From Distance Measurement to Anatomic Landmark: The Cranial Tributary-based Flush Ablation Protocol for Anatomic Landmark-Guided Catheter Tip Positioning in Great Saphenous Vein Ablation.

PURPOSE: To evaluate the feasibility, safety, and mid-term outcomes of the Cranial Tributary-based Flush Ablation (CTFA) protocol, using the first effective cranial tributary (FECT) as the primary landmark for catheter tip positioning (CTP). MATERIALS AND METHODS: Consecutive patients undergoing radiofrequency (RFA) or microwave ablation (MWA) with the CTFA protocol between June 2023 and March 2024 were retrospectively included. Under transverse ultrasound, the catheter was retracted until the FECT orifice (>5 mm distal to the saphenofemoral junction) disappeared; predefined distance-based positioning served as fallback; all received pharmacological thromboprophylaxis. Primary endpoints were technical success, FECT-guided applicability, endothermal heat-induced thrombosis (EHIT) 2-4, and anterior accessory saphenous vein (AASV) recurrence. RFA and MWA were compared by propensity score matching in the 97-limb follow-up cohort; random forest-based imputation and Kaplan-Meier analysis addressed missing data. RESULTS: Technical success was 100% (159/159). FECT-guided applicability was 80.5% (128/159; Scenario 1: 11.3% [18/159], Scenario 2: 69.2% [110/159]); 31 limbs (19.5%, Scenario 3) required the distance-based fallback. Mean CTP distance was 15.7 mm. EHIT-2 occurred in 1.3% (2/159), with no EHIT-3/4. At 18 months, duplex follow-up was available for 97/159 limbs (61%); crude AASV recurrence was 8.2% (8/97), with a Kaplan-Meier recurrence-free survival of 93.40%. Great saphenous vein occlusion was 100%, 98.6%, and 95.9% at 1 week, 6 months, and 18 months. Stump-length evolution (biphasic) and clinical outcomes were comparable between modalities. CONCLUSION: Using the FECT as the primary landmark, the CTFA protocol demonstrated feasibility and acceptable mid-term safety; whether it improves procedural consistency requires prospective validation.