Lack of evidence of an association between mitral-valve prolapse and stroke in young patients

Background Previous studies have reported a high prevalence of mitral-valve prolapse among patients with embolic stroke (28 to 40 percent), especially among young patients (those less than or equal to 45 years old); this finding has practical implications for prophylaxis. However, diagnostic criteria for prolapse have changed and are now based on three-dimensional analysis of the shape of the valve; use of the current criteria reduces markedly the frequency of such a diagnosis and increases its specificity. Previously described complications must therefore be reconsidered. Methods In a case-control study, we reviewed data on 213 consecutive patients 45 years of age or younger with documented ischemic stroke or transient ischemic attack between 1985 and 1995; they underwent complete neurologic and echocardiographic evaluations. The prevalence of prolapse in these patients was compared with that in 263 control subjects without known heart disease, who were referred to our institution for assessment of ventricular function before receiving chemotherapy. Results Mitral-valve prolapse was present in 4 of the 213 young patients with stroke (1.9 percent), as compared with 7 of the 263 controls (2.7 percent); prolapse was present in 2 of 71 patients (2.8 percent) with otherwise unexplained stroke. The crude odds ratio for mitral-valve prolapse among the patients who had strokes, as compared with those who did not have strokes, was 0.70 (95 percent confidence interval, 0.15 to 2.80; P = 0.80); after adjustment for age and sex, the odds ratio was 0.59 (95 percent confidence interval, 0.12 to 2.50; P = 0.62). Conclusions Mitral-valve prolapse is considerably less common than previously reported among young patients with stroke or transient ischemic attack, including unexplained stroke, and no more common than among controls. Using more specific and currently accepted echocardiographic criteria, therefore, we could not demonstrate an association between the presence of mitral-valve prolapse and acute ischemic neurologic events in young people. (N Engl J Med 1999;341:8-13.) (C)1999, Massachusetts Medical Society.