the spectrum, the observed pathogenesis and evolution of secondary changes suggest that reconstruction of a two-coronary arterial system supplied through two coronary arteries would be advantageous to most patients. A high origin of the right coronary artery or location of the left coronary artery adjacent to a pulmonary cusp or branch may complicate the tunnel-type repair. In these cases, transfer of the left coronary artery to the aorta may be preferable.
Audrey Smith, FIMLS, MPhil, PhD; Robert Arnold MB, ChB, FRCP, FRCPE; Robert H. Anderson, BSc, MD, FRCPath,b James L. Wilkinson, MB, ChB, FRCP; Shakeel A. Qureshi, MB, ChB, MRCP; Leon M. Gerlis, MB, BS, FRCPath,b and Roxane McKay, BA, MD, FRCS; Liverpool and London, England
Anomalous origin of the left coronary artery from the pulmonary trunk can be considered as an anatomicclinical spectrum with two extremes, the "infantile" and the "adult." In the adult type, the collateral circulation between the right and left coronary systems is sufficiently well formed to provide a shunt from the right coronary artery via the anomalous left coronary artery to the pulmonary trunk.' In the infantile type, the collateral circulation is either poorly developed or of unfavorable distribution. In consequence, the patients have angina-like episodes and left ventricular failure
From the Institute of Child Health, University of Liverpool, Royal Liverpool Children's Hospital Alder Hey, Liverpool, England,' and the Department of Paediatric Cardiac Morphology, Cardiathoracic Institute, Brompton Hospital, London, England." Professor R. H. Anderson and Dr. L. M. Gerlis are supported by the British Heart Foundation. Dr. Audrey Smith was supported by the National Heart Research Fund at the commencement of this work but is currently supported by the Endowment Fund of the Royal Liverpool Children's Hospitals. Received for publication April 5, 1988. Accepted for publication Nov. 30, 1988. Address for reprints: Audrey Smith, PhD, Institute of Child Health, University of Liverpool, Royal Liverpool Children's Hospital Alder Hey, Eaton Road, Liverpool, Ll2 2AP, England.
16
because of myocardial ischemia. Although the syndrome is associated eponymously with Bland, White, and Garland,' the first case was recognized clinically in
1885.3 The physiologic manifestations evolve through several stages, reflecting the prevailing hemodynamic environments in the systemic and pulmonary circulations. In the fetus, the left coronary artery fills antegradely from the pulmonary trunk in which the pressure is equal to that in the aorta. After birth, myocardial perfusion depends on the extent of the collateral circulation and the rate of decline of the pulmonary arterial resistance. Row in the left coronary artery is usually reversed. Myocardial damage then follows as a result of the low pressure of coronary arterial perfusion. If the patient survives, further collateral arteries develop in response to myocardial hypoxia, which sets the scene for evolution of a "coronary arterial steal" syndrome.' In this situation the fistulous flow into the pulmonary trunk may become so large that the anastomoses lose their nutritive function and cause further myocardial damage. The physiologic consequences of poor coronary arterial perfusion and myocardial ischemia show a wide range of individual variation and have been well assessed and investigated clinically."? In contrast, the gross anatomic and histopathologic features that reflect the extent of myocardial
Volume 98 Number 1
Anomalous origin of left coronary artery
July 1989
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damage and length of survival have rarely been studied. With this in mind, we have inspected examples of this lesion in our autopsy collection, aiming also to define those anatomic characteristics of the lesion that could be of surgical significance. Materials and methods We studied 14 hearts with anomalous origin of the left coronary artery from the pulmonary trunk. The age range of the patients from whom the hearts were retrieved was from II weeks to 14 years. Two had undergone surgical treatment. Measurements taken with vernier calipers were recorded with other data on standard forms. These data were compared with the normal values given by De la Cruz and associates.' The aortic sinuses were designated as right hand (or No. I). left hand (or No.2), and nonfacing, according to the view obtained from the nonfacing aortic sinus looking toward the pulmonary trunk' (Fig. I). The sinuses of the pulmonary valve were designated right hand (or No. I) and left hand (or No.2) in similar fashion as viewed from the nonfacing sinus of the pulmonary trunk toward the aorta. Thus the left-hand aortic sinus faces the right-hand pulmonary sinus and vice versa. The size and exact location of the orifices of both right and left coronary arteries were noted in relation to the bar between the sinusal and truncal components of the great arteries and to the commissures of the arterial valves (Fig. 2, a and b). A pin was inserted from the aorta through the center of the empty left-hand sinus (No.2) just above the aortic bar. The distance was then measured between the emergence of the pin on the outside of the aorta and the posterior aspect of the anomalous left coronary artery. The length of the main stem of the left coronary artery was also measured (Fig. 3). The morphology' of each coronary arterial orifice was examined and compared with that of a series of 10 hearts from otherwise normal neonates and infants who had died of noncardiac causes. The angle subtended by each proximal coronary artery to the long axis of its arterial trunk was approximated and compared with the same data from the normal hearts. The distribution and caliber of the main coronary arteries and branches were recorded. Coronary arteries were deemed to be hypoplastic either if there was a uniformly long segment with a narrow lumen" or if they appeared to be disproportionately small for the size of the ventricle by comparison with normal arteries. They were not considered to be dilated unless conspicuously larger than normal. Blocks of myocardium for histologic examination were removed from the anterolateral wall of the right ventricles and the anterior and posterior walls and apexes of the left ventricles of all the specimens. Blocks for microscopic study were also removed from the right and left coronary arteries of three selected specimens. Sections were stained by Mayer's hematoxylin and eosin stain and by Weigert's elastin stain with van Giesen's counterstain. The changes in the tissue were described as slight (+). moderate (++). or severe (+++) according to the semiquantitative scheme applied by Sekiguchi, Hiroe, and Morimoto" and Yonesaka and Becker."
Findings All the hearts had usual (solitus) atrial arrangement with concordant atrioventricular and ventriculoarterial connections. A moderately large perimembranous ventricular septal defect with malalignment of the outlet
A
AD
Fig. 1. The aortic and pulmonary valves from above in their normal spatial relationship, that is, right posterior to left anterior. The enumeration of the aortic and pulmonary valve sinuses in relation to the nonfacing sinuses is indicated. Sinus I is to the right hand and sinus 2 is to the left hand when viewing the opposite great artery from the non facing sinus. A. Anterior: Ao. aorta: AD. anterior descending (interventricular) artery; C. circumflex artery; L. left; LMCA. main stem of the left coronary artery: NF. non facing sinus; P, posterior; PT, pulmonary trunk; R. right; RCA. right coronary artery.
septum was present in one heart, together with a defect of the oval fossa. The oval fossa was patent in two hearts and was fenestrated in one. The atrial septum was intact in the remaining hearts. The arterial duct was probe patent in two cases. Coarctation of the aorta existed in one specimen. In another heart the pulmonary valve had two leaflets. The size of both the aortic and pulmonary valves was normal throughout the series. The anomalous left coronary artery originated in association with the right-hand facing pulmonary sinus (I) in all the specimens. The commissures between the facing aortic and pulmonary sinuses opposed each other directly in each of the hearts (including the specimen in which the pulmonary valve had two leaflets). Morphology of the sinuses of the arterial valves, the coronary arterial orifices, and the proximal coronary arteries. The right coronary arterial orifice was always funnel-shaped in the normal hearts, with the larger circular end of the funnel opening from the aortic lumen. The narrow end determined the luminal diameter of the proximal right coronary artery. The angle subtended to the aortic root was approximately 90 degrees. The main stem of the left coronary artery originated with parallel walls from its aortic orifice, which was always elliptic in the normal heart. The luminal diameter stayed constant until the bifurcation. This artery always subtended an acute angle to the main axis of the aortic root in the normal group. The
The Journal of
18
Thoracic and Cardiovascular
Smith et al.
Surgery
a ABNORMAL
NORMAL
CD
CD 0@ ,,
\NF AORTIC VALVE
2)
5
CDCD/ r\NF 1
~cl'
R+L P
AORTIC VALVE
A
b
ABNORMAL
NORMAl.
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-i~'\U
NF,'
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2
AORTIC VALVE
,
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PULMONARY VALVE
Fig. 2. a, Right coronary artery origin (circles) in relation to right-hand aortic facing sinus (No. I) in the normal series and to both aortic sinuses (No.1 and No.2) in the abnormal series. Numbers inside the circles indicate the incidence in each location. In the abnormal group there are two hearts in which the right coronary artery takes a high origin. one of these being above the left-hand aortic facing sinus (No.2). b, Left coronary artery origin (circles) in the normal and the abnormal series. In the normal series the left coronary artery always takes origin in relation to the left-hand aortic facing sinus (No. 2), whereas in the abnormal series it takes origin in relation to the right-hand pulmonary facing sinus (No. 1). In three of these hearts, the origin was high above the bar between the sinus and truncal portion of the pulmonary trunk. The orifice impinged on a commissure in five specimens. NF. Nonfacing sinus.
combination of angulation in both vertical and horizontal planes produced a spur in the margins of its orifice. Descriptions of such anatomic characteristics in normal hearts have been recorded by McAlpine." The funnel shape was observed in only seven of the right coronary arterial orifices in the abnormal heart series (50%). The lumen in the remainder was either the same size as that of the orifice (six hearts 43%) or else larger (one heart, 7%). The right coronary artery in 11 abnormal hearts connected at a normal angle with the aortic root, but in another two abnormal hearts its origin was high above the sinotruncal bar (2 mm and 8 mm,
Fig. 3. The distance (Y) that was measured between the midpoint of the empty aortic sinus (No.2) and the posterior aspect of the main stem of the left coronary artery from its anomalous origin in pulmonary sinus NO.1. The length of main stem of the left coronary artery before its branching is also indicated (Z). A. Anterior; AD. anterior descending (interventricular) artery; Ao. aortic valve; C. circumflex artery; L. left; LMCA. main left coronary artery; NF. nonfacing sinus; P. posterior; PT. pulmonary trunk; R. right; RCA. right coronary artery.
respectively). The first of these was stenotic (Fig. 4). Both had a spur in the margin, which was reminiscent of the normal arrangement of the orifice of the left coronary artery. The proximal portion of the right coronary artery ran between the aortic and pulmonary roots in the second specimen. The right coronary artery was grossly convoluted in the remaining heart, its proximal portion being directed cranially for 10 mm (Fig. 5). In the normal hearts, neither coronary arterial orifice impinged on a commissure (Fig. 2). In contrast, although the orifices of the right coronary arteries were always clear of the commissures of the aortic valve (Fig. 2, a), in five abnormal hearts the origin of the anomalous left coronary artery was either very close to or directly impinged on a commissure of the pulmonary valve (Fig. 2, b. and Fig. 6). In a further three hearts, the orifice of the aberrant left coronary artery was displaced 3 or 4 mm above the sinopulmonary bar (Fig. 2, b). The left cor.' rary arterial orifice impinged on the origin of the right pulmonary artery in one of these (Fig. 7). The characteristic spur seen at the margins of the orifice of the normal left coronary artery was absent from the aberrant left coronary artery in four hearts from the group that were not treated surgically. These orifices were circular rather than elliptic.
Volume 98 Number 1
Anomalous origin of left coronary artery
July 1989
19
, 1!'"
RA RV Fig. 4. Right superior oblique view of a stenosed orifice of the right coronary artery (arrow). The aortic trunk has been opened into the orifice to enlarge it. Ao, Aorta; i, infundibular branch: RA. right atrium; rc, right coronary artery; RV, right ventricle. The comparable size of coronary arterial orifices is indicated in Table I. The angle subtended by the main stem of the left coronary artery relative to the pulmonary trunk was less constant in the abnormal hearts than that of the main stem to the aorta (Table II). The distance between the midpoint of the empty left-hand aortic sinus (No.2) and the posterior aspect of the aberrant left coronary artery varied from 2 to 18 mm (Fig, 3), The length of artery before its branch point (in other words, that length which would have been available for surgical mobilization) ranged from 2 to 12 mm (the comparable value in the normal series was from 1 to 5 mm). These measurements were not related to age, nor was the length of artery available for mobilization related to the distance between its origin from the pulmonary artery and the empty aortic sinus (Fig. 3). In 12 of the abnormal hearts, the right coronary artery gave rise to the posterior interventricular artery. As described earlier, this artery and its branches were conspicuously dilated and convoluted in the oldest patient (Fig. 5). The artery of the second oldest patient was similarly but less markedly convoluted. In another four hearts from younger patients, the right coronary artery and some or all of its branches were dilated but showed lesser degrees of convolution.
Fig. 5. The dashed line indicates the tortuous course of the dilated right coronary artery. Ao. Aorta; RA. right atrium; RV, right ventricle.
Fig. 6. The anomalousoriginof the left main coronary artery below the sinopulmonary bar, impinging on the commissure between pulmonary sinuses 1 and 2 (arrow). PT, Pulmonary trunk; R V, right ventricle.
Despite the abnormal connection of the left coronary artery, its subsequent course and branching pattern were normal. The caliber and length, however, were extremely variable. The left coronary artery extended to supply a poorly developed posterior interventricular branch in two hearts. The right coronary artery was also hypoplastic in
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The Journal of Thoracic and Cardiovascular Surgery
Smith et al.
Fig. 7. The anomalous origin of the left main coronary artery (arrow) is seen at the branch point of the right pulmonary
artery. L, Left pulmonary artery; PT. pulmonary trunk; R. right pulmonary artery; RV. right ventricle.
Table I. Size of right coronary arterial orifices compared with left* No. of specimens Comparable size Right> left Right < left
Normal series
Abnormal series
10 10
12 7
2
Fig. 8. Arrows indicate a collateral artery. It runs anteriorly to the pulmonary root from the right coronary artery, under the main left coronary artery, and connects with the left coronary artery at the branching point of the circumflex artery. Ao. Aorta; C circumflex artery; LC left coronary artery; PT, pulmonary trunk; RC right coronary artery.
3
"Two postoperative specimens were not comparable.
these two specimens. In a further four hearts, the caliber of the arterial supply to the entirety of the left ventricle was poor, all the arteries being hypoplastic. In three hearts the distal portions of the circumflex and anterior interventricular branches were narrow, although the proximal segments were of good caliber. The left coronary artery and its branches were of normal dimensions in only five specimens (36%). Collateral arteries. No collateral arteries were visible grossly in 12 of the specimens (85.8%), although a tenuous communication was observed between the anterior interventricular artery and the infundibular or right marginal branches of the right coronary artery in six of these (42.8%). Obvious collateral arteries were seen in only two cases (14.2%). In one of these, a well-developed anomalous proximal branch from the right coronary artery coursed across the subpulmonary infundibulum and anastomosed with the proximal part of the circumflex artery (Fig. 8). Another specimen showed a similar collateral artery coursing across the pulmonary root, anastomosing in this case with the anterior interventricular descending artery.
Table II. Angle of proximal main left coronary artery to main axis of aorta or pulmonary trunk* Number of specimens Acute anteroapical inclination to long axis of aorta or pulmonary trunk Laterally oriented left main coronary artery Posteriorly oriented left main coronary artery
Normal
Abnormal
10
12 8
9
3
*Two postoperative specimens were not comparable.
The artery to the sinus node. The artery to the sinus node originated from the aberrant left coronary artery in three specimens. In all except one of the remaining cases it arose from the right coronary artery. It could not be demonstrated by blunt dissection in the last heart. Pathologic condition of the left ventricle. A spectrum of gross pathologic change was apparent throughout the series, being most obvious in the left ventricle. This chamber was dilated in all hearts from infants with an intact interventricular septum. In those that could be assessed against age (nine hearts), the ventricular inlet
Volume 98 Number 1 July 1989
Anomalous origin of left coronary artery
2I
Fig. 9. a, The dilated, thin-walled left venticle of a heart with anomalous origin of the left coronary artery from the pulmonary trunk. The mitral valve is small and both anterolateral and posteromedial papillary muscles are hypoplastic. The root of the posteromedial papillary muscle (large open arrow) is seen to be well above the apex of the ventricle. The corda I attachments are unduly long (black arrow). Interstitial fibrosis is present at the root of the anterolateral papillary muscle (curved open arrow). b, The left ventricle of a normal heart for comparison with a, showing the root of the posteromedial papillary muscle (arrow) to be close to the apex of the ventricle. A. Apex; AL. anterolateral papillary muscle; Ao. aorta; MV. mitral valve; PM. posteromedial papillary muscle.
and outlet dimensions were greater than published normal mean values" (p < 0.001). Generalized thinning of the left ventricular apex was observed in four specimens, and localized thinning (aneurysmal) was found in two others, being duplicated in one. The left ventricular wall was hypertrophied in two hearts, one with dilatation of the cavity and the other without. The circumference of the mitral valve could be assessed against age in I I hearts. It was below the minimum end of the normal range" in two specimens, within the normal range in five, and larger in the remaining four hearts. The overall differences were not significant when compared with normal values. On the other hand, both anterolateral and posteromedial papillary muscles were small for the size of the left ventricle in 12 specimens (85.8%, Fig. 9, a and b). The characteristics of these muscles ranged from short to hypoplastic, with ventricular attachments well above the apex (Fig. 9, a). They were frankly atrophic in two hearts. The tendinous cords were unduly long in four of the specimens with average or small mitral valves, and the leaflet material was thickened and dysplastic in one case, again with a small valve. Macroscopic evidence of endocardial thickening and
subendocardial sclerosis was seen in seven different specimens. Gross infarction was observed in two hearts but extended only into the inner third of the myocardium. Histology. Histologic features indicating chronic myocardial ischemia included endocardial thickening, interstitial fibrosis, and calcification (Table III). Recent acute ischemia was shown by myocytic degeneration and fragmentation, sometimes accompanied by cellular infiltration. No abnormalities were observed in any of the blocks taken from the right ventricle, but ischemic changes were present in the blocks from the left ventricle of all specimens with anomalous origin of the left coronary artery. These changes ranged from mild to severe. They varied from case to case and from one myocardial region to another. The overall degree of severity showed no relationship to the age of death. Endocardial thickening, with noted increase in fibrous and elastic tissue, was observed in hearts from all but the oldest patients. In no case was it regarded as severe and, in this series, it never resembled endocardial fibroelastosis. The endocardial thickening was slightly more marked in the apex than in the anterior wall. The posterior wall was least affected. The changes tended to
22
The Journal of Thoracic and Cardiovascular Surgery
Smith et al.
Table
m Interstitial Fibrosis
Endocardial thickening Age II wk
3 rna 3 rna 6 rna 8 rna 9 rna I yr 7 rna 2 yr 4 yr 9 rna 5 yr 14 yr
P
A
0
++ + ++ + + + ++ ++ +
0
+ ++ + +
Apex
+ + + ++
+ ++ ++ ++ ++ + + ++ +
0 0
0 0
0
Myocyte fragmentation
Penetration offibrosis
Apex
A
P
Apex
A
P
Apex
A
P
+ + ++ ++ ++ + +++ ++ +++ ++ ++
+ + ++ + ++ +++ ++ + ++
+++ + ++ + + ++ ++ + +
+ + ++ + ++ +++ + + ++
+++ + ++ + + ++ ++ + +
+ + + + ++ + + + +
0
0
0 0
+ + + + + + ++ + + ++ +
++ + ++ + ++ + + + +
0
+ + ++ +++ ++ + ++ ++ +++ ++ +++
0
0 0
++
+
++
+
Calcification A
P
Apex
+ + + +
+ +
+
A, Anterior wall; P, posterior wall
be rather more marked in hearts from children under I year of age, but this difference was not statistically significant. Interstitial fibrosis was always maximal toward the endocardial aspect of the ventricular wall. It tended to be most marked in the anterior wall and least marked at the apex. It did not appear to be age related. No instances of acute infarction were noted in the tissue blocks taken from the specified standard. sites. The milder changes observed appeared with equal frequency in different regions of the left ventricle and were not age related. Small areas of dystrophic calcification were present in six cases. These were found apically in two cases, in the anterior wall in three, and in both regions in the remaining heart. These changes were not related to age.
Discussion Left ventricular damage resulting from myocardial ischemia in patients with anomalous origin of the left coronary artery from the pulmonary trunk is associated with a range of pathologic findings. These include endocardial and subendocardial fibrosis, damage to the papillary muscles, patchy myocardial necrosis, and dilatation and formation of aneurysms. Mitral incompetence frequently developsl4,15 and may be associated with leaflet dysplasia, presumably of secondary origin. The extent and severity of these changes is variable and correlates poorly with the age of the patients at death. Development of collateral arterial supply is a vital factor in determining the degree of myocardial ischemia and its consequences. Nonetheless, a number of other anatomic variables may contribute to the evolution of the clinical picture, the severity of ventricular dysfunction,
the extent of myocardial damage, and the outcome of attempts to correct the malformation surgically. It is hard to quantify the influence of the numerous anatomic variations described in this study. These would be catalogued as both major and minor according to the approach suggested by Ogden." The very presence of so many abnormalities, even if "minor" in some cases, attests to this malformation not being a single, simple anatomic malformation of the left coronary artery. As indicated by Becker," it also points to the potential dangers in the simplistic division of coronary arterial malformation into major and minor features. Be that as it may, what is the significance of the additional variables? Minor variations associated with the anomalous left coronary artery included high take-off (Fig. 2, a and b). In the past, when banding of the pulmonary trunk was considered a surgical option, this combination has proved fatal." High take-off of a coronary artery may also affect blood flow. 19 This has been considered important in the etiology of ischemic heart disease. It is likely to be even more significant when perfusion is already compromised by origin of the left coronary artery from the pulmonary trunk. Proximal and/or distal hypoplasia of the left coronary artery was frequently observed on gross examination. Histopathologic study of this artery in selected specimens showed slight hypoplasia of the media without significant development of intimal cushions. These observations suggest developmental irnmaturity'P" and, when present, could account for or contribute to manifestations of reperfusion injury after operation. They are consistent with the findings of other authors" but were not a constant feature in our autopsy specimens.
Volume 98 Number 1 July 1989
So-caIled "minor" vanations of the right coronary artery included high take-off and sandwiching of the proximal portion between the aortic and pulmonary roots. Even in normal hearts, sandwiching of the main left coronary artery between the aortic and pulmonary roots, a consequence of abnormal take-off, can result in myocardial ischemia.i'v" This would be of equal hemodynamic importance in the right coronary artery when the left arises from the pulmonary trunk. Other specimens exhibited an abnormal shape of the right coronary arterial orifice, which appeared to result from the hemodynamic disturbances leading to dilatation of the artery. Dilatation was age related, being seen only in the older patients. A consequence of the dilatation was abnormal convolution, as described by Jurishica," who considered this to be a common feature. The effect in our oldest patient was multiple areas for potential constriction of the lumen and turbulence of blood flow where angulation was increased. Selective right coronary artery angiography has been advocated in these patients to demonstrate the dilated right coronary artery and subsequent late fiIling of the anomalous left coronary artery." Dilation of the right coronary artery, however, was found in only six of our specimens (42.8%). Furthermore, ostial stenosis of the right coronary artery and hypoplasia of the artery, both of which were observed, could also be important, by limiting coIlateral flow. Detailed knowledge of the morphology as presently described is not generally available preoperatively in a smaIl infant with an anomalous left coronary artery. However, these findings may help to emphasize the importance of choosing wisely among the several available techniques of repair and by alerting the operating surgeon to potential hazards. The absence of significant coIlateral vessels in this series of hearts probably reflects, to a degree, selection of natural nonsurvivors, but such patients would have been unlikely to tolerate ligation of the left coronary artery." Moreover, some patients also had hypoplasia of the right coronary artery or stenosis of its ostium. This vessel, therefore, cannot be considered a reliable source of coIlateral blood flow to the left ventricle. For this reason and because of the possible technical difficulty of later bypass grafting to a hypoplastic and thin-waIled left coronary artery, initial surgical management should be directed toward primary reconstitution of an arterial system supplied through two coronary arteries. A right coronary artery that arises above the sinotruncal bar, or that lies between the aorta and pulmonary trunk, is at risk of trauma during creation of an aortopulmonary window in the "tunnel" operation.
Anomalous origin of left coronary artery
23
Indeed, one of the surgicaIly treated hearts in this collection came from a patient whose right coronary artery had been occluded by sutures placed to control hemorrhage from the aortopulmonary anastomosis. A high or rising right coronary artery might also lie close to a transverse aortotomy if this were used in the technique of coronary arterial transfer. The proximity of the anomalous left coronary ostium to a commissure of the pulmonary valve, a frequent finding in our specimens, may complicate either the tunnel or transfer operations. In the former, the tunnel, if sutured close to the commissure, can interfere with movement of the leaflet. In the latter, it may be necessary to excise part of the waIl supporting the commissure to obtain a sufficient "button" for reimplantation. Should this occur, short-term results suggest that reattachment of the commissure to the pericardia I patch used to repair the pulmonary trunk provides satisfactory treatment. Although it would seem that the distance to the empty sinus and the length of left coronary artery available for mobilization should be important considerations in the reimplantation operation, this has not been substantiated by our clinical experience. In fact, an artery found taking origin from the nonfacing pulmonary sinus was recently transferred successfuIly to the left aortic sinus in a 6-week-old infant. The success of this operation may be due, in part, to the elasticity of young tissues and, in part, to generous excision of the surrounding sinus of the pulmonary trunk. This pulmonary sinus, in effect, becomes the proximal left coronary artery and thus elongates the vessel. There can be no doubt, however, that reimplantation alters both the shape of the left coronary orifice and the angle it subtends with the aorta. The clinical significance of these changes awaits further foIlow-up of survivors and the development and application of sophisticated methods to study coronary arterial blood flow and ventricular function in small children and infants. We are grateful to Professor D. I. Hamilton and Professor M. Yacoub for allowing us to include their cases. We are indebted for the helpgiven to us by Gwen Connell and for the illustrations by Ken Walters, Helena Wright, and Ann Pownall. We thank Sandra Longworth for typing the manuscript. We appreciate the participation by Professor G. Thiene and Dr. C. E. Godinho in the early discussions. REFERENCES J. Wright NL, Baue AE, Baum S, Blakemore WS, Zinsser
HF. Coronary artery stealdue to anomalous left coronary artery originating from the pulmonary artery. J THORAC CARDIOVASC SURG 1970;59:461-7.
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2. Bland EF, White PO, Garland J. Congenital anomalies of the coronary arteries: report of an unusual case associated with cardiac hypertrophy. Am Heart J 1933;8:787-801. 3. Brooks H StJ. Two cases of abnormal coronary of heart. J Anat Physiol 1886;20:26. 4. Moodie OS, Fyfe 0, Gill CC, et al. Anomalous origin of the left coronary artery from the pulmonary artery (Bland- White-Garland syndrome) in adult patients: longterm follow-up after surgery. Am Heart J 1983; 106: 381-8. 5. Hamilton 01, Ghosh PK, Donnelly RJ. An operation for anomalous origin of the left coronary artery. Br Heart J 1979;41: 121-4. 6. Goldberger E. Angiocardiographic diagnosis of an anomalous coronary artery originating from the pulmonary artery. Am J Cardiol 1960;6:694. 7. Edwards JE. The direction of blood flow in coronary arteries arising from the pulmonary trunk [Editorial]. Circulation 1964;29: 163-6. 8. De la Cruz MV, Anselmi G, Romero A, Monroy G. A qualitative study of the ventricles and great vessels of normal children. Am Heart J 1960;5:675-90. 9. Gittenberger-de Groot AC, Sauer U, OppenheimerDekker A, Quaegebeur J. Coronary arterial anatomy in transposition of the great arteries: a morphologic study. Pediatr Cardiol 1983;4: 15-23. 10. Vlodaver Z, Neufeld HN, Edwards JE. Histologic patterns of the coronary arteries in children. In: Coronary arterial variations in the normal heart and in congenital heart disease. New York: Academic Press, 1975:135-45. II. Sekiguchi M, Hiroe M, Morimoto S. On the standardization of histopathological diagnosis and semiquantitative assessment of the endomyocardium obtained by endomyocardial biopsy. Bull Heart Inst Jpn 1979-80;55-85. 12. Yonesaka S, Becker AE. Dilated cardiomyopathy; diagnostic accuracy of endomyocardial biopsy. Br Heart J 1987;58: 156-61. 13. McAlpine W A. The coronary arteries. In: Heart and coronary arteries. Section III. Berlin; Springer Verlag, 1975:133-50.
The Journal of Thoracic and Cardiovascular Surgery
14. Noren GR, Raghib G, Moller JH, Amplatz K, Adams P, Edwards JE. Anomalous origin of the left coronary artery from the pulmonary trunk with special reference to the occurrence of mitral insufficiency. Circulation 1964; 30:171-9. 15. Burchell HB, Brown AL. Anomalous origin of coronary artery from pulmonary artery masquerading as mitral insufficiency. Am Heart J 1962;63:388-93. 16. Ogden JA: Congenital anomalies of the coronary arteries. Am J Cardiol 1970;25:474-9. 17. Becker AE. Congenital malformations of the coronary arteries. In: Anderson RH, Neches WH, Park SC, Zuberbuhler JR, eds. Perspectives in pediatric cardiology. Mount Kisco, New York: Futura Press, 1988:369-78. 18. Steussy HF, Caldwell RL, Wills ER, Waller BF. High take-off of the left main coronary artery from the pulmonary trunk: potentially fatal combination with pulmonary trunk banding. Am Heart J 1984; 108:619- 21. 19. Bellhouse BJ, Bellhouse FH, Reid KG. Fluid mechanics of the aortic root with application to coronary flow. Nature 1968;219: 1059-61. 20. Moon HD. Coronary arteries in fetuses, infants and juveniles. Circulation 1957; 16:263-7. 21. Liberthson RR, Dinsmore RE, Bharati S, et al. Aberrant coronary artery origin from the aorta: diagnosis and clinical significance. Circulation 1974;50:774-9. 22. Kimbiris 0, Iskandrian AS, Segal BL, Bemis CEo Anomalous aortic origin of coronary arteries. Circulation 1978;58:606-15. 23. Jurishica AJ. Anomalous left coronary artery: adult type. Am Heart J 1957;54:429-36. 24. Menahem S, Venables AW. Anomalous left coronary artery from the pulmonary artery: a 15 year sample. Br Heart J 1987;58:378-84. 25. Kirklin JW, Barratt-Boyes B. Cardiac surgery: morphology, diagnostic criteria, natural history, techniques, results and indications. New York, John Wiley, 1986:963.
THORAC CARDIOVASC SURG
1989;98:16-24
Anomalous origin of the left coronary artery from the pulmonary trunk Anatomic findings in relation to pathophysiology and surgical repair Anomalous origin of the left coronary artery from the pulmonary trunk, though a discrete anatomic malfonnation, manifests a spectrum of clinical and pathologic consequences, The objectives of this study were to characterize the primary anatomic findings in a group of specimens with anomalous left coronary artery and the extent of secondary morphologic and pathologic changes. Although the cases studied probably represent the least favorable end of the spectrum, the observed pathogenesis and evolution of secondary changes suggest that reconstruction of a two-coronary arterial system supplied through two coronary arteries would be advantageous to most patients. A high origin of the right coronary artery or location of the left coronary artery adjacent to a pulmonary cusp or branch may complicate the tunnel-type repair. In these cases, transfer of the left coronary artery to the aorta may be preferable.
Audrey Smith, FIMLS, MPhil, PhD; Robert Arnold MB, ChB, FRCP, FRCPE; Robert H. Anderson, BSc, MD, FRCPath,b James L. Wilkinson, MB, ChB, FRCP; Shakeel A. Qureshi, MB, ChB, MRCP; Leon M. Gerlis, MB, BS, FRCPath,b and Roxane McKay, BA, MD, FRCS; Liverpool and London, England
Anomalous origin of the left coronary artery from the pulmonary trunk can be considered as an anatomicclinical spectrum with two extremes, the "infantile" and the "adult." In the adult type, the collateral circulation between the right and left coronary systems is sufficiently well formed to provide a shunt from the right coronary artery via the anomalous left coronary artery to the pulmonary trunk.' In the infantile type, the collateral circulation is either poorly developed or of unfavorable distribution. In consequence, the patients have angina-like episodes and left ventricular failure
From the Institute of Child Health, University of Liverpool, Royal Liverpool Children's Hospital Alder Hey, Liverpool, England,' and the Department of Paediatric Cardiac Morphology, Cardiathoracic Institute, Brompton Hospital, London, England." Professor R. H. Anderson and Dr. L. M. Gerlis are supported by the British Heart Foundation. Dr. Audrey Smith was supported by the National Heart Research Fund at the commencement of this work but is currently supported by the Endowment Fund of the Royal Liverpool Children's Hospitals. Received for publication April 5, 1988. Accepted for publication Nov. 30, 1988. Address for reprints: Audrey Smith, PhD, Institute of Child Health, University of Liverpool, Royal Liverpool Children's Hospital Alder Hey, Eaton Road, Liverpool, Ll2 2AP, England.
16
because of myocardial ischemia. Although the syndrome is associated eponymously with Bland, White, and Garland,' the first case was recognized clinically in
1885.3 The physiologic manifestations evolve through several stages, reflecting the prevailing hemodynamic environments in the systemic and pulmonary circulations. In the fetus, the left coronary artery fills antegradely from the pulmonary trunk in which the pressure is equal to that in the aorta. After birth, myocardial perfusion depends on the extent of the collateral circulation and the rate of decline of the pulmonary arterial resistance. Row in the left coronary artery is usually reversed. Myocardial damage then follows as a result of the low pressure of coronary arterial perfusion. If the patient survives, further collateral arteries develop in response to myocardial hypoxia, which sets the scene for evolution of a "coronary arterial steal" syndrome.' In this situation the fistulous flow into the pulmonary trunk may become so large that the anastomoses lose their nutritive function and cause further myocardial damage. The physiologic consequences of poor coronary arterial perfusion and myocardial ischemia show a wide range of individual variation and have been well assessed and investigated clinically."? In contrast, the gross anatomic and histopathologic features that reflect the extent of myocardial
Volume 98 Number 1
Anomalous origin of left coronary artery
July 1989
I7
damage and length of survival have rarely been studied. With this in mind, we have inspected examples of this lesion in our autopsy collection, aiming also to define those anatomic characteristics of the lesion that could be of surgical significance. Materials and methods We studied 14 hearts with anomalous origin of the left coronary artery from the pulmonary trunk. The age range of the patients from whom the hearts were retrieved was from II weeks to 14 years. Two had undergone surgical treatment. Measurements taken with vernier calipers were recorded with other data on standard forms. These data were compared with the normal values given by De la Cruz and associates.' The aortic sinuses were designated as right hand (or No. I). left hand (or No.2), and nonfacing, according to the view obtained from the nonfacing aortic sinus looking toward the pulmonary trunk' (Fig. I). The sinuses of the pulmonary valve were designated right hand (or No. I) and left hand (or No.2) in similar fashion as viewed from the nonfacing sinus of the pulmonary trunk toward the aorta. Thus the left-hand aortic sinus faces the right-hand pulmonary sinus and vice versa. The size and exact location of the orifices of both right and left coronary arteries were noted in relation to the bar between the sinusal and truncal components of the great arteries and to the commissures of the arterial valves (Fig. 2, a and b). A pin was inserted from the aorta through the center of the empty left-hand sinus (No.2) just above the aortic bar. The distance was then measured between the emergence of the pin on the outside of the aorta and the posterior aspect of the anomalous left coronary artery. The length of the main stem of the left coronary artery was also measured (Fig. 3). The morphology' of each coronary arterial orifice was examined and compared with that of a series of 10 hearts from otherwise normal neonates and infants who had died of noncardiac causes. The angle subtended by each proximal coronary artery to the long axis of its arterial trunk was approximated and compared with the same data from the normal hearts. The distribution and caliber of the main coronary arteries and branches were recorded. Coronary arteries were deemed to be hypoplastic either if there was a uniformly long segment with a narrow lumen" or if they appeared to be disproportionately small for the size of the ventricle by comparison with normal arteries. They were not considered to be dilated unless conspicuously larger than normal. Blocks of myocardium for histologic examination were removed from the anterolateral wall of the right ventricles and the anterior and posterior walls and apexes of the left ventricles of all the specimens. Blocks for microscopic study were also removed from the right and left coronary arteries of three selected specimens. Sections were stained by Mayer's hematoxylin and eosin stain and by Weigert's elastin stain with van Giesen's counterstain. The changes in the tissue were described as slight (+). moderate (++). or severe (+++) according to the semiquantitative scheme applied by Sekiguchi, Hiroe, and Morimoto" and Yonesaka and Becker."
Findings All the hearts had usual (solitus) atrial arrangement with concordant atrioventricular and ventriculoarterial connections. A moderately large perimembranous ventricular septal defect with malalignment of the outlet
A
AD
Fig. 1. The aortic and pulmonary valves from above in their normal spatial relationship, that is, right posterior to left anterior. The enumeration of the aortic and pulmonary valve sinuses in relation to the nonfacing sinuses is indicated. Sinus I is to the right hand and sinus 2 is to the left hand when viewing the opposite great artery from the non facing sinus. A. Anterior: Ao. aorta: AD. anterior descending (interventricular) artery; C. circumflex artery; L. left; LMCA. main stem of the left coronary artery: NF. non facing sinus; P, posterior; PT, pulmonary trunk; R. right; RCA. right coronary artery.
septum was present in one heart, together with a defect of the oval fossa. The oval fossa was patent in two hearts and was fenestrated in one. The atrial septum was intact in the remaining hearts. The arterial duct was probe patent in two cases. Coarctation of the aorta existed in one specimen. In another heart the pulmonary valve had two leaflets. The size of both the aortic and pulmonary valves was normal throughout the series. The anomalous left coronary artery originated in association with the right-hand facing pulmonary sinus (I) in all the specimens. The commissures between the facing aortic and pulmonary sinuses opposed each other directly in each of the hearts (including the specimen in which the pulmonary valve had two leaflets). Morphology of the sinuses of the arterial valves, the coronary arterial orifices, and the proximal coronary arteries. The right coronary arterial orifice was always funnel-shaped in the normal hearts, with the larger circular end of the funnel opening from the aortic lumen. The narrow end determined the luminal diameter of the proximal right coronary artery. The angle subtended to the aortic root was approximately 90 degrees. The main stem of the left coronary artery originated with parallel walls from its aortic orifice, which was always elliptic in the normal heart. The luminal diameter stayed constant until the bifurcation. This artery always subtended an acute angle to the main axis of the aortic root in the normal group. The
The Journal of
18
Thoracic and Cardiovascular
Smith et al.
Surgery
a ABNORMAL
NORMAL
CD
CD 0@ ,,
\NF AORTIC VALVE
2)
5
CDCD/ r\NF 1
~cl'
R+L P
AORTIC VALVE
A
b
ABNORMAL
NORMAl.
0@
-i~'\U
NF,'
//
2
AORTIC VALVE
,
\NF
" 1
".
PULMONARY VALVE
Fig. 2. a, Right coronary artery origin (circles) in relation to right-hand aortic facing sinus (No. I) in the normal series and to both aortic sinuses (No.1 and No.2) in the abnormal series. Numbers inside the circles indicate the incidence in each location. In the abnormal group there are two hearts in which the right coronary artery takes a high origin. one of these being above the left-hand aortic facing sinus (No.2). b, Left coronary artery origin (circles) in the normal and the abnormal series. In the normal series the left coronary artery always takes origin in relation to the left-hand aortic facing sinus (No. 2), whereas in the abnormal series it takes origin in relation to the right-hand pulmonary facing sinus (No. 1). In three of these hearts, the origin was high above the bar between the sinus and truncal portion of the pulmonary trunk. The orifice impinged on a commissure in five specimens. NF. Nonfacing sinus.
combination of angulation in both vertical and horizontal planes produced a spur in the margins of its orifice. Descriptions of such anatomic characteristics in normal hearts have been recorded by McAlpine." The funnel shape was observed in only seven of the right coronary arterial orifices in the abnormal heart series (50%). The lumen in the remainder was either the same size as that of the orifice (six hearts 43%) or else larger (one heart, 7%). The right coronary artery in 11 abnormal hearts connected at a normal angle with the aortic root, but in another two abnormal hearts its origin was high above the sinotruncal bar (2 mm and 8 mm,
Fig. 3. The distance (Y) that was measured between the midpoint of the empty aortic sinus (No.2) and the posterior aspect of the main stem of the left coronary artery from its anomalous origin in pulmonary sinus NO.1. The length of main stem of the left coronary artery before its branching is also indicated (Z). A. Anterior; AD. anterior descending (interventricular) artery; Ao. aortic valve; C. circumflex artery; L. left; LMCA. main left coronary artery; NF. nonfacing sinus; P. posterior; PT. pulmonary trunk; R. right; RCA. right coronary artery.
respectively). The first of these was stenotic (Fig. 4). Both had a spur in the margin, which was reminiscent of the normal arrangement of the orifice of the left coronary artery. The proximal portion of the right coronary artery ran between the aortic and pulmonary roots in the second specimen. The right coronary artery was grossly convoluted in the remaining heart, its proximal portion being directed cranially for 10 mm (Fig. 5). In the normal hearts, neither coronary arterial orifice impinged on a commissure (Fig. 2). In contrast, although the orifices of the right coronary arteries were always clear of the commissures of the aortic valve (Fig. 2, a), in five abnormal hearts the origin of the anomalous left coronary artery was either very close to or directly impinged on a commissure of the pulmonary valve (Fig. 2, b. and Fig. 6). In a further three hearts, the orifice of the aberrant left coronary artery was displaced 3 or 4 mm above the sinopulmonary bar (Fig. 2, b). The left cor.' rary arterial orifice impinged on the origin of the right pulmonary artery in one of these (Fig. 7). The characteristic spur seen at the margins of the orifice of the normal left coronary artery was absent from the aberrant left coronary artery in four hearts from the group that were not treated surgically. These orifices were circular rather than elliptic.
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Anomalous origin of left coronary artery
July 1989
19
, 1!'"
RA RV Fig. 4. Right superior oblique view of a stenosed orifice of the right coronary artery (arrow). The aortic trunk has been opened into the orifice to enlarge it. Ao, Aorta; i, infundibular branch: RA. right atrium; rc, right coronary artery; RV, right ventricle. The comparable size of coronary arterial orifices is indicated in Table I. The angle subtended by the main stem of the left coronary artery relative to the pulmonary trunk was less constant in the abnormal hearts than that of the main stem to the aorta (Table II). The distance between the midpoint of the empty left-hand aortic sinus (No.2) and the posterior aspect of the aberrant left coronary artery varied from 2 to 18 mm (Fig, 3), The length of artery before its branch point (in other words, that length which would have been available for surgical mobilization) ranged from 2 to 12 mm (the comparable value in the normal series was from 1 to 5 mm). These measurements were not related to age, nor was the length of artery available for mobilization related to the distance between its origin from the pulmonary artery and the empty aortic sinus (Fig. 3). In 12 of the abnormal hearts, the right coronary artery gave rise to the posterior interventricular artery. As described earlier, this artery and its branches were conspicuously dilated and convoluted in the oldest patient (Fig. 5). The artery of the second oldest patient was similarly but less markedly convoluted. In another four hearts from younger patients, the right coronary artery and some or all of its branches were dilated but showed lesser degrees of convolution.
Fig. 5. The dashed line indicates the tortuous course of the dilated right coronary artery. Ao. Aorta; RA. right atrium; RV, right ventricle.
Fig. 6. The anomalousoriginof the left main coronary artery below the sinopulmonary bar, impinging on the commissure between pulmonary sinuses 1 and 2 (arrow). PT, Pulmonary trunk; R V, right ventricle.
Despite the abnormal connection of the left coronary artery, its subsequent course and branching pattern were normal. The caliber and length, however, were extremely variable. The left coronary artery extended to supply a poorly developed posterior interventricular branch in two hearts. The right coronary artery was also hypoplastic in
20
The Journal of Thoracic and Cardiovascular Surgery
Smith et al.
Fig. 7. The anomalous origin of the left main coronary artery (arrow) is seen at the branch point of the right pulmonary
artery. L, Left pulmonary artery; PT. pulmonary trunk; R. right pulmonary artery; RV. right ventricle.
Table I. Size of right coronary arterial orifices compared with left* No. of specimens Comparable size Right> left Right < left
Normal series
Abnormal series
10 10
12 7
2
Fig. 8. Arrows indicate a collateral artery. It runs anteriorly to the pulmonary root from the right coronary artery, under the main left coronary artery, and connects with the left coronary artery at the branching point of the circumflex artery. Ao. Aorta; C circumflex artery; LC left coronary artery; PT, pulmonary trunk; RC right coronary artery.
3
"Two postoperative specimens were not comparable.
these two specimens. In a further four hearts, the caliber of the arterial supply to the entirety of the left ventricle was poor, all the arteries being hypoplastic. In three hearts the distal portions of the circumflex and anterior interventricular branches were narrow, although the proximal segments were of good caliber. The left coronary artery and its branches were of normal dimensions in only five specimens (36%). Collateral arteries. No collateral arteries were visible grossly in 12 of the specimens (85.8%), although a tenuous communication was observed between the anterior interventricular artery and the infundibular or right marginal branches of the right coronary artery in six of these (42.8%). Obvious collateral arteries were seen in only two cases (14.2%). In one of these, a well-developed anomalous proximal branch from the right coronary artery coursed across the subpulmonary infundibulum and anastomosed with the proximal part of the circumflex artery (Fig. 8). Another specimen showed a similar collateral artery coursing across the pulmonary root, anastomosing in this case with the anterior interventricular descending artery.
Table II. Angle of proximal main left coronary artery to main axis of aorta or pulmonary trunk* Number of specimens Acute anteroapical inclination to long axis of aorta or pulmonary trunk Laterally oriented left main coronary artery Posteriorly oriented left main coronary artery
Normal
Abnormal
10
12 8
9
3
*Two postoperative specimens were not comparable.
The artery to the sinus node. The artery to the sinus node originated from the aberrant left coronary artery in three specimens. In all except one of the remaining cases it arose from the right coronary artery. It could not be demonstrated by blunt dissection in the last heart. Pathologic condition of the left ventricle. A spectrum of gross pathologic change was apparent throughout the series, being most obvious in the left ventricle. This chamber was dilated in all hearts from infants with an intact interventricular septum. In those that could be assessed against age (nine hearts), the ventricular inlet
Volume 98 Number 1 July 1989
Anomalous origin of left coronary artery
2I
Fig. 9. a, The dilated, thin-walled left venticle of a heart with anomalous origin of the left coronary artery from the pulmonary trunk. The mitral valve is small and both anterolateral and posteromedial papillary muscles are hypoplastic. The root of the posteromedial papillary muscle (large open arrow) is seen to be well above the apex of the ventricle. The corda I attachments are unduly long (black arrow). Interstitial fibrosis is present at the root of the anterolateral papillary muscle (curved open arrow). b, The left ventricle of a normal heart for comparison with a, showing the root of the posteromedial papillary muscle (arrow) to be close to the apex of the ventricle. A. Apex; AL. anterolateral papillary muscle; Ao. aorta; MV. mitral valve; PM. posteromedial papillary muscle.
and outlet dimensions were greater than published normal mean values" (p < 0.001). Generalized thinning of the left ventricular apex was observed in four specimens, and localized thinning (aneurysmal) was found in two others, being duplicated in one. The left ventricular wall was hypertrophied in two hearts, one with dilatation of the cavity and the other without. The circumference of the mitral valve could be assessed against age in I I hearts. It was below the minimum end of the normal range" in two specimens, within the normal range in five, and larger in the remaining four hearts. The overall differences were not significant when compared with normal values. On the other hand, both anterolateral and posteromedial papillary muscles were small for the size of the left ventricle in 12 specimens (85.8%, Fig. 9, a and b). The characteristics of these muscles ranged from short to hypoplastic, with ventricular attachments well above the apex (Fig. 9, a). They were frankly atrophic in two hearts. The tendinous cords were unduly long in four of the specimens with average or small mitral valves, and the leaflet material was thickened and dysplastic in one case, again with a small valve. Macroscopic evidence of endocardial thickening and
subendocardial sclerosis was seen in seven different specimens. Gross infarction was observed in two hearts but extended only into the inner third of the myocardium. Histology. Histologic features indicating chronic myocardial ischemia included endocardial thickening, interstitial fibrosis, and calcification (Table III). Recent acute ischemia was shown by myocytic degeneration and fragmentation, sometimes accompanied by cellular infiltration. No abnormalities were observed in any of the blocks taken from the right ventricle, but ischemic changes were present in the blocks from the left ventricle of all specimens with anomalous origin of the left coronary artery. These changes ranged from mild to severe. They varied from case to case and from one myocardial region to another. The overall degree of severity showed no relationship to the age of death. Endocardial thickening, with noted increase in fibrous and elastic tissue, was observed in hearts from all but the oldest patients. In no case was it regarded as severe and, in this series, it never resembled endocardial fibroelastosis. The endocardial thickening was slightly more marked in the apex than in the anterior wall. The posterior wall was least affected. The changes tended to
22
The Journal of Thoracic and Cardiovascular Surgery
Smith et al.
Table
m Interstitial Fibrosis
Endocardial thickening Age II wk
3 rna 3 rna 6 rna 8 rna 9 rna I yr 7 rna 2 yr 4 yr 9 rna 5 yr 14 yr
P
A
0
++ + ++ + + + ++ ++ +
0
+ ++ + +
Apex
+ + + ++
+ ++ ++ ++ ++ + + ++ +
0 0
0 0
0
Myocyte fragmentation
Penetration offibrosis
Apex
A
P
Apex
A
P
Apex
A
P
+ + ++ ++ ++ + +++ ++ +++ ++ ++
+ + ++ + ++ +++ ++ + ++
+++ + ++ + + ++ ++ + +
+ + ++ + ++ +++ + + ++
+++ + ++ + + ++ ++ + +
+ + + + ++ + + + +
0
0
0 0
+ + + + + + ++ + + ++ +
++ + ++ + ++ + + + +
0
+ + ++ +++ ++ + ++ ++ +++ ++ +++
0
0 0
++
+
++
+
Calcification A
P
Apex
+ + + +
+ +
+
A, Anterior wall; P, posterior wall
be rather more marked in hearts from children under I year of age, but this difference was not statistically significant. Interstitial fibrosis was always maximal toward the endocardial aspect of the ventricular wall. It tended to be most marked in the anterior wall and least marked at the apex. It did not appear to be age related. No instances of acute infarction were noted in the tissue blocks taken from the specified standard. sites. The milder changes observed appeared with equal frequency in different regions of the left ventricle and were not age related. Small areas of dystrophic calcification were present in six cases. These were found apically in two cases, in the anterior wall in three, and in both regions in the remaining heart. These changes were not related to age.
Discussion Left ventricular damage resulting from myocardial ischemia in patients with anomalous origin of the left coronary artery from the pulmonary trunk is associated with a range of pathologic findings. These include endocardial and subendocardial fibrosis, damage to the papillary muscles, patchy myocardial necrosis, and dilatation and formation of aneurysms. Mitral incompetence frequently developsl4,15 and may be associated with leaflet dysplasia, presumably of secondary origin. The extent and severity of these changes is variable and correlates poorly with the age of the patients at death. Development of collateral arterial supply is a vital factor in determining the degree of myocardial ischemia and its consequences. Nonetheless, a number of other anatomic variables may contribute to the evolution of the clinical picture, the severity of ventricular dysfunction,
the extent of myocardial damage, and the outcome of attempts to correct the malformation surgically. It is hard to quantify the influence of the numerous anatomic variations described in this study. These would be catalogued as both major and minor according to the approach suggested by Ogden." The very presence of so many abnormalities, even if "minor" in some cases, attests to this malformation not being a single, simple anatomic malformation of the left coronary artery. As indicated by Becker," it also points to the potential dangers in the simplistic division of coronary arterial malformation into major and minor features. Be that as it may, what is the significance of the additional variables? Minor variations associated with the anomalous left coronary artery included high take-off (Fig. 2, a and b). In the past, when banding of the pulmonary trunk was considered a surgical option, this combination has proved fatal." High take-off of a coronary artery may also affect blood flow. 19 This has been considered important in the etiology of ischemic heart disease. It is likely to be even more significant when perfusion is already compromised by origin of the left coronary artery from the pulmonary trunk. Proximal and/or distal hypoplasia of the left coronary artery was frequently observed on gross examination. Histopathologic study of this artery in selected specimens showed slight hypoplasia of the media without significant development of intimal cushions. These observations suggest developmental irnmaturity'P" and, when present, could account for or contribute to manifestations of reperfusion injury after operation. They are consistent with the findings of other authors" but were not a constant feature in our autopsy specimens.
Volume 98 Number 1 July 1989
So-caIled "minor" vanations of the right coronary artery included high take-off and sandwiching of the proximal portion between the aortic and pulmonary roots. Even in normal hearts, sandwiching of the main left coronary artery between the aortic and pulmonary roots, a consequence of abnormal take-off, can result in myocardial ischemia.i'v" This would be of equal hemodynamic importance in the right coronary artery when the left arises from the pulmonary trunk. Other specimens exhibited an abnormal shape of the right coronary arterial orifice, which appeared to result from the hemodynamic disturbances leading to dilatation of the artery. Dilatation was age related, being seen only in the older patients. A consequence of the dilatation was abnormal convolution, as described by Jurishica," who considered this to be a common feature. The effect in our oldest patient was multiple areas for potential constriction of the lumen and turbulence of blood flow where angulation was increased. Selective right coronary artery angiography has been advocated in these patients to demonstrate the dilated right coronary artery and subsequent late fiIling of the anomalous left coronary artery." Dilation of the right coronary artery, however, was found in only six of our specimens (42.8%). Furthermore, ostial stenosis of the right coronary artery and hypoplasia of the artery, both of which were observed, could also be important, by limiting coIlateral flow. Detailed knowledge of the morphology as presently described is not generally available preoperatively in a smaIl infant with an anomalous left coronary artery. However, these findings may help to emphasize the importance of choosing wisely among the several available techniques of repair and by alerting the operating surgeon to potential hazards. The absence of significant coIlateral vessels in this series of hearts probably reflects, to a degree, selection of natural nonsurvivors, but such patients would have been unlikely to tolerate ligation of the left coronary artery." Moreover, some patients also had hypoplasia of the right coronary artery or stenosis of its ostium. This vessel, therefore, cannot be considered a reliable source of coIlateral blood flow to the left ventricle. For this reason and because of the possible technical difficulty of later bypass grafting to a hypoplastic and thin-waIled left coronary artery, initial surgical management should be directed toward primary reconstitution of an arterial system supplied through two coronary arteries. A right coronary artery that arises above the sinotruncal bar, or that lies between the aorta and pulmonary trunk, is at risk of trauma during creation of an aortopulmonary window in the "tunnel" operation.
Anomalous origin of left coronary artery
23
Indeed, one of the surgicaIly treated hearts in this collection came from a patient whose right coronary artery had been occluded by sutures placed to control hemorrhage from the aortopulmonary anastomosis. A high or rising right coronary artery might also lie close to a transverse aortotomy if this were used in the technique of coronary arterial transfer. The proximity of the anomalous left coronary ostium to a commissure of the pulmonary valve, a frequent finding in our specimens, may complicate either the tunnel or transfer operations. In the former, the tunnel, if sutured close to the commissure, can interfere with movement of the leaflet. In the latter, it may be necessary to excise part of the waIl supporting the commissure to obtain a sufficient "button" for reimplantation. Should this occur, short-term results suggest that reattachment of the commissure to the pericardia I patch used to repair the pulmonary trunk provides satisfactory treatment. Although it would seem that the distance to the empty sinus and the length of left coronary artery available for mobilization should be important considerations in the reimplantation operation, this has not been substantiated by our clinical experience. In fact, an artery found taking origin from the nonfacing pulmonary sinus was recently transferred successfuIly to the left aortic sinus in a 6-week-old infant. The success of this operation may be due, in part, to the elasticity of young tissues and, in part, to generous excision of the surrounding sinus of the pulmonary trunk. This pulmonary sinus, in effect, becomes the proximal left coronary artery and thus elongates the vessel. There can be no doubt, however, that reimplantation alters both the shape of the left coronary orifice and the angle it subtends with the aorta. The clinical significance of these changes awaits further foIlow-up of survivors and the development and application of sophisticated methods to study coronary arterial blood flow and ventricular function in small children and infants. We are grateful to Professor D. I. Hamilton and Professor M. Yacoub for allowing us to include their cases. We are indebted for the helpgiven to us by Gwen Connell and for the illustrations by Ken Walters, Helena Wright, and Ann Pownall. We thank Sandra Longworth for typing the manuscript. We appreciate the participation by Professor G. Thiene and Dr. C. E. Godinho in the early discussions. REFERENCES J. Wright NL, Baue AE, Baum S, Blakemore WS, Zinsser
HF. Coronary artery stealdue to anomalous left coronary artery originating from the pulmonary artery. J THORAC CARDIOVASC SURG 1970;59:461-7.
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Smith et al.
2. Bland EF, White PO, Garland J. Congenital anomalies of the coronary arteries: report of an unusual case associated with cardiac hypertrophy. Am Heart J 1933;8:787-801. 3. Brooks H StJ. Two cases of abnormal coronary of heart. J Anat Physiol 1886;20:26. 4. Moodie OS, Fyfe 0, Gill CC, et al. Anomalous origin of the left coronary artery from the pulmonary artery (Bland- White-Garland syndrome) in adult patients: longterm follow-up after surgery. Am Heart J 1983; 106: 381-8. 5. Hamilton 01, Ghosh PK, Donnelly RJ. An operation for anomalous origin of the left coronary artery. Br Heart J 1979;41: 121-4. 6. Goldberger E. Angiocardiographic diagnosis of an anomalous coronary artery originating from the pulmonary artery. Am J Cardiol 1960;6:694. 7. Edwards JE. The direction of blood flow in coronary arteries arising from the pulmonary trunk [Editorial]. Circulation 1964;29: 163-6. 8. De la Cruz MV, Anselmi G, Romero A, Monroy G. A qualitative study of the ventricles and great vessels of normal children. Am Heart J 1960;5:675-90. 9. Gittenberger-de Groot AC, Sauer U, OppenheimerDekker A, Quaegebeur J. Coronary arterial anatomy in transposition of the great arteries: a morphologic study. Pediatr Cardiol 1983;4: 15-23. 10. Vlodaver Z, Neufeld HN, Edwards JE. Histologic patterns of the coronary arteries in children. In: Coronary arterial variations in the normal heart and in congenital heart disease. New York: Academic Press, 1975:135-45. II. Sekiguchi M, Hiroe M, Morimoto S. On the standardization of histopathological diagnosis and semiquantitative assessment of the endomyocardium obtained by endomyocardial biopsy. Bull Heart Inst Jpn 1979-80;55-85. 12. Yonesaka S, Becker AE. Dilated cardiomyopathy; diagnostic accuracy of endomyocardial biopsy. Br Heart J 1987;58: 156-61. 13. McAlpine W A. The coronary arteries. In: Heart and coronary arteries. Section III. Berlin; Springer Verlag, 1975:133-50.
The Journal of Thoracic and Cardiovascular Surgery
14. Noren GR, Raghib G, Moller JH, Amplatz K, Adams P, Edwards JE. Anomalous origin of the left coronary artery from the pulmonary trunk with special reference to the occurrence of mitral insufficiency. Circulation 1964; 30:171-9. 15. Burchell HB, Brown AL. Anomalous origin of coronary artery from pulmonary artery masquerading as mitral insufficiency. Am Heart J 1962;63:388-93. 16. Ogden JA: Congenital anomalies of the coronary arteries. Am J Cardiol 1970;25:474-9. 17. Becker AE. Congenital malformations of the coronary arteries. In: Anderson RH, Neches WH, Park SC, Zuberbuhler JR, eds. Perspectives in pediatric cardiology. Mount Kisco, New York: Futura Press, 1988:369-78. 18. Steussy HF, Caldwell RL, Wills ER, Waller BF. High take-off of the left main coronary artery from the pulmonary trunk: potentially fatal combination with pulmonary trunk banding. Am Heart J 1984; 108:619- 21. 19. Bellhouse BJ, Bellhouse FH, Reid KG. Fluid mechanics of the aortic root with application to coronary flow. Nature 1968;219: 1059-61. 20. Moon HD. Coronary arteries in fetuses, infants and juveniles. Circulation 1957; 16:263-7. 21. Liberthson RR, Dinsmore RE, Bharati S, et al. Aberrant coronary artery origin from the aorta: diagnosis and clinical significance. Circulation 1974;50:774-9. 22. Kimbiris 0, Iskandrian AS, Segal BL, Bemis CEo Anomalous aortic origin of coronary arteries. Circulation 1978;58:606-15. 23. Jurishica AJ. Anomalous left coronary artery: adult type. Am Heart J 1957;54:429-36. 24. Menahem S, Venables AW. Anomalous left coronary artery from the pulmonary artery: a 15 year sample. Br Heart J 1987;58:378-84. 25. Kirklin JW, Barratt-Boyes B. Cardiac surgery: morphology, diagnostic criteria, natural history, techniques, results and indications. New York, John Wiley, 1986:963.