From the Guidelines
The characteristic feature of great saphenous vein reflux is reversed blood flow in the great saphenous vein, typically lasting longer than 0.5 seconds, as defined by duplex US evaluation 1. To diagnose this condition, a duplex ultrasound examination is performed while the patient is standing, which may involve the patient standing on 1 leg while the other leg is scanned, or alternatively, maneuvering patients to 60 degrees of Trendelenburg if the former is not tolerated 1. The test involves compressing and releasing the calf muscle, which normally causes blood to flow upward towards the heart. In patients with great saphenous vein reflux, the ultrasound will show blood flowing backwards (towards the feet) for an extended period. Specifically, reflux lasting more than 0.5 seconds in the great saphenous vein is considered abnormal and indicative of venous insufficiency, resulting from primary degenerative changes within the venous wall and valves or as sequela of acute DVT causing destruction of venous valves 1. Understanding this characteristic is crucial for accurate diagnosis and appropriate treatment planning, which may range from conservative measures like compression stockings to more invasive procedures such as endovenous ablation or surgery, with endovenous thermal ablation being a recommended first-line treatment for nonpregnant patients with symptomatic varicose veins and documented valvular reflux 1. Key aspects of duplex US evaluation include:
- Condition of the deep venous system, GSV, small saphenous vein (SSV), and accessory saphenous veins
- Presence and location of clinically relevant perforating veins and extent of possible alternative refluxing superficial venous pathways
- Evaluation of venous structures via both transverse and longitudinal planes
- Documentation of presence, absence, and location of reflux, with measurement and reporting of abnormal reflux times 1.
From the Research
Characteristics of Great Saphenous Vein (GSV) Reflux
- The reflux volume in the GSV increases caudally from the saphenofemoral junction to the knee level 2
- Blood flow from competent tributaries is a likely contributor to the distally increasing reflux volume in the incompetent GSV 2
- Saphenofemoral junction (SFJ) reflux with tributary involvement and sparing of the GSV trunk occurs in 8.8% of chronic venous disease patients 3
- SFJ reflux of the GSV is associated with the most severe form of the disease, with an odds ratio of 2.96 4
- The intensity of venous reflux in the saphenofemoral junction is correlated with morphological changes of the GSV, including diameter alterations 5
- Velocity and peak flow are better parameters for evaluating reflux intensity, as they are correlated with GSV alterations and are associated with the disease's clinical severity 5
Reflux Patterns and Risk Factors
- SFJ reflux of the GSV is associated with severe clinical severity, while competent SFJ of the GSV with reflux from proximal veins is associated with mild to moderate clinical severity 4
- Obesity increases the frequency of severe chronic venous insufficiency 2.7 times, and being a woman also increases the frequency of more severe disease 1.3 times 4
- The correlation between reflux time and clinical severity is weak, while velocity and peak flow are better parameters for evaluating reflux intensity 5