Download The deep veins

Venography 1
Investigating disorders of veins
In recent years improved CT techniques, and without radiation exposure by
ultrasound and MRA made Contrast phlebography by direct venous injection
is nevertheless still widely used.
The types of contrast phlebography used in clinical practice include:
 Direct contrast phlebography:
I. Phlebography of the lower Iimb.
2. Pelvic phlebography and inferior vena cavography.
3. Hepatic, renal and gonadal vein phlebography.
4. Phlebography of the upper limb and superior vena cava.
5. Portal phlebography.
Indirect phlebography: can he achieved by serial filming following
arteriography. The latter method is the one routinely used for the
demonstration of the cerebral veins following cerebral angiography and
commonly for the demonstration of the renal veins following selective renal
arteriography. It is also used for portal phlebography following selective
celiac arteriography.
The lower limb phlebography
It should be stated at the outset that lower limb venography, particularly for
suspected thrombosis, is being rapidly supplanted by ultrasound techniques
and in many centers the venographic technique is virtually obsolete.
Phlebography of the lower limb is practiced at most medical Centers for the
following purposes:
I. To demonstrate deep venous thrombosis (DVT) in the calf, thigh,
pelvis or inferior vena cava.
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Venography 2
2. To investigate secondary or recurrent varicose veins thought to be
associated with an abnormality of the deep-venous System.
3. To investigate swollen legs where the differential diagnosis
between lymph edema, cellulitis and venous incompetence (or
obstruction) is not clear.
4. To outline venous malformations.
5. In some cases, however, for example in patients with repeated
pulmonary emboli but no obvious source, the investigation may be
undertaken to exclude the lower limb as a source of emboli.
Normal anatomy
The venous drainage of the lower limb can be divided into two separate
systems, the deep veins and the superficial veins. These are connected by the
communicating veins.
The deep veins in the calf follow the same distribution as the main arteries
but are usually double, forming the anterior tibial, posterior tibial and
peroneal veins.
The communicating veins are usually small and paired and connect the
superficial and deep veins. Normally they are extremely narrow, but they
can become quite large when hypertrophied. They are valved so that blood
only flows from the superficial to the deep veins. Under pathological
conditions they can become incompetent, permitting reverse flow from the
deep to the superficial veins.
The popliteal vein is a smooth large vessel lying behind the knee and passing
up into the femoral vein, which follows the course of the femoral artery.
The superficial leg veins drain into the saphenous veins.
 The short saphenous vein passes up the lateral side of the leg to the
knee, where it passes deeply to join the popliteal vein.
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Venography 3
 The long saphenous vein passes up the medial side of the calf and
thigh and then joins the femoral vein below the groin.
The venous system can be regarded as a blood reservoir, and normally
contains some two-thirds of the body's blood, largely in the lower limbs.
Flow to the heart depends on the pressure gradient between the veins and
right atrium, and is assisted by the muscle contractions, particularly in the
calf, acting as a pump. The veins themselves can also actively contract and
help onward flow of blood. In addition, the valves are of great importance in
preventing retrograde flow, and their destruction or damage by thrombosis
has serious hemodynamic consequences leading to venous incompetence.
Technique
Ascending phlebography
A large number of different techniques have been described in the literature.
No standard technique has been generally accepted. The technique has been
modified over the years, and is as follows:
1. A small needle is inserted percutaneously into a vein on the dorsum
of the foot. Occasionally this may prove impossible, and the needle
may have to be inserted by cut-down. If the foot is swollen or
edematous, prior bed rest with the foot elevated is desirable to
reduce the swelling.
2. Once the needle is in position, compression is applied just above
the ankle and also just above the knee by tourniquets or by
inflatable cuffs. The pressure used is just sufficient to occlude the
superficial veins completely without affecting the patency of the
deep veins.
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Venography 4
3. Contrast medium (40-50 ml) is then injected by hand pressure (in
20-30 s). In some cases more may be required to obtain adequate
filling of the femoral and iliac veins, but it should rarely be
necessary to use more than 80-100 ml. Flow is monitored by
observation with an image intensifier, and films obtained at
appropriate moments as the veins are sequentially filled.
4. While some workers conduct the examination with the patient
supine, others insist that the patient should be tilted on the table into
a 30-60° feet-down position. This is mainly to prevent layering of
contrast medium posteriorly, which gives rise to artefactual filling
defects, and to ensure mixing of blood and contrast medium.
5. The foot and leg should be medially rotated to separate the tibia and
fibula and the deep veins of the calf.
6. The weight should not be borne by the foot being injected, so that
the calf muscles remain relaxed and their veins can be filled with
contrast.
Descending phlebography
This is less frequently practiced but is occasionally used, with the patient
supine on a tilting table and the feet against the footrest. The femoral vein is
punctured at the groin. The catheter tip is advanced 5 cm into the artery and
the catheter strapped down to the skin. The patient is then tilted to the erect
or near-erect position, and contrast medium injected. If the patient performs
the Valsalva maneuver, contrast medium will reflux down an incompetent
femoral vein into the popliteal vein. It has been claimed, however, that
contrast will sometimes flow past competent valves, though it is usually
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Venography 5
possible to assess the degree of true incompetence and show the valves
clearly, particularly when they are competent.
Complications
With the older contrast media, a few patients tolerated the procedure badly
and complained of pain and discomfort in the calf with ascending
phlebography. Nausea, vomiting and minor allergic reactions were also
occasionally seen, as with all contrast media.
The new low-osmolality contrast media should be better tolerated and give
rise to little discomfort.
Care should be taken to ensure there is no contrast medium extravasation at
the site of puncture, as this can be quite painful, and with a large volume of
extravasation, an ischemic or edematous foot, can be serious. Skin necrosis
has been recorded to result from this accident.
Phlebitis and postphlebography venous thrombosis can occur where large
volumes of high-concentration contrast are used. This should be guarded
against by flushing out residual contrast agent with saline at the end of the
procedure, and by using the new low osmolality contrast media.
Radiological findings
In the normal patient the deep veins of the calf are outlined by contrast at
ascending
phlebography
with
cuffs
inflated;
three
paired
veins
accompanying the peroneal, posterior and anterior tibial arteries can be
recognized, the last being smaller than the others. There is no filling of the
superficial or communicating veins.
The popliteal vein is single and commences near the knee joint, passing
upwards to become the femoral vein. Views of the calf are usually obtained
in both anteroposterior and lateral projections.
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Venography 6
Valves are usually obvious in the distended veins but can be accentuated by
the patient performing the Valsalva maneuver.
A good-quality ascending phlebogram will also demonstrate the iliac veins
and inferior vena cava.
If the suspected lesion affects only the pelvic veins or inferior vena cava,
direct pelvic phlebography is to be preferred (see below).
Deep venous thrombosis
Venous thrombosis appears to be multifactorial in origin, and is associated
with slowing of the blood flow and an increased liability to blood
coagulation. Conditions known to predispose include malignant disease, age,
obesity, trauma and surgery, as well as prolonged immobilization,
myocardial infarction and congestive heart failure.
Clinically, symptoms are present only if there is significant obstruction or
inflammation produced by the thrombosis, and it is claimed that 50% or
more of cases are silent and symptomless.
Varicose veins
Varicose veins occur in 4% of the adult population and can give rise to
significant morbidity owing to ulceration, hemorrhage, thrombosis and
eczema. Varicose veins are described as being either primary or secondary
in nature.
 Primary varicose veins are always the long and short saphenous veins
and are frequently associated with incompetent perforating veins; the
deep venous system is, however, normal.
 Secondary varicose veins, on the other hand, occur as a result of
previous DVT.
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Venography 7
Varicography may be employed; this involves the direct puncture of a varix
with a 21 G or 23 G needle so that the perforator responsible can be
identified and dealt with.
UPPER LIMB VENOGRAPHY
Anatomy
As in the lower limb, there is a superficial and deep system of veins, both of
which drain into the axillary vein, although in the arm it is the superficial
system that drains most of the blood. Paired deep veins accompany the
ulnar, radial and brachial arteries. Two major superficial veins, the basilic
vein and the cephalic vein, communicate at the antecubital fossa via the
median cubital vein. The cephalic vein ascends on the lateral aspect of the
arm to drain into the axillary vein. The basilic vein ascends medially to join
the deep brachial veins to become the axillary vein. The axillary vein
continues as the subclavian vein. This vessel in turn is joined by the internal
jugular vein to form the brachiocephalic or innominate vein. The right and
left brachiocephalic veins unite to form the superior vena cava.
Technique
The most common indications for upper limb venography are:
Assessment of the central veins when there are symptoms or signs of venous
occlusion (e.g. superior vena caval obstruction).
Dialysis shunts and fistulas: The visualization of arm and central veins
before the fashioning of an arteriovenous fistula for dialysis and the
assessment of poorly functioning dialysis shunts and fistulas.
When studying the central veins, DSA greatly facilitates the examination;
bilateral antecubital fossa veins should be cannulated and simultaneous
injections of approximately 30 ml of contrast medium are made during
image acquisition at two frames per second.
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Venography 8
PELVIC VENOGRAPHY
Techniques
The external and common iliac veins and inferior vena cava can be
demonstrated by means of ascending phlebography from a pedal injection or
by direct puncture at the groin. They can also be catheterized retrogradely
using a catheter inserted from the contralateral groin, jugular vein or arm.
The internal iliac veins and their tributaries can also be selectively,
retrogradely cannulated and opacified.
Dr. ABEER EL SOBKY