570064 research-article2015

SCVXXX10.1177/1089253215570064Seminars in Cardiothoracic and Vascular AnesthesiaIng and Twite

The Perioperative Year in Review 2014

The Year in Review: Anesthesia for Congenital Heart Disease 2014

Seminars in Cardiothoracic and Vascular Anesthesia 2015, Vol. 19(1) 12­–20 © The Author(s) 2015 Reprints and permissions: sagepub.com/journalsPermissions.nav DOI: 10.1177/1089253215570064 scv.sagepub.com

Richard J. Ing, MBBCh, FCA (SA)1,2, and Mark D. Twite, MB, BChir, FRCP1,2

Abstract Congenital cardiac anesthesiology is a rapidly expanding field at both ends of the life spectrum. The care of the unborn child with congenital heart disease is becoming highly specialized in regional centers that offer advanced imaging techniques, coordinated specialist care, and potentially fetal interventions. As more children with congenital heart disease survive to adulthood, patients and their health care providers are facing new challenges. The growing volume of publications reflects this expanding field of congenital cardiac anesthesiology. This year in review article highlights some developing trends in the literature. Keywords congenital heart disease, anesthesia, cardiac surgery, cardiopulmonary bypass

Introduction The aim of this review is to present articles published in the past 18 months that may be of particular interest to the cardiac anesthesiologist caring for children and adults with congenital heart disease (CHD). Similar to our last year in review for 2013, the same terms were used to search the US National Library of Medicine PubMed database: congenital heart disease, anesthesia, cardiac surgery, and cardiopulmonary bypass.1 Articles published from July 2013 to December 2014 were evaluated broadly for their relevance, interest factor, and potential impact both now and in the future for the specialty of cardiac surgery and anesthesia. Nine themes emerged from the selected articles: (a) cardiomyocyte research, (b) cardiac imaging in young children, (c) cardiopulmonary bypass and organ protection, (d) monitoring the brain, (e) the airway, (g) singleventricle physiology, (h) noninvasive monitoring and medications, (i) arrhythmias, and (j) current outcomes and expectations for patients with CHD.

Cardiomyocyte Research The human heart is believed to grow by hypertrophy rather than proliferation of cardiomyocytes. However, recent studies have shown that cardiomyocyte proliferation is a mechanism of cardiac growth and regeneration in animals. In mice, a preadolescence proliferative burst of binuclear cardiomyocytes is triggered predominantly by thyroid hormone.2 In humans, it has been shown that cardiomyocyte proliferation contributes to heart development and growth until age 20 years. This suggests that

children and adolescents may be able to regenerate myocardium, that abnormal cardiomyocyte proliferation may be involved in certain myocardial diseases, and that these may be treatable through manipulation of cardiomyocyte proliferative pathways.3 Cardiac surgery in infants and children may result in myocardial fibrosis, arrhythmias, and myocardial dysfunction later in life. To prevent these problems from developing, novel intracoronary infusions of stem cells following cardiac surgery in children are being undertaken in Phase I and II controlled trials in an effort to improve myocardial function in failing single ventricle patients. Initial results injecting cardiospherederived cells (CDCs) into coronary arteries in the catheterization laboratory are very encouraging.4 Benefits may be greater in the young, as infants have been shown to have stronger regenerative CDCs compared with adults.5 Adults have not been left out of this research. Ischemic heart disease is a major public health problem around the world. A large loss of cardiomyocytes through apoptosis and necrosis underlies myocardial infarction. To compensate for the death of cardiomyocytes in the injured area, scar tissue is formed by fibroblasts. Reprogramming myocardial fibroblasts into functional cardiomyocyte cells with an exogenously administered micro-RNA and 1

Children’s Hospital Colorado, Anschutz Medical Campus, Aurora, CO, USA 2 University of Colorado School of Medicine, Aurora, CO, USA Corresponding Author: Mark Twite, Department of Anesthesiology, B090, Children’s Hospital Colorado, 13123 E 16th Ave, Aurora, CO 80045, USA. Email: [email protected]

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Ing and Twite transcription factor cocktail may significantly change the prognosis for patients with damaged myocardium regardless of the cause.6,7 Much of this research is being extended into reparative strategies for the liver, spinal cord, pancreas, and brain. However, the safety of viral vectors to deliver cell-reprogramming factors that have the ability to alter DNA is still a concern.

Cardiac Imaging in the Very Young The frontier of fetal cardiac medicine has evolved over the past 20 years largely due to improved imaging modalities, including 3- and 4-dimensional echocardiography, magnetic resonance imaging, and magnetocardiography, which are all now commonplace in clinical practice. The field of fetal medicine has advanced to a point of accurate and earlier diagnosis of fetal cardiac anomalies with planning and timely referrals to cardiac centers rapidly becoming the standard of care. Within the specialty a wide selection of cardiac fetal interventions are now available to infants and their families at maternal–fetal centers of excellence. A comprehensive document on the diagnosis and treatment of fetal cardiac disease has recently been published. It is endorsed by the American Heart Association and delineates the intricacies in the field of fetal cardiac medicine very clearly.8 The request for an imaging study in radiology or the cardiac catheterization laboratory in a critically ill infant with heart disease usually gathers the full attention of the cardiac anesthesiologist. One often hears questions like “Is this test really necessary and will it make a difference to management or diagnosis?” Until recently we believed these tests did help, but we had no data. A recent study on the yield of cardiac magnetic resonance imaging (cMRI) as an adjunct to echocardiography in young infants with CHD has found that cMRI delineated additional important anatomical information in 76% of patients, and in more than 50% of these infants, significant new findings affected surgical decision-making. The study authors advocate developing preoperative criteria for this testing modality, to help define cost-effectiveness in this patient population.9 The trend of utilizing more computed tomography (CT) cardiac angiograms has been shown to be associated with a decrease in cardiac catheterizations.10 Many of these scans are successfully being acquired as nonsedated, free breathing cardiac CT evaluations in patients with complex CHD.10,11 However, the cumulative doses of radiation from the cardiac catheterization laboratory, repeat chest X-rays, and CT imaging is a cause for concern in children with CHD. It has been shown that a significant cumulative exposure to ionizing radiation is received over the lifetime of many such patients. Overall, the median cumulative effective dose was 2.7 mSv (range = 0.1-76.9 mSv), and the associated lifetime attributable risk of cancer was 0.07% (range = 0.001% to 6.5%).12

Cardiopulmonary Bypass and Organ Protection Perioperative organ protection of the brain and other vital organ systems are some of the primary goals during cardiopulmonary bypass (CPB) for children and adults undergoing heart surgery. Despite the widespread adoption of near-infrared spectroscopy (NIRS) as a standard monitoring system for hemodynamic changes and cerebral perfusion trends in children undergoing cardiac surgery on CPB, very little data exist showing improved outcomes with its use. However, Abu-Sultaneh et al in a very thought-provoking small study add credence to the value of cerebral NIRS monitoring.13 Utilizing cerebral NIRS and measuring S100B in a prospective study, they showed that patients greater than 4 kg who are placed on CPB and had a cerebral arteriovenous oxygen difference greater than 50 (indicating a high cerebral oxygen extraction ratio) had a significantly higher peak serum S100B post-CPB. S100B is a novel brain injury protein biomarker derived from glial cells. It has a short half-life of 60 to 90 minutes. The authors advocate further studies and maintenance of a regional cerebral oxygenation value greater than 50% measured by NIRS in the peri-CPB period to try and avoid prolonged periods of cerebral desaturation and cerebral injury as measured by raised S100B.13 At the other end of the spectrum, hyperoxia on initiation of CPB is also known to be deleterious to patients. Caputo et al in an elegant study showed strong evidence that nitrogen, introduced at a rate of 100 to 200 mL/min into the oxygenator via a 0.2 µm bacteriologic filter, can control the CPB circuit delivered PaO2 to match the patient’s own preoperative PaO2 and avoid a significant hyperoxic injury. This approach results in decreased markers of inflammation, organ damage, and oxidative stress, especially in cyanotic single-ventricle pediatric patients undergoing heart surgery.14 Other strategies of organ protection during CPB may include remote ischemic preconditioning (RIPC). Interestingly, in the first randomized controlled trial of RIPC in a heterogeneous group of children undergoing CPB surgery, RIPC was shown to be beneficial to the heart.15 However, 2 recent articles refute the benefits of RIPC in children. One article is by the same authors. Both studies failed to find any protective effects of RIPC on the heart, kidneys, or brain in a homogenous group of 39 hypoxic neonates and a heterogeneous group of 299 children undergoing cardiac surgery on CPB.16,17 Currently, therefore, RIPC has not been proven to confer any significant clinical benefit in children undergoing heart surgery with CPB. Continuing the theme of CPB-related organ protection, intestinal integrity may be disrupted by ischemic-reperfusion injury following CPB. An interesting study utilizing novel gastrointestinal biomarkers, plasma intestinal fatty acid-binding protein, citrulline, claudin 3, and plasma inflammatory markers in 20 children undergoing

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heart surgery with CPB showed that these children have preoperative evidence of a loss of intestinal integrity. Additionally, greater severity of illness requiring increased cardiopulmonary support, rather than CPB-induced inflammation, may be responsible for postoperative intestinal epithelial barrier dysfunction.18

Monitoring the Brain Despite the absence of evidence that monitoring improves outcomes, we do know the importance of organ protection and we now have a deeper understanding of cerebral autoregulation in children on CPB.19 Therefore, it is not surprising that there are many strong recommendations to consider ways to monitor organ protection noninvasively, with multimodal neurological monitoring regarded as essential in pediatric cardiac anesthesia.20,21 A recent study using MRI and optics in 32 neonates with CHD prior to cardiac surgery quantified their cerebral oxygenation. The main finding was one of striking low cerebral blood flow and cerebral metabolism. The authors conclude that the brains of term infants with severe CHD are similar to the brains of premature infants.22 There are some excellent reviews of the topic of multimodal neurological monitoring and NIRS.20,23 We know that male sex, aortic atresia, and lower total brain maturation score are associated with greater neonatal white matter injury in patients with hypoplastic left heart syndrome (HLHS) undergoing cardiac surgery.24 Protecting the brain is important as adverse neurological outcomes are observed in up to 50% of infants following complex cardiac surgery.25 The association of brain injury and volatile anesthetic agent exposure was recently determined in a study of 59 patients followed over a 12-month period after cardiac surgery.25 As a result of these findings, neurodevelopmental follow-up after cardiac surgery is strongly recommended by many cardiac centers.26,27 Monitoring the brain when children are placed on venoarterial extracorporeal membrane oxygenation is also essential. A recent study in 2977 patients from the Extracorporeal Life Support Organization registry during 2007-2008 has shown that the majority of patients were cannulated via the carotid artery (66%) and that these patients had the highest burden of neurologic injury (22%).28 Recommendations are not necessarily to avoid the carotid arteries for ECMO cannulation but to be aware of the associated morbidity and to monitor the brain for neurologic injury.

this, over the past decade many centers have moved away from a postcardiac surgery trend of slow ventilation and inotrope wean to an early extubation (EE) strategy. The reported success rate of EE in the operating room following pediatric heart surgery over the past 24 years has been consistently high, ranging from 71% to 87%, with greater success being achieved in children older than 3 months of age. The reported re-intubation rate over the same time period is 6% to 10%, with most studies consistently showing less complications in the EE, less inotrope requirements, and shorter length of intensive care unit stay.29-32 This year, 3 articles confirm the safety and efficacy of goal-directed EE in neonatal and older pediatric cardiac surgical patients. This trend of successful EE continues to become synonymous with the multidisciplinary care team model of the perioperative cardiac patient.29-32 Anesthesiologists play an important role in this regard with evidence that judicious intraoperative opiate administration and the utilization of regional analgesia in carefully selected patients improves EE rates.31

Congenital Tracheal Stenosis in Association With Congenital Heart Defects Congenital tracheal stenosis involving greater than 50% of tracheal length is a severe and life-threatening anatomical lesion that has successfully been treated by surgical slide tracheoplasty (STP) since 1989, with mortality rates reported between 5% and 30%.33-35 A recent single-center 17-year experience in 101 patients has shown that preoperative bronchomalacia, particularly of the distal bronchi, is a significant risk factor for perioperative death. Additionally, post-STP repair, bronchomalacia may become more apparent due to elimination of the stenosis and relief of distal airway air trapping. Following STP these children require regular preemptive bronchoscopy and gentle balloon dilation usually for about 1 year to control granulation tissue and airway narrowing.33 Another study reports 43 patients with both cardiac lesions and tracheal stenosis lesions undergoing 1-stage surgical correction at a single center.36 The commonest cause of death in this study was late regrowth of granulation tissue in the airway, a similar problem described in the former study.

Single-Ventricle Physiology Stage 1 Palliation

The Airway Early Extubation Following Cardiac Surgery in Children Institutional differences account for variability in extubation times following cardiac surgery in children. Despite

The early postoperative recovery period of neonates with HLHS palliated with the Norwood procedure is frequently associated with hemodynamic instability, low oxygen transport, anaerobic metabolism, and lactic acidosis. A recent study challenges the notion that clinical hemodynamic parameters are enough to accurately reflect the

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Ing and Twite delivery of oxygen (DO2) in neonates following the Norwood procedure. The authors produce compelling data in this study population that a higher heart rate and systolic arterial blood pressure (SAP) do not reflect a higher cardiac output (CO). Rather, when SAP and heart rate are high, a correlation with increased VO2, not DO2, is found.37,38 An additional study that lends support to this observation compares DO2 kinetics to those predicted by mathematical modeling in 52 HLHS patients in the cardiac catheterization laboratory just prior to stage 2 palliation. The data shows that DO2 in this group of patients is best correlated (r2 = .8755) with arterial oxygen saturation (SaO2) only when the formula SaO2/(SaO2 − SvO2) is applied, where SvO2 is the mixed venous oxygen saturation.39 The authors point out that only measuring SvO2 in this patient population is not enough because a low value, indicative of a high oxygen extraction ratio, does not determine if it is due to globally low DO2 or a higher VO2.37 Infants with HLHS who have been palliated with the Norwood procedure are known to have poor weight gain both in the hospital postoperatively and during the first interstage surgical period prior to stage 2 palliation. This failure to gain weight has been shown to occur despite supplementation with total parenteral nutrition (TPN) while in intensive care.40 The institution of parental home surveillance programs following the Norwood operation has been shown to significantly decrease the interstage mortality from 7% to 10% to almost 0%.41,42 Parents maintain daily logs on their children, looking for concerning changes including pulse oximetry saturation less than 70%, an acute weight loss of more than 30 g in 24 hours, or failure to gain at least 20 g in a 3-day period. This approach helps identify at-risk children triggering a consultation with their cardiologist and potentially leading to an earlier visit to the cardiac catheterization laboratory for diagnosis and possible intervention. It has also resulted in earlier transition to stage 2 palliation with excellent outcomes and no increase in morbidity or mortality.41,42 These successful programs are developing at most centers caring for high-risk single-ventricle infants and are rapidly becoming the standard of care.

Stage 2 Palliation Since publication of the single-ventricle reconstruction trial of HLHS patients palliated with the modified BlalockTaussig shunt (MBTS) compared with the right ventricleto-pulmonary artery shunt (RVPAS), we have awaited the results of the same cohort of patients following the stage 2 superior cavopulmonary anastomosis operation.43 Concerns raised at the time of the trial were that the shunt type might determine outcomes. In this same cohort of patients at 15 centers who have undergone the second

stage procedure during 2005 to 2008, some of the answers to that question are now available.44 The authors found that pulmonary artery stenosis was an independent risk factor related to the length of stay (LOS) during the Norwood procedure but the shunt type at the first stage procedure was not an independent risk factor for LOS during stage 2 palliation. Mortality risk factors during stage 2 palliation were a nonelective stage 2 procedure, atrioventricular valve (AVV) regurgitation, and the need for AVV repair.44

Stage 3 Palliation An update on outcomes following the Fontan operation in New Zealand and Australia probably reflects practice in many other parts of the world.45 The study authors report that patients with HLHS now account for up to 17% of all Fontan procedures, and after 2006 the external cardiac conduit (ECC) was exclusively performed. The overall operative mortality rate for patients with HLHS undergoing the Fontan procedure remains low at 1%.45 As in other studies, the group of HLHS Fontan patients had more pleural effusions, and on average stayed 2 days longer in hospital.45 Interestingly, a recent multicenter study has found no advantage of the ECC over the intracardiac Fontan in terms of arrhythmias incidence following the Fontan procedure.46 The authors of this study recommend considering other factors to determine which type of conduit to place, rather than the focus on minimizing arrhythmias by a certain surgical technique in these single-ventricle patients.46 Follow-up studies on Fontan patients continue to expand our knowledge on long-term outcomes. One study of 546 Fontan survivors aged 11.9 ±3.4 years, who were assessed 6.8 ±0.4 years after their Fontan surgery, found a 95% interim transplant-free survival.47 Radman and colleagues showed that a preoperative B-type natriuretic peptide (BNP) level of 40 pg/mL or greater was highly associated with early postoperative extracorporeal life support (ECLS), prolonged LOS, and the need for early take down (within 12 months) of the Fontan palliation. The authors suggest that preoperative BNP levels, after validation in a larger cohort study, should be considered as an adjunct assessment of Fontan surgical candidates.48 Despite the widespread use of afterload reducing medications, aimed at reducing atrial and ventricular end-diastolic pressures, in the cardiac intensive care unit following the Fontan procedure, a recent prospective randomized trial has found no benefit to this practice. In their study, Costello and colleagues showed that milrinone administration was discontinued in 25% of subjects who received it because of hypotension. Additionally, arrhythmias were twice as common in patients receiving milrinone. The authors conclude that milrinone should not be used following the Fontan operation.49 Interestingly, another study has

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found that the incidence of vasoplegia in adult patients with right-sided congenital heart defects undergoing cardiac surgery was twice as high as those patients undergoing left-sided aortic surgery. Vasopressin levels were measured but were not found to be associated with vasoplegia in the right-sided heart defect group.50 This information might be important for the cardiac anesthesiologist to consider as they administer post-CPB inotrope and vasodilator infusions. Examining adolescents older than 15 years of age who had undergone a first Fontan procedure later in life, Valente and colleagues have shown a 51% survival 20 years following repair in their cohort of 82 patients. The authors mention the difficulty of patient follow-up for ongoing care in this patient group.51 When the Fontan operation fails in any given patient, it may be manifest by ventricular dysfunction, renal failure, protein losing enteropathy, plastic bronchitis, or intractable arrhythmias. In this situation, despite the high surgical risk, a heart transplant may be the only alternative for some of these patients. This remains a particular high-risk group of patients. A recent single-center experience with these types of procedures has found a 23% early mortality due to graft failure, pulmonary hypertension, and infection.52

advises the use of a balanced anesthetic technique as no one medication is able to provide hemodynamic stability in these patients.55 Some established drugs are finding new applications in pulmonary hypertension. In a piglet model of pulmonary vein stenosis, Losartan has been found to improve pulmonary vein stenosis associated pulmonary hypertension and its use was associated with diminished pulmonary vein intimal hyperplasia. The authors conclude that Losartan could be a useful adjunct following surgical repair of pulmonary vein stenosis.56 This is an interesting study because recurrent pulmonary vein stenosis following surgical repair is associated with increased risk of recurrence, reoperation, and death with a reported incidence of 30% to 45%.57 A recent catheterization laboratory study on the systemic effects of intracoronary nitroglycerin administration during 41 coronary angiographies in 25 heart transplant recipient children studied retrospectively over a 5-year period has shown hemodynamic safety with no significant changes to systolic blood pressure or heart rate.58 A study in a small group of patients has recently shown that propofol, despite lowering cardiac output, leads to a modest but significant increase in cerebral tissue oxygenation as measured by NIRS. The authors postulate the mechanism to be decreased oxygen consumption in the sedated brain with an intact cerebral autoregulation reflex.59

Noninvasive Monitoring and Medications

Arrhythmias

As important as SvO2 is as a marker of global oxygen delivery, in a prospective observational study in 26 patients, older than 18 years of age with severe critical illness and heart failure, Romagnoli and colleagues caution on the utilization of central venous oxygen saturation (ScvO2) in isolation as a surrogate marker of true mixed venous oxygen (SvO2). The authors advocate that ScvO2 should not be considered a substitute of SvO2 in all instances; however, when a value less than 70% is detected, it represents a reliable early warning sign of potential impending cardiorespiratory compromise.53 One of the cornerstones of maintaining adequate DO2 under anesthesia in children is ensuring adequate cardiac output (CO). Until recently, noninvasive monitoring in this population was not easy to use. A recent observational study in 374 pediatric patients utilizing a continuous noninvasive thoracic electrical bioimpedence monitor with 4 electrocardiogram (EKG) electrodes was shown to provide real-time hemodynamic information that successfully tracked responses to interventions under anesthesia in children. The study authors believe this type of technology has a future in anesthesia monitoring.54 A review of anesthetic drugs in CHD is a timely reminder of the effects of anesthetic drugs on patients with severe pulmonary hypertension and myocardial dysfunction. Friesen delineates the effects of medications commonly used and

A high incidence of arrhythmias remains a major contributor to morbidity and mortality in children with CHD and in those patients with an underlying myocardial substrate susceptible to medication-induced arrhythmias. Tachyarrhythmias occur in at least 34% to 50% of patients following the Norwood procedure. The majority are supraventricular in nature, and more than 60% of these patients are frequently discharged home on antiarrhythmic medications.60,61 Patients who have persistent, hemodynamically compromising tachyarrhythmia may require mechanical support. If mechanical support is instituted early enough, survival for these patients is close to 60%, with 30% of patients requiring radiofrequency arrhythmia ablation while on mechanical support.62 Cardiac channelopathies are of interest to the cardiac anesthesiologist. They are a group of myocardial diseases that predispose susceptible patients to sudden unexplained death and drug-induced prolongation of cardiac repolarization and malignant ventricular arrhythmias.63-65 A recent forensic study has found that at least 13% to 20% of sudden unexplained cardiac death in children and adults may be related to cardiac channelopathies.65 Although there are numerous reports on the safety of modern anesthetics for patients with cardiac channelopathies, adequate preoperative preparation with beta-blockers and a premedication is regularly utilized by those providing anesthesia for these patients.64

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Ing and Twite

Current Outcomes and Expectations for Patients With Congenital Heart Disease CHD is the most common congenital disorder of newborns, affecting 1% of live births. With the significant advances in cardiovascular medicine and surgery over the past decades, 85% of affected children will now survive to adulthood. Patients with CHD may be repaired, palliated, or left unrepaired but almost all patients will have life-long sequelae.66,67 Marelli and colleagues, utilizing large universal health care databases in Quebec, Canada, have studied the changing epidemiology of CHD.68 In their publication this year, they have shown the dramatic increase in the number of adults living with CHD over the past decade while the number of affected children has remained level. Furthermore, the median age of patients with severe CHD has increased over the years from age 11 years in 1985 to age 25 years in 2010. The main reason for this shifting epidemiology is the decrease in mortality at all ages in patients with CHD.69 The largest reduction in mortality is in infants and is probably due to prenatal diagnosis of CHD, which has enabled coordinated care in specialized centers. In addition to the organization of specialized teams and units to care for patients with severe CHD, novel surgical and interventional techniques continue to evolve. As more adults with CHD live longer, the predicted future mortality will increase over time as shown by a recent single center study in Toronto, Canada.70 It is estimated that there are 1.5 million adults living with CHD in the United States. However, only about 20% are seen in centers that specialize in adult congenital heart disease (ACHD). The remainder either receives no followup care or is seen by general adult cardiologists or pediatric cardiologists. There are only around 200 cardiologists with a special interest and training in ACHD in the United States. This lack of available providers and specialized centers is a serious problem in the delivery of care to ACHD patients.71-73 There are clear consensus guidelines in the United States, Canada, and Europe for developing ACHD centers.74-76 The most important aspect of these specialized centers is the multidisciplinary approach of providers to address not only the cardiac needs of the patients but also any comorbidities common in adulthood. Access to different imaging techniques is also essential, including echocardiography and cMRI. In their 2014 publication, Mylotte and colleagues showed that several years after the introduction of ACHD center guidelines in Canada there was a 7.4% increase in patients referred to specialized centers, and 2 years after this increased referral pattern the number of deaths in patients with ACHD decreased by 5%.77 The leading indications for admission to hospital in ACHD patients are heart failure, arrhythmias, and

coronary artery disease.78 The probability of heart failure increases with both age and complexity of the CHD.79 Adults with single-ventricle physiology who have been palliated to a Fontan circulation are at high risk, as the single ventricle has to overcome the resistance of both the systemic and pulmonary circulations in series. Adults who have had tetralogy of Fallot repaired in childhood, and probable further interventions into adulthood, have an increased probability of developing heart failure because pulmonary regurgitation causes right ventricular dilation and dysfunction, which will eventually lead to an abnormal septal configuration and altered right ventricle and left ventricle interactions and eventually left ventricular dysfunction and biventricular heart failure. Another high-risk congenital heart lesion is transposition of the great arteries (TGA) that has been palliated with a Mustard or Senning procedure. This procedure leaves the right ventricle as the systemic ventricle that has an increased probability of developing heart failure. The arterial switch procedure pioneered by Adib Jatene in the 1970s has almost completely replaced the Senning/Mustard approach to TGA and decreased heart failure in this subgroup.80 Superimposed on the myocardial reasons for developing heart failure are the age-related changes of coronary disease. It is essential that adults with CHD understand the importance of preventative measures such as diet and exercise to reduce their risk of developing heart failure. However, these lifestyle changes may be difficult for many patients with severe CHD.67 There are many factors that may contribute to the development of arrhythmias in ACHD. These include anomalies of the conductions systems and changes to it caused by surgery. Coronary artery disease is an additional risk factor, as patients get older. Often it is difficult to interpret the EKG in these patients due to the structural abnormalities of the heart and other imaging modalities such as cMRI are often helpful.81 The risk estimate for developing arrhythmias in CHD is related to the complexity of the underlying lesion. The more severe the CHD is, the greater the likelihood that arrhythmias will develop at some point during the patient’s lifetime. One notable exception to this is Ebstein’s anomaly, which is much more likely to lead to atrial arrhythmias. There is a clear relationship between cardiac dysynchrony and the exacerbation of heart failure, so therapy for both problems is often required. The expert consensus statement on the recognition and management of arrhythmias is an excellent resource published this year.82

Conclusion The survival of patients with CHD is a remarkable success story of modern medicine. The large number of excellent publications in this field demonstrates that there is still a

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lot to learn and that many people are committed to improving the lives of patients with CHD. There are a growing number of adults who now live with complex CHD, and it is essential that services are developed to provide coordinated care for them. Cardiac anesthesiologists are uniquely positioned due to their training in cardiac anesthesia to lead the way in providing anesthesia services for patients with CHD from “cradle to grave.” Rather than divide ourselves into pediatric and adult cardiac anesthesiologists, we may need to train the next generation of “congenital cardiac anesthesiologists.” As many complex CHD patients survive into adulthood new challenges will be faced, and a congenital cardiac anesthesiologist will be able to provide the perioperative care home that these patients require. Declaration of Conflicting Interests The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding The author(s) received no financial support for the research, authorship, and/or publication of this article.

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10. Han BK, Overman DM, Grant K, et al. Non-sedated, free breathing cardiac CT for evaluation of complex congenital heart disease in neonates. J Cardiovasc Comput Tomogr. 2013;7:354-360. 11. Han BK, Vezmar M, Lesser JR, et al. Selective use of cardiac computed tomography angiography: an alternative diagnostic modality before second-stage single ventricle palliation. J Thorac Cardiovasc Surg. 2014;148:1548-1554. 12. Johnson JN, Hornik CP, Li JS, et al. Cumulative radiation exposure and cancer risk estimation in children with heart disease. Circulation. 2014;130:161-167. 13. Abu-Sultaneh S, Hehir DA, Murkowski K, et al. Changes in cerebral oxygen saturation correlate with S100B in infants undergoing cardiac surgery with cardiopulmonary bypass. Pediatr Crit Care Med. 2014;15:219-228. 14. Caputo M, Mokhtari A, Miceli A, et al. Controlled reoxygenation during cardiopulmonary bypass decreases markers of organ damage, inflammation, and oxidative stress in single-ventricle patients undergoing pediatric heart surgery. J Thorac Cardiovasc Surg. 2014;148:792-801.e8. 15. Cheung MM, Kharbanda RK, Konstantinov IE, et al. Randomized controlled trial of the effects of remote ischemic preconditioning on children undergoing cardiac surgery: first clinical application in humans. J Am Coll Cardiol. 2006;47:2277-2282. 16. Jones BO, Pepe S, Sheeran FL, et al. Remote ischemic preconditioning in cyanosed neonates undergoing cardiopulmonary bypass: a randomized controlled trial. J Thorac Cardiovasc Surg. 2013;146:1334-1340. 17. McCrindle BW, Clarizia NA, Khaikin S, et al. Remote ischemic preconditioning in children undergoing cardiac surgery with cardiopulmonary bypass: a single-center double-blinded randomized trial. J Am Heart Assoc. 2014;3(4). doi:10.1161/JAHA.114.000964. 18. Typpo KV, Larmonier CB, Deschenes J, Redford D, Kiela PR, Ghishan FK. Clinical characteristics associated with postoperative intestinal epithelial barrier dysfunction in children with congenital heart disease. Pediatr Crit Care Med. 2014;16:37-44. 19. Brady KM, Mytar JO, Lee JK, et al. Monitoring cerebral blood flow pressure autoregulation in pediatric patients during cardiac surgery. Stroke. 2010;41:1957-1962. 20. Andropoulos DB, Stayer SA, Diaz LK, Ramamoorthy C. Neurological monitoring for congenital heart surgery. Anesth Analg. 2004;99:1365-1375. 21. Mittnacht AJ, Rodriguez-Diaz C. Multimodal neuromonitoring in pediatric cardiac anesthesia. Ann Card Anaesth. 2014;17:25-32. 22. Jain V, Buckley EM, Licht DJ, et al. Cerebral oxygen metabolism in neonates with congenital heart disease quantified by MRI and optics. J Cereb Blood Flow Metab. 2014;34: 380-388. 23. Scott JP, Hoffman GM. Near-infrared spectroscopy: exposing the dark (venous) side of the circulation. Paediatr Anaesth. 2014;24:74-88. 24. Goff DA, Shera DM, Tang S, et al. Risk factors for preoperative periventricular leukomalacia in term neonates with hypoplastic left heart syndrome are patient related. J Thorac Cardiovasc Surg. 2014;147:1312-1318.

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