Fig. 41.1
Duplex ultrasound report showing the distribution and extent of reflux. The patient presented with varicose veins in both extremities but she was symptomatic only in the left side. She had burning sensation, itching, and pain on prolonged standing that was relieved with limb elevation. On the right side, reflux was found in the GSV from the upper thigh to the knee and at a medial calf tributary of the GSV. SSV and deep veins were normal. On the left side, there was reflux throughout the extent of GSV, in the anterior accessory saphenous vein, a medial calf tributary, two medial calf perforator veins, SSV throughout its length, and a lateral calf tributary. The deep veins were normal
Anatomic variations in both the superficial and deep veins are common. Careful examination and identification of these variations is necessary before any surgical interventions in order to facilitate the entry point and confirm the full treatment zone during venous ablation therapy. Duplication of the PV and femoral vein is common but rare in the GSV and SSV. Triple systems may be seen (popliteal and femoral) and some veins may be hypoplastic or aplastic (e.g., posterior tibial, GSV, and SSV) [20, 21].
Reflux that is confined to the superficial veins often has a mild to moderate clinical presentation (C1–C3), while involvement of the deep and perforator veins is more often associated with skin damage (C4–C6) [22]. Patients with chronic venous disease exhibit 80% reflux, 17% reflux and obstruction, and only 2% obstruction alone [23].
Patients should be standing or placed in a 30° reverse Trendelenburg position with the limb abducted and externally rotated (not the supine position) [5]. However, a sitting position with the limb externally rotated may be utilized to evaluate VRD in veins from the mid-thigh and below in selected patients, if they are unable to stand or lie in bed. The standing and sitting positions allow optimal filling of the veins and show the distribution and degree of reflux more accurately than venography [17].
Multi-frequency linear array transducers are typically used for the assessment of superficial and deep reflux. For veins located within 1 cm of the skin, high frequency transducers are used with ample gel to facilitate imaging. For veins located >6 cm from the skin, a curvilinear transducers of <5 MHz are preferred. This is necessary for the deep veins in obese patients and for scanning of the abdominal and pelvic veins.
Augmentation of blood flow by distal compression of the limb with sudden release is used to determine valve integrity. It may be applied with several methods: release after a thigh, calf, or foot squeeze, manual compression of vein clusters, pneumatic cuff deflation, active foot dorsiflexion, and relaxation. The Valsalva maneuver is used to examine the veins in the groin area only when the compression/release technique is negative.
The vein behaves as a low pressure, collapsible conduit: with compression its flow is increased in a distal-to-proximal direction and upon release the blood flow reverses instantaneously [5]. Hence, if valves are competent, no retrograde flow is documented. In contrast, if valves are incompetent, blood continues to flow in the opposite direction. In an effort to standardize procedures, many IAC-accredited laboratories are using automated pneumatic cuffs with rapid inflation and subsequent rapid deflation [24]. However, in patients with an increased body mass index (BMI) or significant edema, the compression technique is difficult to apply; thus, dorsiflexion/plantar flexion should be used, while the Valsalva maneuver is used in the groin. It is worth mentioning that pneumatic cuffs are superior to manual compression in diagnosing deep venous reflux, especially in difficult cases [25].
B-mode scanning can be used to evaluate the size of the venous segment and to observe the juxtaposition of the valves. In many instances, an image of reflux, both in gray scale and color, can be obtained at several valve sites during normal phasic breathing. The only criterion used, however, for determining reflux in any given segment is the presence of reverse venous flow demonstrated on the Doppler spectral display during the above maneuvers. Examples with DUS from patients with reflux in superficial and deep veins are shown in Fig. 41.2.
Fig. 41.2
Duplex ultrasound of right GSV showing reflux more than 2 s after augmentation
To date, the only study that has evaluated most of the lower extremity veins (16 vein sites examined on each limb), with the largest sample size (n = 80 healthy limbs and n = 60 CVI limbs), provided the following cutoff values for venous reflux: reverse flow >500 ms for superficial, deep calf, and deep femoral veins; >1000 ms for common femoral, femoral, and popliteal veins; and >350 ms for perforating veins (Fig. 41.3). This study demonstrated that patients should be examined in the erect position to improve the accuracy of the DUS examination in detecting venous reflux [4]. Many other studies have also found that reflux in superficial veins with the patient in the standing position in >500 ms.
Fig. 41.3
(a) Male 40 years old with high-velocity, long-duration reflux >4 s in the great saphenous vein at the mid-calf. (b) Male 40 years old with high-velocity, long-duration reflux >4 s in the proximal popliteal vein
A perforator vein is defined as pathologic when outward flow from deep to superficial veins is ≥0.5 s, vein diameter exceeds 3.5 mm, and the location of the perforator is beneath the healed or active venous ulcer [26–28].
All refluxing veins (or segments) and their reflux duration should be documented. A general agreement for timing and patient position across vascular laboratories will add more standardization to the reflux study [10]. Lurie et al. reported increased repeatability when the same technologist performed duplicate tests, at the same time of day, using the same reflux-provoking maneuver, and with the patient in the same position. The same study reported increased reproducibility by having two different technologists perform the test at the same time of day, using the same reflux-provoking maneuver, and with the patient in the same position. Implementation of a standard protocol would elevate the minimal standard for agreement between repeated tests from the current 70% to at least 80%, and with more rigid standardization, to 90% [10].
Site-Specific Ultrasound Examination
Great Saphenous and Accessory Saphenous Veins
The standard ultrasound examination in the groin should begin by identifying the saphenous-femoral junction (SFJ), which is located medially to the common femoral artery. Adjacent to the SFJ, various tributaries can be visualized, along with the terminal and preterminal valves of the GSV [29, 30]. Reflux is generated by various sources, such as SFJ incompetence or lower extremity and pelvic vein insufficiency. Approximately 10% of women have incompetent ovarian vein valves and around 40% of them experience chronic pelvic signs and symptoms as a direct result of venous congestion (Fig. 41.4) [31, 32]. Imaging should also include the inguinal lymph node area and the full length of the GSV, and associated tributaries should be followed to the ankle. The GSV diameter and distance from the skin should be documented since these are used to guide endovenous treatment options [33].
Fig. 41.4
Reflux in the left ovarian vein in a female patient who had two pregnancies and presented with pelvic pain (left panel). Multiple incompetent ovarian veins are seen in the right panel in a female patient who presented with pelvic pain and dysuria
Small Saphenous Vein and Its Thigh Extension
Examination starts in the popliteal fossa with the patient standing. Transverse views to visualize the veins within the popliteal fossa and longitudinal views to identify the presence of the saphenopopliteal junction (SPJ) are applied. It is important to rule out SPJ incompetence with SSV reflux [33]. The latter may occur during calf muscle contraction or compression (systolic phase) and suggests possible PV and/or femoral vein obstruction; however, reflux is typically more obvious during calf release (diastolic phase) [34]. The SSV may join the PV medially, posteriorly, or laterally; hence, it is advisable to document its location in relation to the PV circumference [35]. A central interconnection element of the local venous circuit is the SSV thigh extension that most often unites GSV near the groin [35]. Documentation of the reflux direction from SFJ to SSV or from SPJ/SSV to GSV should be recorded [36]. The thigh extension of SSV may also join the femoral vein, muscular veins in the thigh, deep femoral vein, and pelvic veins. If reflux is found in the SSV thigh extension, it is followed to the uppermost level.
Perforator Veins
Veins are identified as perforators only if they pierce through the deep fascia. Their locations are recorded as above or below the knee. The above-knee perforators are further divided as upper, middle, and lower thigh. Those in the below-knee segment are divided as upper, middle, and lower thirds of the calf [37]. Both transverse and oblique scanning are used to evaluate these veins because their long axis is visualized in these planes. Reflux or outward flow in perforator veins is observed in combination with the superficial and deep veins. Bidirectional flow may be seen in some perforator veins; however, only the net outward flow (from deep to superficial) is evaluated to determine reflux [26]. The examination starts from the medial malleolus, following the cross-section image of the posterior arch and GSV, upward to the knee region. The anterior arch, the anterior and posteromedial accessory veins, and other thigh tributaries are scanned only if they are varicose [38]. The SSV is imaged from the lateral malleolus until its insertion in the PV. Medial and lateral varicose tributaries of this vein are also scanned. Finally, any area with varicose veins or a vein cluster is scanned to detect perforators.
Deep Veins , Deep Thigh Veins , Popliteal Veins , Deep Crural Veins
The CFV is examined in the longitudinal view for phasic flow with respiration, cessation of flow with deep inspiration, possible reflux with the Valsalva maneuver, and the flow during the compression of the thigh or the calf. Whenever continuous flow is detected in the CFV, the scanning protocol is extended to the inferior vena cava and the iliac vessels in search of a possible obstruction [39]. Presence of retrograde flow distal to the SFJ corresponds to true deep venous reflux.
The PV is examined in its full length, above and below the SPJ, and its anatomic and hemodynamic relationship with the gastrocnemius vein should be clarified. The last portion of the examination of the deep veins of the leg involves the depiction of the deep crural veins, with the patient usually in the standing or sitting position. Posterior tibial and peroneal veins should be examined in all patients with past and/or present DVT, since the latter are the most commonly affected veins of the calf [40]. These veins are imaged from the medial aspect of the calf. If the peroneal veins are not seen from this window, then imaging is performed from the posterolateral aspect of the calf.
Nonsaphenous Veins
Nonsaphenous veins are superficial venous segments that are not part of the GSV or SSV system. Nonsaphenous venous reflux occurs more commonly in females with previous pregnancies [41]. Nonsaphenous segments that are usually involved are the gluteal, posterolateral thigh perforator, vulvar, lower posterior thigh, popliteal fossa tributaries, knee perforator, and sciatic nerve veins. Patients are examined in the erect position, and DUS evaluation is used to identify possible connections with the saphenous and deep veins [42]. The presence of gluteal and/or vulvar varices directs the DUS examination to the pelvic veins [32]. Adjunctive imaging modalities are magnetic resonance venography, computed tomographic venography, or contrast-enhanced venography with selective views of the left renal vein, ovarian, and iliac veins to increase the diagnostic yield and guide therapeutic interventions in cases of pelvic reflux [31, 32].
Venous Duplex Ultrasound and Reflux Therapy
VDU is an integral tool, not only to establish a diagnosis but also to guide treatment and evaluate its immediate and long-term effects. One study indicated that VDU can demonstrate a reduction in GSV reflux caused by compression of the lower leg, which explains one major beneficial effect of compression on the disturbed hemodynamics in venous incompetence [43]. Furthermore, the effect of venous ablation, residual, recurrent of reflux, and development of new disease are easily detected by VDU. VDU can map out the source of reflux in the venous ulcers (CEAP 6), whether it is axial or cross over, and confirm obliteration of this reflux after ablation therapy [11]. It also allows treatment of tributaries with ultrasound-guided foam sclerotherapy in the area of skin damage and in patients with neovascularization.
Limitations of Ultrasound
VDU exhibits inherent technical limitations and is an operator-dependent imaging modality [1, 2]. Examination of the lower extremities can be challenging, especially in regards to small calf veins, which may be difficult to clearly visualize [2]. Detection of partial thrombotic obstruction within the lumen of the vein may be difficult to interpret [44]; however, a complete VDU examination (proximal and distal) has become the standard of care in detecting DVT and venous reflux in recent years [4–7, 18, 24, 45–50]. Several anatomic limitations exist that may influence the examination of different venous segments, such as the presence of bowel gas in the detection of abdominal or pelvic veins. Presence of diffuse or localized edema in patients with heart failure, renal failure, or after surgery, respectively, may cause difficulties in the VDU examination of the venous system of the lower extremities [42]. Also, anatomic variations, such as morbid obesity, inability of the patient to cooperate during the examination, and inability of the operator to perform a full scanning due to wounds and bandages can hinder the VDU. In these instances, other noninvasive and invasive imaging modalities such as catheter-based contrast-enhanced venography, magnetic resonance venography, and computed tomography have been used [5, 21, 42, 44]. In experienced hands, the above limitations are posing a problem in fully evaluating the patients in a small number of cases. Despite the abovementioned limitations, VDU remains a simple, noninvasive but dynamic method with a relatively low cost for the detection of venous pathology.
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
