Venous Reflux Examination And Venous Mapping

A detailed US duplex study of the normal and pathologic venous anatomy (reflux) is essential. A clear graphic notation (mapping) of significant vein diameters, anomalous anatomy, superficial venous aneurysms, perforating veins, presence and extent of reflux should always be recorded during the examination (see Figure 23.1).2,5

The ultrasound examination is conducted with the patient standing.9 This position has been found to dilate leg veins maximally and challenges vein valves. Sensitivity and specificity in detecting reflux are increased in examinations performed with the patient standing rather than when the patient is supine.8,9 Supine examinations for reflux are unacceptable.

The veins are scanned by moving the probe vertically up and down along their course. Duplicated segments, sites of tributary confluence, and large perforating veins and their deep venous connections are identified. Their location measured in centimeters from the floor provides a therapeutic guide. Measurements from the medial malleolus are not as precise. Transverse and longitudinal scans combined with continuous scanning are performed in order to provide a clear mapping of the venous system. Patency usually is assessed by compression of the vein with the transducer.8 Reflux is detected by flow augmentation maneuvers such as distal compression and release of the thigh and calf or the Valsalva maneuver for only the saphenofemoral junction.8 Automated rapid inflation/deflation cuffs are cumbersome but may be used for this purpose and offer the advantage of a standardized stimulus.1012 Reflux greater than 500 ms is considered pathologic.9,13

The diameter of the saphenofemoral junction and femoral vein are recorded for use in judgment for radio frequency VNUS closure© and endovenous laser EVLT treatments.1416 Important information also is offered by the diameters of the GSV at mid thigh and distal thigh. Radiofrequency ablation commonly is applied to treat veins from 2-12 mm in diameter.16 The supragenicular, infragenicular, or immediate subgenicular Great Saphenous vein is often the access point for its laser or radiofrequency ablation.16,17 Therefore the depth of the GSV in these regions is additional data to be recorded.

Accessory veins by definition run parallel to the GSV in the thigh (see Figure 23.1).18 It is imperative to map their course accurately and to note their eventual communication with GSV (see Figure 23.1). They are easily confused with the GSV, especially during continuous longitudinal scanning when the saphenous vein appears to leave the saphe-nous compartment.18

The Great Saphenous vein is then scanned in the leg and the thigh so that tributaries to the GSV should be noted (see Figure 23.1).

The diameters of the popliteal vein and the Small Saphenous vein (SSV) are recorded, as well as diameters of the SSV along its course in the leg. Intersaphenous veins should also be identified and the variability in SSV termination carefully recorded.

The venous reflux examination also includes the mapping of exit and reentry perforating veins (PV).19 PV reflux is detected as outward flow duration greater than 350 ms on the release phase of flow augmentation maneuver (distal compression has higher sensitivity in detecting PVs reflux).1 Perforating veins should be accurately located in their different locations in the leg. Their position should be measured as distance (cm) from the floor in the extended limb.1820

ULTRASOUND MONITORING DURING EVLT AND VNUS CLOSURE© OF THE GSV AND SSV

Thermic coagulation is caused by the application of electromagnetic energy to the endothelial surface of targeted veins.16,21,22 It has been suggested that the coagulation process in laser treatment is related to the intravascular vaporization of blood (steam) with intimal denudation and collagen fiber contraction. Vein wall thickening and rapid reorganization of the vessel to form a fibrotic cord follow.21,22 Occlusion usually is visualized within 10 to 20 seconds from the laser or radiofrequency energy application.22 These techniques have been proven to be safe and effective.23 Percutaneous introduction of the laser or RF catheter has made formerly extremely invasive therapy (SFJ ligation and GSV stripping) more acceptable to the patient in terms of post treatment pain, number of cutaneous incisions, and post-procedural disability.15,16

Before the procedure, it is always recommended to rescan the patient for better identification of the venous segment to cannulate. In this preparatory phase some anatomic landmarks have to be clearly recognizable:

1. Femoral vein

2. Saphenofemoral junction

3. Saphenous compartment

4. Great Saphenous vein

5. Small Saphenous junctional anatomy

Introduction of the introducer sheath is performed percuta-neously using the Seldinger Technique. The supragenicular saphenous vein is usually the access point of choice (see Figure 23.2).17 The intraluminal position of the sheath is ascertained by aspiration of nonpulsatile venous blood. The sheathed laser fiber or a 6 or 8 F VNUS catheter is advanced to a point just distal to the entrance of the epigastric vein.17 Position of the laser fiber is confirmed by direct visualization

Venous Reflux Ultrasound
FIGURE 23.2 The Great Saphenous vein is cannulated using the Seld-inger technique. The puncturing needle is echogenic and can be easily visualized. (Adapted from Pichot O, Atlas of Ultrasound Images, Copyright VNUS® Closure)

FIGURE 23.3 The laser catheter is advanced proximally toward the saphenofemoral junction. Position of the laser fiber is confirmed by direct visualization of the red aiming beam through the skin. (Adapted from Navarro L, Min RJ, Bone' C. Endovenous laser: A new minimally invasive method of treatment for varicose veins: Preliminary observations using an 810 nm diode laser dermatologic surgery, Volume 27, 2:117. February 2001)

FIGURE 23.3 The laser catheter is advanced proximally toward the saphenofemoral junction. Position of the laser fiber is confirmed by direct visualization of the red aiming beam through the skin. (Adapted from Navarro L, Min RJ, Bone' C. Endovenous laser: A new minimally invasive method of treatment for varicose veins: Preliminary observations using an 810 nm diode laser dermatologic surgery, Volume 27, 2:117. February 2001)

of the red aiming beam and that of the VNUS catheter by ultrasound (see Figures 23.3 and 23.4).16

The catheter or sheath appear as a hyperechoic line in the GSV lumen.14,15 Its placement must be precisely at the SFJ 1 cm distal to the epigastric vein (see Figure 23.4).16

Administration of the tumescent anesthesia into the saphenous compartment is monitored by ultrasound.17 The vein is seen as "floating" in an echogenic sea of the anesthetic solution (see Figure 23.5). It is always wise to recheck

Iliocaval Junction Anatomy
FIGURE 23.4 Position of the guidewire and radiofrequency catheter is monitored by ultrasound visualization. (Adapted from Pichot O, Atlas of Ultrasound Images, Copyright VNUS® Closure.)
FIGURE 23.5 Administration of the tumescent anesthesia into the Saphenous Compartment is monitored by ultrasound. SFJ: Saphenofemoral Junction; T.A.: Tumescent Anesthesia. (Adapted from Pichot O, Atlas of Ultrasound Images, Copyright VNUS® Closure.)

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    How to mapping gsv and ssv?
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