Although the symptoms and signs of arterial
occlusive disease may be unmistakable, in many cases
there is difficulty in establishing a definite diagnosis by clinical
examination alone. Measurement of
the ankle/brachial pressure index is a useful guide to the presence of
arterial occlusive disease but
performed only in the resting state may not always reflect the extent
of disease. An exercise study
involves measurement of arterial pressure down the length of the leg
both before and after exercise
on a treadmill. This allows exclusion of patients with spinal
claudication or other causes of leg pain
and in those with arterial claudication gives an indication of the
level of the problem.
A post exercise decrease in ankle pressures suggests an abnormal study
and is followed up with an
arterial duplex scan to determine the nature and level of the disease.
This identifies those cases
that are suitable for minimally invasive endovascular techniques such
as angioplasty as opposed to
those that will require surgical intervention.
Abdominal aortic aneurysm can be screened with
ultrasound making very accurate measurements of
aneurysm sac.
Duplex scanning is able to detect the onset of stenosis within a bypass
graft. This commonly occurs at the anastomotic junction with the native
vessels but occasionally is seen at the site of a valve leaflet in the
body of the graft. Once these abnormalities are identified a minor
surgical procedure or an endovascular procedure may successfully treat
the problem. Serial duplex ultrasound examination of bypass grafts has
been shown to produce a 15% increase in the patency of grafts. As most
problems occur within the first two years of surgery, grafts are
scanned 3 months after the initial operation, then at 6 months, and
then at 6 monthly intervals for a period of 2 years. Following this
yearly scans are performed.
Sample Report of Graft Surveillance Programme.
Thoracic outlet
syndrome
poses a difficult diagnostic dilemma. Symptoms
are usually due to compression of the brachial plexus rather than the
subclavian artery and may be difficult to differentiate from cervical
spondylosis, carpal tunnel syndrome or the vasospastic disorders.
Rarely the compression from a cervical rib is severe enough to result
in aneurysmal dilatation of the artery and subsequent embolic episodes
to the fingers or total occlusion of the artery.
The key to diagnosis is demonstration of obliteration of peripheral
pulses on abduction and external rotation of the arm however up to 50%
of normal men show evidence of positional reduction in flow. This
finding is therefore only significant in association with symptoms of
nerve compression.
Photoplethysmography probes are attached to the fingers and recordings
taken with the arm first at rest and then in a series of 5 different
positions. This is followed up by an arterial duplex scan from the subclavian to the radial and ulnar arteries.
Vasospastic disorders
These include primary and secondary cold sensitivity of the Raynauds
type, livedo reticularis and acrocyanosis. There is reduced arterial
pressure to the extermities as a result of intense vasoconstriction and
this can be documented by measuring a digital/brachial pressure index
using Doppler ultrasound in a similar
manner to the ankle/brachial pressure index in the leg. The test can be
complimented by a cold water immersion test to precipitate symptoms
A typical test report.
Stroke is a devastating event for all
involved and is the third most common cause of death.
The results of several major trials both in the U.S.A. and in Europe
have shown highly significant stroke risk reduction rates after carotid
endarterectomy performed for patients with >70% stenosis of the
internal carotid artery who had suffered recent neurologic symptoms.
The Asymptomatic Carotid Atherosclerosis Study published a report in
May 1995 showing that patients who have had NO symptoms but have
>60% stenosis also have a reduced 5 year risk of stroke if
endarterectomy is performed.
Current research has also revealed that stenosis of the artery is not
the only factor contributing to risk and that the type of plaque
present is highly significant.
Duplex
scanning has proved to be enormously valuable
for the characterisation of plaque. Dense homogenous plaque has been
shown to be seldom associated with stroke whereas soft heterogenous
plaque, particularly where there has been recent intraplaque
haemorrhage, is associated with a high risk of stroke.
Duplex scanning is non-invasive, involves no discomfort and carries no
risk of stroke precipitation. It is therefore the perfect tool for
assessment of the carotid arteries. The patient is examined while lying
on an examination bed with head turned to one side. The common carotid,
internal carotid and external carotid arteries are examined for
patency. Measurement of velocity of blood flow in the vessels gives an
accurate evaluation of the narrowing of the lumen by plaque. The type
of plaque, any intraplaque haemorrhage and surface ulceration are
noted. The accuracy of duplex ultrasound has reduced the
dependancy on Digital Subtraction Angiography pre-operatively thus
reducing risk of stroke
Venous disease is approximately 10 times
more common than arterial disease in Western society.
Deep Vein
Thrombosis
Thrombosis in the lower limb results in symptoms ranging from none to
phlegmasia cerulea dolens. The success of clinical examination in
making a definitive diagnosis of DVT has been shown to be 50%. Since
the complication of pulmonary embolism can be fatal, an objective
assessment is mandatory. Though venography
used to be considered the
"gold standard " in the assessment of the venous system it has now been
superseded by duplex ultrasound scanning.
Venography is invasive, painful and carries a risk of damage to the
veins. Performed by an experienced sonographer, duplex ultrasound is
99% accurate in the diagnosis of thrombus in the major axial veins and
90% accurate in the smaller veins. Duplex scanning also has the advantage of providing a definitive diagnosis
in patients with ruptured Baker's cyst or musculoskeletal injury both
of which can mimic DVT.
Chronic Venous Insufficiency
Normal venous function requires
competent venous valves, patent veins
and an effective calf muscle pump. Failure of any one of these
components results in chronic venous insufficiency. Effective
management of the problem is entirely dependant on an accurate
diagnosis. Incompetence of the superficial veins can be corrected
surgically or with Ultrasond Guided
Sclerotherapy with dramatic clinical and functional improvement.
Incompetence or
occlusion of the deep veins cannot be treated surgically and graduated
compression must be applied to the limb.
The venous duplex
scan is performed with the patient standing
as this most closely simulates normal physiological conditions. The
patency of the veins from the external iliac down to the calf veins is
assessed by means of local compression and augmentation of venous flow.
Competence of the valves is then checked throughout the deep and
superficial veins of the leg. It is not uncommon for segmental reflux
to be present. Perforating veins are then examined and again their
competence checked. A complete map of the venous system is thus created
and the abnormalities noted.
If there is suspicion of proximal occlusion of the major veins an
outflow examination is performed using plethysmography. A positive
result indicating evidence of obstruction in the pelvic veins is
followed by an abdominal scan to examine the Inferior Vena Cava and the
iliac veins. This must be performed in the fasting state to minimise
bowel gas in the scan.
COMPRESSION
THERAPY
Graduated compression of the lower limb is the only treatment that has
been proved to be effective in the healing of venous ulcers.
Bandages are commonly applied ineffectively and do not supply graduated
compression. Even those that are applied well have been shown to lose
their compression within 3 hours.
Class 2 Graduated compression stockings supply a pressure of 30-40mmHg
at the ankle and their use results in the rapid healing of ulcers,
however, they are not universally applicable. Where there is
concomitant arterial disease stockings may exacerbate ischaemia and
even precipitate limb loss. The ankle/brachial pressure index should be
checked and should be greater than 0.8.
Compression stockings are very difficult to get on and are particularly
unsuitable for the elderly patients in whom they are most frequently
required. Arthritis, immobility and general weakness often make it
impossible for the patient to manage them and unless help is available
from family or nursing personnel they are inappropriate.
It is possible to obtain stockings with zippers which are easier to
manage. Unfortunately these are expensive and often cost prohibitive.
A proportion of patients find the graduated compression stockings
intolerable because of pain or heat and refuse to use them.
Intermittant compression therapy is now available in portable home
units. The leg is placed within an inflatable boot and this boot fills
with air starting from the foot and progressing up the leg. The
pressure applied to the limb can be adjusted. The pressure is
maintained for 90 seconds and then released. The cycle is repeated
after 90 seconds rest. The boots can only be used while the patient is
resting and the therapy should be maintained for 3 - 4 hours a day for
effective results. The treatment is time consuming but the results are
often dramatic in appropriate cases. This is a good alternative if
graduated compression stockings are contra-indicated.
SSVC has a supply of graduated compression stockings of various types
which are available to patients at retail price. Measurement and
fitting of stockings is performed by trained personnel.
Intermittant compression pumps are available for use at a nominal rent.
Male sexual dysfunction has many causes and is
frequently psychopathological however it is essential that an organic
cause be excluded.
Organic causes of erectile impotence can be classified as endocrine,
drug induced, local, neurologic and vascular.
Vascular insufficiency results in insufficient blood flow to obtain or
maintain the erect state. The problem may be due to large vessel
occlusion (Leriche syndrome) or to small vessel disease.
Measurement of penile systolic blood pressure using a Doppler
technique allows the penile/brachial index to
be calculated. An index of > 0.75 is normal and an index of < 0.6
is suggestive of vascular insufficiency. An index between 0.6 and 0.75
is indeterminate and requires further investigation.
A duplex
ultrasound scan of the aorta and iliac
arteries allows diagnosis of large vessel occlusion or stenosis which
is correctable either by an endovascular procedure or by open operation.
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