BONOW
ET AL., ACC/AHA TASK FORCE REPORT
JACC Vol. 32, No. 5, November 1998:1486-1588
ACC/AHA
Guidelines for the Management of Patients With Valvular
Heart Disease
VI.
Management of Valvular Heart Disease in Adolescents
and Young Adults
Although
the majority of valvular heart disease in older adults
is acquired, the predominant etiology is congenital
in children, adolescents, and young adults. It has been
estimated that the prevalence of congenital heart disease
is ~440,000 in the United States (exclusive of bicuspid
aortic valves; see below) (565).
Many patients with congenital heart disease have some
valvular involvement. Frequently, it is part of a more
complex congenital cardiac anomaly, ie, tricuspid stenosis
in children with pulmonary atresia and an intact ventricular
septum or AS from aortic valve atresia as part of a
hypoplastic left-heart syndrome. The management of these
complex diseases with multiple valve involvement is
beyond the scope of these guidelines. Rather, this section
concerns isolated valve involvement where it is the
primary anatomic abnormality.
In
evaluating valvular stenosis in children, the severity
of valvular obstruction is usually reported as peak-to-peak
systolic gradient at cardiac catheterization or maximum
instantaneous gradient by Doppler rather than valve
area. In the catheterization laboratory, the variation
in body size from the neonate to the adult, difficulties
in measuring cardiac output (especially in young children),
and the relatively rare patient with low cardiac output
have made peak ventricular-to-peak great-vessel pressure
gradients for semilunar valves and mean pressure gradients
for atrioventricular valves the reference standards.
With the development of Doppler echocardiographic assessment
of valvular obstruction, most pediatric cardiologists
have continued to rely on gradients calculated from
peak velocity using the formula gradient=4V2 for the
semilunar valves and mean gradients for the atrioventricular
valves rather than on valve area. The peak gradient
measured by Doppler velocity (based on maximum instantaneous
velocity) is higher than the peak-to-peak gradient measured
at catheterization. In contrast to children and adolescents,
valve area is used by many centers in evaluation of
the young adult.
Ventricular
end-systolic or end-diastolic diameter or volumes used
in evaluating patients with valvular regurgitation are
frequently corrected for the large variations in body
size among children, adolescents, and young adults.
Chamber size is corrected for body surface area (m2)
or commonly by the number of standard deviations (Z
score) above or below the mean with standard nomograms
that correct for body size (566).
The
management of the neonate, infant, and young child differs
significantly from that of the adolescent and young
adult. This section will deal exclusively with adolescents
and young adults.
A.
Aortic Stenosis
Although
most adults with aortic valve stenosis have a degenerative-calcific
process that produces immobilization of the valve cusps,
adolescents and young adults with isolated aortic valve
stenosis almost always have congenital fusion of one
or more commissures resulting in a bicuspid or unicuspid
valve. Although the prevalence of bicuspid and unicuspid
valves may be as high as 2%, only 1 of 50 children born
with these abnormalities will actually have significant
obstruction or regurgitation by adolescence.
Much
of what has been written in these guidelines for adults
with acquired AS may be transferred to the adolescent
or young adult. However, certain important differences
must be emphasized. Throughout childhood, the aortic
annulus and aortic valve must grow parallel with somatic
growth. If growth of either the annulus or valve leaflets
lags, increased obstruction may occur. Therefore, the
rate of progression during childhood and adolescent
growth may be different from that in the adult with
acquired heart disease. The report from the joint study
on the Natural History of Congenital Heart Defects (567)
followed 473 patients (before the advent of echocardiography),
60% of whom were initially evaluated between 2 and 11
years of age and 34% between 11 and 21 years of age.
One third of the children had an increase in the transaortic
gradient measured by cardiac catheterization during
the 4- to 8-year follow-up period. However, the 54 patients
>12 years of age showed very small increases. Those
with higher initial gradients had a greater likelihood
of demonstrating an increase in the gradient.
Recently,
long-term results of the original cohort have been reported
(568), with a mean
follow-up period of 20 years. Only 20% of those with
initial peak LV-to-peak aortic pressure gradients <25
mm Hg at initial catheterization had any intervention.
However, in those with an initial peak gradient >50
mm Hg, arrhythmias, sudden death, and other morbid events
(including endocarditis, congestive heart failure, syncope,
angina, myocardial infarction, stroke, and pacemaker
insertion) occurred at a rate of ~1.2% per year. Sudden
cardiac death occurred in 25 of the 370 patients followed
over ~8,000 patient years, an incidence of ~0.3% per
year. The severity of obstruction in those who died
could not be determined, and a higher-risk subgroup
could not be excluded.
The
diagnosis of AS can usually be made clinically, with
severity estimated by ECG and Doppler echocardiographic
studies. Diagnostic cardiac catheterization is occasionally
required if there is a discrepancy among clinical evaluation,
ECG, and/or Doppler echocardiographic findings. Exercise
testing may be useful, especially in those interested
in athletic participation.
Balloon
valvotomy for calcific AS in older adults has been at
best very short-term palliation. In contrast, the results
of balloon valvotomy in children and adolescents with
obstruction due to fusion of commissures have been considerably
more efficacious. In a large collaborative registry
involving 606 patients from 23 institutions, the peak
LV-to-peak aortic pressure gradients at catheterization
were reduced by a mean of 60% (569). In a single-institution
study of 148 patients dilated at age 1 month to 20 years
(570), midterm results showed an 8-year actuarial survival
of 95%, with 3 of the 4 deaths occurring in infants
who were dilated at <1 year of age. Seventy percent
of patients were free from operation and 50% were free
from intervention 8 years after dilation, which was
similar to results reported with surgical valvuloplasty.
Long-term follow-up is incomplete because balloon valvotomy
was introduced in the 1980s.
Although
balloon dilation has become standard in children and
adolescents with AS, it is rarely recommended in older
adults because even short-term palliation is uncommon.
There are insufficient published data to establish an
age cutoff. Until more information becomes available,
recommendations for balloon valvotomy should be limited
to adolescents and young adults in their early 20s,
although some older young adults without heavily calcified
valves may also benefit.
Because
balloon valvotomy has resulted in good long-term palliation
with little morbidity and little or no short- or intermediate-term
mortality in children, adolescents, and young adults
in their early 20s, the indications for intervention
are considerably more liberal than those in older adults
in whom intervention usually involves valve replacement.
Although data are not yet available, reducing the gradient
is likely to reduce the small incidence of sudden unexpected
death (usually while exercising) (571)
as well as the extent of interstitial myocardial fibrosis,
which has been observed in children and adolescents
who died and had evidence of repolarization abnormalities
on ECG.
Children
and young adults with Doppler gradients of 70 to 80
mm Hg or more (peak velocity >4.2 m/s), those who
develop LV repolarization or ischemic changes on the
ECG (T-wave inversion or ST depression) at rest or with
exercise, and those with symptoms may be considered
for cardiac catheterization and possible balloon dilation.
The gradient should be confirmed hemodynamically before
proceeding with dilation, and it is reasonable to perform
valvotomy in patients with catheterization gradients
>60 mm Hg. Patients with less severe gradients (50
to 70 mm Hg by Doppler echocardiography) who are interested
in participating in vigorous athletics or those contemplating
pregnancy are also commonly referred for balloon dilation.
Surgical valvotomy has now been replaced in most centers
by balloon valvotomy but is a reasonable alternative
if skilled interventional cardiologists are not available.
When
balloon aortic valvotomy is ineffective or significant
AR is present, valve replacement may be necessary. Because
bioprostheses have reduced durability in the young,
mechanical valves have been commonly used. The long-term
cumulative risks of endocarditis, thromboembolism, and
bleeding from anticoagulation over a 20- to 40-year
time frame have been problematic. Recently, the approach
of replacing the aortic valve with a pulmonary autograft
by means of a pulmonary or aortic homograft to replace
the native pulmonary valve, as first performed by Ross,
has gained acceptance in some centers (115,572-575).
Preliminary results indicate low surgical risk, with
the majority of autografts performing well for at least
a decade. This approach has the advantage of not requiring
anticoagulation, an important issue for active adolescents
and younger adults, including women contemplating pregnancy.
Recommendations
for Diagnostic Evaluation of the Adolescent or Young
Adult With Aortic Stenosis*
Recommendations
for Aortic Balloon Valvotomy in the Adolescent or Young
Adult (<;21) With Normal Cardiac Output*
B.
Aortic Regurgitation
AR
is an uncommon isolated congenital lesion, although
it may occasionally be found in adolescents and young
adults with a bicuspid aortic valve, discrete subaortic
obstruction, or prolapse of one aortic cusp into a ventricular
septal defect. It is commonly the consequence of attempts
to relieve stenosis of the valve by either balloon dilation
or surgical valvulotomy. The indications for surgery
with isolated AR or mixed aortic valve disease are at
present similar to adults, that is, symptoms, LV dysfunction
(ejection fraction <0.50), or very increased LV end-diastolic
or end-systolic diameter, taking into account variations
in body size. If the durability of pulmonary autograft
and homograft valves in the right ventricular outflow
tract is substantiated in long-term studies, the indications
for autograft valve replacement are likely to become
more liberal.
Recommendations
for Aortic Valve Surgery (Replacement With Mechanical
Valve, Homograft, or Pulmonary Autograft) in the Adolescent
or Young Adult With Chronic Aortic Regurgitation
C.
Mitral Regurgitation
Isolated
congenital MR is an extremely uncommon cardiac condition.
MR can be associated with MVP in adolescents or young
adults with connective tissue, metabolic, or storage
diseases. MR can be seen with acquired inflammatory
diseases such as rheumatic fever, endocarditis, or Kawasaki
disease or with certain collagen vascular disorders.
The
most common cause of MR in children is atrioventricular
septal defects. This is a defect caused by a deficiency
of the atrioventricular septum in the embryonic heart.
There may be an isolated ostium primum atrial septal
defect; ventricular septal defect in the inlet (posterior)
septum; abnormalities of the mitral or tricuspid valve,
including clefts; or some combination of the above.
In a complete atrioventricular septal defect, there
is a combination of a large primum atrial septal defect,
a large inlet (posterior) ventricular septal defect,
and a common atrioventricular valve that failed to develop
into separate mitral and tricuspid valves. Repair of
the defects in early childhood, with low mortality and
morbidity, is now possible. The most common long-term
sequela of surgery is MR, which may be mild, moderate,
or severe.
The
pathophysiology, diagnosis, and medical therapy of residual
MR in atrioventricular septal defects, rheumatic fever,
or MVP are similar to those discussed for the adult
with MR (section III.E.).
When associated with congestive heart failure or deteriorating
LV systolic function on echocardiography or angiography,
surgery should be performed. In children with atrioventricular
septal defects, MR can usually be reduced or eliminated
with surgery. In the postoperative atrioventricular
septal defect or MR secondary to MVP, rheumatic fever,
or inflammatory disease, it is frequently possible to
decrease the regurgitation with mitral annuloplasty.
Occasionally, MVR with a mechanical or biological valve
is necessary. When valve repair rather than replacement
is likely, surgery for severe MR may be contemplated
in the absence of heart failure or LV dysfunction.
Recommendations
for Mitral Valve Surgery in the Adolescent or Young
Adult With Congenital Mitral Regurgitation With Severe
MR
D.
Mitral Stenosis
In
developed countries, virtually all MS in adolescents
and young adults is congenital in origin. In developing
areas of the world, MS is more likely to result from
rheumatic fever. Congenital MS is usually classified
by the component of the mitral apparatus that is abnormal,
that is, the leaflets, annulus, chordae, or papillary
muscles. Frequently, multiple valve components are involved,
resulting in rolled, thickened leaflet margins; shortened
and thickened chordae tendineae; obliteration of the
interchordal spaces with abnormal chordal insertions;
papillary muscle hypoplasia; and fusion of the anterolateral
and posteromedial papillary muscles (576).
This latter condition causes the mitral apparatus to
appear like a funnel or a parachute. MS results from
the inability of blood to pass unobstructed from the
left atrium to the left ventricle through a very abnormal
mitral apparatus.
Congenital
MS may be associated with a wide variety of other congenital
cardiac malformations of the left side of the heart,
including coarctation of the aorta.
The
clinical, electrocardiographic, and radiologic features
of congenital MS are similar to acquired MS in adults.
The echocardiogram is beneficial in evaluating the mitral
valve apparatus and papillary muscles and may provide
considerable insight into the feasibility of successful
valve repair. The information obtained from transthoracic
imaging is usually sufficient, but in older children,
adolescents, and young adults, a transesophageal echocardiogram
is sometimes necessary.
Medical
management is of limited utility in these patients,
but it is important to prevent and treat common complications
such as pulmonary infections, endocarditis, and atrial
fibrillation. Surgical intervention may be necessary
in severe cases.
The
surgical management of congenital MS has improved considerably
with the improved appreciation of the mechanism of mitral
valve function and the improved ability to visualize
the valve afforded by transesophageal echocardiography.
In those with a parachute mitral valve, creation of
fenestrations among the fused chordae may increase effective
orifice area and improve symptoms dramatically. MVR
may occasionally be necessary but is especially problematic
in those with a hypoplastic mitral annulus in whom an
annulus-enlarging operation may be necessary. Recently,
balloon dilation of congenital MS has been attempted
(577), but its utility
is unproved. This is one of the most difficult and dangerous
therapeutic catheterization procedures and should be
undertaken only in centers with operators who have established
experience and skill in this interventional procedure.
Recommendations
for Mitral Valve Surgery in the Adolescent or Young
Adult With Congenital Mitral Stenosis
E.
Tricuspid Valve Disease
Acquired
disease of the tricuspid valve is very uncommon in adolescents
and young adults. Other than occasional cases of TR
secondary to trauma, bacterial endocarditis in intravenous
drug abusers, and small ventricular septal defects in
children in whom the jet through the ventricular septum
creates endothelial damage to the tricuspid valve, virtually
all cases of acquired TR are limited to case reports.
Most
cases of tricuspid valve disease are congenital, with
Ebstein's anomaly of the tricuspid valve being the most
common. In Ebstein's anomaly, there is inferior displacement
of the septal and posterior leaflets of the valve into
the right ventricle. If there is significant adherence
of the leaflets to the right ventricular wall, the normal
or relatively normal anterior leaflet fails to coapt
with the abnormal posterior leaflet, creating severe
TR. If the valve leaflets are not adherent, there is
redundancy of valve tissue with severe prolapse associated
with varying degrees of TR.
There
is variation in the severity of valve leaflet abnormalities.
Some children may have severe TR, especially in the
perinatal period, when pulmonary vascular resistance
and resulting right ventricular pressures are high.
Others have very mild abnormalities that may not be
recognized until a chest x-ray obtained for other reasons
shows cardiomegaly. An interatrial communication, usually
in the form of a patent foramen ovale, is present in
most cases. If TR elevates right atrial pressure above
left atrial pressure, right-to-left shunting can occur,
with resulting hypoxemia. One or more accessory conduction
pathways are quite common, with a risk of paroxysmal
atrial tachycardia of ~25%.
Patients
with Ebstein's anomaly may be asymptomatic with no cyanosis
and no atrial arrhythmias. More commonly, they are cyanotic
due to right-to-left shunting, which is associated with
exercise intolerance. Right ventricular dysfunction
may eventually lead to right-sided congestive heart
failure frequently exacerbated by an atrial arrhythmia
such as atrial tachycardia, atrial flutter, or atrial
fibrillation.
The
natural history of Ebstein's anomaly varies. In patients
who present in the perinatal period, the 10-year actuarial
survival is 61% (578).
In a study that included more children who presented
after the perinatal period, the probability of survival
was 50% at 47 years of age (579).
Predictors of poor outcome were NYHA functional Class
III or IV symptoms, cardiothoracic ratio >65%, or
atrial fibrillation. However, patients with Ebstein's
anomaly who reach late adolescence and adulthood often
have an excellent outcome (579).
Surgical
management of Ebstein's anomaly remains challenging.
For older children, adolescents, and young adults, tricuspid
valve repair has been attempted. Reconstruction of the
valve is occasionally possible, especially when there
is a mobile anterior leaflet free of tethering to the
ventricular septum. Valvuloplasty may be performed with
positioning of the displaced leaflet of the tricuspid
valve to the normal level, sometimes with placation
of the atrialized portion of the right ventricle to
reduce its size.
Occasionally,
the tricuspid valve is not reparable, and valve replacement
with a bioprosthesis or a mechanical valve may be necessary.
When present, atrial communications should be closed.
If an accessory pathway is present, this should be mapped
and obliterated either preoperatively in the electrophysiology
laboratory or at the time of surgery.
Recommendations
for Diagnostic Evaluation* of Ebstein's Anomaly of the
Tricuspid Valve in the Adolescent or Young Adult
Recommendations
for Surgery in the Adolescent or Young Adult With Ebstein's
Anomaly With Severe Tricuspid Regurgitation
F.
Pulmonic Stenosis
1.
Pathophysiology. Because the pulmonary valve is
the least likely valve to be affected by acquired heart
disease, virtually all cases of pulmonary valve stenosis
are congenital in origin. Most patients with stenosis
have a conical or dome-shaped pulmonary valve formed
by fusion of the valve leaflets, which project superiorly
into the main pulmonary artery. Occasionally, the valve
may be thickened and dysplastic, with the stenosis caused
by inability of the valve leaflets to move sufficiently
during ventricular systole (580).
Symptoms
are unusual in children or adolescents with pulmonary
valve stenosis even when severe. Adults with long-standing
severe obstruction may have dyspnea and fatigue secondary
to an inability to increase cardiac output adequately
with exercise. Exertional syncope or light-headedness
may rarely be seen, but sudden death is very unusual.
Eventually, in the neonate or adult with long-standing
untreated severe obstruction, TR and right ventricular
failure may occur.
At
any age, if the foramen ovale is patent, right ventricular
compliance may be reduced sufficiently to elevate right
atrial pressure, allowing right-to-left shunting and
cyanosis. This increases the risk of paradoxical emboli.
2.
Diagnosis. The clinical diagnosis of pulmonary valve
stenosis is straightforward, and the severity can usually
be determined accurately by 2-D and Doppler echocardiography
(see below). Diagnostic catheterization is rarely required.
Recommendations
for Initial Diagnostic Workup of Pulmonic Stenosis
3.
Clinical Course. The clinical course of children
and young adults with pulmonary valve stenosis has been
well described. The Natural History of Congenital Heart
Defects study (581) in the mid 1960s and early 1970s
followed 564 patients with valvular pulmonary stenosis
with cardiac catheterization at 4- and 8-year intervals.
On admission to the study, ~15% were <2 years old;
20%, 12 to 21 years old; and the remainder, 2 to 11
years old. At initial cardiac catheterization, they
were divided into 4 groups based on severity:<25
mm Hg peak-to-peak gradient between the right ventricle
and the pulmonary artery, trivial; 25 to 49 mm Hg, mild;
50 to 79 mm Hg, moderate; and >80 mm Hg, severe.
Of
the 261 patients (46% of the total) treated medically,
most had trivial, mild, or moderate obstruction. None
of these patients had cyanosis or congestive heart failure,
and only 6% had symptoms. There were no deaths during
the study. The pressure gradients were stable in the
majority, with 14% of patients manifesting a significant
increase and 14% a significant decrease. Most of the
increases were in children <2 years old and/or those
with initial gradients >40 mm Hg. Those not in either
category had only a 4% chance of an increase in the
gradient >20 mm Hg. There was little or no change
in the overall status of the medically treated patients.
During the period of observation, 304 patients, most
with moderate or severe disease, were treated surgically.
Only 1 death occurred among the 245 patients in this
group who underwent surgery beyond infancy. At postoperative
follow-up, the gradient had been reduced to insignificant
levels in >90%, with no recurrence of pulmonary stenosis
in those followed up to 14 years.
In
1993, the second Natural History of Congenital Heart
Defects study (582)
reported on a 16- to 29-year (mean, 22 years) follow-up
of the same group of patients. The probability of 25-year
survival was 96%, not statistically different from the
normal control group. Less than 20% of patients managed
medically during the first Natural History Study subsequently
required a valvotomy, and only 4% of the operated patients
required a second operation. Most patients, whether
managed medically or surgically, had mild obstruction
by Doppler echocardiography. For patients who had an
initial transpulmonary gradient <25 mm Hg in the
first Natural History Study, 96% were free of cardiac
operation over a 25-year period.
Infective
endocarditis was uncommon. Only 1 case developed in
the 592 patients followed a median of 18 years, an incidence
of 0.94 per 10,000 patient years. Although endocarditis
prophylaxis has been recommended for patients with PS,
the incidence and severity of infection are such that
the morbidity from anaphylactic reactions to endocarditis
prophylaxis may be as problematic as the disease itself.
Surgical
relief of severe obstruction by valvotomy with a transventricular
(583) or transpulmonary
(584) artery approach
predates the introduction of cardiopulmonary bypass.
A nonsurgical approach with balloon valvotomy was described
in 1982 (585) and by
the late 1980s had become the procedure of choice for
the typically domed, thickened valve virtually everywhere
in the United States, both for children (586)
and adults (587,588).
Surgery is still required for the dysplastic valve often
seen in Noonan's syndrome. Although long-term follow-up
of pulmonary balloon valvotomy is not yet available,
the early and midterm results (up to 10 years) (589)
suggest results similar to surgical valvotomy, that
is, little or no recurrence over a 22- to 30-year period.
In
those with severe or long-standing valvular obstruction,
infundibular hypertrophy may cause secondary obstruction
when the pulmonary valve is successfully dilated. This
frequently regresses over time without treatment. Some
have advocated transient pharmacological ß-blockade,
but there is insufficient information to determine whether
this is effective or necessary.
From
the Natural History Study data, it would appear that
congenital mild pulmonary stenosis is a benign disease
that rarely progresses, that moderate or severe pulmonary
stenosis can be improved with either surgery or balloon
valvotomy at very low risk, and that patients who undergo
surgery or balloon valvotomy have an excellent prognosis
and a low rate of recurrence. Thus, the goal of the
clinician is to ascertain the severity of the disease,
treat those in whom it is severe, and infrequently follow
up those with mild disease (590).
Recommendations
for Intervention in the Adolescent or Young Adult With
Pulmonic Stenosis (Balloon Valvotomy or Surgery)
Recommendations
for Follow-up Exams in Pulmonic Stenosis
G.
Pulmonary Regurgitation
Pulmonary
valve regurgitation is an uncommon congenital lesion
seen occasionally with what has been described as idiopathic
dilation of the pulmonary artery. In this condition,
the annulus of the pulmonary valve dilates, causing
the leaflets to fail to coapt during diastole. Mild
pulmonary regurgitation may be a normal finding on Doppler
echocardiography.
Although
pulmonary regurgitation is unusual as an isolated congenital
defect, it is an almost unavoidable result of either
surgical or balloon valvuloplasty of valvular pulmonic
stenosis or surgical repair of tetralogy of Fallot.
Among patients with pulmonic stenosis who underwent
surgical valvotomy in the first Natural History Study,
87% had pulmonary regurgitation by Doppler echocardiography
in the second Natural History Study, although it was
audible in only 58%. The echocardiogram tended to overestimate
severity when compared with auscultation, with 20% considered
moderate to severe by Doppler but only 6% by auscultation.
In those with pulmonary regurgitation, the right ventricle
tended to be larger but right ventricular systolic dysfunction
was uncommon; it was present in only 9%.
Pulmonary
regurgitation also commonly occurs after successful
repair of tetralogy of Fallot. Several studies have
documented that the vast majority of children and young
adults operated on in the late 1950s and 1960s continue
to do well for up to 35 years after surgery (591).
However, a small group with long-standing pulmonary
regurgitation has developed a very dilated right ventricle
and diminished right ventricular systolic performance,
which can lead to an inadequate ability to augment cardiac
output with exercise and in some cases congestive heart
failure. This group has also been shown to have a significant
incidence of ventricular arrhythmias known to be associated
with late sudden death. Increased pulmonary artery pressure
from LV dysfunction or residual peripheral pulmonary
artery stenosis will increase the amount of regurgitation,
and these conditions should be treated when present.
Pulmonary valve replacement, usually with a homograft,
has been attempted, but follow-up data are too preliminary
to develop recommendations at this time.
©
1998 American College of Cardiology and American Heart
Association, Inc. Published by Elsevier
Science Inc.
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