Effects of laser thermal angioplasty on arterial contractions and mechanics

In each of 8 rabbits, a fiberoptic with a 1.5 mm diameter metal tip was inserted into the abdominal aorta. After preheating with 8-10 watts of argon laser energy, the metal tip was passed through the external iliac artery. Thermal injury was evaluated by histology and by measuring arterial contractions and wall mechanics. The contralateral iliac artery was used as a control. Laser thermal angioplasty (LTA) produced foci of coagulation necrosis, medial thinning, and wall rupture. Concomitantly, maximal arterial contractile force was reduced by 80% (p less than 0.01) and arterial wall stiffness was decreased (p less than 0.05). These changes may have clinical implications with regard to the incidence and severity of vasospasm and restenosis following angioplasty.