VI. Innovations in phlebology
VI. Innovations in phlebology
Fully percutaneously created or surgically inserted artificial vein valves in CVD treatment – research status and first clinical data
Steve Elias (US)
The Self Valve study analyzed the SailValve, a new self-expanding deep venous valve concept based on a single polytetrafluoroethylene cusp floating up and down in the bloodstream like a sail acting as a flow regulator and allowing minimal reflux to reduce thrombogenicity. Deployment was technically feasible in all 10 iliac veins and all were patent directly after placement. No perioperative or postoperative complications occurred. Ascending phlebograms in the follow-up animals confirmed the patency of all valves after 2 or 4 weeks. Descending phlebograms showed full function in 5 of 8 valves. Limited reflux was seen in 1 valve (4-week group) and the function in the remaining 2 valves (2- week group) was insufficient because of malpositioning. No macroscopic thrombosis was noted on histology. Histology in the follow-up groups revealed a progressive inflammatory reaction to the valves.
The next system for endovascular valve creation is the BlueLeaf Endovenous Valve Formation System, which uses a catheter system, a nitinol dissector, a needle assembly, and performed under intravascular ultrasound guidance. The procedure has 3 main steps: (i) gain subintimal access with a 16 Fr sheath in the common femoral vein after identification of the appropriate valve site with intravascular ultrasound; (ii) perform a hydrodissection; and (iii) create the valve. This method can be used to create monocuspid valves, bicuspid valves, and potentially multilevel valves as well. The trial is currently enrolling outside of the United States, with 15 patients in Australia and New Zealand. The inclusion criteria will be patients who have the most severe disease with C5 and C6 disease and significant deep vein reflux.
Another system is the VenoValve. Hancock Jaffe Laboratories has developed a bioprosthetic venous valve, the VenoValve®, to correct or reduce venous reflux within the deep venous system. The device comprises a biologic valve mounted in a supporting metal frame that will allow for a straightforward surgical insertion of the bioprosthesis into the femoral vein. It is a monocuspid valve with a diameter of 8 to 10 mm. There has been a successful experience of implantation of valves into the external jugular vein in sheep (4 cases) and the common femoral vein in dogs (4 cases). A Columbian surgeon Jorge Ulloa has implanted the valve into 8 patients with C5/C6 range into the femoral vein (Elias/ Gasparis are the principal investigators). The results of the 90-day observation period are available, showing positive results so far.
Recent development in the dedicated venous stents – lessons learned and future direction
Steven Black (UK)
A meta-analysis conducted in 2016 showed that the patency rates of venous stenting were high (79% to 98%). Now there are eight different stenting systems: Ziver-Vena (Cook), Vici (BSCI), Venovo (BD), Wallstent (BSCI), Sinus-Venous (Optimed), Sinus-Oblicuos (Optimed), Abre (Medtronic), and Blueflow (Plus Medica). The FDA has only approved the Wallstent, Venonvo, and Vici. Stents are very different in their design and cannot be compared straight away. The VIRTUS exploration data (VICI venous stent in 170 patients) showed an 84% primary patency rate and a 98.8% safety end point rate. The VERNACULAR study (Venovo Venous stent – 170 patients) showed an 88.3% primary patency rate and a 93.5% safety end point rate.
Stents can be implanted with a closed cell, open cell, hybrid cell, and braided cell that will all be very different in terms of the level of crush resistance, flexibility, radial strength, deployment, scaffolding, diameter, and length. A randomized double-blind study comparing medical treatment vs iliac vein stenting in chronic venous disease was conducted in 2018. At the 6-month follow-up, the mean VAS pain score declined from a median of 8 to 2.5 in patients receiving stents and from 8 to 7 in patients receiving only medical treatment (P<0.001). The venous clinical severity score decreased from a median of 18.5 to 11 after stenting and from 15 to 14 with medical treatment (P<0.001). The 36- item short-form health survey (0-100) improved from a total median score of 53.9 to 85.0 with stenting and 48.3 to 59.8 after medical treatment (P<0.001).
Stenting success is dependent on many factors, such as stent choice, placement errors, technical mistakes, level of inflow, and clotting system. Currently, more randomized controlled trials are needed for acute deep vein thrombosis, for chronic venous obstruction comparing different stents, and more data is needed about new stents and systems for stenting.
Hyaluronian injection based treatment in phlebology – why and when?
Johann Chrisof Ragg (Germany)
From a patient’s point of view, we should do much more to prevent venous disease or to heal in a vein-preserving way with minimal effort and minimal cost. There are three mechanical causes of primary venous insufficiency: embryonic valve lesions, time/age, and pressure, which induces valve decompensation and stasis and is related to valve degeneration. To prevent and cure valvular lesions of all origins, internal vein compression via injection of hyaluronic acid can be used.
The main ideas of internal compression are to improve the early stages of valve decompensation by eccentric and concentric lumen modification. Hyaluronic acid is a well-established product in esthetic treatments, with the best tissue compatibility of all known synthetic fillers and a simpler and smoother injection than autologous fat. For injections, it is preferably to use a safety cannula to prevent intravenous injection.
Johann C. Ragg discussed eccentric valvuloplasty, which is used to improve valve function in asymmetrical lesions, concentric valvuloplasty, which is used to restore valve function in symmetrical lesions, and hemodynamic venoplasty, which is used to normalize pressure irrespective of valves. Recent results from 2018-2019 showed 42 technically successful cases of concentric valvuloplasty for incompetent valves of the great saphenous vein via injection of monophasic hyaluronic acid (4 to 6.5 mL), and, at the 6-month followup, 40 of the 42 cases (95.2%) had orthograde flow. Data from 2018-2019 showed that eccentric valvuloplasty was successful in 17 cases, with hemodynamic success after 3 months in 13 of the 17 cases (76.5%) and after 1 year in 9 of the 13 cases (69.2%).
In addition, other areas for using hyaluronic acid have been demonstrated; for example, using it instead of a saline solution during vein ablation for safety reasons or using it to perform a more precise sclerofoam treatment. All studied variations of internal vein compression by perivenous hyaluronic acid are safe and effective. The different veinshaping modalities, in particular the vein-preserving ones, open new perspectives to learn about hemodynamics and early stage treatment.
First percutaneous – non invasive – vein ablations using high intensity focused ultrasound (HIFU)
Alfred Obermayer (Austria)
Insufficient veins can be treated in a completely noninvasive manner using high-intensity focused ultrasound (HIFU), as has been demonstrated with the SONOVEIN device. The visualization and treatment unit of the device contains a 3-MHz HIFU transducer for treatment, and embedded 7.5-MHz ultrasound for visualization, and a single-use membrane and liquid for cooling and coupling. Preclinical ex vivo and in vivo animal studies with HIFU showed that the histology results for the veins are identical to those induced by radiofrequency.
A prospective clinical study assessed 50 legs (62% [31/50] were recurrent and 74% (33/50) were classified as C4-C6) by treating recurrences, neovascularization at the stump, perforators, great saphenous vein, anterior accessory saphenous veins with no adjunctive methods (sclerotherapy, etc) with a 3-month follow-up period. The procedure was feasible for all patients. Preliminary results showed that the procedure could be performed without anesthesia (only used in a few cases), without sedation or other medications, and there were no significant side effects (skin changes, skin burns), and, for cases of very mild and transient dysesthesia, there was no thrombosis or pulmonary embolism and no need for anticoagulation medication.
The main advantages of HIFU are the it can be used to treat over skin with severe atrophic disorders (ulcers), it has an extreme precision for heat deposition, it does not require a sterile field, it can be performed without anesthesia or sedation, it can treat very tortuous structures, and it is a safe procedure with a high level of patient satisfaction. The main limitations of HIFU include a lack of long-term studies and structures within 5 mm from the skin may need subcutaneous infiltration.
Transcutaneous obliteration of varicose veins by ultrasound: HIFU and Cavitation solutions
Rene Milleret (France)
There are two biological effects of high-intensity focused ultrasound (HIFU): thermal (heating of tissues at temperatures up to 100° C, like laser ablation) and cavitation (in a liquid, microbubbles, which burst and free a lot of energy, like foam sclerotherapy). Rene Milleret demonstrated his model of HIFU, with two different probes for the treatment of telangiectasia and large veins. A successful series of obliterations have been performed on rabbit ears and saphenous veins in sheep with this model. The limitations regarding the thermal effects are that tumescence is often needed, the vein must be compressed, and it is time consuming, and, regarding the cavitation effects, it is less precise, leads to hemolysis, and the reopening rate is not yet known . Indications for use are due to HIFU effects: thermal (valvuloplasty, stumps (recurrences), perforators, malformations) and cavitation (trunks, building tributaries). Endovenous techniques will be seen as an intermediate stage between aggressive stripping and noninvasive transcutaneous ablation.
Telemetric vein diagnostics: how does technology enable patient compliance?
Willy Chi (US)
Compliance with the use of compression stockings is close to 50%. The SOX trial showed that, during 24 months, only 69.1% of patients reported using compression stocking and only 55.6% used stockings more than 3 days per week. In a report, two devices for telemetric vein diagnostics were described; the purpose of the devices is to improve compliance with compression stockings by monitoring the wearing of compression knitwear.
The Thermotrack® device, which has a cylindrical form (16 mm×6 mm) that is enclosed in stainless steel, started as a sensor in the food industry to measure temperature of food products; it has a 97% accuracy rate with a limitation for the external temperature of >23oC. The temperature curve date from ThermotrackR can be exported in an excel format to local storage. The device has a long battery life of 10 years. Another device, VenoSense® is a plastic disk (41 mm×25 mm) that includes a piezoresistive sensor that measures pressure in mm Hg. When more than 5 mm Hg of pressure is detected, a numerical number 1 generated. If the pressure is less than 5 mm Hg, VenoSense® suggests that a patient is not wearing compression stockings and a 0 is generated. The pressure data from VenoSense® can upload automatically to the cloud in an excel format. The manufacturer is now trying to miniaturize the circuit to 16×4 mm. The battery has a short life of 6 months. All devices are waterproof.
SFALT: Sclerofoam-assisted laser therapy for saphenous refluxes: an innovative tumescence-free technique
Francesco Zini (Italy)
Thermal ablation by endovenous laser treatment of varicose veins with radial fibers is a minimally invasive procedure with good outcomes. However, the literature reports that up to 52% of the procedures are painful and not aesthetic since hematomas or ecchymosis can occur along the treated saphenous area after endovenous laser. There is no correlation between the minimally invasive approach of endovenous laser and the large amount of liquid that is injected with tumescent anesthesia. In addition, the vein is compressed in the groin and, due to liquid from the tumescent anesthesia between the saphenous fascia, the vein is no longer visible and therefore no longer monitored with ultrasound. Tumescent anesthesia is not free from potential complications.
To improve these limitations, Francesco Zini invented SFALT (ScleroFoam-Assister Laser Treatment), an innovative tumescence-free technique. SFALT is a hybrid technique combining foam sclerotherapy and endovenous laser ablation in a tumescence-free approach. It consists of introducing an endovenous laser fiber into the great saphenous vein, shrinking it for a single cm at 200 J/cm. After a shrunk plug is created, keeping the fiber stuck in it, 5 cc of foam sclerotherapy (Tessari method, 1% polidocanol, or 1% sodium tetradecyl sulfate) are injected through the same 6 Fr endovenous laser introducer. The consequent spasm allows a subsequent endovenous laser–mediated shrinkage by means of a significantly reduced fluence. A clinical and sonographic follow up was done at 1 and 3 weeks.
Francesco Zini described the results after 850 personal cases since October 2014. No major or minor complications were reported. At the mid-thigh, the standing great saphenous vein caliber decreased from a preoperative value by more than 50%. There were no statistical differences between sodium tetradecyl sulfate and polidocanol. At follow-up, there were only 3 complete recanalizations.
The SFALT approach is feasible and safe, with potentially interesting outcomes. This technique offers the chance of a possible tumescence free great saphenous vein treatment, even in case of major calibers vessels.
