title: Annulus upsizing for mitral valve re-replacement in children.
abstract: BACKGROUND
  Mitral valve replacement remains the last resort for treatment of congenital mitral valve disease. Enlarging the mitral annulus at the time of mitral valve replacement may allow implantation of a larger prosthesis in children.
  
  
  METHODS
  All mitral valve replacement procedures from 1990 to 2012 were included, and mitral annulus enlargement techniques were analyzed. A control group of patients undergoing replacement of a previously implanted mechanical mitral valve prosthesis was compared with the cohort of patients who underwent annular enlarging procedures. Primary end points were increases in annulus size and Z score, and freedom from paced rhythm.
  
  
  RESULTS
  Among 205 mitral valve replacement procedures, 16 (8%) included techniques to upsize the mitral annulus in 15 patients, all but 1 of whom had undergone prior mitral valve replacement. These patients were compared with a control cohort of 53 patients undergoing mitral valve re-replacement without annulus enlargement. The annulus was upsized by 18% ± 11% (compared with 16% ± 20% in controls, P = .5) using open balloon dilation in 4 patients, radial annular incisions in 5 patients, and patch augmentation of the aorto-mitral continuity in 7 patients. The mean valvar diameter Z score increased from -0.2 ± 1.3 to +1.1 ± 1.4 (P < .001), compared with an increase from -0.3 ± 1.2 to 0.9 ± 1.1 in controls (P < .001). During a mean follow-up of 6.5 ± 6.4 years, 4 of 12 patients required permanent pacing in the upsizing group (predominantly with patch augmentation), versus 5 of 53 patients in the control group.
  
  
  CONCLUSIONS
  In children undergoing mitral valve replacement, various techniques can be used to upsize the mitral annulus and allow implantation of a larger prosthesis. There is a nontrivial risk of heart block with annulus upsizing, which deserves further study.
authors.affiliation: Department of Cardiac Surgery, Children's Hospital Boston & Harvard Medical School, Boston, Mass 02445, USA. Patrick.Myers@hcuge.ch
authors.forename: Patrick O
authors.initials: PO
authors.lastname: Myers
authors.forename: Pedro J
authors.initials: PJ
authors.lastname: del Nido
authors.forename: Doff B
authors.initials: DB
authors.lastname: McElhinney
authors.forename: Zain
authors.initials: Z
authors.lastname: Khalpey
authors.forename: James E
authors.initials: JE
authors.lastname: Lock
authors.forename: Christopher W
authors.initials: CW
authors.lastname: Baird
mesh_terms: D000293:Adolescent; D002304:Cardiac Pacing, Artificial; D016009:Chi-Square Distribution; D002648:Child; D002675:Child, Preschool; D018572:Disease-Free Survival; D005260:Female; D006327:Heart Block / Q000209:etiology / Q000628:therapy; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects / Q000295:instrumentation* / Q000401:mortality; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008943:Mitral Valve / Q000000981:diagnostic imaging / Q000254:growth & development / Q000601:surgery*; D011474:Prosthesis Design; D012086:Reoperation; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome; D014463:Ultrasonography; D055815:Young Adult
keywords: 20.1; 35.4; MVR; mitral valve re-replacement; mitral valve replacement; reMVR