RADIOFREQUENCY ABLATION (RFA) and ENDOVENOUS LASER ABLATION (EVLA)
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What is radiofrequency ablation (RFA)?
What is endovenous laser ablation (EVLA)?
When are RFA/EVLA used in the treatment of varicose veins?
Should I have RFA or EVLA to treat my varicose veins?
Which veins cannot be treated by RFA or EVLA?
How are RFA and EVLA performed?
Are EVLA and RFA equally successful?
Are EVLA and RFA better than surgery?
What are the long term results of RFA and EVLA?
What are the possible complications of RFA or EVLA?
References
Useful links
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. For most patients these techniques will only deal with the underlying cause/source of their varicose veins. These techniques, in general, do not remove or destroy the visible varicose veins. Other endovenous techniques are also available and these include ablation with steam and more recently using a surgical cement.
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. It 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 in this context 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 85-120°C can be 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 compression is applied to the vein using tumescent anaesthesia and external compression 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 EVLT 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 all with the supporters and detractors. 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 and there is no level 1 evidence from blinded randomised trials. Presently there are lasers working at 810, 940, 980, 1320 and 1470. EVLT™ is a partcular 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. The equivalent surgical technique is high ligation and stripping of the vein which physically removes the vein. In sclerotherapy chemical foam is injected to damage the vein. In EVLT and RFA the veins are destroyed by heating them to a high enough temperature to damage the vein wall.
RFA or EVLA are alternatives to stripping 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).
Should I have RFA or EVLA to treat my varicose veins?
Suitable patients being treated with EVLA and RFA will generally have greater saphenous vein (along thigh) and or small saphenous vein (back of calf) reflux. They will need a vein that is reasonably straight in order to pass the laser or RFA fibre 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.
Which veins cannot be treated by RFA or EVLA?
Large visible tortous 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/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 vein,s but maximise the length of vein to be treated.
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 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 and also prevented from burning all the surrounding tissues including the skin. 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 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.
Are EVLA and RFA equally successful?
Surgery remains the gold standard (Enzler, 2010) against which other techniques must be judged and for the first time a randomised trial has compared results in a group of 500 patients from Denmark comparing surgery, EVLT, RFA and foam sclerotherapy. 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 EVLT 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, but rather surprisingly EVLT causes more pain than both.
At present the durability of these procedures in the longer term is unknown, they require expensive additional equipment and do not physically remove the GSV. Although EVLT 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, EVLT 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 EVLT 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 EVLT. Both techniques have similar success rates. A pooled analysis of results of RFA showed an average success rate at destroying the vein treated of 80% at 5 years. These figures were slightly worse than EVLA but compared EVLA with older RFA technology. There is only one study available using the VNUS ClosureFast™ RFA device but this demonstrated an over 99% success rate at 2 years.
Neither EVLT or RFA have been shown more effective than tried and tested surgical technique when it comes to the medium to long term risk of recurrent varicose veins developing. It is also important to remember that EVLT and VNUS Closure are only a replacement for the high tie and stripping part of conventional surgery. Separate procedures are required to deal with any other varicose veins and this may take the form of foam sclerotherapy or surgical phlebectomy. 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). One particularly awkward situation to treat with EVLT or RFA is the patient who has sizeable veins running across the front and outside of the thigh (antero-lateral thigh veins). If these originate right at the sapheno-femoral junction then EVLT or RFA will not be effective.
A further new technique to remove bunches of varicose veins in the leg especially the calf is also available. The Triflex device involves sucking many of the veins out of the leg using a custom made instrument. This technique appears to have no particular advantage and has not been shown to be superior to conventional avulsions and still involves making cuts in the leg (Chetter IC et al 2006).
Globally, many clinicians are involved in treatment of varicose veins. These include sclerotherapy specialists, dermatologists, appearance medicine practitioners and general surgeons. 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. It is a life-long (probably) inherited 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 recurrence.
Recurrence rates are difficult to compare because definitions of what constitutes recurrence vary from study to study. For instance if the development of thread veins is considered a recurrence, then the majority of patients will develop recurrent veins. This is because thread veins are so common and present in the majority of people over the age of 50 years. The development of larger veins is less common.
Are EVLA and RFA better than surgery?
Both produce results that are comparable or better than surgery in the trials performed to date. It is important to remember that in these trials surgeons will have performed other procedures besides the high tie and strip that RFA/EVLA can replace. Surgery is a single treatment that usually produces a good result and it is only occasional patients that need any postoperative injection treatment.
In patients with a large anterolateral thigh vein RFA/EVLA will not be effective as usually the source of reflux is at the saphenofemoral junction in the groin and the fibres cannot be used so close to the deep veins.
RFA is more costly than surgery but some of these costs may be offset by a slightly quicker return to work (Subramonia, 2009) but tumescent anaesthesia was not used in this study and it will lessen the after effects of surgery when used.
What are the long term results of RFA and EVLA?
There is no doubt that they can be effective in the short to medium term but longer term durability is not known. It is important that when results are reported they are reported as part of a randomised trial so we can have confidence that comparisons between treatments are valid.
What are the possible complications of RFA or EVLA?
Recurrent varicose veins
Nerve damage
Burning of the skin or surrounding tissues. Burning or heat injury to the deep veins
DVT- one report on VNUS radiofrequency ablation has rather worryingly highlighted a high rate of deep venous thrombosis (16% or 1 in every 6 patients), many of whom required significant intervention (Hingorani AP et al, 2004), but this does not seem to have occurred in other practices.
Failure of the procedure
Last updated> 23 October, 2011
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http://en.wikipedia.org/wiki/Radiofrequency_ablation
http://en.wikipedia.org/wiki/EVLT