Eur J Cardiothorac Surg 2001;20:1052-1053
© 2001 Elsevier Science NL
Pulmonary artery to left atrial fistula
K.M. Krishnamoorthya,
S. Raob
a Department of Cardiology, Sri Sathya Sai Institute of Higher Medical Sciences, Puttaparthi 515 134, India
b Department of Cardiac Surgery, Sri Sathya Sai Institute of Higher Medical Sciences, Puttaparthi 515 134, India
Received 5 February 2001;
received in revised form 20 June 2001;
accepted 20 June 2001.
Corresponding author. SCTIMST, Trivandrum 695 011, India. Tel.: +91-471-555532; fax: +91-471-446433
e-mail: saikm{at}sctimst.ker.nic.in
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Abstract
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A patient with type I right pulmonary artery to left atrial fistula is being presented. He had cyanosis with no precordial findings. Diagnosis was made by transoesophageal echocardiography. Simple ligation of the fistula without cardiopulmonary bypass resulted in complete cure. Early operation to prevent complications is highlighted. Transoesophageal findings of the lesion have not been reported in literature.
Key Words: Pulmonary artery to left atrial fistula • Pulmonary arteriovenous fistula • Transoesophageal echocardiography • Cyanosis
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1. Introduction
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Pulmonary artery (PA) to left atrial (LA) fistula is a rare anomaly. We report a patient who had type I PA–LA fistula diagnosed non invasively by transoesophageal echocardiography. He underwent successful surgery without cardiopulmonary bypass.
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2. Case report
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A 19 year old boy had progressive central cyanosis and clubbing from 3 years of age. Physical growth was adequate. There were no haemangiomas. Precordial examination revealed no abnormal findings. There were no murmurs over lung fields. Haemoglobin was 20 g/dl. Haematocrit was 61%. ECG showed left ventricular diastolic overload pattern. X-ray chest showed a crescentic shadow parallel to the right atrium.
Transthoracic echocardiogram showed colour flow into LA. Injection of agitated saline in the cubital vein showed the contrast filling LA, immediately after entering PA. Transoesophageal echocardiogram delineated a vessel arising from the right PA and entering LA (Fig. 1). Colour flow showed the direction of flow from right PA to LA. PA to LA fistula was diagnosed. On catheterisation, a catheter from PA entered LA through the fistula. Oxygen saturation in LA, left ventricle and aorta ranged from 65 to 70%. Right PA injection filled the fistula and then LA immediately afterwards (Fig. 2). Right PA wedge injection showed that pulmonary veins entered LA separately.
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Fig. 1. Transoesophageal echocardiogram showing drainage of right pulmonary artery (RPA) into left atrium (LA).
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Fig. 2. RPA injection in anteroposterior view showing the fistula (single arrow) opening into LA (double arrow).
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Right thoracotomy through the third intercoastal space showed a trilobed right lung. On dissecting right PA, an anomalous vessel was seen arising from its posteroinferior aspect after its right lower lobe branch. This tract (1.5 cm diameter) was traced and seen to enter LA posterolaterally, separate and superior to the opening of right lower pulmonary vein. Right PA branched normally distal to the anomalous vessel. On clamping the communication, oxygen saturation rose to 99.8% within 3 min. It was simply ligated. He was asymptomatic on follow up. Haemoglobin and haematocrit normalised.
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3. Discussion
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Pulmonary arteriovenous fistula is an abnormal communication between a pulmonary artery and vein with absence of the capillary network that links the two [1]. Embryologically, pulmonary arteriovenous fistula develops due to incomplete degeneration of the septum between the arterial and venous plexus of the pulmonary vascular bed. It may also be due to formation of thin walled sacs because of a defect in the capillary loops. A pulmonary vein connected to such a fistula is absorbed into LA during development, forming a PA–LA fistula [2]. Agenesis of a lobe of the lung and consequent absence of pulmonary capillary bed is another explanation [3]. Alternatively, it may represent the original vascular connection of an accessory lobe as seen in one patient [4].
Only about 30 cases of PA to LA fistula have been reported [2], all of them from right PA to LA. Only one case of left PA to LA fistula is known [5]. Although they have manifested from day 1 to middle age [2], most cases present in the third decade [5]. Among symptoms and signs, dyspnoea is seen present in 50%, neurological symptoms in 20% [6], telangiectasias in 33% [7], and cyanosis in 60% patients. Precordial findings are rare. Among the reported cases, only one patient had murmur (continuous murmur) [4]. ECG may be normal [2]. Surgery is required to prevent paradoxical embolism [2]. Other complications are rupture, haemopytsis, polycythaemia and brain abscess [4]. Early surgery is required to prevent these. Ligation or division of the anomalous vessel is sufficient, being simple and curative [2]. Cardiopulmonary bypass is required if dissection of the vessel is technically difficult [8], or biopsy of the vessel is performed [2].
PA–LA fistula has been categorized into 3 types [9]. A fourth type has been added subsequently [2]. In type I, right PA branches normally. But an additional fistulous channel connects right PA to LA. Pulmonary venous return is normal. In type II, the lower lobe branch of right PA drains directly into LA, forming an aneurysmal sac. This communication drains into LA in place of the absent right lower pulmonary vein. Right lung abnormalities are the rule [10]; one or more lobes may be absent. Type III is similar to type I with pulmonary veins draining into the abnormal channel that connects right PA and LA. Type IV is similar to type II with pulmonary veins entering the aneurysmal sac. Our patient had abnormal communication between right PA and LA with normal branching of right PA distal to the communication, normal pulmonary venous drainage and lung development. He had type I PA–LA fistula.
Catheterisation and angiography were considered essential for the diagnosis [2]. But we have shown that diagnosis can be made non-invasively. Our patient had a complete diagnosis after contrast injection and TEE. The case is being presented because of non invasive diagnosis and successful surgery in a rare case. Further, transoesophageal echocardiographic findings of this entity have not been reported. Cyanosis, little or no precordial findings, normal second heart sound and a shadow parallel to heart border on x-ray should make one suspect the diagnosis.
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References
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Abstract
1. Introduction
