Extraluminal laser angioplasty (ELAN): a new method for treating atherosclerotic vessels

ELAN is a new method for treating atherosclerotic vessels. Its purpose is to restore wall flexibility by removing arterial wall tissue from the outer arterial layer. This leads to expansion of the narrowed vessel resulting in increased blood flow. We generated cuts in dissected arteries of sheep and pigs by photo-ablation with an ArF-Excimer Laser operating at a wavelength of 193 nm. During the cutting process the vessel diameter was monitored by measuring the running time of the laser induced pressure transients with a pressure transducer lying under the artery. A nearly linear increase of the diameter dependent on the residual wall thickness was found with a maximum increase of vessel diameter about 10%. We also observed that the arterial wall maintains stable to very small residual wall thicknesses i.e. deep cutting. To support the experiments and to test different geometries of tissue removal we performed FEM-Analysis. We simulated vessel deformation and the total strain depending on the depth, width and number of cuts in the outer artieral wall. We also found a significant increase of the "lumen" in a model with atherosclerotic shape obtained from a histological section.