title: Descriptive Analysis of In Vitro Cutting of Swine Mitral Cusps: Comparison of High-Power Laser and Scalpel Blade Cutting Techniques.
abstract: OBJECTIVE
  The most common injury to the heart valve with rheumatic involvement is mitral stenosis, which is the reason for a big number of cardiac operations in Brazil. Commissurotomy is the traditional technique that is still widely used for this condition, although late postoperative restenosis is concerning. This study's purpose was to compare the histological findings of porcine cusp mitral valves treated in vitro with commissurotomy with a scalpel blade to those treated with high-power laser (HPL) cutting, using appropriate staining techniques.
  
  
  METHODS
  Five mitral valves from healthy swine were randomly divided into two groups: Cusp group (G1), cut with a scalpel blade (n = 5), and Cusp group (G2), cut with a laser (n = 5). G2 cusps were treated using a diode laser (λ = 980 nm, power = 9.0 W, time = 12 sec, irradiance = 5625 W/cm2, and energy = 108 J).
  
  
  RESULTS
  In G1, no histological change was observed in tissue. A hyaline basophilic aspect was focally observed in G2, along with a dark red color on the edges and areas of lower birefringence, when stained with hematoxylin-eosin, Masson's trichrome, and Sirius red. Further, the mean distances from the cutting edge in cusps submitted to laser application and stained with Masson's trichrome and Sirius red were 416.7 and 778.6 μm, respectively, never overcoming 1 mm in length.
  
  
  CONCLUSIONS
  Thermal changes were unique in the group submitted to HPL and not observed in the cusp group cut with a scalpel blade. The mean distance of the cusps' collagen injury from the cutting edge was less than 1 mm with laser treatment. Additional studies are needed to establish the histological evolution of the laser cutting and to answer whether laser cutting may avoid valvular restenosis better than blade cutting.
authors.affiliation: 1 Cardiovascular and Thoracic Surgery Department of The Heart Institute, General Hospital, Medical School, University of São Paulo , São Paulo, Brazil .
authors.forename: Nathali Cordeiro
authors.initials: NC
authors.lastname: Pinto
authors.affiliation: 1 Cardiovascular and Thoracic Surgery Department of The Heart Institute, General Hospital, Medical School, University of São Paulo , São Paulo, Brazil .
authors.forename: Pablo Maria Alberto
authors.initials: PM
authors.lastname: Pomerantzeff
authors.affiliation: 2 Post Graduate Program in Medicine and Biophotonics Applied to Health Sciences, University Nove de Julho , São Paulo, Brazil .
authors.forename: Alessandro
authors.initials: A
authors.lastname: Deana
authors.affiliation: 3 Nuclear and Energy Research Institute/Center for Lasers and Applications-IPEN/CLA, University of São Paulo , São Paulo, Brazil .
authors.forename: Denise
authors.initials: D
authors.lastname: Zezell
authors.affiliation: 3 Nuclear and Energy Research Institute/Center for Lasers and Applications-IPEN/CLA, University of São Paulo , São Paulo, Brazil .
authors.forename: Carolina
authors.initials: C
authors.lastname: Benetti
authors.affiliation: 4 Pathology Department of Heart Institute, Clinical Hospital, Medical School, University of São Paulo , São Paulo, Brazil .
authors.forename: Vera Demarchi
authors.initials: VD
authors.lastname: Aiello
authors.affiliation: 5 Research and Education Center for Phototherapy in Health Sciences , São Carlos, Brazil .
authors.forename: Luciana Almeida
authors.initials: LA
authors.lastname: Lopes
authors.affiliation: 1 Cardiovascular and Thoracic Surgery Department of The Heart Institute, General Hospital, Medical School, University of São Paulo , São Paulo, Brazil .
authors.forename: Fabio Biscegli
authors.initials: FB
authors.lastname: Jatene
authors.affiliation: 2 Post Graduate Program in Medicine and Biophotonics Applied to Health Sciences, University Nove de Julho , São Paulo, Brazil .
authors.forename: M Cristina
authors.initials: MC
authors.lastname: Chavantes
mesh_terms: D000818:Animals; D001707:Biopsy, Needle; D016009:Chi-Square Distribution; D004598:Electrosurgery / Q000295:instrumentation* / Q000379:methods; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D053685:Laser Therapy / Q000379:methods*; D008943:Mitral Valve / Q000473:pathology* / Q000601:surgery*; D023421:Models, Animal; D012680:Sensitivity and Specificity; D013552:Swine
keywords: commissurotomy; cusp; cutting; high-power laser; mitral valve; stenosis