Contemporary Endovascular Therapies in Treatment of Acute Iliofemoral Deep Vein Thrombosis (CLEAR-DVT)

  • days left to enroll
  • participants needed
  • sponsor
    Guy's and St Thomas' NHS Foundation Trust
Updated on 14 February 2022
deep vein thrombosis
blood clot
venous thrombosis
deep venous thrombosis of lower extremity
post thrombotic syndrome


The goal of this initial proof of principle single arm cohort trial is to determine if contemporary endovascular venous intervention, compared with a 1:1 propensity-matched medical therapy arm of the ATTRACT trial, significantly reduces the 2-year occurrence of Post Thrombotic Syndrome (PTS) in subjects with symptomatic proximal Deep Vein Thrombosis (DVT).


A single arm cohort will serve as a proof of principle study, and be the foundation for a larger subsequent prospective, Randomised Clinical Trial (RCT). The aim of this initial single arm cohort is to both validate that contemporary catheter directed therapy performed by experienced operators has significant efficacy and safety at 10 days, 30 days, 6 months, 12 months, and 2 years (details below). If a strong signal of efficacy and safety is found in the initial single arm cohort at 30 days and 6 months, this will provide objective evidence to move forward with a larger multicentre, prospective, RCT.

If the results of the initial single arm proof of principle cohort do not show efficacy, or there is a safety issue, a larger prospective, RCT will not be performed.

Condition Thrombolysis, Deep Vein Thrombosis
Treatment Contemporary endovascular venous intervention by Zelante pharmacomechanical thrombolysis
Clinical Study IdentifierNCT03901872
SponsorGuy's and St Thomas' NHS Foundation Trust
Last Modified on14 February 2022


Yes No Not Sure

Inclusion Criteria

Patient age 16 years to 75 years
Onset of acute DVT symptoms of 14 days or less in the study limb
DVT located in the common and/or external iliac, or common femoral vein
Consent to participate in this research study and be willing to commit to study requirements including completion of questionnaires and follow-up visits

Exclusion Criteria

In the index leg: established PTS, or previous symptomatic DVT within the last 2 years
In the contralateral (non-index) leg: symptomatic acute DVT a) involving the iliac and/or common femoral vein; or b) for which thrombolysis is planned as part of initial therapy
Limb-threatening circulatory compromise
Pulmonary embolism defined as either massive (Systolic blood pressure < 90 mmHg and/or patient on IV vasoactive medication to support blood pressure), or intermediate high risk pulmonary embolism (PE), as defined by the European Society Guideline on management of PE. Low risk PE and/or intermediate low risk PE can be enrolled
Inability to tolerate contemporary venous intervention procedure due to severe dyspnea or acute systemic illness
Allergy, hypersensitivity, or thrombocytopenia from heparin, Recombinant tissue plasminogen activator (rtPA), or iodinated contrast, except for mild-moderate contrast allergies for which steroid pre-medication can be used
Haemoglobin < 9.0 mg/dl, INR > 1.6 before starting anticoagulation, or platelets < 100,000/ml. Moderate renal impairment in diabetic patients (estimated glomerular filtration rate < 60 ml/min) or severe renal impairment in non-diabetic patients (estimated glomerular filtration rate < 30 ml/min)
Active bleeding, recent (< 3 mo) GI bleeding, severe liver dysfunction, bleeding diathesis
Recent (< 3 mo) internal eye surgery or haemorrhagic retinopathy; recent (< 10 days) major surgery, cataract surgery, trauma, cardiopulmonary resuscitation, obstetrical delivery, or other invasive procedure
History of stroke or intracranial/intraspinal bleed, tumor, vascular malformation, aneurysm
Active cancer (metastatic, progressive, or treated within the last 6 months). Exception: patients with non-melanoma primary skin cancers are eligible to participate in the study
Severe hypertension on repeated readings (systolic blood pressure > 180 mmHg or diastolic blood pressure > 105 mmHg). This can be treated, and blood pressure must be stable before venous access is obtained (systolic blood pressure <140 mmHg)
Pregnant (positive pregnancy test, women of childbearing potential must be tested)
Recently (< 1 mo) had thrombolysis or is participating in another investigational device or drug study that may convolute study results
Life expectancy < 2 years or chronic non-ambulatory status
Inability to provide informed consent or to comply with study assessments (e.g. due to cognitive impairment or geographic distance)
Inferior vena cava (IVC) thrombus. Significant thrombus of the IVC, by definition, thrombus extending more than one centimeter above the IVC - common iliac vein confluence will be a cause for exclusion
Inability to obtain access of the enrolled ipsilateral popliteal vein using ultrasound guided micro-puncture technique
History of, or active heparin induced thrombocytopenia (HIT)
Clear my responses

How to participate?

Step 1 Connect with a study center
What happens next?
  • You can expect the study team to contact you via email or phone in the next few days.
  • Sign up as volunteer  to help accelerate the development of new treatments and to get notified about similar trials.

You are contacting

Investigator Avatar

Primary Contact


Additional screening procedures may be conducted by the study team before you can be confirmed eligible to participate.

Learn more

If you are confirmed eligible after full screening, you will be required to understand and sign the informed consent if you decide to enroll in the study. Once enrolled you may be asked to make scheduled visits over a period of time.

Learn more

Complete your scheduled study participation activities and then you are done. You may receive summary of study results if provided by the sponsor.

Learn more

Similar trials to consider


Browse trials for

Not finding what you're looking for?

Every year hundreds of thousands of volunteers step forward to participate in research. Sign up as a volunteer and receive email notifications when clinical trials are posted in the medical category of interest to you.

Sign up as volunteer

user name

Added by • 



Reply by • Private

Lorem ipsum dolor sit amet consectetur, adipisicing elit. Ipsa vel nobis alias. Quae eveniet velit voluptate quo doloribus maxime et dicta in sequi, corporis quod. Ea, dolor eius? Dolore, vel!

  The passcode will expire in None.

No annotations made yet

Add a private note
  • abc Select a piece of text from the left.
  • Add notes visible only to you.
  • Send it to people through a passcode protected link.
Add a private note