Acquired Mitral Stenosis Workup

Updated: Apr 29, 2014
  • Author: M Silvana Horenstein, MD; Chief Editor: Stuart Berger, MD  more...
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Workup

Laboratory Studies

Rheumatic heart disease

Laboratory studies are nonspecific, unless the patient is experiencing an acute attack of recurrent rheumatic fever, in which case, C-reactive protein, sedimentation rate, and antistreptolysin O (ASLO) antibodies are evident

Chronic rheumatic mitral valve disease

Persistence of elevated levels of antibody to the streptococcal group A carbohydrate occur in most patients with chronic rheumatic mitral valve disease.

Systemic lupus erythematosus

Obtain studies for evaluation of antinuclear antibodies, antibodies to double stranded DNA, and lupus erythematosus (LE) cells.

Amyloidosis

Assess for amyloid deposits in affected tissues.

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Electrocardiography

ECG findings are often within reference ranges in patients with mild MS.

In those with moderate-to-severe MS, ECG reveals left atrial enlargement, right ventricular hypertrophy, and, often, right atrial enlargement. It also reveals atrial dysrhythmia. A fragmented QRS (RSR', R or S wave notching in 2 contiguous leads) has been described in patients who have severe MS, lower ejection fraction, and increased pulmonary artery pressure. [10]

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Histologic Findings

Cardiac involvement in rheumatic fever is characterized by inflammation of the endocardium and myocardium. Histologic changes are not observed during the early stage of myocarditis but become evident at later stages of the inflammatory process. The changes include tissue edema and a cellular infiltrate consisting of lymphocytes and plasma cells but few polymorphonuclear white blood cells.

Endocardial inflammation of the mitral valve produces essentially the same histologic changes observed in myocarditis.

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Chest Radiography

Findings on chest radiographs may include the following:

  • Left atrial enlargement

  • Pulmonic trunk and right ventricular and right atrial enlargement

  • Pulmonary venous congestion that results in redistribution of pulmonary blood flow with greater flow to the upper lobes and interstitial edema manifested by Kerley B lines

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Echocardiography

Transthoracic and transesophageal echocardiography are the most important diagnostic tools for evaluating patients with mitral stenosis (MS). Transesophageal echocardiography is recommended when transthoracic examination is incomplete, especially if left atrial thrombus is suspected. It is also used in the operating room and catheterization laboratory to assess the effectiveness of intervention.

Echocardiography provides the following:

  • Direct anatomic data is provided, including visualization of valve leaflet morphology and motility and measurement of valve orifice dimensions, as well as the degree of left atrial dilation.

  • Hemodynamic and physiologic data are provided, including the pressure gradient across the stenotic mitral valve, the presence and severity of mitral regurgitation, and the degree of pulmonary hypertension.

  • Spontaneous echo contrast is common in patients with MS, and its presence in the left atrium is associated with a higher risk of thromboembolism. One study postulated that platelet activation via increased sympathetic activity is responsible for this phenomenon. [11]

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Magnetic Resonance Imaging and Computed Tomography Scanning

MRI is infrequently used; however, experience with this imaging modality is much less than with echocardiography. [12]

Multislice CT scanning has been described as a new modality to assess the mitral valve area in patients with MS. [12, 13]

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Cardiac Catheterization

Cardiac catheterization can be used to obtain direct measurement of the pressure gradient across the mitral valve as well as pulmonary artery pressure and pulmonary vascular resistance.

Note the following:

  • The mitral valve area can be calculated using the Gorlin formula.

  • Currently, the diagnosis and hemodynamic assessment of patients with MS are performed noninvasively with echocardiography.

  • Cardiac catheterization may be needed to supplement the information obtained noninvasively. More commonly, it is performed to accomplish percutaneous balloon valvuloplasty.

  • Possible complications of cardiac catheterization include tachyarrhythmias, bradyarrhythmias, and vascular occlusion. Balloon valvuloplasty may result in significant mitral regurgitation.

  • Postcatheterization complications include hemorrhage, pain, nausea and vomiting, and arterial or venous obstruction from thrombosis or spasm.

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