What are the characteristics of saphenopopliteal (saphenous vein and popliteal vein) reflux?

From the Guidelines

Saphenopopliteal reflux is characterized by backward blood flow in the small saphenous vein at the saphenopopliteal junction, where it connects to the popliteal vein behind the knee, with reflux defined as retrograde flow duration of more than 500 milliseconds in the superficial and deep calf veins, and more than 1,000 milliseconds in the femoropopliteal veins 1. Key characteristics include:

• Reverse flow direction: Blood flows away from the heart instead of towards it
• Location: Occurs at the saphenopopliteal junction in the posterior knee area
• Duration: Reflux lasting more than 500 milliseconds is considered significant
• Associated symptoms: May cause varicose veins, leg swelling, aching, and skin changes in the lower leg
• Diagnosis: Typically identified using duplex ultrasound imaging, which is the first assessment of the lower extremity venous system and should include direction of blood flow, assessment for venous reflux, and venous obstruction 1 This reflux occurs due to incompetent valves in the small saphenous vein, allowing blood to flow backwards under the influence of gravity when standing. It's an important component of chronic venous insufficiency and can contribute to various lower leg vascular issues if left untreated. Management may include compression therapy, lifestyle modifications, or interventional procedures depending on severity and symptoms. Some of the key considerations for diagnosis and management include:
• The use of duplex US to evaluate the condition of the deep venous system, GSV, SSV, and accessory saphenous veins, as well as the presence and location of clinically relevant perforating veins and extent of possible alternative refluxing superficial venous pathways 1
• The importance of measuring and reporting abnormal reflux times, with reflux defined as retrograde venous flow >500 ms 1
• The potential for concomitant arterial occlusive disease, which is frequently not recognized, and the need for arterial vascular characterization in some cases 1

From the Research

Characteristics of Saphenopopliteal Reflux

• Saphenopopliteal reflux is a condition where blood flows backwards from the popliteal vein into the saphenous vein, causing varicose veins and other symptoms 2, 3, 4, 5.
• The reflux can occur at the saphenopopliteal junction (SPJ), which is the connection between the saphenous vein and the popliteal vein 2, 4, 5.
• Studies have shown that reflux at the SPJ can be detected using handheld continuous wave Doppler and confirmed with duplex scans 2, 6.
• The location of reflux in the saphenous vein does not affect outcomes of vein ablation, according to one study 3.
• Another study found that the insufficient small saphenous vein shows a high frequency of axial reflux from the deep into the saphenous vein, with an indication for high ligation or thermal ablation at the level of the SPJ or immediately distal to the inflow of muscular veins depending on the junction type 4.
• Recurrent varicose veins after short saphenous vein surgery can be caused by incompetence of the short saphenous vein, gastrocnemius vein, popliteal area vein, or popliteal vein 5.

Diagnosis and Treatment

• Duplex ultrasound is a useful tool for assessing recurrent venous reflux in the popliteal fossa and determining the level of an incompetent saphenopopliteal junction 5.
• Hand-held Doppler can be used to accurately mark the SPJ for surgery, guided by a routine duplex scan, eliminating the need for a second duplex scan 6.
• Treatment options for saphenopopliteal reflux include ligation and division of the SPJ, as well as endoluminal thermal ablation of the insufficient saphenous vein 2, 4.