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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 e126

CLINICAL STATEMENTS AND GUIDELINES approach. Thus, there must be a high degree of certainty that a durable repair can be performed. This certainty comes from the track record of the surgical team in operating on the specific type of lesion under consideration. Thus, asymptomatic patients should be treated in a Comprehensive Valve Center.21,24,27–29 In excellent hands, patients with severe MR from flail leaflets who undergo early operation as opposed to watchful waiting have a lower risk of developing HF and lower mortality rates.4,13,15

5.	 MR may lead to progressively more severe MR as the initial level of MR causes LV dilation, which increases stress on the mitral apparatus, causing further damage to the valve apparatus, more severe MR, and further LV dilation—thus initiating a perpetual cycle of ever-increasing LV volumes and MR. Longstanding volume overload leads to irreversible LV dysfunction and a poorer prognosis. Patients with severe MR who develop an LVEF <60% or LVESD ≥40 mm have already developed LV systolic dysfunction.5,6 One study has suggested that for LV function and size to return to normal after mitral valve repair, the LVEF should be >64% and LVESD <37 mm.16 Thus, when longitudinal follow-up demonstrates a progressive decrease of LVEF toward 60% or a progressive increase in LVESD approaching 40 mm, it is reasonable to consider intervention.41 In severe MR, TTE is recommended at 3- to 6-month intervals or more frequently as the ventricle enlarges. 6.	 Mitral transcatheter edge-to-edge repair (TEER) with the anterior and posterior leaflets clipped together at ≥1 locations is safe and effective in treating severely symptomatic patients with primary MR who are at high or prohibitive surgical risk.17,18,42 Studies of TEER with a mitral valve clip have demonstrated improved symptoms and a reduction in MR by 2 to 3 grades, leading to reverse remodeling of the LV. Superior outcomes were shown with surgery versus TEER, and thus it is only the patients who are at high or prohibitive risk for surgery for whom TEER is performed. 7.	 Rheumatic mitral valve disease is less suitable for mitral repair compared with complex degenerative disease. Durability of the repair is limited by thickened or calcified leaflets, extensive subvalvular disease with chordal fusion and shortening, and progression of rheumatic disease. Freedom from reoperation at 20 years, even in experienced hands, is in the 50% to 60% range. In a large series from Korea, repair was accomplished in 22% of patients operated on for rheumatic disease.19 One-third of these patients who underwent repair had significant stenosis or regurgitation at 10 years. Repair of rheumatic mitral valve disease should be limited to patients with less advanced disease in whom a durable repair can be accomplished or to patients in whom a mechanical prosthesis cannot be used because of anticoagulation management concerns.43

8.	 Mitral valve repair is the procedure of choice for isolated severe primary MR limited to less than one-half of the posterior leaflet, and mitral valve replacement is inappropriate unless mitral valve repair has been attempted and was unsuccessful.11–14,21,22 Surgical repair of primary MR has been remarkably successful. Repair of isolated degenerative mitral disease, when leaflet dysfunction is sufficiently limited that only annuloplasty and repair of the posterior leaflet are necessary, has led to outcomes distinctly superior to those with biological or mechanical mitral valve replacement.11–14 Repair is associated with an operative mortality rate of <1%, long-term survival rate equivalent to that of age-matched general population, approximately 95% freedom from reoperation, and >80% freedom from recurrent moderate or severe (≥3) MR at 15 to 20 years after surgery.15,39 As much as one-half of the posterior leaflet may be excised, plicated, or resuspended. Posterior leaflet repair has become sufficiently standardized in this situation so that repair, rather than mitral valve replacement, is the standard of care. Execution of this procedure with a success rate ≥95% should be the expectation of every cardiac surgeon who performs mitral valve procedures.

7.3 Chronic Secondary MR

7.3.1 Stages of Chronic Secondary MR

In chronic secondary MR, the mitral valve leaflets and chords usually are normal or minimally thickened. Instead, MR is associated with severe LV dysfunction caused by CAD (ischemic chronic secondary MR) or idiopathic myocardial disease (nonischemic chronic secondary MR). The abnormal and dilated LV causes papillary muscle displacement, which in turn results in leaflet tethering with associated annular dilation that prevents adequate leaflet coaptation. Secondary MR may also develop because of LA dilation and enlargement of the mitral annulus, which often occurs with AF and other cardiomyopathies. There are instances in which both primary and secondary MR are present. The best therapy for chronic secondary MR is not clear because MR is only one component of the disease, and restoration of mitral valve competence is not curative. The optimal criteria for defining severe secondary MR have been controversial. Compared with primary MR, adverse outcomes in secondary MR are associated with a smaller

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