Guidelines for the assessment of the venous circulation of the lower limbs

The purpose of the examination is to verify a reflux or a superficial and/or deep venous thrombosis. The investiga- tions are different in the two cases. The deep venous circulation should always be assessed.Verification of a reflux Methods of investigations: Continuous wave Doppler (CWD) — Duplex scanning (DS) — Color-coded duplex scanning (CDS) — Intravascular ultrasound (IVUS) — Standard radiography (Xray) — Angiography by computed tomography (AngioCT) — Angiography by magnetic resonance (AngioMR) — Plethysmography (PG) — Photo-plethysmography (PPG) The methods of first choice are the ultrasound examina- tions or photo- plethysmography (PPG). The two types of study should be considered complementary and not alter-natives.CDS is presently the most useful and reliable means for studying the venous system of the lower limbs. Its sensitivity and accuracy are close to 100% in all path- ological conditions, both acute and chronic. The morphological data, which with the more recent de- vices presents a resolution power of 0.3 mm, highlights the finest features of the vascular wall and of the valves. Adding the hemodynamic data, the examination pro- vides information that is static, but mainly dynamic in short periods of time. The ultrasound examination allows to detect a reflux, its origin, its entity and to evaluate its oriented direction and which veins are interested. It allows to investigate the single superficial or deep vein, identifying it based on its anatomic site, and allows the origin and axis of the reflux to be completely demonstrated. This technique also provide repeatable and reliable quantitative data (e.g., the length of time of the reflux during the Valsalva maneuver performed under standard conditions; the measure of the reflux peak velocity RPV). Venous outflow obstruction is also studied by duplex ultra- sound and chronic changes in deep and superficial veins following deep venous thrombosis may be noted