Rare case of pulmonary arteriovenous fistula simulating residual defect after transcatheter closure of patent foramen ovale for recurrent paradoxical embolism

Neurological and cardiopulmonary manifestations of pulmonary arteriovenous malformations

Pulmonary arteriovenous malformations (PAVMs) are direct pulmonary artery-to-vein connections without pulmonary capillaries that result in intrapulmonary right-to-left blood shunts. Although most patients with PAVMs may be entirely asymptomatic, PAVMs can induce a series of complications involving the neurological, cardiovascular, and respiratory systems that can lead to catastrophic and often fatal clinical sequelae. In this study we review the available literature and summarize the reported PAVM-related complications among patients with PAVMs. The reviewed studies included observational studies, case studies, prospective studies, and cohort studies, and we provide an overview of PAVM-related neurological and cardiopulmonary manifestations, including stroke, cerebral abscess, transient ischemic attack, cerebral hemorrhage, migraine, seizure, dizziness, cardiac failure, arrhythmia, myocardial infarction, cough, hypoxemia, dyspnea, respiratory failure, hemoptysis, and hemothorax. Identifying and treating PAVMs before the presentation of major complication is important because this can prevent the occurrence of complications and can result in better outcomes. PAVM patients should thus be better evaluated and managed by a multidisciplinary team because they may be in a treatable phase prior to their condition becoming life-threatening.

Heart-brain axis: Association of congenital heart abnormality and brain diseases

Brain diseases are a major burden on human health worldwide, and little is known about how most brain diseases develop. It is believed that cardiovascular diseases can affect the function of the brain, and many brain diseases are associated with heart dysfunction, which is called the heart-brain axis. Congenital heart abnormalities with anomalous hemodynamics are common treatable cardiovascular diseases. With the development of cardiovascular surgeries and interventions, the long-term survival of patients with congenital heart abnormalities continues to improve. However, physicians have reported that patients with congenital heart abnormalities have an increased risk of brain diseases in adulthood. To understand the complex association between congenital heart abnormalities and brain diseases, the paper reviews relevant clinical literature. Studies have shown that congenital heart abnormalities are associated with most brain diseases, including stroke, migraine, dementia, infection of the central nervous system, epilepsy, white matter lesions, and affective disorders. However, whether surgeries or other interventions could benefit patients with congenital heart abnormalities and brain diseases remains unclear because of limited evidence.

Wide-ranging clinical spectrum of paradoxical embolism

The purpose of this review is to raise the index of suspicion for paradoxical embolism among generalists. The review is based solely on anecdotal reports compiled from EMBASE, MEDLINE, Googlescholar and Pubmed. Search terms were 'paradoxical embolism', 'pulmonary embolism' and 'pulmonary arteriovenous malformations'. What emerged was that right-to-left paradoxical embolism could occur with or without concurrent pulmonary embolism, and also with and without proof of the presence of an 'embolus-in-transit'. Potential sites of single or multiple systemic involvement included the central nervous system, the coronary circulation, renal arterial circulation, splenic circulation, the mesenteric circulation and the limbs. In many cases, the deep veins of the lower limbs were the source of thromboembolism. In other cases, thrombi originated from an atrial septal aneurysm, from a central venous line, from a haemodialysis-related arterio-venous shunt, from a popliteal vein aneurysm, internal jugular vein, superior vena cava, from a pulmonary arteriovenous malformation, from tricuspid valve endocarditis (with and without pulmonary embolism) and from the right atrium, respectively. Stroke was by far the commonest systemic manifestation of paradoxical embolism. Some strokes were attributable to pulmonary arteriovenous malformations with or without coexistence of intracardiac shunts. Clinicians should have a high index of suspicion for paradoxical embolism because of its time-sensitive dimension when it occurs in the context of involvement of the intracranial circulation, coronary circulation, mesenteric circulation, and peripheral limb circulation.

Stroke in a patient with pulmonary arteriovenous fistula: A case report study

Pulmonary arteriovenous fistula (PAVF) is a venous malformation that permits right to left shunting of blood, bypassing the pulmonary capillary bed. Often PAVFs are seen in association with hereditary conditions. On the other hand, isolated PAVFs are rare and asymptomatic. There have been few reports of isolated PAVF related complications. A patient was referred to us with dysarthria and diplopia and history of surgically-treated PAVF. Further evaluations revealed a stroke in thalamic region. We found an open PAVF in a case of thalamic stroke.

Sometimes they come back: recurrent noncardiac right-to-left shunt after percutaneous patent foramen ovale closure

: An increasing number of patients are being evaluated for percutaneous patent foramen ovale (PFO) closure to prevent recurrent cerebrovascular events, but debate still exists on therapeutic indications and off-label closure device implantation. Pulmonary arteriovenous fistulas (PAVFs) are a rare and heterogeneous malformation prevalently associated with Rendu-Osler-Weber syndrome, and may mimic PFO right-to-left shunt (RLS), leading to unnecessary interventions and in some cases to relapses. Residual shunt is increasingly being observed both after PFO closure and PAVF embolization, even at long-term follow-up, with unclear clinical relevance. This instrumental and possibly therapeutic failure could lie in the presence of pulmonary microfistulas, either pre-existing or following the intervention. Hence, if RLS persists after optimal device placement and reasonable endothelialization time, the presence of a PAVF should be assumed and investigated; if RLS recurs after previous, negative echocontrast studies, presence of device-related complications or pulmonary microfistulas should be taken into consideration.

Common carotid artery duplex for the bubble test to detect right-to-left shunt

We prospectively compared the bubble test with agitated saline for right-to-left shunt using transcranial Doppler (TCD) of the right middle cerebral artery and second harmonic imaging duplex of the right common carotid artery (CCA) in 100 consecutive patients. Microembolic signals (MES) were counted offline. MES were classified into 6 classes: absent (class 0), 1-10 MES (class 1), 11-20 MES (class 2), 21-30 MES (class 3), 31-50 MES (class 4) and >50 MES or "curtain effect" (class 5). For TCD, classes 2-5 combined (i.e., "large" shunts), the sensitivity of duplex with the Valsalva maneuver was 95.3%, the specificity was 100%, the positive predictive 100%, the negative predictive value 96.6% and accuracy 98.0%. Second harmonic imaging duplex of the CCA may substitute TCD for the bubble test when an adequate cranial bone window is not available. This technique may also greatly increase the number of facilities where the bubble test can be carried out. However, tests with few or no MES need to be confirmed by TCD or transesophageal echocardiography.

Right-to-left shunt, atrial septal aneurysm and thrombophilia in patients with cryptogenic stroke or TIA vs. those with venous thrombo-embolism

Whether intracardiac right-to-left shunt (RLS) is an independent risk factor for cerebrovascular accidents is disputed. In patients with RLS, venous thrombo-embolism (VTE) may predispose to paradoxical embolic events, among which stroke and transient ischemic attack (TIA). Whether genetic or acquired thrombophilia is associated with RLS is unclear. Thus, we compared prevalences of intra- and extracardiac intrapulmonary RLS and of atrial septal aneurysm (ASA) between 29 nondiabetic patients with cryptogenic stroke (n=17) or TIA (n=12) and 19 patients with VTE but without history of stroke/TIA, or autoimmune systemic disease or migraine. Carotid atherosclerosis was excluded in all patients. RLS and ASA were also evaluated in 30 healthy volunteers. We found that intracardiac RLS (31%) and ASA (21%) were detected in stroke/TIA patients and not in our selected VTE patients (both p<0.05); however, those prevalences were comparable to those detected in our controls (20% intracardiac RLS, 7% ASA, respectively, both p=NS). Within patients, thrombophilia was not associated with intracardiac RLS, but tended to be associated with ASA (83% in those with vs. 43% in those without ASA, p=0.08). In conclusions, intracardiac RLS may have a role in selected populations in the frame the multi-factorial pathogenesis of stroke/TIA of embolic origin. ASA appears to be an independent risk factor for stroke/TIA with possible interaction with thrombophilia.

A case of platypnea-orthodeoxia syndrome in a patient with a pulmonary arteriovenous fistula and a patent foramen ovale

We describe a case of a rare clinical disorder, platypnea-orthodeoxia syndrome. A 57-year-old man was admitted with progressive dyspnea. While breathing room air, arterial oxygen saturation decreased from 92% in a recumbent position to 83% in an upright position. Transthoracic echocardiography revealed normal left and right ventricular function, but intravenous infusion of air-blood-saline resulted in the appearance of microbubbles in the left side of the heart, indicating the presence of right-to-left shunt. Transesophageal echocardiography demonstrated a small amount of right-to-left shunting through a patent foramen ovale. Further, the left lower pulmonary vein was dilated, and contrast echocardiography revealed drainage of microbubbles mainly from the left lower pulmonary vein. A pulmonary angiogram revealed the presence of a pulmonary arteriovenous fistula. The patient underwent embolization of the arteriovenous fistula with subsequent resolution of dyspnea and hypoxemia. Platypnea-orthodeoxia syndrome is rare, and patients with this syndrome require an extensive workup to determine its cause.

Postoperative pulmonary arteriovenous fistula resulting in recurrent cryptogenic stroke

We report on a 66-year-old patient with a history of two cryptogenic strokes and a patent foramen ovale (PFO) who received a transcatheter closure of his PFO in our institution, but shortly after the intervention there was still a relevant right-to-left shunt. The following work-up showed an isolated pulmonary arteriovenous fistula as the real cause for the right-to-left shunt and hence the two strokes.