Objective: Develop a representative calcium target model to evaluate penetration of calcified plaque lesions during
atherectomy procedures using 308 nm Excimer laser ablation.
Materials and Methods: An in-vitro model representing human calcified plaque was analyzed using Plaster-of-Paris and
cement based composite materials as well as a fibrinogen model. The materials were tested for mechanical consistency.
The most likely candidate(s) resulting from initial mechanical and chemical screening was submitted for ablation testing.
The penetration rate of specific multi-fiber catheter designs and a single fiber probe was obtained and compared to that
in human cadaver calcified plaque. The effects of lasing parameters and catheter tip design on penetration speed in a
representative calcified model were verified against the results in human cadaver specimens.
Results: In Plaster of Paris, the best penetration was obtained using the single fiber tip configuration operating at 100
Fluence, 120 Hz. Calcified human lesions are twice as hard, twice as elastic as and much more complex than Plaster of
Paris. Penetration of human calcified specimens was highly inconsistent and varied significantly from specimen to
specimen and within individual specimens.
Conclusions: Although Plaster of Paris demonstrated predictable increases in penetration with higher energy density and
repetition rate, it can not be considered a totally representative laser ablation model for calcified lesions. This is in part
due to the more heterogeneous nature and higher density composition of cadaver intravascular human calcified
occlusions. Further testing will require a more representative model of human calcified lesions.