Trial Review

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Trial registered on ANZCTR


Registration number
ACTRN12609000359235
Ethics application status
Approved
Date submitted
6/05/2009
Date registered
26/05/2009
Date last updated
5/06/2018
Type of registration
Retrospectively registered

Titles & IDs
Public title
3-point compression ultrasonography performed by consultant emergency physicians in the emergency department for the diagnosis of proximal lower extremity deep venous thrombosis
Scientific title
The utility of 3-point compression ultrasonography performed by consultant emergency physicians for the diagnosis of proximal lower-extremity deep venous thrombosis in symptomatic patients presenting to the emergency department, compared with reference-standard formal full-leg duplex ultrasonography performed in the radiology department
Secondary ID [1] 855 0
Nil
Universal Trial Number (UTN)
Trial acronym
Nil
Linked study record

Health condition
Health condition(s) or problem(s) studied:
The diagnosis of lower-extremity deep venous thrombosis in the emergency department 4725 0
Condition category
Condition code
Cardiovascular 237051 237051 0 0
Other cardiovascular diseases

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
3-point compression ultrasonography for the diagnosis of proximal lower-extremity deep venous thrombosis performed by emergency physicians in the emergency department.

This ultrasonographic examination only involves evaluation of the compressibility of specific veins at three sites: the common femoral vein just below the inguinal ligament, the great saphenous vein approximately 3 - 4cm distal to the saphenofemoral junction, and the popliteal vein in the popliteal fossa.

It is a brief and simple examination which we expect to take less than 10 minutes to perform.

Those performing the ultrasonography will be consultant emergency physicians: no doctor or healthcare worker of a lesser experience level will participate.
Intervention code [1] 4496 0
Diagnosis / Prognosis
Comparator / control treatment
Reference-standard formal full-leg duplex ultrasonography for the diagnosis of lower extremity deep venous thrombosis performed in the radiology department.

This reference-standard ultrasonographic examination involves an interrogation of all the deep veins in the symptomatic limb, with Doppler flow measurements and other augmentation techniques.

It is performed in the Radiology Department by an ultrasonographer technician, and then interpreted by a Radiologist.

It is currently considered the practical 'gold-standard' in diagnosing lower-extremity deep venous thrombosis (DVT).

The duration of the actual examination itself can extend up to 30 - 40 minutes.

Patients will first have the 3-point compression ultrasonographic index test performed in the Emergency Department by the Consultant Emergency Physician, and then have the reference-standard formal full-leg duplex ultrasonography performed in the Radiology Department.

The referral for the Radiology Department ultrasonography will be made upon patient enrolment, and will occur as soon as possible after the Emergency Department ultrasonographic examination: the time between the examinations will vary, because the Radiology Department normally can only perform this type of ultrasonographic examination during working hours.
Control group
Active

Outcomes
Primary outcome [1] 5891 0
Primary Outcome 1: sensitivity and specificity of 3-point compression ultrasonography for the diagnosis of proximal lower-extremity deep venous thrombosis when compared with reference-standard formal full-leg duplex ultrasonography.

The results of the 3-point compression ultrasonographic examinations will be collected through a Standard Data Collection Form and subsequently classified using a standardised protocol, as being either: positive, negative, or equivocal.

A positive examination will be one in which there is any evidence of any thrombus in any target vein. A negative examination will be one in which there is no evidence of any thrombus in any target vein. An equivocal examination will be one which is indeterminate: for example, if a particular vein cannot be confidently identified by the participating Consultant Emergency Physician.

In the event of a positive examination, participating Consultant Emergency Physicians will also record where any thrombus was identified.

In the event of an equivocal examination, the Consultant Emergency Physicians will record the reasons why they failed to complete an unequivocal examination.

These results will then be compared to the results of the reference-standard formal full-leg duplex ultrasonography performed in the Radiology Department, which will be taken from the Hospital electronic medical records system and then subjected to a similar standardised classification system.

Appropriate statistical modeling will be used to determine the sensitivity, specificity, and overall diagnostic accuracy of the index test compared to the reference-standard test.
Timepoint [1] 5891 0
within 48 hours of patient enrolment.
Primary outcome [2] 5892 0
time taken to perform examination, and rapidity of diagnosis, with 3-point compression ultrasonography compared with reference-standard formal full-leg duplex ultrasonography.
Timepoint [2] 5892 0
within 48 hours of patient enrolment.
Primary outcome [3] 5893 0
learning curve experienced by consultant emergency physicians in performing the 3-point compression ultrasonography for the diagnosis of proximal lower-extremity deep venous thrombosis, represented by chronological location of false-positives, -negatives, and equivocal results in the context of their accumulating experience as they perform more examinations in the study.
Timepoint [3] 5893 0
the duration of the study, 15 - 24 months.

This outcome will be assessed once the study has been completed. This will be possible as the Standard Data Collection Forms used to document the results of each ultrasonographic examination performed by each individual participating Consultant Emergency Physician will record adequate information to allow each single examination to be located in their individual series chronologically, and for the results of these examinations to be known.
Secondary outcome [1] 241924 0
rate and cause of equivocal results returned by 3-point compression ultrasonography performed by consultant emergency physicians.

As previously outlined for Primary Outcome 1, the results of both the index and reference tests will be adequately recorded and will then be subjected to standardised classification systems.

3-point compression ultrasonographic examinations will be considered equivocal if: (a) any target vein could not be identified, OR (b) the clinician remains unsure as to whether thrombus was present at any target location.

The Standard Data Collection Forms will ensure adequate information is collected to enable this sub-classification to occur and for the cause of each 'equivocal' examination to be known.
Timepoint [1] 241924 0
within 48 hours of patient enrolment.
Secondary outcome [2] 241925 0
statistical analysis of the changes in time taken by individual consultant emergency physicians to complete each 3-point compression ultrasonographic examination, in the context of their accumulating experience.
Timepoint [2] 241925 0
the duration of the study, 15 - 24 months.

This will be assessed once the study has been completed. The Standard Data Collection Forms will ensure that all the data necessary to perform this analysis will be collected.
Secondary outcome [3] 241926 0
anecdotal qualitative data gleaned from the experiences of the experienced consultant emergency physician through the Initial Training Period aspect of this study.
Timepoint [3] 241926 0
Initial Training Period of the study, 1 - 4 months.

This anecdotal qualitative outcome will be assessed following the completion of the 'Training Phase' of the study, once all participating Consultant Emergency Physicians have completed three supervised 3-point compression ultrasonographic examinations on patients fitting the selection criteria.

This will represent approximately 30 examinations in total, as approximately 10 Consultant Emergency Physicians are envisaged to take part.

The supervisor, AProf. Robert Dunn, will record this anecdotal qualitative data regarding the performance and learning-curve of the training participating Consultant Emergency Physicians on the Standard Data Collection Form he will use to first examine the patient with the 3-point compression technique, before continuing to supervise the training participating Consultant Emergency Physicians.

AProf. Dunn is highly experienced in the use of ultrasonography to diagnose DVT with a 3-point technique.
Secondary outcome [4] 241927 0
statistical analysis of the rate at which consultant emergency physicians are able to correctly predict that their ultrasonographic examination shall return equivocal results.

Participating Consultant Emergency Physicians will, before beginning each ultrasonographic examination in the trial, be asked to predict whether the examination will be equivocal or unequivocal.

Their predictions will be compared to their actual results, as recorded on the Standard Data Collection Forms, and as classified via the standardised classification protocol.
Timepoint [4] 241927 0
the duration of the study, 15 - 24 months.

This outcome will be assessed once the study has been completed.

The relevant data will be recorded on the Standard Data Collection Form for each 3-point compression ultrasonographic examination, and so this post-study assessment will be possible.
Secondary outcome [5] 241928 0
statistical analysis of the association between the reported patient factors of obesity, degree of inaccessibility of the sites required for the 3-point compression ultrasonographic examination, history of vascular surgery on the symptomatic limb and history of deep venous thrombosis as reported by the patient, and equivocal results returned by the consultant emergency physician-performed ultrasonographic examinations. The existence of these patient factors will be recorded on the Standard Data Collection Forms: patient-reported values for height, weight, history of vascular surgery and history of deep venous thrombosis will be recorded, and their ability to move their leg to accommodate an ultrasonographic examination will be assessed and recorded by the participating emergency-physician ultrasonographer. These patient factors will then be correlated with the results of the relevant examinations, using appropriate statistical methods.
Timepoint [5] 241928 0
the duration of the study, 15 - 24 months.

This outcome will be assessed once the study has been completed.
Secondary outcome [6] 241929 0
direct measurement of the percentage of reference-standard formal full-leg duplex ultrasonographic examinations which detect isolated proximal great saphenous vein (GSV) thrombosis in our patient population.
Timepoint [6] 241929 0
the duration of the study, 15 - 24 months.

This will be assessed once the study has been completed.

The relevant data will be collected for each 3-point compression ultrasonographic examination and reference-standard examination, to enable this post-study assessment to be performed.

Eligibility
Key inclusion criteria
Patients presenting to the emergency department with clinical indications of deep venous thrombosis, as determined by their treating emergency department doctor, who are 18 years of age, or older
Minimum age
18 Years
Maximum age
No limit
Sex
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
Lower extremity ultrasonography (US) of the symptomatic limb within the previous 48 hours;

The presence of an indwelling femoral vascular catheter or dialysis vascular shunt in the symptomatic limb;

An above knee-amputation of the symptomatic limb;

The complete inability to access any of the 3 landmarks on the symptomatic limb that are required for the 3-point compression ultrasonographic examination. The general areas in question are the anteromedial aspect of the thigh inferior to the inguinal ligament, and the popliteal fossa;

An open wound involving any of the 3 landmarks on the symptomatic limb that are required for the 3-point compression ultrasonographic examination;

Allergy to the gel used in the ultrasonographic examination; though this is extremely rare, it has been reported and must be considered.

Study design
Purpose of the study
Diagnosis
Allocation to intervention
Non-randomised trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Allocation is not concealed
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Not applicable (interventional study)
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?



Intervention assignment
Crossover
Other design features
Nil
Phase
Not Applicable
Type of endpoint/s
Safety/efficacy
Statistical methods / analysis

Recruitment
Recruitment status
Stopped early
Data analysis
Reason for early stopping/withdrawal
Date of first participant enrolment
Anticipated
11/05/2009
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
300
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)

Funding & Sponsors
Funding source category [1] 4905 0
Hospital
Name [1] 4905 0
Royal Adelaide Hospital
Country [1] 4905 0
Australia
Funding source category [2] 4906 0
University
Name [2] 4906 0
The University of Adelaide
Country [2] 4906 0
Australia
Primary sponsor type
Individual
Name
AProf. Robert Dunn
Address
Robert Dunn
Department of Emergency Medicine
Royal Adelaide Hospital
North Terrace
Adelaide
South Australia 5000
Country
Australia
Secondary sponsor category [1] 4436 0
Individual
Name [1] 4436 0
Thomas Crowhurst
Address [1] 4436 0
Thomas Crowhurst
Department of Emergency Medicine
Royal Adelaide Hospital
North Terrace
Adelaide
South Australia 5000
Country [1] 4436 0
Australia

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 6970 0
Royal Adelaide Hospital Research Ethics Committee
Ethics committee address [1] 6970 0
Royal Adelaide Hospital (RAH) Research Ethics Committee
Level 3, Hanson Institute
Royal Adelaide Hospital
North Terrace
Adelaide
South Australia 5000
Ethics committee country [1] 6970 0
Australia
Date submitted for ethics approval [1] 6970 0
Approval date [1] 6970 0
17/04/2009
Ethics approval number [1] 6970 0
090406

Summary
Brief summary
This study aims to evaluate the overall usefulness of 3-point compression ultrasonosgraphy performed by emergency physicians in the emergency department for the diagnosis of proximal lower-extremity deep venous thrombosis.

In order to be useful, the examination should be accurate, fast, technically adequate and easy to learn. Therefore, this study will examine the accuracy, rapidity and technical adequacy of the examination, as well as the learning curve emergency physicians experiencing with the examination.

We hypothesise that the examination will be useful.
Trial website
Not applicable
Trial related presentations / publications
Not applicable
Public notes

Contacts
Principal investigator
Name 29574 0
Mr Thomas Crowhurst
Address 29574 0
Thomas Crowhurst Department of Emergency Medicine Royal Adelaide Hospital North Terrace Adelaide South Australia 5000
Country 29574 0
Australia
Phone 29574 0
+61 439 810 678
Fax 29574 0
Email 29574 0
[email protected]
Contact person for public queries
Name 12821 0
Mr Thomas Crowhurst
Address 12821 0
Thomas Crowhurst
Department of Emergency Medicine
Royal Adelaide Hospital
North Terrace
Adelaide
South Australia 5000
Country 12821 0
Australia
Phone 12821 0
+61 439 810 678
Fax 12821 0
Email 12821 0
[email protected]
Contact person for scientific queries
Name 3749 0
Mr Thomas Crowhurst
Address 3749 0
Thomas Crowhurst
Department of Emergency Medicine
Royal Adelaide Hospital
North Terrace
Adelaide
South Australia 5000
Country 3749 0
Australia
Phone 3749 0
+61 439 810 678
Fax 3749 0
Email 3749 0
[email protected]

No information has been provided regarding IPD availability


What supporting documents are/will be available?

No Supporting Document Provided



Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
No additional documents have been identified.