title: Resection of calcified aortic heart leaflets in vitro by Q-switched 2 µm microsecond laser radiation.
abstract: BACKGROUND
  Transcatheter aortic valve implantation (TAVI) can result in paravalvular leakage and stent deformation in the presence of severe calcification. This study was undertaken to determine the efficacy of laser-assisted resection of calcific aortic valve leaflets as a method to minimize the effects of calcium on perivalvular leakage during TAVI.
  
  
  METHODS
  A Q-switched Tm:YAG laser emitting at a wavelength of 2.01 μm was used to evaluate the cutting efficiency on highly calcified human aortic leaflets in vitro (N = 10). A pulse energy of 4.3 mJ, a pulse duration of 0.8-1 μs, and a repetition rate of 1 kHz were used. The radiation was transmitted via a 200 µm core diameter quartz fiber. Resection was performed in a fiber-tissue contact mode on water-covered samples in a dish. The remnant particles were analyzed with respect to quantity and size by light microscopy.
  
  
  RESULTS
  A resection rate of 40.4 ± 22.2 mg/min on highly calcified aortic leaflets was achieved. This corresponds to a cutting speed of approximately 1 cm/min; a laser dissection time of 3 min per leaflet is expected. The majority of the remnant particles (85.4%) were <6 μm in diameter, with only 0.1% exceeding 300 μm.
  
  
  CONCLUSIONS
  The Q-switched Tm:YAG laser system showed promising results in cutting calcified aortic valves, by transmitting sufficient energy through a small flexible fiber. Catheter-based removal of aortic valve calcification may help to improve TAVI technology.
authors.affiliation: Institute of Biomedical Optics, University of Lübeck, Lübeck, Germany.
authors.forename: I
authors.initials: I
authors.lastname: Rohde
authors.forename: J-M
authors.initials: JM
authors.lastname: Masch
authors.forename: D
authors.initials: D
authors.lastname: Theisen-Kunde
authors.forename: M
authors.initials: M
authors.lastname: Marczynski-Bühlow
authors.forename: R
authors.initials: R
authors.lastname: Bombien Quaden
authors.forename: G
authors.initials: G
authors.lastname: Lutter
authors.forename: R
authors.initials: R
authors.lastname: Brinkmann
mesh_terms: D001021:Aortic Valve / Q000473:pathology* / Q000601:surgery*; D001024:Aortic Valve Stenosis / Q000601:surgery*; D002114:Calcinosis / Q000601:surgery*; D019918:Heart Valve Prosthesis Implantation / Q000379:methods*; D006801:Humans; D066298:In Vitro Techniques; D053685:Laser Therapy / Q000379:methods*