title: Excimer versus carbon dioxide transmyocardial laser revascularization: effects on regional left ventricular function and perfusion.
abstract: BACKGROUND
  Transmyocardial laser revascularization (TMR) has been established with the carbon dioxide (CO2) laser. The largely unstudied excimer laser creates channels through chemical bond dissociation instead of thermal ablation, thereby avoiding thermal injury. We sought to compare the effects of CO2 and excimer TMR in a porcine model of chronic ischemia.
  
  
  METHODS
  Pigs underwent ameroid constrictor placement on the circumflex artery to create chronic ischemia. TMR was performed with CO2 (n = 8) or excimer (n = 8) laser 6 weeks later; controls (n = 7) had ameroid placement only. Regional myocardial blood flow (RMBF), determined by radioactive microspheres, and regional myocardial function, determined by percent segmental shortening (%SS), were assessed 18 weeks after ameroid placement.
  
  
  RESULTS
  Values are mean +/- SD. In the ischemic zone, RMBF (mL/min/g) was improved in the CO2 (0.73 +/- 0.19) and excimer (0.78 +/- 0.22) groups when compared with controls (0.55% +/- 0.12%, p < 0.05). %SS was also improved in the CO2 (15.2% +/- 5.5%) and excimer (15.3% +/- 5.1%) groups when compared with controls (8.0% +/- 4.2%, p < 0.05).
  
  
  CONCLUSIONS
  Excimer and CO2 TMR significantly improve RMBF and regional function in this porcine model of chronic myocardial ischemia despite fundamentally different tissue interactions.
authors.affiliation: Division of Cardiac Surgery, Harvard Medical School, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.
authors.forename: J S
authors.initials: JS
authors.lastname: Martin
authors.forename: U
authors.initials: U
authors.lastname: Sayeed-Shah
authors.forename: J G
authors.initials: JG
authors.lastname: Byrne
authors.forename: M H
authors.initials: MH
authors.lastname: Danton
authors.forename: K Q
authors.initials: KQ
authors.lastname: Flores
authors.forename: R G
authors.initials: RG
authors.lastname: Laurence
authors.forename: L H
authors.initials: LH
authors.lastname: Cohn
mesh_terms: D000818:Animals; D003326:Coronary Circulation / Q000502:physiology*; D003327:Coronary Disease / Q000503:physiopathology / Q000601:surgery*; D004867:Equipment Design; D006439:Hemodynamics / Q000502:physiology; D053685:Laser Therapy / Q000295:instrumentation*; D009204:Myocardial Revascularization / Q000295:instrumentation*; D013552:Swine; D016277:Ventricular Function, Left / Q000502:physiology*