Anomalous origin of the left coronary artery from thepulmonary artery: Scintigraphic diagnosis with Tc 99mlung scan

Joong H. Choh, M.D., V. Srinivasan, M.D., Leon Levinsky, M.D.,Daniel R. Pieroni, M.D., Robert L. Gingell, M.D.,and S. Subramanian, M.D.

A case of anomalous origin of the left coronary artery from thepulmonary artery is reported. The diagnosis was made on the basis ofcharacteristic Tc 99m lung scan findings and was confirmed by subse-quent angiocardiography and surgery.

Case Report

A 9-week-old girl was referred to the Children's Hospital of Buff'alobecause of a severe breathing problem. Her growth and developmenthad been normal until the age of 6 weeks, wvhen her parents notedrespiratory difficulty and occasional substernal retraction. She wastreated for an upper respiratory infection for 3 weeks without improve-ment. At the age of 9 weeks, her clinical status deteriorated to includecyanosis, marked irritability, and respiratory distress. Upon arrival at thehospital, her respiratory rate was 80/min. Physical examination showed

From the Departments of Cardiology and Cardiovascular Surgery, Children'sHospital, Buffalo, New York.

Address for reprints: S. Subramanian, M.D., Chief, Division of CardiovascularSurgery, and Professor of Surgery, State Uniiversity of New York at Buffalo, 219Bryant Street, Buffalo, New York 14222.

Cardiovascular Diseases, Bulletin of the Texas Heart InstituteVolume 7 Number 4 December 1980

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tachycardia of 200/B/min, a ventricular gallop rhythm, and markedhepatomegaly, 6 cm below the right subcostal margin. Electrocardio-graphy revealed a large Q wave in leads AVL, V5, and V6 (Fig. 1). Thechest roentgenogram showed marked cardiomegalv with increased pul-monary vascularity (Fig. 2).The patient was digitalized and treated with intravenous furosemide.

On the basis of' EKG f'indings, a diagnosis of' anomalous left coronaryartery was considered, and a lung scan was performed with intravenousinjection of Tc 99m macroaggregated serum albumin, which showed aheavy concentration of the isotope in the left myocardium (Fig. 3).Emergency cardiac catheterization and angiocardiographv demon-

strated anomalous origin of the left coronary artery from the pulmo-nary artery, retrograde f'illing of the left coronary from the rightcoronary artery (Figs. 4 and 5), severe left ventricular dysfunction(LVEDP = 20 mm Hg) and slight nmitral regurgitation. The meanpulmonary artery pressure was 30 mm Hg, and the mean systemicarterial pressure was 50 mm Hg. Emergency surgery confirmed thediagnosis. The left coronary artery originated from the posterior aspectof' the main pulmonary artery. The left ventricle was markedly dilatedand exhibited poor contractility. With the patient undergoing deephypothermia and circulatory arrest, the left coronary artery was de-tached from the pulmonary artery, along with a cuff of the parentvessel. The left subclavian artery was dissected and divided at the apexof the left chest. The distal end of the left subclavian artery was

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Fig. 2 Chest roentgenogram revealing marked cardiomegaly and pulmonary congestion.

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Fig. 4 Filling of the large right coronary artery, as shown by aortic root injection (lateral).

anastomosed to the detached left coronary artery in end-to-end fashion.Unfortunately, the patient could not be weaned from cardiopulmonarybypass because of severe low cardiac output, and she expired on theoperating table.

Discussion

Anomalous origin of the left coronary artery from the pulmonaryartery is an uncommon congenital cardiac anomaly with an incidence of0.26% to 0.46% 1,2 among all congenital heart defects. Because of earlymyocardial infarction and severe heart failure, the prognosis is poor. Amortality of 80% to 85% during infancy has been reported. 1,2 Successfulsurgical management of this anomaly has been discussed in the currentliterature,3-6 but it is crucial to detect these infants before they developirreversible myocardial damage.

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coronary system, which empties into the pulmonary artery.

Sfakianakis and colleagues7 have described the characteristic lungscan, which shows localized isotope uptake by the left ventricularmyocardium in addition to visualization of both lungs. Our experienceconfirms these findings and suggests that the relatively noninvasivetechnique of Tc 99m lung scanning provides an important diagnostictool even before cardiac catheterization. Note that in cases of atrial orventricular right to left shunting, the myocardium is visualized, alongwith the kidneys, brain, and liver; in patients with this anomaly, how-ever, the latter organs do not show any uptake.

In our patient, cardiac catheterization showed retrograde filling of theleft coronary artery from the right coronary artery despite the lungscan findings, which suggested blood flow from the pulmonary artery tothe left coronary artery. This discrepancy is probably due to bidirec-tional flow in the coronary system or incomplete development of

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collateral circulation.8 Nadas and co-workers9 describe three phases ofcoronary arterial blood flow in the anomalous coronary artery: (1) Thefirst phase, which is seen in the newborn infant, is one of antegrade flowfrom a high-pressure pulmonary artery. (2) The second phase istransitional-it occurs before complete collateralization, when bloodflow in the anomalous left coronary artery may be bidirectional. (3) Thethird phase occurs after collaterals have developed from branches of theright coronary artery; this phase exhibits retrograde flow that drainsinto a low-pressure pulmonary artery. In our patient, the blood flow wasundergoing the transitional second phase, when the myocardium wasespecially at risk.On the basis of our experience, we suggest that lung scanning may be

a useful initial noninvasive diagnostic procedure in infants with electro-cardiographic findings of myocardial ischemia and other evidence of ananomalous left coronary artery.

References

1. Wesselhoeft H, Fawcett JS, Johnson AL: Anomalous origin of the leftcoronary artery from the pulmonary trunk: Its clinical spectrum, pathology,pathophysiology, based on a review of 140 cases with seven further cases.Circulation 38:403, 1968

2. Askenazi J, Nadas AS: Anomalous left coronary artery originating from thepulmonary artery: A report of 15 cases. Circulation 51:976, 1975

3. Grace RR, Angelini P, Coolev DA: Aortic implantation of anomalous leftcoronary artery arising from the pulmonary artery. Am J Cardiol 39:608,1977

4. Suzuki Y, Horiuchi T, Ishizawa E Jr, Sato T, Fukuda M, Kakihata H:Subclavian-coronary arterv anastomosis in infants for the Bland-White-Garland syndrome: A two-year angiographic follow-up. Ann Thorac Surg25:377, 1978

5. Neches WH, Mathews RA, Park S, Lexon CC, Zuberbuhler JR, Siewers R,Bahnson HT: Anomalous origin of the left coronary artery f'rom thepulmonary artery. Circulation 50:582, 1974

6. Venugopal P, Subramanian S: Anomalous origin of the left coronary arteryfrom the pulmonary artery. Ann Thorac Surg 19:451, 1975

7. Sfakianakis GN, Damoulaki-Sfakianaki E, McClead RE, Craenen J: Anoma-lous origin of the left coronary arterv. Diagnosis by a lung scan. New Eng JMed 296:675, 1977

8. Edwards JE: Editorial: The direction of blood flow in coronary arteriesarising from the pulmonary trunk. Circulation 29:163, 1964

9. Nadas AS, Gamboa R, Hugenholtz PG: Anomalous left coronary arteryoriginating from the pulmonary artery. Report of two surgically treated caseswith a proposal of hemodynamic and therapeutic classification. Circulation29:167, 1964

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