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New
studies highlight refinements in coronary interventions
News conference: 10:30–11:15 a.m., EST, Sunday, March
17
(ATLANTA)—Clinical studies continue to refine the approach
to percutaneous coronary intervention (PCI), improving its
already excellent results. According to one study being presented
at the American College of Cardiology 51st Annual Scientific
Session in Atlanta, March 17–20, 2002, the patient’s
clinical condition is a key factor in determining which drug
will be most effective in preventing blood clots during PCI.
According to another, a late-breaking clinical trial, cholesterol
lowering drugs called statins may benefit first-time angioplasty
recipients. Whether on-site cardiac surgical back-up is necessary
to safely perform PCI remains controversial, however. One
study showed that, with experienced interventional cardiologists,
a telemedicine link providing consultation with colleagues
at a major medical center provides an effective safety net.
A separate analysis, however, concluded that surgical back-up
is valuable.
Medications
that keep blood clots from forming after the insertion of
a stent in the coronary artery reduce the risk of immediate
complications and improve patients’ long-term outcome.
Which specific medication to select from a group collectively
known as glycoprotein IIb/IIIa (GP IIb/IIIa) inhibitors may
depend on the patient’s clinical
condition at the time of stenting, according to new evidence
from the TARGET study, also known by its full name, the Do
Tirofiban and ReoPro Give Similar Efficacy Trial (Gregg W.
Stone, #0032-6). Researchers found that patients who needed
stenting as a result of an acute coronary syndrome—a
risky condition that encompasses both unstable angina and
heart attack—were significantly less likely to experience
a heart attack within 30 days and six months if they were
initially treated with abciximab rather than tirofiban. The
two GP IIb/IIIa medications produced equivalent outcomes in
patients who had stable angina at the time of stenting. (Original
presentation on March 17, 5:15–5:30 p.m.)
A
randomized study promises to clarify whether statins, a class
of cholesterol-lower drugs that have become a mainstay for
heart-disease prevention and treatment, can benefit patients
who have recently undergone their first angioplasty. Such
patients tend to be in their early stages of heart disease,
yet only a third of them survive or remain free of heart attack
or other major heart problems for more than 10 years.
The
Lescol Intervention Prevention Study (LIPS) compared the three-year
outcomes of more than 1,600 patients who began treatment with
fluvastatin after a recent first angioplasty, the procedure
that uses tiny balloons or the metal scaffolds called stents
to widen heart vessels. Average levels of LDL cholesterol,
one of several kinds of “bad” cholesterol, “were
not markedly elevated” among patients in the trial, said
Dr. Patrick Serruys. The LIPS trial could therefore provide
important insights about statin therapy in a group of patients
who are high-risk but might not qualify as such based on an
important traditional heart-disease risk factor, said Dr.
Serruys, of the Thoraxcenter, Erasmus University Hospital,
Rotterdam, The Netherlands.
Dr.
Serruys will present the results of the international LIPS
trial here on Wednesday, March 20, at 8:48 a.m., at the American
College of Cardiology 51st Annual Scientific Session.
Studies
have shown that the most effective way to treat a heart attack
is to open the blocked coronary artery with balloon angioplasty
or stenting. Whether it is safe to do in a hospital not equipped
for back-up coronary bypass surgery—which may be needed
if something goes awry in the catheterization laboratory—has
been controversial. A study from the Mayo Clinic in Rochester,
Minn., not only provides evidence on the safety of such an
approach but also shows the value of telemedicine in expanding
clinical services (Mandeep Singh, #824-6). The study found
no difference in complication rates among nearly 100 heart
attack patients who underwent PCI at the Mayo Clinic’s
main medical center and a matched group treated at an affiliated,
smaller hospital that did not have cardiac surgical back-up
but did provide a telemedicine link for consultation with
Mayo Clinic cardiologists and surgeons. (Original presentation
on March 18, 3:15–3:30 p.m.)
Analysis
of data from the ACC National Cardiovascular Data Registry
prompted researchers to reach the opposite conclusion: that
surgical standby provides an important safety net when patients
undergo PCI (Michael A. Kutcher, #1125-7). After reviewing
more than 100,000 PCI procedures, a team from Rush-Presbyterian-St.
Luke’s Medical Center in Chicago found that although
emergency bypass surgery is rare, predicting which patients
are likely to need it is difficult. More than half of patients
who underwent emergency surgery had PCI on an elective basis
and a similar number had coronary artery obstructions that
were considered to be uncomplicated. (Original presentation
on March 18 at a 3–4 p.m. poster session.)
Moderator:
Dr. George Vetrovec, Medical College of Virginia, Richmond,
Va.
Drug-coated
stents prove strikingly effective in preventing restenosis
News conference: 11:30 a.m.–12:15 p.m., EST, Sunday,
March 17
(ATLANTA)—New research being presented at the American
College of Cardiology 51st Annual Scientific Session in Atlanta,
March 17–20, 2002, reveals striking success in combating
restenosis through the use of stents coated with medications
to prevent cell overgrowth. More important, extensive follow-up
suggests that the beneficial effects are long-lasting.
Stents,
the tiny metal tubes that prop open once-obstructed coronary
arteries, are among the most effective devices for the treatment
of severe coronary artery disease. Still, they can become
blocked themselves in a process known as restenosis, as the
cells in the artery wall respond to injury by multiplying
rapidly and growing into the stent’s interior passageway.
One
of the most intensely watched areas of cardiology today is
the use of coronary stents that elute, or slowly release,
minute amounts of certain anti-inflammatory and immunity-suppressing
medications. Now, a stent that elutes tacrolimus, a powerful
immunosuppressant and anti-inflammatory agent, has been tested
for safety and effectiveness in preventing tissue regrowth
inside the stent. Such “in-stent restenosis” is
a major limitation of conventional stents, the tiny metal
scaffolds that can widen heart vessels.
If
successful, the tacrolimus-eluting stent could potentially
join the list of similar drug–stent combination devices
that have been recently shown to prevent in-stent restenosis.
Tacrolimus has been long available in larger doses as Prograf
(Fujisawa, Japan), which is used for fighting organ transplant
rejection.
The
PRESENT (PREliminary Safety Evaluation of Nanoporous Tacrolimus
eluting stents) trial tested a tacrolimus-eluting stent designed
for coronary arteries, the major vessels that provide blood
to heart tissue. The sister study EVIDENT (Endo-Vascular Investigation
Determining the Safety of a New Tacrolimus Eluting Stent Graft)
evaluated a tacrolimus-eluting “stent-graft” designed
for diseased saphenous vein bypass grafts, the borrowed leg
vein that is surgically attached to a coronary artery to reroute
blood around severe narrowings.
Prof.
Eberhard Grube, of the Heart Centre Siegburg in Germany, is
scheduled to present results from the PRESENT and EVIDENT
studies here on Sunday, March 17, at 9:22 a.m. during the
Late-Breaking Clinical Trials in Interventional Cardiology
Session (#22).
Researchers
have hoped that coating stents with the blood-thinner heparin
would improve these metal scaffolds as a treatment for some
patients with narrowed heart vessels. But a multicenter trial
has shown that such coated stents are no better than conventional
ones at keeping open previously widened but renarrowed small
heart vessels.
In
the Heparin-Coated Stents in Small Coronary Arteries (COAST)
trial, angioplasty balloons or stents with or without heparin
coatings were used in 600 patients with recurrent small-vessel
narrowings. Such patients are particularly challenging to
treat. This is partly because small heart vessels may be more
prone than larger ones to restenosis, a renarrowing process
that is the major limitation of angioplasty—the widening
of heart vessels using tiny balloons or scaffolding stents.
Also, the risk of restenosis is especially high after second
or third angioplasties.
After
six months, none of the three treatment strategies proved
better than another at keeping the small vessels open or preventing
heart attacks or other cardiac problems, according to Dr.
Michael Haude, of University Essen in Essen, Germany.
Dr.
Haude is scheduled to present the COAST trial results here
on Sunday, March 17, at 9:46 a.m. during the Late-Breaking
Clinical Trials in Interventional Cardiology Session (#22).
Sirolimus-coated
stents demonstrate impressive results on long-term follow-up,
according to researchers from Thoraxcenter in Rotterdam, The
Netherlands (Jean Fajadet, #0032-1). More than 200 patients
with a single, new coronary artery obstruction participated
in the RAVEL study, more formally known as the Randomized
Study with the Sirolimus-Eluting Bx VELOCITY Balloon-Expandable
Stent in the Treatment of Patients with De Novo Native Coronary
Lesions. Half received a stent that not only propped open
the coronary artery but also slowly released sirolimus, a
potent drug that suppresses inflammation and prevents cells
in the artery wall from multiplying. Seven months later, this
group of patients showed no signs of cell overgrowth or restenosis,
and no patient required a repeat procedure to open the artery.
By comparison, about one in four patients treated with uncoated
stents experienced restenosis and required a repeat procedure.
Complication-free survival rates were also significantly better
among patients treated with the coated stent. (Original presentation
on March 17, 4–4:15 p.m.)
A
team from Institute Dante Pazzanese of Cardiology in Sao Paulo,
Brazil, reported excellent success over a long period using
the sirolimus-eluting stent (Jose Eduardo Sousa, #0032-3).
Observing for two years the first 30 patients treated as part
of pilot testing of the device, investigators noted no cell
overgrowth in the arterial wall, no restenosis in the treated
portion of the artery, and no need for a second procedure
to reopen an obstructed coronary artery. (Original presentation
on March 17, 4:30–4:45 p.m.)
The
sirolimus-eluting stent demonstrated promising results under
more challenging circumstances as well—the treatment
of patients with restenosis in a previously implanted stent
(Patrick W. Serruys, #823-1). A small multicenter study showed
that, at four-month follow-up, there was no evidence of repeat
restenosis seen on angiography, an x-ray procedure in which
dye is injected into the coronary artery to visualize its
contours; very little overgrowth of the arterial wall seen
on ultrasound images taken from inside the coronary artery;
and a very low rate of major cardiac complications. (Original
presentation on March 18, 2–2:15 p.m.)
A
stent that slowly releases the anti-cancer drug paclitaxel
was evaluated for the treatment of restenosis occurring in
a previously implanted stent (Eberhard Grube, #1174-15). At
the ACC meeting, Investigators from Herzzentrum Siegburg in
Germany and Thoraxcenter in Rotterdam, The Netherlands, will
report on the results of angiography and intravascular ultrasound
six months after stent implantation. (Original presentation
on March 19 at a noon–1 p.m. poster session.)
The
use of oral sirolimus for the prevention of restenosis was
the subject of a study from Scripps Clinic in La Jolla, Calif.,
and Lenox Hill Hospital in New York City (Paul S. Teirstein,
#823-3). Prompted by the limited availability of drug-eluting
stents in the United States, where such devices are classified
as investigational, the study tracked both the safety and
effectiveness of oral sirolimus in high-risk patients with
no other options for combating in-stent restenosis. The oral
version of the medication is approved for the prevention of
organ rejection following renal transplantation. Investigators
will report the results of six months’ follow-up. (Original
presentation on March 18, 2:30–2:45 p.m.)
Moderator:
Dr. Spencer B. King, III, Cardiology of Georgia, Atlanta.
The American College of Cardiology, a 28,000-member nonprofit
professional medical society and teaching institution, is
dedicated to fostering optimal cardiovascular care and disease
prevention through professional education, promotion of research,
leadership in development of standards and guidelines, and
the formulation of health care policy.
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