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| publisher = McGraw-Hill | location = New York | pages = 1413 | chapter = Immunosuppressants, Tolerogens, and Immunostimulants | publisher = McGraw-Hill | location = New York | pages = 1413 | chapter = Immunosuppressants, Tolerogens, and Immunostimulants
}}</ref> A sirolimus-eluting stent is produced by ] (]), and marketed under the name ''Cypher''. A successful trial in 2002 led to approval in Europe, followed by FDA approval in the U.S. in 2003.<ref name="NEJM review" /> }}</ref> A sirolimus-eluting stent is produced by ] (]), and marketed under the name ''Cypher''. A successful trial in 2002 led to approval in Europe, followed by FDA approval in the U.S. in 2003.<ref name="NEJM review" />

A second model uses ], another antiproliferative drug. Derived from the ] tree, paclitaxel binds to and stabilizes ]s. Without the dynamic framework provided by these components of the ], the cell cannot undergo ] and so is arrested at the M stage.<ref name="G&G paclitaxel">{{cite book
| last = Chabner| first = Bruce A. | coauthors = Philip C. Amrein, Brian J. Druker, M. Dror Michaelson, Constantine S. Mitsiades, Paul E. Goss, David P. Ryan, Sumant Ramachandra, Paul G. Richardson, Jeffrey G. Supko, & Wyndham H. Wilson |editor = Laurence L. Brunton, John S. Lazo, & Keith L. Parker
| title = ] | origyear = 1941 | edition = 11th ed. | year = 2006
| publisher = McGraw-Hill | location = New York | pages = 1352–1353 | chapter = Antineoplastic Agents
}}</ref> The paclitaxel-eluting stent produced by ] is called ''Taxus'' and received FDA approval in 2004.<ref name="FDA paclitaxel">{{cite web
| url = http://www.fda.gov/cdrh/mda/docs/p030025.html| title = New Device Approval — P030025 — TAXUS™ Express<sup>2</sup>™ Paclitaxel-Eluting Coronary Stent System
| accessdate = 2006-07-22| date = 2004-09-09| publisher = ]
}}


==History== ==History==

Revision as of 08:59, 22 July 2006

An example of a drug-eluting stent. This is the TAXUS™ Express™ Paclitaxel-Eluting Coronary Stent System, which releases paclitaxel.

In medicine, a drug-eluting stent is a stent (a metal scaffold) placed into diseased coronary arteries that slowly releases a drug blocking cell proliferation; this helps to delay or prevent the artery from being re-occluded by smooth muscle and clot (thrombus). The stent consists of a expandable metal framework, a drug to prevent restenosis, and a carrier to slowly release the drug. It is placed over a balloon on a catheter and guide wire and introduced through a peripheral artery, usually one of the femoral arteries. It is threaded back towards the heart; from the aorta, the appropriate coronary artery is entered. The balloon is inflated, cracking and compressing the plaque and expanding the stent. The balloon and catheter are then withdrawn, leaving the stent in place. The stent releases its drug over the next several months. Patients must take antiplatelet therapy afterwards, usually clopidogrel for six months and aspirin indefinitely. Drug-eluting stents have been shown to be superior for many of the conditions that traditional stents (“bare-metal stents”) have been used, and have become quite popular since their FDA approval in 2003.

Current devices

Currently, two models of drug-eluting stents are used. The first successful type released sirolimus (rapamycin), a powerful immunosuppressive and antiproliferative drug. Sirolimus, produced by the bacterium Streptomyces hygroscopicus, binds to the immunophilin FKBP-12. The resulting complex inhibits the mammalian target of rapamycin (mTOR), which has several effects, including preventing the cell from duplicating its genetic material; it blocks the cell cycle at the G1→S transition. A sirolimus-eluting stent is produced by Cordis Corporation (Johnson & Johnson), and marketed under the name Cypher. A successful trial in 2002 led to approval in Europe, followed by FDA approval in the U.S. in 2003.

A second model uses paclitaxel, another antiproliferative drug. Derived from the yew tree, paclitaxel binds to and stabilizes microtubules. Without the dynamic framework provided by these components of the cytoskeleton, the cell cannot undergo mitosis and so is arrested at the M stage. The paclitaxel-eluting stent produced by Boston Scientific is called Taxus and received FDA approval in 2004.Cite error: A <ref> tag is missing the closing </ref> (see the help page). As equipment and techniques improved, the use of PTCA rapidly increased, and by the mid-1980s, PTCA and CABG were being performed at equivalent rates.. PTCA could only be used on limited scenarios, and the vessels had a high rate (30–40% in six months) of restenosis; additionally, 3% required emergency bypass surgery.. Dotter and Judkins had suggested using intraluminal prosthetic devices to maintain blood flow (in arteries of the leg) in 1964, and in 1986, Puel and Sigwart implanted the first stent in humans. Several trials in the 1990s showed the superiority of stent placement to simple balloon angioplasty, and stent placement became increasingly prevalent, reaching 84% of percutaneous interventions by 1999.

References

  1. Michel, Thomas (2006) . "Treatment of Myocardial Ischemia". In Laurence L. Brunton, John S. Lazo, & Keith L. Parker (ed.). Goodman & Gilman's The Pharmacological Basis of Therapeutics (11th ed. ed.). New York: McGraw-Hill. p. 842. {{cite book}}: |edition= has extra text (help)CS1 maint: multiple names: editors list (link)
  2. ^ Serruys, Patrick W. (2006-02-02). "Coronary-Artery Stents". New England Journal of Medicine. 354 (5): 483–495. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help) (extract)
  3. "New Device Approval — Cypher Sirolimus-eluting Coronary Stent". Food and Drug Administration. Retrieved 2006-07-22.
  4. Krensky, Alan M. (2006) . "Immunosuppressants, Tolerogens, and Immunostimulants". In Laurence L. Brunton, John S. Lazo, & Keith L. Parker (ed.). Goodman & Gilman's The Pharmacological Basis of Therapeutics (11th ed. ed.). New York: McGraw-Hill. p. 1413. {{cite book}}: |edition= has extra text (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)CS1 maint: multiple names: editors list (link)
  5. Chabner, Bruce A. (2006) . "Antineoplastic Agents". In Laurence L. Brunton, John S. Lazo, & Keith L. Parker (ed.). Goodman & Gilman's The Pharmacological Basis of Therapeutics (11th ed. ed.). New York: McGraw-Hill. pp. 1352–1353. {{cite book}}: |edition= has extra text (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)CS1 maint: multiple names: editors list (link)
  6. ^ Baim, Donald S. (2005) . "Percutaneous Coronary Revascularization". In Dennis L. Kasper, Anthony S. Fauci, Dan L. Longo, Eugene Braunwald, Stephen L. Hauser, & J. Larry Jameson (ed.). Harrison's Principles of Internal Medicine (16th ed. ed.). New York: McGraw-Hill. pp. 1459–1462. {{cite book}}: |edition= has extra text (help)CS1 maint: multiple names: editors list (link)
  7. Dotter, Charles T. (1964). "Transluminal Treatment of Arteriosclerotic Obstruction". Circulation. 30: 654–670. Retrieved 2006-07-22. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help) (abstract)

See also