Systemic Arteriovenous Fistula Research Articles

Congenital systemic arteriovenous fistulas: Interventional strategies and embryological perspectives.

Background:Data on congenital systemic arteriovenous fistulas are largely based on individual case reports. A true systemic arteriovenous fistula needs to be differentiated from other vascular malformations like capillary or venous hemangiomas, which are far more common.Objectives:We sought to identify the varied symptoms, diagnostic challenges, describe interventional treatment options, and postulate an embryological basis for this uncommonly described entity.Methods:This is a descriptive study of a cohort of systemic arteriovenous fistulas seen in the department of pediatric cardiology at a tertiary cardiac institute from 2010 to 2020, with prospective medium-term follow-up. A total of seven cases were identified. The diagnosis was confirmed by computed tomographic imaging, magnetic resonance angiography, or conventional angiography.Results:All were successfully closed using duct occluders or embolization coils with no recurrence in six cases over a median duration of follow-up of 48 months (interquartile range: 16; 36–52 months). Four of the seven cases underwent follow-up imaging using echocardiography or ultrasound.Conclusion:The incidence of congenital systemic arteriovenous fistulas is low and accounted for 0.009% of pediatric outpatients seen over 10 years at our institute. The spectrum of clinical presentation varies from an innocuous swelling or a pulsating mass to frank heart failure. Strong clinical suspicion and advanced imaging modalities have helped identify some hitherto undescribed connections. Large malformations with multiple communications may persist or recur despite transcatheter closure.

Important Newborn Cardiac Diagnostic Dilemmas for the Neonatologist and Cardiologist–A Clinical Perspective

Most congenital heart disease (CHD) is readily recognisable in the newborn. Forewarned by previous fetal scanning, the presence of a murmur, tachypnoea, cyanosis and/or differential pulses and saturations all point to a cardiac abnormality. Yet serious heart disease may be missed on a fetal scan. There may be no murmur or clinical cyanosis, and tachypneoa may be attributed to non-cardiac causes. Tachypnoea on day 1 is usually non-cardiac except arising from ventricular failure or a large systemic arteriovenous fistula. A patent ductus arteriosus (PDA) may support either pulmonary or systemic duct dependent circulations. The initially high pulmonary vascular resistance (PVR) limits shunts so that murmurs even from large communications between the systemic and pulmonary circulations take days/weeks to develop. At times despite expert input, serious CHD maybe difficult to diagnose and warrants close interaction between the neonatologist and cardiologist to reach a timely diagnosis. Such conditions include obstructed total anomalous pulmonary venous connections (TAPVC) and the need to distinguish it from persistent pulmonary hypertension in the newborn (PPHN)–the treatment of the former is surgical the latter medical. A large duct shunting right to left may overshadow a suspected hypoplastic aortic isthmus and/or coarctation. Is the right to left shunting because of severe aortic obstruction or resulting from a high PVR with little obstruction. The diagnosis of pulmonary vein stenosis (PVS) remains problematic often developing in premature infants with ongoing bronchopulmonary dysplasia (BPD), still being cared for by the neonatologist. While there are other diagnostic dilemmas including deciding the contribution of a recognised CHD in a sick neonate, this paper will focus on the above-mentioned conditions with suggestions on what may be done to arrive at a timely diagnosis to achieve optimal outcomes.

Underlying Causes of High Output Heart Failure

In the U.S., each year, there are more than 500,000 new cases of all types of heart failure. With high output cardiac failure, there is an elevated cardiac output associated with several conditions and diseases, including obesity, chronic anemia, systemic arterio-venous fistula, hypercapnia, mitochondrial dysfunction, and hyperthyroidism. The underlying pathophysiologic mechanisms relate to a reduction in systemic vascular resistance from arterio-venous shunting or peripheral vasodilation. Often there is a decrease in systemic arterial blood pressure and neurohormonal activation leading to heart failure symptoms of dyspnea and fatigue. In a persistent high output state, patients may experience tachycardia, valvular abnormalities, and ventricular dilatation and/or hypertrophy. In this article, there is a review of high output heart failure, including the prevalence, pathophysiology, and common clinical causes of this disease.

Coexisting complex coronary fistula and systemic arteriovenous fistula in a middle-aged long-distance runner: demonstration with coronary CTA

Coexisting complex coronary fistula and systemic arteriovenous fistula in a middle-aged long-distance runner: demonstration with coronary CTA

Arteriovenous fistula between descending aorta: and left inferior pulmonary vein

Congenital systemic arteriovenous fistula arising from aorta and draining through the pulmonary vein to left atrium without lung sequestration is a rare vascular malformation [1,2]. On physical examination there is usually a continuous or systolic murmur. Clinical presentation depends upon the size and place of the vascular malformation [3]. If there is a suspicion of arteriovenous fistula on physical examination and echocardiography, multislice computed tomography angiography (CTA) can be helpful in confirming diagnosis and anatomic model, and choosing appropriate treatment modality [3,4]. We describe a rare case with arteriovenous fistula between thoracic aorta and left inferior pulmonary vein occluded with Amplatzer vascular plugs. A 20 month old girl with failure to thrive and cardiac murmur was referred by a pediatrician with suspected congenital heart diseases for an echocardiography. Her weight and height were 9 kg (<3% percentile) and 78 cm (10-25% percentile). Physical examination confirmed the presence of Grade III/VI systolic murmur heard on apical region and radiated to the mid scapular region posteriorly. There were a hyper dynamic pulse at the rate of 110/ min, forceful left ventricular apex impulse and mild hepatomegaly. There was no cyanosis or clubbing. Chest radiography showed mild cardiomegaly (cardio thoracic ratio 0.54) with increased pulmonary vascular markings especially in the lower left pulmonary region. The patient has mild congestive heart failure clinically. Echocardiography revealed left atrial and ventricular enlargement, moderately mitral valve regurgitation and increased blood flow into left atrium from enlarged left inferior pulmonary vein. An abnormal vessel that demonstrated a communication with the left inferior pulmonary vein was noted nearly to the left atrium. Diagnosis of the patient may be arteriovenous malformation/fistula but was not clear. Hence multislice CTA was done which revealed an abnormal communication, arteriovenous fistula, originating from thoracic aorta and draining into left inferior pulmonary vein (FIGURE 1 & VIDEO 1). The fistula drained through the left inferior pulmonary vein to the left atrium leading to left-to-left shunt. Lung had normal bronchial connection and pulmonary vasculature. Thoracic aortogram revealed an arteriovenous fistula originating from thoracic aorta and draining to left inferior pulmonary vein, and finally into left atrium (VIDEO 2). That was closed with embolization of Amplatzer vascular plugs. Post procedure Mustafa Kosecik

0458: Outcomes of pediatric hypertrophic cardiomyopathy associated with Rasopathy

The outcomes of pediatric hypertrophic cardiomyopathy (HCM) associated to RASopathies are scarcely known. To describe outcomes of pediatric HCM associated with RASopathy. 80 cases of children with a clinical phenotype of RASopathy and HCM were included. Age at diagnosis of HCM was 11.7 months (range 0 to 168). The HCM was diagnosed prenatally in 9 cases, and before one year of age in 58 cases. 67 had Noonan syndrome, 9 had Cardiofacio-cutaneous syndrome, 3 had Costello syndrome, and 1 had Noonan syndrome with multiples lentigines. The HCM was obstructive in 37 cases. Associated cardiac defects were right ventricular outflow tract obstruction in 40 children, polyvalvular dysplasia in 18, atrial septal defect (ASD) in 13, ventricular septal defect in 3, congenital mitral regurgitation in 2, persistent arterial duct in 2, left superior caval vein in 2, aortic arch anomaly in 2, coronary anomaly in 1, and systemic arteriovenous fistula in 1. Nineteen children underwent a Konno operation for obstructive HCM. Additional surgical procedures were 9 right ventricular outflow tract surgical reliefs, 9 percutaneous dilatations of pulmonary valve stenosis, 4 percutaneous closures of ASD, 1 tricuspid valve repair, 1 Brom procedure with aortic valve repair, 1 aortic valve replacement, and 1 coronary artery bypass. Overall mortality was 21%. Fourteen (82%) deaths occurred before 1 year of life. Causes of death were cardiac in 10 cases including two sudden deaths, related to respiratory diseases causes in 5, and in utero fœtal death in 1. Factors predicting mortality were diagnosis before 2 months of life (HR=4,33, p<0,001), fœtal diagnosis of HCM (HR=3,64, p<0,001), and surgery before one year of life (HR=3,43, p=0,001). Mortality of children with HCM due to RASopathy is high and occurs early in life. Main risk factors are early diagnosis of HCM including prenatal diagnosis, and need for surgery before one year of life.

Coronary arteriovenous fistula causing hydrops fetalis.

Fetal heart failure and hydrops fetalis may occur due to systemic arteriovenous fistula because of increased cardiac output. Arteriovenous fistula of the central nervous system, liver, bone or vascular tumors such as sacrococcygeal teratoma were previously reported to be causes of intrauterine heart failure. However, coronary arteriovenous fistula was not reported as a cause of fetal heart failure previously. It is a rare pathology comprising 0.2–0.4% of all congenital heart diseases even during postnatal life. Some may remain asymptomatic for many years and diagnosed by auscultation of a continuous murmur during a routine examination, while a larger fistulous coronary artery opening to a low pressure cardiac chamber may cause ischemia of the affected myocardial region due to steal phenomenon and may present with cardiomyopathy or congestive heart failure during childhood. We herein report a neonate with coronary arteriovenous fistula between the left main coronary artery and the right ventricular apex, who presented with hydrops fetalis during the third trimester of pregnancy.

Development of High-Output Heart Failure after Correction of Central Venous Occlusion: A Case Report

Temporary or permanent central venous catheter (CVC) insertion has been performed frequently for hemodialysis treatment. One of the most important long-term complications of CVC is the central venous occlusion (CVO). Treatment of CVO consists of percutaneous angioplasty (PTA), PTA and stent implantation, or surgical procedure for resistant occlusions. Clinical outcome and long-term results of the revascularization procedures are well documented. However, there is no clear information about acute medical complications of the procedures. High-output heart failure (HOHF) is associated with several diseases including chronic anemia, psoriasis, systemic arteriovenous fistula, sepsis, hypercapnia, multiple myeloma, and hyperthyroidism. Herein, we report a case of chronic kidney disease with CVO that developed acute HOHF immediately after the revascularization procedure (PTA and stenting).

Systemic arteriovenous fistulae for end-stage cyanosis after cavopulmonary connection: A useful bridge to transplantation

Intractable cyanosis after partial or complete cavopulmonary connection may rarely be managed by creating a systemic arteriovenous fistula. We investigated the long-term performance of arteriovenous fistulae. All 21 patients who received an arteriovenous fistula at The Hospital for Sick Children since the 1950s were investigated using parametric competing risk techniques. Primary arteriovenous fistula indication was (1) suboptimal pulmonary blood flow (N = 15) or (2) pulmonary shunting via pulmonary arteriovenous malformations (N = 6). Arteriovenous fistula longevity was determined by time to "occlusion" (absence of arteriovenous fistula flow via surgical ligation or spontaneous occlusion). All 21 patients had previously undergone second-stage palliation (Glenn shunt = 13; bidirectional shunt = 9). Five patients had undergone Fontan completion. Death in the presence of a functioning arteriovenous fistula occurred in 5 patients. Patients with bidirectional shunts had a significantly higher risk of death with a functioning arteriovenous fistula in situ (P = .04). High hemoglobin concentrations were associated with best outcome, and levels less than 170 g/L were associated with a high risk of death despite a functioning arteriovenous fistula (P < .01). Arteriovenous fistula occlusion occurred in 10 patients. Earlier occlusion was associated with previous Fontan completion (P = .02) and pulmonary arteriovenous malformations (P = .03). Surgical ligation during cardiac transplantation was the cause of occlusion in 7 patients. In these 7 patients, the arteriovenous fistula functioned for a median of 4.8 years. After transplantation, survival was 67% + or - 19% at 5 years. Overall survival was 73% + or - 10% 15 years after receiving an arteriovenous fistula (longest survival, 27.3 years). In patients with adequate hematocrit, arteriovenous fistula offers an effective bridge to transplantation when a high-risk Fontan procedure is deferred. Performance is best after unidirectional cavopulmonary connection and worse in the presence of pulmonary arteriovenous malformations. Survival is 75% at 15 years, despite being considered end stage.

Percutaneous Embolization of Vascular Fistulas Using Coils or Amplatzer Vascular Plugs

A great variety of different types of vascular fistula are referred to cardiac catheterization laboratories for diagnosis and percutaneous occlusion. In addition, a wide range of devices is available for treating them percutaneously. The objectives of this study were to assess the usefulness and difficulty of treating vascular fistulas percutaneously using controlled-release coils or Amplatzer vascular plugs and to report on the complications and overall outcomes observed with these two devices. Retrospective review of percutaneous embolizations performed from January 2004 through June 2008. In total, 51 vascular fistulas in 30 patients aged from 6 days to 28 years (mean, 8.4 years) underwent successful embolization. The underlying diagnoses were: 27 venous collaterals in 16 patients after the Glenn procedure, four surgical (i.e. Blalock-Taussig) fistulas, 11 pulmonary arteriovenous fistulas in three patients, two aortopulmonary collateral arteries in two patients, one venous collateral in a patient who underwent the Fontan procedure, one aortopulmonary artery fistula in a patient with Scimitar syndrome, one coronary arteriovenous fistula, three systemic arteriovenous fistulas in a newborn, and one fistula from the left atrium to the superior vena cava after the repair of anomalous pulmonary venous return. The lesions were treated percutaneously using 34 vascular plugs and 19 coils. Vascular fistulas can be occluded percutaneously with good Small fistulas can be closed using coils, while vascular plugs are preferable for large lesions. Both devices are highly effective as occluders and no particular difficulty or significant complication was observed.

High output heart failure

The symptoms and signs of heart failure can occur in the setting of an increased cardiac output and has been termed 'high output heart failure'. An elevated cardiac output with clinical heart failure is associated with several diseases including chronic anaemia, systemic arterio-venous fistulae, sepsis, hypercapnia and hyperthyroidism. The underlying primary physiological problem is of reduced systemic vascular resistance either due to arterio-venous shunting or peripheral vasodilatation. Both scenarios can lead to a fall in systemic arterial blood pressure and neurohormonal activation leading to overt clinical heart failure. In contrast to low output heart failure, clinical trial data in this area are lacking. The use of conventional therapies for heart failure, such as angiotensin converting enzyme inhibitors, angiotensin receptor blockers and certain beta-blockers with vasodilatory properties, is likely to further reduce systemic vascular resistance resulting in deterioration. The condition, although uncommon, is often associated with a potentially correctable aetiology. In the absence of a remediable cause, therapeutic options are very limited but include dietary restriction of salt and water combined with judicious use of diuretics. Vasodilators and beta-adrenoceptor positive inotropes are not recommended.

Creation of a Brachial Arteriovenous Fistula for Treatment of Pulmonary Arteriovenous Malformations After Cavopulmonary Anastomosis

Pulmonary arteriovenous malformations (PAVMs) occur in approximately 20% of patients after unidirectional superior cavopulmonary anastomosis (CPA), and frequently after bidirectional CPA in patients with polysplenia syndrome. It is hypothesized that exclusion of a growth-modulating factor produced in the liver may predispose to PAVM formation. Resolution of PAVMs after inclusion of hepatic venous effluent into the cavopulmonary circulation has been reported. An upper extremity systemic arteriovenous (AV) fistula may be created to augment pulmonary blood flow and improve oxygenation in hypoxemic patients with CPA, but there has been no systematic investigation of the effects of such fistulas on PAVMs after CPA. We studied 11 patients with PAVMs who underwent creation of a brachial AV fistula a median of 11 years after CPA. Eight patients had discontinuous pulmonary arteries or unilateral flow of a bidirectional CPA and were not considered good candidates for Fontan completion; the other 3 patients had polysplenia and unilateral hepatic venous streaming after Fontan completion. Three patients died of progressive complications of their heart disease 4 to 18 months after AV fistula creation. Pulmonary arteriovenous malformations resolved after creation of a brachial AV fistula in 4 of 5 surviving patients with unilateral flow of a superior CPA, but in none of 3 patients with polysplenia who had unilateral hepatic venous streaming after Fontan completion and PAVMs in the contralateral lung. These findings are consistent with the "hepatic factor" hypothesis, according to which the development of PAVMs is facilitated when an unidentified factor produced or metabolized in the liver does not reach the pulmonary circulation before traversing another capillary bed. Patients with unilateral superior CPA flow and PAVMs who are not considered candidates for Fontan completion may benefit from a brachial AV fistula.

Congenital systemic arteriovenous fistula between the distal thoracic aorta and hemiazygos vein in a child

Congenital systemic arteriovenous fistula between the distal thoracic aorta and hemiazygos vein in a child

Surfactant phospholipids and proteins are increased in fetal sheep with pulmonary hypertension secondary to fetal systemic arteriovenous fistula

To determine whether prenatal surfactant storage was altered in a model of systemic arteriovenous fistula (SAVF) with pulmonary hypertension, a fistula was created between the internal jugular vein and the carotid artery in 120-day fetal lambs, and surfactant material was explored at 134 days. Total phospholipids (TPL) and disaturated phosphatidylcholine (DSPC) were increased in whole lung tissue. Phospholipid analysis of isolated lamellar body fraction evidenced a specific increase of surfactant pool size: TPL and DSPC in this fraction were enhanced 1.9 and 2.9 times, respectively, when referred to DNA. Although the steady-state level of transcripts of surfactant protein (SP)-A and SP-B was not found to be changed at the time of death, semiquantitative Western blot analysis revealed elevated SP-A and SP-B protein contents three- and twofold, respectively. These findings indicate markedly enhanced accumulation of surfactant material in the presence of surgically induced prenatal pulmonary hypertension. Although total lung cell number was increased by 26%, SP-B immunolabeling indicated that increased surfactant amount did not result from an increased alveolar type II cell proportion, but rather from an increased rate of storage. Whether similar changes in surfactant are encountered in human neonates with persistent pulmonary hypertension is worthy of investigation.

Noninvasive assessment of fetal pulmonary blood flow in experimental pulmonary hypertension in the fetal lamb.

The aim of this study was to assess pulmonary arterial blood flow changes induced by the creation of a systemic arteriovenous fistula (120 d gestation) in the fetal lamb using Doppler technique. Doppler echocardiographic assessment of the pulmonary artery blood flow performed 1, 6, and 14 d after surgery showed that mean pulmonary arterial blood flow in the left or right pulmonary artery was 224 +/- 58 mL/min at day 1 in the fistula group, significantly higher than in the control group (113 +/- 22 mL/min; p < 0.01, ANOVA test) whether no difference was found at days 6 and 14. The mean inner diameter of the left pulmonary artery measured on postmortem lung arteriograms compared favorably to the one measured on day 14 at the same level on ultrasound. The mean left pulmonary arterial blood flow, measured at birth on day 14 after surgery, using ultrasonic flow transducer, was not statistically different from the one measured by Doppler on day 14. Our data demonstrate that echocardiography allows accurate assessment of pulmonary arterial blood flow in utero, providing evidence suggesting transient high pulmonary blood flow that did not last >6 d after the creation of a systemic fistula.

Pulmonary Hypertension in the Setting of Acquired Systemic Arteriovenous Fistulas

We describe 2 patients who presented with symptoms and clinical evidence of pulmonary hypertension. The first patient, who had severe pulmonary hypertension, underwent correction of an acquired arteriovenous (AV) fistula, which led to improvement according to clinical and noninvasive hemodynamic criteria. The second patient had severely symptomatic pulmonary hypertension associated with a large, previously unrecognized, superior mesenteric AV fistula after intra-abdominal surgery. Surgical correction of the fistula resulted in normalization of pulmonary hemodynamics assessed by right heart catheterization. Truly reversible substrates of pulmonary hypertension are rare. Acquired systemic AV fistulas are a less recognized cause of secondary pulmonary hypertension. It is unknown whether high blood flow peripheral AV shunts ultimately lead to endothelial proliferation, vascular smooth muscle hypertrophy, plexiform lesions, and other histopathologic changes that are seen in patients with left-to-right shunts due to atrial septal defects, ventricular septal defects, and patent ductus arteriosus.

Systemic arteriovenous fistula leads to pulmonary artery remodeling and abnormal vasoreactivity in the fetal lamb.

Several cases of systemic arteriovenous fistula diagnosed in the human fetus have been associated with the postnatal development of persistent pulmonary hypertension. The aim of this study was to determine the effects of a prenatally created systemic arteriovenous fistula on the structure and reactivity of the pulmonary circulation in the fetal lamb. A fistula between the jugular vein and carotid artery was created in fetal lambs at 119-124 days of gestation. At delivery (134-139 days), left pulmonary artery (LPA) pressure was increased in the fistula group (n = 12) compared with controls (n = 11, P < 0.01). The pulmonary vascular resistance was significantly higher in the fistula group (P < 0.05), whereas mean LPA blood flow was not statistically different between the two groups. Morphometric analysis of the pulmonary vascular bed revealed an increase in the number of peripheral muscular arteries, together with an increase in pulmonary arterial medial thickness in the fistula group. There was no difference in the relative number or size of intraacinar arteries. In vitro organ bath studies on pulmonary arterial rings showed impaired endothelium-dependent relaxation in the fistula group compared with controls. However, endothelial nitric oxide synthase protein expression was similar in both groups, whereas endothelium-independent relaxation to sodium nitroprusside was greater in the fistula group compared with controls. A systemic arteriovenous fistula leads to both structural and functional alteration of the pulmonary vasculature, which might lead to the development of persistent pulmonary hypertension after birth.

The effect of a systemic arteriovenous fistula on the pulmonary arterial blood pressure in the fetal sheep.

In order to investigate whether systemic arteriovenous fistula occurring during the fetal period could induce pulmonary hypertension at birth, a fistula was surgically created between the carotid artery and jugular vein of fetal lambs at 120 days' gestation. Mean pressures in the left pulmonary artery, aorta, atrium and ventricles were measured at birth in seven experimental animals and in five control animals. Mean left pulmonary pressure was significantly higher in the lambs with fistula as compared with the control group, suggesting that prenatal occurrence of systemic arteriovenous fistula may induce fetal pulmonary hypertension. The present study provides a new animal model that could be relevant for the study of mechanisms regulating pulmonary vascular tone in the perinatal period.

Chest wall arteriovenous fistula: an unusual complication after chest tube placement

Posttraumatic arteriovenous fistulas can form between vessels of the thorax that have sustained loss of integrity to the vessel wall. Although most are caused by injuries as a consequence of missile penetration or stab wounds, iatrogenic damage is a potential cause. Herein we present a case of a systemic arteriovenous fistula involving an intercostal artery and subcutaneous vein after chest tube placement.

Pulmonary and systemic arteriovenous fistulas in patients with left isomerism.

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.