Durability and Mechanisms of Failure of Barlow's Mitral Valve Repair
Georgina Rowe1, George Gill1, Amy Roach1, Dominic Emerson1, Wen Cheng1, Achille Peiris1, Asma Hussaini1, Natalia Egorova2, Joanna Chikwe1, Alfredo Trento1
1Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California, United States, 2Population and Health Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, United States
Objective: Barlow’s mitral valves present technical challenges that contribute to reduced reproducibility of repair. This study was therefore designed to evaluate predictors of complex repair and evaluate repair durability in Barlow’s mitral valve disease.
Methods: An institutional registry with prospective clinical, vital-statistics and echocardiographic follow-up was used to identify 855 consecutive patients undergoing robotic surgery for degenerative mitral regurgitation between 2005-2020, including 13% (n=111) with Barlow’s disease. Freedom from >2+ mitral regurgitation (MR) was analyzed with death as a competing risk and predictors of failure were analyzed using multivariate cox regression. Median follow-up was 5.5 years (range 0-15 years).
Results: Patients with Barlow’s disease were younger (median age 59 (interquartile range (IQR) 51-67) vs 62 (IQR 54-70, p=0.05), and more likely to be female (43.6% versus 30.7% p=0.01) than non-Barlow’s patients. Replacement was performed in 0.9% (n=1) of patients with Barlow’s disease and 0.8% (n=6) non-Barlow’s patients (p=1). Repair techniques are listed in Table 1: these comprised of triangular resection, chordae intervention, commissural closure or a combination of these techniques, completed with a true sized annuloplasty band in 94.5% of patients with Barlow’s disease. In Barlow’s patients 85.3% (n=64) of neochordae or chordal transfers were placed solely on the anterior leaflet, and additional techniques included sliding plasty (0.9% n=1) and quadrangular resection (4.5% n=5). Median annulopasty size was 39 (IQR 35-39), versus 35 (IQR 33-37) in non-Barlow’s patients (p<0.01). Barlow’s patients required significantly longer cardio-pulmonary bypass time (median 133 (IQR 117-149) versus 119 minutes (IQR 106-142) p<0.01). Second clamp times were required in 2.7% (n=3) Barlow’s patients and 1.9% (n=14) non-Barlow's patients (p=0.56). Freedom from > 2+ MR with death as a competing risk at 5 years was 91.5% (95% confidence interval (CI) 78.9-98%) in Barlow’s patients, and 95.8% (95% CI 92.8-97.8%) in non-Barlow’s patients (p=0.4). A total of 17 patients required mitral re-intervention at a median of 1.7 years (range 0.1-10.3 years), 23.5% (n=4) of these were Barlow’s patients. Predictors of late failure included anterior leaflet prolapse (hazard ratio (HR) 5.3, 95% CI 2.2-12.6) and Barlow’s disease (HR 4.2, 95% CI 1.8-10.1).
Conclusion: Anterior leaflet prolapse is associated with worse repair durability, independent of the presence of Barlow’s disease. This may have implications for the timing and choice of intervention in patients with severe mitral regurgitation due to Barlow’s disease and bileaflet prolapse without Class I indications for surgery.
Table 1: Patient characteristics, operative techniques and short-term outcomes stratified by mitral etiology
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