Adult Congenital Heart Disease E-Book

• Herausgeber: John Wiley & Sons
• Kategorie: Fachliteratur
• Serie: American Heart Association Clinical Series
• Sprache: Englisch

Seitenzahl: 461

Veröffentlichungsjahr: 2011

Beschreibung

• Guides practicing physicians in the practical aspects of how to diagnose and treat patients with congenital heart disease
• Reviews the most common congenital cardiac anomalies seen in practice
• Focuses on both clinical evaluation and diagnostic imaging modalities as well as practical management issues, as well as when to refer patients to tertiary care centres
• Each chapter is preceded by a case study to exemplify the issues which may be challenging in practical management

Leseprobe

Contents

Contributors

Preface

Foreword

Chapter 1 Secundum atrial septal defect

Embryology and anatomy

Pathophysiology

Natural history

Diagnosis

Treatment

Patient follow-up

References

Chapter 2 Atrioventricular septal defects

Case #1

Case #2

Case discussion

Partial AVSD

Associated anomalies

Complete atrioventricular septal defect

Patient follow-up

Case #1

Case #2

References

Chapter 3 Pulmonary stenosis/right ventricular outflow tract obstruction

Introduction

Valvular pulmonary stenosis

Subvalvular pulmonary stenosis

Supravalvular pulmonary stenosis

Case

Summary

References

Chapter 4 Ventricular septal defect

Anatomy and pathophysiology

Practical approach to VSD in adults

Indication for intervention

Prognosis

Conclusion

Outcome of case

54 References

Chapter 5 Pulmonary arterial hypertension in Eisenmenger Syndrome

Discussion

The pathophysiology and genetics of PAH in ES

The evaluation of PAH in ES

Managing ES

Disease-targeting therapies

Case study

References

Chapter 6 Congenitally corrected transposition of the great arteries

Definition

Terminology

Incidence

Presentation

Assessment and investigations

Management

Medical management issues

Case study

References

Chapter 7 Left ventricular outflow tract obstruction

General considerations

Valvular stenosis

Subvalvular aortic stenosis

Supravalvular stenosis

Case conclusion

References

Chapter 8 Coarctation of the aorta and aortic disease

Introduction

Aortic embryology and development

Coarctation of the aorta

Additional medical considerations

Aortopathy

Connective tissue disorders

Case summary

References

Chapter 9 Transposition of the great arteries after a Mustard atrial switch procedure

Background

Recommendation for follow-up in clinical practice

Case study

Conclusion

References

Chapter 10 Tetralogy of Fallot

Introduction

Anatomy

Surgical repair

Long-term complications after surgical repair

Management of late problems after surgical repair

Prevention of late problems after surgical repair

Case study

Synopsis

References

Chapter 11 Single ventricle physiology

Introduction

Incidence

Etiology

Key components of morphology

Initial presentation in childhood

Early palliative procedures

Subtypes of single ventricle circulations

Presentation in adulthood

Long-term outcome in adulthood

Long-term implications of a Fontan circulation

Case study

References

Chapter 12 Ebstein’s anomaly

Background

Pathology, genetics, and classification

Clinical features

Associated cardiac lesions

Diagnosis

Management

Catheter ablation and arrhythmia intervention

Surgical indications and options

Postoperative findings

Prognosis

Conclusions

Case study

References

Chapter 13 Imaging in adult congenital heart disease

Imaging modalities

Specific congenital cardiac lesions

Case outcome

References

Chapter 14 The chest x-ray in congenital heart disease

The bones

Extrapulmonary soft tissue densities

The atria

References

Chapter 15 Arrhythmias in congenital heart disease

Introduction

Treatment of existing arrhythmias

Risk of sudden death due to arrhythmias

Prevention of arrhythmias

Case study

References

Chapter 16 Pregnancy and contraception

Introduction

Global risk assessment

High-risk lesions which may preclude pregnancy

Pregnancy and the woman with congenital heart disease: a lesion-specific approach

Pregnancy and the woman with congenital heart disease: additional considerations

Management of labor and delivery

Contraception

Case study recommendations

References

Index

Author Disclosure Table

To Jane Somerville, who taught so many of us about congenital heart disease; for inspiring me to follow a different path.

This edition first published 2009, © 2009 American Heart Association

American Heart Association National Center, 7272 Greenville Avenue, Dallas, TX 75231, USA

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Library of Congress Cataloging-in-Publication Data

Adult congenital heart disease/edited by Carole Warnes.

p.; cm. – (The AHA clinical series)

Includes bibliographical references.

ISBN 978-1-4051-7820-4

1. Congenital heart disease. I. Warnes, Carole A. II. American Heart Association. III. Series.

[DNLM: 1. Heart Defects, Congenital–Case Reports. 2. Adult. WG 220 A2445 2008]

RC687.A452 2008

616.1’2043-dc22

Contributors

Editor

Carole Warnes,MD

Mayo Clinic

Rochester, MN

USA

Contributors

Naser M. Ammash,MD

Division of Cardiovascular Diseases and Internal Medicine

Mayo Clinic and Mayo Foundation

Rochester, MN

USA

Craig S. Broberg,MD, FACC

Director, Adult Congenital Heart Disease Program

Assistant Professor

Division of Cardiovascular Medicine

Oregon Health and Science University

Portland, OR

USA

Frank Cetta,MD

Divisions of Pediatric Cardiology and Cardiovascular Diseases

Departments of Pediatrics and Medicine

Mayo Clinic College of Medicine

Rochester, MN

USA

Jack M. Colman,MD

Toronto Congenital Cardiac Centre for Adults

Peter Munk Cardiac Centre

University Health Network and Mount Sinai Hospital

University of Toronto

Toronto

Canada

Heidi M. Connolly,MD

Mayo Clinic

Rochester, MN

USA

Barbara J. Deal,MD

Feinberg School of Medicine

Northwestern University

Department of Cardiology

Children’s Memorial Hospital

Chicago, IL

USA

Elyse Foster,MD

Director, Echocardiography Laboratory

Professor of Clinical Medicine

Araxe Vilensky Endowed Chair in Medicine

Department of Medicine; Cardiology

University of California

San Francisco, CA

USA

Michael A. Gatzoulis,MD, PhD, FACC, FESC

Adult Congenital Heart Centre and Centre for Pulmonary Hypertension

Royal Brompton Hospital, and National Heart and Lung Institute

Imperial College, London, UK

Michelle Z. Gurvitz,MD

Departments of Pediatrics and Medicine

Seattle Children’s Hospital and University of Washington Medical Center

University of Washington School of Medicine

Seattle, WA

USA

Katy Lease,MD

University of California

Department of Medicine

Division of Cardiology

San Francisco, CA

USA

Zeksen Lim,MBChB, MRCP

The Congenital Cardiac Unit

Southampton University Hospital

Southampton General Hospital

Southampton

UK

Folkert Meijboom,MD, PhD

Department of Cardiology and Pediatrics

University Medical Centre Utrecht Utrecht,

The Netherlands

Kevin Owusu-Ansah,MBChB, BSc (Hons)

The Congenital Cardiac Unit

Southampton University Hospital

Southampton General Hospital

Southampton

UK

Joseph K. Perloff,MD

Streisand/American Heart Association

Emeritus

USA

Sabrina D. Phillips,MD, FACC

Division of Cardiovascular Diseases and Internal Medicine

Mayo Clinic

Rochester, MN

USA

Candice K. Silversides,MS, MD, FRCPC

Assistant Professor

University of Toronto Staff Cardiologist and Echocardiographer

Toronto Congenital Cardiac Center for Adults

Toronto General Hospital/University Health Network

Toronto

Canada

Samuel C. Siu,MD, SM, FRCPC, FACC, FASE

City-Wide Chief of Cardiology

London Teaching Hospitals Gunton Professor of Medicine

Divisional Chair of Cardiology Schulich School of Medicine and Dentistry, University of Western Ontario

University Hospital, London Health Sciences Centre

Ontario

Canada

Lorna Swan,MB ChB, MRCP, MD

Royal Brompton Hospital

London

UK

Judith Therrien,MD

Department of Medicine

MAUDE Unit, McGill University

Montreal, Quebec

Canada

Sara A. Thorne,MBBS, MD, FRCP

University of Bermingham

Bermingham

UK

Gruschen R. Veldtman,MB ChB, MRCP

The Congenital Cardiac Unit

Southampton University Hospital

Southampton General Hospital

Southampton

UK

Rachel M. Wald,MD

Toronto Congenital Cardiac Center for Adults

Peter Munk Cardiac Centre

University Health Network and Mount Sinai Hospital

University of Toronto

Toronto

Canada

Gary Webb

Philadelphia Adult Congenital Heart Center

University of Pennsylvania

Philadelphia, PA

USA

Preface

The last fifty years have witnessed dramatic changes in the world of congenital heart disease; innovative cardiac surgeries, noninvasive imaging, and intensive care have all resulted in the successful survival of the majority of babies born with congenital heart disease. Now, there are approximately one million adults in North America with congenital heart disease, some of whom have had prior surgery and others who were surprised to learn as adults that they were born with heart disease. Although there are now more adults than children with congenital heart disease, the medical community has been ill-prepared to deal with their complex problems. The American College of Cardiology/American Heart Association have recently recognized the importance of this patient population by publishing guidelines to help medical practitioners manage some of their problems. The aim of this book is to offer further practical advice to physicians about common congenital anomalies and associated complications seen frequently in practice.

I believe our best learning experiences result from our clinical cases, and so each chapter of this book begins with a common clinical scenario related to each anomaly. This is followed by a description of the anatomy, features of the clinical diagnosis, a discussion of the imaging modalities, and appropriate treatment strategies. Each chapter then concludes with a discussion about the treatment used for each case and the outcome that resulted. Separate chapters on arrhythmias and imaging are also included.

The authors are an international group of experts in their field, and their contributions are very much appreciated. I hope the readers will benefit from the wealth of clinical experience included herein.

Carole Warnes, MD

Foreword

The strategic driving force behind the American Heart Association’s mission of reducing disability and death from cardiovascular diseases and stroke is to change practice by providing information and solutions to health care professionals. The pillars of this strategy are Knowledge Discovery, Knowledge Processing, and Knowledge Transfer. The books in the AHA Clinical Series, of which Adult Congenital Heart Disease is included, focus on high-interest, cuttingedge topics in cardiovascular medicine. This book series is a critical tool that supports the AHA mission of promoting healthy behavior and improved care of patients. Cardiology is a rapidly changing field and practitioners need data to guide their clinical decision-making. The AHA Clinical Series serves this need by providing the latest information on the physiology, diagnosis, and management of a broad spectrum of conditions encountered in daily practice.

Rose Marie Robertson, MD, FAHA

Chief Science Officer, American Heart Association

Elliott Antman, MD, FAHA

Director, Samuel A. Levine Cardiac Unit,

Brigham and Women’s Hospital

Chapter 2

Atrioventricular septal defects

Frank Cetta

Case #1

A 17-year-old girl born with partial atrioventricular septal defect (AVSD) had closure of the primum atrial septal defect (ASD) and repair of a cleft in the anterior leaflet of the mitral valve when she was 18 months of age. She did well and her growth and development were normal. She participated in high school sports and had no limitations. It was noted several years prior to the current presentation that she had developed a systolic ejection murmur. Echocardiography demonstrated the images shown in Fig. 2.1. That echocardiogram also demonstrated trivial mitral valve regurgitation and mild aortic valve regurgitation.

The echocardiograph in Fig. 2.1 demonstrates tissue in the left ventricular outflow tract (LVOT) that represents accessory connections from the anterior leaflet of the mitral valve to the septum.

Case #2

A 58-year-old woman originally presented at age 45 years with progressive dyspnea on exertion. She was an aerobics instructor at the time and noticed that her workout routine had become progressively more difficult over the previous 3–4 years. She denied any chest pains, palpitations, or other symptoms. She had never had cardiac rhythm issues. Her work-up 13 years before included a chest x-ray that demonstrated cardiomegaly. This prompted an echocardiogram that showed a large primum ASD and moderate mitral valve regurgitation. At that time, she underwent repair of a primum ASD and closure of a cleft in the anterior leaflet of the mitral valve. It was noted immediately postoperatively that there was mild narrowing of the LVOT. A soft systolic ejection murmur was present, and Doppler echocardiography demonstrated a mean gradient of 12 mm Hg across the LVOT. She had mild residual mitral valve regurgitation.

Fig. 2.1 Parasternal long axis projection demonstrating a subaortic membrane (arrow) that developed in a teenager, 15 years after repair of partial AVSD.

Now, at age 58 years, she has not seen a cardiologist for 5 years. Her primary care physician noted a loud systolic ejection murmur during a routine physical exam. This prompted re-evaluation in an adult congenital heart disease clinic. She has two systolic murmurs. The first is a harsh 3/6 ejection murmur best at the mid left sternal border radiating toward the right upper sternal border. There is no ejection click. The second heart sound is physiologically split. The second murmur is a 2/6 harsh holosystolic murmur best at the apex radiating to the left axilla. She has retired from her job as an aerobics instructor since her previous cardiology evaluation. She currently lives a more sedentary lifestyle and does not note any significant limitations. She denies symptoms of palpitations or chest pain.

Echocardiographic examination at this time demonstrates severe LVOT obstruction with a mean gradient of 60 mm Hg. There is mild aortic valve regurgitation and moderate mitral valve regurgitation. The anterior leaflet of the mitral valve is markedly thickened and, during systole portions of the anterior leaflet, appears to obstruct the left ventricular outflow tract (Fig. 2.2).

Fig. 2.2 Intraoperative transesophageal echocardiogram performed prior to cardiopulmonary bypass from a 58-year-old woman with a history of repair of partial AVSD and now with LVOT obstruction due to a combination of septal hypertrophy and redundant accessory mitral attachments.

Case discussion

Progressive LVOT obstruction occurs in up to 15% of patients after repair of partial AVSD. It occurs more frequently in patients with the “partial” form of AVSD than in patients with the “complete” form. Several factors contribute to this anatomic substrate. The LVOT in AVSD is more elongated than in normal hearts, displaying the so-called “gooseneck deformity.” In these hearts, the distance from the aortic valve to the cardiac apex is longer than the distance from the mitral valve to the apex (in normal hearts, these distances are roughly equal; Fig. 2.3). In addition, subaortic membranes and ridges may develop de novo in this area. Accessory mitral valve tissue can also contribute to subaortic obstruction. The papillary muscle positions may be rotated anteriorly in AVSD, contributing to outflow obstruction. For these reasons, after “reparative” surgery, these patients require meticulous and lifelong surveillance for development/progression of LVOT obstruction as well as development of aortic valve regurgitation and progression of mitral valve regurgitation.

NOMENCLATURE (synonyms):

Atrioventricular Septal Defects (AVSD)Atrioventricular Canal Defects (AV Canal)Endocardial Cushion Defects

Fig. 2.3 (Diagrams) In the normal heart, the distance from the apex to the aortic annulus and the distance from the apex to the mitral annulus are roughly equal. In contrast, in patients with AVSD, the distance from the apex to the aortic annulus is greater than the distance from the apex to the mitral annulus. (With permission from Robert Anderson, MD) This occurs because the aortic valve is “sprung” anteriorly. (Right) Pathologic specimen demonstrating the anteriorly displaced aortic valve (arrow) in complete AVSD. (Bottom) Two-dimensional echocardiograph from a subcostal frontal projection demonstrating the elongated LVOT “gooseneck.”

FORMS OF AVSD:

Complete:Common AV valve+large primum ASD+large inlet ventricular septaldefect (VSD)Partial:Primum ASD+cleft anterior leaflet of the mitral valve

This group of lesions will be referred to in this chapter as “atrioventricular septal defects” (AVSDs). AVSDs are anomalies that have a defect of the atrioventricular septum and a variety of abnormalities of the atrioventricular valves. AVSDs are divided into “partial” and “complete” forms. In “partial” AVSD, a primum ASD is always present and there are two distinct mitral and tricuspid valve annuli. The mitral valve is always cleft. In “complete” AVSD, a primum ASD is contiguous with an inlet ventricular septal defect (VSD) and a common atrioventricular valve has a single annulus. Several other subclassifications have been used to describe AVSDs. “Transitional” AVSD is a subtype of partial AVSD. This term is used when a partial AVSD also has a small inlet VSD that is partially occluded by dense chordal attachments to the ventricular septum. “Intermediate” AVSD is a subtype of complete AVSD that has distinct right and left atrioventricular valve orifices despite having only one common annulus. These separate orifices are referred to as “right” and “left” atrioventricular valve orifices rather than “tricuspid” and “mitral.” This description is also used after repair of complete AVSD. Rather than relying on the terminology of these subtypes, the clinician, echocardiographer, and surgeon should communicate by simply describing the anatomy and shunting observed (Fig. 2.4) [1]. Two-dimensional echocardiography is the primary imaging technique for diagnosis of AVSD [2–4]. It is particularly useful for delineating the morphology of the atrioventricular valves.

Partial AVSD

Pathology

In partial AVSD, the mitral and tricuspid annuli are separate. The most frequent form of partial AVSD consists of a primum ASD and a cleft anterior mitral valve leaflet. Most primum ASDs are large and located anteroinferior to the fossa ovalis. The defect is bordered by a crescentic rim of atrial septal tissue posterosuperiorly and by mitral–tricuspid valvular continuity anteroinferiorly.

The mitral and tricuspid valves achieve the same septal insertion level because the mitral annulus is displaced toward the apex. The defect imparts a “scooped-out” appearance to the inlet ventricular septum, and the distance from the mitral annulus to the left ventricular apex is less than the distance from the aortic annulus to the apex (Fig. 2.3).

The cleft in the anterior mitral leaflet is usually directed toward the midportion of the ventricular septum, along the anteroinferior rim of the septal defect (Fig. 2.5). In contrast, isolated mitral clefts (not otherwise associated with AVSD) are directed toward the aortic valve annulus [5]. The mitral orifice is triangular, rather than elliptical as in a normal heart, and resembles a mirrorimage tricuspid orifice. The cleft mitral valve usually is regurgitant and, with time, becomes thickened and exhibits secondary hemodynamic alterations in morphology that resemble mitral valve prolapse.

Fig. 2.4 Diagram depicting the physiologic and anatomic similarities and differences of the different forms of AVSD.

Clinical presentation

The child with partial AVSD is usually asymptomatic. Frequently, the lesion is detected at a young age because of a murmur. In the current era, the primum ASD is closed and the cleft in the mitral valve is addressed usually by 2 years of age. Surgical intervention in a very young child may be suboptimal if the cleft cannot be adequately closed without creating hemodynamically important mitral stenosis. If the patient with partial AVSD escapes diagnosis in childhood, then presentation in adulthood occurs due to symptoms of exercise intolerance, dyspnea on exertion, or palpitations from a new atrial arrhythmia. The patients may exhibit the typical physical exam findings of an ASD (systolic ejection murmur at the left upper sternal border, a widely split and fixed second heart sound, and a diastolic rumble along the lower left sternal border from increased flow across the tricuspid valve). The diagnosis may also be serendipitous when a chest x-ray demonstrates cardiomegaly, an electrocardiogram demonstrates left axis deviation, or an echocardiogram is performed. A murmur of mitral regurgitation (due to the cleft anterior leaflet) may also prompt echocardiographic evaluation. Rarely, mitral stenosis will develop in an adult with unrepaired partial AVSD. These patients usually have a single left ventricular papillary muscle.

Fig. 2.5 (Top) Pathologic specimen demonstrating a cleft (arrow) in the anterior mitral leaflet. (Bottom) Intraoperative transesophageal echocardiogram demonstrating a large primum ASD in partial AVSD.

Once detected, repair of partial AVSD is typically recommended due to volume overload of the right-sided chambers caused by the left-to-right shunt at atrial level. In addition, closure of the mitral cleft is indicated to hopefully halt progression of mitral regurgitation. Echocardiography performed in an imaging laboratory experienced with children and adults with congenital heart is preferred. Electrocardiography will demonstrate left axis deviation in at least two-thirds of patients. Chest radiographs may demonstrate cardiomegaly with increased pulmonary vascularity. The role of cardiac catheterization is limited to adult patients if concern exists that pulmonary vascular resistance is elevated. Typically, one would prefer pulmonary arteriolar resistance to be less than 6 units (m2) to consider safe repair. If baseline resistance is elevated above this value but reactivity with provocative testing in the catheterization laboratory is demonstrated, then cautious postoperative care including use of nitric oxide may be indicated. In patients age 40 years and older, noninvasive assessment for coronary artery disease is typically performed prior to surgery for the congenital cardiac defect. Coronary angiography may also be performed if these patients are having hemodynamic catheterization performed. Primum ASDs are not amenable to closure with transcatheter devices.

Echocardiographic evaluation of partial AVSD

Echocardiographic evaluation of a patient with partial AVSD needs to include assessment of right atrial and right ventricular sizes. Volume overload will produce right atrial and right ventricular dilation early in childhood. Right ventricular volume estimation should be made from multiple imaging planes due to the inherent flaws in this assessment. The finding of ventricular septal flattening is useful for assessment of right ventricular volume overload; however, its utility in prediction of right vetricular pressure in this clinical setting has been questioned [6].

The internal cardiac crux is the most consistent echocardiographic imaging landmark, typically imaged in the apical four-chamber imaging plane. The primum ASD is seen as an absence of the lower atrial septum. The size of the primum ASD is made reliably from this imaging position (Fig. 2.5). Accurate visualization of the cardiac crux also permits assessment of the atrioventricular valves. Several two-dimensional echocardiographic features are shared by all forms of AVSD: deficiency of a portion of the inlet ventricular septum, inferior displacement of the atrioventricular valves, and attachment of a portion of the left atrioventricular (mitral) valve to the septum. The atrioventricular valves are displaced toward the ventricles, with the septal portions inserting at the same level onto the crest of the ventricular septum. Therefore, in these defects, the two separate atrioventricular valve orifices are equidistant from the cardiac apex (Fig. 2.6).

Spectral and color flow Doppler hemodynamic assessment are useful to determine the severity of atrioventricular valve stenosis or regurgitation, and to quantitate right ventricular systolic pressure. Doppler echocardiography is not reliable for evaluating mitral stenosis in the setting of a primum ASD because a large interatrial communication will decompress pressure from the left atrium.

Fig. 2.6 Diagram depicting the normal inferior displacement of the septal leaflet of the tricuspid valve relative to the insertion point of the anterior mitral leaflet as compared with the relationship of the atrioventricular valves in AVSDs.

Other mitral valve abnormalities are typical with both the partial and complete forms of AVSD [1]. The most common abnormality, a cleft, is best visualized from the parasternal and subcostal short axis imaging planes. Rarely, a parachute or a double-orifice mitral valve also occurs.

Associated anomalies

The most common associated anomalies with partial AVSD are a secundum ASD and persistence of a left superior vena cava connecting to the coronary sinus. Less frequently, tetralogy of Fallot, double-outlet right ventricle, pulmonary valve atresia, and anomalous pulmonary venous connections are associated with complete AVSD but are less frequent with partial defects. In contrast, atrioventricular valve abnormalities and left ventricular hypoplasia are more frequent in two orifice atrioventricular connections. Coarctation of the aorta occurs with equal frequency in partial and complete AVSD [7–9].

Surgical treatment of partial AVSD

The objectives of surgical repair include closure of the interatrial communication and restoration and preservation of mital valve competence (Fig. 2.7). These objectives can be accomplished by careful approximation of the edges of the valve cleft [10]. This repair results in a two-leaflet valve. In an alternative technique, the left atrioventricular valve is considered a trileaflet valve, considering the cleft as a commissure. With this approach, the cleft remains unsutured and various annuloplastic sutures are placed to enable coaptation [11–13]. Long-term survival after surgical repair in childhood has been excellent, and cumulative 20-year survival of 95% has been reported. In 1995, the Mayo Clinic group reported a 6% early mortality for patients with partial AVSD who had surgical repair after 40 years of age [14]. Long-term issues in this group were uncommon, but continued surveillance is warranted for late arrhythmia. Postoperative echocardiographic surveillance is indicated at least every few years after surgery. Reoperation awaits at least 25% of patients due to progressive mitral valve regurgitation or development of left ventricular outflow tract obstruction [15].

Fig. 2.7 (Left) Pathology specimen of a heart with patch (arrow) closure of a primum ASD. In addition, the anterior leaflet of the mitral valve is thickened in the region of the cleft repair. (Right) Corresponding apical four-chamber echocardiograph.

Complete atrioventricular septal defect

Pathology

The complete form of AVSD is characterized by a large septal defect with interatrial and interventricular components and a common atrioventricular valve that spans the entire septal defect [16]. The septal defect extends to the level of the membranous ventricular septum, which is usually deficient or absent.

The common atrioventricular valve has five leaflets (a posterior bridging leaflet drapes over the inlet ventricular septum, two lateral leaflets, a right-sided anterior leaflet, and the so-called anterior bridging leaflet). The extent to which the anterior bridging leaflet actually straddles into the right ventricle varies considerably and has formed the basis for a classification system of complete AVSD into Rastelli types A, B, and C [17]. In the modern era, its clinical and surgical significance has become less important. The common atrioventricular valve may be divided into distinct right and left orifices by a tongue of tissue that connects the two bridging leaflets, representing the “intermediate” form of AVSD.

Clinical presentation of complete AVSD

The child with complete AVSD typically presents with a loud systolic ejection murmur or failure to thrive. This defect may have been detected during prenatal ultrasound screening due to the markedly abnormal apical four-chamber image. A child born with Down syndrome should have echocardiographic screening in the newborn period. Children with Down syndrome have a 40% incidence of congenital heart disease, and approximately 40% of these children will have an AVSD. Chest radiographs typically demonstrate cardiomegaly and increased pulmonary vascularity consistent with the large left-to-right shunt. Electrocardiographs typically demonstrate a superior frontal plane axis (extreme left-axis deviation) and voltage criteria for ventricular hypertrophy.

Children with complete AVSD usually have surgical repair at 3–6 months of age, depending on issues with growth and development. Children with Down syndrome may have persistent pulmonary hypertension despite early repair. Similarly, patients with complete AVSD who are not repaired in the first 9 months of life are likely to have persistent pulmonary hypertension.

Patients with complete AVSD followed in an adult congenital heart disease clinic typically had repair of the lesion in early childhood and require continued meticulous surveillance for development of hemodynamically important left AV valve regurgitation or stenosis. Some of the patients may require reoperation in adulthood. The left AV valve is frequently replaced, but the surgery should be performed by a congenital cardiac surgeon with expertise in the care of children and adults with congenital heart disease. The patient stands a better chance of having successful re-repair and preservation of the native left AV valve with an experienced congenital heart disease surgeon.

Currently, another group of patients with complete AVSD followed in adult congenital heart clinics are those who did not benefit from repair in childhood. Although born with a large left-to-right shunt, they developed irreversible pulmonary vascular obstructive disease and have Eisenmenger physiology as adults. Patients with pulmonary hypertension can be treated with pulmonary vasoactive agents, such as sildenafil, bosentan, or flolan, and subjective improvement in symptoms may occur. These patients also suffer from progressive left and right AV valve regurgitation as well as progressive biventricular systolic dysfunction. Survival for this subgroup of patients beyond the fifth decade has been reported but is rare. These patients require management of secondary erythrocytosis, urate nephropathy, hemoptysis, thromboembolic events, and usually succumb from arrhythmia. Consideration of these patients for heart–lung transplantation is controversial.

Echocardiographic assessment of complete AVSD

Two-dimensional echocardiography is the primary diagnostic tool for evaluation of complete AVSDs [18,19]. As described earlier, assessment of the internal cardiac crux from the apical and subcostal four-chamber projections provides excellent detail of the size and locations of defects in both the atrial and ventricular septa. Additional secundum ASDs, a fairly common associated finding, can be detected from the subcostal four-chamber coronal view and with clockwise rotation of the transducer from the subcostal sagittal imaging plane. The VSD is located posteriorly in the inlet septum. Both right-sided and left-sided components of the common atrioventricular valve are displaced toward the ventricles and are associated with variable deficiency of the inflow ventricular septum. Spectral and color Doppler serve as adjuncts to assess the sites of shunting, severity of atrioventricular valve regurgitation, and connections of the pulmonary veins. Anomalous pulmonary venous connections are rarely associated with complete AVSDs and can be assessed with two-dimensional and two-dimensional Doppler echocardiography from multiple imaging planes.

Other atrioventricular valve abnormalities

Double-orifice left atrioventricular valve occurs rarely in AVSDs. This abnormality occurs usually when two distinct right and left atrioventricular valve orifices are present. The combined effective valve area of a double-orifice valve is always less than the valve area of a single-orifice valve. This predisposes the valve to postoperative stenosis. Standard subcostal and parasternal short axis views usually demonstrate the double-orifice valve characteristics.

Another rare association with complete AVSD is a single left ventricular papillary muscle. Similar to the double-orifice valve, a single papillary muscle will reduce the effective valve area. In patients with a single left ventricular papillary muscle, valve repair may be compromised due to relative leaflet hypoplasia. Echocardiographic imaging techniques for this abnormality are similar to those for double-orifice left atrioventricular valves.

The term “unbalanced AVSD” has been applied when one ventricle and its corresponding atrioventricular valve are hypoplastic while the other ventricle receives the larger portion of the common atrioventricular valve. In this circumstance, the most common arrangement is a dominant right ventricle with a hypoplastic left ventricle. The left-sided component of the common atrioventricular valve may be stenotic after two-ventricle repair has been performed. Depending on the size of the diminutive ventricle, some of these patients may be best managed with a surgical strategy designed for patients with functional single-ventricle physiology. This would ultimately result in a Fontan operation [1].

Surgical repair of complete AVSD

The objectives of surgical repair include closure of interatrial and interventricular communications, construction of two separate and competent atrioventricular valves from available leaflet tissue, and repair of associated defects. Techniques for the surgical repair of complete AVSD have been standardized and are based on the use of a single patch or double patch (separate atrial and ventricular patches) to close the ASD and VSD and then reconstruction of the left atrioventricular valve as a bileaflet valve. Puga and McGoon have described these techniques in detail [20].

In contrast, other groups [12,21] consider the cleft of the left atrioventricular valve a true commissure and envision this valve as a trileaflet valve. On the basis of these concepts, Carpentier [11] prefers the two-patch technique. The left atrioventricular valve remains a trileaflet structure. In most centers, the two-patch technique has become the method of choice.

Clinical evaluation after repair of AVSD

Over the last four decades, surgical repair of AVSD has been one of the success stories in congenital heart disease. However, as with most congenital cardiac lesions, these patients require lifelong cardiology surveillance at centers that specialize in the care of adults with congenital heart disease. Patients who are doing well after repair of AVSD are typically seen every 2–3 years and have electrocardiographic and echocardiographic testing performed. Exercise treadmill testing is useful to periodically obtain objective evidence of patient fitness. Many of these patients are able to participate fully in sports activities. Pregnancy results for women with AVSD have been good [22,23], although a recent review indicated that atrial arrhythmia may complicate as many as 10% of pregnancies in women with AVSD [24]. It is generally recommended that women with unrepaired AVSD undergo repair prior to contemplating pregnancy, but in women with partial AVSD, pregnancy is usually well tolerated. Pregnancy is contraindicated in women with unrepaired AVSD who have Eisenmenger physiology.

Rarely, these patients will have hemodynamically significant residual shunts after surgery. These shunts are typically not amenable to closure with commercially available closure devices due to the proximity of the atrioventricular valves. If a patient with history of AVSD repair requires repeat surgery for atrioventricular valve surgery or relief of LVOT obstruction, this is best managed by a surgeon skilled in the care of children and adults with congenital heart disease.

Patient follow-up

Both of these cases illustrate a common consequence of repair of AVSD. In the first case,the patient was a small child at the time of the initial repair, and it is not surprising that residual LVOT obstruction developed once she was fully grown. The second case is illustrative of the fact that, even in an adult, progressive LVOT obstruction may occur after “successful” repair of partial AVSD. The surgical approach to both patients differed due to the etiology of the obstruction.

Case #1

This patient underwent repeat cardiac surgery for excision of the accessory mitral valvetissue. The mitral valve remained intact and competent. There was no change in the severity of mitral regurgitation as compared with her preoperative echocardiogram. Two years after that surgery, her echocardiogram demonstrated no residual LVOT obstruction, no aortic valve regurgitation, and only mild mitral valve regurgitation. She remained active and is currently a college student participating in intramural athletics.

Case #2

The cardiologist and congenital cardiac surgeon who cared for the patient believed that the abnormal morphology of the mitral valve was contributing to the LVOT obstruction, and it was anticipated that she would require mitral valve replacement with a mechanical prosthesis. However, at the time of surgery, an extended septal myectomy/myotomy was performed; in addition, fibrous tissue was peeled from the ventricular surface of the mitral valve (Fig. 2.8). The native mitral valve was preserved, and the patient left the operating room with no residual LVOT obstruction and only mild mitral regurgitation.

Fig. 2.8 A similar image to Fig. 2.2 from the same patient after septal myectomy/myotomy and peeling of fibrous tissue from the undersurface of the anterior mitral leaflet. This image demonstrates no residual obstruction. The patient’s mitral valve was preserved and she has only mild residual regurgitation.

References

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2. Seward JB, Tajik AJ, Hagler DJ. Two-dimensional echocardiographic features of atrioventricular canal defect. In: Lundström N-R, ed. Pediatric Echocardiography: CrossSectional, M-Mode and Doppler. New York: Elsevier/North Holland, 1980:197–206.

3. Silverman NH, Ho SY, Anderson RH, et al. Atrioventricular septal defect with intact atrial and ventricular septal structures. Int J Cardiol 1984;5:567–72.

4. Snider RA, Serwer GA, Ritter SB, eds. Defects in cardiac septation. In: Echocardiographyin Pediatric Heart Disease, 2nd edition. St. Louis: Mosby-Year Book, 1997:277–89.

5. di Segni E, Edwards JE. Cleft anterior leaflet of the mitral valve with intact septa: a study of 20 cases. Am J Cardiol 1983;51:919–26.

6. Nielsen JC, Kamenir SA, Ko HSH, Lai WW, Parness IA. Ventricular septal flattening at end systole falsely predicts right ventricular hypertension in patients with ostium primum atrial septal defects. J Am Soc Echocardiogr 2002;15:247–52.

7. Goel AK, Ganesan L, Edelstein M. Atrioventricular septal defect with cor triatriatum: case report and review of the literature. Pediatr Cardiol 1998;19:243–5.

8. LaCorte MA, Cooper RS, Kauffman SL, et al. Atrioventricular canal ventricular septal defect with cleft mitral valve: angiographic and echocardiographic features. Pediatr Cardiol 1982;2:289–95.

9. Silverman NH, Ho SY, Anderson RH, et al. Atrioventricular septal defect with intact atrial and ventricular septal structures. Int J Cardiol 1984;5:567–72.

10. Thiene G, Wenink ACG, Frescura C, et al. Surgical anatomy and pathology of the conduction tissues in atrioventricular defects. J Thorac Cardiovasc Surg 1981;82: 928–37.

11. Carpentier A. Surgical anatomy and management of the mitral component of atrioventricular canal defects. In: Anderson RH, Shinebourne EA, eds. Paediatric Cardiology. Edinburgh: Churchill Livingstone, 1978:477–90.

12. Piccoli GP, Wilkinson JL, Macartney FJ, et al. Morphology and classification of complete atrioventricular defects. Br Heart J 1979;42:633–9.

13. Aubert S, Henaine R, Raisky O, et al. Atypical forms of isolated partial atrioventricular septal defect increase the risk of initial valve replacement and reoperation. Eur JCardiothorac Surg 2005;28:223–8.

14. Bergin ML, Warnes CA, Tajik AJ, Danielson GK. Partial atrioventricular canal defect: Long-term follow-up after initial repair in patients >40 years old. J Am Coll Cardiol 1995;25:1189–94.

15. McGrath LB, Gonzalez-Lavin L. Actuarial survival, freedom from reoperation, and other events after repair of atrioventricular septal defects. J Thorac Cardiovasc Surg 1987;94:582.

16. Titus JL, Rastelli GC. Anatomic features of persistent common atrioventricular canal. In: Feldt RH, McGoon DC, Ongley PA, et al., eds. Atrioventricular Canal Defects. Philadelphia: WB Saunders, 1976:13–35.

17. Rastelli GC, Kirklin JW, Titus JL. Anatomic observations on complete form of persistent common atrioventricular canal with special reference to atrioventricular valves. Mayo Clin Proc 1966;41:296–308.

18. Minich LL, Snider AR, Bove EL, et al. Echocardiographic evaluation of atrioventricular orifice anatomy in children with atrioventricular septal defect. J Am Coll Cardiol 1992;19:149–53.

19. Seward JB, Tajik AJ, Edwards WD, Hagler DJ, eds. Congenital heart disease. In: Two-Dimensional Echocardiographic Atlas (Vol. 1). New York: Springer–Verlag, 1987:284–9.

20. Puga FJ, McGoon DC. Surgical treatment of atrioventricular canal. Mod Technics Surg 1980;26:1–13.

21. Studer M, Blackstone EH, Kirklin JW, et al. Determinants of early and late results of repair of atrioventricular septal (canal) defects. J Thorac Cardiovasc Surg 1982;84: 523–42.

22. Drenthen W, Pieper PG, van der Tuuk K, et al. Cardiac complications relating to pregnancy and recurrence of disease in the offspring of women with atrioventricular septal defects. Eur Heart J 2005;26:2581–7.

23. Zuber M, Gautschi N, Oechslin E, Widmer V, Kiowski W, Jenni R. Outcome of pregnancy in women with congenital shunt lesions. Heart 1999;81:271–5.

24. Drenthen W, Pieper PG, Roos-Hesselink JW, et al. Outcome of pregnancy in women with congenital heart disease. J Am Coll Cardiol 2007;49:2303–11.

Chapter 3

Pulmonary stenosis/right ventricular outflow tract obstruction

Elyse Foster and Katy Lease

A 67-year-old man with a history of congenital valvular pulmonary stenosis had a history of surgical pulmonary valvotomy at age 14. He was referred for evaluation of a heart murmur, and also had a history of hypertension, hyperlipidemia, and diabetes mellitus type II. At the initial evaluation, he was feeling well, with no cardiac symptoms, but did not exercise regularly. He was able to climb two flights of stairs but did report tiring easily on longer distances. The physical exam revealed an absent P2 component of the second sound and a mid-peaking systolic murmur in the left parasternal region with no diastolic murmur but was otherwise normal. Electrocardiogram revealed right ventricular hypertrophy with incomplete right bundle branch block. Echocardiogram showed right ventricular hypertrophy (Fig. 3.1) with preserved right ventricular systolic function. The pulmonary valve appeared thickened and there was a peak gradient of 61 mm Hg across the valve in parasternal views. Subcostal views revealed a peak gradient of 89 mm Hg. There was an associated late-peaking dynamic gradient in the right ventricular outflow tract reaching 25 mm Hg (Fig. 3.2). The main pulmonary artery appeared to be significantly dilated.

Introduction