Is code 36475 medically necessary for a 50-year-old patient with a chronic wound on the right lower leg and varicose veins of bilateral lower extremities, given the absence of a complete Doppler report with measurements and reflux times?

Medical Necessity Assessment for CPT Code 36475

Code 36475 (endovenous radiofrequency or laser ablation) is NOT medically necessary for this patient because critical documentation requirements are missing, specifically the absence of a complete Doppler ultrasound report with reflux duration measurements and vein diameter measurements at specified anatomic locations.

Critical Missing Documentation

The following essential criteria are not documented and are mandatory for medical necessity:

• Reflux duration measurements: The clinical note mentions "moderate reflux noted bilaterally" but does not provide the specific reflux time in milliseconds at the saphenofemoral junction (SFJ). Medical necessity requires documented junctional reflux duration of ≥500 milliseconds at the SFJ or saphenopopliteal junction 1, 2.

• Vein diameter measurements: No specific GSV diameter measurements are documented below the SFJ. The Aetna criteria explicitly require vein size ≥4.5 mm in diameter measured by ultrasound below the saphenofemoral junction (not valve diameter at junction) 1, 2.

• Exact anatomic landmarks: Duplex ultrasound reports must explicitly document where measurements were obtained with specific anatomic landmarks to confirm the presence of junctional reflux and adequate vein diameter for ablation 1.

What the Clinical Documentation States

The clinical note indicates:

• "Bilateral GSV moderately dilated with moderate reflux noted bilaterally" - this is insufficient
• "LE venous duplex no DVT, B/L dilation and reflux noted" from 1/20/25 - lacks specific measurements
• The note does NOT state reflux times (e.g., 600ms, 1200ms) or specific diameters (e.g., 6.2mm at mid-thigh level)

Why These Measurements Matter

• Reflux duration >500 milliseconds correlates with clinical manifestations of chronic venous disease and predicts benefit from intervention 1.
• Vein diameter directly predicts treatment outcomes and determines appropriate procedure selection - veins <4.5mm may be better treated with foam sclerotherapy (which has different success rates of 72-89% at 1 year) rather than thermal ablation 1, 3.
• Vessels <2.0mm treated with sclerotherapy had only 16% primary patency at 3 months compared with 76% for veins >2.0mm 3.

Clinical Criteria That ARE Met

The patient does meet several important clinical criteria:

• Chronic wound (venous ulcer) on right medial calf - this represents intractable ulceration secondary to venous stasis, which is one of the qualifying conditions 1.
• 3-month trial of compression therapy - patient has worn compression stockings for 3 months with improvement in edema, meeting the conservative management requirement 1, 2.
• Symptomatic presentation - swelling, discomfort, and non-healing wound affecting quality of life 1.

What Must Be Done Before Approval

To establish medical necessity, the following documentation is required:

1. Recent duplex ultrasound (within past 6 months) with specific measurements:

   • Reflux duration at bilateral SFJs (must be ≥500ms) 1, 2
   • GSV diameter measurements below the SFJ at specific anatomic landmarks (must be ≥4.5mm) 1, 2
   • Assessment of deep venous system patency 2

2. Complete ultrasound report must document:

   • Direction of blood flow 2
   • Assessment for venous reflux with exact duration in milliseconds 1, 2
   • Venous obstruction status 2
   • Condition of deep venous system 2
   • Extent of refluxing superficial venous pathways 2

Treatment Algorithm When Criteria ARE Met

If proper documentation confirms the required measurements, the evidence-based treatment sequence would be:

• First-line treatment: Endovenous thermal ablation (radiofrequency or laser) for GSV reflux when diameter ≥4.5mm with documented SFJ reflux ≥500ms achieves 91-100% occlusion rates at 1 year 1, 3.
• For venous ulcers specifically: Endovenous thermal ablation need not be delayed for additional compression therapy trials when ulceration is present, as ulceration represents severe disease (CEAP C6) warranting intervention 1, 3.
• Expected outcomes: Technical success rates of 91-100% within 1 year, with improved wound healing when underlying venous reflux is corrected 1, 4.

Common Pitfall to Avoid

Clinical presentation alone cannot determine medical necessity - multiple studies demonstrate that not all symptomatic varicose veins have saphenofemoral junction reflux requiring ablation 1. The presence of a chronic wound and "moderate reflux" on physical examination does not substitute for objective ultrasound measurements with specific numeric values.

Recommendation for This Case

Request a complete venous duplex ultrasound report with:

• Specific reflux times in milliseconds at bilateral SFJs
• Specific GSV diameters in millimeters at defined anatomic locations below the SFJs
• If these measurements meet thresholds (≥500ms reflux, ≥4.5mm diameter), then CPT 36475 would be medically necessary given the presence of chronic venous ulceration 1, 2, 4