The vascular response induced by transmyocardial laser revascularization is determined by the size of the channel scar: Results of CO2, holmium and excimer lasers.
OBJECTIVE
To investigate the angiogenic effect of CO2, Ho:YSGG, and XeCl excimer TMLR in a rat model with morphologic characteristics of chronic myocardial ischemia.


METHODS
Two channels (200-320 microm) were created per rat heart. After 14 days, vessel numbers and densities in and around laser scars were assessed.


RESULTS
Capillary densities in the laser scars were equal between the three lasers ( approximately 130 vessels/mm2) but much lower than in control areas ( approximately 2,100 vessels/mm2). Vessel densities excluding capillaries were significantly higher in Ho:YSGG and CO2 scars compared to excimer scars, while only Ho:YSGG scars contained significantly more large vessels (diameter > or = 20 microm) than control areas. Only rarely, extension of vascular growth into adjacent myocardium was observed in any of the three groups.


CONCLUSIONS
These results indicate that the angiogenic response following TMLR is limited to the channel scar and related to the scar size rather than the specific laser type.
Huikeshoven
Menno
M
Laser Center, Academic Medical Center, University of Amsterdam, The Netherlands. m.huikeshoven@amc.uva.nl
Beliën
Jeroen A M
JA
Tukkie
Raymond
R
Beek
Johan F
JF
D000818:Animals; D002245:Carbon Dioxide; D002921:Cicatrix / Q000473:pathology*; D003331:Coronary Vessels / Q000473:pathology*; D006695:Holmium; D053685:Laser Therapy; D008297:Male; D017202:Myocardial Ischemia / Q000601:surgery*; D009204:Myocardial Revascularization / Q000379:methods*; D018919:Neovascularization, Physiologic; D051381:Rats; D011918:Rats, Inbred SHR
D002245:Carbon Dioxide; D006695:Holmium