Vascular Brachytherapy: A New Approach to Renal Artery In-Stent
Vascular Brachytherapy: A New Approach to Renal Artery In-Stent
Renovascular hypertension is frequently the result of atherosclerosis and has been successfully treated with percutaneous angioplasty. Stenting of vessels has helped to significantly lower the rate of restenosis after angioplasty; however, neointimal hyperplasia frequently results in growth of tissue through the stent, causing in-stent restenosis. Similar problems are seen in coronary stenting, and vascular brachytherapy has been shown to effectively prevent repeat in-stent restenosis. While coronary and renal restenoses occur by a common physiologic mechanism, their anatomic differences have prevented widespread adaptation of vascular brachytherapy to renal in-stent restenoses. A number of recent reports have demonstrated efficacy of renal vascular brachytherapy, but thus far, no large-scale, randomized data is available. Herein is reviewed the subject of renal vascular brachytherapy and the studies that are presently used in its justification.
Since the time of its introduction in 1978, percutaneous transluminal renal angioplasty (PTRA) has evolved into a major component of the management of renal artery stenosis. Part of this evolution has resulted from the introduction of metallic stents, which have aided in the durable maintenance of vessel patency. Nonetheless, similar to experiences in coronary stenting, stented renal arteries have been found to have a significant rate of in-stent restenosis (ISR). Dependent upon the study examined and, accordingly, the time of follow up, clinical or radiologic evidence of ISR in renal artery patients varies from 16–41%. Strongest predictors of ISR include a history of smoking, vessel diameter less than or equal to 4.0–4.5 mm and extended time of follow up. Extrapolating from coronary ISR data, additional predictors would include diabetes and lesion length.
Renovascular hypertension is frequently the result of atherosclerosis and has been successfully treated with percutaneous angioplasty. Stenting of vessels has helped to significantly lower the rate of restenosis after angioplasty; however, neointimal hyperplasia frequently results in growth of tissue through the stent, causing in-stent restenosis. Similar problems are seen in coronary stenting, and vascular brachytherapy has been shown to effectively prevent repeat in-stent restenosis. While coronary and renal restenoses occur by a common physiologic mechanism, their anatomic differences have prevented widespread adaptation of vascular brachytherapy to renal in-stent restenoses. A number of recent reports have demonstrated efficacy of renal vascular brachytherapy, but thus far, no large-scale, randomized data is available. Herein is reviewed the subject of renal vascular brachytherapy and the studies that are presently used in its justification.
Since the time of its introduction in 1978, percutaneous transluminal renal angioplasty (PTRA) has evolved into a major component of the management of renal artery stenosis. Part of this evolution has resulted from the introduction of metallic stents, which have aided in the durable maintenance of vessel patency. Nonetheless, similar to experiences in coronary stenting, stented renal arteries have been found to have a significant rate of in-stent restenosis (ISR). Dependent upon the study examined and, accordingly, the time of follow up, clinical or radiologic evidence of ISR in renal artery patients varies from 16–41%. Strongest predictors of ISR include a history of smoking, vessel diameter less than or equal to 4.0–4.5 mm and extended time of follow up. Extrapolating from coronary ISR data, additional predictors would include diabetes and lesion length.
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