Is a flexible mitral annuloplasty ring superior to a semi-rigid or rigid ring in terms of improvement in symptoms and survival?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether, in patients with mitral regurgitation secondary to degenerative mitral valve disease requiring mitral valve repair with an annuloplasty ring, a flexible ring is superior to a semi-rigid or rigid ring in terms of improvement in symptoms and survival. Using the reported search 478 papers were identified. Twelve papers of which seven were echocardiographic studies and five clinical studies, including two randomised controlled trials (RCTs), represented the best evidence on the subject. The author, journal, date and country of publication, patient group studied, study type, relevant outcomes, results and study comments and weaknesses were tabulated for these. We conclude that current best available evidence suggests that, in patients with a flexible annuloplasty ring compared to patients with a semi-rigid/rigid annuloplasty ring, the improvement in LV systolic function as reported by all the seven sophisticated echocardiographic studies with a total of 266 patients does not translate into better clinical outcomes as five clinical studies with a total of 941 patients, including two RCTs, report comparable clinical outcomes for patients with mitral regurgitation secondary to degenerative mitral valve disease requiring mitral valve repair with an annuloplasty ring.