Negative impact of atrial fibrillation and pulmonary hypertension after mitral valve surgery in asymptomatic patients with severe mitral regurgitation: a 20-year follow-up.

OBJECTIVES: The timing for mitral valve (MV) surgery in asymptomatic patients with severe mitral regurgitation (MR) and preserved left ventricular (LV) function remains controversial. We aimed at analysing the long-term outcome of asymptomatic patients with atrial fibrillation (AF) and/or pulmonary hypertension (PHT) after successful MV repair.

METHODS: From January 1992 to December 2012, 382 patients with severe degenerative MR, with no or mild symptoms, preserved LV function (ejection fraction > 60%) and LV systolic dimensions <45 mm were submitted to surgery and followed up for up to 22 years (3209 patient-years). Patients with associated surgeries, other than tricuspid repair, were excluded. Patients with AF and/or PHT (Group A; n = 106, 24.4%) were compared with patients without these comorbidities (Group B; n = 276, 63.6%). Propensity-score matching (for preoperative variables) was performed obtaining 102 patients in each arm. Survival and event-free survival [major cardiac and cerebrovascular events (MACCEs); freedom from mitral reoperation and recurrent moderate and severe MR] were analysed.

RESULTS: MV repair was performed in 98.2% of cases and tricuspid annuloplasty in 6.9%. Overall 30-day mortality was 0.8%, not different between groups, and absent in patients with isolated posterior leaflet prolapse (n = 211). Patients with AF/PHT had worse late survival by comparison with Group B patients (67.0 ± 7.4 vs 86.5 ± 3.9% at 15 years, P < 0.001), survival free from MACCE (52.7 ± 8.7 vs 74.5 ± 5.0%, P < 0.001), from recurrent moderate and severe MR (65.1 ± 10.3 vs 87.0 ± 3.8%, P = 0.002) and from mitral reoperation during the follow-up (87.3 ± 6.3 vs 94.2 ± 2.7%, P = 0.04). These differences were confirmed in the propensity score-matched population. Patients from Group A also displayed a lesser degree of reverse remodelling. There was a significant reduction in the systolic pulmonary artery pressure (SPAP) after surgery, more pronounced in Group A patients; nonetheless, the mean SPAP at late follow-up was higher in these patients (45 vs 30 mmHg).

CONCLUSIONS: MV repair can be achieved in the great majority of patients with degenerative regurgitation, with low mortality (<1%). Asymptomatic or mildly symptomatic patients with severe MR, preserved LV function and AF/PHT had poorer long-term survival and event-free survival even after a successful surgery. The durability of MV repair was also compromised in these patients, which indicates that they should have been operated earlier.