Congenital Cardiac Anesthesia Society
A Section of the the Society for Pediatric Anesthesia

{“questions”:{“ue4cq”:{“id”:”ue4cq”,”mediaType”:”image”,”answerType”:”text”,”imageCredit”:””,”image”:””,”imageId”:””,”video”:””,”imagePlaceholder”:””,”imagePlaceholderId”:””,”title”:”Author: Krupa Desai, MD \u2013 Children\u2019s Hospital of Philadelphia; Chinwe Unegbu, MD \u2013 Children\u2019s National Hospital\r\n\r\nA 3 year-old-child with hypoplastic left heart syndrome (HLHS) status post hybrid palliation and subsequent comprehensive stage II repair presents for cardiac magnetic resonance imaging (MRI). The imaging cardiologist plans to utilize ferumoxytol instead of gadolinium contrast. Which of the following is the MOST LIKELY indication for ferumoxytol contrast versus gadolinium contrast? \r\n”,”desc”:””,”hint”:””,”answers”:{“8olpx”:{“id”:”8olpx”,”image”:””,”imageId”:””,”title”:”A. Iron overload secondary to frequent blood transfusions “},”ck6ku”:{“id”:”ck6ku”,”image”:””,”imageId”:””,”title”:”B. History of anaphylaxis to amoxicillin “},”t7eag”:{“id”:”t7eag”,”image”:””,”imageId”:””,”title”:”C. High resolution imaging of aortopulmonary collaterals “,”isCorrect”:”1″},”k18ov”:{“id”:”k18ov”,”image”:””,”imageId”:””,”title”:”D. Liver dysfunction”}}}},”results”:{“vylzp”:{“id”:”vylzp”,”title”:””,”image”:””,”imageId”:””,”min”:”0″,”max”:”1″,”desc”:”Ferumoxytol (Feraheme, AMAG Pharmaceuticals, Waltham, MA) is an intravenous formulation of enteral iron classically used to treat severe iron deficiency anemia in adult patients with chronic kidney disease. Ferumoxytol has been shown to be an effective and safe magnetic resonance imaging (MRI) contrast agent. Ferumoxytol allows for contrast enhanced imaging in patients with contraindications to gadolinium-based contrast agents (GBCA), such as renal failure. Ferumoxytol has recently been used with increasing frequency in smaller and more medically fragile children. \r\n\r\nDue to the long half-life, ferumoxytol does not have to be administered during the cardiac MRI exam itself. Rather, it can be administered hours prior to the cardiac MRI. This is particularly beneficial in tenuous cardiac patients in order to decrease the time spent outside of the intensive care unit (ICU) by administration of ferumoxytol at bedside prior to transport. Ferumoxytol is impermeable to vascular capillaries and is not filtered by the kidneys. Thus, it remains in the intravascular compartment until it is ingested by macrophages and then excreted by the liver. Due to its large molecular size and dextran coat, ferumoxytol has a long intravascular half-life of approximately 14\u201315 hours, which provides a long and stable time window for vascular enhancement and imaging. As the uptake and metabolism of ferumoxytol is by the reticuloendothelial system, the risk of nephrogenic systemic fibrosis and central nervous system deposition is nil compared to GBCA. \r\n\r\nIn pediatric patients, the additional benefits of ferumoxytol are quite noteworthy. Ferumoxytol allows for patients with renal dysfunction to have contrast-enhanced MRI imaging when needed due to a lack of renal metabolism and excretion. Administration of ferumoxytol is quite beneficial in patients with cardiac lesions whose residual disease burden can be best addressed by contrast enhanced imaging. This includes patients with Fontan physiology, anomalous coronaries, and those with aortopulmonary collaterals. Use of ferumoxytol negates the need for suspended respirations during cardiac MRI studies due to prolonged vascular enhancement. Suspended respirations are typically requested to obtain better-quality imaging with GBCA and to minimize motion artifact related to respiratory efforts. As a result, patients undergoing cardiac MRI with GBCA are more likely to be intubated and receive neuromuscular blocking agents to facilitate suspended respirations during MRI gating. Imaging parameters are enhanced with the use of ferumoxytol negating the need for respiratory pauses. Ultimately, this results in a reduced time needed for the cardiac MRI imaging and general anesthesia when compared to imaging obtained with GBCA. \r\n\r\nFerumoxytol has an excellent safety profile with a long history of use. Due to its long half-life, however, anaphylactic reactions (0.03% aggregate rate in post-market surveillance of > 8000 administrations) can be serious and difficult to treat. The majority of anaphylactic reactions are recognizable within 5 minutes of starting the infusion. Thirty percent of individuals who develop anaphylatic reactions have had at least one prior allergic reaction to a medication. Due to the long half-life of ferumoxytol, some consider a history of anaphylaxis to any other medication a \u201csoft\u201d contraindication to ferumoxytol. Hypersensitivity reactions resulting in hypotension and death have been reported with the use of ferumoxytol for the treatment of anemia in adults. The reports of hypersensitivity to ferumoxytol in adults led to a black box warning in 2015 by the Food and Drug Administration (FDA). Monitoring for signs of anaphylaxis (hypotension, erythema, rash, bronchospasm, etc.) is prudent. Blood pressure measurements should be performed routinely up until 30 min after completion of the infusion. Early treatment with diphenhydramine and epinephrine has successfully treated anaphylaxis. \r\n\r\nHypotension alone (nonimmunologic) has also been associated with ferumoxytol and is thought to be related to the release of free iron. Other intravenous iron formulations have similar effects on blood pressure (hypotension). As a result, the FDA has recommended dilution and slow administration of ferumoxytol over approximately 15 minutes. \r\n\r\nFerumoxytol is contraindicated in patients with a history of allergic reactions to ferumoxytol or other intravenous iron products and those with iron overload such as hemochromatosis, severe chronic hemolysis, frequent blood transfusion, and prolonged hemodialysis. Additionally, use is cautioned in patients with severe hepatic disease. \r\n\r\nAll MRI images may be altered by ferumoxytol for days to months. This complicates subsequent MRI imaging of other areas of the body such as the brain. As a result, close coordination and communication is needed with respect to the sequence of imaging in patients requiring MRI scans of other regions of the body in addition to the cardiac MRI. \r\n\r\nReferences\r\n1.\tRuangwattanapaisarn N, Hsiao A, Vasanawala SS. Ferumoxytol as an off-label contrast agent in body 3T MR angiography: a pilot study in children. Pediatr Radiol<\/em>. 2015; 45(6): 831-839. doi:10.1007\/s00247-014-3226-3.2. \r\n2.\tCorot C, Robert P, Idee J, Port M. Recent advances in iron oxide nanocrystal technology for medical imaging. Adv Drug Deliv Rev<\/em>. 2006; 58(14): 1471-1504. doi:10.1016\/j.addr.2006.09.013 \r\n3.\tNguyen KL, Yoshida T, Han F, et al. MRI with ferumoxytol: A single center experience of safety across the age spectrum. J Magn Reson Imaging<\/em>. 2017; 45(3): 804-812. doi:10.1002\/jmri.25412. \r\n4.\tVan Wyck DB. Labile iron: manifestations and clinical implications. J Am Soc Nephrol<\/em> 2004; 15: S107\u2013S111. \r\n5.\tWise-Faberowski L, Velasquez N, Chan F, Vasanawala S, McElhinney DB, Ramamoorthy C. Safety of ferumoxytol in children undergoing cardiac MRI under general anaesthesia. Cardiol Young<\/em>. 2018; 28(7): 916-921. doi:10.1017\/S1047951118000306 \r\n6.\tLi W, Tutton S, Vu AT, et al. First-pass contrast-enhanced magnetic resonance angiography in humans using ferumoxytol, a novel ultrasmall superparamagnetic iron. (USPIO)-based blood pool agent. J Magn Reson Imaging<\/em>. 2005; 21: 46\u201352. \r\n7.\tRampton D, Folkersen J, Fishbane S, et al. Hypersensitivity reactions to intravenous iron: guidance for risk minimization and management. Haematologica<\/em>. 2014; 99: 1671\u20131676.\r\n”,”redirect_url”:””}}}

{“questions”:{“9reae”:{“id”:”9reae”,”mediaType”:”image”,”answerType”:”text”,”imageCredit”:””,”image”:””,”imageId”:””,”video”:””,”imagePlaceholder”:””,”imagePlaceholderId”:””,”title”:”Author: Krupa Desai, MD \u2013 Children\u2019s Hospital of Philadelphia; Chinwe Unegbu, MD \u2013 Children\u2019s National Hospital\r\n\r\nA three-year-old child with an atrial septal defect (ASD) presents for possible transcatheter ASD device closure. The interventional cardiologist plans on using intracardiac echocardiography (ICE) rather than transesophageal echocardiography (TEE). What represents the MOST LIKELY reason that ICE would be utilized for this procedure?\r\n”,”desc”:””,”hint”:””,”answers”:{“qolo7”:{“id”:”qolo7″,”image”:””,”imageId”:””,”title”:”A. Reduced cost versus TEE”},”zo55a”:{“id”:”zo55a”,”image”:””,”imageId”:””,”title”:”B. Provides a more comprehensive examination versus TEE”},”1w3pl”:{“id”:”1w3pl”,”image”:””,”imageId”:””,”title”:”C. Ability to be performed by the interventional cardiologist”,”isCorrect”:”1″},”ociq6″:{“id”:”ociq6″,”image”:””,”imageId”:””,”title”:”D. Reduced risk of vascular injury”}}}},”results”:{“29egv”:{“id”:”29egv”,”title”:””,”image”:””,”imageId”:””,”min”:”0″,”max”:”1″,”desc”:”Transcatheter closure of an ASD represents a safe and effective alternative to surgical closure. Traditionally, imaging via transesophageal echocardiography (TEE) has been utilized to guide ASD closure. TEE has a well-established role in guiding interventional procedures due to its ability to provide real-time 3D imaging and superior image resolution when compared to transthoracic echocardiography. However, intracardiac echocardiography (ICE) is being used with increasing frequency and is replacing TEE as the primary imaging technique utilized to guide device closure of ASDs. \r\n\r\nICE is a unique imaging modality in that it can provide high-resolution real-time visualization of cardiac structures. ICE is typically performed with a catheter that is inserted through a venous sheath placed by the interventional cardiologist. The ICE catheter has an ultrasound transducer at its tip that emits sound waves to produce images of the heart. ICE allows for continuous monitoring of catheter location within the heart during a cardiac catheterization or electrophysiology study. As a result, early recognition of procedural complications, such as pericardial effusion or thrombus formation is possible. Additional benefits of ICE are excellent patient tolerance, reduction of fluoroscopy time, and lack of need for a second operator to acquire echocardiography images. In certain cases, general endotracheal anesthesia may be avoided if ICE is used instead of TEE, especially in adults. In the adult population, ICE has largely replaced TEE as the ideal imaging modality used to guide certain procedures, such as atrial septal defect closure and catheter ablation of cardiac arrhythmias. For adult electrophysiology studies, ICE has been widely adopted to guide transseptal punctures due to its ability to define atrial septal anatomy and provide visualization of transseptal catheter position in relation to other structures within the heart. ICE also has an emerging role in other catheter-based interventions. \r\n\r\nBoth TEE and ICE have inherent strengths and weakness (see Table 1) that should be considered prior to deciding on the optimal imaging modality for a given procedure. ICE can be performed by the interventional cardiologist; therefore, a second operator isn\u2019t needed for image acquisition. In pediatric centers that perform cardiac catheterization without intubation, ICE negates the need for a general endotracheal anesthetic. However, many institutions still perform general endotracheal anesthesia (GETA) for pediatric cardiac catheterizations. Therefore, the potential cost savings and patient comfort attributed to utilizing ICE may not be realized at those centers. Additionally, ICE generates images from within the heart at short distances with high spatial resolution. A critical role of ICE in the interventional cardiac catheterization lab is the early recognition of procedural complications. ICE allows for immediate assessment and differentiation of possible causes of hemodynamic compromise. Pericardial effusion is a serious complication of interventional cardiac catheterization procedures. ICE allows detection of pericardial effusion before the occurrence of hemodynamic changes.\r\n\r\nPerceived disadvantages of ICE include the high upfront cost of the single-use catheters. There is also lower spatial resolution and image quality of far-field structures (from the right atrium) such as the pulmonary veins and left atrial appendage. Additionally, there is increased risk of vascular injury with insertion of the ICE catheter. Another major criticism of ICE is the limited number of published studies supporting its use in small children. Many published studies are either in adults or larger children. A study published by Patel et al in 2006 did demonstrate safety and efficacy of ICE to guide ASD device closure in patients smaller than 15 kg. Nonetheless, this remains an area of significant debate. \r\n\r\nWhen compared to ICE, TEE has the advantage of lower upfront cost and does not require venous or arterial access thereby limiting vascular access-site complications. TEE also allows for more comprehensive cardiac imaging than with a full three dimensional (3D) evaluation. A known drawback with TEE is that it often requires GETA to facilitate placement of the TEE probe. Additionally, there is the chance for probe related trauma. Unlike ICE, which can be operated and interpreted by the interventional cardiologist, TEE requires an imaging echocardiographer. It is important to highlight that when necessary, both TEE and ICE, can be used in a complementary fashion. TEE can be used for initial evaluation and planning for ASD closure, and procedural ICE can provide additional guidance for device size selection and positioning. \r\n\r\n \r\n\r\nReferences\r\n1.\tHijazi ZM, Wangt Z, Cao Q, et al. Transcatheter closure of atrial septal defects and patent foramen ovale under intracardiac echocardiographic guidance. Catheter Cardiovasc Interv<\/em>. 2001; 52: 194\u2013199.\r\n2.\tEnriquez A, Saenz L, Rosso R, et al. Use of Intracardiac Echocardiography in Interventional Cardiology: Working with the Anatomy Rather Than Fighting It. Circulation<\/em>. 2018; 137: 2278\u20132294. \r\n3.\tAlqahtani F, Bhirud A, Aljohani S, et al. Intracardiac versus transesophageal echocardiography to guide transcatheter closure of interatrial communications: Nationwide trend and comparative analysis. J Interv Cardiol<\/em>. 2017; 30: 234-241.\r\n4.\tBasman C, Parmar Y, Kronzon I. Intracardiac Echocardiography for Structural Heart and Electrophysiological Interventions. Curr Cardiol Rep<\/em>. 2017; 19: 102. \r\n5.\tAssaidi A, Sumian M, Mauri L, et al. Transcatheter closure of complex atrial septal defects is efficient under intracardiac echocardiographic guidance. Arch Cardiovasc Dis<\/em>. 2014; 107: 646-653. \r\n6.\tZanchetta M, Onorato E, Rigatelli G, et al. Intracardiac echocardiography-guided transcatheter closure of secundum atrial septal defect: A new efficient device selection method. J Am Coll Cardiol<\/em>. 2003; 42: 1677\u20131682.\r\n7.\tPatel A, Cao QL, Koenig P, Hijazi Z. Intracardiac echocardiography to guide closure of atrial septal defects in children less than 15 kilograms. Catheter and Cardiovasc Interv<\/em>. 2006; 68: 287-291. \r\n\r\n”,”redirect_url”:””}}}

{“questions”:{“1df20”:{“id”:”1df20″,”mediaType”:”image”,”answerType”:”text”,”imageCredit”:””,”image”:””,”imageId”:””,”video”:””,”imagePlaceholder”:””,”imagePlaceholderId”:””,”title”:”Author: Krupa Desai, MD \u2013 Children\u2019s Hospital of Philadelphia; Chinwe Unegbu, MD \u2013 Children\u2019s National Hospital\r\n\r\nA 14 year old male with Pulmonary Arterial Hypertension secondary to pulmonary venoocclusive disease managed with treprostinil, ambrisentan, and milrinone presents with increasing dyspnea. A transthoracic echocardiogram (TTE) demonstrates suprasystemic right ventricular (RV) systolic pressures, moderately decreased RV function, severe RV dilation, and moderate tricuspid regurgitation. What is the MOST APPROPRIATE treatment? \r\n”,”desc”:””,”hint”:””,”answers”:{“ei2nd”:{“id”:”ei2nd”,”image”:””,”imageId”:””,”title”:”A. Start epoprostenol”},”mdhsi”:{“id”:”mdhsi”,”image”:””,”imageId”:””,”title”:”B. Perform a balloon atrial septostomy (BAS) “},”hs7bc”:{“id”:”hs7bc”,”image”:””,”imageId”:””,”title”:”C. Placement of a Potts shunt”,”isCorrect”:”1″},”w9rgc”:{“id”:”w9rgc”,”image”:””,”imageId”:””,”title”:”D. Start inhaled nitric oxide”}}}},”results”:{“yid37”:{“id”:”yid37″,”title”:””,”image”:””,”imageId”:””,”min”:”0″,”max”:”1″,”desc”:”Pulmonary arterial hypertension (PAH) is a rare and progressive disease. Despite advances in medical therapy, there is significant morbidity and mortality associated with this disease. Patients with PAH often have elevations in pulmonary vascular resistance (PVR) because of pulmonary vascular bed remodeling. As this disease naturally progresses, the physiologic sequelae are increased PVR followed by right ventricular (RV) hypertrophy, RV dysfunction, and ultimately death. \r\n\r\nPulmonary veno-occlusive disease (PVOD) falls into a rare category of PAH and is caused by remodeling of the pulmonary venules with hallmark obliteration of the small pulmonary veins. The diagnosis of PAH secondary to PVOD carries a poor prognosis. In patients with PVOD, severe\/life-threatening pulmonary edema can occur with the initiation of any class of pulmonary vasodilators. To date, strong evidence of the beneficial effect of pulmonary vasodilator therapy in patients with PVOD is lacking. \r\n\r\n\r\nThe goal of medical therapy in patients with PAH is to dilate the pulmonary vascular bed, reverse vascular remodeling, and restore endothelial function. The common treatment modalities target specific pathways involved in PAH pathogenesis: the prostacyclin, endothelin-1, and nitric oxide pathways to achieve these goals. This patient is on treprostinil, ambrisentan, and milrinone. Treprostinil is a prostacyclin analogue commonly administered to patients with PAH via continuous intravenous infusion. Prostacyclin analogues are important pulmonary and systemic vasodilators and patients with PAH often have decreased production of prostacyclins. Epoprostenol and treprostinil are the two most commonly administered prostacyclin analogues. Treprostinil has a longer half-life and greater stability than epoprostenol. \r\n\r\n\r\nEndothelin (ET) is a peptide produced in the kidney with three isoforms – ET-1, ET-2, and ET-3. ET-1 is the predominant isoform and binds to two G-protein-coupled receptors ET_{A<\/sub> and ETB<\/sub>. ETA<\/sub> is the predominate form on vasculature and mediates vasoconstriction. Ambrisentan is a selective ETA<\/sub> receptor antagonist. Patients with PAH have increased levels of circulating ET-1 that bind to ETA<\/sub> to mediate pulmonary arterial vasoconstriction and promote proliferation of pulmonary vascular smooth muscle. Bosentan is a commonly utilized nonselective ETA<\/sub> and ETB<\/sub> receptor antagonist. The renal vascular endothelium expresses the ETB<\/sub> receptor and here ET-1acts in a manner to increase vasodilator secretion. \r\n\r\n\r\nMilrinone is an additional outpatient medical therapy for this patient. Milrinone is a phosphodiesterase type-3 inhibitor that decreases pulmonary vascular resistance via agonism of the nitric oxide\u2013cyclic guanosine monophosphate (NO\u2013cGMP) pathway. In addition to causing pulmonary and systemic vasodilation, milrinone can potentially augment myocardial contractility and lusitropy. \r\n\r\n\r\nUnfortunately despite maximal medical therapy, some patients progress to end-stage PAH and are quite symptomatic. Bilateral lung transplantation is the only definitive therapy that offers the possibility of long term survival, but survival to lung transplantation is low. The Potts shunt and balloon atrial septostomy (BAS) are two palliative procedures that can be used to manage medically refractory PAH. The patient in this scenario is failing medical therapy and is in need of a palliative procedure to reduce afterload on the right ventricle (RV). RV function is an important prognostic indicator in patients with PAH. Many medical therapies aim to reduce right ventricular afterload as a means to improve right ventricular function. \r\n\r\n\r\nOf the options listed, the most appropriate treatment is placement of a Potts shunt, which is a connection from the left pulmonary artery to the descending thoracic aorta. This surgical technique was first described in 1946 by Dr. Willis Potts. It was originally intended to be used in children with Tetralogy of Fallot to provide pulmonary blood flow. In 2004, it was utilized to manage two children with refractory suprasystemic PAH. \r\n\r\n\r\nA Potts shunt should be considered in patients with end stage, medically refractory, suprasystemic pulmonary hypertension. A Potts shunt would serve as a pop off for the right ventricle to reduce RV afterload thereby improving RV systolic function and possibly serving as a bridge to lung transplantation. Current literature demonstrates that the Potts shunt improves hemodynamics, functional status, and transplant-free survival in children with severe PAH. The Potts shunt is also more durable in teenagers and decompresses the right ventricle without causing upper body cyanosis. This shunt sends deoxygenated blood to the lower half of the body while preserving the highest oxygenated blood for the upper half of the body and the brain. \r\n\r\n\r\nA single center retrospective review performed from 2016 to 2019 at Columbia University Medical Center-New York Presbyterian demonstrated 100% survival at 33 months after Potts shunt in 5 pediatric patients with supra-systemic pulmonary arterial hypertension. Further studies are needed to assess long-term survival in patients with a Potts shunt. It is critical to remember that a Potts shunt, in theory, is an unrestrictive communication between the pulmonary and systemic circulations; therefore, its effectiveness lies in reducing right ventricular pressures from suprasystemic to systemic levels. Thus, a shunt placed in a child whose right ventricle cannot generate systemic pressure will prove ineffective. A valved Potts shunt is a modification that allows for unidirectional flow from pulmonary artery to the descending thoracic aorta. This prevents any reversal of flow from the aorta to the pulmonary circulation during diastole. The valved Potts shunt may serve to benefit the child who has systemic right ventricular pressures at rest but suprasystemic pressures with exertion. \r\n\r\n\r\nBalloon atrial septostomy (BAS) is an interventional procedure in which an interatrial orifice is created by needle puncture and dilated with a balloon catheter. Possible contraindications for BAS include: severe RV failure, mean right atrial pressure greater than 20 mmHg, pulmonary vascular resistance index greater than 55U\/m^{2<\/sup>, baseline oxygen saturation less than 90%, and LVEDP greater than 18mmHg. However, these criteria vary based on the center surveyed. Unlike the Potts shunt, which leads to lower extremity deoxygenation, the atrial septostomy leads to global deoxygenation. BAS is not the most appropriate intervention for this patient as studies have shown that BAS does not provide a lasting reduction of pulmonary artery pressure to preserve right ventricular function as does the Potts shunt. A patient with PAH who improves with BAS is often one in whom right ventricular failure is relatively advanced such that the right ventricular end diastolic pressure must be abnormally elevated to generate right-to-left atrial flow. Literature does support an improvement in symptoms after BAS in pediatric patients with subsystemic right ventricular pressure who had experienced syncope. The overall procedure-related mortality is high (16%) for BAS with refractory hypoxemia being the most common cause of death. The procedure may also need to be repeated due to spontaneous closure of the atrial septal defect. \r\n\r\n\r\nInitiation of epoprostenol, a prostacyclin analogue, will unlikely provide additional benefit since the patient is already on treprostinil, which is in the same category of medications. Initiation of inhaled nitric oxide will likely not provide additional benefit in a patient with pulmonary veno-occlusive disease, which is a fixed obstruction. Placement of a Potts shunt is the most appropriate treatment in a patient with medically refractory, suprasystemic pulmonary arterial hypertension in order to decrease the RV afterload. \r\n\r\n\r\nReferences \r\n\r\n1.\t van Loon RL, Roofthooft MT, Hillege HL, et al. Pediatric pulmonary hypertension in the Netherlands: epidemiology and characterization during the period 1991 to 2005. Circulation<\/em>. 2011; 124(16): 1755-1764. \r\n\r\n\r\n2.\t Montani D, Lau EM, Dorfm\u00fcller P, et al. Pulmonary veno-occlusive disease. Eur Respir J<\/em>. 2016; 47(5): 1518-1534. doi:10.1183\/13993003.00026-2016 \r\n\r\n\r\n\r\n3.\t Tuder RM, Cool CD, Geraci MW, et al. Prostacyclin synthase expression is decreased in lungs from patients with severe pulmonary hypertension.\u202f Am J Respir Crit Care Med<\/em>.\u202f1999; 159(6): 1925-1932. \r\n\r\n\r\n4.\t Cacoub P, Dorent R, Nataf P, Carayon A. Endothelin-1 in pulmonary hypertension. N Engl J Med<\/em>.\u202f1993; 329(26): 1967-1968. \r\n\r\n\r\n5.\t Maguire JJ, Davenport AP. Endothelin receptors and their antagonists. Semin Nephrol<\/em>. 2015; 35(2): 125-136. \r\n\r\n\r\n6.\t Aggarwal M, Grady RM, Choudhry S, Anwar S, Eghtesady P, Singh GK. Potts Shunt Improves Right Ventricular Function and Coupling With Pulmonary Circulation in Children With Suprasystemic Pulmonary Arterial Hypertension. Circ Cardiovasc Imaging<\/em>. 2018; 11(12): e007964. doi:10.1161\/CIRCIMAGING.118.007964 \r\n\r\n\r\n7.\t Garekar S, Meeran T, Dhake S, Malankar D. Valved reverse Potts shunt in a case of pulmonary hypertension due to pulmonary veno-occlusive disease. Indian J Thorac Cardiovasc Surg<\/em>. 2021; 37(1): 89-92. doi:10.1007\/s12055-020-00993-2 \r\n\r\n\r\n8.\tGrady RM. Beyond transplant: Roles of atrial septostomy and Potts shunt in pediatric pulmonary hypertension. Pediatr Pulmonol<\/em>. 2021; 56(3): 656-660. doi:10.1002\/ppul.25049 \r\n\r\n\r\n9.\tKeogh AM, Mayer E, Benza RL, et al. Interventional and surgical modalities of treatment in pulmonary hypertension. J Am Coll Cardiol<\/em>. 2009; 54(1 Suppl): S67-S77. doi:10.1016\/j.jacc.2009.04.016 \r\n\r\n\r\n10.\tKim SH, Jang WS, Lim HG, Kim YJ. Potts shunt in patients with primary pulmonary hypertension. Korean J Thorac Cardiovasc Surg<\/em>. 2015; 48(1): 52-54. doi:10.5090\/kjtcs.2015.48.1.52 \r\n\r\n\r\n11.\tRosenzweig EB, Ankola A, Krishnan U, Middlesworth W, Bacha E, Bacchetta M. A novel unidirectional-valved shunt approach for end-stage pulmonary arterial hypertension: Early experience in adolescents and adults. J Thorac Cardiovasc Surg<\/em>. 2021; 161(4): 1438-1446.e2. doi: 10.1016\/j.jtcvs.2019.10.149. Epub 2019 Nov 14. PMID: 31839227. \r\n”,”redirect_url”:””}}}}}

{“questions”:{“7q7ak”:{“id”:”7q7ak”,”mediaType”:”image”,”answerType”:”text”,”imageCredit”:””,”image”:””,”imageId”:””,”video”:””,”imagePlaceholder”:””,”imagePlaceholderId”:””,”title”:”Author: Sana Ullah, MB, ChB, FRCA \u2013 Children\u2019s Medical Center, Dallas\r\n\r\nWhat is the MOST COMMON indication for surgical or catheter-based interventions following an arterial switch operation?\r\n\r\n”,”desc”:””,”hint”:””,”answers”:{“jbj6u”:{“id”:”jbj6u”,”image”:””,”imageId”:””,”title”:”A.\tCoronary stenosis”},”9kdwv”:{“id”:”9kdwv”,”image”:””,”imageId”:””,”title”:”B.\tNeoaortic root dilatation”},”1x38l”:{“id”:”1x38l”,”image”:””,”imageId”:””,”title”:”C.\tNeoaortic valve dilatation”},”ih5e9″:{“id”:”ih5e9″,”image”:””,”imageId”:””,”title”:”D.\tRight ventricular outflow tract obstruction”,”isCorrect”:”1″}}}},”results”:{“q2zi8”:{“id”:”q2zi8″,”title”:””,”image”:””,”imageId”:””,”min”:”0″,”max”:”1″,”desc”:”The arterial switch operation (ASO) was introduced in 1975 and is now the standard surgical procedure for simple and complex forms of Transposition of the Great Arteries (TGA). Long-term survival is over 95% at 10 and 25 years with an excellent quality of life. Two recent single-center studies investigating the long term complications up to 40 years after an ASO have confirmed previously published findings and reveal new insights, emphasizing the need for life-long follow-up. \r\n\r\n\r\nThe most common indication for surgical or catheter-based interventions after an ASO is right ventricular outflow tract obstruction (RVOTO). RVOTO is found most frequently at the level of the branch pulmonary arteries (PAs) but also at the pulmonary valve and main pulmonary artery. Balloon dilation is effective but has a high recurrence rate of re-stenosis which then necessitates stent placement. The onset of pulmonary stenosis can be as early as 30 days or as late as 10 years after the initial operation. There are several reasons hypothesized as the cause of RVOTO. One potential cause is the LeCompte maneuver which when performed by the surgeon relocates the pulmonary trunk and branches over the aortic root. If the aortic root or ascending aorta becomes dilated, there may be resultant PA compression. Other potential contributing factors to RVOTO include extent of mobilization of the PAs, inadequate dissection of the branch PAs, age at the time of operation, and size mismatch of the switched great vessels.. In one recent study, surgical correction of RVOTO was required in 50% of patients and catheter-based interventions in 76% of patients who had previously undergone an ASO. \r\n\r\n\r\nThe second most common indication for reoperation or reintervention is neoaortic valve regurgitation with neoaortic root dilatation. Approximately 15%-18% of patients require surgical intervention with neoaortic valve replacement or repair and\/or ascending aorta replacement, such as a Bentall procedure. \r\n\r\n\r\nCoronary stenosis and coronary ischemia necessitating revascularization are the most common causes of early mortality, but occur rarely, in approximately 2-6% of patients, as long-term complications after an ASO. \r\n \r\n\r\nReferences\r\n\r\n\r\n(1)\tVan der Palen RLF, Blom NA, Kuipers IM, et al. Long-term outcome after the arterial switch operation: 43 years of experience. Eur J Cardiothorac Surg<\/em>. 2021; 59(5): 968-977. \r\n\r\n\r\n(2)\tFricke TA, Buratto E, Weintraub RG, et al. Long-term outcomes of the arterial switch operation. [Published online ahead of print February 11 2021]. J Thorac Cardiovas Surg<\/em>. 2021. doi:10.1016\/j.jtcvs.2021.01.134. \r\n”,”redirect_url”:””}}}

{“questions”:{“sjmix”:{“id”:”sjmix”,”mediaType”:”image”,”answerType”:”text”,”imageCredit”:””,”image”:””,”imageId”:””,”video”:””,”imagePlaceholder”:””,”imagePlaceholderId”:””,”title”:”Author: Sana Ullah, MB ChB, FRCA – Children\u2019s Medical Center, Dallas\r\n\r\n\r\nA 14-year-old boy with a history of Wolff-Parkinson-White (WPW) Syndrome is admitted to the hospital with acute appendicitis. He is brought to the operating room for an appendectomy and 30 seconds after intubation he develops atrial fibrillation. The blood pressure and heart rate are stable. Which of the following interventions is the MOST APPROPRIATE to treat the arrhythmia?\r\n”,”desc”:””,”hint”:””,”answers”:{“vz2ov”:{“id”:”vz2ov”,”image”:””,”imageId”:””,”title”:”A.\tAdenosine”},”t9kj1″:{“id”:”t9kj1″,”image”:””,”imageId”:””,”title”:”B.\tEsmolol”},”2690y”:{“id”:”2690y”,”image”:””,”imageId”:””,”title”:”C.\tDC cardioversion”},”vm4oq”:{“id”:”vm4oq”,”image”:””,”imageId”:””,”title”:”D.\tProcainamide”,”isCorrect”:”1″}}}},”results”:{“a6tpd”:{“id”:”a6tpd”,”title”:””,”image”:””,”imageId”:””,”min”:”0″,”max”:”1″,”desc”:”Wolff-Parkinson-White (WPW) syndrome is a form of pre-excitation with characteristic abnormalities on the ECG and an increased predisposition to tachyarrhythmias involving an accessory pathway. It results from the presence of one or more accessory pathways (AP) of conduction between the atria and the ventricles. The AP conducts electrical impulses faster resulting in a shorter PR interval in the surface ECG and has a shorter refractory period than the atrioventricular node (AVN). The typical findings of AP function in sinus rhythm are preexcitation, in which depolarization of the ventricles occurs in part or fully through the accessory pathway that is separate from the AVN and earlier than expected after atrial depolarization. This results in shortening of the PR interval and a delta wave followed by a prolonged or widened QRS complex. The short refractory period leads to more rapid transmission of atrial impulses, which can result in supraventricular tachycardia. The typical supraventricular tachycardia associated with WPW syndrome is atrioventricular reentrant or reciprocating tachycardia (AVRT). AVRT is further classified into orthodromic AVRT and antidromic AVRT. Pre-excited atrial fibrillation or atrial flutter with rapid ventricular response may also occur. \r\n\r\n\r\nThe perioperative period is a particularly high-risk time period in which arrhythmias are more likely to occur due to an imbalance in parasympathetic and sympathetic tone. For example, the administration of neostigmine which causes slowing of the heart rate due to decreased atrioventricular nodal conduction can divert conduction to the accessory pathway. Similarly, sympathetic stimulation due to pain, laryngoscopy or emergence from anesthesia can cause tachycardia with a resultant increased number of impulses being transmitted via the AP. \r\n\r\n\r\nAcute treatment of arrhythmias in the setting of WPW can be challenging. Patients are typically treated for symptomatic arrhythmias or if certain high-risk features are present in asymptomatic patients. Hemodynamically significant arrhythmias require immediate direct current (DC) cardioversion. Catheter ablation is almost always preferred for long-term prevention of recurrent arrhythmias involving an accessory pathway. In situations of stable hemodynamics and acute onset, pharmacological treatment is usually effective. If time allows or if there is any doubt about the diagnosis, expert cardiology consultation is warranted. The presence of an accessory pathway influences the choice of correct pharmacologic treatment. \r\n\r\n\r\nA stable narrow complex tachycardia typically results from orthodromic AVRT with antegrade conduction via the AVN followed by retrograde conduction along the AP. Orthodromic AVRT occurs in 90 to 95 percent of reentrant tachycardias linked with WPW syndrome. AV nodal blocking drugs are the first-line therapy. Adenosine is usually effective. Verapamil is also effective, but caution is advised in the setting of hypotension or diminished ventricular function. A short-acting beta-blocker such as esmolol is another option. \r\n\r\n\r\nA stable wide-complex tachycardia results from antidromic AVRT with antegrade conduction over the accessory pathway and onto the ventricles followed by retrograde conduction back to the atria via the AVN. Wide complex tachycardia may also result from orthodromic AVRT with aberrant QRS conduction resulting in a wide QRS complex. Stable wide complex tachycardia may also be ventricular tachycardia. In the case of antidromic AVRT, the best option is procainamide, which is classified as a sodium-channel blocker that slows conduction in both the AVN and the AP. If the exact mechanism of wide complex is not certain, the presumptive diagnosis should be ventricular tachycardia and treated accordingly. \r\n\r\n\r\nAtrial fibrillation (AF) can be very dangerous in the setting of WPW, as conduction of atrial impulses at rates of up to 500 beats per minute can result in ventricular tachycardia or ventricular fibrillation. In this setting, AV nodal blocking drugs such as adenosine, verapamil, digoxin and esmolol are contraindicated as their use will divert atrial impulses to the AP. The recommended first-line treatment is procainamide to restore sinus rhythm. For young children, the dose recommended is 10-15 milligrams per kilogram over 15 to 30 minutes followed by an infusion of 20 to 80 micrograms per kg per minute. If ineffective, an intravenous loading dose of amiodarone followed by an infusion can be attempted. However, amiodarone use should be carried out with caution as its av-nodal blocking properties may increase conduction via an accessory pathway. Practitioners should be prepared to treat degradation of atrial fibrillation to ventricular fibrillation with immediate defibrillation. Pharmacologic cardioversion of atrial fibrillation may be slow. While under anesthesia, DC cardioversion is still an appropriate option for treatment, even in the setting of a stable rhythm if resolution with pharmacologic agents does not occur within a short period of time. \r\n\r\n\r\nReferences\r\n\r\n\r\n(1)\tDi Biase, L, Walsh EP. Treatment of symptomatic arrhythmias associated with Wolff-Parkinson-White Syndrome. In UpToDate, Levy S, Knight BP (Eds), UpToDate<\/em>, Waltham, MA. (Accessed on June 17, 2021.) \r\n\r\n\r\n(2)\tDi Biase, L, Walsh EP. Wolff-Parkinson syndrome: Anatomy, epidemiology, clinical manifestations, and diagnosis. In UpToDate<\/em>, Levy S, Knight BP (Eds), UpToDate, Waltham, MA. (Accessed on June 17, 2021.) \r\n\r\n\r\n(3)\tDi Biase, L, Walsh EP.Wolff-Parkinson syndrome: Atrioventricular reentrant tachycardia (AVRT) associated with an accessory pathway. In UpToDate<\/em>, Levy S, Knight BP (Eds), UpToDate, Waltham, MA. (Accessed on June 17, 2021.) \r\n\r\n\r\n(4)\tJanuary CT, Wann LS, Alpert JS et al. ACC\/AHA Task Force Members. 2014 AHA\/ACC\/HRS Guideline for the management of patients with atrial fibrillation: executive summary: a report of the American College of Cardiology\/American Heart Association Task Force on practice guidelines and the Heart Rhythm Society. Circulation. 2014; 130(23): 2071-2104. \r\n\r\n\r\n(5)\tBengali R, Wellens HJJ, Jiang Y. Perioperative Management of the Wolff-Parkinson-White Syndrome. J Cardiothorac Vasc Anesth<\/em>. 2014; 28(5): 1375-1386. doi: 10.1053\/j.jvca.2014.02.003. Epub 2014 Jul 11. \r\n\r\n\r\n\r\n\r\n”,”redirect_url”:””}}}