Heart Murmurs: Acquired Heart Disease 15

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

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.

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 attribut- able to acute changes in structural anatomy of the valve (endocardi- tis, 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 clas- sified 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 ante- rior 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 cm

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. Vol-

untary registry of results from more than 500 participating cardiac surgery programs

nationwide. Data available at www.sts.org.

266 A.J. Spotnitz

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 pro- gressive 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 cm

. 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 papil- lary muscle results in mitral insufficiency due to the loss of the teth- ering 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 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.)

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 signifi- cance. Next, it must be determined if a heart valve abnormality is, in fact, the cause of the murmur. Other causes do exist, such as congen- ital heart disease that was not recognized during childhood or an acquired ventricular defect following a myocardial infarction. The pres- ence 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.

Heart murmur Follow

CHF No CHF Normal

Echo, TEE

Enlarged LV Symptoms

ECG, CXR No

Afib Yes NSR

Depending on severity of symptoms admit or not

begin medical treatment

Admit Rate control Heparin + Coumadin Echo

Consider cardioversion if no thrombus Acute or

chronic anticoag

Echo/TEE

Enlarged Left ventricle

Normal

Medical treatment class II

Further evaluation Medical treatment Possible early surgery if mitral stenosis or mitral regurgitation Cardiac catheter

Elective surgery

Echo, TEE

Normal LV History Afib

Consider catheter or surgical treatment

Yes No or unsuccessful:

catheter

If symptoms persist

Catheter

OR Coumadin

Medical treatment Coumadin TEE

Normal AS Cath, OR AI Cath? OR MS Cath? OR

Medical treatment Follow

Enlarged LV

Catheter OR

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 stenosis

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.

Aortic Stenosis

Surgery involving the aortic valve is the second most common proce- dure 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 multi- factorial 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 three- leaflet valve. Patients who present in the fourth or fifth decade of life often have a congenital bicuspid aortic valve that becomes progres- sively 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 calci- fied, 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 cm

: 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 pres- sures can reach 300 mm Hg or more. Onset of one or all of these symp- toms 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 unex- plained 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 appropri- ately with diuretics and antianginal medications while assessment of the patient progresses. Care must be taken, however, to avoid exces- sive 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

factor in aortic stenosis, volume overload is the culprit in aortic insuf- ficiency. 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 com- pensation can be quite effective and result in a massively enlarged heart and progression of ventricular enlargement without significant symp- toms. The natural history of aortic insufficiency is less clear than that of aortic stenosis, and patients may survive many years with signifi- cant 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 pro- lapsing into the mitral annulus can mimic the signs of valvular steno- sis. 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 cm

and is related to increasing pres- sure 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 dilata- tion 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 present- ing sign. Medical therapy is directed to the treatment of congestive heart failure and atrial fibrillation while the diagnostic workup pro- gresses 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. Rup-

tured chordae tendinae or papillary muscle results in significant regur-

gitation, as may myocardial infarction affecting the ventricular wall at

the base of the papillary muscle. Myxomatous degeneration of the

270 A.J. Spotnitz

valve can result as a sequela of mitral valve prolapse. Significant ven- tricular dilation that affects the annulus of the valve can lead to pro- found 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 circu- lation. 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 tri- cuspid 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 myocar- dial 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 com- pensate 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.

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 implan- tation of a new valve to minimize the risk of prosthetic valve endo- carditis. 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

272 A.J. Spotnitz

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 con- firming 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 specif- ically 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 eval- uation 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 catheteriza-

tion 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 ven-

tricular chamber. Any gradient indicative of stenosis across the aortic

valve is measured. The gradient across the mitral valve is the differ-

ence between simultaneous measurements of pulmonary capillary

wedge pressure (the equivalent of left atrial pressure) and left ventric-

ular end-diastolic pressure. Across the aortic valve, a pullback reading is obtained on several occasions. The valve areas then can be calcu- lated using the Gorlin formula that relates the area of the valve to the pressure gradient across the valve and the cardiac output. Coro- nary 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 catheter- ization 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 coro- nary 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 main- tain 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, espe- cially 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

274 A.J. Spotnitz

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 indi- cations 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.

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 contraindica- tions 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 cm

or a gradient >60 mm Hg also should undergo valve replacement.

More recently, with the ability to follow patients closely with echocar- diography, surgery may be delayed until symptoms develop without increased risk to the patient as long as surgery occurs rapidly fol- lowing 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 ven- tricle 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 symp- tomatic patients and all patients with one of the following signs even in the absence of symptoms: increasing size of the heart, decreas- ing 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 treat- ment 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.

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 suc- cessfully in the late 1940s several years before the first successful use of the heart lung machine (by Gibbon

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 con- dition 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 symp- toms. All class III and IV patients should be considered for surgery.

On the other hand, increasing ventricular chamber size or end sys- tolic 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 opera- tive 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 main- tain 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.

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 pros- thetic valves available: mechanical and tissue. The advantages of the former include longer durability and perhaps lower residual gradi- ent size for size compared to stented tissue valves. The disadvantage of the mechanical valve is the requirement for lifelong anticoagula- tion 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 implanta- tion) 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 fre- quently 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 anti- coagulation 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

278 A.J. Spotnitz

T able 15.2. Selected series of aortic valve replacement. Operative Freedom from Y ears of mortality Actuarial valve-related Freedom from V alve type enrollment n (%) survival complications reoperation Source Mechanical St. Jude 1982–1991 61 1 5.4 5 y r, 78% — — Fernandez

St. Jude 1979–1990 254 3.9 5 y r, 80% ± 3% 10 yr , 35% ± 8% 10 yr , 92% ± 2% Kratz

10 yr , 47% ± 9% Carbomedics 1989–1994 349 3.4 5 y r, 77% ± 4% 5 y r, 69% ± 4% 5 y r, 96% ± 1% Bernal

Bioprosthetic Porcine 1979–1995 578 5 1 0 y r, 64% ± 22% — 1 5 y r, 55% ± 4% Jamieson (Carpentier -Edwards) 15 yr , 39% ± 3% Porcine 1982–1990 376 4 8 yr , 79% ± 3% 8 y r, 93% ± 3%

8 y r, 91% ± 4% David

(Hancock) Bovine pericardial 1984–1993 589 2.3 10 yr , 71% ± 7% 10 yr , 84% ± 6% 10 yr , 76% ± 2% Auport

(Carpentier -Edwards) 15 yr , 53% ± 4%

Pur car o A, Costantini C, Ciampani N, et al. Diagnostic criteria and management of subacute ventricular fr ee wall r uptur e compli cating myocar dial infar ction. Am J Car diol 1997;80:397–405.

Y eo TC, Malouf JF , Oh JK, et al. Clinical pr ofile and outcome in 52 patients with car diac pseudoaneurysm. Ann Intern Med 1998;12 8:299–305.

Schwarz CD, Punzengr uber C, Ng CK, et al. Clinical pr esentation of r uptur e of the left ventricular fr ee wall after myocar dial i nfar ction: r eport of five cases with suc- cessful sur gical r epair . Thorac Car diovasc Sur g 1996;44:71–75.

Fr eedom fr om thr omboembolism.

Komeda M, David TE. Sur gical tr eatment of postinfar ction false aneurysm of the left ventricle. J Thorac Car diovasc Sur g 1993;10 6(6):1 189–1 191.

Auport MR, Sirinelli AL, Diermont FF , et al. The last generation of pericar dial valves in the aortic position: ten year follow- up in 589 patients. Ann Thorac Sur g 1996;61:615–620. Sour ce: Reprinted fr om Rosengart TK, de Bois W , Francalancia NA. Adult heart disease. In: Norton JA, Bollinger RR, Chang AE, et al, eds . Sur gery: Basic Science and Clinical Evidence. New Y ork: Springer -V erlag, 2001, with permission.

T able 15.3. Selected series of mitral valve replacement. Operative Freedom from Y ears of mortality Actuarial valve-related Freedom from V alve type enrollment n (%) survival complications reoperation Source Mechanical St. Jude 1980–1996 514 7.2 8 y r, 89% — — Grossi

St. Jude 1979–1990 397 3.5 10 yr , 73% ± 6% 3.7% (pt-yr) — Jegaden

Carbomedics 1989–1994 330 6.9 5 y r, 77% ± 4% 10 yr , 69% ± 4% — Bernal

Bioprosthetic Porcine 1975–1995 512 9 1 0 y r, 52% ± 2% — 1 5 y r, 20% ± 4% Jamieson (Carpentier -Edwards) 15 yr , 24% ± 3% Porcine 1982–1990 195 6 8 yr , 68% ± 4%

8 y r, 83% ± 5%

8 y r, 92% ± 5% David

(Hancock)

Gr ossi EA, Galloway AC, Miller JS, et al. V alve r epair versus r eplacement for mitral insuf ficiency: when is a mechanical valve s till indicated? J Thorac Car diovasc Sur g 1998;1 15:389–396.

Lopez-Sendon J, Gonzalez A, Lopez de Sa E, et al. Diagnosis of subacute ventricular wall r uptur e after acute myocar dial infar ct ion: sensitivity and specificity of clinical, hemodynamic and echocar diographic criteria. J Am Coll Car diol 1992;19:1 145–1 153.

Schwarz CD, Punzengr uber C, Ng CK, et al. Clinical pr esentation of r uptur e of the left ventricular fr ee wall after myocar dial i nfar ction: r eport of five cases with suc- cessful sur gical r epair . Thorac Car diovasc Sur g 1996;44:71–75.

Fr eedom fr om late car diac death.

Fr eedom fr om thr omboembolic complications.

Csapo K, V oith L, Szuk T , et al. Postinfar ction left ventricular pseudoaneurysm. Clin Car diol 1997;20:898–903. Sour ce: Reprinted fr om Rosengart TK, de Bois W , Francalancia NA. Adult heart disease. In: Norton JA, Bollinger RR, Chang AE, et al, eds . Sur gery: Basic Science and Clinical Evidence. New Y ork: Springer -V erlag, 2001, with permission.

280 A.J. Spotnitz

T able 15.4. Mitral valve repair . Operative T en-year Primary repair Y ear of mortality actuarial Freedom from technique enrollment n (%) survival reoperation Comments Study Annuloplasty/ 1972–1979 206 5.5 72% ± 4% 15 yr , 87% ± 3% Freedom from reoperation, Deloche et al.

valvuloplasty 93% for degenerative disease/76% for rheumatic disease ( p < 0.01) Annuloplasty 1980–1996 725 5.4 84%

76%

Increased complication/ Grossi et al.

failure rate with rheumatic or multivalve disease Annuloplasty/ 1981–1992 184 0.5 88% ± 4%

95% ± 2% Failure risk directly related David et al.

valvuloplasty to degree of disease Chordal replacement 1981–1995 324 0.6 75% ± 5% 96% ± 1% Chordal replacement for David et al.

with e-PTFE

anterior leaflet prolapse

Deloche A, Jebara V A, Relland JYM, et al. V alve r epair with Carpentier techniques: the second decade. J Thorac Car diovasc Sur g 1990;99:990–1002.

Gr ossi EA, Galloway AC, Miller JS, et al. V alve r epair versus r eplacement for mitral insuf ficiency: when is a mechanical valve s till indicated? J Thorac Car diovasc Sur g 1998;1 15:389–396.

Csapo K, V oith L, Szuk T , et al. Postinfar ction left ventricular pseudoaneurysm. Clin Car diol 1997;20:898–903.

David TE, Omran A, Armstr ong, et al. Long-term r esults of mitral valve r epair for myxomatous disease with and without chor dal r eplacement with expanded polytetrafluor oethylene. J Thorac Car diovasc Sur g 1998;1 15:1279–1286.

Eight-year data.

Fr eedom fr om late car diac death.

Expanded polytetrafluor oethylene. Sour ce: Reprinted fr om Rosengart TK, de Bois W , Francalancia NA. Adult heart disease. In: Norton JA, Bollinger RR, Chang AE, et al, eds . Sur gery: Basic Science and Clinical Evidence. New Y ork: Springer -V erlag, 2001, with permission.

T able 15.5. Summary of diagnosis and treatment of valvular heart disease in the adult. Aortic stenosis Aortic insuf ficiency Mitral stenosis M itral insuf ficiency Etiology Congenital bicuspid Rheumatic, congenital, Rheumatic, endocarditis, Rheumatic, ruptured chordae Rheumatic endocarditis, connective pseudostenosis due to tendinae, papillary muscle Degenerative tissue disease (Marfan’ s), myxoma dysfunction or rupture. L V aortic dissection, dilation, ischemic hypertension, cardiomyopathy inflammatory disease Signs and Angina Indolent onset CHF Dyspnea on exertion, CHF , CHF , atrial fibrillation, symptoms DOE followed by symptoms; decreased atrial fibrillation, embolization, right-sided congestive heart failure exercise tolerance embolization, hemoptysis CHF , hepatomegaly Syncope (late) Physical findings Cardiomegaly; crescendo- Cardiomegaly; water - Possible R V H Possible R V H decrescendo mid- hammer pulse; Diastolic rumble, loudest Holosystolic blowing systolic murmur , loudest decrescendo diastolic at apex murmur loudest at apex, 2nd right intercostal murmur loudest 4th left radiating to axilla space radiating to neck intercostal space Diagnostic studies CXR, ECG, CXR, ECG, CXR, ECG, CXR, ECG, echocardiography echocardiography echocardiography echocardiography Cardiac Left and right; left Left and right; left Left and right; left Left and right; left catheterization ventriculogram, aortic ventriculogram, aortic ventriculogram, coronary ventriculogram, coronary and findings root injection, coronary root injection, coronary angiography age >40 or angiography age >40 or angiography age >40 or angiography age >40 or family history CAD; family history CAD; 1 + to family history CAD; family history CAD; 1 + simultaneous PCW and 4+ regurgitation on gradient >60 mm Hg; to 4+ regurgitation L VEDP for mitral gradient; ventriculogram, ventricular valve area <1.0 cm

valve area < 2c m

and/or atrial enlargement Medical If “asymptotic” close If asymptotic and normal Coumadin and Coumadin and management follow (every 3 months) L V , follow medically antiarrhythmics for atrial antiarrhythmics for atrial Urgent surgery if (Procardia) fibrillation, treat early fibrillation, treat early symptoms develop CHF CHF Operative Any symptomatic patient Any symptomatic patient, Class II if commissurotomy Class II if valvuloplasty indications all patients ESD >55 mm, likely likely , all class III or IV , EF <40%, decreasing EF Class III or IV ESD >55 mm regardless of or increasing heart size symptoms under treatment Operative V alve replacement V alve replacement, rare Balloon commissurotomy , V alvuloplasty (may be procedure valvuloplasty commissurotomy (open) or complex) or valve valve replacement replacement CAD, cor onary artery disease; CHF , congestive heart failur e; CXR, chest x-ray; DOE, dyspnea on exertion; ECG, electr ocar diogram ; EF , ejection fraction; ESD, end systolic diameter; L VEDP , left ventricular end-diastolic pr essur e; PCW , pulmonary capillary wedge; R VH, right ventricular hyper tr ophy .

of bacteremia. Patients with mechanical valves must be maintained on proper levels of Coumadin to maintain the international normal- ized 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. Circula- tion 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 tech- niques: 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 ven- tricular wall rupture after acute myocardial infarction: sensitivity and speci- ficity 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 manage- ment 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.

282 A.J. Spotnitz

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.