2018 AHA/ACC Guideline for the Management of Adults With Congenital Heart Disease: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines

HomeCirculationVol. 139, No. 142018 AHA/ACC Guideline for the Management of Adults With Congenital Heart Disease: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines Free AccessReview ArticlePDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissionsDownload Articles + Supplements ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toSupplemental MaterialFree AccessReview ArticlePDF/EPUB2018 AHA/ACC Guideline for the Management of Adults With Congenital Heart Disease: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines Karen K. Stout, MD, FACC, Chair, Curt J. Daniels, MD, Vice Chair, Jamil A. Aboulhosn, MD, FACC, FSCAI, Biykem Bozkurt, MD, PhD, FACC, FAHA, Craig S. Broberg, MD, FACC, Jack M. Colman, MD, FACC, Stephen R. Crumb, DNP, AACC, Joseph A. Dearani, MD, FACC, Stephanie Fuller, MD, MS, FACC, Michelle Gurvitz, MD, FACC, Paul Khairy, MD, PhD, Michael J. Landzberg, MD, FACC, Arwa Saidi, MB, BCH, FACC, Anne Marie Valente, MD, FACC, FAHA, FASE and George F. Van Hare, MD, FACC Karen K. StoutKaren K. Stout Search for more papers by this author , Curt J. DanielsCurt J. Daniels Search for more papers by this author , Jamil A. AboulhosnJamil A. Aboulhosn Search for more papers by this author , Biykem BozkurtBiykem Bozkurt Search for more papers by this author , Craig S. BrobergCraig S. Broberg Search for more papers by this author , Jack M. ColmanJack M. Colman Search for more papers by this author , Stephen R. CrumbStephen R. Crumb Search for more papers by this author , Joseph A. DearaniJoseph A. Dearani Search for more papers by this author , Stephanie FullerStephanie Fuller Search for more papers by this author , Michelle GurvitzMichelle Gurvitz Search for more papers by this author , Paul KhairyPaul Khairy Search for more papers by this author , Michael J. LandzbergMichael J. Landzberg Search for more papers by this author , Arwa SaidiArwa Saidi Search for more papers by this author , Anne Marie ValenteAnne Marie Valente Search for more papers by this author and George F. Van HareGeorge F. Van Hare Search for more papers by this author Originally published16 Aug 2018https://doi.org/10.1161/CIR.0000000000000602Circulation. 2019;139:e637–e697is corrected byCorrection to: 2018 AHA/ACC Guideline for the Management of Adults With Congenital Heart Disease: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice GuidelinesOther version(s) of this articleYou are viewing the most recent version of this article. Previous versions: August 16, 2018: Ahead of Print Table of ContentsPreamble e6381. Introduction e6411.1. Methodology and Evidence Review e6411.2. Organization of the Writing Committee e6411.3. Document Review and Approval e6411.4. Scope of the Guideline e6421.5. Abbreviations e6422. Background and Pathophysiology e6432.1. Anatomic and Physiological Terms e6432.2. Severity of ACHD e6432.3. The ACHD Anatomic and Physiological Classification e6433. General Principles e6463.1. ACHD Program e6463.2. Access to Care e6483.3. Delivery of Care e6483.4. Evaluation of Suspected and Known CHD e6483.4.1. Electrocardiogram e6483.4.2. Ionizing Radiation Principles e6513.4.3. Echocardiography e6513.4.4. CMR Imaging e6513.4.5. Cardiac Computed Tomography e6513.4.6. Cardiac Catheterization e6513.4.7. Exercise Testing e6513.5. Transition Education e6513.6. Exercise and Sports e6523.7. Mental Health and Neurodevelopmental Issues e6523.8. Endocarditis Prevention e6523.9. Concomitant Syndromes e6523.10. Noncardiac Medical Issues e6533.11. Noncardiac Surgery e6533.12. Pregnancy, Reproduction, and Sexual Health e6533.12.1. Pregnancy e6533.12.2. Contraception e6543.13. Heart Failure and Transplant e6543.13.1. Heart Failure e6543.13.2. Heart Transplant e6543.14. Palliative Care e6543.15. Cyanosis e6543.16. Pharmacological Therapy for ACHD e6544. Specific Lesions e6554.1. Shunt Lesions e6554.1.1. Atrial Septal Defect e6554.1.2. Anomalous Pulmonary Venous Connections e6574.1.3. Ventricular Septal Defect e6574.1.4. Atrioventricular Septal Defect e6584.1.5. Patent Ductus Arteriosus e6594.2. Left-Sided Obstructive Lesions e6604.2.1. Cor Triatriatum e6604.2.2. Congenital Mitral Stenosis e6604.2.3. Subaortic Stenosis e6604.2.4. Congenital Valvular Aortic Stenosis e6614.2.4.1. Turner Syndrome e6614.2.5. Supravalvular Aortic Stenosis e6614.2.6. Coarctation of the Aorta e6624.3. Right-Sided Lesions e6634.3.1. Valvular Pulmonary Stenosis e6634.3.1.1. Isolated PR After Repair of PS e6644.3.2. Branch and Peripheral Pulmonary Stenosis e6654.3.3. Double-Chambered Right Ventricle e6654.3.4. Ebstein Anomaly e6664.3.5. Tetralogy of Fallot e6674.3.6. Right Ventricle to Pulmonary Artery Conduit e6694.4. Complex Lesions e6694.4.1. Transposition of the Great Arteries e6694.4.1.1. Transposition of the Great Arteries With Atrial Switch e6694.4.1.2. Transposition of the Great Arteries With Arterial Switch e6704.4.1.3. Congenitally Corrected Transposition of the Great Arteries e6714.4.2. Fontan Palliation of Single Ventricle Physiology (Including Tricuspid Atresia and Double Inlet Left Ventricle) e6724.4.3. Double Outlet Right Ventricle e6734.4.4. Severe PAH and Eisenmenger Syndrome e6734.4.4.1. Severe PAH e6734.4.4.2. Eisenmenger Syndrome e6744.4.5. Coronary Anomalies e6744.4.5.1. Anomalous Coronary Artery Evaluation e6744.4.5.2. Anomalous Aortic Origin of Coronary Artery e6764.4.5.3. Anomalous Coronary Artery Arising From the PA e6765. Evidence Gaps and Future Directions e676References e678Appendix 1 Author Relationships With Industry and Other Entities (Relevant) e693Appendix 2 Reviewer Relationships With Industry and Other Entities (Comprehensive) e695PreambleSince 1980, the American College of Cardiology (ACC) and American Heart Association (AHA) have translated scientific evidence into clinical practice guidelines (guidelines) with recommendations to improve cardiovascular health. These guidelines, which are based on systematic methods to evaluate and classify evidence, provide a cornerstone for quality cardiovascular care. The ACC and AHA sponsor the development and publication of guidelines without commercial support, and members of each organization volunteer their time to the writing and review efforts. Guidelines are official policy of the ACC and AHA.Intended UsePractice guidelines provide recommendations applicable to patients with or at risk of developing cardiovascular disease. The focus is on medical practice in the United States, but guidelines developed in collaboration with other organizations can have a global impact. Although guidelines may be used to inform regulatory or payer decisions, they are intended to improve patients’ quality of care and align with patients’ interests. Guidelines are intended to define practices meeting the needs of patients in most, but not all, circumstances and should not replace clinical judgment.Clinical ImplementationManagement in accordance with guideline recommendations is effective only when followed by both practitioners and patients. Adherence to recommendations can be enhanced by shared decision making between clinicians and patients, with patient engagement in selecting interventions on the basis of individual values, preferences, and associated conditions and comorbidities.Methodology and ModernizationThe ACC/AHA Task Force on Clinical Practice Guidelines (Task Force) continuously reviews, updates, and modifies guideline methodology on the basis of published standards from organizations, including the Institute of Medicine,P-1, P-2 and on the basis of internal reevaluation. Similarly, the presentation and delivery of guidelines are reevaluated and modified on the basis of evolving technologies and other factors to facilitate optimal dissemination of information to healthcare professionals at the point of care.Toward this goal, this guideline continues the introduction of an evolved format of presenting guideline recommendations and associated text called the “modular knowledge chunk format.” Each modular “chunk” includes a table of related recommendations, a brief synopsis, recommendation-specific supportive text, and when appropriate, flow diagrams or additional tables. References are provided at the end of the document in their respective sections. Additionally, this format will facilitate seamless updating of guidelines with focused updates as new evidence is published, as well as content tagging for rapid electronic retrieval of related recommendations on a topic of interest. This evolved approach format was instituted when this guideline was near completion; therefore, the present document represents a transitional format that best suits the text as written. Future guidelines will fully implement this format, including provisions for limiting the amount of text in a guideline.Recognizing the importance of cost–value considerations in certain guidelines, when appropriate and feasible, an analysis of the value of a drug, device, or intervention may be performed in accordance with the ACC/AHA methodology.P-3To ensure that guideline recommendations remain current, new data are reviewed on an ongoing basis, with full guideline revisions commissioned in approximately 6-year cycles. Publication of new, potentially practice-changing study results that are relevant to an existing or new drug, device, or management strategy will prompt evaluation by the Task Force, in consultation with the relevant guideline writing committee, to determine whether a focused update should be commissioned. For additional information and policies regarding guideline development, we encourage readers to consult the ACC/AHA guideline methodology manualP-4 and other methodology articles.P-5–P-8Selection of Writing Committee MembersThe Task Force strives to avoid bias by selecting experts from a broad array of backgrounds. Writing committee members represent different geographic regions, sexes, ethnicities, races, intellectual perspectives/biases, and scopes of clinical practice. The Task Force may also invite organizations and professional societies with related interests and expertise to participate as partners, collaborators, or endorsers.Relationships With Industry and Other EntitiesThe ACC and AHA have rigorous policies and methods to ensure that guidelines are developed without bias or improper influence. The complete relationships with industry and other entities (RWI) policy can be found online. Appendix 1 of the present document lists writing committee members’ relevant RWI. For the purposes of full transparency, writing committee members’ comprehensive disclosure information is available online. Comprehensive disclosure information for the Task Force is also available online.Evidence Review and Evidence Review CommitteesIn developing recommendations, the writing committee uses evidence-based methodologies that are based on all available data.P-4–P-7 Literature searches focus on randomized controlled trials but also include registries, nonrandomized comparative and descriptive studies, case series, cohort studies, systematic reviews, and expert opinion. Only key references are cited.An independent evidence review committee (ERC) is commissioned when there are 1 or more questions deemed of utmost clinical importance that merit formal systematic review. The systematic review will determine which patients are most likely to benefit from a drug, device, or treatment strategy and to what degree. Criteria for commissioning an ERC and formal systematic review include: a) the absence of a current authoritative systematic review, b) the feasibility of defining the benefit and risk in a time frame consistent with the writing of a guideline, c) the relevance to a substantial number of patients, and d) the likelihood that the findings can be translated into actionable recommendations. ERC members may include methodologists, epidemiologists, healthcare providers, and biostatisticians. The recommendations developed by the writing committee on the basis of the systematic review are marked with “SR.”Guideline-Directed Management and TherapyThe term guideline-directed management and therapy (GDMT) encompasses clinical evaluation, diagnostic testing, and pharmacological and procedural treatments. For these and all recommended drug treatment regimens, the reader should confirm the dosage by reviewing product insert material and evaluate the treatment regimen for contraindications and interactions. The recommendations are limited to drugs, devices, and treatments approved for clinical use in the United States.Class of Recommendation and Level of EvidenceThe Class of Recommendation (COR) indicates the strength of the recommendation, encompassing the estimated magnitude and certainty of benefit in proportion to risk. The Level of Evidence (LOE) rates the quality of scientific evidence that supports the intervention on the basis of the type, quantity, and consistency of data from clinical trials and other sources (Table 1).P-4–P-6Table 1. Applying Class of Recommendation and Level of Evidence to Clinical Strategies, Interventions, Treatments, or Diagnostic Testing in Patient Care* (Updated August 2015)Table 1. Applying Class of Recommendation and Level of Evidence to Clinical Strategies, Interventions, Treatments, or Diagnostic Testing in Patient Care* (Updated August 2015)The reader is encouraged to consult the full-text guidelineP-9 for additional guidance and details about adult congenital heart disease because this executive summary contains mainly the recommendations.Glenn N. Levine, MD, FACC, FAHAChair, ACC/AHA Task Force on Clinical Practice Guidelines1. Introduction1.1. Methodology and Evidence ReviewThe recommendations listed in this guideline are, whenever possible, evidence-based. An initial extensive evidence review, which included literature derived from research involving human subjects, published in English, and indexed in MEDLINE (through PubMed), EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline, was conducted from April 2014 to November 2014. Key search words included but were not limited to the following: adult congenital heart disease, anesthesia, aortic aneurysm, aortic stenosis, atrial septal defect, arterial switch operation, bradycardia, bicuspid aortic valve, cardiac catheterization, cardiac imaging, cardiovascular magnetic resonance, cardiac reoperation, cardiovascular surgery, chest x-ray, cirrhosis, coarctation of the aorta, congenital heart defects, congenitally corrected transposition of the great arteries, contraception, coronary artery abnormalities, cyanotic congenital heart disease, dextro-transposition of the great arteries, double inlet left ventricle, Ebstein anomaly, echocardiography, Eisenmenger syndrome, electrocardiogram, endocarditis, exercise test, Fontan, heart catheterization, heart defect, heart failure, infertility, l-transposition of the great arteries, medical therapy, myocardial infarction, noncardiac surgery, patent ductus arteriosus, perioperative care, physical activity, postoperative complications, pregnancy, preoperative assessment, psychosocial, pulmonary arterial hypertension, hypoplastic left heart syndrome, pulmonary regurgitation, pulmonary stenosis, pulmonary valve replacement, right heart obstruction, right ventricle to pulmonary artery conduit, single ventricle, supravalvular pulmonary stenosis, surgical therapy, tachyarrhythmia, tachycardia, tetralogy of Fallot, transplantation, tricuspid atresia, Turner syndrome, and ventricular septal defect. Additional relevant studies published through January 2018, during the guideline writing process, were also considered by the writing committee, and added to the evidence tables when appropriate. The final evidence tables, included in the Online Data Supplement, summarize the evidence used by the writing committee to formulate recommendations. References selected and published in this document are representative and not all-inclusive.As noted in the preamble, an independent ERC was commissioned to perform a formal systematic review of critical clinical questions related to adult congenital heart disease (ACHD), the results of which were considered by the writing committee for incorporation into this guideline. Concurrent with this process, writing committee members evaluated study data relevant to the rest of the guideline. The findings of the ERC and the writing committee members were formally presented and discussed, and then recommendations were developed. The systematic review reports on “Medical Therapy for Systemic Right Ventricles: A Systematic Review (Part 1) for the 2018 AHA/ACC Guideline for the Management of Adults With Congenital Heart Disease”S1.1-1 and “Interventional Therapy Versus Medical Therapy for Secundum Atrial Septal Defect: A Systematic Review (Part 2) for the 2018 AHA/ACC Guideline for the Management of Adults With Congenital Heart Disease”S1.1-2 are published in conjunction with this guideline.1.2. Organization of the Writing CommitteeThe writing committee consisted of pediatric and adult congenital cardiologists, interventional cardiologists, electrophysiologists, surgeons, and an advance practice nurse. The writing committee included representatives from the ACC, AHA, and American Association for Thoracic Surgery (AATS), American Society of Echocardiography (ASE), Heart Rhythm Society (HRS), International Society for Adult Congenital Heart Disease (ISACHD), Society for Cardiovascular Angiography and Interventions (SCAI), and the Society of Thoracic Surgeons (STS).1.3. Document Review and ApprovalThis document was reviewed by 3 official reviewers each nominated by the ACC and AHA, and 1 to 2 reviewers each from the AATS, ASE, HRS, ISACHD, SCAI, STS; and 32 individual content reviewers. Reviewers' RWI information was distributed to the writing committee and is published in this document (Appendix 2).This document was approved for publication by the governing bodies of the ACC and the AHA and endorsed by the AATS, ASE, HRS, ISACHD, SCAI, and STS.1.4. Scope of the GuidelineThe 2018 ACHD guideline is a full revision of the “2008 ACC/AHA Guidelines for the Management of Adults with Congenital Heart Disease,”S1.4-1 which was the first US guideline to be published on the topic. This revision uses the 2008 ACHD guideline as a framework and incorporates new data and growing ACHD expertise to develop recommendations. Congenital heart disease (CHD) encompasses a range of structural cardiac abnormalities present before birth attributable to abnormal fetal cardiac development but does not include inherited disorders that may have cardiac manifestations such as Marfan syndrome or hypertrophic cardiomyopathy. Also not included are anatomic variants such as patent foramen ovale. Valvular heart disease (VHD) may be congenital, so management overlaps with the “2014 AHA/ACC Guidelines for the Management of Patients With Valvular Heart Disease,”S1.4-2 particularly for bicuspid aortic valve (BAV) disease. Where overlap exists, this document focuses on the diagnosis and treatment of congenital valve disease when it differs from acquired valve disease, whether because of anatomic differences, presence of concomitant lesions, or differences to consider given the relatively young age of patients with ACHD. This guideline is not intended to apply to children (<18 years of age) with CHD or adults with acquired VHD, heart failure (HF), or other cardiovascular disease.The prevalence of ACHD is growing because of the success of pediatric cardiology and congenital cardiac surgery in diagnosing and treating congenital heart defects in children. Improved survival to adulthood is most striking for those with the most severe disease, with survival to age 18 years now expected for 90% of children diagnosed with severe CHD.S1.4-3–S1.4-5 Patients with ACHD are a heterogeneous population, both in underlying anatomy and physiology, as well as surgical repair or palliation. Consequently, although the prevalence of ACHD is increasing, the population of patients with a given congenital abnormality or specific repair may be relatively small.S1.4-3,S1.4-6–S1.4-8Patients with CHD are not cured of their disease after successful treatment in childhood. Almost all patients with ACHD will have sequelae of either their native CHD or its surgical repair or palliation, although these sequelae can take decades to manifest. The heterogeneity of the population and the long symptom-free intervals constrain the ability to generate data applicable across the population of ACHD or to adults with specific lesions or repairs. Despite the difficulty in studying ACHD populations, there is a growing body of high-quality data in these patients to guide the care of this relatively “new” population, and whenever feasible, these data were used to develop recommendations. Recommendations are made based on the available data; however, when important clinical issues lacked data, first principles, extrapolation from data in other populations, and expert consensus are used to guide care. Patients with ACHD may have concomitant disease to which other existing guidelines apply, such as coronary artery disease, HF, and arrhythmias. The data from acquired heart disease populations may apply to some patients with ACHD, and those circumstances are acknowledged in these recommendations and referenced accordingly.Patients with ACHD who are cared for in ACHD centers have better outcomes than those cared for in centers without ACHD expertise,S1.4-9 and this need for specialized care is noted throughout the guideline. These recommendations are intended to provide guidance to a wide variety of providers caring for patients with ACHD, including general, pediatric, and ACHD cardiologists, as well as surgeons, primary care providers, and other healthcare providers.In developing the 2018 ACHD guideline, the writing committee reviewed previously published guidelines and related scientific statements. Table 2 contains a list of publications and scientific statements deemed pertinent to this writing effort; it is intended for use as a resource and does not repeat existing guideline recommendations.Table 2. Associated Guidelines and StatementsTitleOrganizationPublication Year (Reference)Guidelines SyncopeACC/AHA/HRS2017S1.4-10 Supraventricular tachycardiaACC/AHA/HRS2015S1.4-11 Cardiopulmonary resuscitation and emergency cardiovascular care—Part 8: postcardiac arrest careAHA2015S1.4-12 Non-ST-elevation acute coronary syndromesAHA/ACC2014S1.4-13 Perioperative cardiovascular evaluation and noncardiac surgeryACC/AHA2014S1.4-14 Atrial fibrillationAHA/ACC/HRS2014S1.4-15 Stable ischemic heart diseaseACC/AHA/ACP/AATS/PCNA/SCAI/STS2014,S1.4-162012S1.4-17 Assessment of cardiovascular riskACC/AHA2014S1.4-18 Blood cholesterol to reduce atherosclerotic cardiovascular risk in adultsACC/AHA2014S1.4-19 Overweight and obesity in adultsAHA/ACC/TOS2014S1.4-20 Lifestyle management to reduce cardiovascular riskAHA/ACC2014S1.4-21 Valvular heart diseaseAHA/ACC2017S1.4-22 High blood pressure in adultsACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA2017S1.4-23 Aortic valve and ascending aortaSTS2013S1.4-24 ST-elevation myocardial infarctionACC/AHA2013S1.4-25 Heart failureACC/AHA/HFSA2017S1.4-26 Device-based therapy for cardiac rhythm abnormalitiesACC/AHA/HRS2012S1.4-27 Coronary artery bypass graft surgeryACC/AHA2011S1.4-28 Percutaneous coronary interventionACC/AHA/SCAI2011S1.4-29 Secondary prevention and risk reduction therapyAHA/ACC2011S1.4-30 Cardiovascular disease in womenAHA/ACC2011S1.4-31 Grown-up congenital heart diseaseESC2010S1.4-32 Thoracic aortic diseaseACC/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM2010S1.4-33 Adult congenital heart diseaseCCS2010S1.4-34 Infective endocarditisESC2009S1.4-35Scientific statements Imaging for patients with transposition of the great arteriesASE2016S1.4-36 Cardiac chamber quantification by echocardiographyASE2015S1.4-37 Consensus on arrhythmia management in ACHDPACES/HRS2014S1.4-38 Imaging for patients with repaired tetralogy of FallotASE2014S1.4-39 Thoracic aortic diseaseCCS2014S1.4-40 Promotion of physical activity for children and adults with CHDAHA2013S1.4-41 Neurodevelopmental outcomes in children with CHDAHA2012S1.4-42 Pregnancy in women with heart diseaseESC2011S1.4-43 Transition to adulthood for adolescents with CHDAHA2011S1.4-44 Pulmonary hypertensionACC/AHA2009S1.4-45 Prevention of infective endocarditisAHA2007S1.4-46AATS indicates American Association for Thoracic Surgery; ABC, Association of Black Cardiologists; ACC, American College of Cardiology; ACHD, adult congenital heart disease; ACP, American College of Physicians; ACPM, American College of Preventive Medicine; ACR, American College of Radiology; AGS, American Geriatrics Society; AHA, American Heart Association; APhA, American Pharmacists Association; ASA, American Stroke Association; ASE, American Society of Echocardiography; ASH, American Society of Hypertension; ASPC, American Society of Preventive Cardiology; CCS, Canadian Cardiovascular Society; CHD, congenital heart disease; ESC, European Society of Cardiology; HFSA, Heart Failure Society of America; HRS, Heart Rhythm Society; NMA, National Medical Association; PACES, Pediatric and Congenital Electrophysiology Society; PCNA, Preventive Cardiovascular Nurses Association; SCA, Society of Cardiovascular Anesthesiologists; SCAI, Society for Cardiovascular Angiography and Interventions; SIR, Society of Interventional Radiology; STS, Society of Thoracic Surgeons; SVM, Society for Vascular Medicine; and TOS, The Obesity Society.1.5. AbbreviationsAbbreviationMeaning/PhraseAAOCAanomalous aortic origin of the coronary arteryACHDadult congenital heart diseaseAPanatomic and physiologicalARaortic regurgitationASDatrial septal defectAVSDatrioventricular septal defectBAVbicuspid aortic valveCCTcardiac computed tomographyCCTGAcongenitally corrected transposition of the great arteriesCHDcongenital heart diseaseCMRcardiovascular magnetic resonanceCoAcoarctation of the aortaCPETcardiopulmonary exercise testCTcomputed tomographyCTAcomputed tomography angiographyd-TGAdextro-transposition of the great arteriesECGelectrocardiogramERCEvidence Review CommitteeGDMTguideline-directed management and therapyHFheart failureICDimplantable cardioverter-defibrillatorIEinfective endocarditisLVleft ventricularLVOTleft ventricular outflow tractPApulmonary arteryPAHpulmonary arterial hypertensionPDApatent ductus arteriosusPRpulmonary regurgitationPSpulmonary stenosisQp:Qspulmonary–systemic blood flow ratioRVright ventricularRVOTright ventricular outflow tractSCDsudden cardiac deathTEEtransesophageal echocardiographyTGAtransposition of the great arteriesTOFtetralogy of FallotTRtricuspid regurgitationTTEtransthoracic echocardiographyVHDvalvular heart diseaseVSDventricular septal defect2. Background and Pathophysiology2.1. Anatomic and Physiological TermsThe International Society for Nomenclature of Pediatric and Congenital Heart Disease (also known as the Nomenclature Working Group) defined, codified, mapped, and archived examples of nomenclatures and developed standards for terminology.S2.1-1–S2.1-5 The International Paediatric and Congenital Cardiac Code (IPCCC) nomenclature for anatomic lesions and repairs is used in this guideline (http://ipccc.net).S2.1-62.2. Severity of ACHDIn a patient with CHD, severity of disease is determined by native anatomy, surgical repair, and current physiology. Prior documents, including the 2008 ACHD guideline,S2.2-1 relied primarily on anatomic classifications to rank severity of disease. However, patients with the same underlying anatomy may have very different repairs and experienced variable physiological consequences of those repairs. For example, a patient with tetralogy of Fallot (TOF) after a valve-sparing primary repair may have excellent biventricular function with normal exercise capacity and no arrhythmias, whereas another patient of the same age with TOF may have had palliative shunting followed by a transannular patch repair resulting in severe pulmonary regurgitation (PR) with right ventricular (RV) enlargement, biventricular dysfunction, and ventricular tachycardia. To categorize disease severity in CHD in a more comprehensive way, the writing committee developed an ACHD Anatomic and Physiological (AP) classification system (Tables 3 and 4) that incorporates the previously described CHD anatomic variables as well as physiological variables, many of which have prognostic value in patients with ACHD.Table 3. Physiological Variables as Used in ACHD AP ClassificationVariableDescriptionAortopathyAortic enlargement is common in some types of CHD and after some repairs. Aortic enlargement may be progressive over a lifetime. There is no universally accepted threshold for repair, nor is the role of indexing to body size clearly defined in adults, as is done in pediatric populations. For purposes of categorization and timing of follow-up imagingS2.2-2–S2.2-4: Mild aortic enlargement is defined as maximum diameter 3.5–3.9 cm Moderate aortic enlargement is defined as maximum diameter 4.0–4.9 cm Severe aortic enlargement is defined as maximum diameter ≥5.0 cmArrhythmiaArrhythmias are very common in patients with ACHD and may be both the cause and consequence of deteriorating hemodynamics, valvular dysfunction, or ventricular dysfunction. Arrhythmias are associated with symptoms, outcomes, and prognosis,S2.2-5–S2.2-8 thus are categorized based on presence and response to treatment. No arrhythmia: