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Therapy for Stable CAD:Is the Pill as Mighty as the Balloon?

Therapy for Stable CAD:Is the Pill as Mighty as the Balloon?

More than
1.8 million
cardiac
catheterizations
and
at least 600,000 percutaneous
transluminal coronary
angioplasty (PTCA)
procedures are performed
in the United States annually.
1 The use of these diagnostic
and interventional
modalities continues to
grow even as financial constraints
increase. Yet for
many patients with coronary
artery disease (CAD),
medical therapy may be an
appropriate option.

THE EVIDENCE FOR
MEDICAL THERAPY

Studies suggest that
medical treatment is at least
as beneficial as PTCA in patients
with low-risk stable
CAD. The American College
of Cardiology/American
Heart Association
guidelines recommend that
medical therapy be considered
before PTCA in low risk
patients or those with
mild to moderate angina.2
Low-risk patients are those
who have 1 or 2 major coronary
arteries with more
than 50% stenosis, relatively
normal left ventricular function
(ejection fraction, 40%
or higher), and mild to
moderate anginal symptoms.
Although PTCA may
provide faster relief from
anginal symptoms, no published
evidence demonstrates
that it increases survival
or lessens the risk of
acute myocardial infarction
(MI) more than optimal
medical management in
these patients.

Duke Databank study. A 6-year study published
in 1994 examined
data from more than 9000
patients with symptomatic
CAD who were referred for
cardiac catheterization.3
Thirty percent underwent
PTCA, 37% had coronary
artery bypass graft surgery,
and 33% received unspecified
medical therapy.
As expected, the survival
benefit of revascularization
was greater in patients with
more severe disease. However,
no survival benefit
was seen for revascularization
compared with medical
therapy for those with
1-vessel CAD or less severe
2-vessel disease, despite
the fact that medical therapy
was far from optimal by
current standards.

The second Randomized
Intervention Treatment
of Angina (RITA-2)
trial.
In this study, improvement
in anginal symptoms
was demonstrated after either
PTCA or unspecified
medical therapy in 1018 patients
with CAD, but PTCA
was associated with a greater
risk of mortality (P 4

The Atorvastatin Versus
Revascularization
Treatment (AVERT) study.

This trial demonstrated that
aggressive lipid lowering
was associated with a
greater reduction in ischemic
events than PTCA in
select patients with stable
CAD.5The participants
were 341 patients with
asymptomatic or mild to
moderate angina, relatively
normal left ventricular function,
and a low-density
lipoprotein (LDL) cholesterol
level of at least 115
mg/dL, who were initially
referred for PTCA. They
were randomized to PTCA
or atorvastatin, 80 mg/d.
After 18 months of followup,
the atorvastatin group
had 36% fewer ischemic
events than the PTCA
group (P = .048), a difference
that was not considered
statistically significant
after an adjustment for interim
analyses. However, a
significantly longer time to
the first ischemic event was
noted in patients in the atorvastatin
group (P = .03).

Bypass grafting study.
A recent study examined
the comparative survival
benefits of PTCA, left internal
mammary artery by-
pass grafting, and unspecified
medical therapy in 1188
patients who presented with
proximal 1-vessel CAD during
a 9-year period.6 In this
retrospective analysis of
prospectively collected data,
patients were followed for
5.7 years. Interventional
therapy yielded no significant
mortality benefit over
medical therapy, despite the
fact that more patients in
the medical therapy group
had previous congestive
heart failure, previous acute
MI, and long-term anginal
symptoms.

WHAT CONSTITUTES
OPTIMAL MEDICAL
THERAPY?

Aggressive medical
treatment includes strategies
to control modifiable risk
factors.7such as statin therapy
(Box) to reduce LDL cholesterol
levels—the primary
target of lipid-lowering interventions
according to the
National Cholesterol Education
Program (NCEP) guidelines.
8 These guidelines recommend
that all patients
with CAD aim for an LDL
cholesterol level of less than
100 mg/dL. The ongoing
Treating to New Targets
(TNT) trial, which is following
CAD patients who are
taking atorvastatin, 10 mg/d
or 80 mg/d, to achieve an
LDL cholesterol level of
100 mg/dL or 75 mg/dL, respectively,
will demonstrate
whether aggressive LDL
lowering to well below
100 mg/dL will further reduce
cardiovascular risk.9

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