the right atrium via a transseptal approach and inflated across the diseased valve.36 This has become the

standard of care for select MS patients.17 Scoring systems have been developed to aid in patient

selection. Leaflet thickness, pliability, degree of calcification of the valves and the subvalvular

apparatus are central in these scoring systems with lower scores (e.g., <8 in the Wilkins score)

correlating with improved outcomes.37 Contraindications include the presence of a left atrial thrombus,

moderate to severe MR, heavy annular or leaflet calcification, and severe subvalvular distortion.

Procedural mortality of PBMV is 1% to 2% in large series. Rare risks of the procedure include MR,

iatrogenic creation of an atrial septal defect, perforation of the left ventricle, embolic events, and

myocardial infarction.38–42

Success of PBMV can be measured by the increase in mitral valve area (MVA), restenosis at long-term

follow-up and event-free survival (death, repeat procedure or surgery, NYHA III or IV). Overall,

significant (MVA ≥1.5 cm2) increase in MVA are obtained in over 80% of patients

43 with freedom from

restenosis and event-free survival at 10 years at 70% and 80%, respectively.44,45

Open Mitral Commissurotomy

OMC permits direct inspection of the MV apparatus and allows debridement of calcium deposits,

division of the commissures, and splitting of fused chordae tendineae under direct vision. Additionally,

the left atrial appendage can be surgically oversewn from within the left atrium, reducing the risk of

postoperative embolization. The contraindications to OMC are similar to those of PBMV.

The operative mortality of OMC is less than 2%,46,47 and complication rates are similar to those of

PBMV.48,49 Short- and long-term hemodynamic results and symptomatic results are similar between

PBMV and OMC in younger patients with less severe valve pathology (lower Wilkins scores).48 More

favorable results are seen with OMC in older patients with subvalvular fusion, leaflet calcification, and

less valve flexibility (higher Wilkins scores).49

Mitral Valve Replacement

MV replacement is necessary in symptomatic patients with moderate to severe MS when there is a

significant amount of calcification or subvalvular fusion, since PBMV and OMC are less likely to be

successful. MV replacement is also necessary in symptomatic patients with moderate to severe MS and

concomitant moderate to severe MR.17 The choice of valve prosthesis for MV replacement is determined

in a similar manner as choosing the prosthesis for AVR. Biologic prostheses are used in the elderly and

those in whom long-term warfarin is contraindicated. Regardless of the prosthesis used, it is well

established that preservation of the papillary muscle attachments to the annulus plays an important role

in the maintenance of LV function.50–54 The operative mortality of MV replacement is 5% to 6% and

freedom from reoperation at 15 years is 50% to 75%.55

MITRAL REGURGITATION

Prevalence and Etiology

8 Since competency of the MV is dependent on the entire MV apparatus, dysfunction of any one of the

components can lead to mitral regurgitation (MR). The most common overall cause of MR is

degenerative MV disease. Other causes of MR include rheumatic valve disease, endocarditis, certain

drugs, and collagen vascular disease. In some cases, functional MR develops as a result of dilation of the

LV from cardiomyopathy or severe ischemic heart disease. Finally, rupture of a papillary muscle from

myocardial infarction or endocarditis, or rupture of a chord can lead to the onset of acute, severe MR.

Pathophysiology

MR is caused by deficient coaptation of the MV leaflets, which results in blood flow from the left

ventricle into the left atrium during systole. Regardless of etiology, the pathophysiology of chronic MR

is similar. MR results in gradual enlargement of the left atrium as a result of volume overload. Decrease

in the functional stroke volume causes an increase in LV size with a subsequent decrease in LV function.

On the other hand, the pathologic process that takes place in acute MR is quite different. Sudden

volume overload results in an increase in LV preload and a decrease in forward stroke volume, since

compensatory LV eccentric hypertrophy has not had time to develop. Similarly, acute volume overload

of the left atrium results in an increase in left atrial pressure and pulmonary congestion.

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Diagnosis

Symptoms

Symptoms of chronic MR include fatigue, dyspnea on exertion, and shortness of breath. More advanced

stages of disease are characterized by the development of heart failure. Acute, severe MR is

characterized by acute pulmonary edema and cardiogenic shock.

Signs

The point of maximum impulse is typically laterally displaced. The classic auscultatory findings of MR

are best heard at the apex and include a high-pitched, blowing, holosystolic murmur radiating to the

axilla; a diminished S1

; and an S3

.

Imaging

Echocardiography is used to assess the severity of MR, morphology of the MV, and size and function of

the LV and atrium. Assessment of the severity of MR is determined by the jet area/left atrial area,

regurgitant volume, regurgitant fraction, and regurgitant orifice area (Table 82-4). Additionally,

magnetic resonance imaging (MRI) allows accurate measurements of the severity of regurgitation and

quantification of regurgitant volumes, along with assessment of LV size and function.

Natural History

Patients with mild to moderate MR usually remain asymptomatic with little or no hemodynamic

compromise for many years. In patients with severe MR caused by flail leaflets, mortality is 6% to 7%

per year, and 90% of patients die or require an MV operation within 10 years.56

Treatment

Given most recent guidelines, surgery should be performed early, before signs of LV function

deterioration, and even asymptomatic patients with severe MR should be offered surgery if there is a

high probability of successful repair and low mortality risk.57,58 MV repair is preferred surgical therapy

for most patients with MR, since it preserves the native valve and avoids the need for anticoagulation,

which is required in the majority of patients who undergo valve replacement.59 Preservation of the MV

and chordae preserves LV function and improves survival. Success rates of MV repair depend on the

etiology of regurgitation. Durable MV repair can be accomplished in more than 90% of patients with

degenerative MV disease. Standard techniques for MV repair include resection of the prolapsed portion

of the MV leaflet, leaflet reconstruction, and insertion of an annuloplasty ring (Fig. 82-8).

DIAGNOSIS

Table 82-4 Classification of Mitral Regurgitation Severity

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Figure 82-8. Schematic diagram of posterior mitral valve repair and insertion of annuloplasty ring.

Mortality of isolated MV repair is less than 1%, with greater than 90% freedom from reoperation at

10 years. Functional MR is usually repaired with the use of an undersized annuloplasty ring to reduce

the diameter of the mitral annulus and restore valve competency. MV repair is also the preferred

surgical therapy in patients with MV endocarditis. Resection of all infected valve tissue is the mainstay

of valvular reconstruction in patients with endocarditis. This is followed by leaflet reconstruction,

commonly with the use of an autologous pericardial patch and an annuloplasty (Fig. 82-9).

MV repair is indicated for patients in whom adequate MV repair cannot be accomplished. Mechanical

valve replacements are indicated in patients younger than 65 years of age and stented bioprostheses are

indicated in the elderly.

Isolated MV repair and replacement are traditionally performed through a full sternotomy. Minimally

invasive approaches, which include partial upper and lower sternotomy and right mini anterolateral

thoracotomy, decrease the degree of surgical trauma and blood loss and allow faster recovery with less

postoperative pain, sternal wound complications, and better cosmetic result.60–62 Robotically assisted

MV repair, which is performed through small port-like incisions, is the least invasive surgical approach

that eliminates the need for sternotomy or thoracotomy, and as such provides faster postoperative

recovery in hospital as well as after discharge (Fig. 82-10).63–66

Figure 82-9. Schematic diagram of mitral valve repair with autologous pericardial patch and insertion of an annuloplasty ring.

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Figure 82-10. Surgical approaches to the mitral valve. A: Full sternotomy. B: Partial sternotomy. C: Limited right anterolateral

mini-thoracotomy. D: Robotically assisted.

In patients with severe MR who are determined to be at prohibitive risk for surgery given existing

comorbidities alternative treatment option is percutaneous MV repair. MitraClip system is a

percutaneously delivered device that offers similar mortality and symptomatic improvement. However,

due to higher rate of MR requiring repeat procedures, and less improvement in LV dimensions as

compared to surgery, the latter remains the standard of care for treatment of MR among eligible

patients. 67

TRICUSPID VALVE DISEASE

TV disease is less common than AV and MV disease. Tricuspid regurgitation (TR), the most common

form of TV dysfunction, can occur with anatomically normal or abnormal valves. Functional TR is

caused by right ventricular dilation and consequent leaflet malcoaptation in an otherwise anatomically

normal valve. Right ventricular enlargement occurs in patients with pulmonary hypertension, most

commonly caused by longstanding MV dysfunction. TV endocarditis most commonly occurs in

intravenous drug users and causes TR by destruction of the leaflets.

Echocardiography is used to assess the degree of TR, anatomy of the TV, right ventricular function,

and pulmonary pressures.

Mild to moderate degrees of TR often resolve spontaneously once the MV disease causing the

pulmonary hypertension is corrected. Severe functional TR is corrected by reduction in the diameter of

the tricuspid annulus, most commonly using an annuloplasty ring. Severe endocarditis requires complete

resection of infected valve tissue, followed by TV replacement with a bioprosthesis. In active drug

users, insertion of a valve prosthesis may be delayed by several months to decrease the risk of recurrent

endocarditis.

Valve Prostheses

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Development of valve prostheses has transformed the treatment of valvular heart disease. Numerous

types of prostheses are currently available for clinical use, and they differ in design, biocompatibility,

and hemodynamic characteristics. They are broadly classified into mechanical and bioprosthetic.

Contemporary mechanical valves are bileaflet valves composed of carbon material that is mounted on

a sewing ring (Fig. 82-5). Mechanical valve prostheses are durable and have excellent hemodynamic

performance. Patients with mechanical prostheses require lifelong anticoagulation with warfarin, which

results in a 1% to 3% risk of bleeding per year. These characteristics make mechanical valves the

prosthesis of choice for younger patients with no contraindications to long-term anticoagulation.17

Biologic prostheses are composed of valve leaflets created from bovine pericardium or porcine valve

leaflets mounted on a sewing ring (Fig. 82-6). Biologic prostheses have slightly inferior hemodynamic

characteristics when compared with mechanical prostheses and a limited durability of 10 to 15 years.

However, bioprostheses are not thrombogenic and therefore do not require anticoagulation.

Bioprostheses are generally indicated in older individuals and younger patients who have

contraindications to long-term anticoagulation.

There has been an increased use of bioprostheses in younger individuals due to recent improvements

in design of the prostheses, expected increases in valve durability, and decreased risk of reoperations.

Aortic homografts are cryopreserved allografts that are composed of AVs and ascending aortas.

Homografts are not thrombogenic, have excellent hemodynamic characteristics, and have high

resistance to infection. Homografts are indicated in patients with AV endocarditis. Their use for primary

AVR is limited due to the complexity of the operation and limited durability (10 years).

CARDIAC TUMORS

Cardiac tumors can be located in the epicardium, myocardium, endocardium, or any combination of the

three. In general, tumors that involve the parietal pericardium are not classified as cardiac tumors.

8 Tumors of the heart are classified as either primary or secondary. Primary tumors arise in the heart

and are either benign or malignant. Secondary tumors are metastases from primary tumors arising

elsewhere and hence are always malignant. Primary tumors are rare, with an autopsy incidence of less

than 0.1%.68 Secondary tumors are observed more commonly, with a postmortem incidence of about

1%.69

Cardiac tumors present with variable symptoms. Symptoms are frequently determined by the

intracardiac location of the tumor. Intracavitary tumors can obstruct blood flow, causing signs and

symptoms that mimic those of valvular heart disease. Intracavitary tumors can also cause embolic

events, resulting in symptoms related to the site of embolization. Intramyocardial tumors can trigger

cardiac rhythm disturbances, including sudden death.70 Cardiac tumors can also cause systemic

symptoms mimicking collagen vascular disease, malignancy, or infective endocarditis.70

BENIGN PRIMARY CARDIAC TUMORS

Myxomas

Definition, Incidence, and Prevalence

Myxomas are the most common primary cardiac tumors. They are benign. Although myxomas have

been reported in both genders and in all age groups, they most often occur in women in the third to

sixth decades of life. Myxomas are usually sporadic, but at least 7% occur as part of an autosomal

dominant syndrome.

Morphology

Arising from the endocardium, myxomas usually extend into a cardiac chamber. They are generally

polypoid, pedunculated lesions with a smooth surface that may be covered with thrombus (Fig. 82-11A).

The tumors range in size from 1 to 15 cm, but are most commonly about 5 cm.71–74 Myxomas are

thought to arise from pluripotent mesenchymal cells. Histologically, myxomas consist of a matrix of

acid mucopolysaccharide (Fig. 82-11B).68 Myxomas most commonly occur in the atria. Approximately

75% arise in the left atrium, and 15% to 20% arise in the right atrium.73 The remainder of myxomas are

located in the ventricles.

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Figure 82-11. Left atrial myxoma. A: Gross photograph showing large pedunculated lesion arising from the left atrium and

extending into the mitral valve orifice. B: Microscopic appearance, with abundant acid mucopolysaccharide, scattered collections of

myxoma cells, and abnormal vascular formations (arrow). (Reproduced with permission from Kumar V, Abbas AK, Fausto N.

Robbins and Cotran Pathologic Basis of Disease. 7th ed. Philadelphia, PA: Elsevier; 2005.)

Clinical Characteristics

Many patients with myxomas are asymptomatic. The myxoma may be detected by routine screening

echocardiography performed for other indications. Asymptomatic myxomas should be excised in order

to prevent emboli, valvular dysfunction, or constitutional symptoms.

Patients with myxomas can have a variety of symptoms. In the sporadic form, classic findings include

emboli, congestive heart failure caused by obstruction of cardiac blood flow, and constitutional

symptoms. These sequelae are related to the location, size, and mobility of the tumor. Because most

myxomas arise in the left atrium, systemic embolization is common, occurring in 30% to 50% of

cases.75–77

Myxomas also can display signs and symptoms related to cardiac obstruction. Typically, the findings

are related to the tumor’s ability to impede filling of the ventricles; in such instances, signs and

symptoms may mimic those of mitral or TV stenosis. Constitutional symptoms include fever, malaise,

rash, weight loss, and myalgia.

Diagnosis

Echocardiography is the imaging modality of choice for diagnosis of myxomas. In cases of diagnostic

uncertainty, MRI and computed tomography (CT) may be helpful. Final diagnosis is confirmed by

pathologic examination.

Management

Surgical resection is the mainstay of treatment. Great care must be taken to minimize manipulation of

the heart before cross-clamping the aorta to reduce the risk of intraoperative tumor embolization. A

variety of approaches are available for resection of left atrial tumors. In the absence of other cardiac

disease, a minimally invasive or robotically assisted operation can be employed to speed postoperative

recovery. The tumor is resected en bloc. Tumors that arise from a relatively well-defined pedicle can be

excised without full-thickness excision of a button of atrial wall. The results of surgical excision are

good with a low risk of morbidity and mortality (0% to 3%).78–80 A variety of approaches are available

for resection of left atrial tumors. In the absence of other cardiac disease, a minimally invasive

including robotically assisted operation can be employed due to superior postoperative recovery and

patient satisfaction, with equal safety and effectiveness.81–83

Other Benign Primary Tumors

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Rhabdomyoma

Rhabdomyoma is the most common cardiac tumor in children and the second most common benign

cardiac tumor overall.73 Most occur in children younger than 1 year of age. Rhabdomyoma is a benign

tumor composed of cardiac myocytes. About one-half of patients with rhabdomyoma have tuberous

sclerosis, and about one-half of patients with tuberous sclerosis develop rhabdomyomas.84 These tumors

occur sporadically or in conjunction with other rare congenital heart malformations.

Rhabdomyomas usually are found deep in the myocardium; they may extend into the cardiac

chambers. They are of variable size, ranging from 1 mm to several centimeters. Most rhabdomyomas

are multicentric and involve both ventricles. Because of their morphologic appearance and multicentric

nature, rhabdomyomas are classified as hamartomas rather than as true tumors.85 Pathologically, they

are distinguishable from the surrounding myocardium by their firm, gray, nodular characteristics.86

Most children with rhabdomyomas display cardiac arrhythmias or obstructive symptoms in the first

few days or weeks of life. Rhabdomyomas causing significant intracardiac obstruction to blood flow can

result in death within 24 hours of birth; patients with less severe disease may be asymptomatic for

years. The diagnosis is usually made by echocardiography. One of the curiosities of this tumor is the

well-documented tendency for these tumors to regress.87,88

In most cases these tumors are not resected. Surgical resection is reserved for masses that cause

significant cardiac obstruction.89,90 Given the multicentricity of the lesions and their limited growth

potential, the operative approach is conservative debulking, with the goal being relief of outflow

obstruction with preservation of electrical conduction and myocardial and valvular function.

Lipomas

Lipomas are encapsulated masses of adipose tissue that usually arise from the myocardium or

pericardium.73 They are usually small but can grow to be massive. Lipomas involving the pericardium

may be mistaken for pericardial cysts and may be associated with pericardial effusions. Although most

of these tumors are identified after death, they can be diagnosed by echocardiography and MRI. Most

cardiac lipomas can be observed. However, lipomas causing obstructive symptoms or arrhythmias

should be resected.

Papillary Fibroelastoma

Papillary fibroelastomas are the most common tumors affecting cardiac valves.91,92 They usually involve

the valves of the left side of the heart, and typically occur in adult patients.93 Although papillary

fibroelastomas usually are asymptomatic, when symptoms occur, they are most frequently related to

embolization. The tumors are identified by echocardiography. Surgical excision is advised, even in

asymptomatic patients.91,94,95 When resection is performed, a minimally invasive surgical approach is

generally possible.

Malignant Primary Cardiac Tumors

Angiosarcoma

Most malignant cardiac tumors are metastases from other malignancies.74 Almost all primary malignant

tumors of the heart are sarcomas

96; angiosarcoma is the most common malignant primary cardiac

tumor.73 Angiosarcomas are usually solitary, large bulky masses that originate in the right atrium (Fig.

82-12). They may extend into the right atrial cavity, causing valvular obstruction, right-sided heart

failure, or hemorrhagic pericardial effusion with tamponade.96 Most of these tumors metastasize, most

commonly to the lung, liver, or brain.97 Angiosarcomas are very aggressive, and survival after diagnosis

ranges from 3 to 15 months.85 Given their rapid growth and poor prognosis, surgical resection is rarely

successful.

Rhabdomyosarcoma

Rhabdomyosarcoma is the second most common cardiac sarcoma. Like angiosarcoma, it is more

common in men.98–100 Unlike angiosarcoma, rhabdomyosarcoma does not have a predilection for a

particular cardiac chamber.73 It may occur at multiple sites and extend into the pericardium. Patients

may have cardiac obstructive or constitutional symptoms. Prognosis is poor, and surgical resection is

usually ineffective.

Secondary Cardiac Tumors: Metastases to the Heart

Metastatic tumors to the heart, or secondary tumors, are much more common than are primary cardiac

2380

tumors. Secondary tumors are usually carcinomas rather than sarcomas because of the relative

frequency of these cancers.96 Hematogenous spread is the most common mode of metastasis, but

lymphatic spread and direct extension also occur.

Figure 82-12. Gross photograph of angiosarcoma of the right ventricle. (Reproduced with permission from Kumar V, Abbas AK,

Fausto N. Robbins and Cotran Pathologic Basis of Disease. 7th ed. Philadelphia, PA: Elsevier; 2005.)

Symptoms occur most commonly in patients with pericardial metastases rather than intramural or

intracavitary involvement. The symptoms associated with metastases are congestive heart failure and

arrhythmias. Metastases to the heart should be suspected in patients with known neoplasms who

develop congestive heart failure.

Carcinoma of the lung and breast may directly invade the parietal and visceral pericardium, causing

myocardial restriction and pericardial effusion.96 Melanoma commonly metastasizes to the myocardium,

as do leukemia and lymphoma. The treatment of metastatic tumors depends on the tumor type and

symptoms. Given the late stage at which cardiac metastases occur and the poor prognosis, few of these

patients are candidates for cardiac surgical intervention. Lymphoma and leukemia may respond to

chemotherapy or radiotherapy. Symptomatic malignant pericardial effusions may be drained by creation

of a pericardial window, temporarily relieving symptoms.

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3. Marzilli M, Sabbah HN, Stein PD. Mitral regurgitation in ventricular premature contractions. The

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