Figure 82-6. St. Jude Medical Epic Valve.

Percutaneous Balloon Aortic Valvotomy

PBAV is a procedure in which a balloon is placed across a stenotic AV and inflated in order to decrease

the degree of valve narrowing. This procedure is a valuable tool for treatment of AS in children and

young adults. Rapid development of restenosis and clinical deterioration limits its application in the

treatment of adults to those with severe AS who are not candidates for conventional surgical or

transcatheter AVR.

AORTIC REGURGITATION

Prevalence and Etiology

5 AR results from the improper coaptation of the AV leaflets due to either intrinsic leaflet abnormalities

or aortic root distortion. The most common causes of AR include bicuspid valve disease, rheumatic

fever, and endocarditis. Regurgitant bicuspid AVs are often partly calcified, which results in limited

opening and closing of the valve and a mixture of AR and AS. Rheumatic fever causes inflammation and

fibrosis of the leaflets, while endocarditis causes destruction of leaflets. In addition, AR can occur as a

secondary phenomenon of aortic root enlargement due to Marfan syndrome, anuloaortic ectasia, or

aortic dissection. Most of these causes produce chronic AR with a slow increase in LV size. Some lesions,

in particular acute aortic dissection and endocarditis, cause acute AR with a sudden decrease in cardiac

output.

Pathophysiology

In patients with AR, inappropriate coaptation of the aortic leaflets causes diastolic reflux of blood from

the aorta into the LV with a consequent increase in LV end-diastolic volume and pressure. In chronic AR,

compensatory mechanisms of the LV result in dilation and hypertrophy. LV hypertrophy and dilation

ultimately result in a decrease in LV function and heart failure.

Diagnosis

Symptoms

Chronic AR is usually well tolerated and patients with even severe AR often remain asymptomatic for

years. Initial symptoms of severe AR include fatigue, shortness of breath, and dyspnea on exertion.

Advanced AR is marked by the onset of congestive heart failure, syncope, and angina. Acute onset of

severe AR, such as in cases of aortic dissection or endocarditis-induced valve destruction, causes a

sudden increase in LV end-diastolic volume and pressure with subsequent cardiogenic shock and

pulmonary edema.

Signs

Lateral displacement of the point of maximum impulse is seen in chronic AR due to LV dilation and

hypertrophy. The classic auscultatory findings of AR are best heard at the right sternal border of the

second intercostal space and include a high-pitched, blowing holodiastolic decrescendo murmur; an S3

heart sound; and a systolic ejection murmur.

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Figure 82-7. Schematic diagram of percutaneous aortic valve replacement. A: Balloon valvuloplasty. B: Balloon catheter with valve

in the native diseased valve. C: Balloon inflation to secure the valve. D: Valve in place.

DIAGNOSIS

Table 82-2 Classification of Aortic Regurgitation Severity

Additionally, the widened pulse pressure leads to a number of interesting findings, such as bounding

pulses (water-hammer pulse), Quincke pulse (pulse in fingernail bed), De Musset sign (rhythmic

bobbing of the head), Duroziez sign (systolic and diastolic murmurs heard over the femoral artery when

it is gradually compressed), and Müller sign (pulsations of the uvula).16

Imaging

Echocardiography represents the diagnostic “gold standard” for patients with AR. It allows assessment

of the valvular and aortic anatomy, the severity of regurgitation, and the size and function of the left

ventricle. Assessment of the severity of AR is determined by color Doppler jet width, regurgitant

volume, regurgitant fraction, and regurgitant orifice area (Table 82-2). The role of coronary

angiography is reduced to the preoperative diagnosis of coronary artery disease.

Natural History

The natural history of AR is strongly dependent on the presence of symptoms and LV dysfunction at the

time of presentation. Asymptomatic patients with normal LV function develop symptoms and/or LV

dysfunction at 6% per year. Asymptomatic patients with LV dysfunction at presentation develop cardiac

symptoms at 25% per year. Finally, the mortality rate of symptomatic patients is 10% per year.17

Treatment

Management of patients with AR depends on the severity of symptoms and the size and function of the

left ventricle. Asymptomatic patients with chronic severe AR and preserved LV size and function are

treated with vasodilator medical therapy, which reduces afterload and improves forward flow.

Surgery is indicated in symptomatic patients with chronic severe AR and in asymptomatic patients

with severe AR and evidence of LV dilation (end-systolic LV diameter >55 mm) or dysfunction

(ejection fraction <50%). Additionally, acute severe AR with consequent pulmonary edema and shock

caused by endocarditis or aortic dissection is a surgical emergency.

AVR should be performed before irreversible changes in LV function occur. Mechanical valves are

indicated for patients younger than 65 years of age. Stented bioprostheses are used for AVR in patients

older than 65 and in younger patients with contraindications to long-term anticoagulation. AV repair

can be performed in patients with severe AR caused by bicuspid valve disease or connective tissue

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disorders. Traditionally, patients with proximal aortic root pathology, including dissection and

aneurysms with secondary AR underwent aortic root replacement with a mechanical valve. This was

done regardless whether or not their native valve was diseased. The valve sparing root replacement

(David procedure) has been shown to have similar morbidity and mortality with minimal risk of

thromboembolism or endocarditis. Additionally, it precludes the need for anticoagulation and has an

acceptably low reoperation rate. This makes it ideal for young patients, especially those with connective

tissue disorders.27–30

MITRAL STENOSIS

Prevalence and Etiology

6 Mitral stenosis (MS) is predominantly caused by rheumatic fever. The steady rate of decline of

rheumatic fever in developed countries has resulted in a similar decline in the prevalence of MS. Other

far less common causes of MS include severe annular and leaflet calcification, congenital malformations,

malignant carcinoid, left atrial myxoma, left atrial thrombus, and endocarditis. A definitive history of

rheumatic fever can only be obtained in 50% to 60% of cases and women are affected more often than

men by a 2:1 ratio.31,32 Rheumatic fever commonly occurs in childhood or adolescence and can lead to a

postinfective pancarditis, affecting to various degrees the valves, endocardium, myocardium, and

pericardium. In MS due to rheumatic fever, there is leaflet thickening and calcification, chordal

shortening and fusion, and commissural fusion, which all lead to a smaller, funnel-shaped mitral orifice.

This deformation can also prevent complete closure of the valve, which is evidenced by concomitant

regurgitation in about half of patients with MS.

Pathophysiology

The cross-sectional area of the normal MV is 4 to 5 cm2. Normally, there is a trivial diastolic pressure

gradient present to move blood across the MV from the left atrium into the left ventricle. An increasing

gradient is required as the MV becomes more narrowed, and a significant transvalvular gradient first

develops when there is reduction of the mitral orifice to less than 2.5 cm2, which represents mild MS.

The increased atrial pressure leads to left atrial enlargement and the pressure is subsequently

transmitted retrograde into the pulmonary veins, capillaries, and arteries. The determinants of the

transvalvular gradient, and therefore the determinants of the left atrial pressure, are atrial contractility,

cardiac output, and heart rate. Consequently, the gradient and atrial pressure are increased if atrial kick

is lost (decreased atrial contractility), flow rate across the valve increases (increased cardiac output), or

transit time across the valve is shortened (increased heart rate).

Diagnosis

Symptoms

Symptoms of left-sided heart failure, such as dyspnea, orthopnea, and paroxysmal nocturnal dyspnea,

are the primary indicators of MS and are typically triggered by exertion, stress, infection, pregnancy, or

the abrupt onset of atrial fibrillation. The increased heart rate and cardiac output that can occur under

these circumstances, and the mechanical obstruction inherent to MS, lead to an increased transvalvular

gradient and left atrial pressure. The ensuing pulmonary congestion results in dyspnea. Likewise, the

loss of atrial kick with atrial fibrillation increases the gradient and atrial pressure. Patients with atrial

fibrillation may also present with palpitations or systemic embolization.

Patients infrequently present with hoarseness, dysphagia, hemoptysis, and symptoms of right-sided

heart failure. Hoarseness and dysphagia may result if left atrial enlargement is sufficient to compress

surrounding structures. Hemoptysis may occur from significant pulmonary venous hypertension.

Symptoms of right-sided heart failure arise when right ventricular function is impaired due to an

increased afterload from the stenotic MV and secondary pulmonary hypertension. Still, other patients

may present without symptoms but have an abnormal physical examination.

Signs

The left ventricle is typically not enlarged; thus, the point of maximum impulse is not displaced. The

typical auscultatory findings of MS are best heard at the apex and include a low-pitched, rumbling

middiastolic murmur; an accentuated first heart sound; and an opening snap. These findings may be

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absent with a heavily calcified immobile valve, severe pulmonary hypertension, or low cardiac output.

Physical findings of pulmonary hypertension, such as a loud pulmonic component of the second heart

sound (P2

), a right ventricular heave, distended neck veins, hepatomegaly, ascites, and peripheral

edema, can also be observed with MS.16

Imaging

Echocardiography is the principal tool used in the diagnosis of MS. It is used to assess the morphologic

characteristics of the valve apparatus, which include leaflet mobility, flexibility, and thickness; presence

of calcifications and subvalvular fusion; and appearance of the commissures. Additionally, Doppler

echocardiography is utilized to determine the hemodynamic severity by measurement of the mean

transvalvular pressure gradient, pulmonary artery systolic pressure, and valve area (Table 82-3). This

morphology and severity information is fundamental in determining the timing and type of intervention

to be used.17

The enlarged left atrium gives rise to characteristic findings on the chest radiograph, which includes

displacement of the left main-stem bronchus superiorly and displacement of the esophagus posteriorly.

Additionally, calcification of the mitral leaflets and enlarged pulmonary arteries with cephalization of

pulmonary blood flow can be seen.

Similar to the diagnosis of other valvular heart disease, cardiac catheterization with direct pressure

measurement has largely been replaced by echocardiography.

DIAGNOSIS

Table 82-3 Classification of Mitral Stenosis Severity

Natural History

The natural history of MS is that of a continuous decline usually consisting of a slow, stable course

followed by a progressive acceleration. The latent period from rheumatic fever to the onset of

symptoms is typically 20 to 40 years, with another decade before symptoms become disabling.

Depending on the symptoms at presentation, the overall 10-year survival of untreated patients

presenting with MS is 50% to 60%. Once disabling symptoms occur, the 10-year survival is a bleak 0%

to 15%.31–34 Mortality in untreated patients is due to pulmonary and systemic congestion, systemic

embolism, pulmonary embolism, and infection.33,35

Treatment

For the asymptomatic patient with mild MS in sinus rhythm, prophylaxis against rheumatic fever is the

only therapy indicated. A yearly history, physical examination, chest radiograph, and electrocardiogram

should be obtained; serial echocardiograms are only warranted in patients with severe MS or when

there is a change in symptoms.17

Mechanical relief is considered in symptomatic patients with moderate to severe MS. In symptomatic

patients with mild MS, further exercise testing or dobutamine stress testing is useful to determine

whether or not mechanical relief is warranted. Patients with a significant elevation of mean transmitral

gradient (>15 mm Hg), pulmonary artery systolic pressure (>60 mm Hg), or pulmonary artery wedge

pressure (>25 mm Hg) during provocative testing have hemodynamically significant MS and should be

considered for mechanical relief.17 The options for mechanical relief of MS include percutaneous balloon

mitral valvotomy, open mitral commissurotomy (OMC), and MV replacement.

Percutaneous Balloon Mitral Valvotomy

Percutaneous balloon mitral valvuloplasty (PBMV) was initially introduced in 1984 marking a leap in

transcatheter-based therapies for valvular heart disease. Most commonly, the catheter is introduced into

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