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

Sponsor

Ottawa Hospital Research Institute (Other)

Overall Status

Completed

CT.gov ID

NCT02297373

Collaborator

(none)

747

Enrollment

Locations

49.5

Actual Duration (Months)

Patients Per Site

1.7

Patients Per Site Per Month

Study Details

Study Description

Brief Summary

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.

Condition or Disease	Intervention/Treatment	Phase
Thromboembolic Disease Recurrent Deep Vein Thrombosis Pulmonary Embolism Venous Thromboembolism Recurrent Thromboembolic Disease

Detailed Description

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).

Study Design

Study Type:

Observational

Actual Enrollment :

747 participants

Observational Model:

Cohort

Time Perspective:

Prospective

Official Title:

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

Actual Study Start Date :

Nov 19, 2014

Actual Primary Completion Date :

Jan 3, 2019

Actual Study Completion Date :

Jan 3, 2019

Outcome Measures

Primary Outcome Measures

Validation of the Wells DVT clinical decision rule [3 years]
The rate of confirmed recurrent events using the Wells DVT clinical decision rule (CDR) will be analyzed for patients with a clinically suspected recurrent Venous Thromboembolism (VTE).
Validation of the Wells PE clinical decision rule [3 years]
The rate of confirmed recurrent events using the Wells PE CDR will be analyzed for patients with a clinically suspected recurrent Venous Thromboembolism (VTE).
Validation of the Geneva PE clinical decision rule [3 years]
The rate of confirmed recurrent events using the Geneva PE CDR will be analyzed for patients with a clinically suspected recurrent Venous Thromboembolism (VTE).

Secondary Outcome Measures

Clinical decision rule for suspected VTE in patients with a history of VTE [3 years]
A new CDR will be derived specific to patients with a history of VTE. This CDR will require assessment whether it would improve risk stratification as compared with the existing CDRs.
Accuracy of current D-dimer testing methods [3 years]
The rate of confirmed events using the current D-dimer cut-offs. Testing methods will be evaluated in patients with suspected recurrent VTE.
Rate of confirmed events using current Wells DVT/Wells PE/Geneva PE in participants on anticoagulant therapy [3 years]
The rate of confirmed events using Wells DVT/Wells PE/Geneva PE in patients currently being treated with anticoagulant therapy at the time of suspected recurrent VTE will be evaluated.

Eligibility Criteria

Criteria

Ages Eligible for Study:

18 Years and Older

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

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

Contacts and Locations

Locations

	Site	City	State	Country	Postal Code
1	Nova Scotia Health Authority	Halifax	Nova Scotia	Canada	B3H 1V7
2	Hamilton Health Sciences Centre	Hamilton	Ontario	Canada	L8L 2X2
3	Lawson Health Research Institute	London	Ontario	Canada	N6G 4A5
4	The Ottawa Hospital	Ottawa	Ontario	Canada	K1H 8L6
5	Hopital Montfort	Ottawa	Ontario	Canada	K1K 0T2
6	Humber River Hospital	Toronto	Ontario	Canada	M3M 0B2
7	Sir Mortimer B. Davis Jewish General Hospital	Montreal	Quebec	Canada	H3T 1E2
8	Leiden University Medical Centre	Leiden		Netherlands
9	Geneva University Hospital	Geneva		Switzerland