Szymanski, Catherine

Background: Mitral valve (MV) repair is preferred over replacement in clinical guidelines and is an important determinant of the indication for surgery in degenerative mitral regurgitation. However, the level of evidence supporting current recommendations is low, and recent data cast doubts on its validity in the current era. Accordingly, the aim of the present study was to analyze very long-term outcome after MV repair and replacement for degenerative mitral regurgitation with a flail leaflet. Methods: MIDA (Mitral Regurgitation International Database) is a multicenter registry enrolling patients with degenerative mitral regurgitation with a flail leaflet in 6 tertiary European and US centers. We analyzed the outcome after MV repair (n=1709) and replacement (n=213) overall, by propensity score matching, and by inverse probability-of-treatment weighting. Results: At baseline, patients undergoing MV repair were younger, had more comorbidities, and were more likely to present with a posterior leaflet prolapse than those undergoing MV replacement. After propensity score matching and inverse probability-of-treatment weighting, the 2 treatments groups were balanced, and absolute standardized differences were usually <10%, indicating adequate match. Operative mortality (defined as a death occurring within 30 days from surgery or during the same hospitalization) was lower after MV repair than after replacement in both the entire population (1.3% versus 4.7%; P <0.001) and the propensity-matched population (0.2% versus 4.4%; P <0.001). During a mean follow-up of 9.2 years, 552 deaths were observed, of which 207 were of cardiovascular origin. Twenty-year survival was better after MV repair than after MV replacement in both the entire population (46% versus 23%; P <0.001) and the matched population (41% versus 24%; P <0.001). Similar superiority of MV repair was obtained in patient subsets on the basis of age, sex, or any stratification criteria (all P <0.001). MV repair was also associated with reduced incidence of reoperations and valve-related complications. Conclusions: Among patients with degenerative mitral regurgitation with a flail leaflet referred to mitral surgery, MV repair was associated with lower operative mortality, better long-term survival, and fewer valve-related complications compared with MV replacement.

Background— Ejection fraction (EF) as a marker of left ventricular (LV) dysfunction and the appropriate thresholds for diagnosing severe or mild/moderate LV dysfunction in mitral regurgitation are doubted and poorly followed in clinical practice. We aimed at assessing the role of EF in a large registry of organic mitral regurgitation to objectively establish thresholds for various degrees of LV dysfunction and to analyze whether mitral surgery remains beneficial in those subsets of patients. Methods and Results— We investigated the relation between EF and mortality in 1875 patients with mitral regurgitation due to flail leaflets in sinus rhythm (65±13 years; median EF, 66% [60%–71%]) enrolled in the Mitral Regurgitation International Database (MIDA) registry. With EF <60%, mortality after diagnosis increased precipitously under medical management (adjusted hazard ratio [HR], 1.59 [1.19–2.12]) and during the entire follow-up (adjusted HR, 1.51 [1.22–1.87]). Severe LV dysfunction, if defined by EF <30%, would affect a minuscule number of patients (0.3%). Conversely, EF <45% was more frequent (2.9%) and was associated with considerable mortality under medical management (adjusted HR, 2.43 [1.50–3.95]) and during the entire follow-up (adjusted HR, 2.46 [1.67–3.61]). The group with EF of 45% to 60% represented a large proportion of patients (23%), exhibited rarely overt symptoms, and had higher mortality compared with EF >60%. Above 60%, no EF threshold further determined survival. The benefit of surgery remained considerable in the groups with EF <45% (adjusted HR, 0.28 [0.17–0.56]) and with EF of 45% to 60% (adjusted HR, 0.34 [0.21–0.64]). Conclusions— EF is valuable in defining presence and severity of LV dysfunction in organic mitral regurgitation. Patients with EF <45% have severe LV dysfunction, catastrophic outcome under medical management, and should not be denied surgery. Although there is no survival gain with EF ranges >60%, with EF dropping <60%, mortality increases precipitously and prompt surgical referral is critical to outcome.

Background— Left atrium (LA) enlargement is common in organic mitral regurgitation (MR) and is an emerging prognostic indicator. However, outcome implications of LA enlargement have not been analyzed in the context of routine clinical practice and in a multicenter study. Methods and Results— The Mitral Regurgitation International DAtabase (MIDA) registry enrolls patients with organic MR due to flail leaflets, diagnosed in routine clinical practice, in 5 US and European centers. We investigated the relation between LA diameter and mortality under medical treatment and after mitral surgery in 788 patients in sinus rhythm (64±12 years; median LA, 48 [43 to 52] mm). LA diameter was independently associated with survival after diagnosis (hazard ratio, 1.08 [1.04 to 1.12] per 1 mm increment). Compared with patients with LA <55 mm, those with LA ≥55 mm had lower 8-year overall survival ( P <0.001). LA ≥55 mm independently predicted overall mortality (hazard ratio, 3.67 [1.95 to 6.88]) and cardiac mortality (hazard ratio, 3.74 [1.72 to 8.13]) under medical treatment. The association of LA ≥55 mm and mortality was consistent in subgroups. Similar excess mortality associated with LA ≥55 mm was observed in asymptomatic and symptomatic patients ( P for interaction, 0.77). In patients who underwent mitral surgery, LA ≥55 mm had no impact on postoperative outcome ( P >0.20). Mitral surgery was associated with greater survival benefit in patients with LA ≥55 mm compared with LA <55 mm ( P for interaction, 0.008). Conclusions— In MR caused by flail leaflets, LA diameter ≥55 mm is associated with increased mortality under medical treatment, independent of the presence of symptoms or left ventricular dysfunction.