This chapter discusses the surgical indications, operative techniques, and early and late follow-up after implantation of mechanical and bioprosthetic mitral valve devices. The valves that are discussed are those that are currently (2010) approved by the FDA. Figure 42-1 shows the current FDA-approved prosthetic mitral valve devices, including the Starr-Edwards ball-and-cage valve (historical relevance only), the Omnicarbon tilting-disk valve, the Medtronic Hall tilting-disk valve, the St. Jude Medical bileaflet valve, the Carbomedics bileaflet valve, the ATS bileaflet valve, and the On-X bileaflet valve. The FDA-approved bioprosthetic valve devices are shown in Fig. 42-2 and include the Hancock II porcine valve, the Carpentier-Edwards porcine valve, the Carpentier-Edwards pericardial valve, the Mosaic porcine valve, and the Biocor porcine valve.
FDA-approved mechanical mitral valves. (A) Starr-Edwards ball-and-cage. (B) Medtronic Hall tilting-disk. (C) Omnicarbon tilting-disk. (D) St. Jude Medical bifleaflet. (E) Carbomedics bileaflet. (F) ATS bileaflet. (G) On-X bileaflet.
FDA-approved bioprosthetic mitral valves. (A) Hancock II porcine heterograft. (B) Carpentier-Edwards standard porcine heterograft. (C) Mosaic porcine heterograft. (D) Carpentier-Edwards pericardial bovine heterograft. (E) St. Jude Biocor porcine heterograft.
Heart valve prostheses are continually undergoing iterative advancement by the manufacturers, and the future device of choice has yet to be developed. This ideal replacement valve prosthetic would have longevity of a mechanical prosthetic combined with the superior hemodynamic function of the native biologic tissue valve. As a result this hypostatic ideal replacement device would not require anticoagulation and carrying no risk of either thromboembolic events or valve thrombosis. To achieve this goal will require major advancement away from current design.
The indications for mitral valve replacement are variable and undergoing evolution. Because of increasing use of reparative techniques, particularly for mitral regurgitation, replacement or repair of a mitral valve often depends on the experience of the operating surgeon. Current indications for valve replacement pertain to those types of valve problems that are unlikely to be repaired by most surgeons or which have been shown to have poor long-term success after reconstruction. Indications are discussed according to: (1) pathophysiologic states; and (2) type of valve required (ie, mechanical or bioprosthetic).
Mitral stenosis is almost exclusively caused by rheumatic fever, even though a definite clinical history can be obtained in only about 50% of patients. The incidence of mitral stenosis has decreased substantially in the United States in the last several decades because of effective prophylaxis of rheumatic fever, nevertheless in certain developing countries mitral stenosis is still very common. Two-thirds of patients with rheumatic mitral stenosis are female.