{“questions”:{“970sp”:{“id”:”970sp”,”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 six-year-old child with a secundum atrial septal defect (ASD) presents for a transcatheter ASD device closure. Transthoracic echocardiographic imaging reveals a large ASD with moderate right atrial and ventricular enlargement. What is the MOST LIKELY reason that a Gore Septal Occluder may be preferred versus the Amplatzer Septal Occluder for closure of this defect?\r\n”,”desc”:””,”hint”:””,”answers”:{“zp6ht”:{“id”:”zp6ht”,”image”:””,”imageId”:””,”title”:”A. The Gore Septal Occluder requires a minimal rim for deployment”},”t2say”:{“id”:”t2say”,”image”:””,”imageId”:””,”title”:”B. The Gore Septal Occluder can be placed without echocardiographic guidance”},”u2yaa”:{“id”:”u2yaa”,”image”:””,”imageId”:””,”title”:”C. The Gore Septal Occluder has a low likelihood of device erosion”,”isCorrect”:”1″},”wo88n”:{“id”:”wo88n”,”image”:””,”imageId”:””,”title”:”D. The Gore Septal Occluder does not require aspirin treatment”}}}},”results”:{“l477h”:{“id”:”l477h”,”title”:””,”image”:””,”imageId”:””,”min”:”0″,”max”:”1″,”desc”:”Atrial septal defects (ASD) are one of the most common congenital cardiac defects in the pediatric population. ASD closure is indicated when the resultant left to right shunt leads to right ventricular volume overload and\/or a ratio of total pulmonary blood flow to systemic blood flow (Qp<\/sub>:Qs<\/sub>) greater than or equal to 1.5: 1. Additional indications for ASD closure include cyanosis and\/or embolic episodes secondary to right to left shunting. Possible contraindications to ASD closure include evidence of pulmonary hypertension with an elevated pulmonary vascular resistance and reduced right ventricular compliance or function.
\r\n\r\nASDs can be closed either surgically or percutaneously via transcatheter intervention. The decision regarding which method of closure to pursue is based on several factors including anatomic criteria, device specific limitations, and possible complications. Transcatheter techniques and device properties have become more refined and as a result, ASD device closure is now accepted as the preferred treatment of choice. Transcatheter closure has excellent clinical efficacy as well as a lower complication rate compared to surgical closure. However, surgical closure is still preferred in patients who have a low body weight, a defect greater than 38mm in diameter, deficient rims, and\/or multiple\/complex defects.
\r\n\r\n\r\nTranscatheter device closure of an ASD in the cardiac catheterization lab usually involves the following steps:
\r\n\r\n1.\tA hemodynamic cardiac catheterization and assessment of the morphologic characteristics of the defect.
\r\n\r\n2.\tEstablishment of a procedural strategy for device implantation including an imaging modality (i.e.TEE, ICE, TTE, etc.).
\r\n\r\n3.\t Selection of the optimal device type and size.
\r\n\r\n4.\t Device implantation with appropriate surveillance of potential complications.
\r\n\r\n5.\t Post implantation assessment.
\r\n\r\n\r\nLarge defects represent the main source of challenge for the transcatheter ASD device closure procedure. In this circumstance, problems arise secondary to difficulty in correctly sizing the defect or from the prolapse of left atrial disk of the closure device into the right atrium before proper positioning in the septum. Large defects are frequently associated with rim deficiency. Patients with deficient rims are at risk for device dislodgment, embolization, erosion, and\/or encroachment into nearby cardiac structures as an ASD is surrounded by vital cardiac structures throughout its circumference.
\r\n\r\n\r\nBalloon sizing is performed in order to select the correct device. It also provides information about the compliance of the rims. The balloon stretched diameter or balloon occlusive diameter is used to approximate the defect size, but the stop flow diameter (SFD) measurement is standardly recommended to avoid oversizing. In devices such as the Amplatzer Septal Occluder (ASO) (St. Jude Medical, St. Paul, MN, USA), the recommended device size is usually the same or slightly larger (<2 mm) than the SFD. Ultimately, the selection for device size should be individualized by assessing for rim deficiency and evaluating the spatial relationship of nearby structures.
\r\n\r\n\r\nThere are many commercially available devices for percutaneous ASD closure. The first device developed was the Amplatzer Septal Occluder (ASO). More recent devices include the Gore Cardioform Septal Occluder (GSO) (WL Gore & Associates, Inc., Flagstaff, AZ, USA), the Figulla Flexible Occlutech device, the Cardioseal\/Starflex, and the bioabsorbable devices (Biostar or Biotrek). The ASO is a self-centering device with the ability to close defects from 4 to 38mm due to its diameter size while the GSO is a non-self-centering device with the ability to close defects from 15 to 18mm.
\r\n\r\n\r\nThe ASO was the first self-expanding double-disk device. The device allows for straightforward deployment as it is self-centering, repositionable, and recapturable. With a self-centering device, the waist sits inside the ASD and completely occupies the defect. The edges of the device remain at a fixed distance from the atrial free wall regardless of the timing of the cardiac cycle. Therefore, an oversized device may tent the atrial free wall throughout the cardiac cycle making it vulnerable to trauma. The self-centering characteristic of the ASO necessitates device selection to closely approximate the defect diameter. A stop-flow diameter sizing technique is recommended for the ASO.
\r\n\r\n\r\nAn initial study demonstrated a high success rate of ASD closure (95.7%) with few reported major adverse events (1.6%) with the ASO. The subsequent MAGIC study and IMPACT registry reported compatible success and complication rates. The risk of device erosion has become increasingly concerning as it may be fatal and may be delayed. The exact rate of device erosion is estimated to be 0.1 to 0.3%.
\r\n\r\n\r\nThe GSO is a non-self-centering double disk device composed of a platinum filled nitinol wire framework covered with an expanded polytetrafluoroethylene membrane to promote rapid endothelialization. When the GSO is fully deployed it assumes a double-disc configuration that bridges the septal defect to prevent shunting of blood between the right and left atria. To effectively close the ASD, the discs must be approximately twice the diameter of the ASD. The GSO is preferred for closure of small defects, particularly those with aortic rim deficiency, due to its flexibility with minimal metal content which may prevent erosion. Clinical studies have verified the efficacy and safety of GSO in closing ASDs with various morphologies. The GSO can adjust to contraction of the atrial chamber because it is a non-self-centering device.
\r\n\r\n\r\nAll of the ASD percutaneous closure devices have excellent efficacy and safety profiles. Serious adverse effects occur in less than 1% of patients and more than 95% of the defects can be closed safely. Major catheterization complications specific to this procedure may appear even after completion of the procedure, such as stroke and AV block. The activated clotting time should be at least 250 seconds throughout the procedure, and heparin should never be reversed at the conclusion of the procedure because it increases the risk of thrombus formation on the device. The most common complication reported to the manufacturers and the FDA is device embolization. Device embolization most commonly occurs in the cardiac catheterization laboratory or during the first 24 hours after device placement. The opposite is true of device-related erosion, which is rarely appreciated in the cardiac catheterization laboratory. However, the risk increases significantly during the first 96 hours with sporadic cases reported after 6 months to several years after implantation. To date, device erosion has been noted with the ASO. It is typically, although not exclusively, seen in cases where either the ASO was oversized or there was deficient anterosuperior or retro-aortic rim. Erosion occurring in cases without device oversizing remains of significant concern. To further minimize the risk of erosion, correct device sizing by carefully and non-aggressively employing the stop-flow balloon diameter method is recommended. Patients with aortic rim deficiency spanning 30\u00ba or more should not be selected for device closure.
\r\n\r\n\r\nTo date, there are no known cases of erosion with the GSO, however, long term follow-up data is unavailable due to it recently being commercially approved. There is a new GSO now available that is a hybrid of the ASO and original GSO allowing for decreased incidence of device erosion and the ability to close ASDs measuring greater than or equal to 18mm as demonstrated in the ASSURED clinal study.
\r\n\r\n\r\nThe correct answer is that the GSO has a low likelihood of device erosion compared to the ASO. The GSO device has not demonstrated any cases of device erosion to date. GSO does not require minimal rim for deployment and rim deficiency may be a contraindication to placement. ASO and GSO are both placed with guidance by echocardiography. ASO and GSO require anticoagulation due to risk of device thrombosis. The devices have metal and\/or polyester mesh components so most patients are started prophylactically on aspirin and\/or clopidogrel. Dual antiplatelet therapy is typically continued post-procedurally for 3 months and aspirin for up to 6 months (device endothelialization).
\r\n\r\n\r\n\r\nReferences
\r\n1.\tde Hemptinne Q, Horlick EM, Osten MD, et al. Initial clinical experience with the GORE\u00aeCARDIOFORM ASD occluder for transcatheter atrial septal defect closure. Catheter Cardiovasc Interv<\/em>. 2017; 90(3): 495-503. doi:10.1002\/ccd.26907 ——————–\r\n\r\n2.\tFaccini A, Butera G. Atrial septal defect (ASD) device trans-catheter closure: limitations. J Thorac Dis<\/em>. 2018; 10(Suppl 24): S2923-S2930. doi:10.21037\/jtd.2018.07.128 ——————–\r\n\r\n3.\tDu ZD, Hijazi ZM, Kleinman CS, et al. Comparison between transcatheter and surgical closure of secundum atrial septal defect in children and adults: results of a multicenter nonrandomized trial. J Am Coll Cardiol<\/em>. 2002; 39: 1836-1844.——————–\r\n\r\n4.\tFraisse A, Latchman M, Sharma SR, et al. Atrial septal defect closure: indications and contraindications. J Thorac Dis<\/em>. 2018; 10(Suppl 24): S2874-S2881. doi:10.21037\/jtd.2018.08.111 ———————\r\n\r\n5.\tOlasinska-Wisniewska A, Grygier M. Antithrombotic\/Antiplatelet Treatment in Transcatheter Structural Cardiac Interventions-PFO\/ASD\/LAA Occluder and Interatrial Shunt Devices. Front Cardiovasc Med<\/em>. 2019; 6: 75. Published 2019 Jun 7. doi:10.3389\/fcvm.2019.00075 ——————–\r\n\r\n6.\tS\u00f8ndergaard L, Loh PH, Franzen O, et al. The first clinical experience with the new GORE\u00ae septal occluder (GSO). EuroIntervention<\/em> 2013; 9: 959-963. ——————–\r\n\r\n\r\n7.\tSmith B, Thomson J, Crossland D, et al. UK multicenter experience using the Gore septal occluder (GSO(TM)) for atrial septal defect closure in children and adults. Catheter Cardiovasc Interv<\/em> 2014; 83: 581-586. ——————–\r\n\r\n8.\tSantoro G, Castaldi B, Cuman M, et al. Trans-catheter atrial septal defect closure with the new GORE\u00ae Cardioform ASD occluder: First European experience. Int J Cardiol<\/em>. 2021; 327: 68-73. doi:10.1016\/j.ijcard.2020.11.029 ——————–\r\n\r\n9.\tSommer RJ, Love BA, Paolillo JA, et al. ASSURED clinical study: New GORE\u00ae CARDIOFORM ASD occluder for transcatheter closure of atrial septal defect. Catheter Cardiovasc Interv<\/em>. 2020; 95(7): 1285-1295. doi:10.1002\/ccd.28728 ——————–\r\n\r\n10.\tYang MC, Wu JR. Recent review of transcatheter closure of atrial septal defect. Kaohsiung J Med Sci<\/em>. 2018; 34(7): 363-369. doi:10.1016\/j.kjms.2018.05.001 ———————\r\n\r\n11.\tAmin Z, Hijazi ZM, Bass JL, et al. Erosion of Amplatzer septal occluder device after closure of secundum atrial septal defects: review of registry of complications and recommendations to minimize future risk. Catheter Cardiovasc Interv<\/em>. 2004; 63: 496-502. ——————–\r\n\r\n12.\tKrumsdorf U, Ostermayer S, Billinger K, et al. Incidence and clinical course of thrombus formation on atrial septal defect and patent foramen ovale closure devices in 1,000 consecutive patients. J Am Coll Cardiol<\/em>. 2004; 43: 302-309. ——————–\r\n\r\n13.\tLevi DS, Moore JW. Embolization and retrieval of the Amplatzer septal occluder. Catheter Cardiovasc Interv<\/em>. 2004; 61: 543-547. ———————\r\n\r\n14.\tEverett AD, Jennings J, Sibinga E, et al. Community use of the amplatzer atrial septal defect occluder: results of the multicenter MAGIC atrial septal defect study. Pediatr Cardiol<\/em> 2009; 30: 240-247. ———————\r\n\r\n15.\tMoore JW, Vincent RN, Beekman RH 3rd, et al. Procedural results and safety of common interventional procedures in congenital heart disease: initial report from the National Cardiovascular Data Registry. J Am Coll Cardiol<\/em> . 2014; 64: 2439-2451. ———————-\r\n\r\n16.\tDiab K, Kenny D, Hijazi ZM. Erosions, erosions, and erosions! Device closure of atrial septal defects: how safe is safe? Catheter Cardiovasc Interv<\/em>. 2012; 80: 168-174. ——————–\r\n\t\r\n17.\tCrawford GB, Brindis RG, Krucoff MW, et al. Percutaneous atrial septal occluder devices and cardiac erosion: a review of the literature. Catheter Cardiovasc Interv<\/em> . 2012; 80: 157-167. ——————–\r\n\r\n18.\tMcElhinney DB, Quartermain MD, Kenny D, et al. Relative Risk Factors for Cardiac Erosion Following Transcatheter Closure of Atrial Septal Defects: A Case-Control Study. Circulation<\/em>. 2016; 133: 1738-1746. “,”redirect_url”:””}}}
Question of the Week 327
{“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”:””}}}
Question of the Week 326
{“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”:””}}}
Question of the Week 325
{“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 ETA<\/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\/m2<\/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.
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Question of the Week 324
{“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”:””}}}