Radiofrequency ablation for uncomplicated varicose veins

M S Gohel and A H Davies. RFA for uncomplicated varicose veins Original article
Principles of radiofrequency ablation
Scientific principles
The underlying principle of RFA involves the delivery
of thermal energy derived from an electric
current to the venous segment to be treated. This
is achieved using a bipolar endovenous catheter
with a typical power of 2–4 W, which is used to
generate temperatures of 85–1208C. As the procedure
relies on direct contact between the RFA
catheter and the vein wall, it is essential that the
vein is emptied of blood during ablation (achieved
using Trendelenberg position, use of tumescent
anaesthesia and extrinsic compression). There is
an in-built feedback mechanism, which evaluates
the vein wall impedance and can adjust the
energy delivery accordingly to ensure that the
fibre temperature remains consistent.
Ex vivo histological studies of venous segments
treated with RFA demonstrated homogeneous
intimal and medial thermal ablation and disintegration.
This differed from veins treated with
endovenous laser ablation, where major perivenous
tissue ablation and vein wall perforations were
present. 1
Available devices
The current market leader for endovenous RFA
devices is VNUS w Medical Technologies Inc. (San
José, CA, USA). The VNUS Closure TM catheter has
been available for nearly a decade and requires a
continuous pullback technique. This was com-
monly used with a tight compressive rubber
bandage (Esmark w , Hygenic Corp., Akron, OH,
USA) to facilitate venous emptying during treatment.
In 2006, VNUS launched the ClosureFast TM
segmental ablation catheter, which allows RFA of
superficial veins in 7 cm segments, thus eliminating
the continuous pull-back technique (Figure 1). The
segmental ablation has the theoretical advantages
of greater consistency in the vein treatment and
increased speed of ablation as each 7 cm segment
can be treated in 20 seconds. It should be noted
that VNUS also market a specific stylet device
(VNUS RFS TM stylet) for the ablation of incompetent
perforating veins. All VNUS catheters may be
used with the VNUS RFG Plus TM generator
(Figure 2).
The Olympus Celon RFITT TM (Olympus Medical
Systems, Hamburg, Germany) is an alternative
RFA system which has been upgraded recently
(Figure 3). The system uses the continuous pullback
technique and claims to treat venous segments
at a pull-back speed of 1 cm/s, although clinical
studies using this new device are scarce.
Description of technique
Although there are broad similarities between the
various endovenous therapies, the location of treatment,
type of anaesthetic and numerous other
factors will be dictated by the personal preference of
clinicians (see Delivering a radiofrequency ablation
varicose vein service below). The generic technique
for RFA can be summarized in the following steps:
Figure 1 Illustration of the segmental ablation technique using the VNUS ClosureFast TM catheter.
(Reproduced with permission from VNUS)
Phlebology 2009;24 Suppl 1:42–49 43