Safety and efficacy of endovenous thermal ablation for treatment of symptomatic varicose veins during summertime.

Background: Traditionally, varicose vein treatment is predominately performed during the colder seasons. However, data whether higher outdoor temperatures affect the outcome and/or complication rate of endovenous thermal ablation (ETA) for treatment of symptomatic varicose veins are missing. Patients and methods: In this observational study, the medical records of all patients who had ETA of the great saphenous vein (GSV), accessory saphenous vein (ASV), or small saphenous vein (SSV) between September 2017 and October 2020 were reviewed. Results: In total 846 ETA interventions in 679 patients with 1239 treated truncal veins and an average length of 69 cm phlebectomy were included. The highest temperature recorded on and within the first 14 days after treatment was on average 19.0°C (SD±7.2°C) with a minimum and maximum of -1°C and 35.9°C. Interventions were categorized according to the recorded temperature (<25°C n=584; 25-29.9°C n=191; and ≥30°C n=71). The occlusion rates were excellent (99-100%) across groups. Despite a significantly higher proportion of patients with obesity, personal history of superficial vein thrombosis and length of phlebectomies in the high temperature groups, no significant difference regarding days of work loss, patients' satisfaction or complications including bleeding or thromboembolic events was observed. Infections were rare (0.8%), but more frequently observed in the 25-29.9°C group (2.6%; p=0.058). No infection was observed in the ≥30°C group and pain 6 weeks after the intervention was even lower (VAS 0.5±1.0 and 0.5±1.2 vs. 0.0±0.1, p=0.008). Conclusions: Given the minimal invasive nature of ETA, our results can reassure clinicians and patients that ETA varicose vein treatment is possible and safe throughout the year, even on hot summer days. A non-significant trend to more infections was observed but was not associated with other adverse outcomes such as prolonged analgetics intake or inability to work.