Siham Lazam

Natural History of Paradoxical Low-Gradient Severe Aortic Stenosis

Background—Up to 30% of patients with severe aortic stenosis (SAS; indexed aortic valve area <0.6 cm2/m2) present with low transvalvular gradient despite a normal left ventricular ejection fraction. Presently, there is intense controversy as to the prognostic implications of such findings. Accordingly, the aim of the present work was to compare the natural history of patients with paradoxical low-gradient (PLG) or high-gradient (HG) SAS. Methods and Results—We prospectively studied 349 patients with SAS and preserved left ventricular ejection fraction. Patients were categorized into HG-SAS (n=144) and PLG-SAS (n=205) according to mean transvalvular gradient (mean gradient >40 or ⩽40 mm Hg). Primary end points were all-cause mortality and echocardiographic disease progression. To evaluate natural history, patients undergoing aortic valve replacement were censored at the time of surgery (n=92). During a median follow-up of 28 months, 148 patients died. Kaplan–Meier survival curves showed better survival in PLG-SAS than in HG-SAS, both in the overall population (48% versus 31%; P<0.01) and in the asymptomatic subgroup (59% versus 35%; P<0.02). In asymptomatic patients, Cox analysis identified age, diabetes mellitus, left atrial volume, and mean gradient as independent predictors of death. Finally, at last echocardiographic follow-up, PLG-SAS demonstrated significant increases in mean gradient (from 29±6 to 38±11 mm Hg; P<0.001). Conclusions—Our study indicates that PLG-SAS is a less malignant form of AS compared with HG-SAS, because their spontaneous outcome is better. We further demonstrated that patients with PLG-SAS are en route toward the more severe HG-SAS form, because the majority of them evolve into HG-SAS over time.

Twenty-Year Outcome after Mitral Repair Versus Replacement for Severe Degenerative Mitral Regurgitation. Analysis of a Large, Prospective, Multicenter International Registry.

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.

0411 : Aortic valve is less severely affected in paradoxical low gradient than in high gradient severe aortic stenosis

Background Paradoxical low gradient (PLG) severe aortic stenosis (SAS) is a recently described subset of SAS, which is a matter of intense debate. Some authors indeed consider this new entity as a more advanced form of SAS, whereas others believe the opposite. To get further insight into the pathophysiology of PLG SAS, we compared the weight of the valves explanted at the time of surgery (AVR) and the degree of valve calcification among consecutive patients with PLG SAS and high-gradient (HG) SAS. Methods We prospectively recruited 38 consecutive patients (20 men; mean age: 73 yrs) with isolated non-rheumatic SAS (indexed aortic valve area (AVAi) Results PLG and HG SAS had similar baseline characteristics with the exception of AVAi which was higher (0.44±0.06 vs 0.36±0.10 cm2m2, p=0.008) and MG which was lower (32±7 vs 55±12 mmHg, p 0.90) and in-vivo (r2=0.71) Agatston scores. Interestingly, valves explanted from patients with PLG SAS were lighter (1.58±0.65 vs 2.65±1,24g, p=0.001) and showed lower ex-vivo Agatston scores (363±282 vs 1211±840, p Conclusion The valves weight and degree of valve calcification reported in our study indicate that PLG SAS valves are less severely affected than HG SAS valves. These data thus reinforce the hypothesis that PLG SAS is a lesser advanced form of aortic stenosis than HG SAS.

0414 : Very long term survival after mitral repair vs replacement. A propensity score analysis of a large, prospective, multicenter international registry

Background Despite the absence of randomized studies comparing mitral valve (MV) repair and replacement, international guidelines strongly recommend MV repair as the optimal surgical treatment for severe degenerative mitral regurgitation (dMR). Yet, the level of evidence supporting these recommendations is low, owing to the lack of available clinical trial data. In this context, analysis of large multicenter registries becomes critical. Objective To compare very long-term survival among patients (pts) undergoing MV repair versus replacement for the treatment of severe dMR using the technique of propensity score (PS) matching to reduce bias in nonrandomized cohorts. Methods The Mitral Regurgitation International DAtabase (MIDA) is a prospective multicenter registry that includes 2,569 consecutive pts with dMR, who were recruited in 6 tertiary centers (France, Italy, Belgium, and the United States) between 1980 and 2005. Among these, we identified 1,922 pts who underwent mitral surgery, including 1,709MV repairs and 213MV replacements. We compared operative mortality and overall survival in both the entire study population and in 615 PS-matched (2:1) pts. Results Operative mortality was lower after MV repair than after MV replacement, both in the entire population (2 vs 7%; p=0.001) and in the PSmatched pts (4 vs 8%; p=0.04). Similarly, 20-year survival was better after MV repair than after MV replacement, both in the entire population (46% [(95% CI, 39%-52%] vs 23% [95% CI, 14%-32%], p Conclusions Among registry pts with dMR, performance of MV repair resulted in lower operative mortality and greater long-term survival compared to MV replacement, thus supporting current international recommendations.

0294: Extravascular volume by cardiac MR T1 mapping accurately predicts histologically measured fibrosis in valve disease

Background Valvular heart disease is associated with left ventricular hypertrophy, remodeling and development of diffuse interstitial fibrosis. So far, histopathology remains the gold standard for evaluating diffuse myocardial fibrosis. Gadolinium enhanced Cardiac Magnetic Resonance (CMR) T1 mapping is new method which allows to quantify the myocardial extracellular volume (ECV). Hence, it was suggested that this ECV measurements allows to non-invasive estimate diffuse fibrosis. However validations studies are scars. Therefore the aim of this study was to validate measurements of ECV by T1-Modified Lock-locker (MOLLI) CMR against histological measurement. Methods and results Between June 2012 and September 2013, 15 patients (age=57±15 years, 73% men) with either severe aortic valve disease (stenosis or regurgitation) or severe mitral regurgitation, but without coronary artery disease preoperatively underwent ECV measurement by CMR MOLLI T1 mapping. LV biopsies were performed at the time of surgery 7±8 days later and stained with Sirius red. The amount of fibrosis quantified by biopsy was 6.6±4.8% [2.1;15.9]. ECV by T1 mapping was 28.3±4.7% [23.3;38.6] (values are presented as mean±SD [min;max]). There was a good correlation between histologically measured fibrosis and T1 mapping ECV (r=0.77, p Conclusion ECV determined by CMR T1 mapping closely correlates with histologically determined diffuse interstitial fibrosis and could thus be used to non-invasively quantify interstitial fibrosis in patients with heart diseases.