Another chapter in an enlarging book: repair degenerative mitral valves.

See related article on page 1350. I n this issue of the Journal, Gillinov and colleagues provide us with another valuable contribution in the field of mitral valve repair from their large experience at The Cleveland Clinic Foundation available for sophisticated and cutting-edge (ie, Eugene Blackstone) statistical analysis. The superiority of mitral valve repair over replacement in patients with degenerative mitral valve disease is now widely held to be true. It would be surprising to see a single hand raised in a medical audience today if you asked, “Who would prefer to have his or her own valve replaced instead of repaired?” Intuitively it is attractive to keep the parts you were born with. Other potential advantages including better preservation of left ventricular function, avoidance of long-term anticoagulation (mechanical valves) or reoperation (bioprosthetic valves), and improved survival all favor mitral valve repair as the gold standard. Should the need for a concomitant coronary artery bypass procedure change the paradigm? This is the important question addressed by Gillinov and associates in their analysis of 679 patients with degenerative mitral valve disease and ischemic heart disease undergoing coronary bypass grafting and mitral valve surgery (repair or replacement). It is not surprising that their data provide further confirmation of the superiority of mitral valve repair over replacement in terms of survival, the only end point examined. Impressively, the benefit of mitral valve repair in patients with degenerative mitral regurgitation was noted as early as 2 years after the surgical procedure. This important observation reinforces that the necessity for coronary bypass grafting should not influence our determination to repair rather than replace a degenerative mitral valve. The authors were challenged by the retrospective nature of their analysis, which included patients undergoing surgery over a 3-decade span: (1) Valve replacements were more prevalent in the early phase of the study, whereas most of the valve repairs occurred after 1990. (2) Likewise, the use of the internal thoracic artery was much more common in later patients in their series, who were also more likely to receive a valve repair. (3) Both replacement and repair procedures underwent significant evolution during the study period. For example, chordal-sparing techniques in the valve replacement group became routine in the late 1980s, but this was not specifically determinable in individual patients. Similarly, valve repair techniques evolved over time, and repairs in their most recent experience were surely improved by the use of annuloplasty prosthetic rings as opposed to annuloplasty using bovine pericardium or non-annuloplasty techniques. (4) Myocardial preservation techniques also evolved and were surely more effective in the later era. (5) The understanding of the pathophysiology of mitral regurgitation and definition of degenerative mitral valve regurgitation also evolved over the study period. From the Department of Cardiothoracic Surgery, Mount Sinai Medical Center, New York, NY.