Pediatric Valvar Aortic Stenosis 

Updated: Jul 25, 2018
Author: Howard S Weber, MD, FSCAI; Chief Editor: Syamasundar Rao Patnana, MD 

Overview

Background

Aortic valve stenosis results from minor to severe degrees of aortic valve maldevelopment. This stenosis causes mild to severe obstruction of the left ventricular outflow that may be associated with other left heart obstructive lesions, varying degrees of left heart hypoplasia, or extracardiac malformations, including genetic disorders. This article focuses on the presentation, clinical features, and therapeutic options associated with aortic valve stenosis. 

An estimated 10%-15% of patients with aortic valve stenosis present with the condition when they are younger than 1 year due to severe stenosis. The remainder of patients may present later in childhood or in adulthood due to progressive obstruction. Adult patients with bicuspid aortic valves may develop significant stenosis or insufficiency after the valve becomes calcified (as seen in the image below), in the fourth, fifth, or sixth decade of life.

Valvular calcification of aortic stenosis is seen Valvular calcification of aortic stenosis is seen with cardiac fluoroscopy during catheterization.

Bicuspid aortic valves without stenosis or insufficiency in adult patients can be associated with progressive pathologic enlargement of the aortic root of uncertain etiology. This may require surgical root replacement once the aorta reaches a specific diameter.

In the neonate, transthoracic echocardiography provides complete diagnostic and hemodynamic information. In older patients, transthoracic echocardiography is usually diagnostic; in rare cases, however, a large adolescent patient may require transesophageal echocardiography to clearly delineate the left ventricular outflow tract and to detail the valve anatomy. Cardiac catheterization is usually performed in anticipation of balloon aortic valvuloplasty (see Workup).

Balloon aortic valvuloplasty is considered the initial treatment of choice in pediatric patients with congenital aortic valve stenosis. Surgical repair or replacement of an aortic valve is primarily reserved for patients in whom balloon valvuloplasty has failed with severe stenosis or have significant valve insufficiency in association with progressive left ventricular dilation or deterioration of left ventricular systolic function (see Treatment).

Go to Aortic Stenosis, Pediatric Supravalvar Aortic Stenosis, and Pediatric Subvalvar Aortic Stenosis for more complete information on these topics.

Anatomy

In patients with aortic valve stenosis, most commonly the valve is bicuspid with a single fused commissure and an eccentrically placed orifice. A third or rudimentary commissure may sometimes be apparent.

Less commonly, the valve is unicuspid and dome shaped, particularly in the neonate. Rarely, the valve has three unseparated cusps, with the stenosis being centrally located. Secondary calcification of the valve is extremely rare in childhood, and at times, the aortic valve anulus may also be underdeveloped or hypoplastic in association with mitral and left ventricular hypoplasia, adding to the severity of left ventricular outflow tract (LVOT) obstruction.

Pathophysiology

Pure aortic valve stenosis results in compensatory ventricular hypertrophy over time proportional to the degree of obstruction. Mild-to-moderate degrees of obstruction are usually well tolerated, with minimal hypertrophy and normal left ventricular function. As stenosis progresses, often in association with periods of rapid somatic growth, hypertrophy increases along with wall stress. With severe hypertrophy and valvar obstruction, myocardial ischemia may result from the combination of limited cardiac output, reduced coronary perfusion, and increased myocardial oxygen consumption. A small, fixed, cross-sectional area of the aortic valve can limit the ability to increase cardiac output with exercise. This may result in exercise-induced syncope or sudden death.

Severe obstruction in utero may lead to variable degrees of left-sided heart hypoplasia, endomyocardial fibroelastosis, reduced ventricular function, and significant mitral valve insufficiency.

Yetman et al described neonatal patients in whom rapid progression of aortic stenosis occurred within 6 months of diagnosis.[1] These patients often had well-preserved ventricular function but, during rapid growth, could exhibit fairly dramatic increases in the aortic valve gradient, requiring intervention. The typical absence of symptoms in this age group, does not correlate with the severity of aortic valve obstruction.

Spontaneous development of significant aortic insufficiency in the absence of stenosis is less common and may result in ventricular dilation. This could be associated with a recent episode of bacterial endocarditis. Rarely, left ventricular dysfunction and symptomatic congestive heart failure occur unless stenosis is reduced and/or insufficiency is relieved.

Etiology

Causes of aortic valve stenosis are multifactorial, although studies suggest a higher rate of recurrence of left ventricular outflow tract obstructive lesions in the offspring than other forms of congenital heart disease. The recurrence risk in offspring of an affected father is approximately 3% but is approximately 15% in offspring of an affected mother. Abnormal fetal hemodynamics are theorized to contribute to the development of aortic valve stenosis and other left-sided heart obstructive lesions.

Similarly, other forms of left heart obstructive disease may occur repeatedly within families (eg, hypoplastic left heart syndrome in a child whose older sibling had coarctation of the aorta). A definite genetic defect for aortic valve stenosis has not been identified, but the presence of a bicuspid aortic valve has been documented in multiple family members and is a common congenital heart defect in patients with Turner syndrome (monosomy X).

Epidemiology

The crude incidence of congenital heart defects is approximately 8 per 1000 live births. Aortic valve stenosis accounts for 3%-5% of all congenital heart defects. Authorities estimate a bicuspid aortic valve is present in as many as 1% of the general population, although accurate figures regarding prevalence of this abnormality are difficult to obtain, because many cases remain undetected and these valves function well for many decades.

Some studies have documented a higher prevalence of aortic valve stenosis in white children than in black and Hispanic children. There is a strong male sex predilection in aortic valve stenosis: the male-to-female ratio is 4:1.

Prognosis

The prognosis for patients with congenital aortic valve stenosis depends on the valve anatomy and its response to intervention. The severity of the disorder is widely varied, ranging from no symptoms in patients with a bicuspid aortic valve and no stenosis to critical illness in neonates.

Mortality is higher in patients presenting with severe or critical aortic valve stenosis during the first year of life, specifically in the neonatal period, although this risk has decreased significantly over the past 20 years. Mortality is in part influenced by associated congenital cardiac anomalies, which occur in as many as 20% of patients. These include coarctation of aorta, ventricular septal defect, mitral valve stenosis or insufficiency, and left ventricular hypoplasia. Undetected, severe aortic valve stenosis is a known cause of sudden death and accounts for approximately 1% of all causes of sudden death in young people.

A retrospective cohort study in 245 patients with congenital valvular aortic stenosis by Ten Harkel et al found that mortality was high for patients who were diagnosed in infancy but was almost absent in those who were diagnosed after infancy.[2] Interventions were required more often in children diagnosed at a younger age and/or with higher gradients.

Patient Education

Education is indicated for affected families regarding signs of progressive aortic stenosis, heart failure, and low cardiac output. Education regarding good dental care and avoidance of risk factors for endocarditis is imperative. 

Other goals of parent education include setting reasonable goals for exercise participation that allow for a healthy lifestyle but downplay long-term goals for competitive athletics or strenuous isometrics at a high level until significant relief of aortic valve disease is accomplished by aortic valve repair (balloon valvuloplasty versus surgical) or replacement.

Competitive aerobic sports are prohibited in patients with severe aortic valve stenosis, whereas patients with mild stenosis can participate if they have normal electrocardiogram findings, exercise tolerance, and no history of exercise induced chest pain, syncope, or tachyarrhythmias. Patients with moderate aortic valve stenosis may also participate in low-to-moderate dynamic competitive sports, if certain conditions are met.[3]

Similarly, emphasize that treatment for aortic valve disease is a lifelong process and is best introduced early and reinforced often to ensure that patients with aortic valve stenosis continue to receive ongoing follow-up care as they make the transition from an adolescent lifestyle at home to the independence of young adulthood.

 

Presentation

History

Neonates with critical stenosis are typically symptomatic and present with symptoms of congestive heart failure, including poor feeding, rapid breathing, poor urine output, and fussiness, as the ductus arteriosus closes within the first few days of life and systemic blood flow decreases.

Older children are usually asymptomatic and have a systolic murmur or systolic ejection click detected during sports physical evaluation or a preschool entrance examination.

Symptomatic children may report easy fatigability. A history of syncope or anginal-type chest pain related to exertion should prompt an immediate evaluation and intervention by a pediatric cardiologist. Most often, these patients have pure aortic valve stenosis, although occasionally a patient presents with predominantly aortic valve insufficiency and minimal stenosis.

Patients who underwent intervention as neonates and have stable palliated aortic valve stenosis, insufficiency, or both require monitoring through childhood. Progression of stenosis or insufficiency may not be readily evident by history, because exercise tolerance is often well preserved until valve dysfunction becomes severe. However, careful questioning about exercise tolerance, activity levels, avoidance of strenuous activities, and the presence of dyspnea, chest pain, presyncope, or excessive nap taking may reveal subtle signs of progressive aortic valve stenosis or insufficiency.

Adolescents diagnosed for the first time with aortic valve stenosis often have a bicuspid aortic valve with mild degrees of stenosis or insufficiency. Many of these patients remain free of symptoms or problems for many years unless valve deterioration progresses.

Symptoms

Symptoms will vary based on the age at presentation and the severity of obstruction. Rarely, aortic valve stenosis may lead to sudden death during exercise or can present later in life when the valve becomes calcified.

Neonatal aortic valve stenosis

Critical aortic valve stenosis presents as congestive heart failure in the first week of life. Once the ductus arteriosus begins to close, clinical signs of heart failure occur that mimic sepsis, and a cardiac murmur may not be detectable in the setting of low cardiac output. Significant mitral valve insufficiency may add to the congestive heart failure symptoms.

If the aortic stenosis is not critical, then neonates are usually asymptomatic but present with a systolic murmur, which leads to cardiology referral. Subsequent progression of aortic valve stenosis can widely vary in rapidity and severity.

Childhood aortic valve stenosis

Older children most often present with a systolic murmur as the first sign of aortic valve stenosis. As previously mentioned, these children are usually asymptomatic.

Physical Examination

Physical examination findings differ in neonates, children, and adolescents with aortic stenosis.

Neonatal aortic valve stenosis

Neonates who present with critical aortic stenosis and low cardiac output have reduced or absent pulses and poor peripheral perfusion. This contrasts with the differential pulses that are present in patients with critical coarctation of the aorta. They are tachycardiac and tachypneic, may have significantly increased work of breathing, and appear distressed.

A systolic murmur may be unimpressive because of low cardiac output secondary to left ventricular dysfunction. A precordial thrill is rare in the neonate. A click is often difficult to discern, because the degree of tachycardia and poor excursion of the valve may make the click less noticeable.

Severe aortic valve insufficiency is rare. However, if it is present, consider the diagnosis of an aortic–left ventricular tunnel.

Childhood aortic valve stenosis

A systolic ejection murmur is present at the left middle and the right upper sternal border. A thrill in the suprasternal notch is common even with modest levels of aortic valve stenosis and helps to localize pathology to the aortic valve. An ejection click is noted along the aortic axis and often is audible at the apex when it is not heard elsewhere. A precordial thrill is less common but, when present, is usually indicative of significant aortic valve stenosis.

The apical impulse may be normal or increased, secondary to left ventricular hypertrophy/dilatation. As with other semilunar valve pathologies, the severity of obstruction is proportional to the length and grade of the systolic murmur, assuming normal ventricular function and cardiac output.

A fourth heart sound, when present, usually indicates significant left ventricular hypertrophy.

The peripheral pulses may be normal or reduced, consistent with a narrow pulse pressure, depending on the degree of obstruction. Bounding pulses (water-hammer pulses) indicate significant aortic valve insufficiency.

Adolescent aortic valve stenosis

Aortic valve stenosis in adolescents is similar to that seen in children, although older patients are more likely to have aortic valve insufficiency. A systolic ejection click is common unless associated calcification of the aortic valve results in diminished valve excursion, which is unlikely in this age group.

Maneuvers to improve auscultation include having larger patients lean forward or assume the left lateral decubitus position. Having the patient squat may accentuate the murmur of aortic insufficiency.

 

DDx

Diagnostic Considerations

In neonates with heart failure, manifestations of severe aortic stenosis may resemble sepsis. Stenosis of the aortic valve itself must be differentiated from subaortic stenosis, supravalvular stenosis, or coarctation of the aorta.

Differential Diagnoses

 

Workup

Approach Considerations

In neonates within 24 hours after birth, pulse oximetry is routinely performed as a predischarge screening to rule out congenital heart disease and measured preductally (right arm) and postductally (lower extremity). Oxygen saturation may be lower in the legs (postductal circulation) because of right-to-left shunting at the level of the ductus arteriosus if patent.

The evaluation for sepsis in infants presenting with shock includes blood, urine, and cerebrospinal fluid (CSF) cultures.

Echocardiography is the diagnostic procedure of choice in all ages. In certain circumstances, exercise stress testing, cardiac catheterization, or both may be indicated.

Chest radiography may reveal cardiomegaly with pulmonary venous congestion, primarily in neonates who present with critical stenosis and symptoms of heart failure. Otherwise, this test is not helpful in asymptomatic patients although aortic root dilation may be identified.

Electrocardiography (ECG) is not especially useful in neonates or young children with significant aortic valve disease. In older patients, it may reveal left ventricular hypertrophy with or without a strain pattern.

Go to Imaging in Aortic Stenosis for more complete information on this topic.

Echocardiography

In the neonate, transthoracic echocardiography usually provides complete diagnostic and hemodynamic information. Essential considerations are the details of valve anatomy, anulus size, distribution of valve tissue, degree of left ventricular hypertrophy, and left ventricular systolic function. The presence or absence of associated lesions, such as mitral valve disease, coarctation of the aorta or subaortic stenosis, can also be well delineated.

Patients presenting with critical aortic valve obstruction and poor left ventricular systolic function may have echodense endocardium typical of endocardial fibroelastosis. Variable degrees of left ventricular hypoplasia or dilation may also be noted. These findings usually indicate that the severe obstruction was present for a significant amount of time prenatally.

In older patients, transthoracic echocardiography is usually diagnostic; in rare cases, however, a large adolescent patient may require transesophageal echocardiography to clearly delineate the left ventricular outflow tract and to detail the valve anatomy. Three-dimensional echocardiography may better delineate the aortic valve anatomy in hopes of determining whether balloon valvuloplasty versus surgical intervention would be more effective.

Doppler echocardiography is used to estimate the severity of aortic valve stenosis noninvasively. The peak instantaneous systolic gradient often overestimates the transvalvular peak-to-peak gradient obtained during cardiac catheterization. This appears to be related to the pressure recovery phenomenon. Mean Doppler gradients correlate better with peak to peak gradients measured during cardiac catheterization.

In neonatal critical aortic valve stenosis with poor left ventricular systolic function and low cardiac output, the Doppler-derived peak instantaneous gradient may be low and is therefore not indicative of the severity of obstruction.

In a retrospective study (1984-2012) comprising 360 pediatric patients with congenital valvar aortic stenosis reviewing the longitudinal assessment of the Doppler-estimated maximum gradient (DEMG) in this group pre- and post-balloon valvuloplasty, investigators found a statistically significant increase in DEMG over time.[4]  Post-balloon valvuloplasty, the rate of DEMG change was lower compared with the preprocedure values. The investigators indicated more frequent evaluations of DEMG progression should be made in these patients during periods of rapid somatic growth.[4]

Exercise stress testing and echocardiography

Exercise stress testing can usually be performed in children aged 6 years or older with aortic stenosis and may elicit symptoms that may not be evident by routine history. Resting Doppler gradients can be helpful in determining whether exercise restrictions are necessary[3] .

Exercise stress testing may also provide risk stratification if intervention is being contemplated. Factors such as heart rate, blood pressure response to exercise (blunted), exercise duration (reduced), provocable arrhythmias (ventricular ectopy of left ventricular origin) or electrocardiographic (ECG) ischemic changes, and measured oxygen consumption provide useful data on which to base decisions whether intervention is necessary.

Stress echocardiography is useful in delineating the response of the left ventricle to increasing afterload during exercise. The exercise stress test findings establish a baseline against which to compare subsequent study results, especially if the patient's symptoms change, the Doppler-derived gradient worsens or in the evaluation of the effectiveness following an intervention.

Cardiac Catheterization

Cardiac catheterization is usually performed in infants, children, and older adolescents with aortic stenosis in anticipation of balloon aortic valvuloplasty. Occasionally, the peak systolic gradient measured in the catheterization laboratory with the patient under conscious sedation is significantly less than that estimated by Doppler echocardiography, and this should be taken into consideration regarding whether intervention is indicated. It is an even greater problem when the procedure is performed under general anesthesia, used in some institutions

Other indications for catheterization may include the need to evaluate left ventricular filling pressures (impaired diastolic function secondary to left ventricular hypertrophy) and for accurate hemodynamic assessment in patients with multiple levels of obstruction, such as mitral stenosis or subaortic stenosis in combination with aortic valve stenosis. In the latter instance, high-fidelity catheters capable of discriminating between multiple levels of obstruction in close proximity are probably preferable but are significantly more difficult to use, especially in young patients.

Magnetic Resonance Imaging

Compared with echocardiography, magnetic resonance imaging (MRI) is rarely used to assess the details of aortic valve anatomy and is much more difficult to use in neonates, who have faster heart rates and more motion artifacts. Obtaining an MRI of infants and young children may require sedation, which carries risk of sudden death and, therefore, should be undertaken with close supervision and administered by an experienced anesthesiologist. New developments in gated MRI for assessing ventricular function may make MRI increasingly useful in adult patients.

Histologic Findings

In the presence of significant obstruction from aortic stenosis, the left ventricular myocardium hypertrophies concentrically. Critically ill neonates may have extensive endocardial fibroelastosis, especially in the presence of a dilated nonhypertrophied left ventricle. Patients with chronic aortic stenosis and significantly elevated left ventricular systolic pressure may exhibit fibrotic changes in the myocardium.

 

Treatment

Approach Considerations

The main goal is to preserve the native aortic valve and left ventricular function for as long as possible before aortic valve repair or replacement is necessary.

Neonates with critical aortic stenosis and low cardiac output require resuscitation and institution of prostaglandin E1 at a dose of 0.01-0.1 mcg/kg/min. Establishing patency of the ductus arteriosus can restore adequate systemic blood flow and the perfusion of vital organs.

Ongoing treatment in patients with aortic valve stenosis aims to preserve left ventricular function. If left ventricular dysfunction is detected in patients with significant aortic stenosis, medical therapy should be used only for stabilization; such patients are likely to benefit from interventions to reduce the degree of stenosis.

Patients with significant aortic valve insufficiency in combination with mild to moderate stenosis may be carefully treated with afterload reduction and/or diuretic therapy, although hypotension may occur. Patients with small aortic valve areas have a limited capacity for increased cardiac output with activity and may develop syncope or ischemic chest pain with exercise.

Inotropic drugs, such as dopamine, dobutamine, and epinephrine, may be indicated in cases of reduced cardiac output in the presence of decreased left ventricular systolic function. With critical aortic stenosis, avoid drugs that cause significant vasodilation, because they may cause significant hypotension. Patients with increased work of breathing and pulmonary edema benefit from intubation, positive pressure ventilation, and diuretic therapy.

Early reports of transcatheter balloon dilation in the 1980s were encouraging, although morbidity related to aortic valve insufficiency and femoral artery compromise were considered limitations of the procedure. With the advent of improved catheter technology, percutaneous balloon valvuloplasty has become an acceptable alternative to open heart surgery for severe congenital aortic valve stenosis and can be safely performed with virtually no mortality and with minimal morbidity.

Balloon aortic valvuloplasty appears to postpone the need for aortic valve surgery in children and adolescents and, therefore, should be the first option in the management of valvar aortic stenosis.[5]

Balloon Aortic Valvuloplasty

Balloon aortic valvuloplasty is a good initial treatment in most pediatric patients with aortic valve stenosis.[6] Patients with severely dysplastic valves may have a less favorable result, whereas surgical valve reconstruction might be more advantageous.

Achievement of this goal typically entails performing a conservative balloon valvuloplasty, reducing the peak-to-peak systolic gradient by 50%. Balloon diameters are usually 80%-100% of the aortic valve anulus dimension. In critically ill patients in whom the ductus arteriosus is not patent, surgical backup or circulatory support in the form of an extracorporeal membrane oxygenator (ECMO) should be available.

Neonates with critical aortic stenosis who are maintained on prostaglandin E1 should be sedated and intubated before the procedure is begun, to help maintain hemodynamic stability during the catheterization procedure. The overall goal, especially in neonates and infants, is to sufficiently relieve the aortic valve obstruction without development of significant valve insufficiency, thereby resulting in normalization of left ventricular systolic function.[7]

Catheter techniques

Several catheter techniques have been described over the past 20 years, with each having its own advantages and disadvantages. No consensus regarding which approach is optimal in the neonate with critical aortic valve stenosis has been reached. The techniques include retrograde catheterization via the femoral artery,[8, 9] the axillary artery,[10] the right subscapular artery,[11] the umbilical artery,[12] the right carotid artery,[13] and antegrade transfemoral venous[14, 15] or umbilical venous[16] catheterization through the atrial septum.

The advantages of a transvenous, axillary, subscapular artery, carotid artery, or umbilical or venous artery approaches include preservation of the femoral arteries for later intervention and reduced risk of femoral arterial occlusion, which may still occur despite the availability of very low profile 3 French (3F) balloon dilation catheters. However, crossing the aortic valve in neonates via the umbilical artery can be quite challenging.

The transvenous antegrade approach can also be difficult, especially in the presence of a small, hypertrophied left ventricle and mitral valve. This approach can result in injury to the mitral valve apparatus.

Crossing the aortic valve in a retrograde manner via the right carotid artery is technically easier, and it can be performed percutaneously or via a surgical cutdown with or without repair of the vessel. This particular procedure can be performed at the bedside with the aid of continuous transesophageal echocardiographic guidance, which offers the following advantages[17] :

  • Provides continuous hemodynamic assessment preintervention and postintervention

  • Avoids fluoroscopy exposure

  • Eliminates the need for repeated angiography to assess for aortic valve insufficiency

  • Eliminates the need to transport a sick neonate to and from the catheterization laboratory

In a retrospective study (2000-2014) comprising all Finnish children with isolated congenital valvar aortic stenosis treated with either balloon aortic valvuloplasty or surgical valvuloplasty, found that most of these children required more than one intervention during childhood.[18] However, there was a greater proportion of children who remained free from valve surgery after optimal balloon aortic valvuloplasty procedure.[18]

For further discussion of various transcatheter approaches in the neonate with severe/critical aortic stenosis, the reader is referred to other reviews.[19, 20]

Surgical Aortic Valvotomy

Although surgical aortic valvotomy (transventricular without cardiopulmonary bypass or open valvotomy with cardiopulmonary bypass) was once believed to carry an extremely high risk of morbidity and mortality, it is now considered to be relatively safe and effective.[21]

Occasionally, a significantly unstable neonatal patient who has a small aortic anulus or who requires attention to other associated lesions may be referred for surgical aortic valvotomy.

McCrindle et al reported that the early and intermediate results following either surgical valvotomy or catheter balloon valvuloplasty were similar, although the likelihood of important aortic valve insufficiency after balloon valvuloplasty and the likelihood of residual stenosis after surgical valvotomy are increased.[22]

Siddiqui et al reported that surgical valvuloplasty remains the best approach to treat neonates and infants with congenital aortic valve stenosis. After surgery, a higher proportion of patients remained free of reintervention than after interventional catheterization, and the relief of their stenosis lasted longer.[23]

Surgical Aortic Valve Replacement

The surgical replacement of an aortic valve is primarily reserved for patients in whom balloon valvuloplasty or surgical valvotomy has failed and in whom severe stenosis exists or significant aortic valve insufficiency has developed in association with left ventricular dilation or deterioration of left ventricular systolic function. The 3 options for aortic valve replacement are a mechanical prosthetic valve, a bioprosthetic valve, or the Ross procedure.

Mechanical prosthetic aortic valves are highly dependable and long lasting but require anticoagulation to prevent thromboembolic complications. Anticoagulation necessitates that the patient avoid collision sports and other activities that may result in significant bleeding. Warfarin adds significant complexity to the management of pregnancy, but the issues that arise are not insurmountable.

Delaying surgical valve replacement as long as possible to allow maximum growth of children without compromising ventricular function is an important goal of presurgical management. Such delay allows insertion of the largest possible prosthetic valve and reduces the need for repeat valve replacement solely because of patient growth.

Bioprosthetic aortic valve replacement includes various bioprosthetic materials (bovine pericardial, porcine, and cadaveric homografts) that do not last as long as mechanical prosthetic valves. Bioprosthetic valves may be used in patients with contraindications to mechanical valves, in women contemplating pregnancy in the near future, in patients who want to pursue collision sports or other activities with a high risk of trauma, and in patients who may be unable to receive or comply with anticoagulation therapy.

The Ross procedure (pulmonary autograft) or autotransplantation of a pulmonary valve to the aortic position is favored by surgeons because of the potential for growth of the pulmonary autograft valve through childhood. Such growth has been documented, as has adequate performance of a pulmonary valve in the aortic position. In addition, this procedure avoids the need for anticoagulation and serious sport restrictions, especially in active, injury-prone children.

Problems with this procedure in children include development of early stenosis or insufficiency of a pulmonary homograft placed in the pulmonary position. This can necessitate multiple interventional catheterizations or surgical reoperations during childhood to alleviate the obstruction or insufficiency of the homograft. The availability of catheter-based percutaneous pulmonary valve placement (Melody valve) should limit the need for multiple surgical conduit replacements. Significant enlargement of the neoaortic root, especially within the sinuses, may occur, and aortic insufficiency occasionally develops.

The choice of a mechanical valve, a bioprosthetic valve, or a Ross procedure should be reviewed at length for all patients, particularly when contemplating valve replacement.

Teratogenic effects of warfarin, management issues of anticoagulation during pregnancy, and need for reoperation, as well as durability of various valve options, should be reviewed at length.

Transcatheter aortic valve replacement (TAVR) has gained enthusiasm at many medical centers. The TAVR is reserved for calcific aortic stenosis of the elderly and aortic valve stenosis in children and adolescents should be addressed adequately by the less-invasive balloon valvuloplasty and surgical aortic valve replacement strategies discussed above.[24]

Activity

Activity limitations depend on the degree of severity of aortic valve stenosis and, in older children, the results noted on exercise stress testing. Strenuous isometric sports should be avoided; specific recommendations regarding sports participation have been published by the American Heart Association.[3]

Consultations

Consult a pediatric cardiologist, interventional pediatric cardiologist, and a pediatric cardiac surgeon, as needed.

Patients with dysmorphic features may require a genetic evaluation. Genetic counseling with regard to the risk of left ventricular outflow tract obstruction in the mother’s subsequent pregnancies also may be indicated. A neonatologist may be consulted to assist with management of critically ill neonates, especially those born prematurely.

 

Guidelines

Guidelines Summary

Aortic valvuloplasty

In 2011, the American Heart Association (AHA) released guidelines for interventions in pediatric cardiac disease that included the following class I recommended indications for aortic valvuloplasty in children[25] :

  • In newborns with isolated critical valvar aortic stenosis (AS) who are ductal dependent regardless of valve gradient
  • In children with isolated valvar AS who have the following characteristics:
    • Depressed left ventricular systolic function
    • ​Resting peak systolic valve gradient (by catheter) of ≥50 mm Hg
    • Resting peak systolic valve gradient (by catheter) of ≥40 mm Hg in the presence of anginal or syncopal symptoms or ischemic ST-T-wave changes on electrocardiography at rest or with exercise

According to these guidelines, aortic valvuloplasty may be considered in an asymptomatic child or adolescent with a resting peak systolic valve gradient (by catheter) of ≥40 mm Hg or without ST–T-wave changes if pregnancy or participation in strenuous competitive sports is desired (class IIb).

Aortic valve balloon dilation is not indicated in children with isolated valvar AS who also have a degree of aortic regurgitation that warrants surgical aortic valve replacement or repair (class III).

Transcatheter aortic valve replacement (TAVR)

In 2017, the AHA/American College of Cardiology released a focused update of their 2014 guidelines for managing patients with valvular heart disease, including their TAVR recommendations, which are summarized below.[26, 27]

Anticoagulation with a vitamin K antagonist (VKA) is indicated for patients with rheumatic mitral stenosis (MS) and atrial fibrillation (AF).

Anticoagulation is indicated in patients with AF and a CHA2DS2-VASc score of 2 or greater with native aortic valve disease, tricuspid valve disease, or mitral regurgitation (MR).

Surgical aortic valve replacement is recommended for symptomatic patients with severe AS (stage D) and asymptomatic patients with severe AS (stage C) who meet an indication for AVR when surgical risk is low or intermediate.

TAVR is recommended for symptomatic patients with severe AS (stage D) and a prohibitive risk for surgical AVR who have a predicted post-TAVR survival greater than 12 months.

Mitral valve surgery is recommended for symptomatic patients with chronic severe primary MR (stage D) and left ventricular ejection fraction (LVEF) greater than 30%.

Mitral valve surgery is recommended for asymptomatic patients with chronic severe primary MR and LV dysfunction (LVEF 30%-60% and/or LV end-systolic diameter [LVESD] ≥40 mm, stage C2).

Mitral valve repair is recommended in preference to mitral valve replacement (MVR) when surgical treatment is indicated for patients with chronic severe primary MR limited to the posterior leaflet.

A bioprosthesis is recommended in patients of any age for whom anticoagulant therapy is contraindicated, cannot be managed appropriately, or is not desired.

Anticoagulation with a VKA and international normalized ratio (INR) monitoring is recommended in patients with a mechanical prosthetic valve.

Anticoagulation with a VKA to achieve an INR of 2.5 is recommended for patients with a mechanical bileaflet or current-generation single-tilting disc AVR and no risk factors for thromboembolism.

Anticoagulation with a VKA is indicated to achieve an INR of 3.0 in patients with a mechanical AVR and additional risk factors for thromboembolic events (AF, previous thromboembolism, LV dysfunction, or hypercoagulable conditions) or an older-generation mechanical AVR (such as ball-in-cage).

Anticoagulation with a VKA is indicated to achieve an INR of 3.0 in patients with a mechanical MVR.

Aspirin 75-100 mg daily is recommended in addition to anticoagulation with a VKA in patients with a mechanical valve prosthesis.

Continuation of VKA anticoagulation with a therapeutic INR is recommended in patients with mechanical heart valves undergoing minor procedures (eg, dental extractions or cataract removal) where bleeding is easily controlled.

Temporary interruption of VKA anticoagulation, without bridging agents while the INR is subtherapeutic, is recommended in patients with a bileaflet mechanical AVR and no other risk factors for thrombosis who are undergoing invasive or surgical procedures.

Urgent evaluation with multimodality imaging is indicated in patients with suspected mechanical prosthetic valve thrombosis to assess valvular function, leaflet motion, and the presence and extent of thrombus.

Urgent initial treatment with either slow-infusion low-dose fibrinolytic therapy or emergency surgery is recommended for patients with a thrombosed left-sided mechanical prosthetic heart valve presenting with symptoms of valve obstruction.

Repeat valve replacement is indicated for severe symptomatic prosthetic valve stenosis.

Surgery is recommended for operable patients with mechanical heart valves with intractable hemolysis or heart failure (HF) due to severe prosthetic or paraprosthetic regurgitation.

Early surgery (during initial hospitalization before completion of a full therapeutic course of antibiotics) is indicated in patients with infective endocarditis (IE) who present with valve dysfunction resulting in symptoms of HF.

Early surgery (during initial hospitalization before completion of a full therapeutic course of antibiotics) is indicated in patients with IE who present with valve dysfunction resulting in symptoms of HF.

Early surgery is indicated in patients with left-sided IE caused by S aureus, fungal, or other highly resistant organisms.

Early surgery is indicated in patients with IE complicated by heart block, annular or aortic abscess, or destructive penetrating lesions.

Infective endocarditis prophylaxis

The 2011 AHA guidelines defined the following patient groups as at highest risk for adverse outcomes from IE[25] :

  • Those with prosthetic cardiac valves or prosthetic material used for cardiac valve repair
  • Those with previous IE
  • Those with unrepaired cyanotic congenital heart disease (CHD), including palliative shunts and conduits
  • Those with CHD and completely repaired congenital heart defect that was repaired with prosthetic material or device, regardless of placement by surgery or catheter intervention, during the first 6 months after the procedure
  • Those with repaired CHD who have residual defects at the site or adjacent to the site of a prosthetic patch or prosthetic device
  • Recipients of cardiac transplantation who develop cardiac valvulopathy

In a 2015 scientific statement updating its recommendations on IE in childhood, the AHA advocated for a shift in focus from antibiotic prophylaxis to an emphasis on oral hygiene and prevention of oral disease. However, the AHA recommends considering prophylactic antibiotic drugs before certain dental procedures for children in the highest-risk groups (class IIb), such as those discussed above.[28]

 

Medication

Medication Summary

Treatment with prostaglandin E1 is necessary for neonates with critical aortic stenosis and low cardiac output. This agent establishes patency of the ductus arteriosus and can restore adequate systemic blood flow and the perfusion of vital organs.

Prostaglandins

Class Summary

Prostaglandin E1 is used for the treatment of ductal-dependent, cyanotic congenital heart disease caused by decreased pulmonary blood flow. Patients with critical aortic stenosis and low cardiac output require resuscitation with prostaglandin E1. Establishing the patency of the ductus arteriosus can restore systemic blood flow and the perfusion of vital organs.

Alprostadil is a first-line palliative therapy to temporarily maintain patency of the ductus arteriosus before surgery. It produces vasodilation and increases cardiac output. Each 1 mL ampule contains 500 mcg/mL.

Alprostadil IV (Prostin VR Pediatric Injection)

This drug is effective in relaxing the smooth muscle of the ductus arteriosus. It is beneficial in infants with congenital defects that restrict pulmonary or systemic blood flow and who depend on a patent ductus arteriosus to get adequate oxygenation and lower body perfusion.

Inotropic Agents

Class Summary

Inotropic drugs, such as dopamine, dobutamine, and epinephrine, are indicated in cases of reduced cardiac output in aortic stenosis.

Dopamine

Dopamine is a naturally occurring endogenous catecholamine that stimulates beta1 and alpha1 adrenergic and dopaminergic receptors in a dose-dependent fashion; it stimulates the release of norepinephrine.

Dobutamine

Dobutamine produces vasodilation and increases the inotropic state. At higher dosages, it may cause an increased heart rate, exacerbating myocardial ischemia.

Epinephrine (Adrenalin)

Epinephrine has alpha-agonist effects that include increased peripheral vascular resistance, reversed peripheral vasodilatation, systemic hypotension, and vascular permeability. Beta2-agonist effects include bronchodilatation, chronotropic cardiac activity, and positive inotropic effects.

Loop Diuretics

Class Summary

Loop diuretics such as intravenous furosemide may be used carefully in pediatric patients with reduced cardiac function and/or significant mitral valve insufficiency when associated with severe aortic valve stenosis. The benefit is to reduce pulmonary venous congestion secondary to elevated left atrial pressures.

Furosemide (Lasix)

Furosemide is a loop diuretic that increases excretion of water by interfering with the chloride-binding cotransport system, which, in turn, inhibits sodium and chloride reabsorption in the ascending loop of Henle and distal renal tubule. It increases renal blood flow without increasing the filtration rate. It increases potassium, sodium, calcium, and magnesium excretion.