Vascular recanalization with the argon laser: the role of blood in the transmission of laser energy.

Successful revascularization of stenosed arteries with the argon laser optical fiber catheter requires delivery of high-power-density energy to the lesion. Because of the high energy absorption by hemoglobin at the argon laser wavelengths, which would attenuate transmission of laser energy to the obstruction, we measured argon laser transmission through blood at different concentrations. We found that no transmission occurred through 1 mm of whole blood with hematocrit of 42 and that blood must be diluted to a hematocrit below 1 for laser energy to be delivered. Successful use of the intravascular argon laser is dependent on the creation of a transmission medium by displacement of blood by saline or other non-absorbing substance.