Indications
Suspected deep vein thrombosis (swelling, pain, warmth, a positive clinical score such as Wells), diagnosis and mapping of chronic venous disease (varicose veins, evening oedema, stasis dermatitis, venous ulceration), treatment planning (sclerotherapy, thermal ablation, stripping) and post-treatment follow-up.
Equipment and patient position
- Linear array transducer 5–12 MHz for the whole deep and superficial system.
- For the deep venous system: patient supine, limb slightly externally rotated and unloaded (mild reverse Trendelenburg if the couch allows, to encourage venous distension).
- For superficial reflux: patient standing, supported and with the weight taken on the contralateral limb: the erect position is essential, because reflux must be sought under physiological hydrostatic load and is not demonstrable with the patient supine.
Deep venous system — compression technique
Transverse scanning with serial compression every 1–2 cm along the whole axis: common femoral, femoral, deep femoral (proximal segment), popliteal and tibioperoneal veins of the calf. The diagnostic criterion for thrombosis is failure of the venous lumen to compress completely.
Superficial venous system and reflux assessment
The great saphenous vein is followed from the saphenofemoral junction along its whole medial course in the thigh and calf, as far as the malleolus. The small saphenous vein is followed from the saphenopopliteal junction (variable in height, and to be located specifically in each patient) along the posterior aspect of the calf.
Reflux is documented with pulsed-wave or colour Doppler, applying the dynamic manoeuvres described in the next section along each segment of the saphenous trunk and at the main junctions and perforators.
Dynamic manoeuvres
- Valsalva manoeuvre: the patient makes a forced expiration against a closed glottis; most useful at the saphenofemoral junction and in the proximal segment, where the rise in abdominal pressure is transmitted effectively.
- Manual squeeze and release (compression and rapid release of the calf, or of the segment distal to the point being examined): this produces a wave of antegrade flow on compression and, if the valve is incompetent, a wave of reflux on release. It is the manoeuvre of choice for the mid and distal saphenous vein and for perforators, where Valsalva is less effective.
Si considera emodinamicamente significativo un reflusso di durata ≥ 0,5 secondi (soglia convenzionale più utilizzata in letteratura per il sistema superficiale e le perforanti; per il sistema profondo la soglia comunemente adottata è ≥ 1 secondo).
CEAP classification
The ultrasound report provides the anatomical and haemodynamic data (site and duration of reflux, patency of the deep system) which, combined with the clinical findings, allow the CEAP classification (Clinical-Etiological-Anatomical-Pathophysiological) of chronic venous disease, from class C0 (no visible or palpable signs) to C6 (active venous ulcer).
What to document
- Deep system: complete or partial compressibility segment by segment, site and extent of any thrombosis, and the characteristics of the thrombus (acute or chronic, occlusive or non-occlusive).
- Superficial system: calibre of the saphenous trunks, site and duration of reflux, competence of the saphenofemoral and saphenopopliteal junctions, and significant incompetent perforators.
- Presence of varicose tributaries, tortuosity and sequelae of previous treatment.