A 38-year-old woman with a 10-year history of lower limb varicose veins presents for evaluation. She reports heaviness, aching, and occasional skin changes over the medial ankle. Which investigation is most appropriate to assess the functional status of the saphenofemoral junction and determine candidacy for surgical intervention?

Explanation

## Functional Assessment of Varicose Veins: Doppler Ultrasonography **Key Point:** Doppler ultrasonography with reflux assessment is the gold standard investigation for evaluating varicose veins and determining the site(s) of venous incompetence. ### Why Doppler Ultrasonography? 1. **Non-invasive and safe** — no radiation or contrast 2. **Identifies incompetent perforators** — critical for surgical planning 3. **Assesses reflux** — detects reverse flow in saphenous veins (>0.5 seconds = pathological) 4. **Evaluates saphenofemoral junction (SFJ)** — determines if saphenous vein stripping is indicated 5. **Guides minimally invasive procedures** — essential for endovenous ablation planning 6. **Reproducible and widely available** — standard in most vascular labs ### Doppler Findings in Varicose Veins | Finding | Interpretation | |---------|----------------| | Reflux duration >0.5 sec (standing) | Pathological venous incompetence | | Reverse flow in saphenous vein | Indicates SFJ or mid-thigh incompetence | | Incompetent perforators | Guides sclerotherapy or ablation | | Patent deep veins | Rules out DVT; essential pre-operative | | Calf perforator incompetence | Associated with skin changes (lipodermatosclerosis) | **Clinical Pearl:** The **Valsalva manoeuvre** during Doppler ultrasound increases intra-abdominal pressure and accentuates reflux, making incompetence more evident. This is essential for detecting SFJ incompetence. **High-Yield:** Duplex ultrasound (B-mode + Doppler) is **mandatory before any surgical intervention** for varicose veins to: - Confirm superficial venous incompetence - Exclude DVT - Map incompetent perforators - Assess deep venous patency ### Pre-operative Assessment Algorithm ```mermaid flowchart TD A[Symptomatic varicose veins]:::outcome --> B[Duplex ultrasound]:::action B --> C{SFJ incompetence?}:::decision C -->|Yes| D[Saphenous vein stripping/ablation]:::action C -->|No| E[Perforator incompetence?]:::decision E -->|Yes| F[Perforator ligation/ablation]:::action E -->|No| G[Sclerotherapy alone]:::action B --> H{DVT present?}:::decision H -->|Yes| I[Anticoagulation; defer surgery]:::urgent H -->|No| J[Proceed with planned intervention]:::action ``` **Tip:** Duplex ultrasound should be performed **standing** to maximise reflux and improve diagnostic accuracy. [cite:Bailey & Love's Short Practice of Surgery 27e Ch 56]