Effects of Surgical Techniques on Long-Term Results in Patients with Degenerative Mitral Valve Bileaflet Prolapse.

BACKGROUND AND AIM OF THE STUDY:The study aim was to evaluate the long-term results in patients with degenerative mitral valve bileaflet prolapse (DMVBLP) undergoing mitral valve repair (MVr) or mitral valve replacement (MVR), and to compare the consequences of survival related to each technique.METHODS:Between 2001 and 2012, a total of 421 patients underwent isolated primary surgery for DMVBLP. MVr was performed in 146 patients (34.7%), and MVR in 275 (65.3%). MVR patients were allocated to two subgroups. Subgroup A were operated on in routine fashion, preserving the posterior subvalvular apparatus, and in selected cases the anterior or both apparatus (n = 119; 43.3%). In subgroup B, surgery was performed without preservation of the subvalvular apparatus (n = 156; 56.7%).RESULTS:There were no intraoperative deaths in all patient groups. The median length of follow up was 5.96 ± 3.28 years. Five patients (3.4%) in the MVr group died, while 11 in MVR subgroup A (9.2%) died, and 29 in MVR subgroup B (18.6%). Patients in the MVr group demonstrated significant and persistent postoperative decreases in left ventricular end-diastolic diameter (LVEDD) and left ventricular end-systolic diameter (LVESD) during the follow up, while the left ventricular ejection fraction (LVEF) showed a trend to improve. In MVR subgroup A, preservation of the mitral subvalvular structures resulted in a decrease in LVEDD; this resulted in a lesser worsening of the LVEF, as occurs when subvalvular structures are resected. In MVR subgroup B, the LVEDD and LVESD were each increased constantly, which resulted in a statistically significant worsening of the LVEF.CONCLUSIONS:MVr in DMVBLP patients achieved a better preservation of left ventricular systolic indices than MVR, and guaranteed better shortand long-term survivals. When MVr is not feasible, it is recommended that subvalvular preservation be performed during MVR, in order to reduce the risk of early and late mortality and to improve left ventricular function.