Drug-Eluting
Stents Safe and Effective for Treatment of In-Stent Restenosis
Clinical Benefit Seen at
Nine Months is Maintained at Four Years
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Sirolimus-eluting
stent |
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February
10, 2010 --
From Arezzo, Italy come long-term large registry
data demonstrating the successful use of sirolimus-eluting
stents for the treatment
of re-occluded bare metal stents. In the current issue of the
Journal of the American College of Cardiology, Dr.
Francesco Liistro and his colleagues at the Ospedale San Donato
report that after four years, the clinical benefit seen at
nine months has held steady with a need to reopen the artery
only 11% of the time. |
First Attempts to Treat In-Stent Restenosis
The proper treatment
of in-stent restenosis (ISR) has been a challenge ever since the
beginning of the stent
era in
the 1990's.
Bare
metal stents
improved upon the angioplasty procedure in many situations, but the
problem of restenosis (re-blockage of the artery) while lessened,
still was seen around 20-25% of the time.
Potential fixes for patients coming back to the
cath lab were tried, first with balloon angioplasty, where a balloon
was inserted and inflated
inside
the
blocked stent.
Result were mixed. A more
sophisticated (and expensive) approach was developed using radiation
in a procedure called brachytherapy. It was thought that irradiating
the
tissue
would suppress re-growth inside the stent. Results were also mixed
and the promise of this technology disappeared as the manufacturers
of the equipment discontinued production.
With the development of the drug-eluting stent
(DES), a new kind of stent that emitted a drug to suppress tissue
re-growth, cardiologists began placing a
stent within a stent, and the results were encouraging. But until
now, the data around safety and effectiveness have only reached periods
of a year or less.
Results of the TRUE Registry: Effectiveness
and Safety
The TRUE (Tuscany Registry of Sirolimus
for Unselected In-Stent Restenosis)
registry followed 224 patients who were treated for ISR at two centers in Italy.
The concept was to get a "real world" scenario: the
patients were consecutive, "all-comers", and no exclusion criteria
due to clinical status were imposed. So complex
cases
were included in the registry:
bifurcation lesions, diabetics, etc. Patients were given dual antiplatelet
therapy (aspirin
and clopidogrel or ticlopidine) for at least 6 months following the
procedure.
At one year, the treatment was 95% successful:
only 5 patients out of
100
needed
to
have another
procedure
to
re-open the artery (and all but one had this done in the cath
lab). After four years, only another 6% had re-blockages occur, making
for a total restenosis rate after four years of 11%.
The safety of drug-eluting
stents has been an issue since the initial concerns about late stent
thrombosis
surfaced
back
in 2006. It was thought that something about these devices caused
blood to clot inside the stent more frequently. The percentage
of increase was small, but the results of a stent thrombosis can
be
devastating, causing death or heart attack half of the time. With
the situation of a stent-within-a-stent, the concern was even higher,
one reason why the treatment of ISR with a drug-eluting stent is
an "off label" indication. However, only 7 patients
had a stent thrombosis after four years (5 definite / 2 possible)
for a stent thrombosis rate of 2.8%.
At the end of the four years, one in ten patients
had died, although less than half were from a cardiac-related cause.
80% of the patients remained free from any major adverse cardiac
event.
These results are similar to those from other
ISR studies, albeit none tracked patients for this long. This study
only used sirolimus-eluting stents (e.g. CYPHER). Whether or
not other types of drug-eluting stents would have similar results
cannot be extrapolated from this data.
Reported by Burt Cohen, February 10, 2010
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