the coronary arteries to modestly increase the
flow of blood, which usually is sufficient to ease
symptoms. Commonly prescribed medications
include nitrates such as nitroglycerin and isosor-
bide, beta antagonist (blocker) medications such
as atenolol and propanolol, and calcium channel
antagonist (blocker) medications such as diltiazem
and verapamil. Cardiologists typically recommend
ASPIRIN THERAPYfor people who have angina pec-
toris, to help prevent MYOCARDIAL INFARCTION(blood
clot that blocks the flow of blood, causing heart
tissue to die).
For some people, the most effective treatment
is ANGIOPLASTYto repair, or CORONARY ARTERY BYPASS
GRAFT(CABG) to replace, occluded coronary arter-
ies. However, many people who have angina pec-
toris remain stable with medication therapy.
Cardiologists disagree about the value of CABG for
people whose only symptom of disease is angina
pectoris, because there is growing evidence that
the risks of the surgery (including rapid occlusion
of the grafts) do not counterbalance the benefits.
Two forms of angina are more serious: unstable
angina and variant angina. In unstable angina,
also called acute coronary insufficiency or prein-
farction angina, symptoms are unpredictable and
do not necessarily correlate to increased demands
on the heart such as physical activity may place.
Many cardiologists consider unstable angina a pre-
cursor to heart attack. With unstable angina,
symptoms may occur during sleep or at rest, are
often intense and extended, and progressively
more severe. Sublingual (under the tongue) nitro-
glycerin may provide relief. As the underlying
heart disease progresses, however, symptoms
become more difficult to control. Angioplasty or
CABG is often the most viable treatment options.
In variant angina, also called Prinzmetal’s
angina, spasm of a coronary artery causes symp-
toms that tend to occur without provocation at
certain times of the day. Specific changes in the
ELECTROCARDIOGRAM (ECG) accompany the symp-
toms. Medication (nitroglycerin or calcium chan-
nel blocker) is the most effective treatment for
most people who have variant angina. CABG may
relieve symptoms that do not respond to medica-
tion, though typically occlusion affects only one
coronary artery to cause the symptoms. Generally
the risks of OPEN HEART SURGERY, such that CABG
requires, outweigh the potential benefits to
replace a single coronary artery. TRANSMYOCARDIAL
LASER REVASCULARIZATION(TMLR), a surgical proce-
dure less invasive than CABG that cardiologists
began using in 1998, shows promise for relieving
angina that does not respond to other treatment.
In TMLR, the surgeon uses a laser to pierce the
left ventricle with narrow channels. As the chan-
nels heal they cause new blood vessels to develop
in the myocardium, improving the flow of blood
to the heart muscle.
See also INTRA-AORTIC BALLOON PUMP(IABP) COUN-
TERPULSATION; ISCHEMIC HEART DISEASE; MEDICATIONS
TO TREAT CARDIOVASCULAR DISEASE.angiogram A diagnostic test to visualize BLOOD
vessels. The test is an angiography; the result is an
angiogram. The cardiologist or vascular specialist
injects dye into the relevant blood vessels to assess
the flow of blood through them, observing the
flow via FLUOROSCOPY(moving X-rays). Angiogra-
phy is useful for diagnosing PERIPHERAL VASCULAR
DISEASE (PVD), CORONARY ARTERY DISEASE (CAD),
VENOUS INSUFFICIENCY, and DEEP VEIN THROMBOSIS
(DVT). The cardiologist does angiography of the
HEARTduring CARDIAC CATHETERIZATION. The risks of
angiography include bleeding or INFECTIONat the
injection site and reaction to the dye. With the
precision and availability of noninvasive imaging
technology such as COMPUTED TOMOGRAPHY (CT)
SCANand MAGNETIC RESONANCE IMAGING(MRI), doc-
tors use noncardiac angiography (angiography of
peripheral blood vessels such as in the legs) prima-
rily when the diagnosis or extent of blockage
remains uncertain or before surgery to correct
blockages.
See also ANGIOPLASTY; CORONARY ARTERY BYPASS
GRAFT(CABG).angioplasty A CARDIAC CATHETERIZATIONprocedure
to widen the opening of an ARTERY, generally as
treatment for ANGINA PECTORIS, CORONARY ARTERY DIS-
EASE(CAD), or PERIPHERAL VASCULAR DISEASE(PVD).
Angioplasty is most effective when the occlusion is
between 70 percent and 90 percent and affects only
one or two locations within the arteries. More
extensive occlusion in the coronary arteries may
require CORONARY ARTERY BYPASS GRAFT(CABG)to
instead redirect the blood flow through replace-12 The Cardiovascular System