Laboratory Studies
Brain natriuretic peptide may be useful in determining the presence of heart failure in an undifferentiated patient with dyspnea. [25]
Troponin I and creatinine kinase levels may be useful in excluding acute myocardial infarction in patients who present with symptomatic mitral stenosis (MS).
Imaging Studies
Two-dimensional (2D) or three-dimensional (3D) transesophageal echocardiography and Doppler echocardiography is the preferred initial diagnostic modality. [2] It initially confirms diagnosis and also assesses valve function whenever symptoms or physical examination findings change. [26, 27] See the video below.
Two-dimensional echocardiography evaluates the morphology of the mitral valve. Orifice size can be measured. Leaflet mobility, thickness, calcification, and fusion may be noted. Additionally, 2D echocardiography allows evaluation of the structure and potential disease in the cardiac chambers and other valves.
Doppler echocardiography is the most accurate noninvasive technique to quantify the hemodynamic severity of mitral stenosis at rest or with exercise. It measures the transvalvular pressure gradient and the pulmonary arterial pressure and determines whether mitral regurgitation, aortic regurgitation, and other valvular abnormalities coexist.
If 2D or 3D echocardiography is inadequate or inconclusive, transesophageal echocardiography (TEE) may be indicated. TEE provides better images of the mitral valve anatomy and is a more sensitive way to detect pathology such as valvular vegetations or atrial thrombus; anomalies that should be identified before valvotomy is pursued.
Three-dimensional (3D) echocardiography has become increasingly available over the last decade, and studies show that 3D echocardiography is superior to 2D echocardiography in the evaluation of mitral valve stenosis because it can provide useful information on mitral valve area measurements. [28, 29]
Use chest radiography to look for left atrial, pulmonary artery, right ventricle, and/or right atrium enlargement (eg, straightening of left heart border, loss of aortic window). Rarely, calcification of the mitral valve may be seen. Radiologic changes in the lung fields indirectly reflect the severity of mitral stenosis. Interstitial edema manifests as Kerley B lines. Severe, long-standing mitral obstruction results in Kerley A lines.
Other Tests
Electrocardiography (ECG) is relatively insensitive for mild mitral stenosis.
Ninety percent of patients with significant mitral stenosis and sinus rhythm display electrical evidence of left atrial enlargement. P-mitrale in lead II and/or a biphasic P wave in lead V1 with a wide negative deflection greater than 0.04 seconds is observed.
The QRS axis in the frontal plane correlates with the severity of valve obstruction in pure mitral stenosis. A mean axis 0-60º suggests a mitral valve area of more than 1.3 cm2, whereas an axis of more than 60º suggests a valve area less than 1.3 cm2.
Atrial fibrillation usually develops in the presence of preexisting left atrial enlargement. With severe pulmonary hypertension, right-axis deviation and right ventricular hypertrophy can be seen. The ECG of right ventricular hypertrophy typically shows tall R waves in the right chest leads, and the R wave may be taller than the S wave in lead V1. In addition, right-axis deviation and right precordial T-wave inversions are often present.
Procedures
Exercise stress testing
Exercise stress testing is indicated in situations where the degree of disability is in question.
Stress echocardiography provides information about changes in the transmitral gradient and the degree of limitation of exercise and may guide decisions about valvotomy.
Cardiac catheterization
Cardiac catheterization is indicated when a discrepancy is noted between Doppler-derived hemodynamics and the clinical status in a symptomatic patient.
Perform percutaneous mitral balloon valvotomy in properly selected patients.
Cardiac catheterization measures absolute left-sided and right-sided pressure when pulmonary artery pressure elevation is out of proportion to mean gradient and valve area.
Coronary angiography may be performed in selected patients.
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Mitral stenosis.
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Echocardiography of mitral stenosis. Courtesy of Michael B. Stone, MD, RDMS.
Tables
Recommendation |
AHA/ACC (2014) [2] |
|
Concomitant mitral valve surgery for patients with severe MS (stage C or D) undergoing other cardiac surgery |
Class I |
|
Percutaneous mitral balloon commissurotomy (PMBC) for asymptomatic patients with very severe MS (stage C) and favorable valve morphology in the absence of left atrial (LA) thrombus or moderate-to-severe mitral regurgitation (MR) |
Class IIa: Reasonable |
|
PMBC for asymptomatic patients without unfavorable clinical characteristics when the risk of thromboembolism or hemodynamic decompensation is high |
Class IIa: Reasonable |
|
Mitral valve surgery for severely symptomatic patients (NYHA class III/IV) with severe MS (stage D), provided there are other operative indications |
Class IIa: Reasonable |
|
PMBC for asymptomatic patients with severe MS (stage C) and favorable valve morphology who have new onset of atrial fibrillation (AF) in the absence of an LA thrombus or moderate-to-severe MR |
Class IIb: Consider |
|
PMBC for symptomatic patients with a mitral valve area (MVA) above1.5 cm² if there is evidence of hemodynamically significant MS during exercise |
Class IIb: Consider |
|
PMBC for severely symptomatic patients (NYHA class III/IV) with severe MS (stage D) who have suboptimal valve anatomy and are not candidates or are at high risk for surgery |
Class IIb: Consider |
Class IIa: Reasonable |
Concomitant mitral valve surgery for patients with moderate MS undergoing cardiac surgery for other causes |
Class IIb: Consider |
|
Mitral valve surgery and excision of the LA appendage for patients with severe MS (stages C and D) who have had recurrent embolic events while receiving anticoagulation |
Class IIb: Consider |
