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

{“questions”:{“bmvzk”:{“id”:”bmvzk”,”mediaType”:”image”,”answerType”:”text”,”imageCredit”:””,”image”:””,”imageId”:””,”video”:””,”imagePlaceholder”:””,”imagePlaceholderId”:””,”title”:”Authors: Gokul Thimmarayan, MD and Destiny F. Chau, MD – Arkansas Children\u2019s Hospital \/University of Arkansas for Medical Sciences, Little Rock, AR \r\n\r\nAn 18-month-old toddler with a history of Trisomy 21 is undergoing a full repair of a partial atrioventricular canal with cardiopulmonary bypass. Ten times the intended dose of tranexamic acid is administered during the procedure in error. In the early post-operative period, generalized tonic-clonic seizures are noted. Tranexamic acid induces seizures by the competitive antagonism of which of the following receptors?\r\n”,”desc”:”EXPLANATION \r\nTranexamic acid (TXA) is an analog of lysine, which binds to plasminogen and prevents its conversion to plasmin, thereby inhibiting fibrinolysis and improving hemostasis. TXA use decreases the risk of bleeding after cardiac surgery with cardiopulmonary bypass in both the adult and pediatric populations. Epsilon aminocaproic acid (EACA), another lysine derivative, and aprotinin, a serine protease inhibitor, are other antifibrinolytic agents. \r\n \r\nThe reported dosing ranges and protocols for TXA differ greatly from a 10 to 100 mg\/kg bolus prior to cardiopulmonary bypass (CPB) followed by an infusion at variable rates and\/or an additional bolus in the pump prime. TXA use has been associated with an increased risk of thromboembolism, seizure, and renal dysfunction. Seizure frequency is correlated positively with higher doses of TXA (total TXA dose of >100 mg\/kg), which was demonstrated in study of adult cardiac surgical patients by Kalavrouziotis et al. TXA-related seizures are most frequently reported in the early postoperative period after cardiac surgery and are associated with increased morbidity and mortality. In a propensity-score matched study of 3,739 pairs of pediatric patients undergoing cardiac surgery, Maeda et al. demonstrated an incidence of seizures of 1.6% in the patients treated with TXA versus 0.2% in those not treated with TXA.\r\n\r\n \r\nA 2012 study by Lecker et al. used the mouse neuron as a model to investigate the mechanism of seizure due to TXA. The study demonstrated that TXA, which is a structural analog of the inhibitory neurotransmitter glycine, competitively binds to and inhibits the activity of glycine receptors. Thus, the authors postulated that blockade of inhibitory glycine receptors by TXA leads to neuronal hyperexcitability and lowers seizure threshold. The authors temporally measured the TXA concentration in serum and cerebrospinal fluid (CSF) in patients undergoing vascular surgery or cardiac surgery with cardiopulmonary bypass. The authors found that the peak TXA concentration in CSF occurs after<\/em> the peak TXA concentration in serum. The peak concentration of TXA in CSF correlated with the reported observation that seizures occur more frequently in the early postoperative period. This time frame also coincides with the waning anti-convulsant effects of general anesthetic agents after surgery. The authors also postulated that enhancing glycine inhibitory potential could suppress seizures associated with TXA. Therefore, agents such as isoflurane, sevoflurane, and propofol, which are known to stimulate glycine receptor activity, could potentially be used to prevent or treat seizures induced by TXA. \r\n\r\nEACA, which is also an analogue of lysine, is associated with a much lower incidence of seizures because it is a much weaker inhibitor at glycine receptors than TXA. In a study comparing the incidence of seizures in adult cardiac surgical patients treated with TXA or EACA, Martin et al. reported an incidence of 7.6% in the TXA group versus 3.3% in the EACA group. \r\n\r\nAspartate, and acetylcholine are excitatory neurotransmitters in the central nervous system. Thus far, they have not been associated with seizures caused by TXA. \r\n\r\nThe most effective way to prevent TXA-induced seizures is by utilizing doses at the lower end of the range known to be effective in reducing blood loss after surgery and by lowering the dose administered to patients with renal dysfunction, as it is primarily eliminated in the urine. Currently, there is not a clearly defined safe, yet effective dose of TXA. \r\n \r\nREFERENCES \r\n\r\nMaeda T, Sasabuchi Y, Matsui H, Ohnishi Y, Miyata S, Yasunaga H. Safety of tranexamic acid in pediatric cardiac surgery: a nationwide database study. J Cardiothorac Vasc Anesth <\/em>. 2017;31(2):549-553. doi:10.1053\/j.jvca.2016.10.001 \r\n\r\nLecker I, Wang DS, Romaschin AD, Peterson M, Mazer CD, Orser BA. Tranexamic acid concentrations associated with human seizures inhibit glycine receptors.J Clin Invest<\/em>. 2012;122(12):4654-4666. doi:10.1172\/JCI63375 \r\n\r\nKalavrouziotis D, Voisine P, Mohammadi S, Dionne S, Dagenais F. High-dose tranexamic acid is an independent predictor of early seizure after cardiopulmonary bypass. Ann Thorac Surg <\/em>. 2012;93(1):148-155. doi: 10.1016\/j.athoracsur.2011.07.085 \r\n\r\nLecker I, Wang D, Whissell P, Avramescu S, Mazer C, Orser B. Tranexamic acid-associated seizures: causes and treatment. Ann Neurol <\/em>. 2016;79(1):18-26. Doi:10.1002\/ama.24558 \r\n\r\nMartin K, Knorr J, Breur T et al. Seizures after open heart surgery: a comparison of E-aminocaproic acid versus tranexamic acid. J Cardiothorac Vasc Anesth<\/em>. 2011;25:20-5. doi: 10.1053\/j.jvca.2010.10.007.\r\n\r\n”,”hint”:””,”answers”:{“zzf35”:{“id”:”zzf35″,”image”:””,”imageId”:””,”title”:”A.\tAspartate”},”4o24p”:{“id”:”4o24p”,”image”:””,”imageId”:””,”title”:”B.\tGlycine”,”isCorrect”:”1″},”2ngc9″:{“id”:”2ngc9″,”image”:””,”imageId”:””,”title”:”C.\tAcetylcholine”}}}}}

{“questions”:{“8td7c”:{“id”:”8td7c”,”mediaType”:”image”,”answerType”:”text”,”imageCredit”:””,”image”:””,”imageId”:””,”video”:””,”imagePlaceholder”:””,”imagePlaceholderId”:””,”title”:”Authors: Destiny F. Chau, MD and Jorge Guerrero, MD – Arkansas Children\u2019s Hospital \/University of Arkansas for Medical Sciences, Little Rock, AR \r\n\r\nA 9 y\/o female child with a history of an extracardiac fenestrated Fontan presents for tonsillectomy and adenoidectomy. A recent cardiac catheterization demonstrated a Fontan pressure of 19 mmHg. Home medications include aspirin and sacubitril\/valsartan. Which class of medication does sacubitril belong to? \r\n”,”desc”:”EXPLANATION \r\nSacubitril is a neprilysin inhibitor, which is a naturally occurring endopeptidase enzyme that degrades neuropeptides that are known to contribute to the pathophysiology of heart failure. Chronic heart failure is associated with elevated neprilysin levels and faster clearance of neuropeptides. \r\n\r\nHeart failure results in the activation of both the sympathetic nervous system and the renin-angiotensin-aldosterone system leading to increased levels of renin, angiotensin II, aldosterone, and anti-diuretic hormone. The end result is increased vascular tone and blood pressure, which are compensatory mechanisms to increase organ perfusion. However, this activation impairs the function of endogenous neuropeptides such as atrial natriuretic peptide and B-type natriuretic peptide, bradykinin, and adrenomedullin. These peptides cause vasodilation, natriuresis, diuresis, and counteract the abnormal sympathetic response implicated in maladaptive vascular and cardiac remodeling. \r\n\r\nThe inhibition of neprilysin prevents the degradation of endogenous neuropeptides leading to an increased concentration of bradykinin, natriuretic peptides, adrenomedullin and angiotensin II. Therefore, a neprilysin inhibitor is paired with an angiotensin receptor blocker (ARB) to mitigate the effects of elevated angiotensin II levels. This class of drug, termed an ARNI (angiotensin receptor neprilysin inhibitor), received FDA approval in 2015 for the treatment of symptomatic heart failure with reduced ejection fraction. Patients must demonstrate tolerability to an angiotensin-converting enzyme inhibitor (ACEI) or ARB before starting sacubitril\/valsartan. \r\n\r\nAngiotensin II effects can reduced by using an ACEI. However, the combination of both a neprilysin inhibitor and an ACEI was found to cause significant angioedema due to the fact that both drugs increase bradykinin levels thus worsening angioedema. Therefore, the combination of an ACEI and ARNI should be avoided. Coadministration of a neprilysin inhibitor within 36 hours of an ACEI is contraindicated.\r\nIn a prospective, randomized trial by McMurray et al. (widely known as PARADIGM-HF – Prospective Comparison of ARNI [Angiotensin Receptor\u2013Neprilysin Inhibitor] with ACEI [Angiotensin-Converting\u2013Enzyme Inhibitor] to Determine Impact on Global Mortality and Morbidity in Heart Failure Trial) of adult patients with symptomatic heart failure and reduced ejection fraction, the use of sacubitril\/valsartan demonstrated increased efficacy in reducing morbidity and mortality versus standard treatment with enalapril. Adverse effects of sacubitril\/valsartan included hypotension, hyperkalemia, renal failure, cough, and angioedema. Compared to enalapril, treatment with sacubitril\/valsartan resulted in a higher incidence of hypotension and symptomatic hypotension but a lower risk of increased serum potassium and creatinine and lower risk of cough. Although not statistically significant, angioedema in the sacubitril\/valsartan group was higher than in the enalapril group, with no reported cases of angioedema causing airway compromise. \r\n\r\nAccording to the most recent 2022 AHA\/ACC\/HFSA guidelines (Heidenreich et al.), treatment with sacubitril\/valsartan is a Class I recommendation for the management of symptomatic heart failure with reduced ejection fraction. Additionally, treatment with sacubitril\/valsartan is a Class 2b recommendation for the management of heart failure with preserved ejection fraction. This drug is also known to enhance right sided ejection fraction and reduce pulmonary artery pressures independent of an improvement in left ventricular function. Sacubitril\/valsartan use in pediatric patients is based upon data from the adult population. However, there are current ongoing studies in the pediatric population. \r\n\r\nThe effect of general anesthesia on the blood pressure of patients taking an ARNI is currently unknown. Given the presence of an ARB in this combination drug and the reports of a higher risk of hypotension with ARNI use as compared to enalapril, it is reasonable to deduce that ARNI use may also be associated with severe refractory hypotension under general anesthesia. Therefore, vigilance and preparation for severe hypotension in patients taking an ARNI whilst undergoing general anesthesia is warranted. As of yet, there are no guidelines on how to best manage perioperative ARNI use. \r\n\r\n \r\nREERENCES \r\nMcMurray JJV, Packer M, Desai AS et al. Angiotensin-Neprolysin inhibition versus enalapril in heart failure. N Engl J Med. 2014; 371:993-1004. DOI: 10.1056\/NEJMoa1409077 \r\n\r\nHeidenreich PA, Bozkurt B, Aguilar D, et al. 2022 AHA\/ACC\/HFSA Guideline for the management of heart failure: A Report of the American College of Cardiology\/American Heart Association Joint Committee on Clinical Practice Guidelines [published correction appears in Circulation. 2022 May 3;145(18):e1033] [published correction appears in Circulation. 2022 Sep 27;146(13):e185] [published correction appears in Circulation. 2023 Apr 4;147(14):e674]. Circulation<\/em>. 2022;145(18):e895-e1032. doi:10.1161\/CIR.0000000000001063\r\n\r\nDas BB, Scholl F, Vandale B, Chrisant M. Sacubitril\/Valsartan: potential treatment for paediatric heart failure. Cardiol Young<\/em>. 2018;28(9):1077-1081. doi:10.1017\/S1047951118001014 \r\n\t\r\nNicolas D, Kerndt CC, Reed M. Sacubitril\/Valsartan. [Updated 2022 May 26]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https:\/\/www.ncbi.nlm.nih.gov\/books\/NBK507904\/ \r\n\r\nZhang J, Du L, Qin X, Guo X. Effect of sacubitril\/valsartan on the right ventricular function and pulmonary hypertension in patients with heart failure with reduced ejection fraction: a systematic review and meta-analysis of observational studies. J Am Heart Assoc<\/em>. 2022;11(9):e024449doi:10.1161\/JAHA.121.024449\r\n”,”hint”:””,”answers”:{“xzyl1”:{“id”:”xzyl1″,”image”:””,”imageId”:””,”title”:”A.\tNeprilysin inhibitor”,”isCorrect”:”1″},”pxwle”:{“id”:”pxwle”,”image”:””,”imageId”:””,”title”:”B.\tAngiotensin converting enzyme inhibitor”},”anjbt”:{“id”:”anjbt”,”image”:””,”imageId”:””,”title”:”C.\tPhosphodiesterase inhibitor”},”r5utx”:{“id”:”r5utx”,”image”:””,”imageId”:””,”title”:”D.\tCalcium channel blocker”}}}}}

{“questions”:{“xv60e”:{“id”:”xv60e”,”mediaType”:”image”,”answerType”:”text”,”imageCredit”:””,”image”:””,”imageId”:””,”video”:””,”imagePlaceholder”:””,”imagePlaceholderId”:””,”title”:”Authors: Dylan Trujillo, DO, Felipe Medeiros, MD, Destiny F. Chau, MD – Arkansas Children\u2019s Hospital \/University of Arkansas for Medical Sciences, Little Rock, AR \r\n\r\nTwo weeks following orthotopic heart transplantation for dilated cardiomyopathy, a 6-month-old male infant returns to the operating room for permanent pacemaker implantation. Which of the following is the MOST likely indication for permanent pacemaker implantation in this patient?\r\n\r\n”,”desc”:”EXPLANATION \r\nDysrhythmia following orthotopic heart transplantation (OHT) occurs in approximately 40% of pediatric recipients. Factors predisposing to dysrhythmia are multifactorial. One contributing factor relates to unopposed sympathetic tone secondary to donor heart denervation. Denervation leads to a lack of response to the modulating influence of the vagus nerve and to the higher baseline heart rate. Surgical techniques employed for orthotopic heart transplantation have also been implicated in the development of dysrhythmia. The biatrial technique preserves part of the recipient\u2019s right and left atrial tissue to facilitate the incorporation of the cardiac graft. The bicaval technique incorporates a cuff of the recipient\u2019s left atrial tissue. Scarring of the atria creates a predisposition to atrial flutter. In the biatrial method, P waves may be generated from both the cardiac graft and native atrial tissue which mimics atrial flutter. Additionally, sinus node activity from native atrial tissue may be conducted intermittently and thus manifest as ectopic atrial beats. As cuffs of atrial tissue are preserved in both techniques, all patients are expected to develop some degree of increased atrial size after OHT. Other factors which contribute to the risk of dysrhythmia after OHT include prolonged graft ischemic time, donor-recipient size mismatching (which contributes to atrial enlargement), acute and chronic rejection, and cardiac allograft vasculopathy. \r\n\r\nAtrial fibrillation and atrial flutter have been reported in 10% to 25% of patients after OHT with the majority of cases occurring in the first few weeks after transplantation and with eventual resolution in the majority of patients. Bradydysrhythmias occurring after OHT (which also frequently resolve spontaneously) include atrioventricular block and sinus bradycardia. Common causes include sinus node injury or ischemia, sympathetic denervation, and medication side effects. \r\nTemporary pacing for bradydysrhythmia is often utilized following OHT while the cardiac conduction system recovers from injury. Rarely, when normal cardiac conduction does not return, consideration of permanent pacemaker implantation is necessary. The 2021 PACES expert consensus on pediatric cardiovascular implantable electronic devices recommends waiting at least one week for spontaneous recovery of sinus node function. \r\nA systematic review of 11 studies by Mylonas et al. which included a total of 7,198 pediatric patients who underwent heart transplantation demonstrated that 1.9% of patients received a permanent pacemaker. However, although overall sinus node dysfunction was the most frequent indication for pacemaker placement (54.4% versus 45.6% for complete atrioventricular block), in almost half of the cases there was no indication reported. The need for pacemaker placement occurred earlier in the postoperative course in patients with complete atrioventricular block. The median time interval between OHT and permanent pacemaker implantation ranged from 17 days to 6.5 years in patients with complete heart block while it was 2.7 months to 12.5 years for sinus node dysfunction. The biatrial technique was utilized in 62.2% of patients and the bicaval technique in the remaining 37.8%. \r\n\r\nIn a single-center study by Mahmood et al., of 314 pediatric transplant recipients, 16 (5.1%) patients required permanent pacemaker placement. Indications for pacemaker placement were complete heart block in 75% of patients and sinus node dysfunction in 25% of patients. In 9 of 12 (75%) patients with complete heart block, the pacemaker was implanted within 21 days of the transplant. Three out of the four patients with sinus node dysfunction had pacemaker implantation at 61 days or longer after transplant. \r\nThe patient described in the question stem has undergone OHT two weeks prior without restoration of normal sinus rhythm and is most likely to have persistent complete atrioventricular block given the described time frame. Although symptomatic sinus bradycardia and second degree Mobitz Type II heart block can occur, they either resolve or persist to meet the indication for permanent pacemaker implantation at a later timepoint as compared to complete heartblock. At this early stage after OHT, close evaluation is important to rule out reversible causes of bradydysrhythmia such as acute rejection or antiarrhythmic medication side effects. \r\nREFERENCES \r\n\r\nNavas-Blanco JR, Modak RK. Perioperative care of heart transplant recipients undergoing non-cardiac surgery. Ann Card Anaesth<\/em>. 2021;24(2):141-148 doi: 10.4103\/aca.ACA_130_19. \r\n\r\n\r\nJoglar JA, Wan EY, Chung MK, et al. Management of arrhythmias after heart transplant: current\r\nstate and considerations for future research. Circ Arrhythm Electrophysiol <\/em>.2021;14(3):e007954. doi: 10.1161\/CIRCEP.120.007954. \r\n\r\nShah MJ, Silka MJ, Silva JNA, et al. 2021 PACES expert consensus statement on the indications and management of cardiovascular implantable electronic devices in pediatric patients. Cardiol Young<\/em>. 2021;31(11):1738-1769. doi:10.1017\/S1047951121003413\r\n\r\nMylonas KS, Repanas T, Athanasiadis DI, et al. Permanent pacemaker implantation in pediatric heart transplant recipients: A systematic review and evidence quality assessment. Pediatr Transplant<\/em>. 2020;24(3):e13698. doi: 10.1111\/petr.13698. \r\nMahmood A, Andrews R, Fenton M et al. Permanent pacemaker implantation after pediatric heart transplantation: Risk factors, indications, and outcomes. Clin Transplant <\/em>.2019;33(4) e13503. doi: 10.1111\/ctr.13503.\r\nHerrmann FEM, Wellmann P, Hagl C, Juchem G. Pediatric heart transplantation-What are the risk factors for pacemaker implantation and how much pacing is required? Pacing Clin Electrophysiol<\/em>. 2018;41(3):267-276. doi: 10.1111\/pace.13276.\r\n\r\n\r\n\r\n\r\n\r\n”,”hint”:””,”answers”:{“cl5cs”:{“id”:”cl5cs”,”image”:””,”imageId”:””,”title”:”A.\tComplete atrioventricular block “,”isCorrect”:”1″},”7mfo2″:{“id”:”7mfo2″,”image”:””,”imageId”:””,”title”:”B.\tSecond Degree (Mobitz) type II heart block”},”7278l”:{“id”:”7278l”,”image”:””,”imageId”:””,”title”:”C.\tSymptomatic sinus bradycardia “}}}}}

{“questions”:{“6ntww”:{“id”:”6ntww”,”mediaType”:”image”,”answerType”:”text”,”imageCredit”:””,”image”:””,”imageId”:””,”video”:””,”imagePlaceholder”:””,”imagePlaceholderId”:””,”title”:”Authors: Dylan Trujillo, DO, Felipe Medeiros, MD, Destiny F. Chau, MD; Arkansas Children\u2019s Hospital\/University of Arkansas for Medical Sciences, Little Rock, AR \r\n\r\nAn 8-year-old male child with history of an orthotopic heart transplantation six years prior due to dilated cardiomyopathy presents for laparoscopic appendectomy. The patient is compliant with transplant medications and the last cardiac catheterization demonstrated normal hemodynamics without rejection. The vital signs are as follows: BP 97\/55, HR 108, SpO2 99% in room air, RR 21, and T 37.8^{o<\/sup>C. Laboratory results show: WBC 18 x 109 <\/sup>\/L, Hb 13 g\/dL, platelets 245 x 109 <\/sup>\/L. At present, which of the following is the MOST likely cause of morbidity and mortality in this patient?\r\n\r\n\r\n”,”desc”:”EXPLANATION \r\nThe primary causes of mortality following orthotopic heart transplantation (OHT) vary with the time elapsed since transplant. Common causes of death include acute rejection, infection, cardiac allograft vasculopathy (CAV) and malignancy. While acute rejection is the leading cause of death during the first 3 years following OHT, CAV predominates thereafter as the leading cause of mortality. \r\n\r\nAccording to data from the International Society of Heart and Lung Transplantation, approximately 20% of OHT recipients have some degree of CAV at 5 years and 25% at 10 years post-transplant. The mortality rate after CAV diagnosis is high across all age groups. There is 25% 2-year mortality in patients with any severity of CAV and 50% 2-year mortality in patients with moderate-to-severe CAV. Infants have the worst survival rates with a median of 2 years after CAV diagnosis. The clinical symptom of chest pain from myocardial ischemia is typically absent due to denervation of the transplanted heart. Therefore, severe CAV manifests as progressive deterioration in graft function, heart failure, or sudden death. For this reason, transplant recipients are usually screened on a yearly basis for CAV using coronary angiography or dobutamine stress echocardiography. The histologic appearance of CAV is that of concentric intimal and medial proliferation that ultimately results in luminal occlusion, diastolic dysfunction, and graft failure. Treatment of CAV includes percutaneous revascularization procedures such as balloon angioplasty and coronary artery stenting, but the success rate is low due to the diffuse nature of the disease. Cardiac re-transplantation should be considered for those patients with moderate to severe CAV and graft dysfunction. \r\n\r\nThe rate of infection in OHT patients is highest in the first year after transplantation, accounting for approximately 16% of deaths, but declines thereafter. As immunosuppressive therapy can potentiate the severity of infections, early diagnosis and aggressive therapy of infection is imperative. In a 2006 single institution, retrospective review by Savar et al. of 8000 solid organ transplants (which included four OHTs and one heart-kidney transplant), 17 patients underwent appendectomy with an average age of 37 years (range 6yrs-73yrs). They reported no deaths, no episodes of acute organ rejection, and no intraoperative complications after appendectomy. \r\n\r\nAcute rejection is the most frequent cause of death during the first year after OHT. Greater age at the time of transplantation increases the risk for acute rejection and is associated with lower survival. The risk of malignancy increases over time, with an incidence of approximately 10% at 10 years and 16% at 15 years post-transplant. Although post-transplant lymphoproliferative disorders account for the vast majority of malignancies and are associated with reduced survival, they are not one of the leading causes of mortality after OHT. \r\n\r\nThe patient\u2019s cardiac status appears to be optimized given compliance with medications, normal cardiac catheterization data and negative biopsy results. As immunosuppression can exacerbate acute appendicitis, prompt treatment is imperative with good outcomes having been reported after surgical management. Perioperative continuation of the anti-rejection therapy is important for recovery. Obtaining a preoperative echocardiogram would be helpful to confirm cardiac function but should not delay surgery. As six years have elapsed since OHT, this patient\u2019s risk for acute rejection and malignancy is lower than for CAV; thus, CAV would be the most likely cause of morbidity and mortality in this patient. \r\n\r\n\r\nREFERENCES \r\nDipchand AI, Laks JA. Pediatric heart transplantation: long-term outcomes. Indian J Thorac Cardiovasc Surg.<\/em>2020; 36(Suppl 2):175-189. \r\n\r\nRossano JW, Dipchand AI, Edwards LB, et al. The Registry of the International Society for Heart and Lung Transplantation: Nineteenth pediatric heart transplantation report-2016; Focus theme: Primary diagnostic indications for transplant. J Heart Lung Transplant. <\/em>2016; 35(10):1185-1195. \r\n\r\nDipchand AI. Current state of pediatric cardiac transplantation. Ann Cardiothorac Surg. <\/em>2018; 7(1):31-55. \r\n\r\nSavar A, Hiatt JR, Busuttil RW. Acute appendicitis after solid organ transplantation. Clin Transplant. <\/em>2006; 20(1):78-80.\r\n\r\n”,”hint”:””,”answers”:{“7b5nr”:{“id”:”7b5nr”,”image”:””,”imageId”:””,”title”:”A.\tAcute graft rejection”},”hrz7u”:{“id”:”hrz7u”,”image”:””,”imageId”:””,”title”:”B.\tCardiac allograft vasculopathy”,”isCorrect”:”1″},”jlc2f”:{“id”:”jlc2f”,”image”:””,”imageId”:””,”title”:”C.\tMalignancy”}}}}}}

{“questions”:{“nvky1”:{“id”:”nvky1″,”mediaType”:”image”,”answerType”:”text”,”imageCredit”:””,”image”:””,”imageId”:””,”video”:””,”imagePlaceholder”:””,”imagePlaceholderId”:””,”title”:”Authors: Christopher Busack MD, Chinwe Unegbu MD, and Daniela Perez-Velasco DO \u2013 Children\u2019s National Hospital \r\n\r\nA 6-month-old male with Hypoplastic Left Heart Syndrome (HLHS) s\/p Norwood\/Sano modification receives an ABO-incompatible heart transplant secondary to severe tricuspid regurgitation and right ventricular dysfunction. After separation from cardiopulmonary bypass, the patient received 10 mL\/kg each of platelets, cryoprecipitate, fresh frozen plasma, and packed red blood cells. Which of the administered blood products carries the HIGHEST RISK of transmitting viral pathogens?\r\n\r\n”,”desc”:”EXPLANATION \r\n\r\nTransfusion of blood products has significant risks and benefits which must be carefully balanced. A recent publication by Faraoni et al. provides evidence-based guidelines for the use of blood products in the perioperative period for children undergoing cardiac surgery. \r\nIn the US, to facilitate more targeted transfusion of deficient blood components, whole blood is typically separated into various components. Fresh frozen plasma (FFP) is frozen within 8 hours of collection. Cryoprecipitate, also known as antihemophilic factor, is then prepared from FFP in the following manner. FFP is slowly thawed to 1-6 ^{o <\/sup>C followed by centrifugation. High-molecular-weight plasma proteins form a precipitate during centrifugation known as cryoprecipitate, which is then is collected, resuspended in a small amount of plasma (10-15 mL) and refrozen. Cryoprecipitate has several important coagulation proteins including fibrinogen, antihemophilic factor (factor VIII), von Willebrand factor, fibrin stabilizing factor (factor XIII), fibronectin, and small amounts of other plasma proteins. Cryoprecipitate has higher concentrations of coagulation proteins due to the smaller volume; making this blood product more appropriate for smaller patients in need of an increased concentration of the aforementioned coagulation proteins. Cryoprecipitate doses of 1-2 units per 10 kg of body weight will increase fibrinogen concentration by 60 to 100 mg\/dL. \r\nIn the 1960\u2019s, cryoprecipitate was used to manage patients with Hemophilia A. The initial preparations of cryoprecipitate had relatively low Factor VIII concentrations. Therefore, Hemophilia A patients required transfusion of multiple bags of cryoprecipitate to achieve an adequate dose of 20-30 IU\/kg. Additionally, cryoprecipitate was pooled from large amounts of plasma obtained from multiple donors. Unfortunately, these specimens were often contaminated with hepatitis viruses. It is estimated that in the 1980\u2019s, HIV was transmitted to 50% of people living with Hemophilia A. In current medical practice, cryoprecipitate is used to correct fibrinogen deficiency due to acute blood loss (secondary to trauma, surgery, etc) or qualitative abnormalities of the fibrinogen protein. Currently, there are no widely available commercial methods of inactivating viral pathogens in FFP or cryoprecipitate. As cryoprecipitate is a pooled product, its administration carries the highest risk of the transmission of viral pathogens (Munlemvo et al). Many Western European countries and Canada have banned the use of cryoprecipitate due to concerns about pathogen transmission. Cryoprecipitate is no longer recommended to treat von Willebrand\u2019s Disease or Hemophilia A unless recombinant or viral inactivated products are not available. The availability of highly purified coagulation factor concentrates and recombinant protein preparations has superseded the use of cryoprecipitate for many coagulopathies. \r\nIn contrast, platelets are associated with the highest risk of bacterial contamination due to the need for storage at room temperature. Transfusion transmitted infections, although rare, can have serious consequences. Nucleic acid testing (NAT) has increased the sensitivity of detecting infectious agents in donor blood. This form of testing directly tests the donated blood for viruses, whereas previous screening was done by testing antibody response to viral infection. NAT has reduced the risk of infectious transmission to less than 1 in 1,000,000. Donor blood is now screened for many viruses and bacteria such as the following: HIV, hepatitis B, hepatitis C, HTLV, syphilis, West Nile virus, Chagas disease, Zika virus, and babesiosis. Leukoreduction of blood products is also used to decrease the risk of CMV transmission, which can be fatal in newborns and immunocompromised patients. \r\nTransfusion of blood products carries additional risks occurring with greater frequency than infectious transmission. Recent investigations suggest that blood product transfusion during pediatric cardiac surgery may be associated with adverse outcomes such as renal failure, low cardiac output, vascular thrombosis, and alloimmunization leading to increased time to orthotopic transplantation, prolonged hospital stay, and increased mortality. Guidelines have shifted away from recommending specific hemoglobin targets and instead weighing the risk of complications from blood product transfusion versus the risk of complications from inadequate oxygen-carrying capacity, inadequate hemostasis, and\/or inadequate intravascular volume. \r\nREFERENCES \r\n\r\n1. Faraoni D, Meier J, New HV, Van der Linden PJ, Hunt BJ. Patient Blood Management for Neonates and Children Undergoing Cardiac Surgery: 2019 NATA Guidelines. J Thorac Cardiovasc Anesth.<\/em> 2019; 33:3249-3263. https:\/\/doi.org\/10.1053\/j.jvca.2019.03.036 \r\n\r\n2. Munlemvo DM, Tobias JD, Chenault KM, Naguib A. Prothrombin Complex Concentrates to Treat Coagulation Disturbances: An Overview with a Focus on Use in Infants and Children. Cardiol Res.<\/em> 2022;13(1):18-26. doi:10.14740\/cr1342 \r\n\r\n3. Steinbicker AU, Wittenmeier E, Goobie SM. Pediatric non-red cell blood product transfusion practices: what\u2019s the evidence to guide transfusion of the \u201cyellow\u201d blood products? Curr Opin Anesthesiol. <\/em>2020;33(2):259-267. doi:10.1097\/ACO.0000000000000838 \r\n\r\n4. Busch MP, Bloch EM, Kleinman S. Prevention of transfusion-transmitted infections. Blood.<\/em> 2019;133(17):1854-1864. doi:10.1182\/blood-2018-11-833996 \r\n\r\n5. Sparrow RL, Simpson RJ, Greening DW. Preparation of Cryoprecipitate and Cryo-depleted Plasma for Proteomic Research Analysis. Methods Mol Biol.<\/em> 2023;2628:41-49. doi:10.1007\/978-1-0716-2978-9_\r\n”,”hint”:””,”answers”:{“68u32”:{“id”:”68u32″,”image”:””,”imageId”:””,”title”:”A. Platelets”},”p4irc”:{“id”:”p4irc”,”image”:””,”imageId”:””,”title”:”B. Cryoprecipitate”,”isCorrect”:”1″},”zah5m”:{“id”:”zah5m”,”image”:””,”imageId”:””,”title”:”C. Fresh Frozen Plasma (FFP)”},”5ajdc”:{“id”:”5ajdc”,”image”:””,”imageId”:””,”title”:”D. Packed Red Blood Cells (PRBC)”}}}}}}