Sulfonamides are the drug of choice for Norcadiosis, and a combination of three antibiotics including penicillin should be given for Actinomycosis. CHAPTER 7 Diseases of the myocardium and pericardium 324 Amoebic pericarditis Pathology Amoebiasis (caused by Entamoeba histolytica) occurs mainly i n endemic areas and in travelers from them (in whom the syndrome may appear years later). P ericardial complications are rare, but when they do occur, they carry a high mortality, esp ecially with delayed or missed diagnosis. The usual cause of amoebic pericarditis is extension from an amoebic liver abscess in the l eft lobe. Rarely, spread may also occur from the right lobe or disease may reach the perica rdium from an amoebic lung abscess. Clinical presentation There are two modes of presentation: 1. Hepatic presentation: an absc ess near the pericardium, which has not yet ruptured, can cause a pericardial friction rub, a nonpurulent pericar- dial effusion, and ECG/CXR signs of pericarditis. 2. Cardiac presentation: perforation of a liver abscess into the pericar- dium results in a purulent pericarditis. The onset can be acute, with shock and death within a short time, o r the onset may be gradual with signs of tamponade as a result of the pericardial \202 ui d. Diagnosis Diagnosis is dif \201 cult but should be suspected if, in a patient with a purul ent pericarditis and signs of cardiac failure, tenderness of the liver in the epi- gastrium is much more marked than the rest of the palpable liver. A high and immobile left hemidiap hragm detected by \202 uoroscopy or CT scan is also suggestive. De \201 nite diagnosis is by pericardiocentesis (which typically shows brown- ish \202 u id; the pus may simulate anchovy sauce) and serological testing for antibodies resulting fr om invasive amoebiasis ( \202 uorescent antibody test or amoebic enzyme immunoassay or amo ebic gel diffusion test). Treatment With hepatic presentation the pericardial disease resolves with successful treatm ent of the liver abscess. With cardiac presentation, treat with pericardial drainage and metro- nidazole. Constrictive pericarditis is an occasional complication. PERICARDITIS VS. MYOCARDIAL DISEASE 325 Constrictive pericarditis vs. restrictive myocardial disease It is dif \201 cult to separa te constrictive pericarditis from restrictive myocar- dial disease. The distinction is vita l, because pericardiectomy is one of the most satisfying operations in terms of cure. Point s of differentiation are as presented in Table 7.4. An exploratory thoracotomy is justi \201 ed if all of these tests fail to make a distinction between the two entities. Table 7.4 Comparison of constrictive pericarditis and restrictive myocardial disease Constriction Restriction \200 and TR \200 myocardial disease Murmur of MR Clinical History of prior pericardial disease, prior pericardial trauma, prior cardiac surgery Known in \201 ltrative ECG Normal Left axis deviation, LVH, Q waves, LBBB CXR Pericardial calci \201 cation No pericardial calci \201 cation \200 LVH \200 \200\234Speckled \200\235 appearance o f myocardium \200 \200 <8 cm/sec \200 \200 Echocardiogram Septal bounce Tissue Doppler Ea Normal LV systolic function (cid:116)8 cm/sec LV dysfunction Tissue Doppler Ea CT or MRI Pericardium (cid:116)3 mm Normal pericardium Endomyocardial biopsy Normal myocardium Evidence of in \201 latrative disease (i.e., amyloid, hemochromatosis) \200 \200 diffe rence between LVEDP and RVEDP \200 PAS >50 mmHg \200 (RVSP increases with inspiration, LVSP decreases with inspiration) \200 Dip and plateau >6 mmHg Right heart catheterization (RHC) Dip and plateau Ventricular interdependence PAS <50 mmHg CHAPTER 7 Diseases of the myocardium and pericardium 326 Pericardial \202 uid analysis Analyzes of pericardial effusion can establish the diagnosi s of viral, bacter- ial, TB, fungal, amoebic, and malignant pericarditis. The appearance of the pericardial \202 uid should be noted. The tests should be ordered according to the c linical presentation of the patient. However, the following routine samples are useful: Biochemistry sample for protein and LDH estimation to distinguish between and exudate and a transudate Microbiology specimen for mi croscopy, culture, and sensitivity testing Cytology specimen \200 The following tests are requested for the diagnosis of the speci \201 c forms of pericardi tis: \200 \200 Viral pericarditis \200\224PCR for cardiotropic viruses Purulent pericarditis \200\224Gram stain, at least 3 blood cultures of pericardial \202 uid for aerobes and anaerobes and bl ood cultures TB pericarditis \200\224staining for AFB; bedside inoculation of pericardial \202 uid into double-strength Kirschner transportation medium and culture; ADA level Funga l pericarditis \200\224microscopy and culture Amoebic pericarditis \200\224brownish pericar dial \202 uid with anchovy sauce appearance of pus Malignant effusion \200\224cytology an d tumor markers (e.g., CEA) \200 Pericardiocentesis See Chapter 1. FURTHER READING 327 Further reading Akashi YJ, Goldstein DS, Barbaro G, Ueyama T (2008). Takotsubo cardiomyopathy: a new form o f acute, reversible heart failure. Circulation 118(25):2754 \200\2232762. Dote K, Sato H, Ishihara M (1991). Myocardial stunning due to simultanous coronary spasms: a review of 5 cases. J Cardiol 21(2):203 \200\223214. Kuowski V, Kaiser A, von Hof K, et al. (2007). Apical and midventricular transient left ven tricu- lar dysfunction syndrome (tako-tsubo cardiomyopathy): frequency, mechanisms, and pro gnosis. Chest 132(3):809 \200\223816. Nishimura RA, Holmes DR Jr (2004). Clinical practice. Hypertrophic obstructive cardiomyopat hy. N Engl J Med 350(13):1320 \200\2231327. Watkins H, McKenna WJ (2005). The prognostic impact of septal myectomy in obstructive hyper - trophic cardiomyopathy. J Am Coll Cardiol 46:477. Wigle ED, Rakowski H, Kimball BP, Williams WG (1995). Hypertrophic cardiomyopathy. Clinical spectrum and treatment. Circulation 92(7):1680 \200\2231692. This page intentionally left blank 329 Chapter 8 Congenital heart disease Introduction 330 Assessment of patients with CHD 332 Speci \201 c signs in patients with C HD 336 Surgical operations for CHD 337 Percutaneous transcatheter interventions for CHD 341 Speci \201 c management issues 343 Atrial septal defect 346 Ventricular septal defect 346 Atrioventricular septal/canal defect (endocardial cushion defect) 346 Pulmonary stenosis 347 Left ventricular out \202 ow tract (LVOT) obstruction 347 Coarctati on of the aorta 347 Anomalous pulmonary venous drainage 348 Transposition of the great arte ries 348 Tetralogy of Fallot 349 Fontan patients 349 Congenitally corrected transposition o f the great arteries 350 Ebstein \200\231s anomaly of the tricuspid valve 350 Extracardiac complications 351 CHAPTER 8 Congenital heart disease 330 Introduction Congenital heart disease (CHD) is one of the most common congenital defects, o ccurring in approximately 0.6% \200\2230.8% of newborns. Advances in therapy have led to a dramatic improvement in outcome such that over 85% of infants, even with complex CHD, are e xpected to reach adoles- cence and early adulthood. As a result of the success of pediatric cardiology and surgery, the number of adults with C HD is greater than the number of pediatric cases. In addition, there are patients with stru ctural or valvular CHD who may present late during adulthood. As of 2000 there were roughly 485,000 American adults with moderate to very complex CHD and 300,000 with simple forms of CHD.1 Many of those with CHD have had palliative or reparativ e rather than corrective surgery and will require further cardiac operations and procedures . Role of specialist CHD centers \200 \200 \200 \200 Initial assessment of adults with known or suspected CHD Surgical and nonsurgical intervent ions, e.g., transcatheter closure ASD Continuing care of patients with moderate and complex CHD Advice and ongoing support for noncardiac surgery, pregnancy, and other medical illnes ses Training new specialists and evidence-based clinical decision-making Provide feedback o f late results to re \201 ne early treatment \200 Pediatric to adult care transition A smooth transition from the pediatric to the adult CHD specialist is essential (Box 8.1). This should be tailored to the individual patient with b uilt-in \202 exibility (see Table 8.1). Transfer to the adult service should occur at aro und 18 years of age. Patient education about diagnosis and speci \201 c health behavior, includ- ing contracept ion and pregnancy planning, and the need for further care and follow-up should be included. Patient pamphlets that include detailed diagrams of the individual cardiac defect, prior r epair if any, and relevant information on topics such as exercise and need for antibiotic p rophylaxis should be prepared for each patient. Treat adult CHD patients with respect (see Box 8.2 for various types of disease). Many prob lems or errors arise from arrogance or ignorance. The patients may often know more about th eir condition and its management than the emergency medical team they consult. Therefore, b e patient and listen. Patients are often accompanied by the parent(s) even well into their late teens or second or third decade. They can prove a great source of information and help ; keep them on your side. Get to know your local adult CHD center. Box 8.1 No patient with CHD should reach adulthood without a clear manage- ment plan. INTRODUCTION 331 Table 8.1 Disease complexity and hierarchy of care for adults with CHD Level 1 Exclusive care by specialist service, e.g., Eisenmenger syndrome, Fontan repairs, t ransposition of the great arteries, any condition with atresia in the name, Marfan \200\231 s syndrome Level 2 Shared care with interested adult cardiologist, e.g., coarctation of the aorta, atr ial septal defect, tetralogy of Fallot Level 3 Ongoing management by general adult cardiology service, e.g., mild pulmonary valve stenosis, postoperative atrial, or ventricular septal defect Information sources on adult congenital heart disease: 1. Dean \201 eld J, et al. (2003). Management of grown up congenital heart disease. European Society of Cardiology task force report. Eur Heart J 24;1035 \200\2231084. 2. British Cardiac Society (2002). Current needs and provision of service for adolescents and adults in the United Kingdom 2002. Heart 88(Su ppl I):1 \200\22314. 3. Connelly MS, Webb GD, Somerville J, et al. (1998). Canadian Consens us Conference on Adult Congenital Heart Disease. Can J Cardiol 14:395 \200\223452. Box 8.2 Congenital heart disease in adults Acyanotic lesions \200 \200 \200 Cyanotic lesions \200 Transposition of the great arteries Tetralogy of Fallot Fontan patients Congenitally correc ted transposition of the great arteries Severe Ebstein \200\231s anomaly of the tricuspid v alve Atrial septal defect Ventricular septal defect Complete atrioventricular septal defect Pulm onary stenosis Left ventricular out \202 ow tract obstruction Coarctation of the aorta Ano malous pulmonary venous drainage Ebstein \200\231s anomaly of the tricuspid valve \200 \200 \200 \200 CHAPTER 8 Congenital heart disease 332 Assessment of patients with CHD History \200 \200 \200 \200 \200 Family history of CHD Exposure to teratogens or toxins during pregnancy CHD suspected durin g pregnancy or at birth (ask the mother!!) History of prolonged childhood illnesses Prior i nterventions \200 Any previous hospitalizations for catheter or surgical-based interventions Names of previou s pediatric cardiologists and surgeons as well as hospital in which surgery, if any, was pe rformed Dental hygiene Current symptoms \200 \200 \200 \200 Shortness of breath on exertion? Ability to climb stairs, hills, walk on the \202 at, and distance covered? Shortness of breath while lying down? Chest pain? \200 \200 Syncopal episodes? Palpitations? \200 \200 \200 Assess functional capacity. Precipitating and relieving factors? Any associated symptoms? \200 Onset, duration Associated presyncope or chest pain? Ask patient to tap out rate and rhythm of palpitations. General evaluation (see also Box 8.3) \200 Chart the patient \200\231s height, weight, and blood pressure (both arms!) against standar d reference charts. Does the patient have an obvious syndrome? \200 Down syndrome (1/3 associated with CHD, especially atrioventricular septal defect) Williams syndrome (supravalvar aortic and pulmonary stenosis) Noonan \200\231s syndrome (dysplastic pulmonary valvular stenosis, hypertrophic cardiomyopathy) Turner \200\231s syndrome (coarc tation of the aorta/aortic valve stenosis) \200 Is the patient anemic or jaundiced? Are there any features to suggest infective endocarditi s? Is there evidence of poor oral hygiene with dental caries or infected gums? Any tattoos or body piercing? Are there scars consistent with prior surgical intervention(s)? Are dista l pulses delayed, absent, or reduced in amplitude and, if so, in what distribution? Liver s ize and pulsatility are barometers of right-sided pressures, \201 lling and function Club bing \200 \200 \200 \200 ASSESSMENT OF PATIENTS WITH CHD 333 Box 8.3 Systematic approach to auscultation of patient with CHD 1. Listen to the heart sounds. Do not assume heart will be left sided First heart sound \200 The \201 rst heart sound is usually heard as a single sound, but since mitral closure is loudest, it is best heard at the apex. A loud \201 rst heart sounds may be heard in mitra l stenosis or sometimes with an atrial septal defect (ASD). Soft \201 rst heart sounds ar e a feature of poor myocardial contractility or a long PR interval. Second heart sound \200 Fixed splitting in the presence of a signi \201 cant ASD and is best appreciated in the hi gh or mid left sternal border Accentuated in the presence of pulmonary hypertension Widely split following repair of tetralogy of Fallot, the second heart sound re \202 ects the rig ht bundle branch block (RBBB), characteristic of the postoperative ECG. \200 2. Check for systolic and diastolic murmurs. (Draw an imaginary line between the nipples). Murmurs loudest above nipple line \200 \200 \200 Systolic ejection. Arise from the right or left ventricular out \202 ow tract. If associat ed with a carotid or suprasternal thrill, usually from the left ventricular out \202 ow tr act. If an ejection click is heard, the murmur is valvular in origin. Ejection click of aor tic valve stenosis is best heard at the apex. Ejection systolic murmur best heard in the in terscapular region and associated with a left thoracotomy may indicate turbulence across a prior coarctation repair. \200 \200 Murmurs loudest below nipple line \200 Pansystolic and arise from mitral/tricuspid regurgitation or from a ventricular septal defe ct (VSD). A \200\234to and fro \200\235 murmur best heard at the upper left sternal edge f ollowing cardiac surgery usually results from combined right ventricular out \202 ow tract obstruction and pulmonary regurgitation. The mid-systolic click and systolic murmur of mit ral valve prolapse is best heard with the patient standing up. A continuous murmur arises f rom a patent ductus, systemic to pulmonary shunt, or arteriovenous \201 stulas. Box 8.4 Measure height, weight, blood pressure (both arms!), and oxygen satur- ation in all patient s. 12 lead ECG is essential at every visit. CHAPTER 8 Congenital heart disease 334 Electrocardiogram \200 Rate and rhythm: consider atrial \202 utter with variable block if constant rate of 120 o r 150/min \200\224this is easily confused with sinus rhythm. Atrial tachycardias are especi ally common after all forms of atrial surgery, e.g., intra-atrial repair for transposition of the great arteries. Look for signs of chamber enlargement \200\224atrial or ventricular hypertrophy. Assess for presence or absence of BBB. Measure duration of QRS in all postoper ative patients with tetralogy of Fallot: QRS duration >180 ms is associated with a higher r isk of arrhythmias, right heart dilatation, and late sudden death. If tachycardia is suspec ted, record 12 lead ECG during administration of IV adenosine or other diagnostic or therap eutic interventions. \200 Role of exercise testing \200 Assess heart rate and blood pressure (BP) response to exercise (blunted response in importa nt aortic valve stenosis). Compare upper and lower limb BP following coarctation repair. Mo nitor oxygen saturation by pulse oximetry to improve risk strati \201 cation in cyanosed p atients. Improves counseling and planning for pregnancy. Formal cardiopulmonary exercise te sting is reserved for deciding on retiming of surgical or catheter-based intervention. Can help distinguish limitation due to lack of aerobic \201 tness and assess maximal effort. May be useful to identify arrhythmias and chronotropic incompetence. \200 \200 Chest X-ray \200 \200 \200 Inexpensive, readily available, and invaluable investigation in CHD. Identify right \200 \223left orientation to assess cardiac and visceral positions. Assessment of the bronchial branching permits diagnosis of isomeric cardiac defects, e.g., symmetric morphological righ t bronchi characteristic of right atrial isomerism (usually associated with complex CHD \200\224common right atria, a common atrioventricular ori \201 ce, a great artery arising form one ventricular chamber, and total anomalous pulmonary venous connection). Identify si tus inversus (mirror-image anatomy with liver on the left and stomach bubble on the right w ith cardiac apex in right chest). Consider Kartagener syndrome. Discordance between positio n of the apex and visceral situs is usually associated with CHD. Record cardiothoracic rati o. Look for rib notching related to collateral blood supply in severe coarctation of the ao rta. Assess pulmonary vasculature (see Box 8.5). See Box 8.6 for use of other imaging modalities in assessing CHD. ASSESSMENT OF PATIENTS WITH CHD 335 Box 8.5 CXR assessment of pulmonary vasculature in patients with CHD Increased vascularity \200 \200 \200 Left-to-right shunt (ASD, VSD) Pulmonary edema Obstructed pulmonary venous drainage Decreased vascularity \200 Right ventricular out \202 ow obstruction, e.g., isolated severe pulmonary stenosis, follo wing tetralogy repair Pulmonary hypertension Unilateral increased pulmonary vascular markings \200 \200 \200 Consider ipsilateral systemic to pulmonary arterial shunt Overperfused major arterial pulmo nary collateral artery Obstructed pulmonary venous drainage, e.g., following Mustard or Sen ning intra-atrial repair for transposition of the great arteries Box 8.6 Imaging modalities in CHD Echocardiography \200 This is the most useful investigation in CHD, but only when directed by detailed history ta king and clinical examination. This should be performed by an experienced examiner with det ailed knowledge of all aspects of CHD. There is no substitute for sequential data, and a pr otocol for regular, standardized analysis is required. Imaging in adults may be limited by poor windows. Magnetic resonance imaging \200 MRI is ideal for assessment of extracardiac pulmonary arterial and venous trees. It provide s accurate quanti \201 cation of valvar regurgitation, e.g., assessment of pulmonary regur gitation and right ventricular function following repair of tetralogy of Fallot. Its utilit y is limited by the presence of implantable pacemakers and de \201 brillators and is gener ally only available at academic medical centers or centers equipped to treat CHD. Cardiac catheterization \200 This can aid in quantifying shunts and obtaining accurate hemodynamic data. It can facilita te percutaneous transcatheter procedures such as occlusion of atrial septal defects. With a n aging population, many patients with CHD need to undergo coronary angiography, as combine d surgical procedures may be required. CHAPTER 8 Congenital heart disease 336 Speci \201 c signs in patients with CHD Inspection Cyanosis or clubbing Oxygen saturation should always be measured by pulse oximetry. Central cyanosis is an indication of arterial desaturation and is noted when >5 g/ dL of reduced hemoglobin is circulating. Thus it is de pendent in part on the total hemoglobin concentration and may be missing in a patient with signi \201 cant desaturation but who is anemic. Differential cyanosis implies \202 ow of deoxygenated blood from the pulmonary trunk into the aorta distal to the left subclavian artery, e.g., non-restrictive patent ductus arteri osus with pulmonary vascular disease and right-to-left shunt. Previous operation scars Lift patient \200\231s arms and look for evidence of thoracotomy scars. Is the apex beat displa ced or even in the right chest? Assess comorbidity, e.g., scoliosis and respiratory dysfunc tion related to prior lateral thoracotomy. Jugular venous pulse This can give information a bout conduction defects and arrhythmias, waveform, and pressure. Increased resistance to at rial \201 lling results in an exaggerated a-wave, which may occur in isolated severe pulm onary steno- sis or in tricuspid atresia. Episodic \200\234cannon \200\235 waves occur in cases of heart block when the atrium contracts against a closed tricuspid valve. A prominent v-wave is characteristic of tricuspid regurgitation. Palpation \200 Feel all the pulses, including the femorals. Coarctation of the aorta is a clinical diagnos is. Check the blood pressure in upper and lower limbs, palpating the posterior tibial arter y with the cuff in \202 ated around the calf. Bounding pulses are characteristic of severe aortic regurgitation, patent ductus, or presence of a surgical systemic to pulmonary arter ial shunt (Blalock \200\223Taussig). An increase in right brachial pulse may re \202 ect t he Coanda effect of supravalvar stenosis in patients with Williams syndrome. Thrills may be felt in the femoral vessels, re \202 ecting arteriovenous malformation following prior ca rdiac catheterization. Check the position of the apex beat. Also, check that the liver and stomach are in the correct position. Situs inversus with the apex in the right chest is the mirror image of normal. 95% of patients with mirror- image dextrocardia have no coexisting congenital cardiac disease. Situs solitus with apex in the right chest is invariably assoc iated with CHD, often complex and unpredictable. A parasternal heave represents right ventr icular overactivity, which is most marked when there is both pressure and volume overload o f the chamber, such as following repair of tetralogy of Fallot. A palpable second sound in the upper left intercostal space is detected when pulmonary hypertension is present. SURGICAL OPERATIONS FOR CHD 337 Surgical operations for CHD Congenital heart disease surgery in adolescents and adults shou ld only be undertaken in specialist centers. There are three categories of patients: 1. Pat ients who have not undergone prior operations. 2. Patients who have undergone previous pall iative operations. 3. Patients who have undergone previous reparative procedures. Re-do ste rnotomy, preservation of myocardial performance, attention to pulmonary bed vascular abnorm alities, and aortopulmonary collaterals require careful prior planning and close cooperatio n among the surgeon, cardiac anesthesiologist, cardiologist, and intensive care team. Blalock \200\223Taussig shunt A systemic to pulmonary arterial shunt using a subclavian art erial conduit (Classical) or Gore-Tex tube (Modi \201 ed) is used to increase pulmonary blood \202 ow and improve oxygenation in cyanotic CHD. This is a palliative procedure tha t has superseded earlier operations such as the Waterston shunt (ascending aorta to right p ulmonary artery) or Pott \200\231s shunt (descend- ing aorta to left pulmonary artery). A c atheter-based approach is now frequently used. Coarctation of the aorta This is relieved by either a subclavian conduit approach or direct end-to- end anastomosis. Occasionally, a bypass graft is required in adult patients, from the ascending to descending aorta. Glenn shunt The superior vena cava is anastomosed to the ipsilateral pulmonary artery as a means of improving oxygenation in infants or young children. This procedure is usually con \201 ned to patients with \200\234single \200\235 ventricles and uni- ventricular circula tions. In its classical form, the right pulmonary artery was detached from the main pulmonary arte ry. The bidirectional Glenn shunt was fashioned such that blood from the superior vena cava entered both pulmonary arteries. Tetralogy of Fallot (Fig. 8.1) This condition requires closure of the ventricular septal de fect with a patch of pericardium or Goretex and relief of right ventricular out \202 ow tract obstruction by transannular patching, valvectomy, or placing a hom- ograft or conduit between the right ventricle and pulmonary artery. Rastelli operation This is usually undertaken in patients with complex CHD, e.g., transpos- ition of the great arteries with large ventricular septal defect. The VSD is closed by a l arge patch in such a way as to connect the left ventricle to the aorta, and a conduit or ho mograft connects the right ventricle to the pulmonary artery (see Fig. 8.2). CHAPTER 8 Congenital heart disease 338 RA Ao LA RA LA RV Figure 8.1 Tetralogy of Fallot. Rastelli repair Ao Ao PA PA LA LA Pulmonary stenosis VSD RA RA LV RV LV RV Patch across RV prevents blood passing from RV to aorta Conduit connects RV to PA Figure 8.2 Rastelli operation. Ao, aorta; LA, left atrium; LV, left ventricle; PA, pulmonar y artery; RA, right atrium; RV, right ventricle; VSD, venrtricular septal defect. Ross procedure This is an alternative to aortic valve replacement, which may be attrac- tiv e to younger patients, especially females. The diseased aortic valve is removed with the co ronary arteries detached. The patient \200\231s own pulmo- nary valve is resected and place d in the aortic position with the coronaries reattached. A homograft is placed between the right ventricle and the pulmonary artery. SURGICAL OPERATIONS FOR CHD 339 However, this procedure is currently out of favor with poor outcomes in long-term follow-up. Fontan operation This represents the de \201 nitive palliation for patients with effective ly uni- ventricular circulations such as mitral or tricuspid atresia. Blood from the superi or and inferior vena cavae is directed to the pulmonary arter- ies without the bene \201 t of a subpulmonary ventricle. Oxygenated blood returns to the systemic ventricle and is the n pumped to the aorta. Mustard and Senning operations These were life-saving innovations for treatment of patients with transpo- sition of the great arteries. They involved intra-atrial redirection of oxy- genated and deoxygenated blood to the systemic and pulmonary systems, respectively (see Fi g. 8.3). The right ventricle served as the systemic sub- aortic ventricle. They have been l argely abandoned because of late prob- lems with arrhythmias, pathway obstruction, and vent ricular failure. Arterial switch This has largely superseded the Mustard and Senning procedures. The aorta a nd pulmonary artery are relocated to their \200\234normal \200\235 positions with reanasto mosis of the coronary arteries to the neo-aorta. CHAPTER 8 Congenital heart disease 340 1 Aorta Art. pulm. V. cava V. pulm. 2 Aorta Art. pulm. V. cava V. pulm. 3 Aorta Art. pulm. LA V. cava V. pulm. Figure 8.3 Senning operation. This \201 gure was published in Annals of Thoracic Surgery, 77(6):2250 \200\2232258. Atrial switch operation: past, present, and future. Copyright Els evier 2004. PERCUTANEOUS TRANSCATHETER INTERVENTIONS FOR CHD 341 Percutaneous transcatheter interventions for CHD Balloon atrial septostomy This life-saving intervention is used in neonates with transposit ion of the great arteries. An atrial communication is created by tearing a hole in the atri al septum using a balloon catheter. This can be performed at the bed- side under echocardio graphic control or in the catheterization laboratory with both echocardiographic and angiog raphic guidance. Pulmonary valvuloplasty This is the procedure of choice for patients of all ages with pulmo nary valvar stenosis. It is less successful if the valve is dysplastic (Noonan \200\231s sy n- drome). The pulmonary valve annulus is measured by echocardiography or angiography and a balloon (100% \200\223120% diameter) is used. It is one of the most effective transcathete r interventions. Aortic valvuloplasty This intervention has limited use in adults. If the aortic valve is pl iable but not calci \201 ed, balloon dilatation may defer the need for de \201 nitive sur gery, but usually at the expense of aortic regurgitation. The balloon size should not excee d the size of the aorta at the site of the valve attachment. An anterograde approach via a trans-septal puncture is advised to reduce the incidence of valve damage. Atrial septal defect Most secundum atrial septal defects are amenable to percutaneous clo- sure. The Amplatzer septal occluding device is made of Nitinol (a nickel titanium alloy w ith inherent shape memory) and comprises two disks with a self-centering waist. The defect is balloon sized under transesophageal echocardiographic (TEE) guidance. Defects up to 40 m m in size can be closed providing there are suf \201 cient rims (>5 mm) to the pulmonary v eins and the attachment of the mitral valve. This is not suitable for any atrial defects other than those of the secun- dum variety, i.e ., sinus venosus defects or partial atrioventricular septal defects. Procedural complicatio ns are rare in expert hands. Antiplatelet agents are administered for 3 \200\2236 months un til the device has completely endothelialized. Transient headaches are common in the weeks following closure, but serious complications ar e rare. These include transient ischemic episodes or stroke, atrial arrhythmias, and emboli zation of the device. Concomitant electrophysiological procedures may need to be under- taken in patients with signi \201 cant atrial arrhythmias. Ventricular septal defects Indications for closing defects in adults are limited. Occasiona lly, small defects can produce volume overload of the left ventricle over time and require closure. Such defects may be amenable to transcatheter occlusion using the Amplatzer peri membranous or muscular occluding devices. CHAPTER 8 Congenital heart disease 342 This should only be undertaken in specialist centers. Complete heart block and device embol ization have been described. Coarctation of the aorta Surgical correction in the adult is a major challenge with its ass ociated risk of paraplegia. Both native and re-coarctation of the aorta can now be suc- ces sfully treated by transcatheter balloon dilatation and stenting. Covered stents may be requ ired for native coarctation to reduce the incidence of dissection and rupture. Remember tha t the aorta in these patients is espe- cially friable and that an aortopathy commonly coexi sts. MRI is invaluable in patient selection and for selecting stent size. This intervention shou ld only be undertaken in specialist centers where expert surgical help is readily available . Balloon dilatation of previous patch aor- toplasty carries the highest risk of aortic rup ture. Lifelong surveillance is necessary to detect aneurysm formation. Patent ductus arteriosus This may occasionally present in later life. If it is small or med ium sized with no pulmonary hypertension, it usually can be successfully occluded with a va riety of transcatheter occluding devices or coils. Pulmonary valve implantation Percutaneous transcatheter implantation of a bovine jugular ve nous valve mounted within a platinum-iridium stent into the right ventricular out- \202 o w tract is now possible. If it stands the test of time, this procedure will revolutionize o ur approach to management of patients with pulmonary regurgitation following right heart co ngenital surgery, offering a nonsurgi- cal approach. It may not be long before an implantable valve that can be used in the systemic circulation becomes widely available. SPECIFIC MANAGEMENT ISSUES 343 Speci \201 c management issues Complications of cyanotic CHD Chronic hypoxemia results in an increased red cell mass and total blood volume. This compensatory mechanism may initiall y enhance oxygen delivery; however, symptoms of hyperviscosity may develop. \200 Symptoms of hyperviscosity include headaches, visual disturbances (blurred or double vision ), impaired alertness, fatigue, parasthesia, tinnitus, myalgia, muscle weakness, and restle ss legs. Transient ischemic events or stroke may also occur. Measure hemoglobin and red cel l indices; most patients have a compensated erythropoesis with a stable hemoglobin. Therape utic phlebotomy should be reserved for symptomatic patients, e.g., with hemoglobin >20 g/dL or hematocrit >65%. Symptoms may be relieved by removal of 500 mL (maximum) of blood with concomitant \202 uid replacement of dextrose or saline. Phlebotomy should be performed no more than 2 times per year, as it increases the risk of stroke by causing iron de \201 ci ency. Intravenous line \201 lters should always be used. Iron de \201 ciency in a polycythemic patient should be treated with cautious iron supplem entation. Recheck hemoglobin 8 \200\22310 days later. Overaggressive treatment can result i n further increases in hematocrit. Skin Severe acne is common in cyanotic CHD. It can act as a source of infection and endocar ditis. Treat it aggressively. Gallstones These are common in cyanotic patients. Bilirubin is a product of hemo- globin br eakdown. Suspect them if a patient presents with severe abdomi- nal pain and discomfort. Renal function \200 \200 \200 Reduced glomerular \201 ltration rate Increased levels of creatinine Abnormalities in cle arance of uric acid frequently accompany chronic cyanosis and gout may result. Use contrast in angiography with caution and always prehydrate and premedicate the patient. Noncardiac surgery This should be undertaken in specialist centers and care delivered by a multidisciplinary team. Local anesthesia should be used, if possible; other- wise a cardiac anesthesiologist with experience in congenital heart disease should be consulted. Consider preoperative phlebotomy if hemoglobin >20 g/dL or hemat- ocrit >65%. Endocarditis prophylaxis and air line \201 lters should be employed. CHAPTER 8 Congenital heart disease 344 Pregnancy Box 8.7 The majority of women with CHD can tolerate pregnancy. Maternal congenital heart disease is now the major cause of maternal car- diac death in dev eloped countries. All patients need specialist counseling before embarking on pregnancy. Ca rdiologists are generally ill prepared to give such advice; pediatric cardiologists less so ! All young women of child-bearing age should undergo a detailed clini- cal and hemodynamic a ssessment that should include a formal exercise test and detailed echocardiography with emp hasis on systemic ventricular function. All women with complex CHD should be closely monitored in spe- cialist centers where delive ry should take place. Multidisciplinary input is essential. Pregnancy is contraindicated in some CHD patients (see Box 8.8). Attention to medications 1. Anticoagulation (warfarin embryopathy) must be balanced against the need for effective maternal anticoagulation in the setting of indications such as arrh ythmias or prosthetic valves. 2. ARBs and ACE inhibitors are contraindicated in pregnancy. 3. Assess the need for and cho ice of antiarrhythmic drug (e.g., chance for amiodarone-induced fetal thyroid dysfunction). Arrhythmia Arrhythmia is an important cause of morbidity and mortality and a major cause fo r hospitalization of CHD patients. It may lead to signi \201 cant hemo- dynamic deteriorat ion and is poorly tolerated. It may be due to the following: Underlying cardiac defect, e.g., atrial isomerism Part of n atural history, e.g., hemodynamic changes such as chamber enlargement or scarring Residual postoperative abnormalities \200 Box 8.8 Women with CHD in whom pregnancy is contraindicated \200 Pulmonary hypertension \200 E.g., Eisenmenger syndrome (50% maternal and fetal mortality; maternal death may occur up t o 2 weeks postpartum) \200 Heart failure secondary to failing Fontan circulation Women with severe cyanosis and polycy themia \200 If saturation is <80% at rest and hemoglobin is >18 g/dL, there is a greater incidence of m iscarriage and intrauterine growth retardation. SPECIFIC MANAGEMENT ISSUES 345 Management Specialist advice is essential. New presentation demands a complete hemodynamic reassessment including electrophysiological investigation. Correction of any underlying pos toperative hemodynamic abnormality may be one of the most important therapeutic interventio ns. \200 \200 Record a 12 lead ECG. Administer intravenous adenosine while recording the ECG. The mode of termination of the tachyarrhythmia may give very useful information on its etiology, e.g., pre-excitation. Urgent direct current cardioversion may be required if hemodynamic comprom ise is present. Ideally, transesophageal echocardiography should rule out intracardiac thro mbus. If the patient is on warfarin, always check the INR as well as the serum electrolytes prior to cardioversion. CHAPTER 8 Congenital heart disease 346 Atrial septal defect Atrial septal defect (ASD) is one of the most common lesions presentin g for the \201 rst time in adult life. It is often missed, as clinical signs of \201 xe d splitting of the second heart sound can be dif \201 cult to appreciate. It may present f or the \201 rst time with new-onset atrial \202 utter or \201 brillation. Consider the need for electrophysiological interventions, e.g., the Maze procedure for atri al \201 brillation. Shunting tends to increase with aging as the left ventricle stiffens. Closure is indicated in all symptomatic patients; few are truly asymptomatic when assessed by cardiopulmonary testing! There is no upper age limit. The vast majority of secundum def ects are amenable to transcatheter closure. Pulmonary hypertension needs to be excluded. Atrial arrhythmias are one of the common late medical problems. All other types such as sinus venosus defect (defect in upper atrial sept um associated with overriding of the superior vena cava and anomalous right pulmonary venou s drainage) and partial atrioventricular septal defect require surgical closure. A sinus ve nosus defect represents a major surgi- cal challenge involving redirection of anomalous pul monary vein(s). Risk of endocarditis is very low. Antibiotic prophylaxis is not indicated except for the 6 months post-repair with a prosthetic device or material. Ventricular septal defect The majority of cases are small, as larger defects are usually re paired in childhood. Eisenmenger syndrome (pulmonary vascular disease and hypertension associated with reverse, right-to-left shunting via intracardiac communi- cation \200\224VSD, ASD, PDA) is becoming increasingly rare. VSD should be closed if there is signi \201 cant shunt, previous endoca rditis, development of aortic regurgitation, or right ventricular out \202 ow tract obstru ction.