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

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Know the risks and potential benefits of clinical studies and talk to your health care provider before participating. Read our disclaimer for details. Identifier: NCT03901872
Recruitment Status : Recruiting
First Posted : April 3, 2019
Last Update Posted : August 2, 2019
Information provided by (Responsible Party):
Guy's and St Thomas' NHS Foundation Trust

Brief Summary:
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).

Condition or disease Intervention/treatment
Thrombolysis Deep Vein Thrombosis Device: Contemporary endovascular venous intervention by Zelante pharmacomechanical thrombolysis

Detailed Description:

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.

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Study Type : Observational
Estimated Enrollment : 65 participants
Observational Model: Cohort
Time Perspective: Prospective
Official Title: Contemporary Endovascular Therapies in Treatment of Acute Iliofemoral Deep Vein Thrombosis A Prospective, Multicentre Cohort Trial A Physician Initiated Research Study Request
Actual Study Start Date : March 29, 2019
Estimated Primary Completion Date : February 2023
Estimated Study Completion Date : February 2023

Group/Cohort Intervention/treatment
Acute Iliofemoral DVT
Suitable patients would be invited to take part in this trial as part of standard of care.
Device: Contemporary endovascular venous intervention by Zelante pharmacomechanical thrombolysis
All patients will undergo ultrasound guided micro puncture venous access of the enrolled ipsilateral lower extremity popliteal vein followed by a diagnostic venogram to define thrombus burden and anatomic extent of DVT. Prior to and every 30 minutes during the endovascular procedure, an activated clotting time (ACT) will be obtained. Intravenous unfractionated heparin will be administered to keep the ACT between 250 - 300. A Zelante catheter will be utilised to perform pharmacomechanical thrombolysis of the enrolled lower extremity. If there is involvement of the popliteal and/or femoral vein, pharmacomechanical thrombolysis should also be performed of these veins. Venous stenting may be implemented to address areas of residual venous stenosis or outflow obstruction following pharmacomechanical thrombolysis. Stent placement in the common iliac, external iliac, and common femoral vein are routinely done to address inflow or outflow issues after pharmacomechanical thrombolysis.

Primary Outcome Measures :
  1. Rate of Post thrombotic Syndrome at 2 years [ Time Frame: 2 years ]

Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.

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Ages Eligible for Study:   16 Years to 75 Years   (Child, Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Sampling Method:   Non-Probability Sample
Study Population
All acute DVT patients will be screened for entry into the trial

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).

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT03901872

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Contact: Audrey Hau 02071887188 ext 53821
Contact: Stephen Black 02071887188 ext 53821

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United Kingdom
Guy's & St Thomas' NHS Foundation Trust Recruiting
London, United Kingdom, SE1 7EH
Contact: Audrey Hau    02071887188 ext 53821   
Sponsors and Collaborators
Guy's and St Thomas' NHS Foundation Trust
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Responsible Party: Guy's and St Thomas' NHS Foundation Trust Identifier: NCT03901872    
Other Study ID Numbers: IRAS 254427
First Posted: April 3, 2019    Key Record Dates
Last Update Posted: August 2, 2019
Last Verified: April 2019
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: Undecided

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: Yes
Product Manufactured in and Exported from the U.S.: No
Additional relevant MeSH terms:
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Venous Thrombosis
Embolism and Thrombosis
Vascular Diseases
Cardiovascular Diseases