Morphological Studies of Pulmonary Arteriovenous Shunting in a Lamb Model of Superior Cavopulmonary Anastomosis

We sought to identify and characterize the abnormal vascular structures responsible for pulmonary arteriovenous shunting following the Glenn cavopulmonary shunt. Superior cavopulmonary shunt is commonly performed as part of the staged pathway to total cavopulmonary shunt to treat univentricular forms of congenital heart disease, however, clinically significant pulmonary arteriovenous malformations develop in some patients after the procedure. The causes of pulmonary arteriovenous malformations and other pulmonary vascular changes that occur after cavopulmonary shunt are not known. Using a juvenile lamb model of superior cavopulmonary anastomosis that reliably produces pulmonary arteriovenous malformations, we performed echocardiography and morphological analyses to determine the anatomic site of shunting and to identify the vascular structures involved. Pulmonary arteriovenous shunting was identified by contrast echocardiography in all surviving animals (n = 40) following superior cavopulmonary anastomosis. Pulmonary vascular corrosion casts revealed abnormal tortuous vessels joining pulmonary arteries and veins in cavopulmonary shunt animals but not control animals. In conclusion, unusual channels that bridged pulmonary arteries and veins were identified. These may represent the vascular structures responsible for arteriovenous shunting following the classic Glenn cavopulmonary shunt. Detailed analysis of these structures may elucidate factors responsible for their development.     

A very rare case of polysplenia syndrome with congenital diffuse pulmonary arteriovenous fistulas

A five-year-old girl patient was admitted with cyanosis and dyspnea, which started from birth. She had small telangiectatic lesions on her face and cerebral arteriovenous malformation, but no family history of hereditary hemorrhagic telangiectasia. Contrast echocardiography and pulmonary angiography demonstrated diffuse pulmonary arteriovenous fistulas. The patient was diagnosed as polysplenia syndrome characterized with left atrial isomerism, interrupted inferior vena cava, azygous continuation to the superior vena cava, and hepatic veins draining to the right atrium. In contrast to the other polysplenia syndrome cases, in this patient, pulmonary arteriovenous fistulas were not associated with cavopulmonary anastomoses or liver disease.     

Plain radiographic,nuclear medicine and angiographic observations of hepatogenic pulmonary angiodysplasia

Clinical and radiological findings of hepatogenic pulmonary angiodysplasia are reported in two cases. Myriad spidery pulmonary blood vessels are seen on plain radiographs and verified with right to left intrapulmonary shunting on pulmonary angiogram and pulmonary isotopic perfusion scan. Pathophysiology and differential diagnosis are discussed. We propose that the term "pulmonary angio-dysplasia" should include: 1) Pulmonary telangiectasia 2) Hereditary hemorrhagic telangiectasia (Osler-Rendu-Weber syndrome) 3) Classical discrete pulmonary arteriovenous fistula 4) Hepatogenic pulmonary angiodysplasia: pulmonary arteriovenous communications with right to left shunting secondary to hepatic cirrhosis.     

Diffuse pulmonary arteriovenous fistula shown by contrast echocardiography and pulmonary angiography

We report an 11-year-old boy with diffuse pulmonary arteriovenous fistula (multiple telangiectasia type). Contrast echocardiography proved R to L shunting at the peripheral levels of the lungs. A definitive diagnosis was obtained by pulmonary arteriography.     

Regression of pulmonary arteriovenous malformations following heart transplantation

Pulmonary arteriovenous malformations (PAVMs) can occur following caval to pulmonary artery connection, Glenn and/or Fontan procedure, leading to severe cyanosis and exercise intolerance. It is unknown whether these abnormalities regress or persist following heart transplantation (HTx). Twenty patients with failed Fontan or Glenn procedures were screened for PAVMs prior to HTx by contrast echocardiography, selective pulmonary angiography, and pulmonary venous desaturation. Age at transplant, diagnosis, previous operations, time from Glenn to transplant, systemic oxygenation, hemoglobin level, and ventricular function were determined. The clinical course after HTx was characterized in three patients with significant PAVMs. Indications for HTx were exercise intolerance and severe cyanosis in one patient, and cyanosis and ventricular dysfunction in two. Pre-HTx, mean systemic saturation was 67%; mean pulmonary venous wedge saturation was 81%. Post-HTx, oxygen saturations were normal (> 96%) at 14, 40, and 180 days. Contrast echocardiography, performed 1 month to 3.3 yrs after HTx, showed no intrapulmonary shunting in two patients and minimal shunting in one. One patient suffered an embolic stroke from right-to-left shunting post-HTx. All patients are alive and well 35, 71, and 73 months post-HTx. In patients with single ventricle physiology, PAVMs are not an absolute contraindication to HTx. Heart-lung transplant may not be required for these patients.     

Redirection of Hepatic Drainage for Treatment of Pulmonary Arteriovenous Malformations Following the Fontan Procedure

The development of unilateral pulmonary arteriovenous malformations in patients after total cavopulmonary connection with an extracardiac conduit has been reported. Unequal distribution of hepatic venous flow to the lung is theorized to be the causative factor. We report the surgical management of pulmonary arteriovenous malformations in a patient with heterotaxy syndrome, single ventricle, and interrupted inferior vena cava. The patient had previously undergone a total cavopulmonary connection with an extracardiac conduit draining hepatic venous flow to the right branch pulmonary artery. In the subsequent operation, we redirected the extracardiac conduit to the innominate vein. This operation provided the affected lung with hepatic venous blood without exposing the patient to the morbidity associated with cardiopulmonary bypass.     

Postmortem demonstration of intrapulmonary arteriovenous shunting.

The measurement of the pressure required to drive a 2% solution of gelatin across the pulmonary vascular bed of a group of 49 infants dying suddenly at less than 44 weeks'' postnatal age, has shown the presence of low pressure arteriovenous shunting in 30 cases (61%). Injection of polymethylmethacrylate beads in three cases has demonstrated that the vessels that form the shunts are up to 60 microns in diameter. The presence of vessels allowing shunting at pressures as low as 0.1 kPa (1 cm H2O) could severely compromise the gas exchange function of the lung.     

Transcatheter Closure of Abnormal Vessels and Arteriovenous Fistulas With the Amplatzer Vascular Plug 4 in Patients With Congenital Heart Disease

Although vascular plugs allow the interventional closure of medium-sized to large abnormal vessels, their application is limited by the need for long sheaths or large guiding catheters. The authors report their experience with the new Amplatzer vascular plug 4 (AVP 4), a self-expanding spindle-shaped occluder made of Nitinol wire mash, which can be placed through 4-Fr catheters with an internal diameter of 0.038 in. or larger. From October 2009 until June 2012, 14 AVP 4 devices were deployed in 12 patients (ages, 0.3–48.8 years). Nine patients had venovenous or arteriovenous collaterals in functional univentricular hearts. One patient had pulmonary atresia with a ventricular septal defect and major aortopulmonary collateral arteries, and one patient had a pulmonary arteriovenous fistula. One child had a large coronary artery fistula to the right atrium. The authors used AVP 4 devices with diameters of 4–8 mm. In all the patients, the AVP 4 was implanted successfully. No occluder dislocations and no complications related to the procedure occurred. Complete vessel occlusion was achieved in seven cases. In seven additional cases, a residual shunt was present at the end of the procedure while the patients were still fully heparinized. In 2 of 14 vessels, the decision was made to place additional devices to abolish residual shunting. According to the authors’ experience, the AVP 4 allows safe and effective occlusion of medium-size and large abnormal vessels. It is also well suited for tortuous high-flow vessels such as coronary or pulmonary arteriovenous fistulas. In case of a suboptimal position, it is possible to reposition the occluder with ease. Further studies are needed to determine whether initial residual shunting in heparinized patients disappears during follow-up care. The AVP 4 represents a valuable new device for the interventional treatment of complex congenital vessel malformations.     

Pulmonary Arteriovenous Malformation in Patients with Total Cavopulmonary Shunt: What Role Does Lack of Hepatic Venous Blood Flow to the Lungs Play?

We examined the etiology of a long-term postoperative complication, pulmonary arteriovenous malformation (PAVM), in a patient who underwent total cavopulmonary shunt (TCPS). The patient underwent TCPS at the age of 3 years and 1 month, and a PAVM developed. At the age of 10 years, TCPS was switched to total cavopulmonary connection to facilitate circulation of hepatic venous blood to the pulmonary artery. As a result, oxygen saturation increased. These findings suggest that the absence of pulmonary circulation of hepatic venous blood is involved in the development of PAVM.     

Failure of liver transplantation in Wilson's disease with pulmonary arteriovenous shunting

A 12-year-old boy with Wilson's disease developed exertional dyspnea, cyanosis, and finger clubbing 10 months after diagnosis. The hypoxemia was caused by arteriovenous shunting, demonstrated by radionuclide scanning and pulmonary arteriography. Orthotopic liver transplantation was performed after the development of severe hypoxemia. There was no apparent reversal of the intrapulmonary arteriovenous shunting and he died 10 days posttransplantation of multiple organ failure secondary to hypoxemia. Monitoring arterial oxygen saturation in children with cirrhosis is warranted since the presence of significant arteriovenous shunting may influence prognosis and decisions regarding liver transplantation.     

Evaluation of patients undergoing Senning repair with two-dimensional contrast echocardiography

Summary The postoperative anatomy of the Senning interatrial diversion was defined by two-dimensional contrast echocardiography in ten patients. A modified apical four-chamber view proved most valuable, allowing for simultaneous visualization of both the systemic venous atrium and the pulmonary venous atrium. The anatomy was confirmed with two-dimensional contrast echocardiography utilizing catheters placed in the systemic venous atrium and pulmonary venous atrium at the time of surgery. In addition, in several of the patients, we were able to detect atrial or ventricular level shunts which were not clinically apparent. One patient who was judged to have a significant shunt by two-dimensional contrast echocardiography had no anatomic site found at autopsy to explain the shunting. We conclude that two-dimensional contrast echocardiography can define the postoperative anatomy following Senning repair allowing for immediate and future evaluation. Shunting at the atrial and ventricular levels can also be detected, but the method is very sensitive and difficult to quantitate or correlate clinically.     

Resolution of Acquired Pulmonary Arteriovenous Malformations in a Patient with Total Anomalous Systemic Venous Return

An 11-year-old male with total anomalous systemic venous return had surgical repair except for the hepatic venous return, which drained to the left atrium. He developed progressive cyanosis and fatigue and was diagnosed with large pulmonary arteriovenous malformations (PAVMs) during cardiac catheterization with the use of bubble contrast echocardiography. After surgical redirection of hepatic venous flow to the right heart and pulmonary arterial system, resolution of these PAVMs was demonstrated clinically and by contrast echocardiography. This unique case report demonstrates the development of PAVMs with exclusion of hepatic venous return through the pulmonary vascular bed while pulsatile pulmonary blood flow remains intact. It reinforces the likelihood of the absence of an as yet unidentified hepatic vasoactive substance as the source for development of PAVMs.     

Clinical Improvement After Banding of a Pulmonary Branch Artery in a Symptomatic Patient with Osler–Rendu–Weber Syndrome

We report a symptomatic newborn with Osler–Rendu–Weber syndrome, multiple and diffuse pulmonary arteriovenous malformations, and right-to-left shunting in the left lung. Right-to-left shunting was significantly decreased by selectively banding the left pulmonary branch artery and clipping one large feeding vessel so that total resection of the left lung could be avoided.     

Gaucher disease type I: analysis of two cases with thalassemic facies and pulmonary arteriovenous fistulas

Here we report two unusual patients with Gaucher disease type I. Both girls admitted with hepatosplenomegaly, growth retardation, and anemia at four and 2.5 years of age, and Gaucher cells were seen on bone marrow aspirates. Thalassemic face was first noted at 8 and 11 years of age, respectively, with frontal bossing and maxillary hypertrophia. Although they had unconjugated hyperbilirubinemia, high reticulocytes, polychromasia, and normoblasts on peripheral smear, other laboratory tests for hemolytic disease were negative. Radiological examination revealed typical bone involvement of Gaucher disease, as well as costal enlargement and obliteration of paranasal sinuses, the latter two reported in hemolytic diseases. Cyanosis, digital clubbing and recurrent lung infections led to contrast echocardiography that revealed diffuse pulmonary arteriovenous shunting in both. Diagnosis was confirmed by low leukocyte beta glucosidase levels and mutations N370S7/L444P (Case 1) and N370S/? (Case 2). These features, all reported for the first time, may show a new clinical course in Gaucher disease.     

Micropulmonary arteriovenous fistula causing cyanosis

This article presents a young girl who came to the Department of Pediatrics, AIIMS, with cyanosis and was diagnosed to be having multiple pulmonary arteriovenous fistulae. The cardiovascular evaluation was normal and so was the respiratory evaluation. The desaturation did not improve with oxygen. The chest X-ray was also normal. The echocardiogram did not reveal any abnormality but agitated saline contrast echocardiography suggested an extracardiac right to left shunt which was confirmed on pulmonary angiography.     

Cerebral Hemorrhage Associated with Sildenafil (Revatio) in an Infant

A case of cerebral hemorrhage associated with sildenafil (Revatio) use in an infant is presented. Sildenafil is increasingly used in the treatment of primary and secondary pulmonary arterial hypertension and pulmonary arteriovenous fistula. In the reported case, sildenafil used to treat pulmonary arteriovenous fistula improved right-to-left shunting across the pulmonary fistula but resulted in cerebral hemorrhage. Cerebral hemorrhage, a previously reported complication of sildenafil, developed in an infant after a rapid increase in dose, to 4.7 mg/kg/day. Therefore, sildenafil doses must be increased only with care, and cerebral hemorrhage must be considered a potential complication.     

Temporary Pulmonary Vein Stenosis During Intraoperative Transesophageal Echocardiography in Total Cavopulmonary Connection

Two patients operated on by one of the authors (MK) developed hemodynamic instability after otherwise uneventful completion of total cavopulmonary anastomosis with an extracardiac tube. In both, a stenosis of the right pulmonary veins was demonstrated during routine intraoperative transesophageal echocardiography. The transesophageal probe was found to be the underlying problem. Apparently, the pulmonary veins became compressed between the probe and the extracardiac conduit.     

Doppler flow profiles in the right and left pulmonary artery in children with congenital heart disease and a bidirectional cavopulmonary shunt

Summary The systolic and diastolic Doppler tracings in the right and left pulmonary artery were analyzed in 10 patients with complex cyanotic congenital heart disease, aged 6 months to 12 years (median 3 years), after employment of a bidirectional cavopulmonary shunt. The postoperative interval ranged from 2 weeks to 1.7 years (median 1.3 years). In children with pulmonary atresia or severe pulmonary stenosis with minimal antegrade pulsatile pulmonary blood flow Doppler echocardiography confirmed a systolic and diastolic bidirectional shunt from the vena cava superior to both pulmonary arteries. In children with pulmonary stenosis, Doppler echocardiography confirmed a systolic shunt only to the right pulmonary artery and a diastolic bidirectional shunt into both pulmonary arteries. As the left pulmonary artery was perfused by the pulsatile transvalvular flow it was difficult to detect a concomitant systolic Glenn-related flow in those patients. Quantitative analysis of the diastolic Doppler tracings revealed a significant difference in the velocity time integral in the right and left pulmonary artery indicating a dominant right lung perfusion in diastole.Deceased     

Color flow mapping to document normal pulmonary venous return in neonates with persistent pulmonary hypertension being considered for extracorporeal membrane oxygenation

This study investigated the value of color flow mapping in documenting normal pulmonary venous return in neonates with persistent pulmonary hypertension who were candidates for extracorporeal membrane oxygenation (ECMO). Forty newborn infants with persistent pulmonary hypertension underwent conventional (two-dimensional and Doppler) echocardiography and color flow mapping. Of 25 candidates for ECMO therapy, 18 subsequently received it. Conventional echocardiography demonstrated normal pulmonary venous return in only 21 of the 40 patients. In all 40, however, color flow mapping demonstrated normal right and left pulmonary venous drainage entering the left atrium. In three other patients with total anomalous pulmonary venous return, conventional echocardiography demonstrated the anomalous pulmonary venous pathways, and color flow mapping did not show jets emanating from the left atrial wall; the left atrium was shown to fill exclusively from right to left shunting through the foramen ovale. We conclude that color flow mapping is superior to conventional echocardiography for verifying normal pulmonary venous return in neonates with persistent pulmonary hypertension.     

Pulmonary arteriovenous malformations

Pulmonary arteriovenous malformations rarely present in childhood. Two cases are presented in this report. Both the cases presented clinically with cyanosis and clubbing without a cardiac murmur. The second case had cerebral abscess in addition. Both the cases underwent a contrast-enhanced echocardiography which suggested the presence of pulmonary arteriovenous malformations. The first case also underwent^99mTc radionuclide scan and pulmonary angiography. The cases are being reported for their characteristic clinical features and for emphasizing the role of non-invasive modalities like contrast-enhanced echocardiography and radionuclide scan in reaching the diagnosis.