Optimal diagnostic investigation of the veins is the basis for successful treatment

These investigations are non-invasive and painless

Additional methods of examination

The following two investigational procedures can be used to obtain additional information on the pressure and blood flow in the veins, to assess whether or not the muscle pump is functioning well and to assess the success of treatment. They are both painless, non-invasive examinations.

Photoplethysmography (PPG)

Examination of the vein function by means of photoplethysmography

Examination of the vein function by means of photoplethysmography

Photoplethysmography (PPG), also known as light reflexion rheography (LRR), uses infrared light to check vein function. It determines the venous refill time, which allows the examiner to assess the condition and function of the veins.

A sensor with an infrared light source is attached to the skin on the inside of the lower leg. The amount of infrared light that is reflected depends on the filling of the veins in the skin and changes during a defined movement.

For this examination, the patient sits down and is asked to raise and lower the toes 10 times, in order to activate the muscle pump and transport the blood in the leg veins towards the heart. This action empties the veins in the skin, as the blood cannot be replaced so quickly. The foot is then held still and the veins refill relatively slowly if they are healthy. With venous disease, the valves no longer close properly, allowing some of the blood to continually flow backwards, thus filling the veins much more quickly than when they are healthy. The shorter the refill time, the more severe the venous disease.
The refill time in healthy legs is more than 25 seconds, but refilling takes less than 10 seconds in the case of severe vein disorders.

Venous occlusion plethysmography (VOP)

Measurement of volume changes in the leg veins by means of venous occlusion plethysmography

Measurement of volume changes in the leg veins by means of venous occlusion plethysmography

This method measures changes in volume in the leg veins when the venous outflow is suddenly occluded. It allows the inward and outward blood flow to be assessed.
A strain gauge is attached to the lower leg to measure changes in volume while a blood pressure cuff above the knee is used to regulate the blood flow. The patient lies down for this examination. The legs are elevated for 3 minutes directly before the measurements start.
When the blood pressure cuff is inflated, the circumference of the leg increases, as blood no longer flows back to the heart through the veins, but continues to be supplied by the arteries. The inflated cuff causes the veins to fill to the maximum. The strain gauge measures the expansion of the lower leg.

If the veins are healthy, they can take up a certain additional volume of blood, normally 2.5-5mL/100mL tissue. When varicose veins are present, the dilated veins can hold more blood than normal.

The blood pressure cuff is then deflated and the venous blood flows out of the legs. Normal venous drainage is 35-100 mL/100mL tissue. Rapid drainage shows that the veins are patent (open). If a vein is occluded (blocked) for any reason, such as thrombus, the blood takes longer than normal to drain away. With pronounced varicose veins, on the other hand, the venous outflow is increased.

Phlebography is only seldom used nowadays

Phlebography is an invasive investigative procedure that involves injecting contrast medium (dye) containing iodine into a vein and taking X-rays. The contrast medium makes the veins and any pathological changes visible. Today, phlebography is performed only in special cases that cannot be diagnosed by other means.