Laser-assisted thermal angioplasty in human peripheral artery occlusions: Mechanism of recanalization

Abstract

Recanalization of completely occluded superficial femoral or popliteal arteries was attempted in 18 patients with use of an Argon laser-mediated thermal probe. The length of the occluded segments varied between 0.5 and 26.0 cm, but 67% of the occlusions were greater than 9 cm long. The initial success rate was 67%. Arterial perforation occurred in six patients but was not associated with major complications. To study the mechanism of the laser-mediated thermal probe, thermal recanalization was performed on 11 human arterial segments in vitro obtained after amputation, and mechanical recanalization was performed in vitro in 10 human peripheral arteries with use of a guide wire and catheter technique. An additional four arteries were studied with the laser probe as a non-heated mechanical device. Both the mechanical and thermal devices appear to follow a similar pathway through a complete obstruction. These studies suggest that the thermal probe burns through soft fibrous tissue but is mechanically deflected away from hard fibrocalcific plaque. The probe then advances along the plane between the intimal plaque and the media for a variable length before perforating through the adventitia. These observations suggest that the major mechanism of thermal probe recanalization may be a mechanical process. It appears that thermal probe devices do not inherently seek the true lumen of an occluded artery and that better guidance systems need to be developed.

Design and evaluation of a fiberoptic fluorescence guided laser recanalization system

“…On the other hand, most occlusions are due to white fibrous or fibrocalcific plaque which are detected with a high degree of sensitivity by fluorescence spectroscopy [47,481. It is interesting to note that the recanaliza-tion channel through the occluded arterial segments was often centrally located. This is in contrast to the findings of Tobis et al [49] that mechanical and thermal recanalization devices appear to follow a recanalization path along the plane between the intimal plaque and the media. Fluorescence spectroscopy guidance that necessitated redirection of the fiberoptic when media fluorescence was detected may have enabled a more centrally located recanalization channel.…”

Balloon angioplasty of totally and subtotally occluded coronary arteries: results using the hydrophillic terumo radifocus guidewire m (glidewire)

“…These complex plaques are characterised by a thin fibrous cap overlying soft atheromatous debris. It has been shown that the path of recanalisation of these total occlusions may just as easily be through the soft atheromatous debris after the thin fibrous cap has been ruptured or crossed during gentle probing, as through the true lumen occluded by thrombus [23]. The stiff nature of the Terumo shaft, associated with its ability to seek the path of least resistance due to its hydrophilicity, may contribute to its ability to cross such lesions when fibrocellular organisation of the thrombus has already occured.…”

Thermal Laser Angioplasty of the Lower Extremities: Comparison of Early and Late Experience

“…Additionally, the delegation of this procedure to a few physicians, to surpass the learning curve, is of inestimatable importance. 2,7 Certainly, this aspect has contributed to improvement in our procedural success and complication rates despite tackling longer lesions in our later experience.…”