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Has the Importance of Mitral Valve Prolapse Been Overestimated?

During the 1970s and 1980s, a spate of articles suggested that mitral valve prolapse (MVP) is very common and frequently associated with symptoms and complications. These two reports provide a different perspective.

Researchers in the Framingham Heart Study performed 2-D echocardiography in an unselected sample of 3,736 persons (mean age, 55 years; 53 percent women). According to current echocardiographic criteria, 47 (1.3 percent) had classic MVP (more than 2 mm prolapse, plus leaflet thickness of at least 5 mm), and 37 (1.1 percent) had nonclassic MVP (more than 2 mm prolapse without thickened leaflets). The prevalence of heart failure, atrial fibrillation, syncope, chest pain, and dyspnea was similar in those with and without MVP.

A case-control study from Massachusetts General Hospital investigated the alleged association between MVP and stroke in young people. Of 213 patients aged 45 or younger who were admitted with stroke or transient ischemic attack, 4 (1.9 percent) had MVP by 2-D echocardiography. The prevalence of MVP was similar (2.7 percent) among 263 controls with no stroke and no known heart disease. To explain the higher prevalences reported in previous studies, the researchers used older M-mode techniques on the same subjects. Depending on the angle of the beam, the prevalence of MVP could appear as high as 55 percent.

Comment: Taken together, these studies suggest that the prevalence of MVP and its propensity to cause symptoms and serious complications were overestimated in the past. The authors note that selection biases (e.g., use of hospital-based cohorts) and less accurate echocardiographic techniques are probably responsible for the findings in older research.

— AS Brett

Published in Journal Watch General Medicine July 13, 1999

Citation(s):

Freed LA et al. Prevalence and clinical outcome of mitral-valve prolapse. N Engl J Med 1999 Jul 1 341 1-7.

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• Medline abstract (Free)

Gilon D et al. Lack of evidence of an association between mitral-valve prolapse and stroke in young patients. N Engl J Med 1999 Jul 1 341 8-13.

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• Medline abstract (Free)