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Otto et al 2020 ACC/AHA Guideline for the Management of Valvular Heart Disease

Circulation. 2021;143:e72–e227. DOI: 10.1161/CIR.0000000000000923 February 2, 2021 e113 CLINICAL STATEMENTS AND GUIDELINES

with commissural fusion but pliable noncalcified valve leaflets. In contrast, the presentation in regions with a low disease prevalence occurs more often in older patients (age 50 to 70 years) who present decades after the initial rheumatic fever episode with calcified fibrotic leaflets in addition to commissural fusion and subvalvular involvement. Older patients with MS often have multiple other cardiac and noncardiac comorbidities, such as atherosclerotic disease, hypertension, and diastolic dysfunction, all of which need to be taken into consideration in patient evaluation and management.1,2 Although most of MS in the world results from rheumatic heart disease, nonrheumatic calcific MS is found with increasing frequency in the elderly population in high-income countries Calcific MS is the result of calcification of the mitral annulus that extends into the leaflet bases, resulting in both narrowing of the annulus and rigidity of the leaflets.3–5

6.1 Stages of MS

The stages of MS are defined by patient symptoms, valve anatomy, valve hemodynamics, and the consequences of valve obstruction on the left atrium (LA) and pulmonary circulation (Table  16). Rheumatic valve disease is the primary cause of MS, with anatomic features reflecting this disease process. Hemodynamic severity is best characterized by valve area, either directly planimetered by 2D or 3D imaging or calculated from the diastolic pressure half-time.1 The definition of “severe” MS is based on the severity of symptoms, as well as the severity at which intervention will improve symptoms. Thus, a mitral valve area ≤1.5 cm2 is considered severe, which typically corresponds to a transmitral mean gradient of >5 mm Hg to 10 mm Hg at a normal heart rate. However, mean pressure gradient is highly dependent on transvalvular flow rate, the diastolic filling period, and heart rate. Mitral pressure half-time also has limitations, and is dependent upon LV and LA compliance as well as stenosis severity. Other approaches to calculation of the mitral valve area, such as the continuity equation or Gorlin formula, may be used if discrepancies exist. These pertain primarily to patients with rheumatic MS.

6.2 Rheumatic MS

6.2.1 Diagnosis and Follow-Up of Rheumatic MS

6.2.1.1 Diagnostic Testing: Initial Diagnosis

Recommendations for Diagnostic Testing: Initial Diagnosis of Rheumatic MS Referenced studies that support the recommendations are summarized in Online Data Supplement 19. COR LOE Recommendations

1 B-NR 1.  In patients with signs or symptoms of rheumatic MS, TTE is indicated to establish the diagnosis, quantify hemodynamic severity, assess concomitant valvular lesions, and demonstrate valve morphology (to determine suitability for mitral commissurotomy).1–3

1 C-LD 2.  In patients considered for percutaneous mitral balloon commissurotomy (PMBC), TEE should be performed to assess the presence or absence of LA thrombus and to evaluate the severity of MR.4–6

Synopsis

For patients with rheumatic MS, TTE is the initial diagnostic test to determine the severity of the stenosis

Table 16.  Stages of MS

Stage Definition Valve Anatomy Valve Hemodynamics Hemodynamic Consequences Symptoms A At risk of MS Mild valve doming during diastole Normal transmitral flow velocity None None B Progressive MS Rheumatic valve changes with commissural fusion and diastolic doming of the mitral valve leaflets

Planimetered mitral valve area >1.5 cm2 Increased transmitral flow velocities

Mitral valve area >1.5 cm2 Diastolic pressure half-time <150 ms Mild to moderate LA enlargement

Normal pulmonary pressure at rest None

C Asymptomatic severe MS Rheumatic valve changes with commissural fusion and diastolic doming of the mitral valve leaflets

Planimetered mitral valve area ≤1.5 cm2 Mitral valve area ≤1.5 cm2

Diastolic pressure half-time ≥150 ms Severe LA enlargement

Elevated PASP >50 mm Hg None

D Symptomatic severe MS Rheumatic valve changes with commissural fusion and diastolic doming of the mitral valve leaflets

Planimetered mitral valve area ≤1.5 cm2 Mitral valve area ≤1.5 cm2

Diastolic pressure half-time ≥150 ms Severe LA enlargement

Elevated PASP >50 mm Hg Decreased exercise tolerance

Exertional dyspnea

The transmitral mean pressure gradient should be obtained to further determine the hemodynamic effect of the MS and is usually >5 mm Hg to 10 mm Hg in severe MS; however, because of the variability of the mean pressure gradient with heart rate and forward flow, it has not been included in the criteria for severity.

LA indicates left atrial; MS, mitral stenosis; and PASP, pulmonary artery systolic pressure.

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