Does laser injury induce a different neovascularisation pattern from mechanical or ischaemic injuries?

AIM To analyse the arteriolar pattern of laser induced channels and their surroundings compared with mechanical and ischaemic injury. METHODS 24 pigs were randomised to a myocardial infarction group, a transmyocardial laser revascularisation group, a needle group, or a control group. In the laser revascularisation and needle groups, five channels were created either with a 1.75 mm probe holmium-YAG laser or a Tru-cut needle of the same size. Animals were killed 28 days later. Morphometric analysis of vascular density was expressed as the mean (SD) number of arteriolar structures/cm2. RESULTS Laser and needle channels were completely invaded by granulation tissue. Their surface areas did not differ significantly: 2.28 (0.7) mm2 and 2.38 (1.1) mm2, respectively (p = 0.82). Within both types of channel, arteriolar density was significantly increased in comparison with the myocardial infarction scar: 197 (52)/cm2 and 190 (64)/cm2, respectively (p = 0.8) versus 56 (20)/cm2 (p