The purpose of this study is to determine if the use of image-guided, endovascular therapy (EVT) is an effective strategy with which to reduce Post Thrombotic Syndrome (PTS) disease severity and improve quality of life in patients with established disabling iliac-obstructive post thrombotic syndrome (DIO-PTS).



Eligible Ages
Over 18 Years
Eligible Genders
Accepts Healthy Volunteers

Inclusion Criteria

  1. Disabling (moderate-to-severe) PTS, defined by a) presence of chronic venous disease > 3 months duration in a leg with history of DVT; and b) either a Venous Clinical Severity Score (VCSS) > 8 or a Villalta PTS Scale score > 10 or an open venous ulcer); and
  2. Ipsilateral iliac vein obstruction documented within 3 months prior to screening by either:
  3. Occlusion or >50% stenosis of the iliac vein on venogram, CT venogram, MR venogram, or intravascular ultrasound (IVUS) or
  4. Air plethysmography showing deep venous obstruction of the ipsilateral leg (reduced venous outflow fraction), and ultrasound showing echogenic material in the ipsilateral iliac vein and non-phasic continuous Doppler flow in the ipsilateral common femoral vein (CFV) in the presence of normal phasic Doppler flow in the contralateral CFV.

Exclusion Criteria

  1. Age less than 18 years
  2. 2. Acute ipsilateral proximal DVT episode within the last 3 months, or acute contralateral DVT for which thrombolytic therapy is planned
  3. Lack of suitable inflow into the ipsilateral common femoral vein per the treating physician
  4. Documented obstruction (occlusion or > 50% diameter stenosis) of an IVC filter
  5. Chronic arterial limb ischemia (ankle-brachial index < 0.5)
  6. Presence of open venous ulcer > 50 cm2 area, or suspicion for active ulcer infection in the ipsilateral leg
  7. Inability to tolerate endovascular procedure due to acute illness, or general health
  8. Severe allergy to iodinated contrast refractory to steroid premedication
  9. Known allergy to stent or catheter components
  10. Hemoglobin < 8.0 g/dl, uncorrectable INR > 3.5, or platelet count < 50,000/ml
  11. Severe renal impairment (estimated GFR < 30 ml/min)
  12. Disseminated intravascular coagulation or other major bleeding diathesis
  13. Pregnancy (positive pregnancy test)
  14. Life-expectancy < 6 months or chronically non-ambulatory for reasons other than PTS
  15. Inability to provide informed consent or to comply with study assessments Note - patients who initially meet an exclusion criterion can be re-screened at a later date, and may be enrolled if all eligibility criteria are met at that time.

Study Design

Study Type
Intervention Model
Parallel Assignment
Intervention Model Description
This is an NIH-funded, Phase III, multicenter, randomized, open-label, assessor-blinded, parallel two-arm, controlled clinical trial.
Primary Purpose
Single (Outcomes Assessor)
Masking Description
Clinical assessments for PTS will be obtained at baseline (pre-randomization) and at the 6, 12, 18 and 24-month follow-up visits. Examining clinicians will complete PTS training to ensure accuracy across all Clinical Centers. The examiners for PTS must be blinded to the subjects' treatment allocation. Subjects will be reminded not reveal to clinic staff which therapy they received (EVT or No-EVT). Subjects should be examined in the afternoon (the later the better) to allow the symptoms and signs of PTS to manifest. The assessment is performed as follows: The subject should be asked to rate the 5 symptoms on the Villalta PTS scale for each leg, record his/her ratings on the CRF. The subject's legs should be unclothed and he/she should be seated facing the blinded clinician (nurse or physician).The 5 signs of PTS and VCSS measures will be recorded by the blinded clinician. Leg ulcers (if present) will be assessed and measured.

Arm Groups

ArmDescriptionAssigned Intervention
Endovascular Therapy - Intervention
All subjects (EVT and No-EVT Arms) will receive optimal PTS care. At each Clinical Center, this will be supervised by a physician experienced in managing PTS. Subjects randomized to EVT will receive the following: imaging-guided iliac vein stent placement, and endovenous ablation of refluxing saphenous vein(s), if the patient has truncal reflux and is still symptomatic. optimal PTS therapy: medical and compression, lifestyle interventions and venous ulcer care
  • Device: Stents
    US-guided puncture of vein, fluoroscopic monitoring of catheter/guidewire manipulations, baseline venogram of CFV through infrarenal IVC. Iliac vein should be pre-dilated to at least 12 mm. Bare, self-expanding stents made of elgiloy or nitinol legally marketed in the US for any indication and that are at least 12 mm in diameter should be used to recanalize the entire diseased segment of vein. The use of devices > 14 mm is highly recommended for the iliac vein and dilated to at least 14 mm, unless compelling patient factors dictates dilatation to a smaller diameter. Balloon angioplasty of inflow veins. After successful iliac vein recanalization, patients who continue to be symptomatic beyond 2 weeks follow-up and who have valvular reflux in GSV, accessory GSV, anterolateral thigh circumflex, and/or SSV should be offered endovenous ablation. Any FDA-approved method may be used including radiofrequency or laser ablation, sclerotherapy or pharmacomechanical ablation.
No Intervention
Non-Endovascular Therapy - Control
All subjects will receive optimal PTS care as noted above.

Recruiting Locations

University of Maryland
Baltimore, Maryland 21201
Kimberlly Nordstrom

More Details

Washington University School of Medicine

Study Contact

Angela Oliver, RN, BSN, MS

Detailed Description

The rationale for performing the C-TRACT Trial is based upon:

1. the debilitating life impact of DIO-PTS upon patients, as cited in the U.S. Surgeon General's 2008 Call to Action on DVT (95);

2. the inability of existing therapies to prevent or alleviate most cases of DIO-PTS;

3. the role of iliac vein obstruction and saphenous reflux in causing the severe manifestations of DIO-PTS;

4. the ability of stent placement and endovenous ablation to eliminate obstruction and reflux, respectively, to reduce PTS severity, and to improve QOL in preliminary studies;

5. the risks, costs, and uncertainties of this novel but invasive strategy;

6. the lack of consensus on whether EVT should be used for DIO-PTS;

7. the motivation of our established investigator team to answer this critical clinical question.

We will determine if EVT should be routinely used to treat DIO-PTS. If so, this finding will fundamentally change DIO-PTS practice towards more frequent use of EVT. If EVT proves ineffective or unsafe, this finding will reduce or eliminate the use of potentially risky and expensive procedures.

374 subjects with established DIO-PTS will be randomized in a 1:1 ratio to either EVT or No-EVT treatment groups. All participants will receive standard PTS therapy. Subjects will be enrolled over approximately 36 months in 20-40 U.S. Clinical Centers, and followed for 24 months. The study will take approximately 6 years to complete.


Study information shown on this site is derived from ClinicalTrials.gov (a public registry operated by the National Institutes of Health). The listing of studies provided is not certain to be all studies for which you might be eligible. Furthermore, study eligibility requirements can be difficult to understand and may change over time, so it is wise to speak with your medical care provider and individual research study teams when making decisions related to participation.