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Chapter
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5
Noninvasive Examination of the Patient Before Sclerotherapy
A
Figure 5.5 Brodie-Trendelenburg test. A, The proximal portion of the great saphenous vein is obstructed after the veins have emptied with the leg
elevated. B, The distal veins are then observed after the patient stands. C, The veins are further inspected after the tourniquet is released. In this case, filling
of the veins on standing and additional filling after tourniquet removal constitutes a double-positive test.
B
C
Table 5.2 Perthes’ test
Finding Interpretation
Decreased diameter of varicose
veins
No change in diameter of varicose
veins
Deep venous patency Impairment of calf muscle pump
Increased diameter of varicose
veins
94
Primary varicose veins
Secondary varicose veins
Deep venous obstruction
systems. Information regarding the presence of deep venous
valvular insufficiency and thrombosis is important to note in
patient selection. This avoids causing catastrophic complications, such as pulmonary embolism resulting from an undiagnosed and worsened DVT or venous claudication caused by
further impairment of venous return. Indeed, these two complications are serious enough to warrant the use of a much
more sensitive and accurate method; therefore the Perthes’ test
is now of more historical than actual clinical importance.
To test for perforator valvular defects, the physician may
embellish the traditional Perthes’ test by placing a tourniquet
around the calf just below the popliteal fossa.
34
If the dilated
superficial veins in the calf and ankle become less prominent
A
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Nil
A
B
Noninvasive Diagnostic Techniques
Positive
C
Double
positive
D
Negative
Figure 5.6 Interpreting the Brodie-Trendelenburg test. A, Nil: no distension
of the veins for 30 s both while the tourniquet remains on and after it is
removed implies a lack of reflux. B, Positive: distension of the veins only
after the tourniquet is released implies reflux only through the
saphenofemoral junction (SFJ). C, Double positive: distension of the veins
while the tourniquet remains on and further distension after it is removed
implies reflux through perforating veins and the SFJ. D, Negative: distension
of the veins while the tourniquet remains on and no additional distension
once it is removed implies reflux only through perforating veins.
as the patient ambulates, this implies that the blood is being
drawn into the deep system through competent perforating
veins. However, if the veins become increasingly dilated, the
perforating veins must be incompetent. A more involved test,
the Mahorner-Ochsner comparative tourniquet test, similarly
localizes the site(s) of reflux by observing the leg while the
patient walks with the tourniquet placed at various levels on
the leg (upper, middle, and lower thigh) (Fig. 5.9).
32
B
Figure 5.7 A, Compression of fascial defects indicating ‘points of control’
of an incompetent perforating vein with the leg elevated. B, When the
patient stands, the varicose vein remains collapsed while pressure is
maintained over control points and distends when the control point is
released.
Noninvasive Diagnostic Techniques
The preceding three decades have been very fruitful and have
provided a wealth of noninvasive technology that has revolutionized vascular diagnosis. A thorough description of all
these techniques is certainly beyond the scope of this book,
but those not presented here may be found in several excellent
5,13,45
texts.
everyday performance of sclerotherapy, and the following discussion attempts to acquaint the reader with their uses and
limitations.
Doppler ultrasound
Although rapidly being replaced by duplex ultrasound, the
most practical instrument for evaluating patients with venous
disease is Doppler ultrasound. Its first vascular application
Some of the new technologies have real use in the
95
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5
Transmitting
Receiving crystal
crystal
Site of
IPV
Skin
Back scattered sound
A B C
Figure 5.8 Device for the detection of incompetent perforating vein (IPV).
A, Two rubber rings are placed around the ankle, and, B, the more
proximally placed ring is slowly rolled upward. C, As it rolls above an IPV,
the reflux of blood through the IPV causes an immediate distension of a
superficial varix or the formation of a large bulge at the site of the IPV.
Noninvasive Examination of the Patient Before Sclerotherapy
Incident 5–10 MHz sound
Figure 5.10 Doppler ultrasound. Sound waves are emitted from the
transmitting crystal, reflected by moving particles (blood cells) within
the vessel being examined, and picked up by the sensing crystal.
A
Figure 5.11 Bidirectional Doppler tracing. A, Positive deflection indicates
flow toward the probe; B, negative deflection indicates flow away from
the probe.
Blood vessel
B
Figure 5.9 Comparative tourniquet test. Distension of the varices in each
segment of the leg when the patient ambulates implies the presence of
incompetent perforating veins in each segment.
came in 1960 when Satomura and Kaneko46 described a
method of studying changes in blood flow in peripheral arteries using an ultrasonic blood rheograph. Its use in the field of
venous disease was promoted by many groups, including
Sumner et al,
50–54
et al
47
Strandness et al,48 Felix and Sigel,49, Sigel
and Pourcelot et al.55 The instrument is based on the
principle of the Doppler effect and consists of an emitting
crystal and a receiving crystal. Sound waves are directed into
the limb and reflected off the blood cells traveling through the
vessel being examined (Fig. 5.10). The input picked up by the
receiving crystal may be connected to a variety of audio or
graphic recording systems. Dopplers come with either continuous or pulsed-wave ultrasound beams; the continuouswave Doppler is adequate for venous examination, even though
the signal represents a composite of the flow in all vessels in
the path of the ultrasound beam. Thus, selective examination
of one particular vessel may not always be possible. Pulsed
Dopplers are used in sonar systems and in medical ultrasound
96
imaging and are required when the intent is to focus the beam
at a particular depth. Dopplers are also available in either
directional or nondirectional forms. The directional type is
capable of determining the direction of blood flow and depicts
the direction on the tracing as either a positive (toward the
probe) or negative (away from the probe) deflection (Fig.
5.11). Although the directionality greatly simplifies the inter-
pretation of the tracing, experience with a nondirectional
Doppler allows the examiner to make this determination
easily, based on certain augmentation maneuvers.
The transmission frequency of the ultrasound beam may
range from 2 to 10 MHz; the depth of penetration varies
inversely with the frequency. Therefore, a frequency of 4 MHz
produces a broad beam with deep penetration, which is especially useful for examining the deep veins in the pelvis and
abdomen. A frequency of 8 MHz is much better suited for the
examination of more superficial veins, including superficial
segments of the deep veins of the legs, since it produces a
narrower beam with relatively less penetration. Dopplers used
for evaluation of the venous system generally permit detection
of flow rates as low as 6 cm/second.
51
Characteristics of Doppler waveform
Venous Doppler signals display five characteristics (Box 5.2).
In a normal patient, there should be a spontaneous signal over
A
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A
A B C
B
Figure 5.12 A, Method of producing augmentation of flow in the
posterior tibial vein by distal (foot) compression. B, Shows: A, normal flow; B,
venous obstruction; C, valvular insufficiency.
Box 5.2
Venous Doppler characteristics
• Spontaneous
• Unidirectional
• Phasic with respiratory cycle
• Nonpulsatile
• Augmented
any vessel not otherwise vasoconstricted, and the flow should
be only unidirectional. This signal diminishes in intensity
with inspiration as descent of the diaphragm causes a rise in
intra-abdominal pressure, thus decreasing venous outflow
from the leg. It will be augmented similarly with exhalation.
This waxing and waning of the intensity of the signal with the
respiratory cycle is a phenomenon known as phasicity. Venous
signals are continuous except for their respiratory variation
and are not pulsatile, except in the setting of elevated right
heart pressure such as congestive heart failure or tricuspid
insufficiency
important to their usefulness in the evaluation of patients
with varicose veins, venous signals may be augmented with
certain compression maneuvers. It is the response to these
maneuvers that provides information regarding the sites of
valvular insufficiency and obstruction of the venous system.
By compressing the limb distal to the Doppler probe (Fig.
5.12), the examiner increases the flow through the vein; an
immediate increase in the signal intensity should be heard if
there is no proximal obstruction. In the presence of a hemodynamically significant DVT, the augmented response is
weaker and delayed compared with the contralateral side.
With the patient in the upright position, release of distal compression should be followed by silence as the valves close in
response to the downward pressure of the blood being pulled
56
or in the normal CFV.57 Finally, and most
A B C
B
Figure 5.13 A, Method of producing augmentation of flow in the
posterior tibial vein by release of proximal (calf) compression. B, Shows:
A, normal flow; B, venous obstruction; C, valvular insufficiency.
by gravity. With the patient in the supine position, release of
the compression should normally be followed by the return
of the lower intensity spontaneous signal or by silence in the
smaller veins. In the setting of valvular insufficiency at the
level of the Doppler probe, a loud reflux flow signal can be
heard on release of distal compression as blood is pulled in a
caudal direction by gravity. To quantitate this reflux flow, the
compression used may be standardized by using a pneumatic
cuff inflated to a standard pressure (e.g. 80–120 mmHg), and
the amplitude and duration of reflux may be read from
the tracing obtained. To be considered true reflux and not
merely delayed valve closure, the duration of reflux must be
at least 0.5 seconds.
8,58
Although many now believe that over
1 second is the appropriate duration above which to consider
it abnormal.
The other method of augmentation is proximal compression and release (Fig. 5.13). Proximal compression produces a
transient obstruction to outflow and thus causes an accumulation of blood distally, with an associated interruption of the
Doppler signal. On its release, the large bolus of blood flowing
past the Doppler probe creates a loud signal. This has also
been found to be the more sensitive maneuver in diagnosing
DVT, even that limited to calf veins, with a diminished or
delayed signal indicative of a significant thrombosis.
59,60
Valvular insufficiency is discovered easily, because proximal compression yields a loud reflux flow instead of silence.
In early descriptions of the use of Doppler ultrasound for
detection of venous disease, Sigel et al
51
named the various
sounds ‘S’ for spontaneous and ‘A’ for augmented. They further
specified ‘A’ sounds as distal (if the compression was distal to
the probe) or proximal (if the compression was proximal to
the probe), and positive if the ‘A’ sound was heard directly
with compression or negative if heard on release of the compression. This notation thus makes it possible for four ‘A’
sounds to be generated at each site being examined. Table 5.3
summarizes these sounds and their significance. This schema
provides a useful method of categorizing these sounds;
Noninvasive Diagnostic Techniques
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5
A B
InspirationInspiration
Figure 5.14
through the saphenofemoral junction with intermittent compression of
the abdomen or with Valsalva maneuver and release (not shown).
Table 5.3 Interpretation of ‘A’ sounds
Noninvasive Examination of the Patient Before Sclerotherapy
Type of ‘A’
Sound
Distal positive Normal Venous obstruction
Distal negative Valvular insufficiency Normal
Proximal positive Valvular insufficiency Normal
Proximal negative Normal Venous obstruction or
Augmentation of flow in the common femoral vein or
Condition If
Present Condition If Absent
marked valvular
insufficiency
Normal
Figure 5.15 Venous Doppler tracings. A, Normal phasic flow. B, Reflux
with deep inspiration in the setting of valvular insufficiency.
Small saphenous
vein
Valvular
insufficiency
Femoral vein
however, the ‘S’ and ‘A’ nomenclature has not found generalized acceptance. Instead, sounds are referred to as manifesting
flux or reflux, antegrade or retrograde flow, patency or incompetence, etc.
Augmentation of the most proximal portion of the GSV
and of the more proximal deep veins is accomplished either
by compressing the abdomen or by using a variation of the
proximal compression and release, and the Valsalva maneuver
(Fig. 5.14). The rise in intra-abdominal pressure caused by
descent of the diaphragm is accentuated by contraction of the
intercostal muscles. In the normal patient, an abrupt closure
of the valves results in silence. However, more than 38% of
normal persons have a brief period of reflux at the commencement of the Valsalva.
61
Also, with a weak effort by the patient,
a slow retrograde flow may pass through the valve and produce
a Doppler flow signal because sufficient force to cause valve
closure has not been generated. Visualization of the valves
using ultrasound demonstrates that these valves do close eventually, and that they are not actually insufficient.
the continuation of reflux through at least half of the period
of compression, or at least 0.5 seconds (usually 1–4 seconds),
is important in diagnosing pathologic valvular incompe-
8,58
tence.
A less sensitive, but perhaps more specific, response
may be elicited simply with deep breathing. With valvular
insufficiency, instead of hearing the cessation of flow as the
patient takes a deep breath, flow is reversed and a continuous
signal heard, which shows a reverse deflection on a directional
Doppler tracing (Fig. 5.15). The Valsalva maneuver is sometimes hard to explain to patients, and difficult to standardize;
to facilitate, several tricks have been proposed, for example
blowing into a surgical latex glove.
63
When using the Valsalva
maneuver to produce reflux while listening over more distal
98
62
Therefore,
Figure 5.16 Pathways of reflux are typically through the saphenofemoral
junction but may also be through atypical channels, such as through a deep
vein via a perforating vein into a superficial vein (shown). Reflux may also
travel through a superficial vein via a perforating vein into another
superficial vein (not shown).
diagnosis with Doppler ultrasound. In: Findings in angiology and phlebology, vol 35, New
York, 1989, FK Schattauer Verlag.)
(Redrawn from Schultz-Ehrenburg U, Hubner HJ: Reflux
veins, the examiner must realize that the path of the reflux
may be either straight down the superficial vein or through
the deep vein to the perforating vein and into the superficial
vein (Fig. 5.16).
64
Therefore, additional testing is necessary to
further delineate the exact site of abnormality. This is easily
accomplished by manually obstructing the superficial vein; if
reflux is still heard, the retrograde flow is assumed to be
traveling through the deep and perforating systems.
Doppler examination technique
The Doppler examination of the patient is begun with the
deep veins, several of which are easily accessible.
Femoral Vein
With the patient supine and the hips slightly flexed and externally rotated, the physician first locates the pulsatile signal
of the femoral artery in the groin. If desired, the examination
can also be performed with the patient standing, which
may provide a more physiologic evaluation because most
symptoms occur when the patient is upright and reflux is more
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easily elicited. The Doppler probe is then gradually angled
medially until the spontaneous, continuous sound of the
femoral vein, suggestive of a windstorm, is heard. Clear phasicity with respiration should be detected easily. Patency can
be further tested by manually compressing the thigh or calf
and listening for a strongly augmented signal. Valvular competence may be assessed by listening first for the phasic waxing
and waning of the signal that, in severe cases of insufficiency,
shows a decrease in intensity of the signal followed by a
reversal of flow direction as inspiration progresses, rather than
the expected silence. The patient is then asked to perform a
Valsalva maneuver; alternatively, the physician can press on
the abdomen. These latter maneuvers should cause an abrupt
closure of the valve and silence, followed by a more intense
antegrade flow on release if the valves are competent. A loud
reflux flow heard through the Valsalva maneuver is pathognomonic of valvular insufficiency, which may be present in 5%
to 30% of normal patients and, in one study, was found in
100% of patients with bilateral GSV varicosities.
65
The effort
invested in the Valsalva maneuver may be standardized to
ensure the proper force and reproducibility by asking the
patient to blow into a tube connected to a mercury manometer until the mercury column rises to 30 mm.
Differentiation of femoral from saphenous veins. Because
the SFJ is located close to the femoral artery pulsation, valvular
incompetence at the junction can sometimes be mistaken for
CFV insufficiency. Several techniques can be used to aid in
making this important differentiation. The saphenous vein is
much easier to compress than the femoral vein, so manual
compression using the Doppler probe may occlude the saphenous vein and allow the physician to listen selectively to the
femoral vein. A separate occlusive device, such as the physician’s other hand or a tourniquet, may be used to compress
the GSV distal to the Doppler probe and thus prevent reflux
through it. Any reflux still heard is assumed to be through the
femoral vein. Finally, moving or angling the Doppler probe
in a cephalad direction may enable the physician to direct the
ultrasound beam away from the saphenous vein to a more
proximal segment of the femoral vein. Still, there are a small
number of patients in whom differentiation of femoral from
junctional signals may be impossible to determine by use of
only the continuous-wave Doppler; an imaging procedure
such as duplex scanning, which uses a pulsed ultrasound
beam, may be necessary in such cases.
66,67
To achieve uniform testing of venous reflux between institutions, comparable methods of testing by duplex and Doppler
ultrasound scanning are desirable. In one study, the Valsalva
maneuver was compared with rapid cuff deflation performed
in the 15-degree reverse Trendelenburg position and in
patients’ standing. Duplex technology allowed estimation of
duration of retrograde flow and peak velocity. The general
conclusions of the study was that the Valsalva method is best
performed in the reverse Trendelenburg position as opposed
to standing, but the cuff technique is more effective in the
standing position.
68
Popliteal Vein
For the next site of examination, the popliteal vein, the patient
may be in the supine, prone, or standing position. The most
physiologic position is standing, and it is advisable to perform
all presclerotherapy Doppler examinations in this position. It
is important to have the knee slightly flexed, however, since
full extension of the knee joint may cause a functional obstruction of the popliteal vein. Also, if the examination is performed while the patient is standing, the weight should be
borne on the opposite foot (Fig. 5.17). The pulsatile arterial
signal is located, generally, in the popliteal crease just lateral
to the midline; the Doppler probe may be angled medially to
find a softer, although spontaneous, venous signal, or it may
Figure 5.17 The popliteal vein is examined with the knee flexed and the
weight borne on the opposite foot.
be left over the popliteal artery. Augmentation with either calf
compression or thigh compression and release, as described
previously, discloses both obstruction and valvular insufficiency. The Valsalva maneuver discloses reflux only if the more
proximal deep veins (CFV) are also incompetent. As with
reflux heard at the femoral level, reflux at the popliteal level
may actually be caused by reflux through the SPJ. Therefore,
in any patient who appears to have reflux through the popliteal vein, the test should be repeated while firm manual
compression is applied to the SSV. Obliteration of the reflux
in this manner localizes the site of reflux to the SPJ and not
to the popliteal vein itself. Another method consists of slightly
compressing an uninvolved portion of the calf with one finger,
which causes flow through the popliteal vein and not the
64
SSV.
Popliteal vein reflux can be detected in this way with a
sensitivity of 100% and a specificity of 92%, with most false
positives being the result of variations in the anatomy of the
SSV (see Chapter 1).
8,15,69
The presence of popliteal valvular
insufficiency is an important finding because it is associated
with diminished calf muscle pump function and may be the
most important prognostic factor in the development of
venous ulceration.
8,70,71
This relationship is not absolute,
however; one study showed that popliteal incompetence was
found in only 20% of patients with ulceration and 31.2% of
postphlebitic legs.
61
Although the continuous-wave Doppler is adequate for
testing GSV incompetence, all reflux detected in the popliteal
fossa should be checked by duplex examination. The
continuous-wave Doppler examination has a sensitivity of
95% and a specificity of 100% for SFJ examinations, and a
sensitivity of 90% and a specificity of 93% at the SPJ.
72
Posterior Tibial Vein
The final deep vein that should be examined is the posterior
tibial vein, located just posterior to the medial malleolus and
beside the posterior tibial artery, which has an easily locatable
pulsatile signal. This vein is frequently vasoconstricted, except
if the patient is examined in a warm room, in which a spontaneous signal may be noticeable. Augmentation maneuvers
are the same as described for the other deep veins. Again,
Noninvasive Diagnostic Techniques
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Noninvasive Examination of the Patient Before Sclerotherapy
100
although the Doppler is generally not felt to be sufficiently
sensitive in the diagnosis of DVT below the knee, the response
of posterior tibial venous flow to the release of calf compression has been found to allow an 87% accuracy in this
diagnosis.
59,60
Scanning veins below the knees by ultrasound presents
unique difficulties because of the small size of the veins and
their deep position. The addition of color to the Doppler
examination has improved this situation immeasurably, and
the rates for detection of the posterior tibial, anterior tibial,
and peroneal veins has been raised to 98%, 96%, and 96%,
respectively.
73
Superficial Veins
After the deep veins mentioned previously have been examined, attention is turned to the superficial and perforating
systems. The major saphenous trunks and their junctions with
the deep veins should be examined with the patient in the
standing position. Because of the lower flow rate in these
vessels, a spontaneous signal may only rarely be audible. The
presence of a saphena varix, or a visible bulge over the SFJ, is
nearly pathognomonic of valvular incompetence. The junction is easily located with the Doppler approximately two
fingerbreadths in the femoral triangle below the inguinal ligament. Alternatively, the physician may first locate the SSV in
the thigh and then gradually move the Doppler probe superiorly and laterally while repetitively compressing the GSV until
its location is reached. A positive cough or percussion test may
also help to localize the site of the SFJ. The presence of reflux
on release of more distal compression is indicative of SFJ
insufficiency. Again, the magnitude of the compression can be
standardized for serial comparisons by using a pneumatic cuff
inflated to a specific level. Also, the Valsalva maneuver may
be used to elicit reflux, although manual compression of the
SFJ by the inguinal ligament may occur during a forceful Valsalva, and more proximal competent valves may impede the
retrograde flow,
petent valve.
If no reflux is heard over the SFJ, the physician should not
assume that the entire GSV is competent.
in Hunter’s canal may frequently be the first abnormality to
develop, leading to dilation and incompetence beginning just
below the level of the middle thigh (see Chapters 1 and 3).
Reflux frequently originates in branches of the GSV
‘atypical refluxes’ described by Schultz-Ehrenburg and
Hubner
64
GSV that is limited to the calf suggests insufficiency of the
geniculate or lower leg perforators. Therefore, it is important
to test the GSV for reflux in the groin, at the level of the knee,
and in the lower leg and not to assume that it is normal until
all sites fail to demonstrate reflux. In addition, there is a
growing consensus that dilation may occur because of biochemical abnormalities in the muscle of the varicose vein wall.
Thus, valvular insufficiency may not necessarily be a descending process, as was once assumed. This underscores the need
to evaluate the entire length of the GSV in determining which
portions of the vein to treat.
Examination of the SSV and SPJ is best carried out with the
patient standing and the knee slightly flexed, as previously
described. The SSV is felt more easily with the knee flexed and
the popliteal fossa relaxed.
is still not visible, but it is easily palpable as a spongy tubular
structure leading inferiorly from the popliteal crease. By listening over the popliteal vein and tapping the leg very gently 5
to 10 cm below the probe, the examiner selectively compresses and thus listens to the SSV and not the popliteal vein,
which requires a much stronger force. Since the termination
of the SSV is variable, the exact location of the probe cannot
be known for certain; therefore it is difficult to determine if
any reflux heard is originating from the SPJ or is simply within
74
thus creating the false impression of a com-
75–77
The perforator(s)
33,78
79
; the
may be the most common. Incompetence of the
75
14
When enlarged, the SSV generally
a dilated SSV. The Valsalva maneuver or compression of the
thigh aids in this differentiation because it results in reflux
only if the SPJ is incompetent. Distinction between flow
through the SPJ and popliteal vein can also be difficult but is
facilitated by manually compressing the SSV below the probe
while pressing on the calf, as described previously. Abolition
of the reflux is evidence that the source is the SPJ.
15
Another
method is to listen over a more distal segment of the SSV,
along the posterolateral calf, and to compress and release the
SSV at the popliteal crease. Reflux or only augmentation after
release is detected easily.
Perforating Veins
The examination of perforating veins is, at best, only 80%
accurate using the Doppler.
examination – that is, palpation of fascial defects in which the
incompetent perforator meets a dilated superficial vein at the
depth of the superficial fascia – is perhaps even more helpful.
In fact, published studies document that palpation is accurate
only 51%
37
to 69%39 of the time (Fig. 5.18). This technique,
which is discussed more fully in Chapter 9, yields a large
number of false-positive results because a fascial defect may
result merely from dilation of a superficial varicosity or even
from a separate pathologic process, such as a muscle hernia.
In these situations, the Doppler affords increased reliability.
In fact, Doppler examination for IPVs is advised after preliminary clinical localization of suspected sites (by listening for
the characteristic to-and-fro movement of blood over sites of
palpable defects in the fascia). Some authors have advocated
the placement of tourniquets at 10 cm (4 inch) increments
along the course of the lower leg before listening for flux and
reflux at the sites of fascial weakness while the calf or thigh is
repetitively compressed.
one tourniquet just below the level of the fascial defect and
another just above it. While listening with the Doppler over
each marked fascial defect, the physician compresses the foot
(Fig. 5.19). Any audible signal thus represents flow proximally
through the deep system and outward through an IPV. This
provides greater specificity because it interrupts the flow
through the superficial veins, thus allowing selective examination of the perforating veins. Figure 5.20 provides a rational
method of recording the venous Doppler examination
findings.
80–82
Many believe that physical
80–82
A simpler approach is to place
Post-treatment evaluation
Follow-up examinations of injected veins using the Doppler
contribute more precise information regarding the response
to treatment than physical examination does, because a
vein that has been sclerosed loses both spontaneous and
augmented flow signals. However, the Doppler detects flow
through any vessel passing within the sound-wave beam and
thus does not allow the examiner to be certain that the signal
is from a particular vessel. Also, the Doppler does not differentiate thrombus from fibrosis, because both lead to an
absence of a flow signal. These limitations illustrate the advantages of the duplex scanner, another technologic advance that
is revolutionizing the practice of phlebology (Table 5.4).
Duplex ultrasound scanning
Duplex scanners are ultrasound machines that generally use a
7.5–12 MHz imaging probe along with a 3–5 MHz pulsed
Doppler to enable visualization of the superficial venous
system and to determine the direction of blood flow within
the examined veins. Anatomy, flow within the veins, and the
movement of the valves may also be studied (Fig. 5.21).
Current scanners (sometimes termed triplex if displaying realtime color imaging and pulsed Doppler at the same time) use
a computer-generated color system in which antegrade and
retrograde flow may be coded to appear as different colors (red
84–87
83
Noninvasive Diagnostic Techniques
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A
Figure 5.18 Palpation is often deceptive and clinical localization (P) of perforating veins is inaccurate. Duplex evaluation brings back the correct
localization (X).
B
Table 5.4 Comparison of Doppler ultrasound and duplex scanning in
the presclerotherapy evaluation
Doppler Duplex
Portability Portable Portable
Figure 5.19 After making fascial defects palpable with the leg elevated,
the Doppler is used to detect outward flow at each site. Tourniquets are
placed just proximal and distal to each potential incompetent perforating
vein, and the foot is compressed to produce flow upward through the deep
veins.
or blue) with varying intensities (brighter with lower veloci-
Ease of use Requires short period of
training and experience
Information
obtained
Reliability Less reliable because of
DVT, deep venous thrombosis; SSV, small saphenous vein.
Patency, competence of
venous valves
DVT in thigh (?calf) DVT with greater accuracy
blind, nonpulsed sound
beam
Requires longer period of
training
Patency, competence of
venous valves
Velocity of reflux
Anatomy and anomalies
of venous system
Termination of SSV
Thrombosis vs sclerosis
More reliable because of
actual visualization of vein
being examined
ties, paler with higher velocities), thus allowing immediate
integration of this information by the examiner (Figs 5.22–
5.24). Many new features have been introduced to enhance
picture detail and contrast (B flow, Power Doppler, etc.),
which can be helpful in specific cases. Visual ultrasound
images have one of their greatest uses within the field of
venous disease in the diagnosis of DVT and now have all but
replaced venography in centers where the instrumentation is
available (Fig. 5.25).
88–93
Since the 1990s, alterations in the
frequency range of the probes (higher frequencies: 10–
20 MHz) have enabled clear resolution of superficial and deep
veins, thus introducing an entirely new era in the diagnosis of
varicose veins and their treatment by sclerotherapy.
While studies have demonstrated that the examination is
best performed with the patient standing,
94
it is often difficult
to perform this practically. Most examinations are not performed on a tilt table with patients at least 30 degrees in
reverse Trendelenburg position. The cut-off value for reflux in
the veins is greater than 500 ms, except for the femoropopliteal vein, where it is 1 second (Fig. 5.26).
Aid to sclerotherapy
If the Doppler used to act as the ‘ears’ of the phlebologist, the
duplex scanner must be considered both the ears and eyes
as it allows the examiner to ‘see’ much more than is ascertainable otherwise. The duplex scanner allows for determination
of the exact anatomy, including the important SFJs and
SPJs. The anatomy of the SFJ is generally believed to be
similar in all persons; however, there is actually significant
variation. Although not generally accepted as fact, duplication
of the GSV has been reported to be found in up to 27% of
persons
(Fig. 5.27). Because the termination of the SSV is so variable,
the exact location of the SPJ or the termination of the SSV in
the GSV or its tributaries (the superficial or common femoral
veins) or in tributaries of the internal iliac veins
on the duplex scan (Fig. 5.28). In the past, selective venography
was advised to determine the exact site of termination of the
11–13
and is easily demonstrable with this technology
93
can be seen
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Chapter
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5
Noninvasive Examination of the Patient Before Sclerotherapy
Deep veins Right Left
Common femoral Phasicity
Reflux w/ inspiration
Reflux w/ Valsalva
Duration
Popliteal
Posterior tibial
SFJ
GSV distal thigh
GSV calf
Reflux w/ Valsalva
Reflux w/ thigh compression
Reflux w/ calf release
Reflux w/ calf compression
Reflux w/ foot release
Reflux w/ Valsalva
Reflux w/ calf release
Duration
Trendelenberg’s test
Reflux
Diameter
Reflux
Diameter
SSV before the SSV was operated on.
provides this piece of information noninvasively.
tions into the SFJ or SPJ, if performed under ultrasonic guid-
100,101
ance,
confer an added degree of accuracy and potentially
95–97
Duplex ultrasound
98,99
Injec-
safety to this procedure (Fig. 5.29). Injections into IPVs, particularly in areas of ulceration or lipodermatosclerosis, can be
facilitated greatly by performing them under ultrasonic guid-
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ance.
These areas may be particularly difficult to examine
clinically or with a Doppler alone, and injections administered blindly into these areas can be quite risky because of the
proximity of the posterior tibial vein and artery. Finally, the
anatomic basis for proximal recurrences following GSV or SSV
ligation may be found through duplex scanning. Because
recurrent varicose veins occur in 20% to 80% of patients who
have had varicose vein surgery, duplex scanning has allowed
classification of the recurrences so that future studies can be
conducted in a rational and well-planned fashion.
In addition, as McMullin and Appleberg
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104
have found,
duplex measurement of antegrade flow rates through the CFV,
superficial femoral vein, popliteal vein, and GSV may be used
to determine the degree of resistance within the deep veins
and thus the preferential flow up the superficial veins in
patients with chronic venous insufficiency. If it is found that
the flow rate upward through an incompetent GSV is quite
high in a given patient with disease in more than one segment
of his or her venous system, removal or closure of this vein
SPJ
SSV
Tributary 1:
Location
Tributary 1:
Location
Tributary 1:
Location
Tributary 1:
Location
Figure 5.20 Chart for recording venous Doppler examination. GSV, great
saphenous vein; SFJ, saphenofemoral junction; SPJ, saphenopopliteal
junction; SSV, short saphenous vein.
Reflux
Diameter
Reflux
Diameter
Diameter GSV SSV
Diameter GSV SSV
Diameter GSV SSV
Diameter GSV SSV
Figure 5.21 Duplex scanners may provide clear images of anatomic
structures such as the saphenofemoral junction and venous valves (arrow).
A
Figure 5.22 Color scanners display flow: in the normal direction in blue (A), and reflux flow in red (B).
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B
Figure 5.23 Color Doppler image of the confluence of the epigastric and
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great saphenous vein (GSV) showing reflux into the GSV. (Taken with Terason
2000 system.)
Figure 5.24 Color Doppler image of a perforator in the calf. (Taken with
Terason 2000 system.)
Noninvasive Diagnostic Techniques
Figure 5.25 Ultrasound provides clear images of deep venous thrombosis
(arrow). Thrombus may appear as an echogenic mass or simply result in the
vein being noncompressible.
might be contraindicated. The amount of flow generated by
active dorsiflexion of the foot may also provide information
on the efficacy of the musculovenous pump.
Duplex scanning has allowed definition of the saphenous
vein and its relationship to the superficial fascia and the deep
or muscular fascia (Fig. 5.30). Throughout its length, duplex
scanning has shown the GSV to lie on the muscular fascia. It
is covered in its full length by the superficial fascia or membranous fascia, a connective tissue lamina that descends from
the inguinal ligament to the ankle. This lamina is formed by
the interlacing of connective tissue sheets. After the superficial
fascia arches over the GSV, it fuses with the muscular fascia to
create a saphenous compartment. In duplex scanning, this
compartment has been called the ‘Egyptian eye’.
tification is crucial for correct duplex scanning and separating
varicose tributaries of the saphenous vein from the saphenous
vein itself.
Post-treatment evaluation
Another major use of duplex ultrasound with sclerotherapy is
for follow-up of treatment. As mentioned previously, the
Doppler does not allow differentiation between thrombus
and fibrosis, both of which yield abolition of flow through the
105
This iden-
Figure 5.26 Duplex image showing reflux by pulsed-wave Doppler, lasting
more than 3 seconds. (Taken with Terason 2000 system.)
involved vein segment. The duplex scanner can differentiate
these two situations very clearly. Depending on its age, thrombus may appear as a variably echogenic space associated with
soft tissue swelling and inflammation, whereas fibrosis appears
more often as a dense line with no associated inflammatory
reaction (Fig. 5.31). Because patient response to treatment is
so variable, physicians now can more accurately determine if
the treatment rendered has been completely effective, thus
producing fibrosis, or if the vessel is occluded by thrombus,
thereby necessitating additional treatment. Many apparent
treatment failures with early recurrence are likely to be found
to be the result of inadequate treatment and not inadequate
response.
Another important advantage of duplex ultrasound over
the Doppler is its ability to quantitate venous reflux. This
parameter has been found to have some prognostic potential.
The flow in milliliters per second at peak reflux was measured
in 47 limbs of patients who had chronic venous problems. It
was found that dermatitis or ulceration did not develop if the
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