Standing duplex: find which junctions and trunks reflux (saphenofemoral, saphenopopliteal, the great and small saphenous veins, perforators), measure the reflux time and the diameters, and draw the map the surgeon or interventionist will treat from.
Orient first
- Reflux is reverse flow lasting longer than a threshold after a calf squeeze or Valsalva — commonly over 0.5 s in superficial veins and 1 s in the femoral and popliteal veins; verify the thresholds used locally.
- The deep veins are examined first: deep vein thrombosis or post-thrombotic deep reflux changes whether superficial treatment is appropriate.
- CEAP classification describes the clinical class; the ultrasound supplies the anatomy and the reflux map.
Acquire the study
- Duplex ultrasound with the patient STANDING (weight on the other leg), a linear probe, colour and pulsed-wave Doppler with distal augmentation.
The manoeuvre
- Deep veins (femoral, popliteal) with the linear probe: compressibility and reflux duration on pulsed-wave Doppler.
- Saphenofemoral junction and the great saphenous vein: reflux time in seconds after calf squeeze, diameter in mm at the junction and mid-thigh.
- Saphenopopliteal junction and the small saphenous vein, including the level of the junction above the popliteal crease in cm.
- Perforators: outward flow in incompetent perforators and their diameter in mm and position from the heel or knee.
- Accessory and non-saphenous sources (anterior accessory saphenous vein, pelvic sources) feeding the varicosities.
What confirms it
- A reflux map: each refluxing segment with its reflux time and diameter.
What licenses you to exclude it
- No reflux beyond threshold in the standing position excludes truncal incompetence as the cause of varicosities.
The classic misread
- Examining supine — reflux is underestimated; the study is done standing.