ABSTRACT
Chronic total occlusions (CTO) of coronary and peripheral arteries are increasingly encountered in clinical practice as the procedural complexity increases and more patients are referred later in their clinical course for attempted revascularization. Laser therapy, in theory, is uniquely capable of approaching the complex lesions. The excimer laser, or the use of the excited dimer of xenon chloride, is the only system currently used clinically for vascular applications. The catheters and technique for performing laser atherectomy have significantly improved since its introduction in the late 1980s. The development of smaller more powerful lasers, delivering continuous energy, facilitates the ablative atherectomy required for treating longer more complex lesions and chronically occluded vessels. The laser has three mechanisms of tissue and thrombus ablation: photochemical, in which light breaks chemical bonds, photothermal, which occurs when the laser energy produces heat and photomechanical, when light directly produces mechanical energy.
