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

{“questions”:{“02yzs”:{“id”:”02yzs”,”mediaType”:”image”,”answerType”:”text”,”imageCredit”:””,”image”:””,”imageId”:””,”video”:””,”imagePlaceholder”:””,”imagePlaceholderId”:””,”title”:”Author: Anna Hartzog MD and Chinwe Unegbu MD \u2013 Children\u2019s National Hospital \r\n\r\nA 2-month-old infant with dilated cardiomyopathy presents for Left Ventricular Assist Device (LVAD) insertion. The surgeon implants a Levitronix CentriMag pump with Berlin Heart Excor cannulas. What is the MOST LIKELY benefit of initial placement of the CentriMag pump over initial insertion of the complete Berlin Excor system? \r\n\r\n”,”desc”:””,”hint”:””,”answers”:{“7nnsc”:{“id”:”7nnsc”,”image”:””,”imageId”:””,”title”:”A. Anticipated need for long-term VAD support”},”ljm8f”:{“id”:”ljm8f”,”image”:””,”imageId”:””,”title”:”B. No anticoagulation needed with the CentriMag pump “},”gxo1n”:{“id”:”gxo1n”,”image”:””,”imageId”:””,”title”:”C. Reduced hospital costs in the immediate perioperative period”,”isCorrect”:”1″},”g9xok”:{“id”:”g9xok”,”image”:””,”imageId”:””,”title”:”D. Improved chances of myocardial recovery “}}}},”results”:{“j3qmg”:{“id”:”j3qmg”,”title”:””,”image”:””,”imageId”:””,”min”:”0″,”max”:”1″,”desc”:”Approximately 20% to 30% of pediatric patients awaiting heart transplantation are bridged with a Ventricular Assist Device (VAD). This has resulted in a 50% reduction in the waitlist mortality. Candidacy for VAD implantation is often determined by serial monitoring for end-organ dysfunction (ie hepatic, renal, gastrointestinal dysfunction), nutritional status, level of inotropic support, and degree of respiratory compromise. Generally, VAD therapy should occur prior to the onset of severe end-organ dysfunction as this is an independent risk factor of mortality.\r\n\r\n\r\nSmall children and infants have limited device options. The majority of children who require a VAD are supported with either a pulsatile paracorporeal device or a continuous flow intracorporeal device. The Berlin Heart Excor VAD (Berlin Heart GmbH, Berlin, Germany) is a pulsatile paracorporeal device that is situated externally. The main continuous flow intracorporeal devices are the HeartWare HVAD (Medtronic, Minneapolis, MN) and the HeartMate 3 (Abbott Corporation, Abbott Park, IL) which have pumps that are implanted internally. The HeartWare HVAD and HeartMate 3 are currently US Food and Drug Administration-approved for the therapy of advanced heart failure in adults. However, both devices have been safely and successfully used in patients as small as twenty kilograms and body surface area of 0.6 m^{2<\/sup>. Continuous flow VADs have a 92% survival rate at 6 months, which is superior to the survival rates in pediatric patients with pulsatile devices.\r\n\r\n\r\nThe Berlin Heart Excor VAD is a pneumatically-driven, pulsatile pump with a fixed volume chamber ranging from 10 to 80 milliliters. During systole the pump moves compressed air into the pneumatic chamber causing ejection. In diastole negative pressure is applied to the pneumatic chamber to aid filling. Cardiac output is dependent on the size of the chamber and the pump rate. Unfortunately, complications such as stroke, bleeding, and infection are more common with the Berlin Heart EXCOR in comparison to continuous flow devices. \r\n\r\n\r\nIn addition to durable long-term VADs, temporary or short-term VADs also exist. Temporary circulatory support devices are traditionally defined as those providing support for two to four weeks as a \u201cbridge to recovery\u201d or \u201cbridge to decision\u201d in patients with an acute process. Temporary circulatory support devices now account for 19% of VAD implants. In 2018 Lorts et al used data from the Pediatric Interagency Registry for Mechanical Circulatory Support (PediMACS) to investigate outcomes in patients temporarily supported by VADs. The authors found that 71% had a positive outcome (ie bridge to recovery, bridge to transplant, bridge to a durable device, or alive with a device). Additionally, the authors also discovered that \u201ctemporary\u201d devices were utilized for a wide variety of indications and for durations of time greater than six weeks.\r\n\r\n\r\nThe CentriMag\/PediMag (Levitronix LLC, Waltham, MA) is a third generation paracorporeal continuous flow device that is being used with increasing frequency for temporary circulatory support. The CentriMag is driven with a bearingless motor, enabling the spinning component within the pump to be magnetically levitated and rotated without contact or wear. By eliminating the bearings, shafts, and seals associated with a conventional centrifugal pump, the incidence of thrombus accumulation and the degree of hemolysis are greatly reduced, which decreases the risk of adverse events. As there is low risk of thromboembolic events, many centers use minimal anticoagulation. This is advantageous after VAD implantation as a significant percentage of patients require re-exploration due to bleeding. In contrast, the Berlin Heart Excor system requires early initiation of anticoagulation therapy. \r\n\r\n\r\nThe need for minimal anticoagulation and lower hospital-related costs have made the CentriMag pump in combination with the Berlin Heart Excor cannulas a logical choice in some centers. This combination allows the CentriMag pump to stabilize the patient over a period of several weeks. Then once stabilized, the Berlin Heart Excor pump and drive unit can replace the CentriMag. The pump exchange can be accomplished in one to two minutes. The CentriMag pump is less expensive with a cost of $10,000 to $13,000 per pump. In comparison, the Berlin Heart Excor pump costs $39,000 and the driver monthly rental is approximately $10,000. Immediately following VAD implantation, there is considerable inflammation leading to fibrin and clot build up that may necessitate several pump exchanges. Pump exchange is quite expensive, especially with use of the Berlin Excor system. The combined use of both systems can be viewed as a cost effective \u201cbridge to a bridge\u201d.\r\n\r\n\r\nChoice C is the correct answer as perioperative costs are reduced with the CentriMag. Choice A, B and D are incorrect as the Centrimag is not intended for long-term support, requires some form of anticoagulation, and is not associated with improved myocardial recovery.\r\n\r\n\r\nReferences\r\n\r\n1.\tNavaratnam M, Maeda K, Hollander SA. Pediatric ventricular assist devices: Bridge to a new era of perioperative care. Pediatric Anesthesia<\/em>. 2019; 29: 506\u2013518. doi:10.1111\/pan.13609.\r\n\r\n\r\n2.\tVanderPluym CJ, Adachi I, Niebler R, et al. Outcomes of children supported with an intracorporeal continuous-flow left ventricular assist system. J Heart Lung Transplant<\/em>. 2019; 38(4): 385-393.\r\n\r\n3.\tChatterjee A, Feldmann C, Hanke JS, et al. The momentum of HeartMate 3: a novel active magnetically levitated centrifugal left ventricular assist device (LVAD). J Thorac Dis<\/em>. 2018; 10(Suppl 15): S1790-S1793. \r\n\r\n4.\tO\u2019Connor MJ, Lorts A, Davies RR, et al. Early experience with the HeartMate 3 continuous flow ventricular assist device in pediatric patients and patients with congenital heart disease: A multicenter registry analysis. J Heart Lung Transplant<\/em>. 2020; 39: 573-579.\r\n\r\n5.\tAlmond CS, Morales DL, Blackstone EH, et al. Berlin heart EXCOR pediatric ventricular assist device for bridge to heart transplantation in US children. Circulation<\/em>. 2013; 127: 1702\u20101711. doi: 10.1161\/CIRCULATIONAHA.112.000685. \r\n\r\n6.\tBlume ED, VanderPluym C, Lorts A, et al. Second annual Pediatric Interagency Registry for Mechanical Circulatory Support (Pedimacs) report: Pre\u2010implant characteristics and outcomes. J Heart Lung Transplant<\/em>. 2018; 37(1): 38\u201045. doi: 10.1016\/j.healun.2017.06.017.\r\n\r\n\r\n7.\tLorts A, Eghtesady P, Mehegan M, et al. Outcomes of children supported with devices labeled as \u201ctemporary\u201d or short term: A report from the Pediatric Interagency Registry For Mechanical Circulatory Support. J Heart Lung Transplant<\/em>. 2018; 37(1): 54\u201060. doi:10.1016\/j.healun.2017.10.023. \r\n\r\n8.\tStiller B, Lemmer J, Schubert S, et al. Management of pediatric patients after implantation of the Berlin Heart EXCOR ventricular assist device. ASAIO J<\/em>. 2006; 52(5): 497-500. PMID: 16966844.\r\n\r\n\r\n9.\tDe Rita F, Hasan A, Haynes S, et al. Outcome of mechanical cardiac support in children using more than one modality as a bridge to heart transplantation. Eur J Cardiothorac Surg<\/em>. 2015; 48: 917-922. doi:10.1093\/ejcts\/ezu544.\r\n\r\n10.\tConway J, Al-Aklabi M, Granoski D, et al. Supporting pediatric patients with short-term continuous-flow devices. J Heart Lung Transplant<\/em>. 2016; 35: 603-609. doi:10.1016\/j.healun.2016.01.1224. \r\n\r\n11.\tMaat A.P, van Thiel R.J, Dalinqhaus M, Bogers A.J. Connecting the CentriMag Levitronix pump to Berlin Heart Excor cannula. J Heart Lung Transplant<\/em>. 2008; 27: 112-115. doi: 10.1016\/j.healun.2007.10.010 \r\n\r\n\r\n12.\t Loforte A, Potapov E, Krabatsch T, et al. Levitronix CentriMag to Berlin Heart Excor: A \u201cBridge to Bridge\u201d Solution in Refractory Cardiogenic Shock. ASAIO J<\/em>. 2009; 55(5): 465-468. doi: 10.1097\/MAT.0b013e3181b58c50 \r\n\r\n13.\tJohn R, Long J, Massey T, et al. Outcomes of a multicenter trial of the Levitronix CentriMag ventricular assist system for short-term circulatory support. Mechanical Circulatory Support<\/em>. 2008; 27(1): 112-115. doi:https:\/\/doi.org\/10.1016\/j.jtcvs.2010.03.046 \r\n\r\n\r\n”,”redirect_url”:””}}}}

{“questions”:{“yv9hs”:{“id”:”yv9hs”,”mediaType”:”image”,”answerType”:”text”,”imageCredit”:””,”image”:””,”imageId”:””,”video”:””,”imagePlaceholder”:””,”imagePlaceholderId”:””,”title”:”Authors: Anna Hartzog MD and Chinwe Unegbu MD \u2013 Children\u2019s National Hospital \r\n\r\nA 1-day old neonate with critical aortic stenosis and decreased left ventricular function is intubated due to respiratory failure, pulmonary edema and increasing left atrial pressures. The patient presents to the operating room for surgical repair. What is the GREATEST benefit of a surgical aortic valve repair over aortic balloon valvuloplasty? \r\n”,”desc”:””,”hint”:””,”answers”:{“m2h7l”:{“id”:”m2h7l”,”image”:””,”imageId”:””,”title”:”A. Decreased rate of aortic valve replacement”},”olcn2″:{“id”:”olcn2″,”image”:””,”imageId”:””,”title”:”B. Increased survival rate”},”vt433″:{“id”:”vt433″,”image”:””,”imageId”:””,”title”:”C. Decreased long-term aortic insufficiency “,”isCorrect”:”1″},”8eogh”:{“id”:”8eogh”,”image”:””,”imageId”:””,”title”:”D. Decreased length of hospital stay”}}}},”results”:{“wqsr7”:{“id”:”wqsr7″,”title”:””,”image”:””,”imageId”:””,”min”:”0″,”max”:”1″,”desc”:”Congenital aortic stenosis occurs in approximately 6% of patients with congenital heart disease. While valvar aortic stenosis is most common, stenosis can occur at the subvalvar, valvar, or supravalvar level. Valvar aortic stenosis is more common in males, and is often associated with a bicuspid aortic valve, coarctation of the aorta, patent ductus arteriosus, and ventricular septal defect. Unicuspid aortic valve is most often associated with critical aortic stenosis. If not recognized early, neonates with severe aortic stenosis can present with congestive heart failure, arrhythmias, lactic acidosis, cardiogenic shock, and even sudden death. \r\n\r\nThe size and function of the left ventricle is the main determinant for appropriateness of a single-ventricle versus a biventricular repair. Measurements that predict a favorable two-ventricle repair include aortic annulus \u2265 3.0 cm\/m^{2<\/sup>, aortic root \u2265 3.5 cm\/m2<\/sup>, mitral valve area \u2265 4.75 cm2<\/sup>\/m2<\/sup>, ratio of long axis of the left ventricle to the heart \u22650.8, and left ventricular cross-sectional area \u2265 2.0 cm2<\/sup>. The most common interventions which preserve biventricular anatomy include balloon aortic valvuloplasty (BAV) and surgical aortic valvotomy (SAV). The goal of either intervention is to reduce the aortic valve gradient and prevent aortic regurgitation. \r\n\r\nBAV is performed in the cardiac catheterization lab. The aortic valve can be approached via the femoral, umbilical, or carotid arteries. It is recommended to use a balloon with a balloon to aortic valve annulus ratio of 0.8 to 1.0 to avoid over-dilation, which can result in significant aortic insufficiency (AI). A unicuspid aortic valve morphology is not always amenable to BAV due to increased risk of AI. After BAV, an immediate reduction in the peak pressure gradient across the valve is typically seen. The degree of immediate post-valvuloplasty insufficiency is predictive of late onset AI and suggests the likelihood for re-intervention. \r\n\r\nSAV is performed in the operating room with cardiopulmonary bypass, cardioplegia, and hypothermic myocardial protection. Early surgical techniques for SAV were associated with roughly 50% mortality. However, advancements in surgical technique have improved mortality to a 100% 10-year survival. If not amenable to SAV, a valve replacement with a prosthetic or allograft valve may be performed. Alternatively, the Ross procedure may be performed in which the patient\u2019s pulmonary valve replaces the aortic valve. Prerequisites to the Ross procedure include a normal right ventricular outflow tract and pulmonary valve. The disadvantage of the the Ross procedure is the risk of future aortic and pulmonary valve disease. \r\n\r\nEarly studies demonstrated equivocal outcomes in terms of survival and the need for re-intervention when comparing SAV and BAV. Advancements in surgical technique have demonstrated improved outcomes after SAV in more recent studies. In a study by Siddiqui et al, freedom from re-intervention at five years was 65% after SAV compared to 27% after BAV. Similar results were demonstrated in a meta-analysis by Hill et al in which BAV resulted in reduced gradient reduction, increased AI post-procedure, and greater need for subsequent intervention compared to SAV. Additionally, there was no difference in long-term survival and freedom from aortic valve replacement between the two groups, thus answer A is incorrect. The study also demonstrated a greater rate of additional intervention in the BAV group. \r\n\r\nA study by Hermann et al demonstrated that SAV resulted in greater gradient reduction, reduced long-term AI, and a lower re-intervention rate at 10 years compared to BAV. However, SAV has been associated with higher morbidity and longer hospital stay compared to BAV. Studies have demonstrated no difference in mortality between the two groups. As a result, in this question the correct answer is C because there is less long-term aortic insufficiency in the SAV group. There is no difference in survival or rate of valve replacement between the two groups. Patients undergoing SAV require a longer hospital stay. \r\n\r\nReferences: \r\n\r\nSpaeth JP and Loepke AW. Anesthesia for Left-sided Obstructive lesions. In: Andropoulos, D, Stayer S, Mossad EB, Miller-Hance WC. Anesthesia for Congenital Heart Disease<\/em>. Third Edition. Hoboken, New Jersey: John Wiley & Sons, Inc. 2015, 497-515. \r\n\r\nSingh, G. Congenital Aortic Valve Stenosis. Children (Basel)<\/em>. 2019; 6(5): 69. doi: 10.3390\/children6050069 \r\n\r\nHerrmann JH, Clark AJ, Colgate C, et al. Surgical valvuloplasty versus balloon dilation for congenital aortic stenosis in pediatric patients. World J Pediatr Congenit Heart Surg<\/em>. 2020; 11(4): 444-451. doi:10.1177\/2150135120918774. \r\n\r\nMcCrindle B, Blackson EH, Williams WG, et al. Are outcomes of surgical versus transcatheter balloon valvotomy equivalent in neonatal critical aortic stenosis? Circulation<\/em>. 2001; 104: I152-158. \r\n\r\nSiddiqui J, Brizard CP, Galati JC, et al. Surgical valvotomy and repair for neonatal and infant congenital aortic stenosis achieves better results than interventional catheterization. J Am Coll Cardiol<\/em>. 2013; 62(22): 2134-2140. doi:10.1016\/j.jacc.2013.07.052. \r\n\r\nHill G, Ginde S, Rios R, Frommelt PC, Hill KD. Surgical valvotomy versus balloon valvuloplasty for congenital aortic valve stenosis: A systematic review and meta-analysis. J Am Heart Assoc<\/em>. 2016; 5(8): e003931. doi: 10.1161\/JAHA.116.003931. \r\n\r\nBrown J, Rodefeld MD, Ruzmetov M, Eltayeb O, Yurdakok, Turrentine MW. Surgical valvuloplasty versus balloon aortic dilation for congenital aortic stenosis: Are evidence-based outcomes relevant? Ann Thorac Surg<\/em>. 2012; 94(1): 146-153. doi:10.1016\/j.athoracsur.2012.02.054. \r\n\r\n”,”redirect_url”:””}}}}

{“questions”:{“m0xg1”:{“id”:”m0xg1″,”mediaType”:”image”,”answerType”:”text”,”imageCredit”:””,”image”:””,”imageId”:””,”video”:””,”imagePlaceholder”:””,”imagePlaceholderId”:””,”title”:”Authors: Anna Hartzog MD and Chinwe Unegbu MD \u2013 Children\u2019s National Hospital \r\n\r\nA 4-day-old full term infant is diagnosed with Tetralogy of Fallot (TOF) with severe pulmonary stenosis. What is the MOST LIKELY reason to select a two-stage repair with an initial modified Blalock Taussig shunt (mBTS) instead of a complete repair with a transannular patch? \r\n\r\n”,”desc”:””,”hint”:””,”answers”:{“c7jk9”:{“id”:”c7jk9″,”image”:””,”imageId”:””,”title”:”A. Decreased need for transannular patch “},”utrdp”:{“id”:”utrdp”,”image”:””,”imageId”:””,”title”:”B. Improved long-term outcomes “},”7m71a”:{“id”:”7m71a”,”image”:””,”imageId”:””,”title”:”C. Institutional preference”,”isCorrect”:”1″},”b1wlo”:{“id”:”b1wlo”,”image”:””,”imageId”:””,”title”:”D. Decreased pulmonary artery distortion “}}}},”results”:{“y2qal”:{“id”:”y2qal”,”title”:””,”image”:””,”imageId”:””,”min”:”0″,”max”:”1″,”desc”:”Tetralogy of Fallot (TOF) is the most common form of cyanotic congenital heart disease. It is characterized by four distinct anatomic features described by Etienne Fallot in 1888 including the following: 1) anterior malalignment ventricular septal defect, 2) right ventricular outflow tract obstruction, 3) overriding aorta, and 4) right ventricular hypertrophy. The anterior malalignment of the conoventricular septum produces the spectrum of disease which can range in severity from an asymptomatic neonate to one that is severely cyanotic and has ductal-dependent physiology. The severity of the right ventricular outflow tract obstruction (RVOTO) determines the degree of cyanosis. Most commonly, cyanosis is mild at birth and gradually progresses with age as there is an increase in infundibular hypertrophy. By six to twelve months of life, the cyanosis tends to be significant. A smaller percentage of patients with TOF and pulmonary stenosis (PS) have marked cyanosis soon after birth. In this population, the RVOTO is often secondary to a hypoplastic pulmonary valve annulus and the cyanosis is constant because of the fixed nature of the obstruction to pulmonary blood flow. \r\n\r\nTraditionally, there have been two surgical approaches to Tetralogy of Fallot with pulmonary stenosis including primary complete repair versus a two-stage repair with an aortopulmonary shunt followed by a complete repair either with a transannular patch or a valve sparing procedure. At present, the ideal age for complete correction of TOF remains elusive and is highly institution dependent. Historically, the approach to a neonate or infant with TOF has been to wait for surgical repair until symptoms develop or until the infant was older. The morbidity and mortality of the operation was thought to be less in an older patient. \r\n\r\nAn early primary repair restores a normal circulation, which can diminish the deleterious physiologic effects of TOF to the heart, lungs, brain and other organ systems. Studies have shown that normalizing pulmonary arterial flow early optimizes pulmonary angiogenesis and alveolar development. Additionally, due to the unrestrictive anterior malalignment VSD, the right ventricle is exposed to systemic pressure resulting in right ventricular hypertrophy and decreased compliance. There is some evidence that left ventricular function is compromised as well when repair is delayed. There is a lower incidence of ventricular arrhythmias among children repaired at younger ages. An additional benefit of primary repair is the avoidance of aortopulmonary shunt related complications such as pulmonary artery distortion, shunt thrombosis, congestive heart failure, and\/or pulmonary vascular disease. Thus, answer choice B and D are incorrect. At present, there is essentially no contraindication to early primary repair. Historically, indications for delayed repair include an anomalous coronary artery crossing the right ventricular outflow tract, hypoplastic or discontinuous pulmonary arteries, and multiple VSDs. \r\n\r\n\r\nDespite success with early primary surgical repair of TOF, a two-stage repair remains favored at many institutions. Thus, answer choice C is correct. This is primarily the result of institutional culture, experience, and outcomes. An additional reason to delay complete repair in favor of two-stage repair revolves around the physiologic sequelae of a transannular patch over time, which includes increased ventricular dimensions, decreased ventricular function, decreased exercise capacity, arrhythmias, heart failure, and sudden cardiac death. However, there is insufficient evidence to support the idea that a two-stage repair decreases the risk of later pulmonary valve replacement. The largest published series describing late-phase events in adults with repaired TOF demonstrated that the risk of later reoperation is independent of the type of initial repair. Likewise, there is no evidence to suggest that initial palliation with an aortopulmonary shunt results in a decreased incidence of later complete repair with a transannular patch. Thus, answer choice A is incorrect. \r\n\r\n\r\nAl Habib et al. analyzed contemporary patterns of management of TOF\/PS using The Society of Thoracic Surgeons database and demonstrated that procedure type in neonates was equally divided between primary repair and a two-stage approach. In addition, use of a transannular patch was the most prevalent surgical technique for both primary repair and for a 2-stage repair. The discharge mortality from TOF repair in neonates was not significantly different between palliation (6.2%) and primary repair (7.8%). Thus, answer choice B is incorrect. Kanter et al. examined outcomes in neonates with symptomatic TOF who underwent either a primary repair or a two-stage repair and found equivalent mortality rates. Additionally, the study demonstrated that shunted patients had fewer transannular patch repairs but this has not been a consistent finding across studies. Antegrade pulmonary blood flow is the primary stimulus for growth of right ventricular outflow tract structures and thus a palliative aortopulmonary shunt would perpetuate reduced pulmonary flow. Thus, the expectation would be that the pulmonary valve would become smaller with time in patients with an aortopulmonary shunt and increase the need for a transannular patch. Nonetheless, the debate about the effect of early primary repair with a transannular patch on the growth of the pulmonary valve annulus remains a hot topic. \r\n\r\nReferences \r\n\r\n1.\tBarratt-Boyes BG, Neutze JM. Primary repair of Tetralogy of Fallot in infancy using profound hypothermia with circulatory arrest and limited cardiopulmonary bypass: a comparison with conventional two stage management. Ann Surg<\/em>. 1973; 178: 406\u2013411. \r\n\r\n2.\tCastaneda AR, Freed MD, Williams RG, Norwood WI. Repair of Tetralogy of Fallot in infancy: early and late results. J Thorac Cardiovasc Surg<\/em>. 1977; 74: 372\u2013381. \r\n\r\n3.\tDi Donato RM, Jonas RA, Lang P, Rome JJ, Mayer JE Jr, Castaneda AR. Neonatal repair of tetralogy of Fallot with and without pulmonary atresia. J Thorac Cardiovasc Surg<\/em>. 1991; 101(1):126-137. PMID: 1986154. \r\n\r\n4.\tSullivan ID, Presbitero P, Gooch VM, Arura E, Deanfield JE. Is ventricular arrhythmia in repaired tetralogy of Fallot an effect of operation or a consequence of the course of the disease? A prospective study. Br Heart J<\/em>. 1987; 58: 40\u201344.\r\n\r\n5.\tHegerty A, Anderson RH, Deanfield JE. Myocardial fibrosis in tetralogy of Fallot: effect of surgery or part of the natural history? Br Heart J<\/em>. 1988; 59: 123. \r\n\r\n6.\tJonas RA. Early primary repair of tetralogy of Fallot. Semin Thorac Cardiovasc Surg Pediatr Card Surg Annu<\/em>. 2009: 39-47.\r\n\r\n7.\tParry AJ, McElhinney DB, Kung GC, Reddy M, Brook MM, Hanley FL. Elective Primary Repair of Acyanotic Tetralogy of Fallot in Early Infancy: Overall Outcome and Impact on the Pulmonary Valve. J Am Coll Cardiol<\/em>. 2000; 36: 2279\u20132283. \r\n\r\n8.\tKirklin JW, Blackstone EH, Pacifico AD, Brown RN, Bargeron LM Jr. Routine primary repair vs two stage repair of tetralogy of Fallot. Circulation<\/em>. 1979; 60: 373\u2013386. \r\n\r\n9.\tVobecky SJ, Williams WG, Trusler GA, et al. Survival analysis of infants under age 18 months presenting with tetralogy of Fallot. Ann Thorac Surg<\/em>. 1993; 56: 944\u2013949. \r\n\r\n\r\n10.\tVan Arsdell GS, Maharaj GS, Tom J et al. What is the Optimal Age for Repair of Tetralogy of Fallot? Circulation<\/em>. 2000;102:Iii-123\u2013129. \r\n\r\n11.\tGladman G, McCrindle BW, Williams WG, et al. The modified Blalock-Taussig shunt: clinical impact and morbidity in Fallot\u2019s tetralogy in the current era. J Thorac Cardiovasc Surg<\/em>. 1997; 114: 25\u201330. \r\n\r\n12.\tUva MS, Chardigny C, Galetti L, et al. Surgery for tetralogy of Fallot at less than six months of age. Is palliation \”old-fashioned\u201d? Eur J Cardiothorac Surg<\/em>. 1995; 9(8): 453\u2013460. \r\n\r\n13.\tLee CH, Kwak JG, Lee C. Primary repair of symptomatic neonates with tetralogy of Fallot with or without pulmonary atresia. Korean J Pediatr<\/em>. 2014; 57(1): 19-25. doi: 10.3345\/kjp.2014.57.1.19. \r\n\r\n14.\tAl Habib HF, Jacobs JP, Mavroudis C, et al. Contemporary patterns of management of tetralogy of Fallot: data from the Society of Thoracic Surgeons Database. Ann Thorac Surg<\/em>. 2010; 90(3): 813-819. \r\n\r\n15.\tKanter KR, Kogon BE, Kirshbom PM, Carlock PR. Symptomatic neonatal tetralogy of Fallot: repair or shunt? Ann Thorac Surg<\/em>. 2010; 89(3): 858-863. \r\n\r\n16.\tGuyton RA, Owens JE, Waumett JD, Dooley KJ, Hatcher CR Jr, Williams WH. The Blalock-Taussig shunt. Low risk, effective palliation, and pulmonary artery growth. J Thorac Cardiovasc Surg<\/em>. 1983; 85(6): 917-922. \r\n\r\n17.\tPigula FA, Khalil PN, Mayer JE, del Nido PJ, Jonas RA. Repair of Tetralogy of Fallot in Neonates and Young Infants. Circulation<\/em>. 1999; 100: II-157\u2013161.\r\n\r\n\r\n”,”redirect_url”:””}}}

{“questions”:{“e6xx6”:{“id”:”e6xx6″,”mediaType”:”image”,”answerType”:”text”,”imageCredit”:””,”image”:””,”imageId”:””,”video”:””,”imagePlaceholder”:””,”imagePlaceholderId”:””,”title”:”Author: Anna Hartzog MD\u2013 Children\u2019s National Hospital, Chinwe Unegbu MD \u2013 Children\u2019s National Hospital \r\n\r\nA three-year-old male child with a history of heterotaxy and an unbalanced atrioventricular canal palliated with an extracardiac Fontan presents for cardiac catheterization. The catheterization angiograms demonstrate large collateral blood vessels from the bilateral internal mammary arteries. Which of the following is the MOST appropriate reason to use particle embolization instead of coil embolization to occlude collateral blood vessels?”,”desc”:””,”hint”:””,”answers”:{“a1piz”:{“id”:”a1piz”,”image”:””,”imageId”:””,”title”:”A. Decreased risk of systemic embolization”},”vu68v”:{“id”:”vu68v”,”image”:””,”imageId”:””,”title”:”B. More effective proximal occlusion of the feeder vessel”},”hnnjv”:{“id”:”hnnjv”,”image”:””,”imageId”:””,”title”:”C. Future catheterization of the feeder vessel is not compromised”,”isCorrect”:”1″},”1qtus”:{“id”:”1qtus”,”image”:””,”imageId”:””,”title”:”D. More effective occlusion of larger diameter feeder vessels”}}}},”results”:{“uwn5h”:{“id”:”uwn5h”,”title”:””,”image”:””,”imageId”:””,”min”:”0″,”max”:”1″,”desc”:”Aortopulmonary collaterals (APCs) are common in patients with single ventricle physiology,\r\noccurring in up to two-thirds of patients after the bidirectional Glenn procedure and one-half of\r\npatients after the Fontan procedure. These collaterals provide a source of blood from the\r\nsystemic arterial circulation to the pulmonary circulation resulting in recirculation of oxygenated\r\nblood through the pulmonary circulation and volume overload of the single ventricle. The\r\nmechanism as to how and the reason why collaterals develop is not understood completely.\r\nSome of the proposed triggers of APC formation include hypoxemia-induced angiogenesis,\r\nchronic chest wall inflammation, and small pulmonary artery (PA) size. The benefits provided by\r\naortopulmonary collateral blood supply include improved systemic oxygenation and pulmonary\r\nartery development and growth. However, the negative sequelae of volume overload to the single\r\nventricle includes single ventricle dilation and dysfunction, heart failure, and ineffective\r\npulmonary blood flow outweigh the potential benefits. Early studies did not demonstrate a\r\nbenefit of coiling APCs in patients prior to the Fontan nor a benefit in length of hospital stay\r\nfollowing the Fontan palliation. However, more recent studies have demonstrated that\r\nsignificant collateral burden is associated with prolonged pleural effusions, longer intensive care\r\nunit stays, and overall longer hospital stays. Studies have also demonstrated that pre-Fontan coil\r\nembolization has been associated with improved preoperative hemodynamics. \r\n\r\nTranscatheter thrombotic coil embolization has traditionally been utilized to occlude APCs as an\r\nalternative to surgical exposure and ligation. Often these collaterals are difficult to locate and\r\nsurgically transected due to their location which could potentially prolong operative time and\r\nlead to increased blood loss. As such, transcatheter occlusion of collaterals in the cardiac\r\ncatheterization lab has proven to be an advantageous alternative. Coils are often composed of\r\nsteel or platinum and are sometimes embedded with fibers that promote thrombosis. They are\r\navailable in many different diameters and lengths. They serve to provide mechanical occlusion\r\nand promote occlusion of collaterals through thrombosis. Coils are typically inserted into\r\nproximal normal-caliber systemic arteries that supply the collateral vessels, which serves to limit\r\ncollateral blood flow, left to right shunting, and volume overload. However, coil embolization of\r\nthe proximal systemic arterial supply does not occlude the collateral vessels themselves. Thus,\r\nthe collateral vessels are left intact for possible future vascular supply from either the same or\r\nnew \u201cfeeding\u201d blood vessels. Additionally, placement of coils into proximal systemic arteries\r\ndoes prohibit further access to those particular vessels during future cardiac catherization\r\nprocedures. \r\n\r\nParticle embolization is a newer technique utilized for APC occlusion that may provide more\r\nefficient distal embolization by targeting smaller arteries and more distal arterioles. Thus larger\r\n\u201cfeeding\u201d arteries are left intact, allowing future access with catheterization. The most common\r\nmaterials for particle embolization include polyvinyl alcohol (PVA) microparticles and tris-acryl\r\ngelatin microspheres (TAGM). APC occlusion is due to thrombus formation around the PVA\r\nparticles. While PVA particles themselves are non-absorbable, surrounding clot may dissolve\r\nafter a few weeks, and the vessels may recanalize. Due to the small size of both PVA and TAGM\r\nparticles, there is a significant risk of systemic embolization, especially if deployed into larger\r\ncaliber vessels. Systemic embolization into a vessel supplying the central nervous system can\r\nlead to stroke and spinal cord injury. Particular vessels to avoid include the vertebral and carotid\r\narteries as well as the artery of Adamkiewicz. It is imperative to perform frequent neurovascular\r\nexams in the initial post-catheterization period. \r\n\r\nChoice C is the correct answer; particle embolization occludes vessels more distally and does not\r\nocclude the proximal \u201cfeeding\u201d vessel. Choice A is incorrect as particle embolization poses a\r\nhigher risk of systemic embolization due to small particle size. Choice B and D are incorrect\r\nbecause coil embolization is more effective for occlusion of more proximal and larger diameter\r\nvessels. \r\n\r\nReferences \r\n1. Prakash, A. Significance of systemic to pulmonary artery collaterals in single ventricle\r\nphysiology: new insights from CMR imaging. Heart<\/em>. 2012; 98(12): 897-899. \r\n2. Banka P, Sleeper LA, Atz AM, et al. Practice Variability and Outcomes of Coil\r\nEmbolization of Aortopulmonary Collaterals Prior to Fontan Completion: A Report from\r\nthe Pediatric Heart Network Fontan Cross-Sectional Study. Am Heart J<\/em>. 2011; 162(1):\r\n125\u2013130. \r\n3. Latus H, Gummel K, Diederichs T, et al. Aortopulmonary Collateral Flow Is Related to\r\nPulmonary Artery Size and Affects Ventricular Dimensions in Patients after the Fontan\r\nProcedure. PLoS One<\/em>. 2013; 8(11): e81684. \r\n4. Batlivala S, Briscoe W, and Ebeid M. Particle embolization of systemic-to-pulmonary\r\ncollateral artery networks in congenital heart disease: Technique and special\r\nconsiderations. Ann Pediatr Cardiol<\/em>. 2018; 11(2): 181-186. \r\n5. O\u2019Bryne M, Schidlow D. Durable Benefit of Particle Occlusion of Systemic to\r\nPulmonary Collaterals in Select Patients After Superior Cavopulmonary Connection.\r\nPediatr Cardiol<\/em>. 2018; 39(2): 245-253. \r\n6. Dori Y, Glatz AC, Hanna BD, et al. Acute Effects of Embolizing Systemic-to-Pulmonary\r\nArterial Collaterals on Blood Flow in Patients With Cavopulmonary Connections: A Pilot\r\nStudy. Circ Cardiovasc Interv<\/em>. 2013; 6(1): 101-106. \r\n7. Sim J, Aleijos J, and Moore J. Techniques and Applications of Transcatheter\r\nEmbolization Procedures in Pediatric Cardiology. J Interv Cardiol<\/em>. 2003; 6(5): 425-448. \r\n\r\n\r\n”,”redirect_url”:””}}}

{“questions”:{“ld468”:{“id”:”ld468″,”mediaType”:”image”,”answerType”:”text”,”imageCredit”:””,”image”:””,”imageId”:””,”video”:””,”imagePlaceholder”:””,”imagePlaceholderId”:””,”title”:”Author: Anna Hartzog MD\u2013 Children\u2019s National Hospital, Chinwe Unegbu MD \u2013 Children\u2019s National Hospital \r\n\r\nA 3-month-old male with Tetralogy of Fallot (TOF) with worsening cyanosis presents for surgical repair with infundibular muscle bundle resection and a transannular patch. Preoperatively, the patient has been on propranolol and his baseline heart rate is 120. Prior to separation from bypass, dopamine is started at 10 mcg\/kg\/min, the rectal temperature is 35.5 degrees Celsius, and the magnesium level is 2.1 mg\/dL. Upon separation from cardiopulmonary bypass (CPB), junctional ectopic tachycardia (JET) is noted with hemodynamic instability. What is the MOST LIKELY contributing factor to JET in this patient?\r\n”,”desc”:””,”hint”:””,”answers”:{“y7z7y”:{“id”:”y7z7y”,”image”:””,”imageId”:””,”title”:”A. Preoperative heart rate “},”64v8r”:{“id”:”64v8r”,”image”:””,”imageId”:””,”title”:”B. Intraoperative magnesium level”},”fab9v”:{“id”:”fab9v”,”image”:””,”imageId”:””,”title”:”C. Intraoperative inotropic requirement”,”isCorrect”:”1″},”70f49″:{“id”:”70f49″,”image”:””,”imageId”:””,”title”:”D. Rewarming target temperature”}}}},”results”:{“3cpjt”:{“id”:”3cpjt”,”title”:””,”image”:””,”imageId”:””,”min”:”0″,”max”:”1″,”desc”:”Junctional ectopic tachycardia (JET) is the most common tachyarrhythmia in the postoperative period in children undergoing congenital heart surgery. The reported incidence following pediatric cardiac surgery ranges widely from 2-22%, which is due to differences in study design and the diversity of cardiac lesions represented in those studies. \r\n\r\nCongenital heart defects that are known to be major contributors to postoperative JET include ventricular septal defect (VSD), Tetralogy of Fallot (TOF), and complete atrioventricular canal (CAVC). The incidence of JET is greater when the surgical intervention is in close proximity to the atrioventricular (AV) node and bundle of His, as is the case with TOF and CAVC repair. TOF repair is widely recognized as the surgical procedure most likely to be associated with the development of postoperative JET. The reported incidence of JET following TOF repair varies from 4 to 37% in the literature. A 2018 study by Paluszek et al. reported the incidence of JET in pediatric patients following TOF repair to be 13.3%. \r\n\r\n\r\nEarly postoperative JET typically occurs within the first forty-eight hours after pediatric cardiac surgery and is defined as a narrow complex tachycardia with a rate of \u2265 170 bpm. JET originates from the atrioventricular (AV) node or AV junction, which includes the bundle of His. There is often AV dissociation resulting in the ventricular rate exceeding the atrial rate but sometimes there is 1:1 retrograde ventriculoatrial conduction. JET typically manifests with a narrow QRS complex; however, if a bundle branch block is present, then the QRS complex may be wide. The exact etiology of JET is unknown; however, many hypothesize that JET may be the result of direct mechanical trauma (ie surgical sutures) or indirect stretch injury with or without edema to the conduction system which then precipitates automaticity of the AV node\/bundle of His. \r\n\r\n\r\nDespite generally being a self-limiting condition, JET can be associated with postoperative hemodynamic instability and morbidity due to hemodynamic deterioration secondary to extreme tachycardia, loss of AV synchrony, and compromised ventricular filling. In particular, the combination of JET and depressed myocardial function may result in a low cardiac output state and cardiogenic shock. \r\n\r\n\r\nRisk factors for postoperative JET include an increased baseline preoperative heart rate, cyanotic spells, non-use of beta-blockers in the preoperative period, low intraoperative magnesium and calcium levels, prolonged cardiopulmonary bypass (CPB) and\/or aortic cross clamp times, hypothermic circulatory arrest, increased complexity of the surgical procedure, and use of high dose inotropes. Postoperative JET is also associated with a younger age at the time of operation and lower body weight. Younger patients presenting for surgical repair have smaller hearts that are more prone to mechanical or stretch related injury of the conduction system. Both postoperative inotropic score and dopamine use have been independently associated with the occurrence of postoperative JET. This suggests that JET may be triggered by the arrhythmogenic properties of dopamine. \r\n\r\n\r\nInterventions known to reduce the occurrence of JET after pediatric cardiac surgery include minimization of CPB and aortic cross clamp time, correction of electrolyte imbalances especially magnesium and calcium, use of magnesium sulfate on CPB, optimization\/titration of inotropic support with the goal of minimizing exogenous catecholamines, correction of intravascular volume, avoidance of hyperthermia, and adequate use of sedatives and analgesics. Some patients with JET require external pacing to restore AV synchrony. Many antiarrhythmics have been used in the management of JET, including but not limited to digoxin, sotalol, procainamide, and amiodarone. No single antiarrhythmic has been found to be superior. Typically, the antiarrhythmic initiated is simply a matter of institutional preference. \r\n\r\n\r\nIn this question stem, the most likely contributing factor to JET is the use of dopamine. The use of propranolol preoperatively suggests heart rate control and should be preventative against JET. Likewise, the magnesium level prior to separation from CPB was within normal limits and would be preventative as well. The rewarming target temperature of 35.5 is appropriately low and preventative to hyperthermia induced JET. \r\n\r\n\r\nReferences \r\n\r\n1.\tAl-Sofyani KA, Jamalaldeen RI, Abusaif SM, Elassal AA, Al-Radi OO. The prevalence and outcome of junctional ectopic tachycardia in pediatric cardiac surgery: Journal of the Egyptian Society of Cardio-Thoracic Surgery<\/em>. 2017; 25(2): 128-132. \r\n\r\n2.\tPaluszek C, Brenner P, Pichlmaier M, et al. Risk Factors and Outcome of Post Fallot Repair Junctional Ectopic Tachycardia (JET): World J Pediatr Congenit Heart Surg<\/em>. 2019; 10(1): 50-57. doi: 10.1177\/2150135118813124. PMID: 30799715. \r\n\r\n\r\n3.\tDodge-Khatami A, Miller OI, Anderson RH, et al. Surgical substrates of postoperative junctional ectopic tachycardia in congenital heart defects. J Thorac Cardiovasc Surg<\/em>. 2002; 123(4): 624-630. \r\n\r\n4.\tIsmail MF, Arafat AA, Hamouda TE, et al. Junctional ectopic tachycardia following tetralogy of fallot repair in children under 2 years. J Cardiothorac Surg<\/em>. 2018; 13(1): 60. doi:10.1186\/s13019-018-0749-y \r\n\r\n5.\tManrique AM, Arroyo M, Lin Y, et al. Magnesium supplementation during cardiopulmonary bypass to prevent junctional ectopic tachycardia after pediatric cardiac surgery: a randomized controlled study. J Thorac Cardiovasc Surg<\/em>. 2010; 139: 162-169. \r\n\r\n6.\tEl Amrousy D, Elshehaby W, Elfeky W, Elshmaa N. Safety and efficacy of prophylactic amiodarone in preventing early junctional ectopic tachycardia (JET) in children after cardiac surgery and determination of its risk factor. Pediatr Cardiol<\/em>. 2016; 37: 734\u2013739.\r\n\r\n\r\n\r\n\r\n\r\n”,”redirect_url”:””}}}