TITLE: Mid- to Long-term Survival for Asymptomatic Patients Who Undergo Mitral Repair For Severe Degenerative Mitral Valve Regurgitation – Should We Wait For Symptoms?
OBJECTIVES: There is increasing support for the concept of surgical intervention in patients with severe degenerative mitral valve repair who are asymptomatic. We aimed to evaluate our experience of undertaking mitral repair in this patient group with a view to providing further evidence to help clarify this controversial area.
METHODS: We performed a retrospective analysis of a prospectively collected database of patients who had undergone first time mitral repair for severe degenerative mitral valve regurgitation at a single institution, between 2001 and 2012 (11 years). Patients were included with or without concomitant CABG, tricuspid repair or AF ablation. Patients were excluded if they had undergone concomitant AVR. The cohort of patients was divided into 2 groups based on NYHA status; Group 1 were NYHA 1 (Asymptomatic) and Group 2 were a combination of NYHA 2-4 (symptomatic). Time to event survival analysis was performed with all-cause mortality as the outcome measure. Multivariate Cox regression analyses was used to measure the associations between the Groups and all-cause mortality after adjusting for pre-operative variables. Unadjusted Kaplan-Meyer curves were used to show survival analysis. Risk estimates were presented as hazard ratios with 95% confidence intervals. Log rank tests were performed to compare survival curves. Results for all analyses were considered statistically significant at p values < 0.05. Data analyses were performed using STATA 12®.
RESULTS: A total of 615 patients (64% male) were included; 94(15.3%) in Group 1 (NHYA1) and 521 (84.7%) in Group 2 (NHYA 2-4). Concomitant CABG was undertaken in 20 patients (3.25%), tricuspid repair in 173 (28%) and AF ablation in 31 (5%). Median follow up was 4.9 years (IQR 2.5-8.2 years). In-hospital mortality was 2.8% in the total cohort and 0% for Group 1 and 3.3% for Group 2. Mutivariate Cox regression analysis showed that after adjustment for pre-operative confounding variables, Group 2 patients (NHYA 2-4) had increase mid- to long-term mortality compared to the asymptomatic Group 1 (NHYA 1) (HR 2.8, 95% CI 1.2-6.2, P<0.05). Unadjusted Kaplan-Meyer curves are displayed which shows this out to beyond 10 years.
CONCLUSIONS: Our data provides further support for the concept that asymptomatic patients with severe degenerative mitral regurgitation should undergo early surgery before symptoms develop. This should only be offered by a Surgeon with a high repair rate and has a proven low operative mortality for mitral repair procedures.