Recurrent headache and dizziness caused by pulmonary arteriovenous fistula: transthoracic/transesophageal contrast echocardiography and CT angiography

BackgroundThe Fontan operation is a surgical procedure used in children with univentricular hearts. Pulmonary arteriovenous fistulae (PAVF) is a major complication after a Fontan operation. However, the incidence and related clinical pathophysiology of PAVF remain unclear.PurposeThis study aimed to clarify the incidence of PAVF, its clinical characteristics, and its influence on all-cause mortality.Methods and ResultsWe serially assessed the presence of PAVF using pulmonary artery angiography and/or contrast echocardiography during catheterization in 391 consecutive patients who underwent the Fontan procedure and compared the results with the Fontan pathophysiology and all-cause mortality. PAVF developed in 36 patients (9.2%), including 30 diffuse- and six discrete-PAVF types. The PAVF-free rates at 1, 5, 10, 15, 20, and ≥25 years after Fontan operation were 97, 96, 93, 88, 87, and 83%, respectively. The mean arterial blood oxygen saturation (SaO2) in patients with diffuse PAVF at each corresponding postoperative stage were 90, 91, 91, 91, 89, and 88%, respectively, indicating lower SaO2 levels than those in patients without PAVF (all p < 0.01). However, there was no difference in the SaO2 levels between patients with discrete PAVF and those without PAVF. During a median follow-up period of 2.9 years after the last catheterization, 31 patients, including 12 patients with PAVF, died. Patients with PAVF, especially those with diffuse PAVF, had a higher mortality rate (p = 0.01) than those without PAVF (hazard ratio: 3.6, 95% confidence interval: 1.6–7.8, p = 0.0026).ConclusionPatients who underwent Fontan surgery had an increased incidence of PAVF as they aged. Discrete PAVF did not influence SaO2 or mortality, whereas the presence of diffuse PAVF caused hypoxia and was associated with all-cause mortality.

Inclusion of Hepatic Venous Drainage in Patients with Pulmonary Arteriovenous Fistulas

Hepatic venous blood has been thought to play some role as a vasoactive agent in the development of pulmonary arteriovenous fistulas in patients with congenital heart disease. During the last 15 years, we have observed pulmonary arteriovenous fistulas in 3, and systemic arteriovenous fistulas in 2, patients from our 16 cases of left isomerism. During the same period, neither pulmonary nor systemic arteriovenous fistulas were detected among 50 patients with right isomerism. Pulmonary arteriovenous fistulas had developed in the absence of surgery in 1 of the patients. Both pulmonary and systemic fistulas were detected in an another patient, in whom the hepatic venous blood bypassed the pulmonary circulation. The level of somatostatin, which is known to reduce splanchnic blood flow, was high in the systemic venous blood of this patient. Although the mechanism of development of the fistulas has yet to be clarified, we should be aware that not only pulmonary, but also systemic arteriovenous fistulas can be found in patients with left isomerism, even prior to any surgical intervention.

A 37-year-old female presented to our facility suffering from exertional dyspnea for 2-3 months. Her chest x-ray showed a nodular shadow in the right lower lung, and chest CT revealed a pulmonary arteriovenous fistula (PAVF). Subsequent echocardiographic examination detected no intra-cardiac shunt but did indicate pulmonary hypertension as evidenced by a tricuspid regurgitation flow velocity of 4.17 M/sec. Contrast echocardiography with antecubital vein injection of agitated normal saline demonstrated visualization of the left heart chambers compatible with PAVF. At cardiac catheterization, pulmonary arterial pressure was 59/26 mmHg, mean 34 mmHg. Because there was no intra-cardiac communication detected, primary pulmonary hypertension was tentatively diagnosed. Pulmonary angiography demonstrated a PAVF arising from the lower right pulmonary artery, forming a secular structure on its course in draining into the left atrium through a long pulmonary vein. In this particular anomaly, a concurrence of PAVF with pulmonary hypertension, we judged that the PAVF might serve as a safety valve for pulmonary hypertension and should not be closed. We therefore left the PAVF untreated and thereafter provided medical management for this patient. The concomitant presence of PAVF and pulmonary hypertension is a rare clinical condition. The ultimate treatment strategy for this uncommon condition should be carefully considered. Computed tomography; Contrast echocardiography; Pulmonary angiography; Pulmonary arteriovenous fistula; Pulmonary hypertension.

Successful occlusion of a large pulmonary arterio-venous fistula with Amplatzer septal occluder in a 16-year-old cyanotic boy

The cavopulmonary shunt procedure is now used for palliation of complex congenital heart lesions in infants. While pulmonary arteriovenous fistulae (PAVF) are a well-known complication of this surgery in older patients, no study of the prevalence of this condition in children and young infants has been reported. We compared 29 patients with cavopulmonary shunts or total caval exclusion with 53 control subjects evaluated by contrast echocardiography at the University of California, San Francisco. The primary cardiac lesion, age at the time of surgery, type of right heart bypass procedure, provision of auxiliary pulmonary blood flow, and changes in oxygen saturation over time were compared. The prevalence of PAVF in children after cavopulmonary anastomosis is 60%, higher than previously reported. The prevalence is significantly higher in infants < 6 months old and in those with a heterotaxy syndrome. The provision of an additional source of pulsatile, pulmonary blood flow appears to have little effect on the development of PAVF. Patients who developed PAVF had arterial oxygen saturations at the time of discharge from surgery similar to those who did not develop them. Those with PAVF had significantly lower arterial and pulmonary venous oxygen saturations at follow-up as a result of their intrapulmonary shunt. Contrast echocardiography provides a sensitive method for the detection of PAVF. While the origins, natural history, and ultimate clinical significance of PAVF in children after cavopulmonary anastomosis are unclear, surveillance by contrast echocardiography is indicated for all patients who have had this procedure because PAVF may cause significant intrapulmonary right-to-left shunting in some patients.

To demonstrate the use of transthoracic contrast echocardiography in the detection of pulmonary arteriovenous fistulas in patients with a previously constructed anastomosis between the superior caval vein and the right pulmonary artery (Glenn shunt), and to examine their prevalence in this special population, we evaluated prospectively all patients followed up in the Grown-Up Congenital Heart Unit subsequent to construction of a classical or bi-directional Glenn shunt. We studied 12 patients, aged from 21 to 38 (mean 28 ± 4.8) years who had had a previous cavopulmonary shunt in place for a period of 4 to 33 years (mean 24±9 years). All were examined with cross-sectional contrast echocardiography, 11 patients had cardiac catheterisation and angiography, and 6 patients had magnetic resonance imaging. Systemic arterial oxygen saturations at rest, and during exercise using the modified Bruce protocol, were measured in all patients. Contrast echocardiography showed evidence of pulmonary arteriovenous fistulas in 7 of the 12 patients, with appearance of echo contrast in the left atrium 1–8 seconds after peripheral venous injection in the arm. Simultaneous appearance of microbubbles in the right atrium revealed a residual communication between the superior caval vein and the right atrium in 2 patients, and presence of collaterals between the superior and inferior caval veins in one. Cardiac catheterisation and angiography showed obvious fistulas in 4 patients, and revealed suggestive findings in 2. In patients deemed to have pulmonary arteriovenous fistulas on contrast echocardiography, arterial oxygen saturations at rest (51–94%, mean 75±15.3%) and on exercise (23–91%, mean 53±24.2%) were significantly lower compared to patients judged to be without fistulas (p&lt;0.005). Pulmonary hypertension in the contralateral lung was more common in patients with fistulas (mean left pulmonary arterial pressure 22–110 mm Hg, p=0.014). In patients with cavopulmonary anastomoses, pulmonary arteriovenous fistulas occur frequently in the long term (10–33, mean 25.7±8 years), and are associated with worsening systemic arterial desaturation. Contrast echocardiography should be included in the regular evaluation of these patients as a simple and sensitive technique for the detection of pulmonary arteriovenous fistulas, particularly with the devel opment of increasing cyanosis.

Isolated pulmonary arteriovenous fistula (PAVF) leading to paradoxical embolism and stroke is rare, particularly in cases involving large vessel occlusions. Here, we present the case of a 69-year-old female with occlusion of the M2 segment of the middle cerebral artery (MCA) and stenosis of the common carotid artery (CCA) caused by PAVF, which mimicked artery-to-artery embolism. CT angiography revealed occlusion of the left M2 segment of the MCA and stenosis of the CCA. After administration of recombinant tissue plasminogen activator, both the left MCA occlusion and CCA stenosis were completely recanalized. Transthoracic contrast echocardiography revealed a significant right-to-left shunt both at rest and during the Valsalva maneuver, while chest CT angiography indicated the presence of PAVF in the lower lobe of the right lung. The anticoagulant medication rivaroxaban (15 mg) was administered to prevent the recurrence of ischemic stroke. Pulmonary arterial angiography confirmed the diagnosis of PAVF, and PAVF embolization using coils was successfully performed. At the one-year follow-up, the patient had no stroke recurrence. PAVF is a potentially fatal but treatable disease. Even in patients with large vessel occlusions, it is essential to consider PAVF as a rare underlying cause. The mechanism of PAVF-related stroke might be mistaken for artery-to-artery embolism.

Objective To describe the clinical characteristics of diffuse pulmonary arteriovenous fistulas (PAVFs) and to evaluate the methods of diagnosis and treatment.Methods Retrospective analysis of two patients with diffuse PAVFs who were diagnosed in Peking University First Hospital and the literatures on the subject were reviewed.Results Both patients presented with the triad of dyspnea on exertion,cyanosis,and clubbing.Case 1 was a woman with hereditary telangiectasia disease (HHT),who also presented with repeated epistaxis and facial telangiectasia.Case 2 was a man with hepatic cirrhosis,who presented with hepatopulmonary syndrome.Echocardiographies of 2 patients were both normal,peripheral vein contrast echocardiography showed abnormal filling of the left atrium with echo contrast material.Chest CT showed bilateral intrapulmonary artery dilatation,subpleural small nodular,reticular and patchy opacities.Pulmonary angiography showed that pulmonary circulation time was both shortened.Pulmonary angiography also showed that lower left dorsal segment artery and pulmonary vein were directly connected in case 2,and then tanscatheter embolization was carried out.However,oxygenation of this patientwasn't improved.Case 1 was alive and case 2 died of liver cirrhosis after 5-year follow up,neither of them had brain complications.Conclusions Diffuse PAVFs are clinically rare and present with the triad of dyspnea on exertion,cyanosis,and clubbing.Pulmonary angiography and contrast echocardiography are helpful for diagnosis. Key words: Diffuse pulmonary arteriovenous fistula; Hereditary haemorrhagic telangiectasia; Hepatopulmonary syndrome; Contrast echocardiography

A 53-year-old man presented with a history of depressant syndrome. He had been hospitalized 16 years previously because of penetrating traumatic injury of the left hemithorax by bullet secondary to a suicide attempt. Recently, he came to the emergency department for an illness leading to the discovery of severe hypoxemia refractory to nasal oxygen therapy. The arterial blood gas measurements revealed a pH of 7.41, a Paco2 of 41 mm Hg, a Pao2 of 45 mm Hg, and O2 saturation of 83% on ambient air; the Pao2 increased to 85 mm Hg on inspired oxygen of 100%. resulting in a shunt of 30%. Multidetector computed tomography–angiography of the chest showed clearly a giant proximal pulmonary arteriovenous fistula (Figure 1A and B and …

Lung perfusion impairment in patients with pulmonary arteriovenous fistula (AVF) was evaluated by automated deep inspiratory breath-hold (DIBrH) perfusion single-photon emission computed tomography (SPECT)-CT fusion images. Participants were 14 patients with a single (N=6) or multiple nodular AVFs (N=8) diagnosed by contrast-enhanced CT scan and/or pulmonary angiography. After the injection of 185MBq Tc-99m-macroaggregated albumin, a whole-body scan was obtained to quantify an intrapulmonary right-to-left shunt. Subsequently, DIBrH SPECT was obtained using the continuous rotating acquisition mode of a dual-headed SPECT system, which was automatically coregistered with DIBrH CT. The anatomic relationship between AVF and perfusion defects was assessed on the fusion images. The whole-body scan depicted systemic organs indicating the presence of an intrapulmonary right-to-left shunt in all the patients. DIBrH SPECT showed 34 perfusion defects in these patients, which were located at the AVF and in the surrounding lungs of the AVF on the fusion images, regardless of the absence of morphologic abnormality on CT in all the patients. These defects were considered to be caused by the 'steal phenomenon' associated with the high and fast pulmonary arterial flow to each AVF, which were more extensive and severe in the multiple AVFs compared with a single AVF (P=0.0012), occasionally extending to the entire lobe with AVF or even to the adjacent lobe. In five patients, the fusion images detected a total of six tiny AVFs with unexpectedly extensive 'steal phenomenon'-induced defects, which had been missed by other radiological imaging techniques. The summed value of the shunt index estimated by the whole-body scan and the lung perfusion defect extent estimated by DIBrH SPECT was significantly correlated with PaO2 in all the patients (P < 0.0001), with a better correlation compared with the shunt index alone. In addition to the right-to-left shunt, 'steal phenomenon'-induced perfusion defects are common in the surrounding lung of pulmonary nodular AVF and cause hypoxemia. DIBrH SPECT-CT fusion images contribute to the objective evaluation of 'steal phenomenon'-induced lung perfusion impairment in AVF and the detection of tiny, subtle AVFs that may be missed by other radiological imaging techniques.

The role of vascular imaging in the assessment of acute stroke has been debated for decades since the demonstration of intravenous tissue-type plasminogen activator (tPA) efficacy.1–3 It would seem logical that a disease involving the vasculature of the brain should require evaluation of that vasculature to best plan appropriate treatment. The major limitation to routine vessel imaging had been access to a modality that can provide this information noninvasively, accurately, and efficiently. Currently, there are 4 imaging modalities capable of providing vascular information in acute stroke. Given the high resource intensity and invasive nature of cerebral angiography, there is little place for this modality as a pure diagnostic tool in the acute stroke setting. The 3 noninvasive tests that could be used in acute stroke include computed tomographic (CT) angiography (CTA), magnetic resonance (MR) angiography (MRA), and transcranial Doppler (TCD)/transcranial color-coded sonography (TCCS)+carotid duplex sonography. This review will consider characteristics (Table 1) important for evaluating and comparing the 3 modalities as the diagnostic tool of choice for acute stroke assessment and treatment decision making. In the past, vascular imaging information did not significantly alter the evidence-based acute treatment plan, but this has now changed with new evidence for endovascular treatment renewing the debate on which should the standard imaging approach be if a patient presents acutely (<6 hours from onset) with acute disabling stroke symptoms? View this table: Table 1. Comparison of Vascular Imaging Techniques Each of the 3 modalities have different methods of acquisition but are all capable of imaging both the extracranial and intracranial arterial circulation. CTA is a CT technique that requires an injection of intravenous x-ray contrast in the arm with rapid movement of the CT gantry where x-ray information is gathered by a spiral or helical acquisition in 3-dimensional (3D) that starts usually at the aortic arch …

BackgroundWe report a patient with cytogenetically confirmed Fanconi anaemia with associated diffuse bilateral pulmonary arterio-venous fistulae. This is only the second reported case of diffuse pulmonary arterio-venous fistulae with Fanconi anaemia.Case PresentationA 16 year old Sri Lankan boy, with a cytogenetically confirmed Fanconi anaemia was admitted to University Medical Unit, National Hospital of Sri Lanka for further assessment and treatment. Both central and peripheral cyanosis plus clubbing were noted on examination. The peripheral saturation was persistently low on room air and did not improve with supplementary Oxygen. Contrast echocardiography failed to demonstrate an intra cardiac shunt but showed early crossover of contrast, suggesting the possibility of pulmonary arterio-venous fistulae. Computed tomography pulmonary angiogram was inconclusive. Subsequent right heart catheterisation revealed bilateral diffuse arterio-venous fistulae not amenable for device closure or surgical intervention.ConclusionTo our knowledge, this is the second reported patient with diffuse pulmonary arterio-venous fistulae associated with Fanconi anaemia. We report this case to create awareness among clinicians regarding this elusive association. We recommend screening patients with Fanconi anaemia using contrast echocardiography at the time of assessment with transthoracic echocardiogram. Though universal screening may be impossible given the cost constraints, such screening should at least be performed in patients with clinical evidence of desaturation or when a therapeutic option such as haematopoietic stem cell transplantation is considered. Treatment of pulmonary arteriovenous fistulae would improve patient outcome as desaturation by shunting worsens the anaemic symptoms by reducing the oxygen carrying capacity of blood.

Pulmonary arteriovenous malformations represent a direct communication between one or more pulmonary arteries and one or more pulmonary veins. Common anatomic forms include single sacs ranging from 1 to >10 cm in diameter, macroscopic tangles, and microscopic telangiectases. The main complications of pulmonary arteriovenous malformations are believed to relate to right-to-left shunting of blood through the pulmonary arteriovenous malformations and include stroke and brain abscess, which together occur in up to one half of patients if untreated. However, the association of pulmonary hypertension is not common. In this case, a young woman with a pulmonary arteriovenous fistula localized to the left lower lobe coexisting with pulmonary hypertension is described. A 42-year-old woman was evaluated for progressively worsening exertional dyspnea. Her past medical history was unremarkable. The electrocardiogram revealed sinus rhythm with right ventricular hypertrophy with strain. Transthoracic echocardiography showed enlarged right atrium and ventricle with elevated right ventricular systolic pressure (tricuspid regurgitant jet velocity 4.8 m/s). There was no evidence of pulmonic stenosis. Chest computed tomography was performed to rule out chronic pulmonary embolism and revealed multiple pulmonary arteriovenous fistulas on the left lung, the largest (17mm) on left lower lobe-posterior basal segment, middle on the left lower lobe-medial basal segment, and the smallest on anterior segment of left upper lobe (Fig. 1). Contrast echocardiography was performed by intravenous injection of hand-agitated saline while visualizing the atria. Contrast appears in the left atrium 3 to 5 seconds after it is seen in the right atrium, suggestive of pulmonary arteriovenous fistula (Fig. 2). On cardiac catheterization, peak systolic and diastolic pressures of main pulmonary artery were 90 and 35 mmHg, respectively. Mean pulmonary artery wedge pressure was 11 mmHg. Angiography revealed a huge pulmonary arteriovenous fistula in the middle and lower lobes of the left lung (Fig. 3). The patient decided to be treated conservatively and discharged.

Pulmonary arteriovenous malformations represent a direct communication between one or more pulmonary arteries and one or more pulmonary veins. Common anatomic forms include single sacs ranging from 1 to >10 cm in diameter, macroscopic tangles, and microscopic telangiectases. The main complications of pulmonary arteriovenous malformations are believed to relate to right-to-left shunting of blood through the pulmonary arteriovenous malformations and include stroke and brain abscess, which together occur in up to one half of patients if untreated. However, the association of pulmonary hypertension is not common. In this case, a young woman with a pulmonary arteriovenous fistula localized to the left lower lobe coexisting with pulmonary hypertension is described. A 42-year-old woman was evaluated for progressively worsening exertional dyspnea. Her past medical history was unremarkable. The electrocardiogram revealed sinus rhythm with right ventricular hypertrophy with strain. Transthoracic echocardiography showed enlarged right atrium and ventricle with elevated right ventricular systolic pressure (tricuspid regurgitant jet velocity 4.8 m/s). There was no evidence of pulmonic stenosis. Chest computed tomography was performed to rule out chronic pulmonary embolism and revealed multiple pulmonary arteriovenous fistulas on the left lung, the largest (17mm) on left lower lobe-posterior basal segment, middle on the left lower lobe-medial basal segment, and the smallest on anterior segment of left upper lobe (Fig. 1). Contrast echocardiography was performed by intravenous injection of hand-agitated saline while visualizing the atria. Contrast appears in the left atrium 3 to 5 seconds after it is seen in the right atrium, suggestive of pulmonary arteriovenous fistula (Fig. 2). On cardiac catheterization, peak systolic and diastolic pressures of main pulmonary artery were 90 and 35 mmHg, respectively. Mean pulmonary artery wedge pressure was 11 mmHg. Angiography revealed a huge pulmonary arteriovenous fistula in the middle and lower lobes of the left lung (Fig. 3). The patient decided to be treated conservatively and discharged.