The old spontaneously hypertensive rat as a model for transmyocardial laser revascularisation research

The vascular response induced by transmyocardial laser revascularization is determined by the size of the channel scar: Results of CO2, holmium and excimer lasers

BACKGROUND AND OBJECTIVES

To investigate the angiogenic effect of CO2, Ho:YSGG, and XeCl excimer TMLR in a rat model with morphologic characteristics of chronic myocardial ischemia.

STUDY DESIGN/MATERIALS AND 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.