Non-myxomatous flail mitral valve: Clinical and echocardiographic characteristics and long-term clinical outcome

Background and aim of the study: Chordal rupture leading to flail mitral valve and mitral regurgitation (MR) is considered to be caused primarily by myxomatous mitral valve disease. The study aim was to determine the prevalence and clinical and echocardiographic characteristics of non-myxomatous versus myxomatous flail mitral valve. Methods: A total of 96 patients with flail mitral valve was identified from an echocardiography database and classified as either myxomatous (n = 36; 37%) or non-myxomatous (n = 60; 63%), based on echocardiographic mitral valve anatomy (systolic leaflet buckling). In 10 other patients the etiology was indeterminate. The clinical and echocardiographic characteristics and outcome at five years were compared between groups. Results: Patients with non-myxomatous mitral valve were older than those with myxomatous mitral valve (mean age 76 +/- 9 versus 61 +/- 12 years; p <0.0001), and were more likely to have aortic sclerosis, mitral annulus and papillary muscle calcification (odds ratio 3.6, 95% CI 1.2-10.8, p = 0.02) and to have short duration of symptoms (<= 1 month, p <0.02). There was no inter-group difference in MR severity, but non-myxomatous patients had higher systolic pulmonary artery pressure (52 +/- 16 versus 42 +/- 13 mmHg, p = 0.008). During the five-year follow up period, non-myxomatous patients had a poorer crude survival and survival free from rehospitalization for heart failure (p = 0.02), and were less likely to have mitral valve surgery (p = 0.015). However, these differences were abolished when data were adjusted for age. Conclusion: Among patients with flail mitral valve referred for echocardiography, more than half were non-myxomatous in origin, most likely due to wear and tear. Non-myxomatous flail mitral valve was associated with older age, degenerative calcific valvular changes, and more recent onset of symptoms. Age-adjusted survival free of heart failure was similar in both non-myxomatous and myxomatous patients.