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Key Concepts

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  • Prosthetic valve design

    • Design of both mechanical and bioprosthetic valves has continued to evolve since the invention of the first valve to improve flow dynamics, reliability, and durability, while minimizing thrombogenicity and avoiding structural valve dysfunction (SVD).

  • Indications

    • Mitral valve (MV) surgery is recommended for symptomatic acute severe mitral regurgitation (MR), chronic severe MR with New York Heart Association (NYHA) class II, III, or IV symptoms and no severe left ventricular (LV) dysfunction, and asymptomatic patients with mild-to-moderate LV dysfunction and severe MR. MV surgery is reasonable for asymptomatic severe MR in some cases. Mitral replacement in the setting of MR should be performed when repair is not possible or the functional result would be inadequate.

    • The indications for MV replacement in mitral stenosis are the following: (1) moderate (mean valve area ≤1.5 cm2) or severe MS (mean valve area ≤1.0 cm2) and NYHA functional class III or IV symptoms if they are not candidates for percutaneous balloon valvotomy or MV repair; and (2) severe MS with moderate-to-severe MR in symptomatic patients. MV replacement may be indicated for patients with severe MS with pulmonary hypertension and NYHA class I or II symptoms.

  • Treatment (surgical)

    • The choice of prosthetic valve type is rooted in an understanding of valve features that determine thrombogenicity (the need for anticoagulation) and durability, as these factors relate to patient characteristics.

    • The most appropriate surgical approach to the MV is determined by patient characteristics and surgeon expertise. Typically, a median sternotomy, right thoracotomy, or mini right thoracotomy is employed. Aortic or femoral arterial cannulation and bicaval or femoral venous cannulation is performed depending on the incision. Venting may be performed through the aortic root and left atrium or left ventricle across the valve, and cardioplegia is given antegrade and retrograde. The valve may be exposed through a transverse incision in the left atrium or through a transseptal approach.

    • The chordal sparing technique of MV replacement improves LV function and survival. Valve stitches may be everting or noneverting.

    • Warfarin therapy with a goal INR of 2.5 to 3.5 is indicated after MV replacement with a mechanical prosthesis. Early anticoagulation for patients with bioprosthetic MVs is controversial.

  • Outcomes/prognosis

    • MV replacement can be performed with outstanding efficacy, and risk is proportional to patient and surgical risk factors that can be assessed using well-established risk scoring systems. Acute surgical complications typically arise from problems with cardiopulmonary bypass or a combination of technical mistakes and patient factors. Late complications are rare and usually include prosthetic valvular endocarditis, thrombosis/anticoagulation, or SVD.

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Introduction

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History of Mitral Valve Replacement

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The advent of cardiopulmonary bypass in 1953 opened the door for open cardiac surgery, but the first mitral valve (MV) replacement was not performed until 1959 at the National Heart Institute by Nina Starr Braunwald (Fig. 35-1A), the first woman to perform cardiac surgery.1 Modeling anatomy, she designed the ...

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