Here is a recent article about that.

Link:

http://www.theheart.org/viewArticle.do?primaryKey=325693

But you have to sign up.

I would ask the Dr. if thinks both asprin and plavix are needed after 1 year.
I do not know what the guidelines are.

Bill - not a Dr.

______________________________

Late stent thrombosis reported with drug-eluting stents

     Oct 21, 2004  Sue Hughes

Rotterdam, the Netherlands and Washington, DC - The reporting of four cases of
late stent thrombosis in patients receiving drug-eluting stents who
discontinued antiplatelet therapy has heightened concerns about this
complication with these stents.1

The four cases, published in a research letter in the October 23, 2004 issue
of the Lancet, are described by a group led by Dr Eugne McFadden
(Thoraxcenter, Erasmus University, Rotterdam, the Netherlands) and Eugenio
Stabile (Washington Hospital Center, Washington, DC). They point out that
concern has arisen about the potential for late stent thromboses with
drug-eluting stents related to delayed endothelialization of the stent struts.
The four cases reported here, each of which resulted in an MI, all developed
between 11 and 15 months after implantation of drug-eluting stents shortly
after antiplatelet therapy was discontinued. In the two patients who had both
a bare-metal and a drug-eluting stent, only the drug-eluting stent showed
evidence of thrombosis. Two cases involved paclitaxel-eluting stents and two
cases involved sirolimus-eluting stents.

"Serious clinical implications"
Senior author of the paper, Prof Patrick Serruys (Erasmus University,
Rotterdam) comments: "We report these cases to draw attention to a problem,
with serious clinical implications, that might be underreported. We suggest
that the potential risk of stent occlusion should be considered when
discontinuation of antiplatelet therapy is contemplated in patients with
drug-eluting stents. As the use of drug-eluting stents becomes widespread,
careful long-term follow-up of patients with such stents is needed to assess
the true rate of late thrombosis."

Think carefully before stopping aspirin even before surgery
Another coauthor of the report, Dr Andrew Ong (Erasmus University, Rotterdam)
told heartwire that these reports emphasized the importance of lifelong
aspirin therapy in patients receiving drug-eluting stents. He explained that
three of the four patients described in the current report stopped aspirin
before undergoing surgery. "What we are saying is that in patients who have
had a drug-eluting stent, the consequences of stopping antiplatelet therapy at
any time must be weighed carefully. In some surgical procedures it may be
possible to continue aspirin. If a patient is undergoing brain surgery where
the consequences of bleeding can be critical, it would obviously be best to
stop aspirin, but if someone is just having a small skin cancer removed, it
may not be necessary to stop antiplatelet therapy. This is for each individual
surgeon to consider."

Ong believes these four cases of late stent thrombosis are the first to be
published with drug-eluting stents. "We have heard of other anecdotal cases
but I believe these are first published reports," he commented to heartwire.
"It is not unexpected for a few cases of late stent thrombosis to occur with
drug-eluting stents, and these reports represent a very low number, but it is
important to realize that it does happen, particularly when antiplatelet
therapy is stopped," he added. Ong explained that patients with drug-eluting
stents may need longer antiplatelet therapy than those with bare-metal stents
as the drug-eluting stents may delay healing in some way.

He added: "Drug-eluting stents are still associated with much better
restenosis rates, and these reports of a few cases of late stent thrombosis
are not going to change anybody's use of these stents. It is recommended that
all coronary artery disease patients receive aspirin for life anyway, and we
are just saying that particular care should be taken in patients with
drug-eluting stents if aspirin is stopped for any reason."

Drug-eluting stents delay vascular healing

In the paper, McFadden et al note that stent thrombosis usually results in
ST-segment-elevation MI or death, but late (later than six months) stent
thrombosis is extremely rare with bare-metal stents except after intracoronary
irradiation, which delays endothelialization of the stent and vascular
healing. There is concern that drug-eluting stents might also be susceptible
to late thrombosis as they also delay endothelialization. Although a recent
meta-analysis of 11 randomized trials (5013 patients) showed no evidence that
the short- to medium-term safety profiles of sirolimus-eluting or
paclitaxel-eluting stents differed from those of bare-metal stents, these
trials were not powered to detect rare events such as stent thrombosis, they
add.

They further point out that dual antiplatelet therapy is prescribed on an
empirical basis for three to six months after implantation of drug-eluting
stents, and then aspirin is recommended for life. "Our report shows that
thrombosis can arise very late after uncomplicated placement of a single
drug-eluting stent, in a large vessel, when antiplatelet therapy is
discontinued," they write. They report that studies with bare-metal stents
suggest that discontinuation of antiplatelet therapy after six weeks of
implantation for noncardiac surgery was relatively safe, adding: "The time
window of the occlusions we encountered far exceeds that reported for
bare-metal stents."

"Extraordinarily late presentation"
In an accompanying commentary, Dr Mark J Eisenberg (McGill University,
Montreal, QC) notes that although stent thrombosis has previously been
reported with drug-eluting stents, the current cases "deserve serious
attention because of their extraordinarily late presentations."2 He points out
that because bare-metal stents become endothelialized within a few weeks of
implantation, dual antiplatelet therapy is required for only two to four
weeks, and late thrombosis (more than 30 days after stent implantation) is
exceedingly rare. Because drug-eluting stents cause delayed
endothelialization, trial protocols have mandated more prolonged antiplatelet
therapy, which might explain why late thrombosis has not been prominent in the
trials with drug-eluting stents.

What can be done to prevent late thrombosis?
Eisenberg suggests that to minimize cases of late thrombosis with drug-eluting
stents, cardiologists should think about the potential clinical consequences
before inserting such a stent. "Will the patient need a subsequent surgical
procedure necessitating the interruption of antiplatelet therapy? If so, a
drug-eluting stent might not be the best choice. Will the patient be compliant
with prolonged antiplatelet therapy? If not, a bare-metal stent might be
preferable," he remarks

He also calls for more information about how to manage patients with a
drug-eluting stent, such as large-scale registries and postmarketing
surveillance studies, the identification of high-risk characteristics that may
predispose to late thrombosis, and most important, the optimum duration for
antiplatelet therapy.

He also notes that strategies need to be developed to deal with the
unanticipated interruption of antiplatelet therapy after implantation of a
drug-eluting stent. "In some cases, it might be advisable to do a surgical
procedure without stopping antiplatelet therapy despite the increased bleeding
risks. In patients for whom this is not possible, it might be better to stop
antiplatelet therapy for less than the five days we currently wait. In cases
of elective surgery, it might be best to delay the procedure until a year or
more after implantation of the drug-eluting stent," he comments.

Continuous antiplatelet therapy "critical"
Eisenberg concludes: "The case reports by McFadden and colleagues strongly and
persuasively suggest that stent thrombosis might occur many months after the
implantation of a drug-eluting stent if prolonged and continuous antiplatelet
therapy is not maintained." He adds: "Drug-eluting stents are so new that many
healthcare professionals are not aware of the critical need for prolonged and
continuous antiplatelet therapy. Therefore, both patients and physicians
should be sensitized to the possibility of late stent thrombosis if
antiplatelet therapy is interrupted."

           Sources

             a.. Late thrombosis in drug-eluting coronary stents after
discontinuation of antiplatelet therapy 2004; 364:1519-1521
             b.. Drug-eluting stents: some bare facts 2004; 364:1466-1467

           Related links

             DES meta-analysis holds few surprises, but larger numbers,
longer follow-up still needed
             [HeartWire > News; Aug 12, 2004]

             Virmani still warns the sun will set for drug-eluting stents:
Nature needs to heal, she says
             [HeartWire > News; May 27, 2004]

             Using long drug-eluting stents to treat multiple lesions may
increase intraprocedural stent thrombosis
             [HeartWire > News; May 19, 2004]

             "Late-late thrombosis" with the Cypher stent: Very rare, but
very real
             [HeartWire > News; Jan 26, 2004]