Surgeons, cardiologists, and patients prefer mitral valve repair to mitral valve replacement for the correction of mitral regurgitation. Numerous studies confirm that mitral valve repair—compared with replacement—confers longer survival, better left ventricular function, and greater freedom from endocarditis, thromboembolism, and anticoagulant-related hemorrhage.1 Yet, despite these clearly demonstrated benefits, only a minority of patients undergoing isolated mitral valve surgery leave the operating room with a repaired valve; most are subjected to valve replacement and burdened with a lifetime of concerns and, in many cases, complications.2
In the future, we will see improved care of the patient who presents with mitral regurgitation. This will include simpler repair techniques, higher repair rates, and less invasive approaches. In addition, high-risk patients will have the option of percutaneous repair.
Simplified Repair Techniques and Higher Repair Rates
Carpentier and others established the principles of mitral valve repair, developing techniques for the management of leaflet prolapse and annular dilation.3 Today, surgical maneuvers are somewhat simpler, and this makes the mitral valve more accessible for repair.
Posterior leaflet prolapse is the most common finding in patients with isolated mitral regurgitation. Newer, simpler techniques have supplanted classic quadrangular resection and sliding repairs. Segmental posterior leaflet prolapse can be corrected by triangular resection—a simple, fast, and reproducible technique. Favoring leaflet conservation, many surgeons now use artificial chordae tendineae for posterior leaflet prolapse, particularly in the setting of diffuse prolapse.4 The application of these techniques enables secure repairs with short aortic cross-clamp times.
The creation of artificial chordae is now the preferred technique for management of anterior leaflet prolapse. Studies confirm the durability of this approach.5
The inclusion of an annuloplasty with all repairs improves durability. Whereas there has been some debate over the type of annuloplasty to use, most data show that prosthetic annuloplasty is the most important factor: the particular shape and composition matter little in patients who have degenerative disease.
Minimally Invasive Approaches
As repair outpaces replacement, minimally invasive techniques will become more common. Today, about one quarter of isolated mitral valve operations are minimally invasive, with the approach most often via the right side of the chest. Results from experienced centers confirm that right thoracic approaches enable excellent repairs in appropriately selected patients.6,7 The application of robotics facilitates even smaller incisions for mitral valve repair; however, robotic approaches are appropriate only for surgical teams that perform a large volume of mitral valve procedures, because a focused and deep learning curve is needed to gain expertise.
When considering a right thoracic approach to the mitral valve, the most important question is, “Who should not undergo this approach?” Improper patient selection jeopardizes results (Table I). Right thoracic approaches generally entail peripheral cannulation. Femoral cannulation, in particular, should be avoided in patients with small femoral vessels and in those with peripheral vascular disease or aortic atherosclerosis. A severe pectus excavatum deformity limits exposure via the right side of the chest, and the presence of aortic regurgitation creates challenges in myocardial protection.
Table I. Relative Contraindications to a Right Thoracic Approach to the Mitral Valve
Some surgeons favor right thoracic and robotic approaches in the sickest and frailest patients, believing that a less invasive approach will limit operative stress and improve outcomes. We disagree with this thinking. Robotic and right thoracic approaches generally entail somewhat longer periods of cardiopulmonary bypass and myocardial ischemia; these may be detrimental for a patient who is already severely compromised.
Percutaneous Mitral Valve Repair
The Everest II trial showed that application of the MitraClip Mitral Valve Repair System (Abbott Vascular; part of Abbott Laboratories; Santa Clara, Calif) can reduce mitral regurgitation in many patients.8 Although this approach leaves residual mitral regurgitation in most treated patients, it remains an attractive option for those who cannot tolerate surgery. We believe that its greatest application will come in patients who display reduced left ventricular function and have functional mitral regurgitation. Such patients might enjoy improved quality of life with a reduction in their mitral regurgitation.
Footnotes
Address for reprints: A. Marc Gillinov, MD, Desk J4-1, Department of Thoracic and Cardiovascular Surgery, Cleveland Clinic, 9500 Euclid Ave., Cleveland, OH 44195
★ CME Credit
Presented at the Joint Session of the Michael E. DeBakey International Surgical Society and the Denton A. Cooley Cardiovascular Surgical Society; Austin, Texas, 21–24 June 2012.
E-mail: gillinom@ccf.org
References
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