Mechanical Mitral Valve Replacement: A Multicenter Study of Outcomes with Use of 15-17 mm Prostheses.

Background The aim of this study was to evaluate early and mid-term outcomes (mortality and prosthetic valve reintervention) after mitral valve replacement (MVR) with 15-17 mm mechanical prostheses. Methods A multicenter, retrospective cohort study was performed among patients who underwent MVR with a 15-17 mm mechanical prosthesis at 6 congenital cardiac centers: 5 in The Netherlands and 1 in the United States. Baseline, operative and follow-up data were evaluated. Results MVR was performed in 61 infants (15-mm: 17 (28%), 16-mm: 18 (29%), 17-mm: 26 (43%)) of whom 27 (47%) were admitted to the ICU prior to surgery and 22 (39%) required ventilator support. Median age at surgery was 5.9 (IQR 3.2-17.4) months and median weight was 5.7 (IQR 4.5-8.8) kg. There were 13 (21%) in-hospital deaths and 8 (17%, among 48 hospital survivors) late deaths. Major adverse events occurred in 34 (56%). Median follow-up was 4.0 (IQR 0.4 - 12.5) years. First prosthetic valve replacement (n=27 (44%)) occurred at median of 3.7 (IQR 1.9-6.8) years. Prosthetic valve endocarditis was not reported and there was no mortality related to prosthesis replacement. Other reinterventions included permanent pacemaker implantation (n=9 (15%)), subaortic stenosis resection (n=4 (7%)), aortic valve repair (n=3 (5%), and aortic valve replacement (n=6 (10%)). Conclusions Mitral valve replacement with a 15-17 mm mechanical prostheses is an important alternative to save critically ill neonates and infants in whom the mitral valve cannot be repaired. Prosthesis replacement for outgrowth can be carried out with low risk.