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Origin of the Left Coronary Artery From the Right Pulmonary Artery

SAROJA BHARATI, MD, FACC,* NAKUL CHANDRA, MD,t LAWRENCE W. STEPHENSON, MD,t

HENRY R. WAGNER, Mot, PAUL M. WEINBERG, MD, FACC,:!: MAURICE LEV, MD, FACC*

Brown Mills and Neptune, New Jersey. Philadelphia and Hershev, Pennsylmnia

Origin of the left coronary artery from the right pul­monary artery has rarely been documented. This is thefirst such case in a heart with an intact ventricular sep­tum and paraductal coarctation of the aorta. Althoughan antemortem diagnosis was made and the anomalousleft coronary artery was ligated, the patient, a 3V2 month

Origin of the left coronary artery from the right or leftpulmonary artery is extremely rare. To date, we have foundfour reported cases (1-4). In three cases, the left coronaryartery arose from the right pulmonary artery: in associationwith tetralogy of Fallot (I), ventricular septal defect (2) andcommon atrioventricular canal, aortic stenosis, patent duc­tus arteriosus and coarctation of the aorta (3). In a fourthcase, in a patient with truncus arteriosus type II, the leftcoronary artery arose from the left pulmonary artery (4),

This report concerns a case of origin of the left coronaryartery from the right pulmonary artery, associated withcoarctation of the aorta and intact ventricular septum. Webelieve that the case merits documentation because of itssurgical import,

Case ReportThis 31f2 month old Caucasian boy was the full-term

product of a pregnancy complicated by maternal hyperten­sion. He was born by caesarean section for breech presen­tation to a 28 year old female. At 3 weeks of life, he was

From Congenital Heart and Conduction System Laboratory, Depart­ment of Pathology, Deborah Heart and Lung Center, Browns Mills, NewJersey:* Jersey Shore Medical Center, Neptune, New Jersey:t Departmentsof Pathology and Pediatrics, University of Pennsylvania, Philadelphia,Pennsylvania:\:: and Departments of Pathology, Temple University MedicalSchool* and Pennsylvania State University Medical School*, The MiltonS. Hershey Medical Center, Hershey, Pennsylvania. This study was aidedby Grant HL 30558-01 from National Heart, Lung, and Blood Institutes,the National Institutes of Health, Bethesda, Maryland. Manuscript receivedOctober 31, 1983; revised manuscript received December 13, 1983, ac­cepted December 15, 1983.

Address for reprints: Saroja Bharati, MD, Congenital Heart and Con­duction System Laboratory, Department of Pathology, Deborah Heart andLung Center, Browns Mills, New Jersey 08015-1799,

,[') 1984 by the American College of Cardiology

old infant, died 1 day after surgery. Autopsy confirmedthe diagnosis, but revealed that the left coronary arterywas dominant. It is believed that the fatal outcome inthe infant was, in part, due to the dominance of the leftcoronary artery and the effects of the coarctation on thealready ischemic left ventricle.

noted to be feeding poorly despite formula changes and hehad multiple shuddering and crying episodes. No cyanosiswas noted. One week before admission to the hospital, hedeveloped a dry hacking cough and was treated with anti­biotics. Four days before admission, he began to have ep­isodes of coughing spells, crying and breath-holding. Hewas taken to a local hospital where a chest X-ray film showeda large heart. An electrocardiogram (Fig. I) showed anelevated ST-T wave segment in leads V5 and V6 and 6 mmQ waves in leads II, III and aVF, compatible with infarctionof anterolateral and inferior left ventricular walls. The echo­cardiogram revealed severe left ventricular dilation and poorcontractility.

An aortogram revealed the right coronary artery emerg­ing from the aorta (Fig. 2A), which was considered to beof good size. An anomalous left coronary artery emergedfrom the right pulmonary artery (Fig. 2B).

Cardiac catheterization and angiography showed poorleft ventricular contractility with markedly elevated left ven­tricular end-diastolic pressure (12 mm Hg) and coarctationof the aorta. However, there was no systolic pressure gra­dient across the narrowed isthmus, probably because ofreduced cardiac output. The pulmonary artery pressure waselevated (45110 mm Hg, mean 40) and there was no step­up in oxygen saturation at the pulmonary artery leveL

The infant was transferred to the Children's Hospital ofPhiladelphia. On admission, physical examination revealeda pale, wasted, tachypneic infant with chest retractions.Auscultation revealed a positive S4 and a grade 3/6 holo­systolic murmur of mitral regurgitation at the apex radiatingto the axilla and left back.

A thallium scan also was performed. Static images showeda large defect involving the anterolateral wall and extending

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Figure 2. A, Aortogram showing single right coronary artery(arrow). B, Later phase of the same aortogram, showing theretrograde filling into the right pulmonary artery. The arrow pointsto the region of the pulmonary trunk. N = narrowing at the junctionof the left subclavian artery with the descending aorta, suggestingcoarctation of the aorta.

to the inferior wall. The delayed images suggested that theanterolateral wall was ischemic rather than infarcted. Ele­vated creatine kinase (CK) levels also suggested myocardialinfarction, (CK 716 U/liter, CK2-MB fraction 15%).

Surgery. Because of the worsening clinical condition,it was decided to ligate the anomalous coronary artery or,possibly, disconnect it and anastomose it to the left subcla­vian artery. Correction of the coarctation of the aorta wasalso considered. The infant was operated on and the anom­alous left coronary artery from the right pulmonary arterywas ligated. There was immediate improvement on the elec­trocardiogram. The ST-T segments descended, although theydid not become normal. Ligation rather than implantationwas chosen because the left coronary artery was consideredto be small. The aortic isthmus was also inspected and itwas decided not to proceed with the resection because visualinspection did not suggest marked narrowing.

The infant did well immediately after the surgery. Thenext day, however, he had an episode of supraventriculartachycardia and hypotension. With digoxin and cardiover-

Figure 1. Present case. Nine lead electrocardiogram showing deepand wide Q waves in leads II, III and aVF, Vs and V6• MarkedST elevation is seen in leads Vs and V6.

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sion, he returned to normal sinus rhythm. A little later thatday, he developed tachycardia with atrial flutter. An echo­cardiogram showed nonmoving anterior and posterior leftventricular walls. The same evening (I day after surgery)he became hypotensive, went into cardiac arrest and couldnot be resuscitated.

Pathologic examination. Aside from the findings in theheart, the pathologic diagnosis was: I) pulmonary edema,atelectasis and hemorrhage, 2) fatty infiltration of the liver,and 3) submucosal edema and hemorrhage in the bladder.

Heart. The heart was greatly enlarged, weighing 93.5 gin the fixed state. The apex was formed by the left ventricle.The right atrium and right ventricle were hypertrophied andenlarged. The tricuspid and pulmonary valves were normal.The left coronary artery emerged at the base of the originof the right pulmonary artery (Fig. 3). The left coronaryartery proceeded around the left side of the posterior aspectof the base of the pulmonary trunk (Fig. 4) and divided intothree branches-the anterior descending, the ramus obtusi(oblique) and the left circumflex. The left circumflex branchformed the posterior descending branch. The main left coro­nary artery was ligated surgically at its base. The rightcoronary artery emerged from the right aortic sinus of Val­salva. After giving off the ramus acuti, it gave rise to severalterminal small branches to the posterior wall of the rightventricle. The ductus arteriosus was probe-patent.

The left atrium was hypertrophied and enlarged and showeddistinct diffuse fibroelastosis. Although the mitral orificewas normal in size, the posterior leaflet was poorly devel­oped. The chordae tendineae were abbreviated, and the an­terior and posterior papillary muscles were fibrosed andsituated more proximally than normal (Fig. 5). The leftventricle was enlarged, and its wall was thinner than normal,especially in the anterior wall (Fig. 5). The ventricular sep­tum was intact. The endocardium revealed fibroelastosisthroughout the septum and free walls and the myocardiumshowed areas of fibrosis grossly (Fig. 5). The aortic orificewas smaller than normal, but its valve was normally formed.The transverse aorta revealed distinct narrowing with aprominent circumferential ridge at the junction of the sub­clavian artery and the descending aorta. The descendingaorta was outpouched at the junction of the ductus arteriosus.Histologically, the sections of the left ventricle showed oldand recent inferolateral and anterior myocardial infarction.

DiscussionReported cases. When the left coronary artery arises

from the pulmonary artery. it is usually from the main pul­monary trunk. The three reported cases (1-3) in which theleft coronary artery originated from the right pulmonaryartery were described as follows.

Figure 3. Origin of the left coronary artery from the right pul­monary artery. Arrow points to the mouth of the left coronaryartery. LP = left pulmonary artery; PY = pulmonary valve.

Case J. In the first reported case (I), a 3 '12 week oldinfant with tetralogy of Fallot had origin of the left coronaryartery from the right pulmonary artery, just after the originof the latter vessel. The left coronary artery gave off the

Figure 4. External view of the left coronary artery as it passesalong the posterior aspect of the base of the pulmonary trunk (PT).Note the probe lifting the left coronary artery as the vessel passesalong this aspect. AD = left anterior descending coronary artery;LC = left circumflex coronary artery; LY = left ventricle.

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Figure 5. The open left ventricle (LV) revealingthe fibrosis in the anterolateral and inferior wallsand the septum, Also note the fibrosed anterior (APM)and posterior (PPM) papillary muscles situated moreproximally than normal, Arrows point to the fi­brosed areas in the anterolateral and inferior walls,A = aorta,

anterior descending artery "which gave off a large inter­ventricular branch. This branch ramified over its usual dis­tribution as well as the apical region, extending to aboutone-third of the way along the inferior interventricular groove,The remainder of the left coronary artery appeared to ramifyover its normal distribution" (I).

Case 2. In the second case (2), a 3 year old girl had aventricular septal defect and pulmonary hypertension. Theleft coronary artery arose from the right pulmonary artery,I cm distal to the bifurcation of the pulmonary trunk. Thiswas diagnosed postmortem after the surgical closure of theventricular septal defect.

Case 3. In the third case (3), a 3 week old infant hadpersistent congestive heart failure and failure to thrive. Car­diac catheterization revealed the complete form of atrio­ventricular canal, mild sub- and supravalvular aortic ste­nosis, patent ductus arteriosus, coarctation of the aorta withmarked hypoplasia of the isthmus and anomalous origin ofthe left main coronary artery from the inferior aspect of theproximal right pulmonary artery. The right coronary arteryarose from the ascending aorta. The child was managedmedically.

Present case. Our case is the first of anomalous originof the left pulmonary artery from the right pulmonary arteryin association with intact ventricular septum and coarctationof the aorta. The marked fibrosis of the left ventricle maybe related to the poor collateral circulation. In addition,because the coarctation of the aorta was not corrected at thetime of ligation of the left coronary artery, this could haveaffected the left ventricular contractility postoperatively, es­pecially because the left coronary artery was the dominantvessel. The recently and previously infarcted left ventricleprobably was unable to function adequately in the presenceof coarctation.

The electrocardiographic or thallium scan findings are ofinterest in the four cases of origin of the left coronary arteryfrom the right pulmonary artery. In our case, the electro­cardiogram was somewhat atypical for anomalous left coro­nary artery, because it showed the infarct pattern best in theinferior wall. The thallium scan also suggested that theinfarct was in the inferior wall and that the lateral wall wasischemic.

In the first reported case (I) the electrocardiogram didnot reveal any characteristics of ischemia. Likewise, in thesecond reported case (2), the electrocardiogram did not showany infarction pattern. Pulmonary hypertension may havepreserved the coronary perfusion in that case. In contrast,Driscoll et al. (3) showed discordance of the QRS complexand T waves in the left lateral precordial leads, suggestingmyocardial ischemia. Thus, evidence of ischemia may notbe present, especially if there is a left to right shunt andpulmonary hypertension.

Surgical management. In some selected cases, it maybe possible to take the left coronary artery from the rightpulmonary artery and anastomose it to the aorta. Becausethe main left coronary artery segment is long in these cases,the anastomosis may prove easier than in cases where themain left segment is short (as in origin of the coronary arteryfrom the main pulmonary trunk). However, when a con­genital lesion is associated with origin of the left coronaryartery from the right pulmonary artery, producing pulmo­nary hypertension, removal of the congenital lesion willlower the pulmonary pressure and lessen the flow into theleft coronary artery, complicating the surgical outcome, asin the case of Rao et al. (2). If complete repair is attempted,it might be better, if surgically feasible, to transfer the leftcoronary artery before repairing the tetralogy of Fallot orventricular septal defect.

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ReferencesI. Masel L. Tetralogy of Fallot with origin of the left coronary artery from

the right pulmonary artery. Med J Aust 1960; 1:213~7.

2. Rao BNS, Lucas RV Jr, Edwards JE. Anomalous origin of the leftcoronary artery from the right pulmonary artery associated with ven­tricular septal defect. Chest 1970;58:616-20.

3. Driscoll OJ. Garson A Jr, McNamara OG. Anomalous origin of theleft coronary artery from the right pulmonary artery associated withcomplex congenital heart disease. Cathet Cardiovasc Oiagn 1982;8:55-61.

4. Nora 11, McNamara OG. Anomalies of the coronary arteries and coro­nary artery fistula. In: Watson H, ed. Pediatric Cardiology vol. 17.London: Lloyd-Luke, 1968:297.