Cyanotic Congenital Heart Disease with Increased Pulmonary Blood Flow

PEDIATRIC CARDIOLOGY

~ ~~~~

0031-3955/99 $8.00 + .OO

CYANOTIC CONGENITAL HEART DISEASE WITH INCREASED

PULMONARY BLOOD FLOW Ronald G. Grifka, MD

Every day, pediatricians encounter cyanotic congenital heart disease (CHD) in children of all ages. With advances in the diagnosis and treatment of CHD, corrective procedures are performed at younger ages, often before the fetal cardiopulmonary physiology matures to the normal postnatal state. As neonates are discharged from the hospital very soon after birth, fewer in-hospital opportu- nities are available to evaluate the child for cyanotic (and acyanotic) CHD. This magnifies the importance of each physical examination before discharge, and at follow-up office examinations.

Several classifications have been developed to categorize cyanotic CHD. The four most commonly used classifications sort the defects by morphology and embryology, physiology, increased and decreased pulmonary blood flow, and the "five T's" (see later discussion). Although each classification has its merits (and devoted followers), no one system satisfies every physician's needs. From a pediatrician's perspective, physiology is a practical classification system because physiology is what is dealt with clinically.

In many children, the most difficult question to answer may be, "Is this child cyanotic?" Cyanosis is caused by deoxygenated blood in the capillary vessels. Central cyanosis is observed in the mucous membranes and extremities. In general, to detect central cyanosis requires 4 g or more of reduced hemoglobin; this corresponds to a systemic oxygen saturation of 80% to 85% (depending on the patient's hemoglobin level). If the systemic oxygen saturation is 85% or more, detecting cyanosis with the "eye oximeter " is very difficult. Isolated transient peripheral cyanosis (acrocyanosis) can occur in children with normal cardiac anatomy and function; it is not of cardiac etiology.

Causes for cyanosis in neonates and infants are numerous. The most com-

From Cardiac Catheterization Laboratories, Texas Children's Hospital; and Department of Pediatrics, Baylor College of Medicine, Houston, Texas

~ ~~

PEDIATRIC CLINICS OF NORTH AMERICA

VOLUME 46 NUMBER 2 * APRIL 1999 405

406 GRIFKA

mon cause of neonatal cyanosis is pulmonary dysfunction secondary to infection, meconium aspiration, respiratory distress syndrome, persistent fetal circulation, and extrinsic compression (e.g., pneumothorax or diaphragmatic hernia). Other causes of neonatal cyanosis include: asphyxia, shock, anatomic abnormalities (e.g., choanal atresia, tracheomalacia, cysts), hypoventilation (e.g., central or muscular) methemoglobinemia, and polycythemia.

At first glance, the title of this article seems to contradict itself. An obvious cardiac reason for cyanosis is decreased pulmonary blood flow (PBF), the subject of another article in this issue. So how can cyanosis occur in children who have increased PBF? First, a short review is included to standardize nomenclature for this article.

In patients who have normal cardiac anatomy, the deoxygenated ("blue") blood is pumped to the lungs (pulmonary arteries), while the oxygenated ("red") blood is pumped to the body (aorta). The effective pulmonary blood flow is the amount of deoxygenated blood that is pumped to the lungs; the lungs can work "effectively," oxygenating this blood. With normal cardiac anatomy, all of the blood pumped to the lungs is "effective" (deoxygenated). If oxygenated blood is pumped to the lungs, such as in a child with left-to-right shunting through a patent ductus arteriosus (PDA), this extra blood pumped to the lungs is already fully oxygenated, which is "ineffective" pulmonary blood flow; the lungs cannot further oxygenate this "red" blood. In children with cyanotic CHD, cyanosis occurs for two reasons: (1) blood flow (either blue or red blood) to the lungs is insufficient, or (2) a large percentage of the deoxygenated blood is pumped to the body (systemic circulation), and a large percentage of the oxygenated blood is pumped back to the lungs (together with some blue blood). The latter reason (2) is the subject of this article.

The old standby classification system of the five T's deserves mentioning. Five common cardiac causes of cyanosis begin with the letter T transposition of the great arteries, tetralogy of Fallot, truncus arteriosus, tricuspid atresia, and total anomalous pulmonary venous return. Although this list of five T's is not all encompassing (i.e., excluding pulmonary atresia and Ebstein anomaly), it is a helpful list to remember.

To conserve space, several abbreviations are used in this article. Most of these abbreviations are used frequently in clinical practice: ASD, atrial septal defect; CHD, congenital heart disease; PBF, pulmonary blood flow; PDA, patent ductus arteriosus; PFO, patent foramen ovale; PGE1, prostaglandin El; PVR, pulmonary vascular resistance; TAPVR, total anomalous pulmonary venous return; TGA, transposition of the great arteries; VSD, ventricular septal defect.

TRANSPOSITION OF THE GREAT ARTERIES

Transposition of the great arteries (TGA) is the most common cardiac cause of cyanosis in neonates, occurring in 5% of children with CHD.31 Although defining TGA seems like a simple task, some controversy exists. This article defines TGA as the aorta arising from the right ventricle (Figs 1 and 2). This is a simplistic but practical definition. Although this should imply that the main pulmonary artery arises from the left ventricle, this is not always true because of confounding factors (e.g., pulmonary atresia, double-outlet right ventricle, and I-malposition). A physiologic definition of TGA requires the oxygen saturation in the main pulmonary artery is greater than the oxygen saturation in the aorta. Another term for TGA is ventriculoarterial discordance.

CYANOTIC CONGENITAL HEART DISEASE WITH INCREASED BLOOD FLOW 407

U A

U B

Figure 1. A, Normal heart display, and B, a heart with transposition of the great arteries. A, Note the right ventricle (RV) is in continuity with the main pulmonary artery (MPA), while the left ventricle (LV) is in continuity with the aorta (Ao). In the heart with TGA, the RV is in continuity with the Ao, and the LV is in continuity with the MPA.

Figure 2. Transposition of the great arteries. Contrast injected into the right ventricle (RV) that gives rise to the anterior positioned aorta (AO). Also, contrast is flowing through the ventricular septa1 defect into the left ventricle (LV) and out the posterior positioned main pulmonary artery (MPA).

408 GNFKA

Embryology, Anatomy, and Physiology

During normal fetal development, the aortopulmonary septum separates the primitive truncus arteriosus and bulbis cordis into two vessels, the anterior main pulmonary artery, and the posterior aorta.1,2,14 If septation does not occur normally, TGA may occur. This results in an anterior and rightward aorta and a posterior and leftward main pulmonary artery. TGA is either d (dextro) or 1 (levo), the nuances of which are not discussed here, other than to say that 1-TGA is very complex and often associated with complicated CHD (e.g., ventricular inversion). Most children with transposition have d-TGA. When TGA occurs with no other CHD, it is referred to as "simple" transposition. TGA is one of several cardiac conotruncal abnormalities. Animal studies have shown that abnormalities of neural crest development can cause conotruncal abnormalities.%,

In children with TGA, other CHD can occur. A PDA is present at birth and needs to remain patent (to allow mixing of oxygenated and deoxygenated blood). A patent foramen ovale (PFO) or atrial septal defect (ASD) is present, allowing some mixing of blood. Another common finding is a ventricular septal defect (VSD), which also allows for mixing of blood. Valve and subvalve pulmonary stenosis can occur, usually coexisting with a VSD (Fig. 3).

With normal cardiac anatomy, the deoxygenated blood is pumped to the lungs (pulmonary circuit), where it becomes oxygenated. Then, the oxygenated blood is pumped to the aorta (systemic circuit). These two circuits work in series. With TGA, the right ventricle pumps the deoxygenated blood to the aorta, while the left ventricle pumps the oxygenated blood to the lungs. These are parallel circuits that are not compatible with life; the systemic organ systems do not receive sufficient oxygen, thus a progressively worsening acidosis occurs. Immediately postnatal, these infants are stable because of some mixing at the PDA (deoxygenated blood from aorta into the main pulmonary artery) and PFO

Figure 3. Complex form of TGA. There is a ventricular septal defect, along with valve and subvalve pulmonary stenosis.


(oxygenated blood from left atrium into the right atrium). In a short period of time (minutes to hours), the PDA constricts, mixing decreases, and cyanosis becomes obvious. If these children have an ASD or VSD, mixing continues and cyanosis is noted days or weeks later.

Postnatally, the pulmonary vascular resistance (PVR) falls. If PDA or VSD (which allows for mixing) is present, more blood flows from the systemic circuit into the pulmonary circuit. It is crucial for such a communication to exist; otherwise, the deoxygenated blood has limited access to the pulmonary vasculature to become oxygenated.

In nearly all patients, the left atrium pressure is higher than the right atrium pressure. Thus, if an ASD is present, shunting occurs predominantly from left to right (oxygenated blood from left atrium into the right atrium); a small amount of right-to-left shunting is present through the ASD. The ASD blood flow patterns are the same for children with TGA; the ASD provides a route for oxygenated blood to enter the systemic circulation (left atrium to right atrium to right ventricle to aorta).

In patients with simple TGA, cyanosis is noted soon after birth as the PDA begins to close (usually within several hours) because of inadequate mixing. To keep the PDA open, a prostaglandin El (PGE,) infusion can be lifesaving. Although the PDA provides for deoxygenated blood to flow into the pulmonary circuit, the PFO is the best route for oxygenated blood to enter the systemic circuit. Often, the PFO is restrictive, which limits the left-to-right shunting, resulting in increased left atrium pressure (which ”backs up” into the pulmonary veins and capillaries). An ASD is helpful and can be created by performing a balloon atrial septostomy procedure.46, 47 When an ASD is present (either congen- itally or created by a balloon atrial septostomy, sufficient bidirectional shunting occurs across the ASD to stabilize the child, eliminating the need for a PGE, infusion.

On occasion, cyanotic neonates with simple TGA respond poorly to PGE, infusion, and even after an ASD is created, significant cyanosis remains. Despite the ASD and PDA, these children are “poor mixers,” and additional observation or management is needed.3” On rare occasions, persistent pulmonary hypertension occurs simultaneously with TGA, which requires meticulous management (i.e., hyperventilation and alkalosis), methods not usually used when treating patients with cardiac cyanosis.

Some children have TGA and VSD. Usually, the VSD is moderate to large in size. Shunting is present across the VSD, predominantly right to left (right ventricle to left ventricle to pulmonary artery). Interestingly, these children have the same physiology as patients with VSD without TGA (i.e., pulmonary overcirculation), although they have systemic cyanosis because of the TGA. These children benefit from creating an ASD for left-to-right shunting.

If these children have TGA, VSD, and pulmonary stenosis, they may have an appropriate amount of shunting: balanced pulmonary and systemic blood flows affording stable hemodynamics and requiring no immediate treatment. The amount of pulmonary stenosis is variable, ranging from mild (which does not limit the PBF) to severe (which significantly limits PBF to cause severe cyanosis). Close follow-up is necessary.

TGA is not associated with any specific syndrome or chromosomal abnormality; however, several studies report a TGA male-to-female predominance of approximately 2:l.‘0,41 An increased incidence of TGA exists in infants of diabetic mothers.49

410 GRIFKA

Signs and Symptoms

Most neonates with d-TGA are of appropriate size for gestational age. As mentioned earlier, a male predominance exists. Neonates develop cyanosis soon after birth because of inadequate mixing; the nail beds and mucous membranes are the most obvious locations to detect cyanosis. With activity (e.g., crying or eating), cyanosis may become more intense. If an ASD, VSD, or PDA is present, mixing is improved, and cyanosis is detected later. Respirations are unlabored, unless a large VSD with increased PBF is present. The right ventricle (systemic ventricle) has systemic pressure, resulting in a right ventricle impulse at the left lower sternal border. The liver is not enlarged. Pulses are normal or slightly increased if a PDA is present.

In patients with TGA, the second heart sound (S2) is loud and single; it is loud because the anterior positioned aortic valve lies just under the sternum and single because the soft sound generated by pulmonary valve closure is diminished because of its posterior position. In most neonates with simple TGA, no murmur is present, or a soft, nonspecific systolic ejection murmur at the left midsternal border is present. If a VSD is present, as the PVR decreases, a holosystolic plateau murmur is noted at the left lower sternal border (right ventricle to left ventricle shunting); the smaller the VSD, the more prominent the murmur. Pulmonary stenosis results in a systolic ejection murmur at the left mid- to upper sternal border. Often, a PDA is present, but it does not cause a continuous murmur until the patient is several weeks to months of age.

Diagnostic Studies

When evaluating neonates with cyanosis, a chest radiograph is obtained. The cardiac silhouette is normal to minimally enlarged. The superior mediasti- num is narrow because of the anterior-posterior relationship of the aorta and the main pulmonary artery and the thymus is involuted (possibly a stress response); this causes an "egg on a string" appearance. The pulmonary vascular markings are increased. The aortic arch is left sided.

The ECG provides little specific information for TGA. The rhythm is sinus. If severe cyanosis or acidosis is present, sinus tachycardia occurs as an attempt to increase cardiac output. The QRS axis is rightward (between 90" and 160°), but this is the same for neonates with normal hearts. Right ventricular forces are prominent, but are the same as for normal neonates. If a child has complex TGA (i.e., VSD and pulmonary stenosis) and is not repaired surgically, as the child gets older, the right axis deviation and right ventricular hypertrophy become abnormal findings.

Echocardiography has become the standard diagnostic test.5 Two-dimensional imaging displays the pathognomonic findings: arising from the left ventricle, the posterior great artery bifurcates (which defines the main pulmonary artery and its branches) and arising from the right ventricle, the anterior vessel does not bifurcate but courses cephalad and gives rise to the arch vessels (which defines the aorta). It is important to determine whether valve or subvalve pulmonary stenosis is present; some "dynamic" subpulmonic stenosis is always present because of the high-pressure right ventricle bowing into the lower- pressure left ventricle. The atrial septum is interrogated for a PFO or ASD and the direction of shunting. Similarly, the ventricular septum is interrogated for a VSD and the direction of shunting. The aortic arch is studied to evaluate for a PDA and the direction of shunting. A coarctation of the aorta can occur, causing an unusual clinical finding, "reversed differential cyanosis"; the head and neck


are cyanotic because of deoxygenated blood supplied by the ascending aorta, whereas the lower body is pink because of oxygenated blood from the PDA into the descending aorta. Echocardiography is exceedingly helpful in determining whether the PDA responds to a prostaglandin infusion, and the creation of an ASD following balloon atrial septostomy. Defining the coronary artery anatomy may be helpful before surgical repair, although advances in surgical technique allow repair of nearly all coronary artery ~atterns.4~

Previously, cardiac catheterization was the gold standard for diagnosing critically ill neonates with cyanotic CHD (or ruling out CHD) and performing balloon atrial septostomy. With the advances in echocardiography and the use of prostaglandin infusions, diagnostic cardiac catheterization is often unneces- sary. If the coronary artery anatomy is undefined or seems unusual, a coronary angiogram may be needed for further definition. If additional CHD (e.g., VSD, pulmonary stenosis) is present that complicates the physiology or delays diagnosis, further hemodynamic evaluation may provide information needed for management.

For more than two decades, the balloon atrial septostomy procedure has been performed easily and safely in the cardiac catheterization laboratory using fluoroscopic guidance. Recently, the balloon atrial septostomy procedure has been performed with good results in the neonatal intensive care unit using echocardiographic guidance.56 Often, the umbilical vein is used to insert the balloon (providing the ductus venosus remains patent); otherwise, the femoral vein is used. The cardiac catheterization laboratory provides some advantages over the intensive care unit, including the ability to perform angiograms and ready access to emergency procedures if a severe problem arises."j

Treatment

The goal of treatment is to correct the flow of blood (the deoxygenated blood is pumped to the pulmonary arteries, the oxygenated blood is pumped to the body) and to provide an excellent long-term hemodynamic result. Treatment consists of three stages: (1) immediate medical diagnosis and stabilization, (2) surgery, and (3) follow-up evaluation and intervention (if needed).

Initially, these neonates are stabilized during evaluation and diagnosis. It is important to correct acidosis, hypercarbia, and hypovolemia that may have developed before diagnosis. If an adequate-sized ASD is not present, a PGE, infusion is needed to maintain PDA patency; the usual dose is 0.05 p,g/kg/min (range, 0.025-0.10 pg/kg/min). PGE, may cause apnea and low-grade fever; thus, cardiorespiratory monitoring is needed. A systemic oxygen saturation 60% or more is sufficient to provide adequate tissue oxygenation. If the prostaglandin infusion does not provide adequate mixing, a balloon atrial septostomy procedure can be performed. In some centers, a balloon atrial septostomy is performed on all children with simple TGA, intravenous or arterial lines are removed, these infants are allowed to eat, and surgery is performed within 7 to 14 days. In other centers, surgery is performed within 3 or 4 days of diagnosis, with or without performing a balloon atrial septostomy procedure. Each method has advantages.

For nearly 20 years, neonates had a balloon atrial septostomy procedure performed, they were followed intermittently in clinic for 8 to 12 months, then a surgical atrial switch operation (Mustard procedure) was performed. The Mustard procedure consists of suturing a baffle in the atrium, which directs the deoxygenated blood from the superior (SVC) and inferior (IVC) vena cavae to the mitral valve and left ventricle, where it is pumped to the pulmonary arteries. As the oxygenated blood returns from the pulmonary veins, it flows "over" the

412 GRIFKA

baffle to the tricuspid valve and right ventricle, where it is pumped to the body.43 The Mustard procedure had low initial morbidity and mortality rates and made deeply cyanotic children essentially "normal." A variant of the Mustard operation, the Senning operation, was devised and used all native atrial tissue instead of prosthetic baffle material3*; however, 8 to 15 years after the Mustard or Senning procedure, right ventricular failure, tricuspid regurgitation, arrhythmias, and sudden death developed in these 59, 61 These problems are caused by the right ventricle working for many years at systemic pressures pumping blood to the aorta; the right ventricle cannot maintain this workload.

The ideal operation would allow the left ventricle to pump the oxygenated blood to the aorta, and the right ventricle to pump the deoxygenated blood to the main pulmonary artery. With the failing long-term results of the Mustard operation and advances in coronary artery surgery, the Mustard operation was abandoned in favor of the arterial switch operation.32 Technically a more difficult operation, the arterial switch operation consists of transecting the aorta and main pulmonary artery, moving the main pulmonary artery anterior and anastomosing it to the right ventricle, moving the aorta posterior and anastomosing it to the left ventricle, then moving the coronary arteries from the anterior vessel (the "old aorta") to the posterior vessel (the "neoaorta"). Moving the aorta and main pulmonary artery is straightforward; moving the small coronary arteries, without kinking or stretching, is more challenging. After an initial learning curve, the results of the arterial switch operation are excellent, with a periopera- tive mortality rate of less than 5%.52, 57 Following successful arterial switch operation, the children need regular intermittent follow-up evaluations.

Stenosis can develop at the main pulmonary artery or aorta anastomosis and stenosis of the branch pulmonary arteries. Although only 10 to 12 years' follow-up are available with the arterial switch operation, the long-term results seem much better than for other operations. Time will tell whether any coronary artery problems occur as atherosclerosis develops during adult life.

If a neonate has TGA, VSD, and significant valve or subvalve pulmonary stenosis, an arterial switch operation cannot be performed because after the arterial switch operation, the pulmonary stenosis would become aortic stenosis. A balloon atrial septostomy should be performed, allowing the child to grow older and larger. The alternative surgical procedures are a Mustard operation or a Rastelli operation, which includes placing a conduit from the right ventricle to the main pulmonary artery and closing the VSD to the aorta.33

TRUNCUS ARTERIOSUS


Truncus arteriosus is an uncommon defect, occurring in 1% to 3% of patients with CHD.9, l2 Analogous to TGA, truncus arteriosus is a conotruncal cardiac abnormality. During septation of the fetal truncus arteriosus and bulbis cordis, incomplete formation of both great arteries is Only one great artery arises from the heart, giving origin to the coronary arteries, aorta, and pulmonary arteries. Only one semilunar valve forms, the truncal valve, which is dysplastic and may have from two to seven leaflets. The truncal valve is regurgitant in 50% of patients and stenotic in 33% of patients.39

Truncus arteriosus has been classified into four subtypes based on the origin of the pulmonary arteries." Type 1 has the main pulmonary artery arising from the posterior-leftward aorta, then bifurcating into the right pulmonary artery and left pulmonary artery (Fig. 4A). Type 2 has close but separate origins of the


C db D

Figure 4. Various forms of truncus arteriosus. A, Type I with a short MPA segment arising from the leftward, posterior aspect of the ascending aorta. B, Type II with separate origins of the RPA and LPA, arising close to each other on the posterior aspect of the ascending aorta. Note the left-sided aortic arch in A and B. C, Type 111 with separate origins of the RPA and LPA, arising far apart from the posterior-lateral aspect of the ascending aorta. 0, Type IV, which is more appropriately described as pulmonary atresia and VSD; there are separate origins of the RPA and LPA arising from the descending aorta. Note there is a right-sided aortic arch in C and D.

414 GRIFKA

right pulmonary artery and left pulmonary artery, arising from the posterior aorta (Fig. 4B). Type 3 has separate origins of the right pulmonary artery and left pulmonary artery, arising from the lateral sides of the aorta (Fig. 4C). Type 4 is a misnomer; multiple, small, collateral arteries arise from the descending aorta, and it is more appropriately described as pulmonary atresia (Fig. 40).

A large VSD (membranous to outlet region) is always present, resulting in equal right ventricular and left ventricular pressures. The right ventricle is enlarged and hypertrophied because of the pressure and volume load. The single great artery is enlarged because all of the aortic and pulmonic blood flow is ejected into it (Fig. 5). Because the aorta and pulmonary arteries arise from the single great artery, they have the same systolic pressure, which is markedly elevated for the pulmonary arteries. Occasionally, the origin of the right pulmonary artery or left pulmonary artery may be stenotic. The pulmonary arteries vary in size but usually are enlarged because of increased flow and pressure. A right aortic arch occurs in 33% of cases. An interrupted aortic arch (type B) occurs in 15% to 20% of cases. DiGeorge syndrome occurs in as many as 33% of patients; thus, chromosome analysis should be performed for 22qll deletion.61, 65

Because of the large VSD, mixing of oxygenated and deoxygenated blood occurs. Interestingly, streaming of blood occurs, such that the deoxygenated blood from the right ventricle flows predominately to the pulmonary arteries, and the oxygenated blood from the left ventricle flows predominately to the aorta. This accounts for only mild systemic cyanosis. Because the aorta and pulmonary arteries both arise from the truncus, both systolic and diastolic flow occur into the pulmonary arteries resulting in pulmonary overcirculation. As the PVR falls postnatally, the PBF increases even further, adding to the cardiac volume overload and enlargement. The increased PBF and pressure results in increased capillary fluid and interstitial edema.

If additional CHD is present, it can have a significant effect on the cardiovas-

Figure 5. Type I truncus arteriosus. The ascending aorta is enlarged and gives rise to the subclavian and carotid arteries. The short, main pulmonary artery arises from the leftward- posterior aspect of the truncus, and bifurcates into the right and left pulmonary arteries.


cular hemodynamics. The function of the truncal valve varies greatly. Truncal insufficiency results in an even larger volume load on the ventricles. Truncal stenosis adds a pressure load to the ventricles. If the truncal valve is insufficient and stenotic, the problems are compounded. When an interrupted aortic arch occurs, careful management is necessary, including a PGE, infusion to maintain the patency of the PDA; surgical aortic arch repair must be pursued within several days.

Signs and Symptoms

Usually, a murmur is heard within the first several days of life. Cyanosis is mild. As mentioned, the pulmonary arteries have increased flow, manifested clinically as tachypnea and diaphoresis, especially with feedings. As the PVR falls, these symptoms become more obvious. Pulses are bounding because of diastolic runoff into the pulmonary arteries. A right ventricular impulse is palpable at the left lower sternal border. The 52 should be single, but splitting has been reported. Truncal valve opening causes a midsystolic ejection click. A systoolic ejection murmur is audible along the left midsternal border due to the high-flow state. If truncal stenosis is present, the systolic ejection murmur is more pronounced. If truncal insufficiency is present, a diastolic decresendo murmur is noted. If stenosis is present at the origins of the branch pulmonary arteries, a continuous murmur may occur from flow into the pulmonary artery. If an interrupted aortic arch is present, decreased femoral pulses are detected as the PDA closes.

Diagnostic Studies

Arterial blood gases and pulse oximetry reveal mild cyanosis. A chest radiograph demonstrates cardiomegaly and increased PBF, which progress as the PVR decreases. Because of the high incidence of a right aortic arch with truncus arteriosus, the side of the aortic arch should be noted; a right aortic arch, systolic ejection click, increased pulmonary vascular markings, and mild cyanosis are suggestive of truncus arteriosus. ECG may be normal soon after birth, but after several days, biventricular hypertrophy is present.

As with TGA, echocardiography has become the standard diagnostic test.54 Two-dimensional imaging displays the large VSD, single great artery, dysplastic truncal valve, and the origin of the pulmonary artery(s) from the truncus. The coronary artery anatomy should be evaluated because this has importance on the surgical repair. In addition, the aortic arch must be evaluated for right- or left-sidedness, and the presence of a PDA or an interrupted arch. Doppler echocardiography determines whether the truncal valve is stenotic or regurgitant. Postoperatively, echocardiography is very useful to assess the truncal valve, ventricular function, residual VSD, and stenosis of the pulmonary arteries.

Often, cardiac catheterization is not needed for the initial diagnosis and management of truncus arteriosus. Catheterization and angiography can provide additional information if the pulmonary arteries are discontinuous or if the distal pulmonary vasculature is of concern. If the coronary artery anatomy is not well defined by echocardiography, angiography can accurately display the coronaries. If a child presents at several months of age or older, the PVR is elevated37; catheterization can measure the PVR and assess the pulmonary reac- tivity to various agents (e.g., oxygen or nitric oxide). Postoperatively, catheteriza-

416 GRIFKA

tion can be diagnostic and therapeutic (angioplasty for pulmonary artery stenosis).

Treatment

As the PVR decreases and PBF increases, diuretics and digoxin improve symptoms of pulmonary overcirculation; however, medical management is only a temporizing measure. The initial surgical procedure devised for truncus arteriosus was palliative; a pulmonary artery band was placed to limit PBF. Pulmo- nary artery band placement is a difficult procedure, usually providing inadequate regulation of PBF and distortion of the pulmonary arteries that complicates subsequent operations.

In the mid 1970s, improved management and operative techniques were developed that afforded better results for complete repair than did palliation.16 Nutrition is optimized to increase caloric intake. Diuretics and digoxin are used to control symptoms of pulmonary overcirculation. Angiotensin-converting enzyme inhibitors have been used to decrease the systemic resistance in hopes of decreasing PBF. At 6 to 8 weeks of age, when the PVR has decreased, definitive repair is performed, consisting of patch closure of the VSD and placement of a valved homograft from the right ventricle to the main pulmonary artery.15, 27 Type 1 truncus arteriosus is less complicated to repair because of the presence of a main pulmonary artery segment; types 2 and 3 are more complicated to repair because the right pulmonary artery and left pulmonary artery origins are separate. An incision is made in the right ventricle free wall for the homograft anastomosis; the coronary artery branches must be avoided, especially branches arising from the right coronary artery or an anomalous origin of the right coronary artery.

Postoperatively, these infants’ hemodynamics should be much improved, although diuretics and digoxin still may be needed. Follow-up evaluations are needed to assess the truncal valve for stenosis and insufficiency. With an excellent surgical result, these children grow and have a good level of activity; however, the homograft does not grow, resulting in gradually increasing right ventricular pressures. The homograft is replaced (with a larger homograft) when it becomes restrictive, usually after 3 to 6 years.z9 The second homograft should last these children into adolescence, when another replacement is needed. The homograft anastomosis to the pulmonary arteries can become stenotic. Balloon angioplasty, with or without stent implantation, can be therapeutic for patients with this stenosis, bearing in mind the homograft needs to be replaced at some point in the future. If the truncal valve is excessively regurgitant, it may need to be replaced with a homograft valve or a prosthetic valve.17

TOTAL ANOMALOUS PULMONARY VENOUS RETURN


Total anomalous pulmonary venous return (TAPVR) is an uncommon abnormality, occurring in 1% of patients with CHD.40 During cardiopulmonary embryogenesis, as the primitive lung buds develop, they are not connected to the heart. The left atrium grows posteriorly into the splanchnic (pulmonary venous) plexus, resulting in a connection between the left atrium and the pulmonary veins. If incomplete incorporation or malalignment of these structures occurs, the pulmonary veins do not connect to the left atrium; the pulmo-


nary veins drain into other embryologic venous structures-structures that usually involute if the pulmonary veins attach to the left atrium.

The two forms of anomalous pulmonary venous return are (1) total and (2) partial. Partial anomalous pulmonary venous return has some pulmonary veins draining normally to the left atrium and some ”anomalous” pulmonary vein(s) draining to other venous structures in the thorax. In patients with TAPVR, none of the pulmonary veins drain to the left atrium (Fig. 6). The four forms of TAPVR are (1) supracardiac, (2) cardiac, (3) infracardiac, and (4) mixed.I3 Type 1, or supracardiac, TAPVR (Fig. 7A) has the pulmonary veins coursing superiorly via a ”vertical vein” to the innominate vein, which drains into the superior vena cava. Type 2, or cardiac, TAPVR (Fig. 7 B ) has the pulmonary veins draining into the coronary sinus, which empties into the right atrium. Type 3, or infracardiac, TAPVR (Fig. 7C) has the pulmonary veins coursing inferiorly via a ”descending vein,” through the diaphragm; and into the portal venous system, which drains into the hepatic veins and inferior vena cava. Type 4, or mixed, TAPVR has various mixed pulmonary venous return; most commonly the left pulmonary veins draining to a vertical vein into the innominate vein, and the right pulmonary veins to the right atrium or coronary sinus (Fig. 70). With all forms of TAPVR, because all of the deoxygenated blood and all of the oxygenated blood returns to the right atrium, an ASD is necessary for any blood to reach the left atrium, left ventricle, and aorta.

For both supracardiac and cardiac TAPVR, if a large ASD is present, the physiology is similar to that of just an ASD. All of the venous blood returns to the right atrium, some crosses the ASD to the left heart, but most goes to the pulmonary arteries (just as an ASD, with more blood flowing to the pulmonary arteries than the aorta). Because mixing of the oxygenated and deoxygenated

Figure 6. Type 1 total anomalous pulmonary venous return. Contrast is injected into the pulmonary venous confluence displaying the right pulmonary veins (Fit Pulm V), which drain into the vertical vein. The vertical vein courses superiorly and enters the innominate vein (Innom V) that drains into the superior vena cava (SVC).

418 GRIFKA

A B

U

C

Figure 7. Four classifications of total anomalous pulmonary venous return. A, Type I; the four pulmonary veins drain into the vertical vein that enters the innominate vein. B, Type II; the pulmonary veins drain into the coronary sinus that enters the right atrium. C, Type Ill; the pulmonary veins join to form a descending vein that courses through the diaphragm and drains into the portal venous system. 0, Type IV, mixed pulmonary venous return; the two right pulmonary veins and the left lower pulmonary vein drain to the coronary sinus, while the left upper pulmonary vein drains into a vertical vein. Note that in all four, there is an atrial septa1 defect.

CYANOTIC CONGENITAL HEART DISEASE WlTH INCREASED BLOOD FLOW 419

blood occurs in the right atrium, the blood that crosses the ASD to the left heart is not fully oxygenated; thus, systemic cyanosis is noted on physical e~amination?~,

With infracardiac TAPVR, the pulmonary venous flow is obstructed at the hepatic connections and possibly at the diaphragm! This obstruction causes marked pulmonary venous congestion, difficulty with oxygenation, and cardiopulmonary instability. Often, these neonates have the same clinical presentation as those with persistent pulmonary hypertension; they may be initially diagnosed with pulmonary hypertension and treated with hyperventilation and alkalosis.

Because of the increased return of blood (both deoxygenated and oxygenated) to the right atrium, dilation of the right atrium, right ventricle, and pulmonary arteries occurs. The left heart structures are normal, although they are dwarfed by the enlarged right heart structures.

Signs and Symptoms

Neonates with supracardiac and cardiac TAPVR have mild to moderate cyanosis, depending on the amount of intracardiac mixing and the streaming of flow across the ASD. As the PVR decreases, the PBF increases even more, resulting in a larger left-to-right shunt. Tachypnea becomes more prominent, followed by diaphoresis with feeding. A right ventricular impulse occurs at the left sternal border because of the volume-overloaded right ventricle. The S2 is widely split, as is typical for a large ASD (which is an important finding because appreciation of wide S2 splitting is unusual in the neonatal period). The pulmonic component of the 52 is slightly increased. A systolic ejection murmur is present at the left mid- to upper sternal border caused by the increased PBF. A diastolic (tricuspid) rumble is appreciated at the left lower sternal border. The liver may be enlarged. Good peripheral perfusion is present, but cyanosis is noted.

Infradiaphragmatic TAPVR presents quite differently. These neonates feed poorly and become hemodynamically unstable. Respiratory distress develops, requiring intubation soon after birth. Systemic perfusion is compromised, requiring fluid boluses or inotropic support. A prominent right ventricular impulse is present at the left lower sternal border. Little murmur is appreciated, and the liver is enlarged.

Diagnostic Studies

The ECG, although not abnormal for neonates, demonstrates prominent right ventricular voltages with a rightward QRS axis; right atrial enlargement is present and is an abnormal finding. For supracardiac and cardiac TAPVR, chest radiographs reveal enlarged cardiac size with increased pulmonary vascular markings. Supracardiac TAPVR has a cardiac silhouette that resembles a figure eight or ”snowman” appearance caused by the dilated vertical vein and superior vena cava.6 Infradiaphragmatic TAPVR has a similar ECG, but the chest radiograph has impressive pulmonary venous congestion with “fluffy” lung fields that are occasionally difficult to differentiate from infiltrate or aspiration.

To diagnosis TAPVR, echocardiography has become the standard diagnostic modality.50, 55, 6o Echocardiography can be performed in any hospital area, from an active neonate in the clinic, to a critically ill child in the neonatal intensive

420 GRIFKA

care unit. For all types of TAPVR, the right atrium, right ventricle, and pulmonary arteries are markedly dilated. Because of the increased right ventricle volume, the ventricular septum is flattened and may have paradoxical systolic motion. An ASD (of various size) with right to left shunting must be present. The left atrium and left ventricle appear small relative to the dilated right heart structures. Determining the location and drainage of all four pulmonary veins is essential. A dilated pulmonary venous confluence may be present directly behind the left atrium, into which all four pulmonary veins enter. On the other end of the spectrum, each pulmonary vein may separately enter the vertical or descending vein. In addition to two-dimensional imaging, pulsed and color Doppler imaging is very helpful in determining the pulmonary venous anatomy.

Before echocardiography, cardiac catheterization was needed to rule out TAPVR in many neonates who were eventually diagnosed with persistent pulmonary hypertension or meconium aspiration; this was a risky diagnostic test in such ill neonates. With the advances in echocardiographic imaging, catheterization is rarely needed to diagnose TAPVR; however, on occasion, the pulmonary venous anatomy may be very complex, and because of the high PBF, an angiogram in each pulmonary lobe can provide needed anatomic information. If the ASD is restrictive, a balloon atrial septostomy can be performed.

Treatment

For both supracardiac and cardiac TAPVR with an unobstructed pulmonary venous confluence, if a large ASD is present, the physiology is similar to an ASD: pulmonary overcirculation, but with mild to moderate systemic cyanosis.18 Some institutions would perform surgical correction at the time of diagnosis. Obviously, surgical correction is necessary36, ”; however, if a child can be man- aged medically for several months, the surgical repair, postoperative course, and long-term results may be improved. Medical management includes digoxin and diuretics. If the ASD is restrictive, a balloon atrial septostomy is performed.

Infradiaphragmatic TAPVR requires prompt diagnosis and treatment. Be- cause of the obligatory pulmonary venous obstruction, surgical repair is performed soon after diagnosis. Postponing surgery provides no advantages. As surgery is being arranged, the neonate’s condition can be improved with careful management. Pulmonary edema is improved by positive pressure ventilation, including positive end-expiratory pressure. Supplemental oxygen may be needed, but physicians should attempt to use as little oxygen as possible, thus avoiding further vasodilation of the already overcirculated pulmonary vascular bed. Remember, these children are at least mildly cyanotic (because of mixing of the oxygenated and deoxygenated blood in the right atrium before it shunts across the ASD), so physicians should not aim for a systemic oxygen saturation more than 90%. If systemic output is compromised, small fluid boluses may be helpful in the acute management, but this will add to pulmonary edema in the longer term; packed red cells are the best fluid if the hemoglobin is not excessive.

The question of a PGE, infusion merits discussion. Before obtaining a thorough cardiac evaluation, if a neonate has suspected cardiac cyanosis, a PGE, infusion may be started. TAPVR is the only cyanotic CHD that could be affected negatively by a PGE, infusion because of additional PBF through the PDA; however, some right-to-left shunting may occur through the PDA that would increase the systemic blood flow. Also, prostaglandin may open or dilate the ductus venosus, which may partially decompress an obstructed infradiaphrag-


matic TAPVR.7 Thus, (in this author’s opinion) starting a PGE, infusion is reasonable as a cardiology evaluation or transport is arranged.

After surgical repair, these children need intermittent long-term follow-up. The dilated right heart structures do not return promptly to normal size; rather, they become somewhat smaller, then these children “grow into” the size of the right heart. The pulmonary venous anastomosis should be observed for possible stenosis as these children grow older and bigger.20,35,53 Also, the cardiac rhythm deserves reevaluation because the surgical cannulas and sutures may be placed near the sinus node and conduction system.51

Miscellaneous Defects

Various other complex CHD can cause systemic cyanosis with increased PBF. Hypoplastic left heart syndrome has excessive PBF as the entire cardiac output courses through the main pulmonary artery enroute to either the branch pulmonary arteries or PDA. Tricuspid atresia with a large VSD and no pulmonary stenosis can result in pulmonary overcirculation as the PVR decreases. The colligative term ”single ventricle” encompasses many CHDs, which vary from pulmonary atresia (with PDA dependency), to unrestricted PBF caused by a VSD or TGA. Lastly, neonates who initially had insufficient PBF and underwent placement of an aortopulmonary shunt may have excessive PBF through the shunt.

Pulmonary Vascular Obstructive Disease

Pulmonary hypertension is an ominous medical diagnosis. It can be a primary or secondary disorder. Often, pulmonary hypertension is defined as markedly elevated pulmonary artery pressures; however, a much more accurate (and correct) definition is an increased PVR. Although these two definitions are similar, the terms pulrnona y hypertension and increased PVR are used interchange- ably; this is incorrect. In children with CHD, when increased PVR becomes a chronic, irreversible condition, the condition is termed pulmona y vascular obstruc- five disease. To understand increased pulmonary vascular obstructive disease, we must first review Ohm’s Law as it applies to fluid dynamics:

Pressure = Flow X Resistance Elevated pulmonary artery pressure can be caused either by increased flow

(e.g., VSD or PDA), or increased PVR. If a child has a large VSD with a large left-to-right shunt, the pulmonary artery pressure is elevated because of increased PBF, but the PVR may be normal. Thus, this child may have pulmonary hypertension but not pulmonary vascular obstructive disease; if the VSD is closed, the pulmonary artery pressure should return to normal.

In patients with pulmonary vascular obstructive disease, the high pressure or flow causes pulmonary vascular changes in the small arterioles 0.1 mm to 1.0 mm in diameter. Smooth muscle hypertrophy is present in the media, and hypertrophy and fibrosis in the intima.z8 These changes are almost always reversible if the CHD is repaired, resulting in normalization of the pulmonary flow and pressure. If the CHD is not repaired, additional vascular changes occur that become irreversible, resulting in pulmonary vascular obstructive disease. Usually, the pulmonary vascular changes require at least 2 years to become irreversible, although longer and shorter periods have been reported. After

422 GRIFKA

irreversible pulmonary vascular changes occur (i.e., pulmonary vascular obstructive disease), the CHD should not be repaired because it is needed as a "pop- off" for the high-resistance pulmonary vasculature. For patients with pulmonary vascular obstructive disease, the only therapeutic options are chronic pulmonary vasodilator therapy with nifedipine, prostacyclin, or nitric oxide3, 48 or lung transplantation?', 44

SUMMARY

Pediatricians daily encounter children with systemic cyanosis. The numerous reasons for cyanosis in neonates and infants include pulmonary, hemato- logic, toxic, and cardiac causes. Congenital heart defects may cause cyanosis. Often, an obvious cardiac reason for cyanosis is decreased PBF; however, several congenital heart defects cause systemic cyanosis with increased PBF, such as TGA, truncus arteriosus, and TAPVR. Because neonates are discharged from the hospital soon after birth, this magnifies the importance of each physical examination. Pediatricians need to remain alert for children who have symptoms of increased PBF with or without cyanosis. With advances in the diagnosis and treatment of patients with CHD, corrective procedures can be performed at many ages.

References

1. Anderson RH, Wilkinson JL, Arnold R, et al: Morphogenesis of bulboventricular malformations: I. consideration of embryogenesis in the normal heart. Br Heart J 36:242, 1974

2. Anderson RH, Wilkinson JL, Arnold R, et a1 Morphogenesis of bulboventricular malformations: I. observations on malformed hearts. Br Heart J 36:948, 1974

3. Barst R, Rubin LJ, McGoon MD, et al: Long-term continuous prostacyclin treatment improves survival in primary pulmonary hypertension. J Am Coll Cardiol 21:368A, 1993

4. Baylen BG, Grzeszczak MB, Gleason ME, et al: Role of balloon atrial septostomy before early arterial switch repair of transposition of the great arteries. J Am Coll Cardiol 193025, 1992

5. Bierman FZ, Williams RG: Prospective diagnosis of d-transposition of the great arteries in neonates by subxyphoid two dimensional echocardiography. Circulation 60:1496, 1979

6. Bruwer A: Roentgenologic findings in TAPVC. Proc Staff Meet Mayo Clin 31:171,1956 7. Bullaboy CA, Johnson DH, Azar H, et al: Total anomalous pulmonary venous connec-

tion to portal system: A new therapeutic role for prostaglandin El? Pediatr Cardiol 5115, 1984

8. Burroughs IT, Edwards JE: Total anomalous pulmonary venous connection. Am Heart J 59:913, 1960

9. Calder L, Van Praagh R, Van Praagh S, et a1 Truncus arteriosus communis: Clinical, angiographic, and pathologic findings in 100 patients. Am Heart J 9223, 1976

10. Campbell M. Incidence of cardiac malformations at birth and later, and neonatal mortality. Br Heart J 35189, 1973

11. Collett RW, Edwards JE: Persistent truncus arteriosus: A classification according to anatomic types. Surg Clin North Am 29:1245, 1949

12. Crupi G, Macartney FJ, Anderson RH: Persistent truncus arteriosus: A study of 66 autopsy cases with special reference to definition and morphogenesis. Am J Cardiol 40:569, 1977

13. Darling RC, Rothney WB, Craig J M Total pulmonary venous drainage into the right


side of the heart Report of 17 autopsied cases not associated with other major associated cardiovascular anomalies. Lab Invest 6:44, 1997

14. De la Cruz MV, Arteaga M, Espino-vela J, et al: Complete transposition of the great arteries: Types of morphogenesis of ventriculoarterial discordance. Am Heart J 102271, 1981

15. DiDonato RM, Fyfe DA, Puga FJ, et al: Fifteen year experience with surgical repair of truncus arteriosus. J Thorac Cardovasc Surg 89:414, 1985

16. Ebert PA, Turley K, Stanger P, et al: Surgical treatment of truncus arteriosus in the first 6 months of life. Ann Surg 200:451, 1984

17. Elami A, Laks H, Pearl J M Truncal valve repair: initial experience with infants and children. Ann Thorac Surg 57:397, 1994

18. El Said, Mullins CE, McNamara DG: Management of total anomalous pulmonary venous return. Circulation 45:1240, 1972

19. Emmanouilides GC, Allen HD, Riemenschneider TA, et a1 (eds): Heart Disease in Infants, Children, and Adolescents, ed 5. Baltimore, Williams & Wilkins, 1995

20. Fleming WH, Clark EB, Dooley KJ, et a1 Late complications following surgical repair of total anomalous pulmonary venous return below the diaphragm. Ann Thorac Surg 27435, 1979

21. Frist WH, Carmichael LC, Joyd JE, et a1 Transplantation for pulmonary hypertension. Transplant Proc 25:1159, 1993

22. Fyler DC (ed): Nadas’ Pediatric Cardiology. Philadelphia, Hanley and Belfus, 1992 23. Garson A, Bricker JT, Fisher DJ, et a1 (eds): The Science and Practice of Pediatric

Cardiology, ed 2. Baltimore, Williams & Wilkins, 1998 24. Gathman JE, Nadas A S Total anomalous pulmonary venous connection: Clinical and

physiologic observations of 75 pediatric patients. Circulation 42143, 1970 25. Gelband H, Meter SV, Gersony WM: Truncal valve abnormalities in infants with

persistent truncus arteriosus: A clinicopathological study. Circulation 65:397, 1972 26. Graham TP, Atwood GF, Boucek RJ, et a1 Abnormalities of right ventricular function

following Mustard’s operation for transposition of the great arteries. Circulation 52678, 1975

27. Hanley FL, Heinemann MK, Jonas RA, et a1 Repair of truncus arteriosus in the neonate. J Thorac Cardovasc Surg 105:1047,1993

28. Heath D, Edwards JE: The pathology of hypertensive pulmonary vascular disease: A description of six grades of structural changes in the pulmonary arteries with special reference to congenital cardiac septa1 defects. Circulation 18:533, 1958

29. Heinemann MK, Hanley FL, Fenton KN, et al: Fate of small homograft conduits after early repair of humus arteriosus. Ann Thorac Surg 55:1409, 1993

30. Henry CG, Goldring D, Hartrnann AF, et al: Treatment of d-transposition of the great arteries: Management of hypoxemia after balloon atrial septostomy. Am J Cardiol 47299, 1981

31. Hoffman JIE, Christianson R Congenital heart disease in a cohort of 19,502 births with long-term follow-up. Am J Cardiol 42:641, 1978

32. Jatene AD, Fontes VF, Souza LCB, et al: Anatomic correction of transposition of the great arteries. J Thorac Cardiovasc Surg 83:20, 1982

33. Jonas RA, Freed MD, Mayer JE, et al: Long-term follow-up of patients with synthetic right heart conduits. Circulation 72 (suppl 2):77, 1985

34. Kirby ML: Cardiac morphology-recent research advances. Pediatr Res 21219, 1987 35. Lock JE, Bass JL, Castaneda-Zuniga W, et a1 Dilation angioplasty of congenital or

operative narrowings of venous channels. Circulation 70:457, 1984 36. Lupinetti FM, Kulik TJ, Beekman RH, et al: Correction of total anomalous pulmonary

venous connection in infancy. J Thorac Cardiovasc Surg 106:880, 1993 37. Mair DD, Ritter DG, Davis GD, et al: Selection of patients with truncus arteriosus for

surgical correction: Anatomic and hemodynamic considerations. Circulation 49:144, 1974

38. Marx GR, Hougen TJ, Norwood WI, et al: Transposition of the great arteries with intact ventricular septum: Results of Mustard and Senning operation in 123 consecutive patients. J Am Coll Cardiol 1:476, 1983

424 GRIFKA

39. McGoon DC: Truncus arteriosus and pulmonary atresia with ventricular septal defect. In Ravitch MM (ed): Pediatric Surgery, vol 1. Chicago, Year Book Medical, 1979

40. Mehriii A, Hirsch MS, Taussig HB, et al: Congenital heart disease in the neonatal period: Autopsy study of 170 cases. J Pediatr 65:721, 1964

41. Mitchell SC, Korones SB, Berendes Hw: Congenital heart disease in 56,109 births Incidence and natural history. Circulation 43323, 1965

42. Morse DE: Scanning electron microscopy of the developing septa in the chick heart. In Rosenquist GC, Bergsma D (eds): Morphogenesis and Malformation of the Cardio- vascular System (Birth defects: original article series, vol 14). New York, Allen R. Liss, 1978

43. Mustard WT: Successful two stage correction of transposition of the great vessels. Surgery 55469,1964

44. Parquin F, Cerrina J, Le Roy L, et al: Comparison of hemodynamic outcome of patients with pulmonary hypertension after double-lung or heart-lung transplantation. Transplant Proc 25:1157, 1993

45. Pasquini L, Sanders SP, Pamess IA, et al: Diagnosis of coronary artery anatomy by two-dimensional echocardiography in patients with transposition of the great arteries. Circulation 75:557, 1987

46. Neches WH, Mullins CE, McNamara DG: The infant with transposition of the great arteries: 11. Results of balloon atrial septostomy. Am Heart J 84:603, 1972

47. Rashkind WJ, Miller WW: Creation of an atrial septal defect without thoracotomy: A palliative approach to complete transposition of the great arteries. JAMA 19691, 1966

48. Rich S, Brundage BH High dose calcium channel-blocking therapy for primary pulmonary hypertension: Evidence for long-term reduction in pulmonary arterial pressure and regression of right ventricular hypertrophy. Circulation 76135, 1987

49. Rowland TW, Hubbell JP, Nadas AS Congenital heart disease in infants of diabetic mothers. J Pediatr 83:815, 1973

50. Sahn DJ, Allen HD, Lange LW, et a1 Cross sectional echocardiographic diagnosis of the sites of TAPVD. Circulation 60:1317, 1979

51. Saxena A, Fong LV, Lamb RK, et al: Cardiac arrhythmias following surgical correction of total anomalous pulmonary venous connection: Late follow-up. Pediatr Cardiol 12:89, 1991

52. Serraf A, Lacour-Gayet F, Bruniax J, et al: Anatomic correction of transposition of the great arteries in neonates. J Am Coll Cardiol 22:193, 1993

53. Shafers HJ, Luhmer I, Oelert T Pulmonary venous obstruction following repair of total anomalous pulmonary venous drainage. Ann Thorac Surg 43:432, 1979

54. Smallhom JF, Anderson RH, Macartney FJ: Two dimensional echocardiographic assessment of communications between ascending aorta and pulmonary trunk or individual pulmonary arteries. Br Heart J 47563, 1982

55. Smallhom JF, Sutherland GR, Tommasini G, et al: Assessment of TAPVC by two- dimensional echocardiography. Br Heart J 46:613, 1981

56. Steeg CN, Bierman FZ, Hordof AJ, et a1 "Bedside" balloon septostomy in infants with transposition of the great arteries: New concepts using two-dimensional echocardiographic techniques. J Pediatr 107944, 1985

57. Trussler GA, Castaneda AR, Rosenthal A, et al: Current results in management in transposition of the great arteries with special emphasis on patients with associated ventricular septal defect. J Am Coll Cardiol 10:1061, 1987

58. Turley K, Tucker WY, Ullyot DJ, et al: Total anomalous pulmonary venous connection in infancy: Influence of age and type of lesion. Am J Cardiol4592, 1980

59. Tynan M, Aberdeen E, Stark J: Tricuspid incompetance after the Mustard operation for transposition of the great arteries. Circulation 45-46:(suppl 1):3, 1972

60. Van Hare GF, Schmidt KG, Cassidy SC, et al: Color Doppler flow mapping in the ultrasound diagnosis of total anomalous pulmonary venous connection. J Am SOC Echocardiogr 1:341, 1988

61. Van Mierop LHS, Kutsche LM: Cardiovascular anomalies in DiGeorge syndrome and importance of neural crest as a possible pathogenetic factor. Am J Cardiol58133,1986

62. VanPraagh R, Van Praagh S The anatomy of common aorticopulmonary trunk (truncus arteriosus communis) and its embryological implications. Am J Cardiol 16:406, 1965


63. Ward KE, Mullins CE, Huhta JC, et al: Restrictive interatrial communication in total

64. Wames CA, Sommerville J: Transposition of the great arteries: Late result in adolescents

65. Wilson DI, Bum J, Scambler P, et al: DiGeorge syndrome: Part of CATCH 22. J Med

anomalous pulmonary venous connection. Am J Cardiol 571131, 1986

and adults after the Mustard procedure. Br Heart J 58:148, 1987

Genet 30:852, 1993

Address reprint requests to

Ronald G. Grifka, MD Texas Children’s Hospital

6621 Fannin Avenue Houston, TX 77030

Documents

Cyanotic Congenital Heart Disease with Increased Pulmonary Blood Flow