Diagnostic Examination of the Venous System of the Lower Extremity Varicose vein disease is the abnormal functioning of the venous system of the lower extremity due to valvular dysfunction, which includes ectatic veins and varicosities. When considering sclerotherapy treatment, the phlebologist must first evaluate the patient to determine whether the venous segment is simply a case of telangiectatic veins or more serious varicose veins. The examination begins with the patient’s venous history, including duration of condition, prior treatments such a sclerotherapy, ligation, phlebextraction, and endoscopic dissection, any history of deep vein thrombosis or superficial thrombophlebitis, and the severity of symptoms and their affect on the patient, such as with extensive standing, walking or leg elevation. Indications of varicose vein disease include:
Continuous wave Doppler ultrasound emits a continuous beam of ultrasound waves that detect red blood cells moving within the vessel. Sound waves reflect back to the receiving probe at a different frequency. This change in frequency is converted to an audible sound. Frequencies in the 7- to 10-MHz range are optimal for examining superficial vessels whereas lower frequencies (5–7 MHz) are required for examination of deeper vessels. When incompetent valves are present, compression of the muscles proximal to the Doppler probe produces a long sound while blood flows unhindered distally through incompetent valves [4]. When compression is released, flow stops, as does the emitted sound. During compression of incompetent valves distal to the probe, normal proximal flow is heard, but when compression is released, blood flows distally emitting a prolonged sound because incompetent valves cannot prevent retrograde flow [4, 5]. The deep venous system is evaluated for acute or chronic damage to the valvular system and for the presence of deep vein thrombosis. Demonstration of normal, one-way flow at the iliofemoral junction in the groin, the popliteal vein in the popliteal fossae, and the posterior tibial vein in the medial malleolar region should be evaluated in a warm room to reduce venoconstriction and with the patient lying down. Examination of the superficial venous system is usually performed with the patient standing. Examination of the superficial venous system begins with the patient in the standing position, which will enhance ultrasound imaging. The examination is facilitated with the patient standing on a stool (approximately 6 in. off the floor).With the patient bearing weight on the opposite extremity, the limb under study is abducted at the hip with the knee slightly flexed. The common femoral vein in the groin is imaged first and followed proximally to image the external iliac vein. Doppler recordings are taken during the Valsalva maneuver with spontaneous and phasic flow and with manual calf or thigh compression and release. The vein should be imaged in the sagittal plane with the angle of the Doppler probe less than 60°. Reflux is designated by a reverse flow signal for longer than 0.5 s after release of compression. Similar studies and maneuvers are performed on the common femoral vein. The saphenofemoral junction is next identified. The long saphenous vein just distal to this junction is examined during calf or thigh compression and release. During a Valsalva maneuver, a continuous and pronounced reflux signal is a reliable sign of valvular insufficiency.However,mild and brief reflux can be found in 15% of normal individuals. An equivocal result may require a Duplex ultrasound (DUS) examination [4]. Assessments of long saphenous vein competence in the proximal, mid, and distal thigh are then performed. Assessments with calf compression are made. During the thigh exam, any perforating veins penetrating the muscle fascia that communicate with the long saphenous system and femoral vein should be examined. Perforating veins should be assessed for competency. Incompetence of perforator veins exists if there is deep-to-superficial flow for longer than 0.5 s on manual compression above or below the ultrasound transducer [9]. The popliteal vein is examined in three segments: distal to, proximal to, and at the same level of the saphenopopliteal junction. The saphenopopliteal junction, if located, should be assessed. The short saphenous vein is examined for competence in the proximal, mid, and distal calf segments. Examination of the medial and lateral calf veins takes place with the patient sitting with the leg extended horizontally and the foot resting on the examiner’s knee with the calf muscle relaxed.Assessment of the proximal calf segment of the long saphenous vein is examined for competence and patency from the knee to ankle. The posterior arch vein can also be located and assessed in most patients. Calf-perforating veins from the posterior arch complex (gastrocnemius and soleal perforators or posterior tibial perforators) can be identified and examined for competency by compression above and below the transducer [9]. Deep-to-superficial blood flow greater than 0.5 s on calf or foot compression is considered incompetent. Distal segments of the gastrocnemius vein can similarly be assessed. Doppler studies should also be performed on the posterior tibial vein from the proximal calf to the ankle. The peroneal vein is examined from the same transducer position. The anterior tibial vein only needs assessment in suspected cases of deep venous thrombosis. Routine assessment of the lateral calf and soleal veins is unnecessary unless there are obvious lateral calf varices [9]. Duplex venous scanning is the most advanced modality used to investigate venous disease in the sclerotherapy patient. Duplex scanning is important in the clinical decisionmaking process as well as being useful in the serial assessment of disease progression and treatment effectiveness. Duplex sonography combines venous Doppler blood flow analysis with pictorial anatomic information of ultrasonography. This system is commonly used for evaluation of the deep venous system for thrombosis. Most technicians can accurately evaluate the superficial venous system as well, including detection of blood flow and velocity and vessel structure and diameter. The scanning device involves a B-mode imaging ultrasound probe combined with a 3-MHz directional pulsed Doppler ultrasound [9].Visual assessment of blood flow is made possible with color-duplex imaging, which superimposes blood flow information from the pulsed Doppler onto the B-mode ultrasound image. Color duplex stands apart from the standard duplex instrument because color duplex allows for both anatomic structures and flow patterns to be visualized in one image, allowing the vessel to be located and followed more easily than with standard duplex instrumentation [9]. Blood flow is displayed in color while stationary anatomic structures are represented in shades of gray [9]. Areas of phlebology where duplex examination is essential as a diagnostic tool include the diagnosis and evaluation of the extent of deep venous thrombosis. Accuracies of over 90% have been achieved in the femoropopliteal segment and in 80% of the diagnosis of calf vein thrombosis [9]. Another application of duplex examination is in the evaluation of deep and superficial venous insufficiency. This pretreatment evaluation will ensure that all significant areas of reflux are addressed.Duplex scan is the most important diagnostic tool in the management of recurrent varicose veins where primary anatomy is altered by previous surgical procedures.Duplex examination is also utilized to accurately guide sclerosant injections into incompetent perforator and impalpable superficial axial incompetent veins and reduce adverse effects, including intraarterial injections and deep venous thrombosis [7–9]. And finally, duplex examination is used in saphenous vein mapping prior to procedures such as coronary bypass surgery to ensure venous patency, size (diameter greater than 3.0 mm), and length, and to confirm that the long saphenous vein is not serving as collateral circulation in chronic deep venous insufficiency [9] (Tables 8.5, 8.6).
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