Pulmonary Arteriovenous Fistula Discovered After Percutaneous Patent Foramen Ovale Closure in a 27-Year-Old Woman

Patent foramen ovale (PFO) is a common condition with an incidence as high as 25% in the general population.1 In some studies, young patients who present with neurological events show a higher prevalence of PFO and an association with a significant increase in recurrent events.2–4 Over the last few years, there has been a great deal of interest in the percutaneous management of PFO. Recent studies have demonstrated that percutaneous closure is both safe and successful in the treatment of PFO, as well as other intracardiac communications.5–10 Sporadic pulmonary arteriovenous malformation (PAVM) is uncommon in the general population. In the majority of cases, PAVM is associated with hereditary hemorrhagic telangiectasia (HHT), an autosomal dominant disorder that occurs with an incidence as high as 1 in 2,351 in some populations.11,12 Neurologic symptoms, a common presentation in patients with HHT, are usually attributable to emboli from these malformations.13 We present a patient with both PFO and PAVM who was treated with percutaneous closure of PFO. Only after closure was performed was the diagnosis of PAVM (presumably due to HHT) made. Case Report. A 27-year-old woman with a previous history of myoclonic epilepsy and migraine (treated with Depakote), presented with a history of a transient ischemic attack. She had experienced a visual field deficit lasting 3 minutes, as well as a period of aphasia and confusion lasting 20 minutes. The patient underwent an extensive evaluation including magnetic resonance imaging and MRA of the brain, intracranial and extracranial Doppler, and carotid studies; all were normal. Surface echocardiography indicated a “large” PFO with early right-to-left shunting during bubble study. The patient was referred for percutaneous closure of her PFO. As part of her preoperative evaluation, a hypercoagulable work-up was performed; it was negative. Transesophageal echocardiography confirmed the presence of early right-to-left shunting, demonstrated by Doppler flow and early crossing of bubbles from the right to the left atrium (Figure 1). Percutaneous closure of the PFO was accomplished with a 23 mm Cardioseal device (NMT Medical, Inc.) deployed through a 9 French femoral venous approach. There were no complications during this procedure. Transesophageal echocardiography, performed concurrently during the placement of the device, demonstrated excellent apposition to the inter-atrial septum. Immediately after device placement, a repeat bubble study demonstrated an absence of early shunting. However, after approximately 3 cardiac cycles, there was a large influx of bubbles into the left atrium indicating continued right-to-left shunting and suggestive of the diagnosis of pulmonary arteriovenous malformation (Figure 2). A computed tomography angiogram demonstrated a large arteriovenous fistula in the patient’s right lung (Figures 3 and 4). Selective pulmonary angiography revealed a 4.8 mm arteriovenous malformation in the right lower lobe, which was embolized by interventional radiology using three 5 mm x 8 cm 0.035" platinum coils (Cook Corporation, Bloomington, Indiana) (Figure 5). Contralateral pulmonary angiography was negative for arteriovenous malformations. Upon later reflection, the patient recalled that her father had suffered a cerebral hemorrhage. The patient did not know the details concerning the stroke, but recalled it had been attributed to a “blood vessel problem”. In an interview with the patient’s father, subtle peri-oral telangiectasias were noted. This physical finding, combined with his clinical history, suggested a diagnosis of HHT. Discussion. Percutaneous closure of a PFO is a procedure that is increasing in popularity in the adult cardiology population. In selected patients, it is an attractive alternative to surgery for elimination of significant shunts, and reduction of neurologic events due to paradoxical emboli. Echocardiography is a key test in choosing patients for PFO closure. An intravenous bubble study during either surface or transesophageal echocardiography can demonstrate right-to-left shunting. It is sometimes difficult, however, to differentiate right-to-left shunting due to an inter-atrial communication from shunts at other levels. In 1 report, patients were misdiagnosed with PFO at the time of surface echocardiography. Right-to-left shunting was demonstrated based on the early appearance of bubbles in the left atrium. However, transesophageal echocardiography performed at the time of percutaneous PFO closure failed to show inter-atrial communication. HHT and pulmonary arteriovenous malformation was diagnosed.14 Patients with HHT may have vascular malformations in a wide variety of organ systems. Neurologic complications have been associated with both cerebral and pulmonary arteriovenous malformations. The prevalence of PAVM in patients with HHT has been reported to be as high as 24%.15 In some series, over half of the patients with PAVM had an initial presentation of a CNS event such as transischemic attack, stroke or cerebral abscess.16 Currently, it is recommended that fistulas larger than 3 mm in diameter be closed. Nonsurgical closure of pulmonary arteriovenous malformations may be achieved by balloon or coil embolization.17 After closure of a large PAVM, echocardiography may still demonstrate right-to-left shunting during bubble study. This is usually due to small shunts within the lung parenchyma, which allow bubbles to cross, yet are not angiographically apparent.18 In this case, it remains unclear whether the PFO or the PAVM was the cause of her neurologic event. She had no chest radiographs prior to her echocardiogram, so the diagnosis of PAVM was not entertained prior to her presentation for PFO closure. However, knowledge of her PAVM prior to her PFO closure would probably not have substantially changed her therapy. It is likely that she would still have ultimately had both conditions addressed. At the time of this report, she has been free of new neurologic events for 6 months. To our knowledge, this is the first report of a patient presenting with PFO and occult PAVM. With the increased interest in percutaneous closure of PFO in adults, this case illustrates the need for detailed physical exam, family history and an appropriate clinical suspicion of HHT when undertaking PFO closure.

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