p.43 抽出テキスト

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

February 2, 2021 Circulation. 2021;143:e72–e227. DOI: 10.1161/CIR.0000000000000923 e114

CLINICAL STATEMENTS AND GUIDELINES and suitability for PMBC. If PMBC is being considered, a TEE can further evaluate the presence and severity of concomitant MR and rule out LA thrombus.

Recommendation-Specific Supportive Text

1.	 TTE is the imaging modality of choice to elucidate the anatomy and functional significance of rheumatic MS.1 The parasternal long-axis window can identify the characteristic diastolic doming of the mitral valve, whereas short-axis scanning will demonstrate commissural fusion and allow planimetry of the mitral orifice. Use of 3D echocardiography (either TTE or TEE) provides greater accuracy of measurement of the mitral valve area.7,8 Doppler echocardiography mean transvalvular gradients always should be reported with heart rate because a high heart rate will result in overestimation of stenosis severity.9 Estimated RV systolic pressure is obtained from the TR velocity. Concomitant MR should be quantified, along with any other valve lesions (Section 7.3.1.1). Several scores are available for evaluation of mitral valve morphology and prediction of outcomes with PMBC, and these scores consider valve thickening, mobility, and calcification with subvalvular chordal fusion.10,11 Characterization of commissural morphology and calcification further predicts suitability for commissurotomy.2,3,12,13 Additional assessment of rheumatic MS includes the mitral pressure half-time, with acknowledgment that this parameter is also affected by LA and LV compliance. If the mean gradient does not match the valve area, other methods, such as the continuity equation, should be considered.14 2.	 TEE offers excellent visualization of the mitral valve and LA and is an alternative approach to assessment of rheumatic MS in patients whose TTE images are technically limited. In patients being considered for PMBC, a TEE can rule out LA cavity and appendage thrombi.4–6 TEE also is useful for evaluation of MR severity in patients being considered for PMBC because shadowing of the LA on TTE may result in underestimation of MR severity. MR that is more than mild is a contraindication to PMBC. 6.2.1.2. Diagnostic Testing: Changing Signs or Symptoms Patients with an established diagnosis of rheumatic MS may experience a change in symptoms attributable to disease progression related to recurrent episodes of rheumatic fever leading to further valve damage; progressive narrowing of the mitral valve attributable to leaflet fibrosis and thickening; progressive pulmonary hypertension; or worsening of concomitant MR or other valve lesions. In addition, symptom status may change with no change in rheumatic MS severity because of an increased hemodynamic load (for example, because of pregnancy), new-onset or rapid AF, fever, anemia, or hyperthyroidism, or hemodynamic shifts in the perioperative period of patients undergoing noncardiac surgery. In such cases, a repeat TTE examination can quantify the mitral valve gradient and area, as well as other parameters that may contribute to a change in symptoms.

6.2.1.3. Diagnostic Testing: Routine Follow-Up Rheumatic MS is a slowly progressive disease, characterized by a prolonged latent phase between the initial rheumatic illness and the development of valve stenosis.1–3 The latent phase is an interval typically measured in decades in high-income countries but in considerably shorter periods in low- to middle-income countries, likely because of recurrent carditis. Once mild stenosis has developed, further narrowing is slow (decrease in valve area of 0.1 cm2 per year on average), although the rate of progression is highly variable.3 Importantly, progressive enlargement of the RV and a rise in RV systolic pressure can be observed, even in the absence of a decrease in mitral valve area. Accordingly, repeat TTE at intervals dictated by valve area is an important aspect of disease management, even in patients without symptoms (Table 4). 6.2.1.4. Diagnostic Testing: Cardiac Catheterization In the contemporary era, assessment of MS and associated lesions can be obtained in most patients by TTE, occasionally supplemented by TEE. However, there will be a subset of patients with nondiagnostic studies or for whom there is discordance between the clinical and echocardiographic findings. In older patients, other factors contributing to symptoms may need to be further sorted out, such as concomitant diastolic dysfunction, LA noncompliance, or intrinsic pulmonary vascular disease. Cardiac catheterization is useful in these patients to further characterize rheumatic MS hemodynamics and etiology of symptoms, as it can measure absolute pressures in the LV, LA, and pulmonary circulation at rest and with exercise. Although the mean pulmonary artery wedge pressure is an acceptable substitute for mean LA pressure, the LV–to–pulmonary wedge gradient will overestimate the true transmitral gradient because of phase delay and delayed transmission of pressure changes.1 Nonetheless, the absolute mean pulmonary artery wedge pressure and its relationship to the LV diastolic pressure and pulmonary artery pressure can provide useful clinical information. The Gorlin equation can be used for an independent calculation of mitral valve area.2,3

Downloaded from http://ahajournals.org by on October 7, 2026