Case report: A 44-year-old woman was admitted for surgical correction of a pulmonary arteriovenous malformation (PAVM).
This patient had a previous history of cerebral ischaemic attacks resulting in right hemiparesis and seizures. A misdiagnosis of patent foramen ovale was made and the patient was submitted to surgery. However, no patent foramen ovale was found. She was then submitted to further investigations.
As the chest X-ray demonstrated an opacity in the right lower lung field and the patient had a low arterial saturation, a PAVM was highly suspected and confirmed by computed tomography.
A pulmonary angiogram was also performed and according to the report, revealed an enlarged right pulmonary artery feeding a large fistula (aneurysmal sac 23 × 24 mm), which directly drained to the left atrium through a large anomalous communication, 18 mm in diameter. The fraction of the cardiac output that shunted from right-to-left was estimated to be 50%.
The patient underwent a right lateral thoracotomy with selective one lung ventilation. Intraoperative transoesophageal echocardiography (TOE) was used. With TOE no abnormal conduit could be found entering the left atrium. However, a large right lower pulmonary vein was seen, with turbulent flow on colour Doppler and increased flow velocity on pulsed wave Doppler.
The central localization of the PAVM made the surgical exploration difficult. The surgeon was not able to find any anomalous vessel directly connecting the fistula to the left atrium. Isolation and clamping of the feeding arteries (arising from the lower lobe branch of the right pulmonary artery) resulted in a minimal blood flow in the right lower pulmonary vein visualized by TOE. The same result was obtained with clamping of what seemed to be the efferent vessel of the PAVM.
The afferent arteries and the right lower pulmonary vein were ligated and a lower lobectomy performed.
TOE has been described as a useful tool in diagnosis of PAVM . In this case report the intraoperative use of TOE proved useful, helping the surgeon to clarify the vascular anatomy of the PAVM, namely its drainage through a pulmonary vein.
1 Chessa M, Drago M, Krantunkov P, et al. Differential diagnosis between patent foramen ovale and pulmonary arteriovenous fistula in two patients with previous cryptogenic stroke caused by presumed paradoxical embolism. J Am Soc Echocardiogr