Venous Tests

Venous tests are non-invasive procedures that assess how well the leg veins return blood to the heart — whether the venous valves are competent and whether blood drains freely without obstruction. VasoGuard performs venous studies using photoplethysmography (PPG) and air plethysmography, which detect changes in limb blood volume without ultrasound imaging or needles.

• Non-invasive and painless
• Assess venous valve competence (reflux) and venous outflow
• Help screen for chronic venous insufficiency and venous outflow obstruction

VasoGuard measures venous function with two complementary plethysmographic methods rather than ultrasound imaging:

Venous refill time (photoplethysmography). A PPG sensor on the lower leg tracks blood volume in the skin. The patient performs a series of dorsiflexions (a calf-pump exercise) to empty the leg veins, and the system then measures how long the veins take to refill. A rapid refill points to valvular reflux; an optional tourniquet helps distinguish superficial from deep venous reflux.

Venous capacitance and outflow (air plethysmography). Calf and thigh air cuffs measure the rise in limb volume when venous outflow is briefly occluded, and the rate of drainage when it is released — screening for venous outflow obstruction such as deep vein thrombosis or post-thrombotic changes.

• PPG venous refill time, with optional tourniquet to localize reflux
• Air-cuff measurement of venous capacitance and maximum venous outflow
• Automated waveform capture, on-screen measurement, and reporting

Venous testing supports:

• Screening for chronic venous insufficiency and valvular reflux
• Screening for venous outflow obstruction (e.g., deep vein thrombosis or post-thrombotic syndrome)
• Documenting venous function to help guide and monitor treatment

Non-invasive venous studies are a practical, point-of-care complement to duplex ultrasound — quick to perform and useful for screening and functional assessment.

VasoGuard includes two built-in venous studies, run as guided protocols with high-resolution waveform display, on-screen measurement, and report export:

• Venous Reflux — PPG venous refill time, with an optional thigh, above-knee, or below-knee tourniquet to separate superficial from deep reflux.
• MVO / Venous Capacitance — air-plethysmography measurement of maximum venous outflow and segmental venous capacitance to screen for outflow obstruction.