Endovenous therapy - RFA and EVLT

Endovenous laser ablation (EVLA) and Radiofrequency ablation (RFA) are techniques that have become available over the last 10-15 years for the treatment of varicose veins. As a general rule these techniques will only deal with the underlying cause/source of their varicose veins. These techniques, for most patients, do not remove or destroy the visible varicose veins.

What is radiofrequency ablation (RFA)?

Radiofrequency ablation is a minimally invasive technique to destroy the greater saphenous vein (GSV) in the thigh and/or the small saphenous vein (SSV) at the back of the calf. Both of these veins commonly feed into visible varicose veins. RFA may occasionally be used for other veins such as the anterolateral thigh vein and there is a dedicated RFA device available for treating perforating veins.

RFA is essentially bipolar diathermy. Diathermy refers to electrically induced heat and the bipolar indicates that the electrical current does not pass through the body only through the catheter. By passing an electrical current through a bipolar catheter inside the vein heat is generated and temperatures of 120°C are attained. The heat produced destroys the vein but the procedure relies on direct contact between the catheter and the vein wall. To facilitate the process the vein needs to be as tightly wrapped around the catheter as possible so external compression is applied to the vein using tumescent anaesthesia (injection of fluid containing a local anaesthetic agent) and the leg is elevated to collapse the vein. There is an electrical feedback mechanism integrated into the fibre which can alter the energy delivery to maintain a constant temperature.

There is one dominant RFA device, the VNUS ClosureFast™ (Covidien). There is another device - the Olympus Celon RFITT™ which uses a continuous pull back technique similar to EVLA systems.

What is endovenous laser ablation (EVLA)?

Endovenous laser treatment is a minimally invasive technique to destroy the greater saphenous vein (GSV) in the thigh and/or the small saphenous vein (SSV) at the back of the calf.

Laser is an acronym and stands for "Light Amplification by Stimulated Emission of Radiation. Laser light is monochromatic (single wavelength) light produced from a laser medium and then amplified to produce a powerful beam

There are at least 5 types of laser available for use in EVLA. The different lasers vary in the wavelength of the laser light produced and there are some theoretical advantages and disadvantages of each of these different types of lasers. There is little evidence to support one laser over another. Presently there are lasers working at 810, 940, 980, 1320 and 1470nm wavelengths. EVLT™ is a particular brand of device that is used for EVLA.

When are RFA/EVLA used in the treatment of varicose veins?

RFA and EVLA sound impressive, but they are merely alternative techniques that can be used to destroy the greater saphenous vein in the thigh or the small saphenous vein at the back of the calf when they are incompetent and need to be ablated. RFA or EVLA are alternatives to stripping of these veins and also replace the disconnection of veins performed through a small incision either in the groin or behind the knee (saphenofemoral and saphenopopliteal disconnection).

Sclerotherapy, which is a chemical foam injected to damage the vein, can also be used to occlude the GSV and SSV.  In EVLT and RFA the veins are destroyed by heating them to a high enough temperature to damage the vein wall.

Should I have RFA or EVLA to treat my varicose veins?

Suitable patients being treated with RFA and EVLA will generally have greater saphenous vein (along thigh) and or small saphenous vein (back of calf) reflux. These techniques require a vein that is reasonably straight in order to pass the laser fibre or RFA catheter up the vein. It is also important that fluid can be injected around the vein to separate it from the skin and surrounding structures so they do not get burned, but this is a very unlikely event.

Which veins cannot be treated by RFA or EVLA?

Large visible tortuous varicose veins cannot be treated. Thread and reticular veins cannot be treated with RFA or EVLT and are usually best treated with sclerotherapy. Veins being treated need to be reasonably, but not absolutely, straight to enable the catheters to pass.

How are RFA and EVLA performed?

These techniques are very similar but there are some minor differences.

The first part of the procedure involves inserting a catheter (fine tube) into the vein to be treated (cannulation). This is usually done by using ultrasound to guide a fine hollow needle into the vein. A wire is then passed into the vein through the hollow of the needle and the needle removed along the wire. The wire is then passing from outside the skin into the vein. The hollow catheter is then threaded on to the part of the wire on the outside and passed along the wire into the vein. Once the catheter is in position the wire is removed. This is known as the Seldinger technique and is a common method of obtaining access to many structures in the body. Ideally the catheter should be positioned down the leg as far as the abnormal flow is present. If necessary a small incision can be made to obtain access to an appropriate vein if this is difficult using the ultrasound technique.

The radiofrequency catheter or laser fibre is then passed up the vein and positioned no closer than 2cms from the saphenofemoral or saphenopopliteal junctions. These are junctions between the superficial and the deep veins and the distance is to minimise the possibility of damage to the deep veins, but maximise the length of vein to be treated. The video below is an animation of the technique.

In both techniques it is essential that the vein being treated is separated from the surrounding tissues by injecting fluid around the vein (ultrasound guided tumescent anaesthesia). This is for two reasons. Firstly if the procedure is being performed under local anaesthetic with the patient awake the injections prevent pain being felt when the vein is being treated. Secondly, both techniques heat the vein and the heat needs to be dispersed without damaging any of the tissues surrounding the vein. The liquid that is injected is usually a very dilute local anaesthetic and large volumes are injected, often up to 300mls of fluid per leg. This is a simple and straightforward process.

This is not a painless procedure and if being performed with the patient awake many practitioners will give patients nitrous oxide (laughing gas) or other inhaled pain killers to minimise discomfort.

This brochure details other aspects of the procedure

Are EVLA and RFA equally successful?

Surgery remains the gold standard (Enzler, 2010) against which other techniques must be judged and recently studies have been published comparing these techniques. At one year all treatments were effective but the highest technical failure rate was in patients undergoing sclerotherapy (16%) with the lowest in the surgery and RFA groups (both at 4.8%). Interestingly the mean pain scores after intervention were highest in the EVLA group and lowest in the RFA group with surgery in between. The mean time off work was between 3 and 4 days. It is clear that surgery and RFA at least are comparable treatments especially when surgeons use tumescent anaesthesia..

At present the durability of these procedures in the longer term is unknown. Although EVLA can ablate the GSV (Sharif et al 2006), longer term follow up has not been performed in large numbers of patients (Mundy et al, 2005). Consequently, EVLA has not been adequately compared with the gold standard of conventional surgery and results may deteriorate with longer term follow up. There are also many different EVLA lasers on the market all with their own theoretical advantages and proponents and with different working wavelengths. There is reasonable evidence now that RFA particularly with the newer ClosureFast technology is a slightly superior procedure when compared with EVLA. One study using the VNUS ClosureFast™ RFA device demonstrated an over 99% success rate at 2 years.

Neither EVLA or RFA have been shown more effective than surgical techniques when it comes to the medium to long term risk of recurrent varicose veins developing. It is also important to remember that EVLA and VNUS Closure are only a replacement for the high tie and stripping part of conventional surgery This avoids a groin incision and minimises discomfort and deals with the source of the visible veins. The visible veins themselves can either be removed through tiny incisions at the same treatment or be managed with injection treatments at a later appointment. In some patients no further treatments are necessary. When comparing the overall procedure rather than just the success of the GSV obliteration concomitant (at the same time) phlebectomy (removal of the actual visible varicose veins) seems to be better. It reduces the need for secondary procedures and significantly improves quality of life and the severity of venous disease (Carradice, 2009).

Globally, many clinicians are involved in treatment of varicose veins. These include vascular surgeons, general surgeons, sclerotherapy specialists, dermatologists, and cosmetic medicine practitioners   There is a risk of recurrent varicose veins, whoever is involved in your care and whatever claims they may make. There are two main reasons for this. Firstly the nature of the disease will always put patients at risk of recurrent veins. It is a life-long tendency and over years new veins can appear whatever the treatment, no matter how carefully performed. Secondly, some techniques if not applied correctly may lead to increased risk of early recurrence.

Recurrence rates are difficult to compare because definitions of what constitutes recurrence vary from study to study. For instance many patients will have persistent or will develop new thread (spider) veins. Spider veins (telangiectasia) are present in the majority of people over the age of 50 years. The development of larger veins is less common.

What are the possible complications of RFA or EVLA?

Recurrent varicose veins - there is no treatment for varicose veins which is immune from the possibility of new veins developing. This is because although all the veins that are problematic can be treated it is not possible to remove the underlying tendency to develop varicose veins

Nerve damage - this would be an unusual complication providing the procedure is performed correctly; but occasionally nerves supplying the skin can be heated which may cause some tingling or numbness

Burning of the skin or surrounding tissues - provided plenty of tumescent anaesthesia is used and the procedure performed correctly this is unlikely.

Burning or heat injury to the deep veins is possible but very rare as a number of measures are taken to avoid this problem.

DVT- There is a risk of deep vein thrombosis (DVT) with any surgery, but the risk is of the order of 1-2% after these procedures.

Failure of the procedure - in perhaps 1-2 people in every 100, the vein being treated doesn't completely obliterate following RFA. The procedure can be repeated if necessary.

All of the above complications are also potentially occur with open surgery and probably to a slightly greater extent.

Useful links

http://en.wikipedia.org/wiki/Radiofrequency_ablation

http://en.wikipedia.org/wiki/EVLT

References

Rasmussen LH, Lawaetz M, Bjoern L, Vennits B, Blemings A, Eklof B. Randomised clinical trial comparing endovenous laser ablation, radiofrequency ablation, foam sclerotherapy and surgical stripping for greater saphenous varicose veins. Brit J Surg 2011; 98: 1079-87.
Enzler MA, van den Bos RR. A new gold standard for varicose vein treatment? Eur J Vasc Endovasc Surg 2010; 39: 97-98.
Sharif MA et al. Endovenous laser treatment for long saphenous vein incompetence. Brit J Surg 2006; 93: 831-835
Mundy L, Merlin TL, Fitridge RA, Hiller JE. Systematic review of endovenous laser treatment for varicose veins. Brit J Surg 2005; 92: 1189-94.
Carradice D, Mekako AI, Hatfield J, Chetter IC. Randomised clinical trial of concomitant or sequential phlebectomy after endovenous laser therapy for varicose veins. Brit J Surg 2009; 96: 369-375.
Hingorani AP, Ascher E, Markevich N et al. Deep venous thrombosis after radiofrequency ablation of greater saphenous vein: a word of caution. J Vasc Surg 2004; 40: 500-4.

 

 

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