I
ANHEDONIA
investigate
transient ischaemic
attacks
(symptoms of
stroke
lasting for less than
24 hours). Cerebral angiography can be
used to detect an aneurysm in the brain
or to pinpoint the position of a brain
tumour. Coronary angiography, often
combined with cardiac
catheterization
,
can
identify
sites
of narrowing
or
blockage in
coronary artery disease
.
During angiography, some types of
treatment, such as balloon angioplasty
(see
angioplasty, balloon)
and
embol-
ization,
that
sometimes
eliminate
a
previous need for surgery may be car-
ried out. (See also
aortography
.)
angioma
A noncancerous tumour made up of
blood vessels
(see
haemangioma
)
or
lymph vessels (see
lymphangioma
).
angioplasty, balloon
A technique for widening a narrowed
or blocked section of blood vessel by
the introduction of a balloon-tipped
catheter (flexible tube) into the con-
stricted area of the vessel.
The balloon is inflated to widen the
narrowed area, deflated, then removed.
Balloon angioplasty is used to increase
or restore blood flow in a significantly
narrowed artery in
peripheral vascular
disease
and
coronary artery disease.
Coronary balloon angioplasty is usu-
ally successful in the short term, but
narrowing of the affected vessel may
recur, requiring repeat treatment. Angio-
plasty of peripheral vessels is most
successful
in
treating
the
iliac
and
femoral arteries in the legs. Results have
improved further with the introduction
of
stents
(metal
mesh
structures),
which are inserted into an artery fol-
lowing balloon dilation to help keep the
blood vessel open.
angiotensin
The
name
of two
related
proteins
involved in regulating blood pressure.
The first, angiotensin I, is inactive and is
formed when renin, which is produced
by the kidneys, acts on the substance
angiotensinogen. Angiotensin I is then
converted to the second, active, form,
angiotensin II, by angiotensin-convert-
ing enzyme.
Angiotensin II causes narrowing of
the small blood vessels in tissues, result-
ing in increased blood pressure. It also
stimulates release
(from the adrenal
cortex, the outer part of each
adrenal
gland)
of the
hormone
aldosterone,
which also increases blood pressure.
Certain kidney disorders can increase
the production of angiotensin II, re-
sulting
in
hypertension
(high
blood
pressure). Hypertension can be treated
with
ACE inhibitor drugs,
which reduce
the formation of angiotensin II, or with
angiotensin II antagonists.
angiotensin-converting enzyme
A substance that converts angiotensin I
to its active form, angiotensin II. Drugs
that reduce the action of angiotensin-
converting enzyme are known as
ACE
inhibitor drugs
and are used in the treat-
ment
of
hypertension
(high
blood
pressure) and
heart failure
(reduced
pumping efficiency of the heart).
angiotensin-II antagonists
COMMON DRUGS
• Candesartan •Irbesartan •Losartan
• Valsartan
A group of drugs used in the treatment
of
hypertension
(high blood pressure).
Angiotensin-II antagonists have a simi-
lar action to
ACE inhibitor drugs
(in that
they block the action of
angiotensin
II)
but do not cause the persistent dry
cough that is a common side effect of
treatment with ACE inhibitors.
angular stomatitis
See
stomatitis.
anhedonia
Total loss of the feeling of pleasure from
activities that would normally give plea-
sure. Anhedonia is often one of the
common symptoms of
depression.
PROCEDURE FOR BALLOON ANGIOPLASTY
A blockage or narrowing of a blood vessel
may be treated by introducing a balloon
catheter into the area and then inflating
the balloon to stretch the constricted
part. The balloon is then deflated and
the catheter withdrawn. The procedure
is carried out using a local anaesthetic.
Superficial femoral artery
Common femoral artery
Hollowneedle orcatheter
,
Spine
' ' v
V
-
Pelvis
Femur
Deep
femoral artery
How it is done
A hollow needle is inserted
into the femoral artery (left).
A guide wire is pushed
through the needle into the
artery, then along it (using
X-ray imaging) towards the
blood vessel or heart valve to
be treated. Then the steps
shown below are carried out.
Inflated balloon
Sfenos/s
The thin guide wire is
1
manoeuvred through
the arteries (using X-ray
control) until it is just past
the stenosis (narrowing) to
be treated.
A balloon-tipped
2
catheter (top right) is
then threaded over the
guide wire and pushed
along it until it reaches the
narrowed area.
A sausage-shaped
3
balloon atthe end of
the catheter is inflated
and deflated a few times,
to widen the narrowed
part, and then withdrawn.
A
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