Objectives: Significant mitral regurgitation (MR) may arise from isolated annular dilatation secondary to lone atrial fibrillation (AF) and associated atrial remodelling. The aim of the present study is to assess the outcome of surgery for this condition.
Methods: Between November 2007 and July 2011, 20 patients underwent mitral valve (MV) repair for severe MR secondary to AF. The median age of patients was 77.5 years (45-82 years) and the mean pre-operative duration of AF was 84.6 ± 92 months. The left ventricle was moderately (ejection fraction 30-50%; n = 6) or severely (<30%; n = 1) impaired in seven patients pre-operatively. Mean logistic EuroSCORE was 8.1 ± 5.9 and mean follow-up was 18.0 ± 12.5 months.
Results: All operations were elective. Concomitant anti-arrhythmic procedures (maze procedure, pulmonary vein isolation) or left atrial (LA) appendage amputation were performed in all patients; tricuspid valve repair was undertaken in 12 patients and coronary artery bypass grafting in 2 patients. Ring annuloplasty was performed in all patients. The median ring size was 30 mm (range 24-36 mm). On-table transoesophageal echocardiography post-repair showed mild residual MR in two patients and no MR in the remainder. There were no cases of systolic anterior motion. There was one re-exploration for bleeding. No patients required haemofiltration or suffered from stroke and deep sternal wound infections. There was no in-hospital mortality. At discharge mean left ventricular (LV) end-diastolic diameter was 4.8 ± 0.7 cm compared with 5.6 ± 0.7 cm pre-operatively (P < 0.005), while mean LV end-systolic diameter was 3.2 ± 0.8 cm when compared with 4.0 ± 0.7 cm pre-operatively (P < 0.005). The mean LA size was 5.2 ± 1.0 cm when compared with 6.1 ± 1.6 cm pre-operatively (P = 0.03). There was mild MR in two patients, but none in the rest. The mean MV area was 3.0 ± 0.7 cm(2). The mean systolic pulmonary artery pressure was 40.4 ± 15.5 mmHg when compared with 54.1 ± 12.2 mmHg pre-operatively (P = 0.02). Seventeen patients (85%) were in NYHA class I/II at latest follow-up (P < 0.0001 vs pre-operatively). During follow-up, there were no thrombo-embolic complications, re-operation, endocarditis or deaths.
Conclusions: MV annuloplasty for annular dilatation secondary to AF has a good mid-term outcome.