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

In-stent restenosis (ISR) is a major problem within stented arteries. Surfa ce treatment of stents with platinum and gold were found to have the maximu m charge with least neointima formation (NF). This study was designed to ev aluate platinum (maximum electrical charge) as a material to make stents to reduce NF. Iridium was added to make an alloy suitable for stent manufactu re, with the potential to make the stent radioactive. We implanted the nove l 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 sacrif ice. The coronaries were perfusion-fixed and stained, and vessel parameters were analyzed by computer-aided histomorphometry. The thrombus formation a nd the inflammatory response was less in the PI stent (0.04 +/- 0.1 vs. 0.2 4 +/- 0.2, P = 0.005; and 1.1 +/- 0.5 vs. 2.4 +/- 0.3, P < 0.001). The NF f rom PI-stented arteries was smaller in sire than the PS controls (1.9 +/- 0 .6 mm(2) vs. 2.4 +/- 0.4 mm(2), P = 0.06). However, PI stents presented wit h 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 for m a gamma radioactive stent. Cathet. Cardiovasc. Intervent. 51:364-368, 200 0. (C) 2000 Wiley-Liss, Inc.