AbstractWe constructed a model of the human arterial circulation that can be used to test laser angioplasty catheters and techniques on obstructed human coronary arteries under simulated physiologic conditions of blood pressure and flow. In this model system, a balloon‐tipped catheter with a central, 0.02‐cm light fiber was used to deliver 4 W of laser energy to two obstructed human cadaver coronary artery segments and four normal dog femoral artery segments. Flushing the catheter with saline during the lases minimized lateral thermal tissue damage. Channels were created in the obstructed arteries that were twice the diameter of the light fiber used to lase. One of four dog arteries perforated, underscoring the potential hazards of the procedure and the need for laser catheters that are flexible and capable of precise alignm