Heart Murmurs: Acquired Heart Disease

Comments

Transcription

Heart Murmurs: Acquired Heart Disease
15
Heart Murmurs: Acquired
Heart Disease
Alan J. Spotnitz
Objectives
1. To understand the potential significance of a heart
murmur in the absence of symptoms.
2. To understand the factors relevant to the selection
of a heart valve.
3. To recognize the need for anticoagulants in
patients following valvular heart surgery.
4. To understand the risks of valvular heart surgery
and its indications.
Cases
Case 1
A 55-year-old man presents to your office complaining of fatigue and
shortness of breath after playing one set of tennis. Up until a year ago,
he played three sets without difficulty. He was refused induction into
the Marines because of a heart murmur. He denies chest pain and is
otherwise asymptomatic.
Case 2
A 70-year-old woman presents to your emergency room. She is acutely
short of breath and unable to lie flat. She is cold and diaphoretic. The
symptoms began a few hours ago following some “indigestion.” Her
blood pressure is 80/50. She had the same feeling of “indigestion”
a few days ago that lasted 3 to 4 hours. She has been in excellent
health prior to this time and denies any prior cardiac or respiratory
problems.
264
15. Heart Murmurs: Acquired Heart Disease
Introduction
Heart murmurs can be found at any age. They are caused by turbulent
or abnormal flow in the heart. A murmur may or may not represent a
critical structural abnormality. Chapter 14 described lesions that are
congenital in nature and likely to cause murmurs in the neonate or
child. This chapter discusses heart murmurs related to acquired heart
disease that become apparent in the adult population.
Acquired disease of the heart valves can be a major clinical problem
frequently requiring surgical correction. Despite the near elimination
of rheumatic fever and rheumatic heart disease (historically, the major
cause of acquired valvular heart disease in this country), valve surgery
represented 15% of the cases reported in the Society of Thoracic
Surgeons (STS) database from 1990 to 1999.1 Of the four cardiac valves,
the aortic and mitral valves most commonly are involved. Structural
changes in the tricuspid valve can occur, but the leading causes of
tricuspid valvular disease are changes secondary to left-sided heart
failure and pulmonary hypertension secondary to valvular disease of
the aortic or mitral valve. The pulmonic valve rarely is involved.
Onset of symptoms can be quite sudden (Case 2) when attributable to acute changes in structural anatomy of the valve (endocarditis, aortic dissection, and ruptured papillary muscle or chordae
tendinae). More often, patients present with progressive symptoms,
although an acute episode of heart failure or pulmonary edema may
draw attention to the disease process. In either situation, proper
workup and appropriate medical and surgical therapy are crucial to
the long- and short-term well-being of the patient. Symptoms are classified I to IV similar to The American Heart Association classification
used for angina (see Table 16.1).
Anatomy of the Valves
Each heart valve is made of similar tissue components. The leaflets
consist of endothelial cells on a thin, delicate, fibrous skeleton. Each
leaflet is attached to the thicker fibrous skeleton of the valve annulus.
Figure 15.1 shows the anatomic relation of the four heart valves in a
cross section taken through the base of the heart. The aortic and mitral
valves share a common fibrous skeleton. They come within greatest
approximation at the noncoronary sinus of the aortic valve: the anterior leaflet of the mitral valve can be viewed, at the time of aortic valve
surgery, as lying just below the noncoronary sinus.
The normal aortic valve is a three-leaflet structure consisting of the
left, right, and noncoronary leaflets. It usually is 2.5 to 3.5 cm2 in area.
Each leaflet is associated with its respective coronary sinus. Although
variations can occur, the right coronary artery arises from the right
1
The Society of Thoracic Surgeons National Adult Cardiac Surgery Database, 1999. Voluntary registry of results from more than 500 participating cardiac surgery programs
nationwide. Data available at www.sts.org.
265
266
A.J. Spotnitz
Figure 15.1. Anatomy of the cardiac valves, viewed as transverse section at the
level of the base of the heart. (Reprinted with permission from Hollinshead
WH. The Heart and Great Vessels. In Hollinshead WH: Anatomy for Surgeons,
Volume Two, The Thorax, Abdomen and Pelvis, second edition. New York:
Harper and Row: 1971:129.)
coronary sinus, which lies anatomically anterior in the aortic root. The
left coronary artery arises from the left sinus and is located relatively
posterior. The noncoronary sinus is toward the right side of the aortic
root and lies closest to the surgeon when viewed in the operating room.
The bundle of His lies just below the aortic annulus in the right
coronary sinus adjacent to its junction with the noncoronary sinus. This
relationship explains the potential for the development of heart block
related to aortic valvular disease or to complications of aortic valve
replacement. Often, increasing heart block is an indication of a progressive aortic root abscess in the presence of endocarditis, even if
the patient appears to be improving otherwise, and is an indication for
urgent surgery.
The mitral valve is anatomically more complex than the aortic valve.
The normal valve area is 4.0 to 6.0 cm2. In cross section, it looks like a
parachute with the larger anterior leaflet and smaller posterior leaflets
tethered to the papillary muscles and mitral valve annulus by the
chordae tendinae. Disruption or stretching of the chordae or papillary muscle results in mitral insufficiency due to the loss of the tethering mechanisms, which then permits prolapse of the valve leaflet
back into the atrium.
The right-sided heart valves are comparable to those on the left side
but less prone to isolated structural problems. The pulmonic valve is a
trileaflet valve similar in appearance to the aortic valve. It does have
sinuses but no coronary ostia. The tricuspid valve has three leaflets of
unequal size with a supporting apparatus similar to the mitral valve.
Significant pulmonary hypertension can lead to secondary dilatation
of the tricuspid annulus and result in tricuspid insufficiency.
Differential Diagnosis
In any adult patient presenting with new-onset congestive heart failure,
exercise intolerance (Case 1), cardiogenic shock (Case 2), increasing
fatigue, or angina, a significant valve problem must be considered. The
differential diagnosis of an adult patient with a heart murmur can be
15. Heart Murmurs: Acquired Heart Disease
267
approached in a relatively simple way. (See Algorithm 15.1.) The first
step is to determine if the murmur represents a significant pathologic
problem. A murmur can be totally benign and of no clinical significance. Next, it must be determined if a heart valve abnormality is, in
fact, the cause of the murmur. Other causes do exist, such as congenital heart disease that was not recognized during childhood or an
acquired ventricular defect following a myocardial infarction. The presence of a heart murmur can signify a benign or malignant tumor of the
heart. Careful history and physical examination will determine the
clinical significance of the murmur. Finally, the valve involved and
the cause of the murmur must be defined. Table 15.1 lists the
numerous etiologies of disease of each of the heart valves.
Follow
Heart murmur
CHF
ECG, CXR
NSR
Depending on
severity of symptoms
admit or not
begin medical
treatment
Cardiac catheter
Yes
Echo, TEE
Admit
Rate control
Heparin + Coumadin
Echo
Normal LV
History Afib
Acute or
chronic
anticoag
Normal
No
Symptoms
Afib
Echo/TEE
Enlarged
Left ventricle
Normal
No CHF
Echo, TEE
Enlarged LV
Normal
AS
AI
MS
Consider cardioversion
if no thrombus
Medical treatment
Follow
Enlarged LV
Consider catheter
or surgical treatment
Medical treatment
class II
Yes
Elective surgery Further evaluation
Medical treatment
Possible early surgery
if mitral stenosis
or mitral regurgitation
Cath, OR
Cath? OR
Cath? OR
No or unsuccessful:
catheter
Catheter
OR
TEE
If symptoms persist
Catheter
OR
Coumadin
Medical treatment
Coumadin
Algorithm 15.1. Algorithm for diagnosis and treatment of adults with heart murmurs. CHF,
congestive heart failure; ECG, electrocardiogram; NSR, normal sinus rhythm; TEE, transesophageal
echocardiography.
Table 15.1. Prevalent etiologies of valvular heart disease.
Mitral stenosis
Valvular
Rheumatic disease
Nonrheumatic disease
Infective endocarditis
Congenital mitral stenosis
Single papillary muscle (parachute valve)
Mitral annual calcification
Supravalvular
Myxoma
Left atrial thrombus
Mitral insufficiency
Valvular
Rheumatic fever
Endocarditis
Systemic lupus erythematosis
Congenital
Cleft leaflet (isolated)
Endocardial cushion defect
Connective tissue disorders
Annular
Degeneration
Dilation
Subvalvular
Chordae tendinae
Endocarditis
Myocardial infarction
Connective tissue disorder
Rheumatic disease
Papillary muscle
Dysfunction or rupture
Ischemia or infarction
Endocarditis
Inflammatory disorder
Malalignment
Left ventricular dilation
Cardiomyopathy
Aortic stenosisa
Acquired
Rheumatic disease
Degenerative (fibrocalcific) disease
Tricuspid valve
Congenital bicuspid valve
Infective endocarditis
Congenital
Tricuspid valve with commissural fusion
Unicuspid unicommissural valve
Hypoplastic annulus
Aortic insufficiency
Valvular
Rheumatic disease
Congenital
Endocarditis
Connective tissue disorder (Marfan’s)
Annular
Connective tissue disorders (Marfan’s)
Aortic dissection
Hypertension
Inflammatory disease (e.g., ankylosing spondylitis)
a
Excludes subvalvular and supravalvular processes.
Source: Reprinted from Rosengart TK, de Bois W, Francalancia NA. Adult heart disease.
In: Norton JA, Bollinger RR, Chang AE, et al, eds. Surgery: Basic Science and Clinical
Evidence. New York: Springer-Verlag, 2001, with permission.
15. Heart Murmurs: Acquired Heart Disease
Aortic Stenosis
Surgery involving the aortic valve is the second most common procedure performed in adults (isolated coronary artery bypass graft is
number one) and represents approximately 60% of the valve cases
reported in the STS database. The etiology of aortic stenosis is multifactorial and often can be inferred by the age of onset of symptoms.
The primary causes are a congenitally deformed bicuspid valve,
rheumatic valvular disease, and degenerative disease of a threeleaflet valve. Patients who present in the fourth or fifth decade of life
often have a congenital bicuspid aortic valve that becomes progressively stenotic. The etiology is referred to as congenital in nature.
Those developing symptoms at a later age are likely to have had
rheumatic heart disease and often have combined aortic stenosis and
regurgitation. Patients presenting in the eighth or ninth decade
usually have had a normal three-leaflet valve that has become calcified, and this etiology is referred to as “senile degenerative disease.”
Aortic stenosis has a well-recognized triad of symptoms that
develop progressively as the area of the aortic valve drops below
1.0 cm2: angina, heart failure, and syncope. The obstruction to outflow
from the left ventricle results in significant pressure loading and the
development of ventricular hypertrophy. Intracavitary systolic pressures can reach 300 mm Hg or more. Onset of one or all of these symptoms usually occurs after many years of an increasingly stenotic
valve and is a poor prognostic sign. Angina may be one of the first
symptoms to develop. Symptoms of shortness of breath or angina are
precipitated by exercise when the fixed area of the valve prevents an
increase in forward cardiac output. Once frank ventricular failure
occurs with increasing diastolic volumes, rapid deterioration of left
ventricular function can occur, and the prognosis for the patient
worsens. Decrease in the function of the left ventricle is the leading
indicator of increased operative mortality and decreased long-term
survival in all patients undergoing cardiac surgery. The exact cause
of syncopal episodes remains unclear. It has been attributed to, but not
proven to be related to, arrhythmias, sudden lack of ejection, or unexplained low cardiac output. The presence of angina, heart failure, and
syncope in a patient with aortic stenosis should be considered life
threatening, and urgent surgical correction should be performed.
The natural history of aortic stenosis is well recognized, with almost
100% mortality within 5 years of symptom onset without surgical valve
replacement. Once symptoms occur, they should be treated appropriately with diuretics and antianginal medications while assessment of
the patient progresses. Care must be taken, however, to avoid excessive use of nitrates and diuretics, since the loss of preload can lead
to hypotension and death.
Aortic Insufficiency
Aortic insufficiency can cause symptoms of heart failure and cardiac
enlargement, but the process is quite different from the process
leading to aortic stenosis. Whereas pressure overload is the inciting
269
270
A.J. Spotnitz
factor in aortic stenosis, volume overload is the culprit in aortic insufficiency. Leakage through the valve results from one of many causes
that affect the leaflets directly (rheumatic disease, endocarditis, and
connective tissue disorders) or the annulus of the valve (connective
tissue disorders, especially Marfan’s syndrome, hypertension, and
inflammatory diseases). This volume overloading results in dilation of
the ventricle followed by thickening of the ventricular wall. This compensation can be quite effective and result in a massively enlarged heart
and progression of ventricular enlargement without significant symptoms. The natural history of aortic insufficiency is less clear than that
of aortic stenosis, and patients may survive many years with significant regurgitation without symptoms until late in the natural course of
the disease.
The scenario described in Case 1 would not be unusual for a patient
with aortic insufficiency, especially at a younger age. Symptoms
usually are related to onset of congestive heart failure. In some patients,
angina may be present due to reversal of flow in the coronary arteries
secondary to a very low aortic diastolic pressure that may occur.
Mitral Stenosis
Mitral stenosis most commonly is caused by rheumatic valvular
disease. Scarring due to endocarditis can occur. An atrial myxoma prolapsing into the mitral annulus can mimic the signs of valvular stenosis. The major symptoms are those of congestive heart failure, but
left ventricular failure per se does not occur. Symptoms may develop
when the valve area drops below 2 cm2 and is related to increasing pressure in the left atrium. Pressure gradients across the mitral valve in
excess of 20 mm Hg can occur. Pulmonary congestion occurs when this
pressure is transmitted back into the pulmonary circulation, especially
when exercise is attempted, and the fixed output by the valve results
in dramatic increases in the pulmonary artery pressure. Classically,
hemoptysis would develop in late stages of the disease. Atrial dilatation is likely to occur, and subsequent atrial fibrillation will develop.
New-onset atrial fibrillation is not an uncommon presentation for
mitral stenosis. Occasionally, embolization of left atrial thrombus
that develops secondary to the atrial fibrillation can be the presenting sign. Medical therapy is directed to the treatment of congestive
heart failure and atrial fibrillation while the diagnostic workup progresses and a decision regarding surgery is reached.
Mitral Insufficiency
Because of the complex structure of the mitral valve, the causes of
mitral insufficiency are numerous, affecting the valve leaflets, the
supporting structure, or the annulus, or a combination thereof.
Rheumatic valvular disease and endocarditis tend to affect the leaflet
directly, but they also can affect the valve’s supporting structures. Ruptured chordae tendinae or papillary muscle results in significant regurgitation, as may myocardial infarction affecting the ventricular wall at
the base of the papillary muscle. Myxomatous degeneration of the
15. Heart Murmurs: Acquired Heart Disease
valve can result as a sequela of mitral valve prolapse. Significant ventricular dilation that affects the annulus of the valve can lead to profound symptoms. As with aortic insufficiency, significant leakage can
occur through the valve without significant symptoms if onset is
gradual. Eventually, excessive volume overload affects both the left
ventricle and the left atrium. Thinning of the left atrium occurs and can
result in atrial fibrillation. Severe pulmonary hypertension may
develop from volume and pressure overload of the pulmonary circulation. When patients reach the later stages of this disease, operative
mortalities become extremely high, and the chance for recovery of
substantial ventricular function or relief of symptoms is less likely,
especially in the presence of associated coronary artery disease.
Tricuspid Regurgitation
Right-sided valvular disease, for the most part, is confined to the tricuspid valve. The typical lesion is tricuspid regurgitation secondary
to pulmonary hypertension and annular dilatation. Rheumatic
disease or endocarditis can affect the valve. Traumatic rupture of the
supporting structures can occur, especially following blunt trauma.
Other Differential Diagnoses
The remaining causes of heart murmurs are infrequent. Congenital
anomalies missed in childhood can prompt the need for evaluation.
Atrial septal defects may well be missed and not become apparent
until signs of congestive failure develop or a stenotic murmur (related
to increased flow but no structural abnormality) occurs in the pulmonic
area. The murmur of a postinfarction ventricular septal defect may
not be recognized until a patient is in the recovery phase of a myocardial infarction (MI). Finally, the intermittent mitral stenosis murmur
related to an atrial myxoma that intermittently obstructs diastolic flow
across the mitral valve should not be missed.
Acute Changes in Valve Competency
As opposed to the gradual changes and onset of symptoms with
chronic valve disease, acute changes in valve competency are not
handled well by the heart. Amounts of insufficiency tolerated in the
chronic situation where the heart has been able to gradually compensate over time are not tolerated in the acute situation. Acute aortic
regurgitation associated with bacterial endocarditis or aortic dissection
and acute mitral regurgitation that accompanies a ruptured papillary
muscle may lead to the acute onset of severe symptoms of heart failure
and shock.
Case 2 describes a patient developing acute mitral regurgitation
several days after an MI. This must be differentiated from a post-MI
ventricular septal defect by echocardiography, measurements of
oxygen saturation in the right heart chambers (a step up from the right
atrium to the right ventricle), or left ventriculogram (or all of the
above). Emergency surgery may provide the only option despite the
high risk (30–75%) in these acute situations.
271
272
A.J. Spotnitz
Diagnostic Methods
History and Physical Examination
Evaluation of a patient with a heart murmur requires a complete but
focused history and physical examination. The present illness should
be detailed, including a search for the onset of symptoms (if any).
Subtle changes in exercise tolerance need to be explored. Factors that
bring on the symptoms or relieve them should be sought. Specifics
related to the etiology of the valvular disease should be sought: a
history of rheumatic fever, familial history of connective tissue
disease, history of endocarditis, history of heart murmur, etc. As in
Case 1, a history of heart murmur described as nonsignificant in the
past may be present. A careful review of systems, past medical history,
and social history is crucial to help make decisions regarding future
therapy.
The physical exam is directed toward the heart and systems that
reflect signs of valvular heart disease or secondary congestive heart
failure as well as findings that might increase surgical risk. Initial
observation of the patient for presence or absence of muscle wasting is
important. Many patients report weight loss in later stages of the
disease because of an inability to eat related to respiratory symptoms.
Examination of the head and neck for venous distention, carotid bruits,
delayed carotid upstroke (aortic stenosis), water-hammer pulse (aortic
insufficiency), and thyromegaly (as source of atrial fibrillation) is
important.
The dentition of the patient needs to be checked. If valve surgery
is contemplated, all dental work should be done prior to the implantation of a new valve to minimize the risk of prosthetic valve endocarditis. Pulmonary exam tries to elicit the rales and rhonchi frequently
associated with congestive heart failure. Abdominal and peripheral
exams are intended to find signs related to right-sided heart failure,
including hepatosplenomegaly and peripheral edema. Peripheral
pulses are evaluated, and the presence or absence of varicose veins
should be noted in case bypass surgery is required.
The cardiac exam should note any cardiac enlargement. The presence
or absence of a gallop rhythm indicative of heart failure is listened for.
Last, heart murmurs are listened for and described. Murmurs are rated
on a scale of I to VI, where I is barely perceptible with a stethoscope and
VI describes a thrill (palpable murmur). The typical aortic stenosis
murmur is heard loudest over the second intercostal space to the right
of the sternum and may radiate to the neck. It usually is a crescendo/
decrescendo murmur that may range from mid- to holosystolic. Systole
may be quite prolonged. An aortic insufficiency murmur usually is
loudest in the fourth intercostal space to the left of the sternum, and
is a diastolic decrescendo murmur that can be heard best with the
patient leaning forward, and may be associated with a widened pulse
pressure. Mitral stenosis is heard loudest at the apex of the heart,
which usually is not displaced, since left ventricular enlargement
is unusual. The murmur is a low-pitched, rumbling diastolic murmur
15. Heart Murmurs: Acquired Heart Disease
that may be accentuated by expiration. An opening “snap” may be
present. A mitral insufficiency murmur is holosystolic, blowing,
loudest at the apex, and may radiate to the axilla.
Chest X-Ray
Frequently, the history and physical give an accurate picture by which
the diagnosis can be made. The chest x-ray can be helpful for confirming signs of cardiomegaly, chamber enlargement, pulmonary
congestion, etc. An associated aortic dilatation of an ascending aortic
aneurysm associated with aortic insufficiency may be present.
Electrocardiogram
An electrocardiogram clarifies any cardiac rhythm abnormalities.
Conduction defects, especially in the presence of active endocarditis,
should be sought. Left and right ventricular or atrial enlargement may
be suggested. Other changes are suggestive of associated coronary
artery disease that also must be addressed.
Echocardiogram
The easiest and currently most accurate noninvasive test used in
evaluating valvular heart disease is the echocardiogram, more specifically the transesophageal echocardiogram. These studies permit a
simple screening for the presence and severity of a valvular lesion. At
the same time, the presence of chamber enlargement or dysfunction can
be determined. A simple method thus exists to permit the ongoing evaluation of patients not yet deemed candidates for surgery. The presence
or absence of calcification that might increase the complexity of surgery
can be identified, and information can be provided on the suitability
of a patient for mitral valve repair. If these studies indicate the need,
cardiac catheterization usually is recommended. If surgery is not
needed at the time of initial evaluation, echocardiogram provides a
simple method for ongoing evaluation.
Cardiac Catheterization
Both left and right heart catheterizations are performed on most
patients being evaluated for valve surgery. Right heart catheterization usually employs a Swan-Ganz catheter inserted via a large vein
into the right heart. Measurements of right-sided chamber pressures,
the pulmonary artery pressure, and the pulmonary capillary wedge
pressure (which reflects the left atrial pressure) are made. Often,
oxygen saturation in each location also is measured. A thermodilution
cardiac output is determined. In a left heart catheterization, a catheter
is passed from the femoral or brachial artery back though the aorta to
the heart. It is used to measure pressures in the aortic root and left ventricular chamber. Any gradient indicative of stenosis across the aortic
valve is measured. The gradient across the mitral valve is the difference between simultaneous measurements of pulmonary capillary
wedge pressure (the equivalent of left atrial pressure) and left ventric-
273
274
A.J. Spotnitz
ular end-diastolic pressure. Across the aortic valve, a pullback reading
is obtained on several occasions. The valve areas then can be calculated using the Gorlin formula that relates the area of the valve to
the pressure gradient across the valve and the cardiac output. Coronary angiography is performed to look for any associated coronary
disease that could be repaired simultaneously during surgery. In some
younger patients and in some emergency situations, the information
provided by the echocardiogram may be sufficient and heart catheterization may not be required.
Therapeutic Intervention
Indication for Surgery
Decisions regarding the management of patients with valvular heart
disease are based on the recognized progression of the various
lesions and the risk versus benefit of surgical intervention. Until the
ideal replacement valve is developed, the inherent risks associated
with prosthetic valves (limited durability, need for anticoagulation,
propensity for infection, sound) must be considered along with the
risk of the operation itself. One pathologic situation (the deformed
valve) is being substituted with another (the prosthetic valve when
needed), although with a different array of potential problems. The
surgical risk is associated with age (increases significantly by decade
over 70 years of age), ventricular function (ejection fraction <40%),
diabetes, renal failure or insufficiency, peripheral vascular disease,
chronic obstructive pulmonary disease (COPD), etc. Associated coronary artery disease, especially in the presence of mitral regurgitation,
significantly increases operative mortality. Thus, the decision is one
of the benefits of preventing further deterioration in ventricular
function, death, or other complications related to the valve disease
versus the risk of surgery, the patient’s likelihood to regain or maintain an acceptable lifestyle, and the risks inherent in the new valve
substituted.
Patients with new-onset symptoms are treated medically to relieve
symptoms of congestive heart failure or angina. Congestive heart
failure is treated with diuretics, digoxin, and afterload reduction when
it can be tolerated. Angina is treated appropriately. Great care must be
taken in patients with aortic stenosis to avoid overdiureseis or too
much preload reduction (with nitroglycerine and diuretics), which can
result in inadequate filling of the left ventricle and subsequent syncope
or low output. Heart rate must be controlled with beta-blockers digoxin
or calcium channel blockers to permit adequate chamber filling, especially when stenotic lesions are present. Anticoagulants are needed for
patients in atrial fibrillation to prevent systemic embolization. There is
some evidence that the use of the calcium channel blocker Procardia in
asymptomatic patients with aortic insufficiency may delay their need
for surgery.
Once diagnostic studies have been completed, recommendations
for chronic medical therapy or surgery are made. These decisions
15. Heart Murmurs: Acquired Heart Disease
must be made on an individual basis and must involve an informed
consent from the patient and family. Medical therapy is used for
those patients when it is believed the surgical risk is too high or their
long-term benefit is not sufficient for surgery. Others who are not yet
ready for surgery receive medical therapy but are followed closely
until indications for surgery become manifest.
As noted, the surgical management of valvular heart disease is
dependent on the risk-benefit ratio for the patient. Unfortunately, this
is not always so clear when the risk of the operation is high and the
benefit to an individual patient not clear. However, generalized indications for surgery have evolved based on short- and long-term
outcome studies. Detailed diagnostic and therapeutic guidelines are
well summarized in “Consensus Statement on Management of
Patients with Valvular Heart Disease,” developed by a combined task
force of the American Heart Association and the American College of
Cardiology.2
Aortic Stenosis and Aortic Insufficiency
In aortic stenosis, the rapidity with which patients deteriorate and die
suddenly after the onset of symptoms has made the decision making
relatively easy. Any patient with symptomatic aortic stenosis should
undergo valve replacement unless there are significant contraindications or the patient’s life expectancy is otherwise severely limited. Even
those patients with significant organ dysfunction secondary to the low
output state may be considered. In the past, it also was believed those
asymptomatic patients with aortic stenosis and a valve area of less than
1 cm2 or a gradient >60 mm Hg also should undergo valve replacement.
More recently, with the ability to follow patients closely with echocardiography, surgery may be delayed until symptoms develop without
increased risk to the patient as long as surgery occurs rapidly following the onset of symptoms.
In aortic insufficiency, the decision making is not so clear. Studies
have shown that a patient with aortic insufficiency and a normal ventricle can undergo replacement with little surgical risk. On the other
hand, once the ventricle begins to fail, the risk increases dramatically.
Even in the absence of symptoms, increased operative mortality occurs
in the presence of indicators of deteriorating ventricular function. As a
result, valve surgery is recommended for all class III and IV symptomatic patients and all patients with one of the following signs even
in the absence of symptoms: increasing size of the heart, decreasing ejection fraction under observation, ejection fraction of less
than 40%; or an end-systolic diameter of greater than 55 mm by
echocardiography.
At the present time, valve replacement is the recommended treatment for surgical correction of aortic valvular diseases. There are a
few patients with aortic insufficiency in whom valvuloplasty has been
successful, although replacement remains the standard.
2
American Heart Disease/American College of Cardiology. Consensus Statement on
Management of Patients with Valvular Heart Disease. Circulation 1998;98:1949–1984.
Also available at www.americanheart.org.
275
276
A.J. Spotnitz
Mitral Stenosis and Mitral Insufficiency
Mitral valve disease is different from aortic valvular disease in that
reconstructive surgery often can be done instead of replacement of
the valve. The operative mortality has been less with a repair when the
long-term risks of a prosthetic valve are avoided. Mitral stenosis was
the first valve problem approached surgically and was performed successfully in the late 1940s several years before the first successful use
of the heart lung machine (by Gibbon3 in 1953). In any case, either direct
commissurotomy and reconstruction, if needed, of the subvalvular
apparatus are performed, or valve replacement is done. Because of the
success of mitral valvuloplasty for mitral stenosis and the detailed
diagnostic images of the valves now obtainable by echocardiography,
certain patients with mitral stenosis are treated using percutaneous
methods in the catheterization laboratory using balloon dilators (larger
balloons but similar technique to angioplasty) with good success. The
indications for surgery in the presence of mitral stenosis are class II
symptoms if a commissurotomy is possible either surgically or using
a balloon or all class III and IV patients even if valve replacement is
likely to be needed.
Surgical treatment of mitral insufficiency is the most difficult condition about which to make decisions. Many patients are without
symptoms despite large amounts of regurgitation and decreased left
ventricular function. Unlike other situations, the operative risk in
patients with mitral regurgitation is related to the underlying cause of
the disease and may be two to three times greater when the etiology
is ischemic in nature. Ultimately, at later stages of the disease, the
operative risk and the likely lack of prolongation of life or relief of
symptoms make surgery inappropriate for some of these patients,
although some recent investigational studies suggest certain methods
of valvuloplasty may be applicable in this patient population despite
the high risk. Early surgery is indicated in patients with American
Heart Association class II symptoms if repair of the valve seems
likely. In all others, the recommendation is to await class III symptoms. All class III and IV patients should be considered for surgery.
On the other hand, increasing ventricular chamber size or end systolic diameter >55 mm in the absence of symptoms is an indication
for surgical correction, similar to the decision making for aortic
insufficiency.
Repair of the mitral valve has been shown to carry a lower operative mortality compared to replacement. It is the preferred operation
when it can be done expeditiously. If not, valve replacement should be
carried out. If replacement is performed, many surgeons recommend
that as much of the subvalvular apparatus is retained at the time of
valve replacement (especially if a tissue valve is used) in order to maintain the normal architecture of the ventricle following surgery. This is
believed to lead to improved short- and long-term success.
3
Gibbon JH Jr. Application of a mechanical heart and lung apparatus to cardiac surgery.
Minn Med 1954;37:171.
15. Heart Murmurs: Acquired Heart Disease
Selection of Valve Prosthesis
Guidelines for the selection of prosthetic valves have been generalized
but should be discussed carefully with each patient before surgery and
be part of the informed consent. In general, there are two types of prosthetic valves available: mechanical and tissue. The advantages of the
former include longer durability and perhaps lower residual gradient size for size compared to stented tissue valves. The disadvantage
of the mechanical valve is the requirement for lifelong anticoagulation to prevent valve thrombosis or embolization of thrombus from
the valve. In addition, the closing click of the valve may be audible
and objectionable to certain patients or their partners. Tissue valves
do not require anticoagulation (after the first 3 months of implantation) if a patient remains in sinus rhythm. They are silent. Their
durability, however, is limited. Definitive information on durability is
available only for the original first generation porcine valves and is
related to the patient’s age at valve implantation. In patients older than
70 years of age, a tissue valve failure is likely less than 10% of the time
in the first 10 years. On the other hand, in patients younger than 35
years of age, more than 50% require replacement at a second operation
within 5 years. Second-generation tissue valves have shown less of a
propensity for deterioration, especially in elderly patients, and frequently outlast the patient’s lifetime. The decision making, however,
also is now complicated by the extended lifetime of many elderly
patients. In general, the recommendations are that a mechanical valve
be used on all patients younger than 65 years of age, unless anticoagulation is contraindicated. In most patients older than 65 or 70
years of age, tissue valves are recommended, unless anticoagulation
for other problems (such as chronic atrial fibrillation) is required or
unless it is likely the patient will outlive a tissue valve.
Results
For isolated aortic valve replacement, operative mortality ranges from
2% to 5.5%. For isolated mitral valve replacement, the range is 3.5%
to 7.5%. Isolated mitral valvuloplasty has even better results. The
exception is patients in later stages of mitral regurgitation, especially if
ischemic in origin, in whom the 5-year survival is as low as 20%. See
Tables 15.2, 15.3, and 15.4.
Long-Term Care
The goals of long-term care and follow-up in these patients are aimed
at minimizing those risks associated with a prosthetic valve or valve
repair. In the first 6 months following surgery, the risk of prosthetic
valve endocarditis is significantly higher than later time frames and
carries a grave prognosis (mortality 50% to 80%). Beyond this time, the
risks of endocarditis and methods of treatment are the same as for any
deformed native valve. Antibiotic prophylaxis is an absolute must for
these patients when any dental work is performed. The same is true
for any invasive procedure that might be associated with an episode
277
578
376
589
1979–1995
1982–1990
1984–1993
349
611
254
1982–1991
1979–1990
1989–1994
n
2.3
4
5
3.4
5.4
3.9
Operative
mortality
(%)
10 yr, 84% ± 6%
10 yr, 71% ± 7%
Auportf
Davide
8 yr, 91% ± 4%
8 yr, 93% ± 3%d
10 yr, 76% ± 2%
15 yr, 53% ± 4%
Jamieson
Bernalc
15 yr, 55% ± 4%
5 yr, 96% ± 1%
5 yr, 69% ± 4%
Fernandeza
Kratzb
Source
—
—
10 yr, 92% ± 2%
Freedom from
reoperation
—
10 yr, 35% ± 8%
Freedom from
valve-related
complications
10 yr, 64% ± 22%
15 yr, 39% ± 3%
8 yr, 79% ± 3%
5 yr, 78%
5 yr, 80% ± 3%
10 yr, 47% ± 9%
5 yr, 77% ± 4%
Actuarial
survival
Purcaro A, Costantini C, Ciampani N, et al. Diagnostic criteria and management of subacute ventricular free wall rupture complicating myocardial infarction. Am J
Cardiol 1997;80:397–405.
b
Yeo TC, Malouf JF, Oh JK, et al. Clinical profile and outcome in 52 patients with cardiac pseudoaneurysm. Ann Intern Med 1998;128:299–305.
c
Schwarz CD, Punzengruber C, Ng CK, et al. Clinical presentation of rupture of the left ventricular free wall after myocardial infarction: report of five cases with successful surgical repair. Thorac Cardiovasc Surg 1996;44:71–75.
d
Freedom from thromboembolism.
e
Komeda M, David TE. Surgical treatment of postinfarction false aneurysm of the left ventricle. J Thorac Cardiovasc Surg 1993;106(6):1189–1191.
f
Auport MR, Sirinelli AL, Diermont FF, et al. The last generation of pericardial valves in the aortic position: ten year follow-up in 589 patients. Ann Thorac Surg
1996;61:615–620.
Source: Reprinted from Rosengart TK, de Bois W, Francalancia NA. Adult heart disease. In: Norton JA, Bollinger RR, Chang AE, et al, eds. Surgery: Basic Science and
Clinical Evidence. New York: Springer-Verlag, 2001, with permission.
a
Bioprosthetic
Porcine
(Carpentier-Edwards)
Porcine
(Hancock)
Bovine pericardial
(Carpentier-Edwards)
Carbomedics
Valve type
Mechanical
St. Jude
St. Jude
Years of
enrollment
Table 15.2. Selected series of aortic valve replacement.
278
A.J. Spotnitz
512
195
1982–1990
514
397
330
1980–1996
1979–1990
1989–1994
1975–1995
n
6
9
7.2
3.5
6.9
Operative
mortality
(%)
10 yr, 52% ± 2%
15 yr, 24% ± 3%
8 yr, 68% ± 4%d
8 yr, 89%
10 yr, 73% ± 6%
5 yr, 77% ± 4%
Actuarial
survival
15 yr, 20% ± 4%
8 yr, 92% ± 5%
8 yr, 83% ± 5%e
—
—
—
Freedom from
reoperation
—
—
3.7% (pt-yr)
10 yr, 69% ± 4%
Freedom from
valve-related
complications
Davidf
Jamieson
Grossia
Jegadenb
Bernalc
Source
a
Grossi EA, Galloway AC, Miller JS, et al. Valve repair versus replacement for mitral insufficiency: when is a mechanical valve still indicated? J Thorac Cardiovasc Surg
1998;115:389–396.
b
Lopez-Sendon J, Gonzalez A, Lopez de Sa E, et al. Diagnosis of subacute ventricular wall rupture after acute myocardial infarction: sensitivity and specificity of
clinical, hemodynamic and echocardiographic criteria. J Am Coll Cardiol 1992;19:1145–1153.
c
Schwarz CD, Punzengruber C, Ng CK, et al. Clinical presentation of rupture of the left ventricular free wall after myocardial infarction: report of five cases with successful surgical repair. Thorac Cardiovasc Surg 1996;44:71–75.
d
Freedom from late cardiac death.
e
Freedom from thromboembolic complications.
f
Csapo K, Voith L, Szuk T, et al. Postinfarction left ventricular pseudoaneurysm. Clin Cardiol 1997;20:898–903.
Source: Reprinted from Rosengart TK, de Bois W, Francalancia NA. Adult heart disease. In: Norton JA, Bollinger RR, Chang AE, et al, eds. Surgery: Basic Science and
Clinical Evidence. New York: Springer-Verlag, 2001, with permission.
Bioprosthetic
Porcine
(Carpentier-Edwards)
Porcine
(Hancock)
Valve type
Mechanical
St. Jude
St. Jude
Carbomedics
Years of
enrollment
Table 15.3. Selected series of mitral valve replacement.
15. Heart Murmurs: Acquired Heart Disease
279
324
1981–1995
0.6
0.5
5.4
Operative
mortality
(%)
5.5
Freedom from
reoperation
15 yr, 87% ± 3%
76%b
95% ± 2%
96% ± 1%
Ten-year
actuarial
survival
72% ± 4%
84%e,f
88% ± 4%e
75% ± 5%
Comments
Freedom from reoperation,
93% for degenerative
disease/76% for rheumatic
disease (p < 0.01)
Increased complication/
failure rate with rheumatic
or multivalve disease
Failure risk directly related
to degree of disease
Chordal replacement for
anterior leaflet prolapse
David et al.d
David et al.c
Grossi et al.b
Study
Deloche et al.a
b
Deloche A, Jebara VA, Relland JYM, et al. Valve repair with Carpentier techniques: the second decade. J Thorac Cardiovasc Surg 1990;99:990–1002.
Grossi EA, Galloway AC, Miller JS, et al. Valve repair versus replacement for mitral insufficiency: when is a mechanical valve still indicated? J Thorac Cardiovasc Surg
1998;115:389–396.
c
Csapo K, Voith L, Szuk T, et al. Postinfarction left ventricular pseudoaneurysm. Clin Cardiol 1997;20:898–903.
d
David TE, Omran A, Armstrong, et al. Long-term results of mitral valve repair for myxomatous disease with and without chordal replacement with expanded
polytetrafluoroethylene. J Thorac Cardiovasc Surg 1998;115:1279–1286.
e
Eight-year data.
f
Freedom from late cardiac death.
g
Expanded polytetrafluoroethylene.
Source: Reprinted from Rosengart TK, de Bois W, Francalancia NA. Adult heart disease. In: Norton JA, Bollinger RR, Chang AE, et al, eds. Surgery: Basic Science and
Clinical Evidence. New York: Springer-Verlag, 2001, with permission.
a
184
1981–1992
Annuloplasty/
valvuloplasty
Chordal replacement
with e-PTFEg
725
1980–1996
Annuloplasty
n
206
Year of
enrollment
1972–1979
Primary repair
technique
Annuloplasty/
valvuloplasty
Table 15.4. Mitral valve repair.
280
A.J. Spotnitz
Valve replacement
Angina
DOE followed by
congestive heart failure
Syncope
Cardiomegaly; crescendodecrescendo midsystolic murmur, loudest
2nd right intercostal
space radiating to neck
CXR, ECG,
echocardiography
Left and right; left
ventriculogram, aortic
root injection, coronary
angiography age >40 or
family history CAD;
gradient >60 mm Hg;
valve area <1.0 cm2
If “asymptotic” close
follow (every 3 months)
Urgent surgery if
symptoms develop
Any symptomatic patient
Aortic stenosis
Congenital bicuspid
Rheumatic
Degenerative
Any symptomatic patient,
all patients ESD >55 mm,
EF <40%, decreasing EF
or increasing heart size
under treatment
Valve replacement, rare
valvuloplasty
If asymptotic and normal
LV, follow medically
(Procardia)
Cardiomegaly; waterhammer pulse;
decrescendo diastolic
murmur loudest 4th left
intercostal space
CXR, ECG,
echocardiography
Left and right; left
ventriculogram, aortic
root injection, coronary
angiography age >40 or
family history CAD; 1+
to 4+ regurgitation
Aortic insufficiency
Rheumatic, congenital,
endocarditis, connective
tissue disease (Marfan’s),
aortic dissection,
hypertension,
inflammatory disease
Indolent onset CHF
symptoms; decreased
exercise tolerance
Balloon commissurotomy,
commissurotomy (open) or
valve replacement
CXR, ECG,
echocardiography
Left and right; left
ventriculogram, coronary
angiography age >40 or
family history CAD;
simultaneous PCW and
LVEDP for mitral gradient;
valve area < 2 cm2
Coumadin and
antiarrhythmics for atrial
fibrillation, treat early
CHF
Class II if commissurotomy
likely
Class III or IV
Dyspnea on exertion, CHF,
atrial fibrillation,
embolization, hemoptysis
(late)
Possible RVH
Diastolic rumble, loudest
at apex
Mitral stenosis
Rheumatic, endocarditis,
pseudostenosis due to
myxoma
Valvuloplasty (may be
complex) or valve
replacement
CXR, ECG,
echocardiography
Left and right; left
ventriculogram, coronary
angiography age >40 or
family history CAD; 1+ to
4+ regurgitation on
ventriculogram, ventricular
and/or atrial enlargement
Coumadin and
antiarrhythmics for atrial
fibrillation, treat early
CHF
Class II if valvuloplasty
likely, all class III or IV,
ESD >55 mm regardless of
symptoms
Possible RVH
Holosystolic blowing
murmur loudest at apex,
radiating to axilla
CHF, atrial fibrillation,
embolization, right-sided
CHF, hepatomegaly
Mitral insufficiency
Rheumatic, ruptured chordae
tendinae, papillary muscle
dysfunction or rupture. LV
dilation, ischemic
cardiomyopathy
CAD, coronary artery disease; CHF, congestive heart failure; CXR, chest x-ray; DOE, dyspnea on exertion; ECG, electrocardiogram; EF, ejection fraction; ESD, end
systolic diameter; LVEDP, left ventricular end-diastolic pressure; PCW, pulmonary capillary wedge; RVH, right ventricular hypertrophy.
Operative
procedure
Operative
indications
Medical
management
Cardiac
catheterization
and findings
Diagnostic studies
Physical findings
Signs and
symptoms
Etiology
Table 15.5. Summary of diagnosis and treatment of valvular heart disease in the adult.
15. Heart Murmurs: Acquired Heart Disease
281
282
A.J. Spotnitz
of bacteremia. Patients with mechanical valves must be maintained
on proper levels of Coumadin to maintain the international normalized ratio (INR) at a proper range. The addition of aspirin in certain
patients also may be warranted. The risk of valve thrombosis or
embolization is a real potential for these patients, approaching 1% per
patient year. In addition, the risk of anticoagulation-associated death
or significant bleeding (requiring transfusion) is 1% to 2% per year.
Patients who have had tissue valve replacement or annuloplasty rings
inserted should receive anticoagulants for 3 months and can have it
discontinued after that time.
Summary
Valvular heart disease was one of the first problems addressed by
cardiac surgeons. Valve repair and replacement have become a
“routine” method of treatment for symptomatic patients, relieving
symptoms and prolonging life. Table 15.5 provides a summary of much
of what is discussed in this chapter.
Selected Readings
American Heart Association/American College of Cardiology. Consensus
Statement on Management of Patients with Valvular Heart Disease. Circulation 1998;98:1949–1984.
Auport MR, Sirinelli AL, Diermont FF, et al. The last generation of pericardial
valves in the aortic position: ten year follow-up in 589 patients. Ann
Thoracic Surg 1996;61:615–620.
Csapo K, Voith L, Szuk T, et al. Postinfarction left ventricular pseudoaneurysm.
Clin Cardiol 1997;20:898–903.
David TE, Omran A, Armstrong, et al. Long-term results of mitral valve repair
for myxomatous disease with and without chordal replacement with
expanded polytetrafluoroethylene. J Thorac Cardiovasc Surg 1998;115:
1279–1286.
Deloche A, Jebara VA, Relland JYM, et al. Valve repair with Carpentier techniques: the second decade. J Thorac Cardiovasc Surg 1990;99:990–1002.
Grossi EA, Galloway AC, Miller JS, et al. Valve repair versus replacement
for mitral insufficiency: when is a mechanical valve still indicated? J Thorac
Cardiovasc Surg 1998;115:389–396.
Komeda M, David TE. Surgical treatment of postinfarction false aneurysm of
the left ventricle. J Thorac Cardiovasc Surg 1993;106(60):1189–1191.
Lopez-Sendon J, Gonzalez A, Lopez de Sa E, et al. Diagnosis of subacute ventricular wall rupture after acute myocardial infarction: sensitivity and specificity of clinical, hemodynamic and echocardiographic criteria. J Am Coll
Cardiol 1992;19:1145–1153.
Purcaro A, Costantini C, Ciampani N, et al. Diagnostic criteria and management of subacute ventricular free wall rupture complicating myocardial
infarction. Am J Cardiol 1997;80:397–405.
Rosengart TK, de Bois W, Francalancia NA: Adult heart disease. In: Norton JA,
Bollinger RR, Chang AE, et al, eds. Surgery: Basic Science and Clinical
Evidence. New York: Springer-Verlag, 2001.
15. Heart Murmurs: Acquired Heart Disease
Schwarz CD, Penzengruber C, Ng CK, et al. Clinical presentation of rupture of
the left ventricular free wall after myocardial infarction: report of five cases
with successful surgical repair. Thorac Cardiovasc Surg 1996;44:71–75.
Society of Thoracic Surgeons National Adult Cardiac Surgery Database, 1999.
Voluntary registry of results from more than 500 participating cardiac
surgery programs nationwide. Circulation 1998;98:1949–1984.
Web Sites
American Heart Association: www.americanheart.org.
Society of Thoracic Surgeons: www.sts.org.
283

Similar documents