Venous claudication treadmill trial

Venous claudication (VC) is the feeling of tightness of the thigh or leg caused
by an obstruction in the venous system of various etiologies. Usually it is one
of many long-term consequences after deep vein thrombosis (DVT) of the lower
extremities. Post-thrombotic changes in the deep venous system can restrict
blood flow back to the heart. As a result, patients may experience leg and
thigh cramping and even pain, among other things. This is called venous
claudication. Symptoms usually resolve within 20 minutes of rest or after
lifting the leg.

Venous claudication is part of many venous symptoms and signs that can occur
after a DVT, often described as postthrombotic syndrome (PTS). In practice,
diagnosing PTS is done using scoring systems, such as the Villalta score,
Venous Clinical Severity Score (VCSS), or CEAP classification. These consist of
questions about patients' symptoms and criteria that can be observed on
physical examination. However, venous claudication is not an item in any of
these assessment tools, and to date none of the above classification systems
have been validated to measure PTS. In research, single venous symptoms and
signs are often measured as a derivative of the severity of PTS, such as leg
circumference, tingling, and pain. There is hardly any literature on methods to
objectively diagnose and assess VC, instead patients often state their symptoms
of cramping and pain experienced during exercise. For many patients, severe VC
is a serious disability leading to a significantly reduced quality of life and
significant socio-economic costs.

Patients who choose treatment are referred to a dermatologist or vascular
surgeon, who evaluates the degree of PTS and the presence, type, location, and
extent of venous obstruction. While there is currently no objective method to
diagnose and score the severity of venous claudication or PTS, invasive
treatment may be considered in patients with severe symptoms. In these
patients, a stent is placed to reconstruct the blocked arteries. The goal is to
establish adequate drainage of blood from the leg through the recanalized
segment. That reduces venous pressure and volume, which in turn should improve
symptoms. The success of this procedure is often judged by the patency of the
stents and the improvement in the patient's symptoms and quality of life. Up to
83% of patients report an improvement in VC after stent placement.

On the other hand, there is an overwhelming amount of data on treadmill testing
for assessing the severity of claudication caused by obstruction in the
arterial system. This treadmill test is fully standardized and can be used both
to diagnose arterial claudication and to assess the effect of treatment. For
venous claudication, this test is not used in current practice and only a few
studies have assessed the prevalence of PTS and VC using a treadmill test. Only
one study assessed whether placing a postthrombotic iliofemoral obstruction
reduced venous hypertension while using treadmill stress testing in combination
with invasive pressure measurements.

The goal of our study is to evaluate if it is feasible to incorporate a
standardized treadmill test into the workup of a patient with an iliofemoral
venous obstruction, who is planned for venous stenting, before and after the
procedure. We want to investigate if we are able to record the occurrence of VC
during the test as well as changes in distance and time without symptoms, after
stent placement. We will add leg circumference, PTS, VAS and QOL
questionnaires, as these are standard of care in our centre. We intend to
perform a larger study depending on the outcomes of this pilot study. Results
can be used for a better understanding of VC in relation to symptom severity,
to hopefully quantify the degree of VC, and to objectively measure the effect
of endovascular stenting.

This will be a single center pilot study as there is little literature on the
feasibility of treadmill testing to assess venous claudication. We also plan to
conduct a larger study, depending on the results of this pilot study. We expect
the total duration of the study to be 6 months, including inclusion and testing
before and after the intervention.

Patients will perform a treadmill exercise test. The treadmill test is
standardized and will have pre-set of the speed (3.2km/h) and inclination of 0%
at the beginning according to the protocol based on the study of Kurstjens et
al. Each 2 minutes, the inclination is increased by 2%. Participants are asked
to walk on a treadmill until they experience recognizable symptoms in their
affected leg such as tightness, pain, fatigue, heaviness, cramps or stiffness.

The only disadvantageof during study is that we will continue with the
treadmill test until participants develop complaints that may affect them.
However, if serious complaints occur, we will stop the test. In addition, these
symptoms are no different from those they may already experience during their
normal physical activity. In addition, we expect that patients will come to
Erasmus MC twice for the examination for an estimated time of 1.5 hours per
visit.