Photoangioplasty - An emerging clinical cardiovascular role for photodynamic therapy

Photodynamic therapy (PDT) has been studied and applied to various disease processes. The potential of PDT for selective destruction of target tissues is especially appealing in cardiovascular disease, in which other existing interventional tools are somewhat nonselective and carry substantial risk of damage to the normal arterial wall. Enthusiasm for photoangioplasty (PDT of vascular de novo atherosclerotic and, potentially, restenotic lesions) is fueled by more effective second-generation photosensitizers and technolo gical advances in endovascular light delivery. This excitement revolves aro und at least 4 significant attributes of light-activated therapy: the putat ive selectivity and safety of photoangioplasty, the potential for atraumati c and effective debulking of atheromatous plaque through a biological mecha nism, the postulated capability to reduce or inhibit restenosis, and the po tential to treat long segments of abnormal vessel by simply using fibers wi th longer light-emitting regions. The available nonclinical data, coupled w ith the observations of a new phase I trial in human peripheral atheroscler osis, suggest a promising future for photoangioplasty in the treatment of p rimary atherosclerosis and prevention of restenosis.