Mitral annular reduction with subablative therapeutic ultrasound: pre-clinical evaluation of the ReCor device

• Published in: EuroIntervention Vol. 6; no. 1; pp. 54 - 62
• Main Authors: JILAIHAWI, Hasan, VIRMANI, Renu, BONAN, Raoul, NAKAGAWA, Hiroshi, DUCHARME, Anique, SHI, Yan-Fen, CARTER-MONROE, Naima, LADICH, Elena, IYER, Mano, IKEDA, Atsushi, ASGAR, Anita
• Format: Journal Article
• Language: English
• Published: Toulouse Société Europa Edition 01-05-2010
• Subjects: Animals; Biological and medical sciences; Cardiology. Vascular system; Catheter Ablation - instrumentation; Dogs; Echocardiography, Doppler; Elastin - metabolism; Endocardial and cardiac valvular diseases; Equipment Design; Feasibility Studies; Fibrillar Collagens - ultrastructure; Heart; Materials Testing; Medical sciences; Microscopy, Electron, Transmission; Mitral Valve - diagnostic imaging; Mitral Valve - metabolism; Mitral Valve - surgery; Mitral Valve - ultrastructure; Models, Animal; Radiography, Interventional; Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects); Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Time Factors; Ultrasonic Therapy - instrumentation; Evaluation; Mitral valve; Device; Ultrasonic treatment; Instrumentation therapy; Cardiovascular disease; Plasty; Reduction; valvuloplasty; Cardiac valvular disease; Surgery; valvular heart disease; Mitral valve disease
• ISSN: 1774-024X; 1969-6213
• DOI: 10.4244/EIJV6I1A9

To evaluate the potential for mitral annular (MA) size reduction using a novel device utilising therapeutic ultrasound (TU).
The ReCor device (ReCor Medical, Inc., Ronkonkoma, NY, USA, Investigational device, not for use in human application) was studied in a closed chest canine animal model (35 dogs). Under fluoroscopy, a 12 Fr TU balloon catheter was advanced into the left atrium (transseptal approach). The TU balloon was inflated with contrast-saline, positioned at the MA and energy delivered circumferentially, to heat the tissue locally. Five TU applications were delivered (at least 60W for at least 40 sec). Relative to baseline, mitral valve annular diameter reduction (measured by transthoracic echocardiography) was 8.4% immediately post procedure(p<0.001), 8.6% at one week (p<0.001), 8.8% at two weeks (p<0.001), 9.3% at three weeks (p<0.001), 10.8% at four weeks (p<0.001), 8.6% at three months (p<0.001) and 5.7% at six months (p<0.001). Histology showed an increase in elastin associated with tissue thickening at the annular level. Transmission electron microscopy demonstrated a decrease in diameter of individual collagen fibres in treated regions compared to controls.
Therapeutic ultrasound (TU) energy application to the mitral annulus is feasible percutaneously. A reduction in annular dimensions occurs immediately and appears to be durable without peri-annular damage.