What They`re Saying About…Drug-Eluting/Coated Stents

A sampling of recent conclusions from researchers around the world. Chondroitin sulfate and gelatin (CSG) coating appears to be a promising medium for localized drug delivery. Paclitaxel polymer-coated stents reduce neointima formation but are associated with evidence of incomplete healing at 28 days. However, neointimal suppression was not maintained at 90 days. For the full story, see: Farb A, Heller PF, Shroff S, et al. Pathological analysis of local delivery of paclitaxel via a polymer-coated stent. Circulation 2001 Jul 24;104(4):473“479. Within 3 weeks of implantation, drug permeation and gene expression in the vascular tissues were observed, indicating that the gelatinous photogel effectively serves as a matrix or coating for a bioactive stent,which permits drug release as well as gene transfer. This intraluminal approach has the potential to realize drug and gene therapy in atherosclerotic plaque. For the full story, see: Nakayama Y, Ji-Youn K, Nishi S, et al. Development of high-performance stent: Gelatinous photogel-coated stent that permits drug delivery and gene transfer. J Biomed Mater Res 2001 Dec 15;57(4):559-566. Corline heparin coating of the Jostent((R))has no impact on the in-hospital complication rate, stent thrombosis or restenosis. The Jostent((R))design gives a high procedural success rate and satisfying result at 6 months in an everyday patient population undergoing provisional stenting. For the full story, see: Wohrle J, Al-Khayer E, Grotzinger U, et al. Comparison of the heparin coated vs the uncoated Jostent((R)) no influence on restenosis or clinical outcome. Eur Heart J 2001 Oct;22(19):1808-1816. Stent-based delivery of (sirolimus) SRL via a nonerodable polymer matrix is feasible and effectively reduces in-stent neointimal hyperplasia by inhibiting cellular proliferation. For the full story, see: Suzuki T, Kopia G, Hayashi S, et al. Stent-based delivery of sirolimus reduces neointimal formation in a porcine coronary model. Circulation 2001 Sep 4;104(10):1188-1193. Local delivery of paclitaxel with the double-balloon-perfusion catheter did not reduce neointima formation following stent implantation in native pig coronary arteries. For the full story, see: Oberhoff M, Herdeg C, Al Ghobainy R, et al. Local delivery of paclitaxel using the double-balloon perfusion catheter before stenting in the porcine coronary artery. Catheter Cardiovasc Interv 2001 Aug;53(4):562-568. [W]e impregnated paclitaxel (175-200 &mgr;g/stent with programmed elution over 6 months) on Gianturco-Roubin(R) II (GR(R)II) stents. ¦ This study shows that the paclitaxel-coated stents significantly reduced in-stent restenosis without eliciting inflammation. For the full story, see: Hong MK, Kornowski R, Bramwell O, et al. Paclitaxel-coated Gianturco-Roubin(R) II (GR(R)II) stents reduce neointimal hyperplasia in a porcine coronary in-stent restenosis model. Coron Artery Dis 2001 Sep;12(6):513-515. Fifteen patients were treated with 18 mm sirolimus eluting BX VELOCITYtrade mark stents. ¦ Implantation of a sirolimus-eluting stent seems to effectively prevent intimal hyperplasia. For the full story, see: Rensing BJ, Vos J, Smits PC, et al. Coronary restenosis elimination with a sirolimus eluting stent; First European human experience with 6-month angiographic and intravascular ultrasonic follow-up. Eur Heart J 2001 Nov;22(22):2125-2130. Coating stents with [fibrin sealant] is not detrimental. IP [Intimal proliferation] in these EA [thirty-40 kg pigs] at 30 days did not produce stenosis. Postoperative [low-molecular weight heparin] appears helpful in maintaining patency in a thrombogenic experimental animal. Further study maintaining EA for 6-12 months should resolve whether the IP seen had achieved its maximum expression or would progress and produce stenosis. For full story, see: Byer A, Peters S, Settepani F, et al. Fibrin sealant coated stents compared with non-coated stents in a porcine carotid artery model. Preliminary study report. J Cardiovasc Surg (Torino) 2001 Aug;42(4):543-549. Thirty-two patients presenting with varied coronary syndromes and anatomy were treated with a new coronary multisleeve drug delivery coronary stent (QuaDS-QP-2) containing up to 4,000 microg of a taxol-derived lipophilic microtubule inhibitor (QP2).¦Although all 13 QuaDS-QP-2 (QDES) stents were angiographically and IVUS patent, two reinterventions have been required in the 32-patient study group thus far, both relate to either new disease or to distal, small-vessel disease beyond the stent. There was no evidence of significant proliferation in the QDES devices. For the full story, see: de la Fuente LM, Miano J, Mrad J, et al. Initial results of the Quanam drug eluting stent (QuaDS-QP-2) Registry (BARDDS) in human subjects. Catheter Cardiovasc Interv 2001 Aug;53(4):480-488. Stent-based delivery of (sirolimus) SRL via a nonerodable polymer matrix is feasible and effectively reduces in-stent neointimal hyperplasia by inhibiting cellular proliferation. For the full story, see: Suzuki T, Kopia G, Hayashi S, et al. Stent-based delivery of sirolimus reduces neointimal formation in a porcine coronary model. Circulation 2001 Sep 4;104(10):1188-1193. In small coronary arteries, both PTCA and elective stenting are associated with good clinical and angiographic outcomes after six months. Compared with PTCA, elective treatment with the heparin-coated beStent improves the clinical outcome; however, there was only a nonsignificant trend toward angiographic improvement. For the full story, see: Moer R, Myreng Y, Molstad P, et al. Stenting in small coronary arteries (SISCA) trial. A randomized comparison between balloon angioplasty and the heparin-coated beStent. J Am Coll Cardiol 2001 Nov 15;38(6):1598-1603. [Titanium-nitride-oxide] TiNOX coating significantly reduces neointimal hyperplasia in stainless steel stents. The antiproliferative effect was similar for both TiNOX coatings, suggesting that the electrochemical properties are more important for attenuation of neointimal proliferation than the observed differences in platelet adhesion and fibrinogen binding. For the full story, see: Windecker S, Mayer I, De Pasquale G, et al. Stent coating with titanium-nitride-oxide for reduction of neointimal hyperplasia. Circulation 2001 Aug 21;104(8):928-933. Because local concentrations and gradients are inextricably linked to biological effect, our results provide a potential explanation for the variable success of stent-based delivery. We conclude that mere proximity of delivery devices to tissues does not ensure adequate targeting, because physiological transport forces cause local concentrations to deviate significantly from mean concentrations. For the full story, see: Hwang CW, Wu D, Edelman ER. Physiological transport forces govern drug distribution for stent-based delivery. Circulation 2001 Jul 31;104(5):600-605.

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