Enhanced laser thrombolysis with photomechanical drug delivery: an in vitro study.
OBJECTIVE
Current techniques for laser thrombolysis are limited because they can not completely clear thrombotic occlusions in arteries, typically leaving residual thrombus on the walls of the artery. The objective of this study was to investigate the possibility of using photomechanical drug delivery to enhance laser thrombolysis by delivering drugs into mural thrombus during laser thrombolysis.


METHODS
Three experimental protocols were performed in vitro to quantitatively compare the effectiveness of thrombolysis by 1) constant infusion of drug, 2) laser thrombolysis, and 3) photomechanical drug delivery. A fiber-optic flushing catheter delivered drug (a solution of 1 microm fluorescent microspheres) and light ( a 1 micros pulsed dye laser) into a gelatin-based thrombus model. The process of laser-thrombus interaction was visualized using flash photography and the laser-induced pressure waves were measured using an acoustic transducer.


RESULTS
Lumen sizes generated by mechanically manipulating the catheter through the thrombus were smaller than those generated by laser ablation. The microspheres could be driven several hundred microns into the mural thrombus.


CONCLUSIONS
Photomechanical drug delivery has potential for enhancement of laser thrombolysis. Two mechanisms seem to be involved in photomechanical drug delivery: 1) mural deposition of the drug at the ablation site and 2) increased exposure of the thrombus surface area to the drug.
Oregon Medical Laser Center, Portland 97225, USA.
H Q
HQ
Shangguan
K W
KW
Gregory
L W
LW
Casperson
S A
SA
Prahl
D000162:Acoustics / Q000295:instrumentation; D002404:Catheterization / Q000295:instrumentation; D016503:Drug Delivery Systems; D005336:Fiber Optic Technology / Q000295:instrumentation; D005343:Fibrinolytic Agents / Q000008:administration & dosage*; D005456:Fluorescent Dyes; D005780:Gelatin; D006801:Humans; D007261:Infusions, Intra-Arterial; D053685:Laser Therapy / Q000295:instrumentation / Q000379:methods*; D008863:Microspheres; D008953:Models, Anatomic; D055100:Optical Fibers; D010781:Photography; D011312:Pressure; D015912:Thrombolytic Therapy / Q000379:methods*; D013927:Thrombosis / Q000188:drug therapy*; D014159:Transducers; D014753:Vinyl Compounds
D005343:Fibrinolytic Agents; D005456:Fluorescent Dyes; D014753:Vinyl Compounds; C007384:1,1-difluoroethylene; D005780:Gelatin