Servier – Phlebolymphology

Is all heat the same and does catheter design matter?
M. S. Whiteley

Endothermal ablation is less invasive than traditional surgery with reduced side effects and a faster recovery period. Many different devices have been developed by different companies, but questions remain regarding whether the heat produced differs between different devices and how the catheter design influences the energy distribution to the vein wall.

The linear endovenous energy density (LEED) is a measure of the heat energy delivered to the vein wall in Joules (J)/cm of vein treated. The power of the device is measured in watts (W) and one W is defined as one J/sec. So the LEED could be adapted by setting the power of the device or the time of the withdrawal.

Some devices (radiofrequency and steam) use direct heating by transmitting the thermal energy by direct conduction to the vein wall. Others (lasers) use indirect heating by transferring electromagnetic energy into thermal energy. Some of these devices require direct contact with the vein wall to have their effect (radiofrequency) and others that do not need any contact (laser and steam) to deliver the energy to the wall. It seems that to achieve better results, blood should be absent from the section of vein being treated, otherwise the heat energy will be used to heat the blood and not the vein wall.

Successful thermoablation requires transmural death of all layers of the vein wall to ensure complete fibrosis and permanent ablation. To achieve this goal, the thermal energy should be spread radially and deeply, avoiding a high power with a fast pullback.

From these arguments, it is suggested that bare-tip laser fibers are more likely to cause perforation and inadequate treatment of vein sections, and that devices requiring direct contact with the vein wall may get inadequate thermoablation results in case of aneurysmal or thrombotic veins.

The direct contact devices and the radial lasers do not spread thermal energy, thereby restricting the thermoablative effects to extend no more than 1 to 2 mm proximal from the tip.

In conclusion, the heat used to ablate veins can be applied directly to the vein wall, or not, with the same effect because the effect of the heat on the vein wall depends only on the LEED delivered and transferred. Catheter design plays an important role for the technical success of the procedure and ensures the optimal transfer of thermal energy to the vein wall.

Endovenous laser treatment (EVLT) never touch.
L. Kabnick

The laser side effects are most likely caused by laser-induced vein wall perforation with extravasation of blood into the surrounding tissue. These perforations are more common with a higher power and greater linear endovenous energy density (LEED). The hemoglobin-based wavelengths produce more short-term side effects than longer wavelengths. There are fewer side effects in terms of pain and bruising with 980 nm than 810 nm at the same power and with 1320 nm at 5 W compared with 8 W. The New York University (NYU) pilot studies is an observational nonrandomized study that compares 810 nm, 980 nm, and 1470 nm lasers using bare-tip vs the NeverTouch fiber. The conclusion is that water-based lasers (1470 nm) allow decreased power and energy to be delivered, and more importantly, that covered fibers allow decreased power density leading to less vein perforations.

EVLT for perforating veins with NeverTouch Direct Laser (NTDL).
M. Whiteley

The diagnosis and treatment of incompetent perforating veins (IPV) are controversial. The author argues that some patients with varicose veins only have IPVs, some varicose veins go away after an IPV treatment, some IPVs are associated with the recurrence of varicose veins, and that IPVs are regularly found to be the cause of the recurrence. Many treatments have been used to treat IPVs such as open surgery with the Linton and Cockett technique, subfacial endoscopic perforator surgery (SEPS) described by Hauer, and more recently the transluminal occlusion of perforators (TRLOP) technique reported by Whiteley. TRLOP now uses a laser fiber with water as the chromophore. TRLOP using the NeverTouch Direct Laser (NTDL) seems to offer many advantages: it is a safe and quick procedure if used at 10 W where the same device could be used for truncal veins and there is no risk of needle damage.

EVLT Biolitec.
M. Cough

For the author, the best results with endovenous laser treatment (EVLT) are obtained with standardization of the procedure and by using a linear endovenous energy density (LEED) of 70 J/cm (which means a power of 14 W/cm for 5 seconds). Using a 1470 nm radial fiber, Pannier reported no pain, no need for analgesia, no ecchymosis in 44%, 50%, and 80% of patients, respectively (Pannier et al. VASA. 2013;39(3):249-255). Schwars compared radial fiber with bare fiber lasers and found fewer ecchymosis (P<0.0001) and less analgesia (P>0.04) with radial fibers. For the author, his 1470 nm radial fiber is equivalent to VNUS Closure. The 1470 nm radial fiber with 2 rings gave more homogeneous energy distribution, less sticking, less postoperative pain, ecchymosis, and paresthesia in the series by Maurins (Maurins et al. Int Angiol. 2009;28(1):32-37). Approximately 78% of patients do not need analgesics and it seems there is no benefit of compression post-EVLA. In conclusion, the 1470 nm radial fiber is equivalent to VNUS Closure fast on pain, bruising, paresthesia, and outcome. The laser could be useful for tortuosity and junctional treatment with the possibility of using a guidewire. In addition, 1470 nm fibers have also a lower cost than VNUS closure fast fibers.

CLASS trial.
J. Brittenden

The primary objectives of the CLASS (Comparison of LAser, Surgery and foam Sclerotherapy as a treatment for varicose veins) study was to compare surgery, ultrasound-guided foam sclerotherapy (UGFS), and endovenous laser ablation (EVLA) combined with foam to residual nontruncal varicosities for the treatment of varicose veins. The quality of life at 6 months was assessed through the Aberdeen Varicose Veins Questionnaire (AVVQ), EuroQOL five dimensions questionnaire (EQ-5D), and 36-Item Short Form Health Survey (SF-36) questionnaires, and the cost-effectiveness was evaluated as the cost per quality adjusted life year (QUALY) gained. The CLASS conclusions were that UGFS is associated with significantly lower improvement in quality of life, more complications compare with EVLA, reduced ablation rates at 6 months, and, on modeling, was not cost-effective at 5 years compared with either EVLA or surgery. EVLA had fewer complications and less cost-effectiveness compare with surgery with the same efficacy.