Outcomes of surgery in the treatment of isolated nonnative mitral valve infective endocarditis

Objective: We reviewed our experience with the operative management of patients with isolated nonnative mitral valve infective endocarditis to better understand the outcome. Methods: We reviewed the records of 39 patients operated on for isolated nonnative mitral valve infective endocarditis from January 1974 to June 2009. Median age of the group was 68 years. There were 23 (59%) women. Prostheses were mechanical in 18 (46%) patients, biological in 18 (46%), and annuloplasty rings in 3 (8%). Staphylococcus was present in 22 (56%) patients. Operative indications included valve dysfunction in 26 (67%) patients and heart failure in 22 (56%). Results: Perivalvular abscess was present in 12 (31%) patients. Replacement valves were mechanical in 23 (59%) patients and biological in 16 (41%). Twenty (51%) patients received additional operative procedures. Treatment-related mortality occurred in 8 (21%) patients, with age being the only factor predictive of mortality (hazard ratio, 5.37). Follow-up of the survivors was 5.7 years. Six (18%) patients underwent repeat mitral valve replacement including 3 who had an annulus abscess at the initial operation and 2 who had the prosthesis sutured to the left atrial wall. There was 1 (4%) case of recurrent endocarditis in the group of 28 patients who survived more than 1 year after the incident operation. Survival at 5 years was 48% (95% confidence interval, 35%-67%). Conclusions: Surgery for isolated nonnative mitral valve infective endocarditis carries increased operative risk. Aggressive debridement and reconstruction of the annulus are paramount to achieving a good outcome. Surviving patients obtain high rates of cure and freedom from recurrent infective endocarditis.