EMWA stands for “endovenous microwave ablation”. It is a new method for treating varicose veins under local anaesthetic.
The first case in the UK was performed in February 2019 at The Whiteley Clinic in Guildford.
Varicose veins have two major components.
The first are the obvious lumpy veins on the surface. These are the “varicose veins”.
The second are the underlying veins. These are the “truncal veins” and “incompetent perforator veins”.
The underlying veins are invisible from the surface. However, these underlying veins cause most of the problems. They cause swelling of the ankles, aching of the legs, red or brown stains around the ankles and eventually leg ulcers. Therefore it is essential to treat these underlying veins first followed by the lumpy veins on the surface.
In the past, doctors “stripped” away these underlying veins. However, stripping causes most of these veins to grow back again. When veins re-grow after stripping, they fail to grow new valves. Therefore the new veins are immediately varicose veins. We prove this and published the information in 2007 and 2014.
In 1999, Mark Whiteley introduced endovenous surgery into the UK. Over the last 20 years, he has shown that treating the underlying veins with the correct amount of heat energy can give a permanent cure. His methods destroy the deficient veins by ablation. This means that they cannot come back again, provided the surgeon uses the correct energy levels. This is the basis of The Whiteley Protocol. The evidence for this was proven in our published 15-year results.
Microwave ablation is an endovenous treatment. This is a similar treatment approach as laser ablation and radiofrequency ablation. “Endovenous” means that the treatment device is inside the vein during treatment. A local anaesthetic is the only sort of anaesthetic needed. This means that patients can walk home between 30 and 60 minutes after the treatment.
The local anaesthetic numbs a patch of skin. The surgeon uses ultrasound to visualise the target vein. They then push a needle through the numb patch and into the vein. A wire is then passed through the needle. A catheter is passed over the wire and into the vein. This is the entry route for the microwave catheter.
Tipping the patient “head down” empties the vein of blood. When the microwave device is inside the vein, the surgeon injects local anaesthetic around the vein. This stops the heat from damaging nearby structures or overlying skin.
The microwave is turned on and the correct energy level is set for the patient. The microwave heats water in the cells of the vein wall. This heat denatures proteins in the cells, permanently ablating the vein. We have performed research to show the optimal energy power for each size of vein.
Over the last 20 years, research has proven that endovenous thermal ablation is the most effective way of treating varicose veins. Thus NICE guidelines recommend endovenous thermal ablation as the first line treatment. Endovenous thermal ablation literally means heating the vein sufficiently to ablate it (permanently close it) from within.
Mark Whiteley performed the first case in the UK in March 1999. The device was the VNUS Closure catheter. This catheter had electrodes to pass radiofrequency electrical current into the vein wall.
Subsequent radiofrequency ablation devices use a coil that generates heat within the vein. Although radiofrequency ablation can be very effective, it does rely upon the catheter being in contact with the vein wall.
There are also lasers that can ablate the vein using heat. Different lasers use different wavelengths. Some of these heat blood, some heat protein and some heat water. The optimal lasers are those that heat the water.
Because laser uses “light” it is not essential that the laser device is in contact with the vein wall. In addition, most lasers fire the energy forwards. The more sophisticated lasers now pass the energy outwards from the tip. As the vein lies around the catheter tip, it is much more accurate and logical to use these “radial firing” lasers.
Microwave has all of the advantages of radiofrequency ablation as well as the latest lasers. It does not have to be in contact with the vein wall. The power passes from the side of the tip directly into the vein wall. Microwave affects the water in the cells in the vein wall.
However, because microwave is perfectly controllable and does not emit any “light”, there is no need for any laser precautions. Hence there is no need for any laser proof room, laser warning signs nor laser eye protection.
As such, the new microwave treatment for varicose veins (EMWA) appears to have several advantages over the current endovenous thermal ablation techniques.
Microwave treatment of varicose veins is still very new. Thus there is not as much experience in using microwave as there is with laser and radiofrequency ablation.
Although laboratory research from The Whiteley Clinic has shown that it will be effective in ablating the veins, the device itself is larger.
Research presented by Tim Fernandez-Hart and Mark Whiteley has suggested that a larger device might have some advantages in treating diseased veins. However, it does mean that some patients with smaller veins might not be suitable for this technique.
Microwave is an exciting new development in varicose vein surgery. It is definitely useful to treat large varicose veins and big perforator veins. However, more experience and research will determine the exact role of microwave varicose veins treatment in patients with smaller varicose veins.