Flow augmentation study

Annually about 1 per 1000 people in Western European countries develop deep
venous thrombosis (DVT). In about 25% of cases the caval, iliac and common
femoral veins are affected. After a DVT the body will break down the cloth in
order to recanalize the affected veins, however, in 70% of cases where the
aforementioned vein segments are involved, inadequate recanalization occurs.
This can vary from minor post-thrombotic changes to a remaining full occlusion
of the vessel. If inadequate recanalization occurs, patients can develop
debilitating symptoms with significant loss of quality of life, comparable to
Chronic Obstructive Pulmonary Disease and heart failure.
In these types of patients, stenting can be performed with good clinical
results and significant improvement in clinical scoring systems and quality of
life. The first day after this intervention, patients receive intermittent
pneumatic compression stockings (IPCS) to prevent early stent occlusion due to
immobilisation.
Although stenting has been found to be an effective treatment, treatment
becomes more difficult when post-thrombotic changes reach below the femoral
confluence. An endophlebectomy has to be performed, where the common femoral
vein is opened and post-thrombotic scarring tissue is surgically removed.
However, post-thrombotic tissue is still present in the femoral and deep
femoral vein, for which we have no adequate treatment options at the moment.
Following this procedure, a temporary arteriovenous fistula (AVF) is created to
ensure proper inflow in the operated and stented tract to prevent reocclusion.
Despite these measures and adequate post-operative anticoagulation, occlusion
or stenosis of the affected tract still occurs in the early phases
post-operatively due to thrombogenic circumstances, leading to additional
interventions.
Since the geko can augment venous flow, we woner whether the IPCS, which we now
use during the first two days after intervention and the Geko can stimulate
flow in the same way. This system is easy to use and can be worn while walking.
Therefore, we would like to investigate if the geko augments venous flow in
post-thrombotic limbs and compare it to the IPCS we use now, which has never
been performed in this patient group 1.

In patients with a hybride procedure we will investigate whether the Geko (with
occluded AVF) will augment flow like an open fistula.
Additionally, a better patient selection with identification of patients who
will not benefit from treatment will likely also lead to fewer complications.
The Treadmill Pilot Study (NL44588), which has been completed in our centre,
already showed us that venous pressure is significantly higher in diseased
limbs, compared with the contralateral healthy limbs, during walking, standing,
and in the supine position. Follow-up has to tell us though whether pressure
can be predictive of complications. Pressure in supine position can be easily
measured during intervention, though differences in the supine position are
relatively small with a lot of overlap. A follow-up to the Treadmill Pilot
Study should therefore include supine pressure measurements with provoked flow.
Higher flow means larger variation in pressure and might therefore lead to a
practical parameter that identifies patients at risk for occlusion.

Knowing what device to use to provoke flow in such a study will be an
additional benefit of testing whether IPCS and geko augments flow.

In conclusion, to improve post-operative care, diminish reocclusion, and
further our research in finding a parameter useful for better patient treatment
selection, this study is necessary to investigate whether geko can augment flow
in post-thrombotic limbs.

Primary Objective: The primary objective of this study is to identify whether
the Geko system can augment flow compared to IPCS in post-thrombotic limbs
before after stenting.(group 1) In group 2 we want to identify whether the Geko
with occluded fistula stimulates blood flow in the same degree as the hybrid
treated patients. (group 2)

This is a cross-sectional interventional study in patients with a
post-thrombotic obstruction undergoing a percutaneous procedure (PTA,
stenting). Flow will always be measured in the external iliac vein, 2 cm above
the level of Poupart*s ligament. Patients will be tested before the
percutaenous procedure, 1-2 weeks after the *ntervent*on and 6 week after
discharge. The order of device use (IPCS an Geko device) will be randommized.
If a patient randomises for Geko, the Geko device and the standard treatment
with IPCSs will be compared. I(n group 2 we will compare GEKo with occluded
fistula with open fistula.

The measurements will start in supine position after a five minutes* rest. The
Geko device will be activated and after five minutes the flow will be measured
for a period of 5 minutes. Following this first measurement there will be
another resting of 5 minutes. Then the IPCSs/ fistula will be activated and
flow will be measured for 5 minutes following the 5 minutes of device
activation.
The Geko device will be activated at a frequency of 1 Hz (this is standard for
device).

Geko device versus IPCS or open fistula

The burden of this study is relatively low as both geko and IPCS are
non-invasive, will be administered for a very short period of time and patients
do not need to visit the hospital. The geko device can cause some mild
discomfort or irritation of the skin though.