Pulmonary Arteriovenous Shunting Research Articles

Clinical and echocardiographic features of platypnea-orthodeoxia syndrome: a single-centre experience

Abstract Funding Acknowledgements Type of funding sources: None. Background Platypnea-orthodeoxia syndrome (POS) is an uncommon condition characterized by dyspnoea and hypoxemia in the upright position that improves with recumbency.1 Possible causes are intracardiac shunt, pulmonary arteriovenous shunt, and V/Q mismatch.1,2 Echocardiography is the cornerstone of POS diagnosis, with special focus on atrial septal defect (ASD) morphology and right-to-left shunt confirmation.3 Purpose To evaluate the clinical and echocardiographic features of patients presenting with POS due to a cardiac cause. Methods We performed a retrospective analysis of patients diagnosed with POS in our centre between 2015 January and 2021 August. Routine blood tests and transthoracic echocardiogram (TTE) were performed in all patients. Demographics, clinical presentation, blood test results, TTE information, and PFO closure procedure details were recorded. Results Seven patients were included, 85.7% female (n = 6). The median (IQR) age was 78 (72-85) years. The most prevalent cardiovascular risk factors were hypertension (100%; n = 7) and overweight/obesity (85.7%; n = 6). Two patients (28.6%) had chronic pulmonary disease. The most common symptoms were fatigue and exercise intolerance (n= 5; 71.4%) and the most frequent sign was persistent hypoxemia (n = 7; 100%), although 28.6% (n = 2) patients did not present the typical positional changes in peripheral oxygen saturation. Haemoglobin levels [14.1 (13.3-15.2)] were within the normal range and serum NTproBNP levels [656 (287-1196)] were slightly elevated. Left ventricle function was preserved in all patients; right ventricle morphology and function were normal in 85.7% (n = 6) patients, low probability of pulmonary hypertension in TTE was found in 85.7% (n = 6), and exuberant Eustachian valve was observed in 14.3% (n = 1). All patients presented atrial septal hypermobility, 87.5% (n = 6) meeting atrial septal aneurysm criteria. Patent foramen ovale was found in 85.7% of patients (n = 6) and ostium secundum ASD in 14.3% (n = 1). POS precipitating factors were aortic root dilation (28.6%; n = 2), chest trauma (14.3%; n = 1), right hip arthroplasty (14.3%; n = 1), atrial septal stretching regarding right volume overload (14.3%; n = 1). The underlying mechanism was unknown in 28.6% (n = 2) of patients. ASD closure was performed in 57.1% (n = 4) of patients: 75% (n = 3) showed residual shunt, but clinical improvement was reported by all. No acute complications were described, except for paroxysmal atrial fibrillation (14.3%; n = 1). Conclusion POS diagnosis depends on high clinical suspicion: the most common manifestations are fatigue and persistent hypoxemia. Typical positional changes in oxygen saturation are not present in all patients. Polycythaemia, right chambers dilation, and pulmonary hypertension are not common. Echocardiography is fundamental for diagnosis, allowing right-to-left shunt confirmation and ASD morphology evaluation to outline a successful closure procedure.

PAY ATTENTION! AN UNUSUAL CASE OF DYSPNEA

SESSION TITLE: Medical Student/Resident Cardiothoracic Surgery Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Platypnea-orthodeoxia is an uncommon syndrome characterized by dyspnea and hypoxemia in upright position that improves with recumbent position. It can occur due to intracardiac shunts, pulmonary arteriovenous shunts and ventilation perfusion mismatch. We present a unique and rare cause of platypnea-orthodeoxia syndrome. CASE PRESENTATION: A 68 years old man with history of coronary artery disease and COPD presented with acute onset chest pain and associated difficulty breathing. Patient did have several months’ history of exertional dyspnea which did not improve with rest this time. On presentation, patient was noted to be hypoxic with oxygen saturation of 88% and ABG showed PH 7.41, PaO2 47 mmHg and PaCO2 22.4 mmHg. Oxygen saturation improved to 94% with 3L of supplemental oxygen. EKG and troponin were unremarkable. CT PE was unremarkable for pulmonary embolism as well. IV heparin drip was started for suspected unstable angina and patient underwent cardiac catheterization that revealed non-obstructive coronary artery disease. Echocardiography showed ejection fraction of 55-60% with mild mitral and tricuspid regurgitationDuring the course of hospitalization, patient was noted to have intermittent positional hypoxemia. He had normal resting saturation on 2 L of oxygen which dropped to 88% sitting upright and dropped to 84% on 2 L of oxygen upon raising both arms. Platypnea-orthodeoxia syndrome was strongly suspected with possible intra-cardiac or intrapulmonary shunt. Meanwhile, CT chest was unremarkable for interstitial lung disease. Right heart catheterization revealed normal right atrial RA (68.9%) and pulmonary arterial PA (68.3%) saturation at rest but reduced RA (42.5%) and PA (43.2%) saturation with sitting up. Echocardiography with bubble study showed right-to-left shunting and trans-esophageal echocardiography revealed a small 0.5 cm atrial septal defect (ASD) with bidirectional shunting. Patient was diagnosed with Platypnea-orthodeoxia syndrome secondary to ASD. He was discharged home on supplemental oxygen and outpatient follow-up for ASD closure. DISCUSSION: Platypnea-orthodeoxia is a rare syndrome. Patent foramen ovale is the most common cardiac cause of platypnea-orthodeoxia syndrome followed by ASD. Transesophageal echocardiography is the best test to diagnose atrial septal defect but it is important to rule out pulmonary causes of platypnea-orthodeoxia syndrome as well. ASD is successfully treated with percutaneous closure and prognosis of is good after correction of the defect. CONCLUSIONS: Platypnea-orthodeoxia syndrome is rare syndrome but it can be easily recognized with careful history and physical examination. Reference #1: Henkin S, Negrotto S, Pollak PM, Cullen MW, O'Cochlain DF, Wright RS. Platypnea-Orthodeoxia Syndrome: Diagnostic Challenge and the Importance of Heightened Clinical Suspicion. Tex Heart Inst J. 2015;42(5):498-501. Published 2015 Oct 1. doi:10.14503/THIJ-14-4596 Reference #2: Kazawa S, Enomoto T, Suzuki N, et al. Platypnea-orthodeoxia Syndrome in a Patient with an Atrial Septal Defect: The Diagnosis and Choice of Treatment. Intern Med. 2017;56(2):169-173. doi:10.2169/internalmedicine.56.7728 Reference #3: PLATYPNEA ORTHODEOXIA SYNDROME: A RARE COMPLICATION OF IATROGENIC ATRIAL SEPTAL DEFECT. Bharat Avirneni, Christopher Rosse, Joseph Choo, Kalpan Desai. J Am Coll Cardiol. 2020 Mar, 75 (11 Supplement 1) 2799. DISCLOSURES: No relevant relationships by Muhammad Aamir, source=Web Response No relevant relationships by Muhammad Afzal, source=Web Response No relevant relationships by Saleha Dar, source=Web Response

Patent ductus venosus and exercise related pulmonary hypertension: a case of a young adult with successful surgery closure

The patent ductus venosus is an embryological portosystemic shunt that connects the umbilical vein to the inferior vena cava and it can be diagnosed incidentally or in subjects suffering from hepatic encephalopathy, hypoxemia or hypoglycaemia. Sometimes it can be found in patients with cardiac defects or hypoxia caused by pulmonary arteriovenous shunting.Case presentationA 34-year-old male patient was referred to our medical centre for further evaluation of abdominal pain and moderate exertional dyspnoea. An exercise stress echocardiogram was performed in order to understand the mechanism of the exertional dyspnoea. The test was interrupted due to dyspnoea and desaturation and an estimated pulmonary pressure value of 65 mmHg was detected. Exercise pulmonary hypertension (PH) seems to represent the hemodynamic manifestation of early pulmonary vascular disease, acting as a possible transitional phase anticipating resting PH.An MRI of the abdomen showed the presence of a portosystemic shunt from a patent ductus venosus, associated with stenosis of the celiac tripod artery. A CT scan, of the pulmonary circulation, showed a normal pulmonary venous return,mediastinal vessel a normal pulmonary artery. Subsequently, taking into consideration the large size (> 25 mm) of the duct, treatment (closure) of the patent ductus venosus with the help of a detachable vascular plug device was not feasible and open surgery rather than a percutaneous invasive approach would be advisable.ConclusionPersistent ductus venous can lead to pulmonary arteriovenous shunt fistula and exercise related pulmonary hypertension. Percutaneous or surgical closure requires detailed planning and an anatomical and physiological evaluations.

Pulmonary arteriovenous shunt - a rare cause of recurrent stroke due to paradoxical embolism

Paradoxical embolism is one of the mechanisms of ischemic stroke in patients younger than 45 years of age, due to opening between the right and left chambers of the heart through a patent foramen ovale, an atrial or ventricular septal defect, pulmonary arteriovenous malformations (PAVMs), etc. The PAVMs are structurally abnormal vessels that provide direct capillary-free communication between the pulmonary and systemic circulations, and hence an anatomic "right-to-left" shunt. Most pulmonary malformations are congenital and associated with hereditary hemorrhagic telangiectasia (Rendu-Osler-Weber disease). This publication highlights the issues of pathogenesis, clinical presentation, diagnosis and treatment of this pathology, and also describes a clinical case in which multiple PAVMs caused repeated ischemic strokes.

Congenital portosystemic shunts: diagnosis and treatment.

Congenital portosystemic shunts (CPSS) are rare vascular malformations that create an abnormal connection between portal and systemic veins resulting in complete or partial diversion of the portal flow away from the liver to the systemic venous system. Different anatomic types exist and several classifications have been proposed. They can be associated with other malformations especially cardiac and heterotaxia. The main complications include hepatic encephalopathy, liver tumors, portopulmonary hypertension, and pulmonary arteriovenous shunts. Diagnosis relies on imaging, and prenatal diagnosis is possible. Spontaneous closure of the CPSS is possible in some anatomic forms during the first year of life. When the CPSS remains patent, radiologic or surgical closure of the CPSS may prevent, resolve, or stabilize complications. Interventional radiology plays a key role for both the preoperative evaluation with occlusion test to assess the exact anatomy and to measure portal pressure after occlusion of the CPSS. Endovascular closure is the first option for treatment when possible.

Air in the Left Ventricle

A 79-year-old man was admitted with diagnosis of septicemia. During his week-long stay in the hospital, he was treated with parenteral antibiotics and other supportive care with which he improved clinically and was to be discharged. However, he developed acute onset breathlessness followed by hemodynamic collapse and cardiorespiratory arrest. Cardio pulmonary resuscitation was initiated, and he was successfully resuscitated. Urgent bedside echocardiography revealed air in the left atrium (LA) and left ventricle. Color Doppler and contrast echocardiography failed to demonstrate any intracardiac or pulmonary arteriovenous shunt. Central venous (CV) line was removed just before discharge and the procedure was performed at siting posture probably with open hub of CV catheter. Hence, we assume large amount of air must have been entered into the venous circulation and passed across the pulmonary capillary bed into the left heart. Paradoxical air embolism to LA and ventricle is well known, where air enters into the venous circulation at a very rapid rate and exceeds the maximum volume of air that the pulmonary vasculature can filter.

Bevacizumab as a treatment for hereditary hemorrhagic telangiectasia in children: a case report

Five-year-old female patient with hereditary hemorrhagic telangiectasia. Deterioration of cardiopulmonary function with higher oxygen requirements secondary to pulmonary arteriovenous shunts, epistaxis. The patient was treated with the monoclonal antibody bevacizumab, which inhibits the vascular endothelial growth factor, with good clinical outcome. Hereditary hemorrhagic telangiectasia is an autosomal dominant disorder characterized by arteriovenous malformations in different organs, making its clinical presentations varied. Systemic therapeutic options for a generalized disease are limited. The monoclonal antibody bevacizumab, seems to be a good option in this disorder. Although reported as successful in adult population, its use in pediatric population has not yet been reported. Here we report the use of bevacizumab in a 5-year-old female patient with hereditary hemorrhagic telangiectasia, showing clinical benefits and good outcome.

Platypnea-Orthodeoxia Syndrome With Atrial Septal Defect and Ectatic Aortic Root: A Case Report and Review of the Literature

Platypnea-orthodeoxia syndrome (POS) is a rare and underdiagnosed disease characterized by dyspnea in the upright position (platypnea) with simultaneous hypoxemia (orthodeoxia) that is relieved by recumbency. The physiopathological mechanisms involved are mediated by intracardiac shunts, pulmonary arteriovenous shunts or ventilation/perfusion mismatch. When POS is caused by a cardiac pathology, there is an anatomical (interatrial communication) and a functional component (as a dilated aorta or pneumectomy) working together to cause a right to left shunt without a constant right to left pressure gradient. Diagnosis is suspected through pulse oximetry verifying orthodeoxia. Confirmation usually is made by transesophageal echocardiography with bubble study to visualize the shunt. Percutaneous closure of the shunt is effective in most cases of cardiac POS. We report a case of an 87-year-old woman with POS related to a patent foramen ovale and an ectatic aorta followed by a review of the literature. J Med Cases. 2016;7(2):54-57 doi: http://dx.doi.org/10.14740/jmc2414w

Platypnea-Orthodeoxia Syndrome With Atrial Septal Defect and Ectatic Aortic Root: A Case Report and Review of the Literature

Platypnea-orthodeoxia syndrome (POS) is a rare and underdiagnosed disease characterized by dyspnea in the upright position (platypnea) with simultaneous hypoxemia (orthodeoxia) that is relieved by recumbency. The physiopathological mechanisms involved are mediated by intracardiac shunts, pulmonary arteriovenous shunts or ventilation/perfusion mismatch. When POS is caused by a cardiac pathology, there is an anatomical (interatrial communication) and a functional component (as a dilated aorta or pneumectomy) working together to cause a right to left shunt without a constant right to left pressure gradient. Diagnosis is suspected through pulse oximetry verifying orthodeoxia. Confirmation usually is made by transesophageal echocardiography with bubble study to visualize the shunt. Percutaneous closure of the shunt is effective in most cases of cardiac POS. We report a case of an 87-year-old woman with POS related to a patent foramen ovale and an ectatic aorta followed by a review of the literature. J Med Cases. 2016;7(2):54-57 doi: http://dx.doi.org/10.14740/jmc2414w

Brain abscess associated with patent foramen ovale.

Brain abscesses can develop with Tetralogy of Fallot and pulmonary anterior venous fistula with large right-to-left shunt. However, some patients exhibit cryptogenic brain abscess (CBA) in the absence of any such congenital disease or other infections. Patent foramen ovale (PFO) is a very common disease that exhibits right-to-left shunt. This study reports the potential for concern between CBA and PFO. We enrolled patients with CBA in our hospital between January 2003 and January 2013. Patients underwent transesophageal echocardiography (TEE) with contrast medium to investigate the presence of PFO. Seven patients were included. Four were females, and the mean age was 67.7 ± 9.2 years. In all patients, TEE failed to reveal any new findings, however, six patients had PFO, and another patient had pulmonary arteriovenous shunt. Four patients had odontopathy. In this study, all CBA patients exhibited right-to-left shunt. CBA might be caused by paradoxical embolization of a bacterial mass via PFO. Thus, more patients with CBA need to undergo TEE to detect PFO.

Critical care strategies to improve neurocognitive outcome in thoracic surgery

This review focuses on neurocognitive outcome with respect to potential pathophysiological inflammatory mechanisms of thoracic surgery and one-lung ventilation, risk factors of postoperative delirium and postoperative cognitive dysfunction (POCD) as well as anti-inflammatory strategies. Neurocognitive dysfunction is associated with increased mortality and disability. The incidence of postoperative delirium and POCD is often underestimated in the perioperative care setting. Both are threatening complications after major surgery and independently associated with an increased morbidity and mortality. Nevertheless, in thoracic surgery, the clinical relevance of neurocognitive dysfunction is still underestimated. Currently, there has been a growing interest in inflammation as a cause of the pathogenesis of postoperative delirium and POCD. Furthermore, thoracic surgery often requires one-lung ventilation, which is accompanied with important physiological disturbances, and leads to a pulmonary arteriovenous shunt with the decrease of arterial oxygen content and an exaggerated activation of inflammatory processes. As inflammation is involved in brain dysfunction, anti-inflammatory strategies in the perioperative setting seem to be potential neuroprotective targets concerning specially high-risk patients undergoing thoracic surgery under one-lung ventilation. There is evidence that important key strategies improve neurocognitive outcome after thoracic surgery. This includes adequate risk stratification, the anesthetic management and postoperative critical care strategies.

An Unusual Case of Cyanosis in a Young Boy

Question: A 13-year-old boy presented with a 2.5-year history of dyspnea and fatigue and detected to have cyanosis over the past 6 months. He did not have any history of palpitations, syncope, cough, wheezing, or recurrent chest infections. He was the elder of 2 siblings, born out of a nonconsanguineous marriage with a normal, uncomplicated antenatal and perinatal history. His developmental history and performance at school were normal. His clinical examination revealed normal anthropometric parameters as per his age, cyanosis at rest, and grade III clubbing of fingers; the rest of his systemic examination including cardiovascular, pulmonary, neurologic, and abdominal examination was normal. Arterial blood gas analysis revealed type 1 respiratory failure, mild respiratory alkalosis, and severe hypoxemia (pH, 7.46; PO2 on room air, 49 mmHg; PCO2, 32.9 mmHg; HCO3, 23.1 mmol/L; SpO2, 88%). Chest xray was normal. Air contrast-enhanced transthoracic echocardiography revealed right-to-left shunting evident by the appearance of air bubbles in the left cardiac chambers about 3 cardiac beats after appearance in the right chambers but no structural cardiac defect or pulmonary hypertension. Compute tomographic angiography of the chest was normal and did not reveal any large pulmonary arteriovenous shunt. So with the possibility of multiple small intrapulmonary shunts he was further evaluated for any hepatoportal disease. Liver function tests and arterial plasma ammonia levels were normal; upper gastrointestinal endoscopy was normal. Doppler ultrasonography of the hepatoportal system (Figure A), contrast magnetic resonance imaging of the abdomen (Figure B, C) were done for further evaluation which revealed an abnormal vascular channel in the liver (arrow) and barely visible intrahepatic portal venous radicals (IHPVR; asterisk). What is the most likely diagnosis? See the GASTROENTEROLOGY web site (www.gastrojournal.org) for more information on submitting your favorite image to Clinical Challenges and Images in GI.

Cerebral iodized lipid embolization via a pulmonary arteriovenous shunt: rare complication of transcatheter arterial embolization for hepatocellular carcinoma

We report the first European case of cerebral iodized lipid embolism post transcatheter arterial embolization for hepatocellular carcinoma. Lipiodol emboli and corresponding multifocal brain ischemia were documented with computed tomography (CT) and magnetic resonance (MR) in the acutely symptomatic patient. Transcranial Doppler sonography with contrast indicated a right-to-left shunt, while on a follow-up CT scan lipiodol embolization was detected in both lungs. Dilated pulmonary vessels and thick vascular channels were seen in the vicinity of the right diaphragm suggestive of pulmonary arteriovenous shunt. The patient symptoms regressed with supportive care alone, but he died 5 months later due to hepatic failure unrelated to the procedure.

Normal and abnormal pulmonary arteriovenous shunting: occurrence and mechanisms

Severe cyanosis due to pulmonary arteriovenous fistulas occurs often after a bidirectional superior cavopulmonary anastomosis (Glenn operation) and also in some congenital anomalies in which hepatic venous blood bypasses the lungs in the first passage. Relocation of hepatic flow into the lungs usually causes these fistulas to disappear. Similar pulmonary arteriovenous fistulas are observed in hereditary haemorrhagic telangiectasia, and in liver disease (hepatopulmonary syndrome). There is no convincing identification yet of a responsible hepatic factor that produces these lesions. Candidates for such a factor are reviewed, and the possibility of angiotensin or bradykinin contributing to the fistulas is discussed.

Usefulness of Transnasal Argon Plasma Coagulation for Esophageal Varices Compared with the Peroral Method: A Randomized and Prospective Clinical Study

Background: Argon plasma coagulation (APC) is very useful as a consolidation treatment for reducing the recurrence of esophageal varices (EVs). However, repeated sedation in endoscopic treatment has the risk of prolonging hepatic encephalopathy and affects the respiratory state of liver cirrhosis (LC) patients, in whom pulmonary arteriovenous shunts are observed. We evaluated prospectively whether transnasal endoscopic APC without sedation is more effective than peroral endoscopic APC with sedation. Patients and Methods: LC patients (n = 101), treated by endoscopic injection sclerotherapy to eradicate EVs, were randomly divided into a transnasal APC group (n = 50) and a peroral APC group (n = 51). The primary efficacy endpoint was the cumulative recurrence rate of EVs. The secondary endpoints were blood pressure (BP), heart rate, oxygen saturation during APC and complications. Results: There was no significant difference in the cumulative recurrence rate of EVs at 36 months between the transnasal APC and peroral APC groups (35.0 vs. 40.8%, p = 0.39, log-rank test), indicating that transnasal APC is not inferior to peroral APC. The transnasal APC group showed more stable intraoperative BP and oxygen saturation values, and a lower incidence of epigastralgia (56.0 vs. 74.5%, p = 0.04). Conclusion: The efficacy of reducing the recurrence of EVs in the transnasal APC group was not significantly different from that in the peroral APC group. Transnasal APC caused less distress and required no sedation. Therefore, this method was more advantageous for LC patients at risk of suffering from prolongation of hepatic encephalopathy.

Lessons from liver transplantation

Lessons from liver transplantation

Liver Transplantation for Cardiac Failure from Hereditary Hemorrhagic Telangiectasia

Purpose: 44-years-of-age Hispanic woman presented to the hospital with palpitations, dyspnea, and hematochezia. She had a ten-year history of HHT manifested initially as repeated episodes of epistaxis and lower gastrointestinal bleeding. Examination revealed pallor, multiple telangiectasiae of the oral cavity, finger tips and upper back. A colonoscopy revealed multiple colonic telangiectasiae, which were cauterized during the procedure. Computerized tomography of the liver showed moderately enlarged liver without any stigmata of portal hypertension. There was substantial diffuse shunting between the hepatic arteries to hepatic vein. The portal venous system was of normal caliber without splenomegaly. The left hepatic artery from the celiac axis and the right hepatic artery from the superior mesenteric artery were massively enlarged and most of the flow occurred through the left hepatic artery. Chest X-ray showed right pleural effusion. Echocardiogram revealed flattening of the inter ventricular septum with mild abnormal motion secondary to rightsided pressure overload, severe tricuspid regurgitation with moderate pulmonary hypertension with a PA systolic pressure of 58 mmHg. A right heart catheterization showed cardiac output of 9.05 L/min and cardiac index of 5.79 L/min/m2. A pulmonary arteriogram detected prominent pulmonary arteries and pulmonary veins without significant pulmonary arteriovenous malformations or shunting. Her dyspnea was attributed to the cardiac failure secondary to the massive arterio-venous shunting in the patient's liver. She underwent OLT in December 2010. The patient received one unit of blood and two units of cell saver. The cold ischemia time was 8.5 hrs. Her recovery was uneventful and she is doing quite well through her fifth month after the liver transplant. Discussion: HHT is an autosomal dominant disorder characterized by angiodysplastic lesions involving various organs. Hepatic involvement is observed in 30% cases. Increased sinusoidal blood flow can lead to increased deposition of fibrous tissue and “arterialization” of the portal vein. Liver undergoes nodular transformation, with regenerative nodules that compress the surrounding liver parenchyma without the fibrous septae, thus known as pseudocirrhosis. AV shunts may cause hypo perfusion of the peribiliary plexus and ischemic necrosis of bile ducts with development of biliary stricture. Cardiovascular symptoms occur when intrahepatic shunt is more than 20% of cardiac output. OLT has gained popularity over embolization. Intraoperative bleeding and technically demanding due to the collateral arterial reorganization can be challenging. Thrombosis and reappearance of AV malformations can occur in the long run.

Microemboli may link spreading depression, migraine aura, and patent foramen ovale.

Patent foramen ovale and pulmonary arteriovenous shunts are associated with serious complications such as cerebral emboli, stroke, and migraine with aura. The pathophysiological mechanisms that link these conditions are unknown. We aimed to establish a mechanism linking microembolization to migraine aura in an experimental animal model. We introduced particulate or air microemboli into the carotid circulation in mice to determine whether transient microvascular occlusion, insufficient to cause infarcts, triggered cortical spreading depression (CSD), a propagating slow depolarization that underlies migraine aura. Air microemboli reliably triggered CSD without causing infarction. Polystyrene microspheres (10 microm) or cholesterol crystals (<70 microm) triggered CSD in 16 of 28 mice, with 60% of the mice (40% of those with CSD) showing no infarcts or inflammation on detailed histological analysis of serial brain sections. No evidence of injury was detected on magnetic resonance imaging examination (9.4T; T2 weighted) in 14 of 15 selected animals. The occurrence of CSD appeared to be related to the magnitude and duration of flow reduction, with a triggering mechanism that depended on decreased brain perfusion but not sustained tissue damage. In a mouse model, microemboli triggered CSD, often without causing microinfarction. Paradoxical embolization then may link cardiac and extracardiac right-to-left shunts to migraine aura. If translatable to humans, a subset of migraine auras may belong to a spectrum of hypoperfusion disorders along with transient ischemic attacks and silent infarcts.

Congenital extrahepatic portosystemic shunt associated with heterotaxy and polysplenia

Heterotaxy with polysplenia is associated with many cardiovascular anomalies including the occasional occurrence of congenital extrahepatic portosystemic shunts (CEPS). Missing this anomaly can lead to inappropriate and ineffective therapy. To emphasize the importance and associated anatomy of CEPS in conjunction with heterotaxy with polysplenia. Review of three young children who presented with cyanosis and pulmonary hypertension without a cardiac etiology. They were known (1) or discovered (2) to have heterotaxy with polysplenia. There was absence of the intrahepatic inferior vena cava (IVC) with azygos or hemiazygos continuation in all three cases. In spite of normal liver function, they were discovered to have large portosystemic shunts, splenorenal in location, along with diffuse peripheral pulmonary arterial dilatation suggestive of CEPS (Abernethy malformation) with hepatopulmonary or, more accurately, portopulmonary syndrome. All CEPS were ipsilateral to the spleens. Patency of the portal veins in these cases allowed for percutaneous shunt closure with resolution of cyanosis. CEPS is associated with heterotaxy with polysplenia and can be symptomatic because of pulmonary arteriovenous (AV) shunting. Portal and hepatic vein patency are critical for determining feasibility of CEPS closure.

Hypergalactosemia in early infancy: Diagnostic strategy with an emphasis on imaging

Portosystemic shunt is one of the main causes of persistent hypergalactosemia without enzyme deficiency, but the diagnostic imaging strategy has not yet been established. The purpose of the present study was to establish a diagnostic imaging strategy. A retrospective investigation of the clinical and imaging findings of 10 children with persistent hypergalactosemia without enzyme deficiency detected by screening was undertaken. Abnormal ultrasonography (US) findings were detected in all eight patients with liver disorders. In three patients with citrin deficiency, the combination of fatty liver on US and laboratory evidence of cholestasis led to the diagnosis. In three patients with portosystemic shunt, US on sedation clearly depicted the shunt vessels. The extent was more easily understood on contrast computed tomography (CT). Per-rectal portal scintigraphy with N-isopropyl-p-I-123 iodoamphetamine and lung perfusion scintigraphy with (99m)Tc macroaggregated albumin were useful for evaluation of portal shunt index and assessment of pulmonary arteriovenous shunt. One patient underwent transarterial coil embolization. In two patients with hepatic tumor, the lesions and its vascularity were clearly demonstrated on US and dynamic CT. In one patient, small shunt index on per-rectal portal scintigraphy suggested no need for treatment. The other patient was treated with a combination of steroid, radiation, and interventional radiology. The etiology remained unknown in two children. In the assessment of hypergalactosemia, US is the modality of choice. CT is a useful tool for more detailed evaluation of the abnormalities found on US. Per-rectal portal scintigraphy and pulmonary perfusion scintigraphy play an important role in the evaluation of portosystemic shunt. Interventional radiology is sometimes effective.