One-year results of treatment of incompetent truncal veins and incompetent perforators using high intensity focused ultrasound (HIFU)

ABSTRACT

Introduction, Objectives, and/or Purpose: Incompetent truncal and perforating veins of the legs contribute to a variety of conditions collectively called chronic venous insufficiency (CVI). Symptoms and signs of CVI adversely affect patient's quality-of-life. These can range from tired and heavy legs, through varicose veins, swollen ankles, fasciocutaneous damage all the way to leg ulceration. International guidelines recommend the treatment of venous reflux using endovenous thermal ablation as a first-line, and foam sclerotherapy as a second-line treatment. Both of these ablate the incompetent vein. There has been a push towards less invasive techniques, but most of these still involve endovenous cannulation. High-Intensity Focused Ultrasound (HIFU) is a completely non-invasive ablative technique. The HIFU technique uses to ultrasound systems within one machine. The first, a greyscale ultrasound with a colour flow capability, is used to identify the target vein and to target the focused ultrasound. The second is a conical focused ultrasound beam, that focuses on a point approximately 5 mm high by 3.6 mm circumference. In this focus area, temperatures can rise to 70-90°C. This is sufficient to ablate biological tissue. Objectives: (1) To assess the success of using HIFU for the treatment of incompetent truncal veins (GSV, SSV, AASV). (2) To assess the success of using HIFU for the treatment of incompetent perforator veins. (3) To determine the success of adjuvant foam sclerotherapy with of after HIFU, as a treatment protocol. Methods: A retrospective audit of 55 patients treated with HIFU using the Sonovein device (Theraclion, Paris, France) between May 2019 and September 2020 was performed. Due to the COVID-19 pandemic, and consequent travel restrictions and lockdowns, not all patients could return for follow-up DUS at the planned time intervals (1-2 weeks, 6- 8 weeks, 6 months, 1-year post-treatment). DUS outcome of the treated vein was graded 1. complete success (complete atrophy of the target vein) 2. partial success (≥ 1 patent section;none giving rise to recurrent varicose veins / subclinical reflux not requiring treatment) 3. partial failure (≥ 1 patent section giving rise to significant recurrent varicose veins) 4. complete failure. Initially, we performed HIFU of incompetent veins and then completed the procedure with ultrasound-guided foam sclerotherapy. Later, the foamsclerotherapy was delayed and only used if required.We analysed the success rate of HIFU alone in those patients who had only HIFU treatment. In those who had additional foam sclerotherapy, we analysed the success rate of HIFU and foam sclerotherapy starting from the date of the foam sclerotherapy, regardless of whether it was performed on the same day as HIFU or subsequently. Results: Fifty patients (femalemale 3911) returned for at least one follow-up scan giving a 90.9% response rate for at least 1 scan. Due to the COVID-19 pandemic, and consequent travel restrictions and lockdowns, not all patients could return for follow-up DUS at planned time intervals (1-2 weeks, 6-8 weeks, 6 months, 1-year post-treatment). There were 78 legs treated, and 41 truncal veins and 146 incompetent perforator veins. Truncal veins Twenty-nine patients (41 truncal veins in 35 legs) had at least one follow-up scan. Ten patients (15 truncal veins) had concurrent foam sclerotherapy, and nineteen patients (26 truncal veins) did not. Of these nineteen patients, seven patients (10 truncal veins) received foam sclerotherapy within one year of having HIFU treatment. Twelve patients (16 truncal veins) did not receive foam sclerotherapy at all. Those patients having HIFU only showed an 83.3% (15 out of 18) closure at 6- 8 weeks (Figure 1). The results for HIFU and foam sclerotherapy are shown in Figure 2. Despite difficulties in getting patients back for scans, closure rates of 83.3% and 100% were found between 9 and 12 months and over 12 months, respectively. Perforator veins Forty-three patients (146 perforator veins in 68 legs) attended at least once. Suc essful ablation was seen in 88% at 6 months and 70% at one year in those not having foam sclerotherapy, and 83.3% and 100% in those having HIFU and foam sclerotherapy. Conclusions: High Intensity Focused Ultrasound (HIFU) is a new technique that can treat incompetent truncal and incompetent perforator veins extracorporeally. We have reported the one-year results of patients having either HIFU alone, or HIFU combined with ultrasound guided foam sclerotherapy. Allowances need to be made for the sporadic follow-up due to the COVID-19 pandemic, and also the fact that we changed our protocols of treatment as we got more experienced. Hence, even although we are reporting what is in effect the learning curve for this technique, the outcomes are not dissimilar from the early outcomes from endovenous thermal ablation. Increased speed of treatment with a corresponding reduction in the need of any local anaesthetic is being introduced, and further audits will be performed in the future to ensure the success rates are maintained or improved.