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In the case-control study,mitral valve strands were found in 22.5%of the case patients and in 12.1%of the control subjects.In the case subjects, mitral valve strands were more frequent in those with mitral valve dystrophy(52.4%versus 37.4%;P=.03).Strands were not associated with mitral valve prolapse,annular calcifications,or left atrial spontaneous echocardiographic contrast.After adjustment for age,sex,and mitral valve dystrophy,the odds ratio for ischemic stroke among patients with mitral strands was 2.2(95%confidence interval,1.4 to 3.6;P=.005).The frequency of strands was not different in patients with a known cause of brain infarction(24.4%)from that in patients with no other apparent cause(20. 9%).During 646 per 100 person-years of follow-up,the incidence of recurrent brain infarction was 6.0 person-years in patients with strands and 4.2 in those without.In the Cox analysis,including potential confounders and poststroke treatment,mitral valve strands did not appear as independent predictors of recurrent brain infarction(relative risk,1.3; 95%confidence interval,0.5 to 3.0;P=54).The present study shows an independent association between mitral valve strands and the risk of brain infarction.However,the lack of an increased relative risk of recurrence raises doubts about the potential causal relation with brain infarction in patients aged 60 years or older. |
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