Metallic stents

At least 2 weeks for bare metal stent placement. 

For patients undergoing PCI and receiving stents, the recommended dose is 325 once daily for at least 30 days with bare metal stents, for 3 months with a sirolimus-eluting stent, and for 6 months with a paclitaxel-eluting stent, followed by 75 to 162 mg once daily thereafter. 

According to ACC/AHA 2007 guidelines, clopidogrel is indicated for up to 12 months in NSTE ACS patients, with a minimum treatment duration of 1 month after placement of a bare-metal stent and 12 months after placement of a sirolimus- or paclitaxel-coated stent. 

A new trend in the delivery of medicines is to employ a device component. This may be an implantable pump for insulin, a metallic stent coated with a drug, or unit capable of rapidly vaporizing a discrete dose for inhalation. Such products are regulated by the FDA as "combination" products and may be reviewed by multiple Centers within the Agency, which may require additional levels of documentation to support the product design. 

Rapamycin (sirolimus), a macrolide antibiotic, has been used recently in organ transplantation for its potent immunosuppressive actions by inhibiting both cytokine mediated and growth factor mediated proliferation of smooth muscle cells and lymphocytes [55, 56]. In the RAVEL trial of non-acute single vessel lesions, the Sirolimus-eluting stent was compared to bare metal stent (BMS) in a 1 1 fashion [57]. One-year major adverse cardiovascular events and 6 month neointimal proliferation as assessed by late luminal loss (-0.01 0.33 mm in Sirolimus stent versus 0.80 0.53 mm in BMS) were improved. The Sirolimus-eluting stent thus virtually eliminated in-stent restenosis with no evidence of edge effect, dissection, or in-stent thrombosis. 

Fig. 5.6 Sub-group analysis of SIRIUS drug eluting stent versus standard bare metal stenting at 270 days Massachusetts Medical Society)...

In 2006, however, focus shifted to another rare but potentially catastrophic event known as late stent thrombosis, which, in contrast to subacute thrombosis, occurs months to years after stent placement. It usually occurs before endothelialization is complete. For bare metal stents, this takes a few weeks. However, in drug eluting stents, this process of endotheliazation is delayed [68]. This complication... 

Fig. 5.7 TAXUS IV 9 month sub-group analysis of the Paditaxel eluting stent versus comparative bare metal stent ( 2004 Massachusetts Medical Society)...

Serruys PW, Daemen I. Are drug-eluting stents associated with a higher rate of late thrombosis than bare metal stents Late stent thrombosis a nuisance in both bare metal and drug-eluting stents. Circulation 2007 115 1433-1439. 

Stone GW, Ellis SG, Colombo A, Dawkins KD, Grube E, Cutlip DE, Friedman M, Bairn DS, Koglin J. Offsetting impact of thrombosis and restenosis on the occurrence of death and myocardial infarction after paclitaxel-eluting and bare metal stent implantation. Circulation 2007 Jun 5 115(22) 2842-2847. 

Thus, clopidogrel (LD300 mg + 75 mg/day for one month) is the standard of care after bare metallic stent implantation. 

Recent studies have demonstrated evidence for coronary endothelial dysfunction after drug-eluting stenting, logni et al. (77) studied coronary endothelial function in 25 patients six months after stent deployment and found paradoxic exercise-induced vasoconstriction in coronary segments adjacent to sirolimus-eluting stents, but vasodilation in patients with bare-metal stents. Similarly, Hofma et al. (78) noted a pronounced... 

Rodriguez AE, Granada Jp Rodriguez-Alemparte M, et al. OFfAR II Investigators, Oral rapamycin after coronary bare-metal stent implantation to prevent restenosis the Prospective, Randomized Oral Rapamycin in Argentina (ORAR II) Study. J Am Coll Cardiol 2006 47 1522-1529. 

Van Belle E, Tio FO, Chen D, et al. Fhssivation of metallic stents after arterial gene transfer of phVEGF 165 inhibits thrombus formation and intimal thickening. J Am Coll Cardiol 1997 6 1371-1379. 

In recent years, two multicenter experiments were conducted with oral prednisone therapy in patients undergoing coronary bare-metal stent implantation (44,45). 

Abbreviations BMS. bare metal stent LAD. left anterior descending artery LCX, left circumflex coronary artery LM. left main MVD. multiple vessel disease RCA. right coronary artery. 

Abbreviation BMS, bare metal stent, Source From Ref. 49. ... 

Rodriguez A, Fernandez-Pereira C, Rodriguez -Alemparte M, Oral rapamycin after bare metal stent implantation, Letter to Editor. Catheter Cardiovasc Interv 2006 68 333-334. 

Fernandez-Pereira C, Mieres J, Vigo C, et al, Cost effectiveness in patients treated with drug eluting stents vs bare metal stents and oral rapamycin [abstr], Am J Cardiol 2006 96 7(supp I )-33 I. 

Abbreviations CEL, cellulose DXM, dexamethasone EIPA, ethylisopropylamiloride FIB, fibrin MR methylprednisolone NA, not available Neo-R, neointima reduction PC, phosphorylcholine PCL, polycaprolactone PFM-P75, polyfluoroalkoxyphosphazene PLLA(PLA), poly-L-lactic acid POP, polyorganophosphazene PU, polyurethane Q-DL, Quanam drug eluting stent Q-M, Quanam metal stent SNR sodium nitroprusside TIMP, tissue inhibitors of metalloproteinase. 

Lambert T Dev V Rechavia E, Forrester J, Litvak p Eigler N. Localized arterial wall drug delivery from a polymer-coated removable metallic stent kinetics, distribution, and bioactivity offorskolin. Circulation 1994 90 1003-101 I. 

Kuiper KK, Robinson KA, Chronos NA, etal. Phosphorylcholine-coated metallic stents in rabbit iliac and porcine coronary arteries. Scand Cardiovasc J 1998 32(5) 261-268. 

Bonan R, Bhat K, Lefevre T, et al. Coronary artery stenting after angioplasty with self-expanding parallel wire metallic stents. Am Heart J 1991 1214 522-1530. 

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