Best Practice. Duplex ultrasound scanning is more accurate than DUPLEX ULTRASOUND SCANNING FOR CHRONIC VENOUS DISEASE OF THE LOWER LIMBS ABSTRACT

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1 pp63-68 Best Practice A R T I C L E DUPLEX ULTRASOUND SCANNING FOR CHRONIC VENOUS DISEASE OF THE LOWER LIMBS K A MYERS AND S R WOOD Richmond Vascular Diagnostics at Epworth Hospital, Melbourne, Australia. Duplex ultrasound scanning is more accurate than clinical examination 1,2 continuous-wave Doppler 2,3 photoplethysmography 4 or descending venography 5,6 provided that it is performed by an experienced vascular ultrasonographer. When duplex scanning is compared to venography, there is >90% agreement for saphenous and major deep venous reflux 7,8 though only 40-60% detection of outward flow in perforators 8. However, correlation with findings at operation shows that duplex scanning is specific for detecting perforators 9 and is considerably better than clinical evaluation or continuous-wave Doppler 10. Discussion is supplemented by our experience, which has previously been reported 11 with findings recorded on a database now for more than 4500 lower limbs with CVD. Results for different diagnostic services will vary according to their referral patterns. TECHNIQUES FOR DUPLEX SCANNING The limb is scanned with the patient standing with weight taken on the opposite limb. The protocol is to examine for incompetence at each saphenous junction and reflux or obstruction in both saphenous veins and their major tributaries. Reflux into or away from the junction through pelvic or abdominal veins in the long saphenous territory, or through the Giacomini or gastrocnemius veins in the short saphenous territory is noted. Diameters at the junctions and in representative sections of the major superficial veins are recorded, for these may determine the choice between echosclerotherapy and surgery. It is futile and time wasting to follow reflux into all of the varicose tributaries for these are already obvious to the treating clinician. The full length of the deep axial venous system from the ankle to the groin is then scanned, noting whether there is normal valvular competence, reflux, or recent or past occlusion. If there is long or short saphenous reflux, then it ABSTRACT Duplex scanning has replaced other investigations for routine assessment of chronic venous disease (CVD). It has greatly added to our knowledge about connections between deep and superficial veins that lead to superficial venous insufficiency (SVI) and has expanded our understanding of deep venous insufficiency (DVI). Air plethysmography (APG) is occasionally required for physiological assessment in patients with complications, and ascending or descending venography or varicography may be needed to clarify anatomy. However, duplex scanning is the primary investigation performed for many patients with uncomplicated primary varicose veins and probably should be mandatory for those with recurrent varicose veins or with complications that may require intervention. is inevitable that their will be reflux in the common femoral vein to the saphenofemoral junction or in the popliteal vein to the saphenopopliteal junction, and this is not described as deep reflux. Richardson and colleagues described techniques to show the inferior vena cava, iliac and ovarian veins 12 and this is greatly assisted by using a tilt-table. We selectively study these in any limb that shows reflux from low pelvic veins across the groin into the long saphenous territory. With experience, all crural veins can be readily identified 13. However, we found that reflux in posterior tibial veins better reflects clinical features and changes at other sites than reflux in anterior tibial and peroneal veins 14 so that it is reasonable not to examine the latter. The importance of the profunda femoris vein has not been adequately studied 15. Reflux can be induced by pneumatic calf cuff deflation, pneumatic thigh cuff inflation, a thigh squeeze, release after a calf squeeze, tipping a tilt-table or by the Valsalva manoeuvre 16. Although the pneumatic calf cuff technique provides a standard outflow 16, manual calf compression is Address correspondence and reprint requests to: Professor Kenneth A Myers, Richmond Vascular Diagnostics at Epworth Hospital, Melbourne, Australia. A USTRALIAN & NEW Z EALAND J OURNAL OF P HLEBOLOGY V OLUME 3(2):November

2 K A Myers and S R Wood probably as reproducible 17 and far simpler. A tourniquet test to selectively occlude superficial veins to distinguish superficial from deep reflux can be used but it is unreliable since it requires widely varying pressures to occlude the superficial veins alone 18. The 95% confidence limits for valve closure time in normal limbs is <0.5sec 19 but we now consider that this time should be extended to >1sec to define deep reflux. Beckwith and colleagues 20 have developed a ratio from the Doppler augmented wave to the reflux wave to measure reflux in deep veins, and this correlates well with measured flow. Calf perforators are readily seen passing through the deep fascia which is a distinct band on the B-scan (Figure 1). The deep source may be difficult to define but the superficial destination is usually clear. Thigh perforators are similarly demonstrated. Outward flow in perforators is then noted by colour-doppler imaging after a proximal muscle squeeze and isometric calf muscle contraction. Their diameters, orientation on the medial, lateral or posterior aspect and distance from a bony landmark such as the pubic tubercle for thigh perforators or malleoli for calf perforators are recorded. Repeating the scan after applying a thigh tourniquet may reveal previously unidentified outward flow in calf perforators 21. We fill out a form for each limb to record the clinical, aetiological, anatomical and pathological features from the CEAP classification and a clinical severity score defined by an international consensus 22. Reticular veins, uncomplicated varicose veins and CVD with leg oedema correspond to CEAP clinical grades 1-3. Lipodermatosclerosis, healed ulceration and active ulceration correspond to CEAP clinical grades 4-6. FINDINGS IN LIMBS WITH UNCOMPLICATED PRIMARY VARICOSE VEINS (CEAP C1-3) Variations in the anatomy of the saphenofemoral junction and long saphenous vein are so frequent that a case can be made for duplex scanning in most patients. Financial rather than medical considerations leads to restrictions. Limbs with clinical short saphenous reflux show even greater variation in anatomy and we consider that duplex scanning is essential to determine the level for an incision to find the saphenopopliteal junction and to ensure that all tributaries are displayed for ligation. Duplex scanning helps to detect occult CVD in patients with swelling or aching without apparent varicose veins; Tong and Royle 23 found venous obstruction in 15%, superficial reflux in 25% and deep reflux in a further 25%. Our patients with uncomplicated primary varicose veins showed superficial saphenous reflux alone in 85%, superficial and deep reflux in 5% and deep reflux alone in only 1%. There was disease in the long saphenous territory alone in 68%, short saphenous territory alone in 10%, both in 15% and non-saphenous varices in 7%. The source of reflux in the long saphenous territory was from saphenofemoral incompetence in 65%, with added major reflux from pelvic or low abdominal veins in just 3% of these. The saphenofemoral junction was competent in 35%, and the source then was from pelvic or low abdominal veins alone in 25%, thigh perforators in 5% and calf perforators in 5%. The destination for reflux was the long saphenous vein in 90%, or anterolateral or posteromedial tributaries alone in 10%. Most connections from pelvic and abdominal veins were very close to the saphenofemoral junction but occasionally they passed to the long saphenous or its major tributaries further down the thigh. The source of reflux in limbs with varicosities in the short saphenous territory was from saphenopopliteal incompetence in 57%. The saphenofemoral junction was competent in 43%, and the source then was from the Giacomini vein alone in 15%, tributaries from the long saphenous vein in 17% and perforators in 5%. The distribution was to the short saphenous vein alone in 91%, to the Giacomini or gastrocnemius veins as well in 5%, and to these veins alone in 4%. Reflux occasionally was through the vein of Giacomini from the long to short sahenous or the short to long saphenous. The level of the saphenopopliteal junction varied widely from the knee crease to several centimetres above, the most frequent site being 2-3cm above the knee crease. Others have used duplex scanning to show that the level of the saphenopopliteal junction is variable 24,25 and correlates well with findings at operation 24. The saphenopopliteal junction is absent or cannot be seen in approximately 10-15% 26, and the short saphenous vein then usually continues up the thigh as the ascending vein of Giacomini to terminate in the long saphenous, profunda femoris, superficial femoral or pelvic and abdominal veins. Duplex scanning has been used to show audible reflux along key reticular veins from some deeper source even although major connections could not be demonstrated 27,28. Clinical experience shows that it is important to control these first to allow successful treatment of telangiectases. FINDINGS IN LIMBS WITH RECURRENT VARICOSE VEINS We advocate duplex scanning for all patients with recurrent varicose veins, since the anatomy is even more complex than for primary untreated varicose veins. Duplex scanning shows that recurrence after surgery for long saphenous reflux is commonly due to a major connection in the groin 29-31, but that many have connections at other sites 32,33. Many have new varices in the short saphenous system. 64 V OLUME 3(2):November 1999 AUSTRALIAN & NEW Z EALAND J OURNAL OF P HLEBOLOGY

3 Duplex Ultrasound Scanning for Chronic Venous Disease of the Lower Limbs Some consider that duplex scanning after saphenous ligation shows that recurrence is due to neovascularisation 34 but we prefer to incriminate uncontrolled proximal tributaries. It seems logical that repeat surgery should be effective if there is a single large connection from a deep vein to a major saphenous trunk, but that echosclerotherapy or sclerotherapy are better options if there are multiple smaller connections to smaller trunks or tributaries. Our patients with uncomplicated recurrent varicose veins showed superficial saphenous reflux alone in 70%, superficial and deep reflux in 10% and deep reflux alone in 3%. Accordingly, there was deep reflux in 13% in limbs with uncomplicated recurrent varicose veins compared to 6% of limbs with uncomplicated primary varicose veins, and this increased frequency has been shown by others 26,30,35,37 although its significance is not clear. There was disease in the long saphenous territory alone in 50%, short saphenous territory alone in 17%, both in 17% and non-saphenous varices in 16%. Thus, more than one-third actually had new disease in the short saphenous territory. The source was from saphenofemoral incompetence in 35%, and there was also major reflux from pelvic or low abdominal veins in 5% of these. The saphenofemoral junction was competent in 65%, and the source then was from pelvic or low abdominal veins alone in 50%, thigh perforators in 8% and calf perforators in 7%. Others have found a higher incidence of reflux from incompetent thigh perforators 62,99,103,104, 7. The destination for reflux was the long saphenous vein in 72%, or anterolateral or posteromedial tributaries alone in 28%. We had previously shown a difference in patterns according to the original operation 29. There was a single large connection from the saphenofemoral junction or common femoral vein in approximately 50%, which usually passed to an intact long saphenous, vein, and this was more common after long saphenous ligation alone. The other 50% had multiple origins from the common femoral vein or from abdominal or pelvic veins that usually connected to scattered thigh tributaries, and these were more common after long saphenous ligation and stripping. The same considerations apply to the saphenopopliteal junction after short saphenous surgery. Studies have reported saphenopopliteal incompetence in 61%, gastrocnemius incompetence in 34% and other connections in the popliteal fossa in the rest 38, with connections to the short saphenous vein in 75% after ligation alone and to calf tributaries in 64% after short saphenous stripping 39. There have been few objective studies using serial duplex scanning to assess outcome after treatment for CVD. Such a study before and soon after saphenous vein surgery showed that there was persistent reflux down the long saphenous vein in 50% of limbs treated by long saphenous ligation alone and that this was substantially reduced by stripping the vein 40,41. We have found that any intervention that strips or occludes the long saphenous vein from groin to knee leaves reflux in the long saphenous below knee and it remains to be seen whether this will lead to inevitable recurrent varicose veins. Van Rij and colleagues 42 used APG and duplex scanning to confirm excellent results for the first year after long saphenous surgery, but then with frequent late recurrence. No recurrences occurred if there were normal investigations and no residual clinical varices early on, whereas recurrence was almost inevitable if the APG was abnormal or the duplex scan showed deep venous or perforator reflux at the first postoperative scan. Ultrasound-guided echosclerotherapy provides excellent short to medium-term results for varices with major saphenous reflux 43-46, but long-term results will need to be evaluated by serial duplex scanning. FINDINGS IN LIMBS WITH COMPLICATIONS (CEAP C3-6) Duplex scanning is required in these patients if any intervention is contemplated. This is because complications may result from DVI caused by the post-thrombotic syndrome or SVI from major saphenous reflux, and clinical distinction is extremely difficult. In our study, there was superficial reflux alone in 70%, superficial and deep reflux in 15% and deep reflux alone in 10% for limbs with complications. Thus, although the frequency of deep reflux was considerably higher than for uncomplicated veins, most limbs had superficial reflux alone. The Post-thrombotic Syndrome The conventional concept has been that lipodermatosclerosis or venous ulceration result from past deep vein thrombosis (DVT). Recanalisation causes valvular incompetence in deep veins leading to congestion in venous plexuses in the calf, so that blood is expelled at high pressures through perforators during muscle contraction causing damage to overlying tissues. Duplex scanning shows that the site for DVT differs according to the indication for the scan 47. If there are clinical features to suggest DVT then there are equal numbers of above-knee and below-knee thrombi most often involving more than one segment. If the scan is for surveillance in asymptomatic patients, 90% are in the crural veins and most involve only one segment 48. However, duplex scanning now shows the frequency with which DVT in calf veins can propagate to major proximal veins A DVT may recanalise, propagate or recur at the same or other sites. Serial scans in patients treated by conventional anticoagulation show that up to 75% recanalise within 6 A USTRALIAN & NEW Z EALAND J OURNAL OF P HLEBOLOGY V OLUME 3(2):November

4 K A Myers and S R Wood months The prevalence of post-thrombotic deep venous reflux progressively increases over time 54. Studies from the University of Washington show that recanalisation leads to reflux in one-third by one month and two-thirds by two years and this affects each segment down the limb approximately with equal frequency. Reflux is common in sites not initially affected by thrombosis but this is more likely to be transient. Another study at 7-13 years after DVT showed normal findings in 11%, reflux in 46%, obstruction in 8% and both in 35% 59. A further study at 12 years after DVT showed reflux in 33%, obstruction in 10% and both in 50% 60. A concept of venous hypertension from regional reflux in the popliteal and tibial veins has been proposed 61 but the mechanism is not clear. Duplex scanning shows that popliteal and posterior tibial reflux are more common in the affected than in the non-affected limbs of patients with unilateral ulceration, with no difference for any other veins 62. Popliteal reflux is a predictor for ulcer recurrence after conservative treatment 63 or subfascial perforator and superficial venous ligation 64. Duplex scanning showed outward flow in medial calf perforators in two-thirds of limbs with complications, considerably higher than in limbs with uncomplicated primary varicose veins. Perforators with outward flow have a significantly larger diameter in limbs with complications 65. One study found that there was outward flow in 60% of perforators >4mm diameter, 45% for those 3-4mm diameter and 25% for those <3mm diameter 66. A study with duplex scanning showed that 80% of so-called incompetent perforators regain normal competence after stripping the long saphenous vein only 67. Past anatomical studies have shown that some calf perforators have no valves while others have valves that direct flow outwards, and flow in perforators during walking normally occurs in both directions 5,63,64,68. It has yet to be proven that outward flow in perforators causes complications 11,69,70. Primary Venous Disease Many limbs with complications can be effectively managed by treating superficial disease alone. In our study, there was superficial reflux alone in 70%. Another study found that ulceration only occurred if there was reflux down the full length of the saphenous veins, the incidence rising from 8% with long saphenous reflux alone to 14% with both long and short saphenous reflux 71. A further report found that ulceration is more likely to recur if long saphenous reflux persists 64. Others were unable to show any correlation between short saphenous reflux and complications 63 but one study found that 20 legs with lateral ankle ulcers all had short saphenous reflux 72. The situation is even more complex since duplex scanning shows that saphenous stripping frequently corrects deep venous reflux 73,74. Occasionally, duplex scanning shows isolated extensive deep venous reflux that may be suitable for deep vein replacement. However, deep venous reflux is more frequently due to primary disease with normal valves preserved 75 presumably due to weakening and dilatation of deep veins just as for primary varicose veins. CONCLUSIONS Duplex scanning is a simple cost-effective investigation to plan best treatment for CVD. In some instances, it will demonstrate predominant deep venous disease that is best managed by conservative measures without intervention. In others, it will demonstrate the precise anatomy to help plan intervention to interrupt the saphenous junctions, major tributaries or perforators. Measuring the vein diameter will help to judge whether they are best treated by surgery or sclerotherapy. We consider that duplex scanning is essential for limbs with clinical short saphenous reflux, recurrent varicose veins or complications that might require intervention. A case can be made for duplex scanning in all patients seeking treatment for CVD. Figure 1. A duplex scan showing the B-mode appearance of an incompetent calf perforator. The connections to a superficial tributary and a deep tibial vein are seen. REFERENCES 1. Dixon PM. Duplex ultrasound in the pre-operative assessment of varicose veins. Australas Radiol 1996;40: van der Heijden FH, Bruyninckz CM. Preoperative colour-coded duplex scanning in varicose veins of the lower extremity. Eur J Surg 1993;159: Darke SG, Vetrivel S, Foy DMA et al. A comparison of duplex scanning and continuous wave Doppler in the assessment of primary and uncomplicated varicose veins. Eur J Vasc Endovasc Surg 1997;14: McMullin GM, Coleridge-Smith PD. 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