I think it is similar to the laser sheaths used in the removal of chronically implanted pacemaker and ICD leads, only smaller. They remove the excess tissue causing the restenosis. As far as I know it is not widely used at most places or even at our institution.
Laser ablation
Lasers have been used to heat a catheter tip, to heat tissue abutting the angioplasty balloon, and to assist wire passage through chronic total occlusions, as well as for direct application to the lesion, for vaporizing tissue, and for direct application to myocardium.90–95 Similar to the atherectomy devices, laser phototherapy devices are intended to perform safe and effective lesion debulking and to reduce the thrombus burden. With the exception of severely calcified lesions and, perhaps, lesions with a heavy thrombus burden, laser therapy is similar to atherectomy in offering little benefit over balloon angioplasty because laser therapy increases the risk of procedural complications.85,87,93,96,97 Percutaneous transmyocardial laser revascularization yields no clinical improvement and promotes an additional risk of MI.95 Also as in rotational atherectomy, specific lesions or circumstances may warrant its use (Fig. 21-5).
http://cardiacsurgery.ctsnetbooks.org/cgi/content/full/3/2008/573?ck=nck#Atherectomy