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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 e118

CLINICAL STATEMENTS AND GUIDELINES intervention.14,39 An elevated pulmonary arterial resistance before intervention is associated with RV dysfunction and TR after the procedure.40–42 Thus, PMBC may prevent the adverse consequences of irreversible pulmonary hypertension if it can be performed with a high success rate and low risk in patients who are developing pulmonary hypertension. Correction of the MR before irreversible changes occur can be curative. Thus, in chronic primary MR, MR is the disease. 4.	 The new onset of AF may be an indication for proceeding with PMBC in the asymptomatic patient with a favorable valve morphology for several reasons. First, AF may be the equivalent of symptom onset, signifying that rheumatic MS is resulting in progressive LA damage. Second, AF increases the risk of thromboembolic events in patients with rheumatic MS. In addition, a shortened diastolic filling interval with AF and a rapid ventricular response further increase LV pressure. Finally, the presence of AF is associated with worse outcomes in patients with rheumatic MS and with suboptimal results after PMBC.43 In theory, lowering a high LA pressure after PMBC might be beneficial in restoring normal sinus rhythm. Although there is no randomized trial to prove the effectiveness of intervening early, there is a documented improvement in P-wave dispersion after PMBC, which may affect the ability to restore normal sinus rhythm.15

5.	 Some patients have symptoms from rheumatic MS even with a mitral valve area >1.5 cm2 and a resting mean transmitral gradient <10 mm Hg. This may be related to the variability and reliability of measuring a mitral valve area by either planimetering a short-axis image of the mitral valve or using a diastolic half-time for indirect calculation of the mitral valve area. There are also patients who have a relatively low gradient at rest who generate a much higher gradient with exercise, with symptoms developing from the higher LA pressure. Thus, in these patients in whom there is a discrepancy between the clinical symptoms and the resting hemodynamics, exercise testing with measurement of the mean transmitral gradient or the direct pulmonary artery wedge, or both, is useful.44–48 Patients who increase their gradients to >15 mm Hg with exercise have been shown to improve symptomatically after PMBC.16 6.	 Both anatomic valve morphology and the presence of commissural calcification predict successful PMBC. However, in all such series, this predictive ability is not absolute, with 42% of patients with an anatomic valve Wilkins morphology score >822,23,31,32 having an optimal outcome (25% increase in mitral valve area to >1.5 cm2) and 38% of patients with commissural calcium having event-free survival at 1.8 years.18,19,22,23 Accordingly, severely symptomatic patients who are poor surgical candidates may benefit from PMBC even with suboptimal valve anatomy.17 Patients who refuse surgery may also be offered PMBC after discussion about the potential complications associated with this procedure when it is performed in patients with suboptimal valve anatomy.

6.3 Nonrheumatic Calcific MS

Recommendation for Nonrheumatic Calcific MS COR LOE Recommendation

2b C-LD 1.  In severely symptomatic patients (NYHA class III or IV) with severe MS (mitral valve area ≤1.5 cm2, Stage D) attributable to extensive mitral annular calcification, valve intervention may be considered only after discussion of the high procedural risk and the individual patient’s preferences and values.1–3

Synopsis

Although most MS in the world results from rheumatic heart disease, calcific MS is found with increasing frequency in the elderly population in high-income countries.2–10 Calcific MS is the result of calcification of the mitral annulus that extends into the leaflet bases, resulting both in narrowing of the annulus and rigidity of the leaflets. In contrast to rheumatic MS, there is no commissural fusion, and the leaflet tips are usually unaffected. The progression of calcific MS is variable, ranging from an increase of <1.0 to up to 9 mm Hg per year.9,11 The prognosis of this group of patients is poor, with a 5-year survival rate <50%, most likely because of advanced age and other comorbidities.4 Determination of the severity of stenosis is difficult because of extensive calcification, which prevents measurement of an accurate planimetered area, and the significant abnormalities of LA and LV compliance, which cause a high gradient in the absence of severe obstruction.12–16 These patients are at high risk with any intervention because of the extensive calcification, as well as advanced age and multiple comorbidities. Thus, in patients with calcific MS, the indications for any intervention differ from those for rheumatic MS, and intervention for calcific MS should be performed only in the highly symptomatic patient. Nonrheumatic MS can also be present after radiation therapy and after a mitral valve repair with a small annuloplasty ring.

Recommendation-Specific Supportive Text

1.	 Indications for intervention in patients with calcific MS are different from those for rheumatic MS for the following reasons. First, because calcification involves the annulus and base of the leaflets without commissural fusion, there is no role

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