Impact of mitral annular calcification on early and late outcomes following mitral valve repair of myxomatous degeneration.

OBJECTIVES: Mitral annular calcification is associated with significant morbidity and mortality at the time of mitral valve surgery. However, few data are available describing the impact of mitral annular calcification on early and late outcomes following mitral valve repair in the current era.
METHODS: Between 2001 and 2011, 625 patients were referred for mitral valve repair of severe mitral regurgitation due to myxomatous degeneration. The mean patient age was 63.9 ± 12.7 years and 164 (26%) were female. Concomitant coronary artery bypass grafting was performed in 91 (15%) and 24 (4%) had previous cardiac surgery. Calcification of the mitral annulus was observed in 119 patients (19%), of whom complete debridement and extensive annulus reconstruction were performed in 14. The mean follow-up was for 2.4 ± 2.3 years.
RESULTS: There were no deaths within 30 days of surgery. Risk factors associated with mitral annular calcification included older age (odds ratio 1.05 ± 0.02 per increasing year), female gender (odds ratio 1.88 ± 0.42) and larger preoperative left atrial size (odds ratio 1.04 ± 0.03 per increasing mm) (all P<0.01). Severe renal impairment defined as a creatinine clearance <30 mL/min was observed in 9 patients, all of whom had mitral annular calcification. Intraoperative conversion to mitral valve replacement was performed in 19 patients (97% repair rate), 5 of whom had mitral annular calcification. Extension of mitral annular calcification into one or more leaflet scallops was observed for all patients who required conversion to valve replacement. Five-year survival, freedom from recurrent mitral regurgitation ≥ 2+ and freedom from recurrent mitral regurgitation ≥ 3+ was 88.1 ± 2.4, 89.6 ± 2.3 and 97.8 ± 0.8%, respectively. Mitral annular calcification was not associated with survival or recurrent mitral regurgitation.
CONCLUSIONS: Risk factors for mitral annular calcification in patients with myxomatous degeneration and severe mitral regurgitation include older age, female gender, severe renal dysfunction and larger preoperative left atrial size. Nevertheless, favourable early and late results can be achieved with mitral valve repair in this population.