New Stents Make Big Splash
Doctor's View Archive
Medical Author:
Frederick Hecht, M.D.
Medical Editor:
Barbara K. Hecht,
Ph.D.
Oct. 3, 2003 -- This week has been an auspicious one for medicated stents in
coronary arteries. Two important reports have appeared about these stents. One
report is of a large trial of medicated versus nonmedicated stents. It was
published in The New England Journal of Medicine together with an excellent editorial on the topic. The other report appeared in
the London-based journal The Lancet, and is about the use of medicated stents for
long narrowed areas in small coronary arteries. It, too, was accompanied by a valuable editorial.
A Substance from the Soil of Easter Island
A naturally occurring substance called sirolimus was discovered in a soil
sample from Easter Island. Sirolimus first was thought to have some promise as
an antifungal antibiotic but this idea was
jettisoned when sirolimus was unexpectedly found to have immunosuppressive
activity. After the usual delays inherent in drug research and development, the US Food and Drug Administration
in 1999 approved the use of sirolimus as an immunosuppressant agent.
But evidence had been uncovered earlier in the nineties that sirolimus was
also a potent inhibitor of the growth of smooth muscle cells in blood vessels.
The idea was then "hatched" that sirolimus might be used to inhibit
the restenosis (reclosure) of coronary arteries
Today, after a balloon angioplasty has been done to open
a clogged coronary artery, a mesh tube called a stent is often inserted to keep
the artery open. However, restenosis occurs in up to a third of cases when
smooth muscle cells migrate from the vessel wall into the stent. The muscle cells proliferate there
and narrow the interior diameter of the stent.
Sirolimus Stents Show Considerable Promise
Stents medicated with sirolimus have shown promise in
the prevention of restenosis after balloon dilation of simple coronary lesions.
By "simple" coronary lesions is meant, for example, a short area of narrowing in
one coronary artery. The clinical trial reported yesterday in The
New England Journal compared the sirolimus stent with a standard stent in
patients with complex coronary lesions.
The research was done at 53 centers in the US. In the
trial there were 1,058 patients with "complex" coronary lesions. The coronary
disease in
these patients was considered "complex" because of the frequent
presence of diabetes, the high percentage of patients with longer lesions, and
small vessels.
The sirolimus stent proved to be superior to standard stents in the
prevention of restenosis. The rate of failure of the vessel was reduced from 21%
with a standard stent to 8.6% with a sirolimus stent. The investigators conclude
with typical scientific understatement that: " Coronary stents coated with
sirolimus have considerable promise in the treatment of simple and complex
coronary stenoses."
Sirolimus Stents Good for Long Narrowed Areas
The Lancet report focuses on the use of sirolimus stents
compared with bare-metal stents in long narrowed areas in the coronary arteries.
The research was done in Europe. There were 352 patients in the trial. All had a long narrow
segment in a single coronary artery that need to be treated.
Eight months after the stents were put it, the minimum
diameter was significantly greater within sirolimus stents than in the standard
bare metal stents. The rate of restenosis was significantly reduced with the
sirolimus stents compared with the bare metal stents. And at 9 months, fewer
patients with sirolimus stents had had major adverse cardiac events than did controls.
The researchers conclude with precision that: "Sirolimus-eluting stents
are better than bare-metal stents for treatment of single long atherosclerotic
lesions in a coronary vessel smaller than 3 mm in diameter."
A Note to Our Cardiologist
If one of us needs a stent in a coronary artery tomorrow, please forget the
old bare metal stent and put in a medicated stent instead.
And for more information on these topics, please see the following features in MedicineNet.com:
Articles
Sources: This article is based upon information in the following references:
- JW Moses and Others. Sirolimus-Eluting Stents versus Standard Stents in Patients with Stenosis in a Native Coronary Artery. New Engl J Med 2003; 349: 1315-1323. (Original article)
- AR Marks. Sirolimus for the Prevention of In-Stent Restenosis in a Coronary Artery. New Engl J Med 2003; 349: 1307-1309. (Editorial Perspective)
- J Schofer and Others. Sirolimus-eluting stents for treatment of patients with long atherosclerotic lesions in small coronary arteries: double-blind, randomised controlled trial (E-SIRIUS). Lancet 2003; 362: 1093-99. Published online Sept 30, 2003. (Original article)
- U Sigwart. Drug-delivering coronary artery stents: bare metal threatened by extinction? Lancet 2003; 362: Published online Sept 30, 2003. (Editorial Commentary)
Last Editorial Review: 2/1/2005
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