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Tex Heart Inst J. 2001; 28(2): 122–124.
PMCID: PMC101151

Right Pulmonary Artery-to-Left Atrium Communication

A Rare Cause of Systemic Cyanosis

Abstract

Direct communication between the right pulmonary artery and the left atrium is a rare congenital vascular malformation. The clinical diagnosis is difficult, and preoperative angiography is essential. We treated this anomaly successfully with surgery and the use of cardiopulmonary bypass in an 11-year-old boy. Surgery provides a complete cure for this anomaly.

Key words: Cyanosis/etiology, fistula/diagnosis/surgery, heart atrium/abnormalities, pulmonary artery/abnormalities

Direct communication between the right pulmonary artery and the left atrium is a very rare congenital vascular malformation. We present a case involving this anomaly and details of the successful surgical repair.

Case Report

An 11-year-old boy was admitted to our institution on 15 May 1998 for decreased exercise tolerance and mild cyanosis. Mild heart failure had been diagnosed immediately after birth. At 6 years of age, the boy had developed increasing cyanosis and dyspnea on exertion. He began experiencing recurrent pulmonary infections at the age of 10.

Clinical Examination.

The patient showed systemic cyanosis with clubbing of the fingers. The transcutaneous arterial oxygen saturation was 80%. On auscultation, a faint systolic murmur was heard at 2nd intercostal space on the left sternal border, and a split-second heart sound was audible. Electrocardiography showed normal sinus rhythm with a heart rate of 95 beats/min and incomplete right bundle-branch block. All laboratory findings were within normal limits.

Chest radiography revealed an enlarged right atrial silhouette and normal pulmonary vasculature. Echocardiography showed massive enlargement of the right ventricle and of both atria, and a central atrial septal defect (diameter, 15 mm) with a continuous left-to-right shunt. Venous contrast echocardiography revealed multiple echoes in the left atrium that confirmed the right-to-left shunt. No other intracardiac anomalies were detected.

Cardiac catheterization data are presented in Table I. The Qp:Qs was 0.6:1. Angiography revealed a dilated right pulmonary artery with increased pulsation; a large fistula with a diameter of 12 mm between the right pulmonary artery and the enlarged left atrium; and an atrial septal defect (Fig. 1).

figure 7FF1
Fig. 1 Angiography in the frontal projection with the catheter tip in the saccular cavity (SC) of the left atrium (LA), showing a fistula (F) between the right pulmonary artery (RPA) and an enlarged left atrium with a saccular cavity. Contrast medium ...
Table thumbnail
TABLE I. Cardiac Catheterization Data

Surgical Technique.

Surgery was performed through a median sternotomy with normothermic cardiopulmonary bypass and crystalloid cardioplegic solution. The dilated right pulmonary artery was dissected, but the anomalous vessel was difficult to identify. Therefore, the right atrium was opened and, through the atrial septal defect, the orifice of the anomalous vessel was found just posterior to the defect, between the right and left pulmonary veins. A probe was passed through the anomalous vessel into the right pulmonary artery. The origin of the vessel was in the posterior wall of the right pulmonary artery just proximal to the lower lobe branch. The anomalous vessel was doubly ligated and the atrial septal defect was closed by direct suture.

Results.

The arterial oxygen partial pressure increased from 70 mmHg before cardiopulmonary bypass (CPB) to 360 mmHg immediately after CPB (the fractional inspiratory oxygen [FiO2] was 0.5). Intraoperative transesophageal contrast echocardiography was performed by direct injection of contrast medium into the left atrium, the right atrium, and the right pulmonary artery; no residual shunts were seen.

The boy's postoperative course was uneventful, and he was discharged from the hospital on the 10th postoperative day. When we last saw this patient, nearly 3 years after surgery, his condition was normal.

Discussion

Direct communication between the pulmonary artery and the left atrium is a rare anomaly. Since the 1st description by Friedlich and co-authors in 1950, 1 only 54 cases have been reported. 2–4 The age of the oldest reported patient was 45 years. 2 Some authors consider the anomaly as a variant of a pulmonary arteriovenous (AV) fistula; 5 however, unlike pulmonary AV fistulas, pulmonary-to-left atrium fistulas do not involve direct communication between an artery and a vein. In most of the reported cases, the anomalous vessel originates from the posterior wall of the right pulmonary artery and is connected to the left atrium between the right and left pulmonary veins. Associated atrial septal defects are common. Other concomitant cardiac malformations are rare, but anomalies of the right lung, such as absence of the lower or middle lobe, right lung sequestration, and diverticulum of the right main bronchus, have been reported. 5–7 Cyanosis resulting from the right-to-left shunt is usually not evident until adolescence or adulthood. In newborns, however, large shunts can cause severe heart failure necessitating emergency surgical intervention. 3

Diagnosis of this anomaly is difficult. After contrast medium is injected into peripheral veins in the absence of high pulmonary vascular resistance, echocardiography reveals contrast in the left atrium, which suggests direct communication with the venous circulation. Communication between the right pulmonary artery and the left atrium should be considered as part of the differential diagnosis when such conditions as these are found: a left superior vena cava that drains into the left atrium, an unroofed coronary sinus, or an atrial septal defect with elevated right atrial pressure and a right-to-left shunt. In the presented case, echocardiographic evaluation showed a right-to-left shunt, an atrial left-to-right shunt, and no sign of elevated pulmonary pressure; however, there was no direct evidence of the fistula. Cardiac catheterization with selective angiography of the right pulmonary artery was necessary to confirm this unusual diagnosis. With regard to treatment, we ruled out transcatheter closure of the anomalous vessel with an umbrella device because of the possibility of obstruction of the pulmonary veins.

Elective surgery is the best treatment to prevent chronic arterial hypoxemia, systemic thromboembolic complications, congestive heart failure, and shunt-derived pulmonary hypertension. Severe heart failure in newborns must be treated as a surgical emergency. However, newborns who have mild cyanosis and no apparent heart failure tend to respond well to medical treatment; therefore, surgery can be postponed. 8 In view of the 22% mortality rate that occurred as a result of bleeding or other complications among the 51 patients reviewed by Zeebregts and colleagues and reported in 1997, 2 it appears that surgery for this anomaly carries considerable risk and should be approached with due caution.

In conclusion, the clinical diagnosis of right pulmonary artery-to-left atrium communication is difficult, and angiographic investigation is mandatory. Surgery provides a complete cure and should be performed with the patient on cardiopulmonary bypass.

Acknowledgments

We are grateful for the editorial assistance of Tonie Derwent and Diana Kendall. We are indebted to Annette Gaußmann, who provided the angiogram.

Footnotes

Address for reprints: Vladimir Alexi-Meskishvili, MD, PhD, Deutsches Herzzentrum Berlin, Augustenburger Platz 1, 13353 Berlin, Germany

References

1. Friedlich A, Bing RJ, Blount SG Jr. Physiological studies in congenital heart disease. IX. Circulatory dynamics in the anomalies of venous return to the heart including pulmonary arteriovenous fistula. Bull Johns Hopkins Hosp 1950;86:20–57. [PubMed]
2. Zeebregts CJ, Nijveld A, Lam J, van Oort AM, Lacquet LK. Surgical treatment of a fistula between the right pulmonary artery and the left atrium: presentation of two cases and review of literature. Eur J Cardiothorac Surg 1997;11:1056–61. [PubMed]
3. Saatvedt K, Stake G, Lindberg H. Fistula between the right pulmonary artery and the left atrium—an unusual cause of cyanotic heart disease. Cardiol Young 1995;5:85–7.
4. Mohanty SR, Yadav R, Kothari SS, Airan B. Right pulmonary artery left atrium communication. Ann Thorac Surg 2000;69:279–71. [PubMed]
5. Lucas RV Jr, Lund GW, Edwards JE. Direct communication of a pulmonary artery with the left atrium. An unusual variant of pulmonary arteriovenous fistula. Circulation 1961;24:1409–14. [PubMed]
6. Kroeker EJ, Adams D, Leon AS, Pouget JM. Congenital communication between a pulmonary artery and the left atrium: physiologic observations and review of the literature. Am J Med 1963;34:721–5. [PubMed]
7. Abe T, Kuribayashi R, Sato M, Nieda S. Direct communication of the right pulmonary artery with the left atrium. A case report and a review of the literature. J Thorac Cardiovasc Surg 1972;64:38–44. [PubMed]
8. Cheatham JP, Barnhart DA, Gutgesell HP. Right pulmonary artery to left atrium communication. An unusual cause of cyanosis in the newborn. Pediatr Cardiol 1982;2: 149–52. [PubMed]

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