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A novel platinum‐iridium, potentially gamma radioactive stent: Evaluation in a porcine model

In‐stent restenosis (ISR) is a major problem within stented arteries. Surface treatment of stents with platinum and gold were found to have the maximum charge with least neointima formation (NF). This study was designed to evaluate platinum (maximum electrical charge) as a material to make stents to reduce NF. Iridium was added to make an alloy suitable for stent manufacture, with the potential to make the stent radioactive. We implanted the novel platinum‐iridium (PI) stent in 10 porcine coronaries and compared to the Palmaz‐Schatz (PS) stent implanted in 8 coronary arteries. Six weeks after implantation, angiography of the stented vessel was performed before sacrifice. The coronaries were perfusion‐fixed and stained, and vessel parameters were analyzed by computer‐aided histomorphometry. The thrombus formation and the inflammatory response was less in the PI stent (0.04 ± 0.1 vs. 0.24 ± 0.2, P = 0.005; and 1.1 ± 0.5 vs. 2.4 ± 0.3, P < 0.001). The NF from PI‐stented arteries was smaller in size than the PS controls (1.9 ± 0.6 mm2 vs. 2.4 ± 0.4 mm2, P = 0.06). However, PI stents presented with higher recoil than the PS stent (16% vs. 5%, P < 0.001). Platinum‐iridium is a highly biocompatible material with high performance, low inflammatory response with small NF. This stent does not lead to thrombus formation and has the potential (due to the presence of iridium) to be irradiated to form a gamma radioactive stent. Cathet. Cardiovasc. Intervent. 51:364–368, 2000.

Optimal dosing of intravascular low-power red laser light as an adjunct to coronary stent implantation: insights from a porcine coronary stent model.

BACKGROUND It is believed that restenosis following coronary interventions is the result of endothelial denudation that leads to thrombus formation, vascular remodeling, and smooth muscle cell proliferation. Low-power red laser light (LPRLL) irradiation enhances endothelial cell growth in vitro and in vivo, and reduces restenosis in animal models. The present study investigated the optimal dose of intravascular LPRLL therapy in the prevention of in-stent stenosis in a porcine coronary stent model. METHODS AND RESULTS Selected right coronary artery segments were pretreated with a LPRLL balloon, delivering a dose of 0 mW during 1 min (group 1, n = 10), 50 mW during 1 min (group II, n = 10), or 100 mW during 1 min (group III, n = 10) before stenting. Quantitative coronary analysis of the stented vessel was performed before stenting, immediately after stenting, and at 6 weeks follow-up. The pigs were sacrificed, and histologic and morphometric analyses were conducted. At 6 weeks, minimal luminal stent diameter was significantly narrower in the control group compared to the 50-mW dose group (p < 0.05). These results were confirmed by morphometric analysis. Neointimal area was also significantly decreased in the 50-mW dose group. CONCLUSIONS Intravascular LPRLL contributes to reduction of angiographic in-stent restenosis and neointimal hyperplasia in this animal model. The optimal dose using the LPRLL balloon system seems to be approximately 5 mW delivered during 1 min.