title: Active mitral ring for post-surgical remote correction of residual mitral regurgitation on the beating heart.
abstract: OBJECTIVE
  Residual mitral regurgitation after valve repair worsens patients' clinical outcome. Postimplant adjustable mitral rings potentially address this issue, allowing the reshaping of the annulus on the beating heart under echocardiography control. We developed an original mitral ring allowing valve geometry remodelling after the implantation and designed an animal study to assess device effectiveness in correcting residual mitral regurgitation.
  
  
  METHODS
  The device consists of two concentric rings: one internal and flexible, sutured to the mitral annulus and a second external and rigid. A third conic element slides between the two rings, modifying the shape of the flexible ring. This sliding element is remotely activated with a rotating tool. Animal model: in adult swine, under cardio pulmonary bypass and cardiac arrest, we shortened the primary chordae of P2 segment to reproduce Type III regurgitation and implanted the active ring. We used intracardiac ultrasound to assess mitral regurgitation and the efficacy of the active ring to correct it.
  
  
  RESULTS
  Severe mitral regurgitation (3+ and 4+) was induced in eight animals, 54 ± 6 kg in weight. Vena contracta width decreased from 0.8 ± 0.2 to 0.1 cm; proximal isovelocity surface area radius decreased from 0.8 ± 0.2 to 0.1 cm and effective regurgitant orifice area decreased from 0.50 ± 0.1 to 0.1 ± 0.1 cm(2). Six animals had a reversal of systolic pulmonary flow that normalized following the activation of the device. All corrections were reversible.
  
  
  CONCLUSIONS
  Postimplant adjustable mitral ring corrects severe mitral regurgitation through the reversible modification of the annulus geometry on the beating heart. It addresses the frequent and morbid issue of recurrent mitral valve regurgitation.
authors: Department of Cardiovascular Surgery, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland. piergiorgio.tozzi@chuv.ch
authors: Piergiorgio
authors: P
authors: Tozzi
authors: Didier
authors: D
authors: Locca
authors: Fabrizio
authors: F
authors: Gronchi
authors: Daniel
authors: D
authors: Hayoz
authors: Enrico
authors: E
authors: Ferrari
authors: Ludwig K
authors: LK
authors: von Segesser
authors: Roger
authors: R
authors: Hullin
mesh_terms: D000818:Animals; D002315:Cardiopulmonary Bypass / Q000379:methods; D004195:Disease Models, Animal; D004452:Echocardiography / Q000379:methods; D006350:Heart Valve Prosthesis; D008943:Mitral Valve / Q000601:surgery; D008944:Mitral Valve Insufficiency / Q000503:physiopathology / Q000601:surgery / Q000628:therapy*; D009200:Myocardial Contraction / Q000502:physiology; D011184:Postoperative Period; D011474:Prosthesis Design; D013552:Swine
keywords: Echocardiography; Mitral regurgitation; Mitral valve repair; Valvuloplasty