Skip to main content
OpenTrials
Completed

NCT Number: NCT02297373

Clinical Predictors for Venous Thromboembolism in Patients With a History of Thrombosis (PREDICTORS)

Patients with a history of blood clots are at risk of developing additional clots in the future. Doctors use a tool called a clinical decision rule to tell them how likely it is that a patient has a blood clot and if they should have further testing to look for the clot. This tool may cause doctors to over-diagnosis a recurrent clot because the symptoms may be left over from the previous clot. Correctly diagnosing a recurrent blood clot is very important since there are risks associated with both over-diagnosis and under-diagnosis. If a recurrent blood clot is missed (under-diagnosis) the patient is at risk of death from a clot in the lungs. If blood thinners are prescribed when they are not needed (over-diagnosis), the patient may have to take blood thinners for their lifetime and risk having serious bleeding.

Completed

Looking for future studies?

Notify Me

Key information

Conditions

Thromboembolic Disease Recurrent Cardiovascular Diseases Deep Vein Thrombosis Embolism Embolism and Thrombosis Lung Diseases Pulmonary Embolism Recurrent Thromboembolic Disease Respiratory Tract Diseases Thromboembolism Thrombosis Vascular Diseases Venous Thromboembolism Venous Thrombosis

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

Nova Scotia Health Authority, Halifax, Nova Scotia, Canada

Loading trial locations.

About this study

Several tools have been developed to standardize the diagnostic management of a suspected first blood clot. One of these tools is the use of a clinical decision rule. Clinical decision rules have been designed to help clinicians make diagnostic and therapeutic decisions at the bedside. A score is computed on the presence of some criteria from the patient's medical history, clinical signs and symptoms. The score provides the probability of a blood clot. The rules can be used in combinations with a simple blood test - called D-dimer - to identify patients at low risk who don't require diagnostic imaging testing. Benefits include reduced costs, length in hospital and radiation exposure.

Patients with prior blood clots have been shown to be less likely to benefit from the non-invasive testing. Therefore, they often need to undergo imaging tests, which are frequently difficult to interpret in patients with prior blood clots since residual clots are often present and are difficult to distinguish from a recurrent clot.

The objective of this study is to try to prospectively assess the role of existing clinical decision rules in patients with prior blood clots, and to attempt to improve them in order to increase the yield of non-invasive testing and to reduce the risk of over-diagnosis with imaging tests.

With respect to this study, clots within the deep veins of the legs are called deep vein thrombosis (DVT), while clots in the lungs are called pulmonary embolism (PE).

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Outpatients with clinically suspected acute recurrent DVT or PE regardless of whether the previous event was a DVT or PE
  • Age ≥18 years old
  • Willing and able to give informed consent

Exclusion criteria

  • Life expectancy less than 3 months
  • Suspicion of upper extremity thrombosis or thrombosis at an unusual site (e.g. cerebral or abdominal venous thrombosis)
  • Previous VTE was distal DVT or subsegmental PE
  • Suspected recurrent VTE is asymptomatic
  • Previously enrolled in this study

Treatment and study plan

Primary outcomes

  1. Validation of the Wells DVT Clinical Decision Rule

    Time frame: Day 0 (at time of suspected recurrent DVT)

    The Wells DVT Clinical Decision Rule (CDR) assigns a score from -2 to +9 based on clinical variables (e.g., active cancer, limb swelling, localized tenderness, prior history of DVT, alternative diagnosis as likely or more likely than DVT). In this study, the 3-level Wells DVT CDR was applied prospectively at presentation (Day 0) to participants with suspected recurrent DVT, using data collected from patient history and physical examination. Scores classify patients into low (≤0), moderate (1-2), or high (≥3) probability of DVT. Higher scores indicate greater probability of recurrent DVT. The outcome measure was the rate of confirmed recurrent DVT events within each Wells category, confirmed by objective imaging and adjudicated by an independent committee.

  2. Validation of the Wells PE Clinical Decision Rule

    Time frame: Day 0 (at time of suspected recurrent PE)

    The 3-level Wells PE score (range 0-12.5) was calculated from history and exam at the index visit. Scores ≤4 = PE unlikely, >4 = PE likely. Higher scores indicate greater likelihood of PE. The outcome is the proportion with confirmed recurrent PE at the index diagnostic work-up, adjudicated by blinded review of imaging.

  3. Validation of the Geneva PE Clinical Decision Rule

    Time frame: Day 0 (at time of suspected recurrent PE)

    The revised Geneva score (range 0-22) was calculated from history and exam at the index visit. Scores 0-3 = low, 4-10 = intermediate, ≥11 = high probability. Higher scores indicate greater likelihood of PE. The outcome is the proportion with confirmed recurrent PE at the index diagnostic work-up, adjudicated by blinded review of imaging.

Secondary outcomes

  1. Accuracy of Current D-dimer Testing Methods

    Time frame: Day 0 (at time of suspected recurrent VTE)

    D-dimer testing at the index visit was performed using the institutional cut-off for positivity in place during the study period (2014-2019). Results were classified as positive or negative. The outcome is the proportion with confirmed recurrent VTE in each test category at the index diagnostic work-up, adjudicated by blinded review of imaging.

  2. Rate of Confirmed Events Using Current Wells DVT/Wells PE/Geneva PE in Participants on Anticoagulant Therapy

    Time frame: Day 0 (at time of suspected recurrent VTE)

    The Wells DVT, Wells PE, and Geneva PE scores were calculated at the index visit in participants on anticoagulation. Score ranges and cut-offs as per respective rules. The outcome is the proportion with confirmed recurrent VTE in each risk category at the index diagnostic work-up, adjudicated by blinded review of imaging.

  3. All-Cause Mortality Within 90 Days of Index Visit

    Time frame: From enrollment (Day 0) through Day 90 follow-up for those not diagnosed with a confirmed recurrent VTE at enrollment

    Number of participants who died from any cause from enrollment (Day 0) through Day 90 follow-up for those without confirmed recurrent VTE at enrollment.

Sponsors and collaborators

Lead sponsor

Ottawa Hospital Research Institute

Other

Registry information

Official study title

Clinical Predictors for Venous Thromboembolism in Patients With a History of Thrombosis

Acronym: PREDICTORS

Important dates

Study start
2014
Primary completion
2019
Study completion
2019
First posted
Nov 21, 2014
Registry last updated
Sep 5, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Related clinical trials

Published trials that share one or more normalized conditions with this study.