Isolated Distal DVTCALTHRONCT00816920
Natural History of Isolated Deep Vein Thrombosis of the Calf
An observational study of Isolated Distal DVT and Proximal DVT, run by IRCCS Azienda Ospedaliero-Universitaria di Bologna at 2 sites in Italy.
Trial summary
Whether isolated distal DVT (IDDVT), DVT confined to the calf, should be looked for and diagnosed to allow them to be treated with anticoagulants remains one of the still unsolved issues in vascular medicine, especially because of the insufficient data on clinical risks of untreated distal DVT. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Isolated Distal DVT, Proximal DVT, Pulmonary Embolism
- What is being tested?
- Ultrasound examination of leg veins
- How many people
- 500 participants
- Where
- 2 sitesItaly
- Study dates
- Sep 2005to Sep 2009
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: outpatients with suspected deep vein thrombosis (DVT) of a leg in whom a proximal DVT is excluded. The study is not funded. As a result, it will not be possible to enroll all consecutive eligible patients; rather patients will be included based on the availability of expert medical staff in the day of their presentation (in general the first patient of the day).
Who may be able to join
- suspected deep vein thrombosis of a leg
- intermediate/high pre-test clinical probability or high D-dimer levels
Who cannot join
- age < 18 years
- presence of proximal DVT
- suspected isolated iliac DVT
- symptoms/signs lasting from > 30 days
- presence of symptoms of pulmonary embolism
- pregnancy or puerperium
Show all 12Show fewer
- full dose treatment with heparin or derivatives from > 1 day
- presence of superficial vein thrombosis
- limited life expectancy (< 6 months)
- geographically inaccessible location
- inability or refusal to give consent
- participation in other clinical studies
Trial locations and contacts
2 sites in 1 country.
Italy2 sites
Angiology & Blood Coagulation, Policlinico S. Orsola-Malpighi
Bologna, 40138
Servizio di Fisiopatologia Vascoalre, Casa di Cura Villa Serena
Pescara, 65100
About this study
Official title: Diagnosis and Evolution of Isolated Deep Vein Thrombosis of the Calf in Symptomatic Outpatients. The Blind, Prospective "CALTHRO" Study.
Whether isolated distal DVT (IDDVT), DVT confined to the calf, should be looked for and diagnosed to allow them to be treated with anticoagulants remains one of the still unsolved issues in vascular medicine, especially because of the insufficient data on clinical risks of untreated distal DVT. Management studies have shown that it is safe to withhold anticoagulation in outpatients with suspected DVT if compression ultrasonography (CUS) limited to the proximal deep veins yields normal results on presentation and on repeated examination after 5 to 7 days. This strategy is based on the premise that IDDVT do not need to be diagnosed and treated, what is necessary when they extend involving the proximal veins. There is no general agreement, however, on the assumption that the non-extending IDDVT do not need to be diagnosed and treated, and many authors recommend to perform a single CUS examination extended to the distal deep veins. All the available studies have treated with anticoagulants the diagnosed IDDVT and no adequate information is available on the risk of IDDVT left untreated.
The present study, performed in outpatients with suspected leg DVT, aims at assessing the clinical consequences of IDDVT diagnosed (by a complete US investigation) but not treated because the results of this investigation remain blind to both the patient and the treating doctor, whereas the diagnostic-therapeutic procedure remains the usual one, based on CUS investigation limited to diagnose proximal DVT, to be repeated after 5-7 days (or earlier) to exclude an extension to proximal veins of an IDDVT potentially present.
Read the detailed description
Outpatients symptomatic for suspected DVT of a leg are examined by a vascular doctor according to standard procedure based on pre-test clinical probability (PTCP) assessment, D-dimer assay and a CUS limited to the proximal deep veins. Those in whom a proximal DVT is excluded and have intermediate/high PTCP or altered D-dimer level are eligible for the study. The included patients are immediately submitted to an extensive echo-color-Doppler examination of calf deep veins by a different vascular doctor and results are closed in an envelope that will be open after three months (or before if necessary). In the meantime, patients will follow the standard diagnostic procedure: they receive an appointment to come back in 5-7 days for a further CUS examination, or even before in case of worsening of symptoms/signs. All the included patients receive a telephone call after three months to exclude possible complications.
- Conditions
- Isolated Distal DVT, Proximal DVT, Pulmonary Embolism
- Being tested
- Ultrasound examination of leg veins
- Keywords
- distal DVT, calf DVT, DVT diagnosis, management of patients with suspected leg DVT
- Medical subject headings
- Pulmonary Embolism
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Ultrasound examination of leg veinsOther
Outpatients symptomatic for leg DVT follow the standard diagnostic procedure (ultrasound examination of proximal deep veins, pre-test clinical probability and D-dimer, and a second US after 5-7 days) to exclude proximal DVT; they also receive by another doctor a complete US examination of the deep leg veins to assess the presence of isolated calf DVT, the results of the latter examination are kept blind to the patient and to the treating doctor, and disclosed after three months
| Study group | Role | What they receive |
|---|---|---|
| 1 | Outpatients with suspected leg DVT after exclusion of proximal DVT Receives: Other: Ultrasound examination of leg veins |
What is being measured
The primary outcome is the main question the study is designed to answer.
Thrombotic complications (deep vein thrombosis and/or pulmonary embolism within three months from first examination
Measured: three months from first examination
Secondary outcomes (1)
other vascular complications; how many isolated distal DVT will be diagnosed
Measured: three months from first examination
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted5 Jan 2009 (estimated)
- Study startSep 2005
- Primary completionSep 2009
- Study completionSep 2009
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Isolated Distal DVTStudies of the same condition, open and under way.
- More trials run by IRCCS Azienda Ospedaliero-Universitaria di BolognaThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 500 participants (actual)
Sponsor and investigators
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Gualtiero Palareti, MD, Principal investigator, Azienda Ospedaliero-Universitaria di Bologna, Policlinico S. Orsola-Malpighi
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT00816920
- Sponsor's protocol ID
- 24/2001/O EM60/2007/O
- Acronym
- CALTHRO
- Status last verified
- Mar 2021
- First submitted
- 2 Jan 2009
- Last updated
- 22 Mar 2021
- Results posted
- No
- Data monitoring committee
- Yes
Study at a glance
From the registry record, last updated by the sponsor on 22 Mar 2021. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Diagnosis and Evolution of Isolated Deep Vein Thrombosis of the Calf in Symptomatic Outpatients. The Blind, Prospective "CALTHRO" Study.
- ClinicalTrials.gov ID
- NCT00816920
- Acronym / sponsor ID
- CALTHRO / 24/2001/O EM60/2007/O
- Conditions
- Isolated Distal DVT, Proximal DVT, Pulmonary Embolism
- Keywords
- distal DVT, calf DVT, DVT diagnosis, management of patients with suspected leg DVT
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 500 participants (actual)
- Lead sponsor
- IRCCS Azienda Ospedaliero-Universitaria di BolognaUniversity, hospital or other
- Study start
- Sep 2005
- Primary completion
- Sep 2009 (actual)
- Study completion
- Sep 2009 (actual)
- First posted
- 5 Jan 2009 (estimated)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Whether isolated distal DVT (IDDVT), DVT confined to the calf, should be looked for and diagnosed to allow them to be treated with anticoagulants remains one of the still unsolved issues in vascular medicine, especially because of the insufficient data on clinical risks of untreated distal DVT. Management studies have shown that it is safe to withhold anticoagulation in outpatients with suspected DVT if compression ultrasonography (CUS) limited to the proximal deep veins yields normal results on presentation and on repeated examination after 5 to 7 days. This strategy is based on the premise that IDDVT do not need to be diagnosed and treated, what is necessary when they extend involving the proximal veins. There is no general agreement, however, on the assumption that the non-extending IDDVT do not need to be diagnosed and treated, and many authors recommend to perform a single CUS examination extended to the distal deep veins. All the available studies have treated with anticoagulants the diagnosed IDDVT and no adequate information is available on the risk of IDDVT left untreated.
The present study, performed in outpatients with suspected leg DVT, aims at assessing the clinical consequences of IDDVT diagnosed (by a complete US investigation) but not treated because the results of this investigation remain blind to both the patient and the treating doctor, whereas the diagnostic-therapeutic procedure remains the usual one, based on CUS investigation limited to diagnose proximal DVT, to be repeated after 5-7 days (or earlier) to exclude an extension to proximal veins of an IDDVT potentially present.
Detailed description
Outpatients symptomatic for suspected DVT of a leg are examined by a vascular doctor according to standard procedure based on pre-test clinical probability (PTCP) assessment, D-dimer assay and a CUS limited to the proximal deep veins. Those in whom a proximal DVT is excluded and have intermediate/high PTCP or altered D-dimer level are eligible for the study. The included patients are immediately submitted to an extensive echo-color-Doppler examination of calf deep veins by a different vascular doctor and results are closed in an envelope that will be open after three months (or before if necessary). In the meantime, patients will follow the standard diagnostic procedure: they receive an appointment to come back in 5-7 days for a further CUS examination, or even before in case of worsening of symptoms/signs. All the included patients receive a telephone call after three months to exclude possible complications.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| 1 | – | Other: Ultrasound examination of leg veinsOutpatients with suspected leg DVT after exclusion of proximal DVT |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- outpatients with suspected deep vein thrombosis (DVT) of a leg in whom a proximal DVT is excluded. The study is not funded. As a result, it will not be possible to enroll all consecutive eligible patients; rather patients will be included based on the availability of expert medical staff in the day of their presentation (in general the first patient of the day).
Key inclusion criteria (2 listed)
- suspected deep vein thrombosis of a leg
- intermediate/high pre-test clinical probability or high D-dimer levels
Key exclusion criteria (12 listed)
- age < 18 years
- presence of proximal DVT
- suspected isolated iliac DVT
- symptoms/signs lasting from > 30 days
- presence of symptoms of pulmonary embolism
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Ultrasound examination of leg veinsOutpatients symptomatic for leg DVT follow the standard diagnostic procedure (ultrasound examination of proximal deep veins, pre-test clinical probability and D-dimer, and a second US after 5-7 days) to exclude proximal DVT; they also receive by another doctor a complete US examination of the deep leg veins to assess the presence of isolated calf DVT, the results of the latter examination are kept blind to the patient and to the treating doctor, and disclosed after three months | Other | 1 |
Primary outcome
Thrombotic complications (deep vein thrombosis and/or pulmonary embolism within three months from first examination
Time frame: three months from first examination
1 secondary outcome
other vascular complications; how many isolated distal DVT will be diagnosed
Time frame: three months from first examination
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 22 Mar 2021.
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Gualtiero Palareti, MD principal investigator
Azienda Ospedaliero-Universitaria di Bologna, Policlinico S. Orsola-Malpighi
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Isolated Distal DVT and Proximal DVT, run by IRCCS Azienda Ospedaliero-Universitaria di Bologna at 2 sites in Italy.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 12 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 22 Mar 2021. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in Italy. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Thrombotic complications (deep vein thrombosis and/or pulmonary embolism within three months from first examination (time frame: three months from first examination). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 22 Mar 2021; AzTrials last refreshed its copy on 8 Nov 2026.