title: Pulsed cavitational ultrasound for non-invasive chordal cutting guided by real-time 3D echocardiography.
abstract: OBJECTIVE
  Basal chordae surgical section has been shown to be effective in reducing ischaemic mitral regurgitation (IMR). Achieving this section by non-invasive mean can considerably decrease the morbidity of this intervention on already infarcted myocardium. We investigated in vitro and in vivo the feasibility and safety of pulsed cavitational focused ultrasound (histotripsy) for non-invasive chordal cutting guided by real-time 3D echocardiography.
  
  
  RESULTS
  Experiments were performed on 12 sheep hearts, 5 in vitro on explanted sheep hearts and 7 in vivo on beating sheep hearts. In vitro, the mitral valve (MV) apparatus including basal and marginal chordae was removed and fixed on a holder in a water tank. High-intensity ultrasound pulses were emitted from the therapeutic device (1-MHz focused transducer, pulses of 8 µs duration, peak negative pressure of 17 MPa, repetition frequency of 100 Hz), placed at a distance of 64 mm under 3D echocardiography guidance. In vivo, after sternotomy, the same therapeutic device was applied on the beating heart. We analysed MV coaptation and chordae by real-time 3D echocardiography before and after basal chordal cutting. After sacrifice, the MV apparatus were harvested for anatomical and histological post-mortem explorations to confirm the section of the chordae. In vitro, all chordae were completely cut after a mean procedure duration of 5.5 ± 2.5 min. The procedure duration was found to increase linearly with the chordae diameter. In vivo, the central basal chordae of the anterior leaflet were completely cut. The mean procedure duration was 20 ± 9 min (min = 14, max = 26). The sectioned chordae was visible on echocardiography, and MV coaptation remained normal with no significant mitral regurgitation. Anatomical and histological post-mortem explorations of the hearts confirmed the section of the chordae.
  
  
  CONCLUSIONS
  Histotripsy guided by 3D echo achieved successfully to cut MV chordae in vitro and in vivo in beating heart. We hope that this technique will open the door in the near future to the non-invasive treatment of functional IMR.
authors: Cardio-Vascular Departement, Hôpital Européen Georges Pompidou, Université Paris Descartes, UMR 970 Paris, France Institut Langevin, ESPCI, CNRS, Inserm U979, PSL Research University, France olivier.villemain@inserm.fr.
authors: Olivier
authors: O
authors: Villemain
authors: Institut Langevin, ESPCI, CNRS, Inserm U979, PSL Research University, France.
authors: Wojciech
authors: W
authors: Kwiecinski
authors: Cardiovascular Surgery, Hôpital Européen Georges Pompidou, Université Paris Descartes, Paris, France Laboratoire de recherches Biochirurgicales de la Fondation Alain Carpentier.
authors: Alain
authors: A
authors: Bel
authors: Institut Langevin, ESPCI, CNRS, Inserm U979, PSL Research University, France.
authors: Justine
authors: J
authors: Robin
authors: INSERM PARCC U970 Department of Pathology, Hôpital Européen Georges Pompidou, Université Paris Descartes, Paris, France.
authors: Patrick
authors: P
authors: Bruneval
authors: Institut Langevin, ESPCI, CNRS, Inserm U979, PSL Research University, France.
authors: Bastien
authors: B
authors: Arnal
authors: Institut Langevin, ESPCI, CNRS, Inserm U979, PSL Research University, France.
authors: Mickael
authors: M
authors: Tanter
authors: Institut Langevin, ESPCI, CNRS, Inserm U979, PSL Research University, France.
authors: Mathieu
authors: M
authors: Pernot
authors: Cardio-Vascular Departement, Hôpital Européen Georges Pompidou, Université Paris Descartes, UMR 970 Paris, France.
authors: Emmanuel
authors: E
authors: Messas
mesh_terms: D000818:Animals; D002815:Chordae Tendineae / Q000000981:diagnostic imaging / Q000601:surgery; D004195:Disease Models, Animal; D019560:Echocardiography, Three-Dimensional / Q000379:methods*; D066298:In Vitro Techniques; D019060:Minimally Invasive Surgical Procedures / Q000379:methods; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging* / Q000601:surgery*; D012680:Sensitivity and Specificity; D012756:Sheep; D059708:Ultrasonic Surgical Procedures / Q000379:methods*
keywords: mitral regurgitation; surgery; ultrasonics