Safety and efficacy of microwave versus laser ablation in the treatment of varicose veins of lower extremities (MOST Trial): a multicenter, open-label, non-inferiority, randomized controlled trial

Background: Endovenous microwave ablation (EMA) is an emerging minimally invasive therapy for varicose veins; however, robust evidence comparing EMA to established endovenous laser ablation (EVLA) remains limited. This multicenter randomized controlled trial aimed to evaluate the non-inferiority of EMA versus EVLA for the treatment of great saphenous vein (GSV) insufficiency. Materials and methods: A total of 180 patients with GSV reflux were randomized 1:1 to either EMA or EVLA. The primary outcome was GSV occlusion rate at 6 months postoperatively (non-inferiority margin, 10%). Secondary outcomes included occlusion rates at 1 week, 3 months, and 12 months postoperatively; changes in Venous Clinical Severity Score (VCSS) and Aberdeen Varicose Vein Questionnaire (AVVQ) scores; procedural metrics; and safety outcomes. Results: EMA demonstrated non-inferiority to EVLA at 6 months postoperative GSV occlusion rates [Full Analysis Set (FAS): 94.32% vs. 90.00%, risk difference (RD) 4.32%, 95% confidence interval(CI): − 4.00% to 13.06%; Per-protocol Set (PPS): 97.65% vs. 95.29%, RD 2.35%, 95% CI: − 4.08% to 9.47%, P<0.001 for both analyses). Both groups exhibited comparable and significant reductions in VCSS (EMA: 4.18 ± 2.24 to 1.10 ± 1.18; EVLA: 4.13 ± 2.50 to 0.93 ± 1.0) and AVVQ scores (EMA: 6.03 ± 3.21 to 1.54 ± 2.28; EVLA: 6.30 ± 3.68 to 1.12 ± 1.72) over 12 months (time effect p<0.001; group-by-time interaction P > 0.05), indicating equivalent symptom relief. Kaplan-Meier analysis revealed no significant difference in the time to GSV recanalization between the groups during long-term follow-up (log-rank test, P = 0.15). Device-related adverse events were rare (EMA, 2.27% vs. EVLA, 2.22%; P = 1.00), with no device deficiencies or serious adverse events related to the surgery or device. Conclusion: EMA is non-inferior to EVLA for GSV closure at six months, with similar safety profiles and quality-of-life outcomes. These findings support EMA as a viable alternative to EVLA, warranting further investigation of its long-term durability.