ThrombocytopeniaHOTNCT00594685
Evaluating the Presence of Blood Clots in People With Heparin-Induced Thrombocytopenia (HIT) (The HOT Study)
An observational study of Thrombocytopenia, run by Carelon Research at 21 sites in United States.
Trial summary
Heparin-induced thrombocytopenia (HIT), a condition characterized by low platelet levels and possible blood clots, occurs in a small number of people after treatment with the drug heparin. Read more about this study
- Who is it for?
- Ages 6 months and older
- Conditions the study is for
- Thrombocytopenia
- How many people
- 10 participants
- Where
- 21 sitesUnited States
- Study dates
- Jan 2008to Sep 2008
- Phase
- Observational
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
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 6 months and older
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
Study population: Inpatients at participating clinical centers who have a diagnosis of isolated Heparin-Induced Thrombocytopenia (HIT), determined by a fall in platelet count after heparin treatment and a positive Platelet Factor 4 (PF4)-heparin Enzyme-Linked ImmunoSorbent Assay (ELISA) test
Who may be able to join
- In the 72 hours prior to study entry, participant has been diagnosed with "isolated HIT," as defined by an unexplained platelet count drop of over 50% that occurs after exposure to UFH (UnFractionated Heparin)/LMWH (Low Molecular Weight Heparin) at any time in the 4 to 14 days before the positive heparin-PF4 antibody test was sent(even if the person is no longer on UFH/LMWH)
- Currently hospitalized
- Available for study follow-up for at least 28 days after study entry
- No contraindications to ultrasound examination of upper and lower extremities
- For participants less than 7 years old, no contraindications to ultrasound examination of abdomen
- Participants are eligible whether or not they are receiving any therapy for isolated HIT
Who cannot join
- Documented new venous or arterial thrombosis while on heparin
- Pregnant
- Ongoing active bleeding (as determined by the site investigator)
- Currently using a extracorporeal membrane oxygenator, chronic veno-venous hemofiltration, left ventricular support device, intra-aortic balloon pump, or any other mechanical heart pump
- Coronary artery bypass surgery occured within 96 hours prior to the time when the positive HIT test was drawn
Trial locations and contacts
21 sites in 1 country.
21 sites in 1 country
United States21 sites
Emory University
Atlanta, Georgia, 30322
University of Maryland
Baltimore, Maryland, 21201
Johns Hopkins Hospital
Baltimore, Maryland, 21205
Massachusetts General Hospital
Boston, Massachusetts, 02114
Brigham and Women's Hospital
Boston, Massachusetts, 02115
Children's Hospital Boston
Boston, Massachusetts, 02115
Beth Israel Deaconess Medical Center
Boston, Massachusetts, 02215
University of North Carolina
Chapel Hill, North Carolina, 27599
Case Western Reserve University
Cleveland, Ohio, 44106
University of Texas Southwestern Medical Center
Dallas, Texas, 75390
Duke University
Durham, North Carolina, 27710
University of Iowa
Iowa City, Iowa, 52242
Gunderson Lutheran Clinic
La Crosse, Wisconsin, 54601
University of Wisconsin, Madison
Madison, Wisconsin, 53792
St. Luke's Medical Center
Milwaukee, Wisconsin, 53215
Froedtert Memorial Lutheran Hospital
Milwaukee, Wisconsin, 53226
University of Minnesota
Minneapolis, Minnesota, 55455
Tulane University
New Orleans, Louisiana, 70112
University of Pennsylvania
Philadelphia, Pennsylvania, 19104
University of Pittsburgh
Pittsburgh, Pennsylvania, 15213
University of Washington
Seattle, Washington, 98104
About this study
Official title: HIT Observational Thromboembolism Study (A TMH CTN Study)
Heparin-induced thrombocytopenia (HIT), a condition characterized by low platelet levels and possible blood clots, occurs in a small number of people after treatment with the drug heparin. Some people with HIT may show symptoms of a blood clot at the time of HIT diagnosis, but in another form of HIT, known as isolated HIT, people do not show blood clot symptoms even though they might have a blood clot. This study will use ultrasound tests to evaluate the presence of blood clots at the time of an HIT diagnosis and in the following month.
Read the detailed description
Heparin is a blood thinning medication that is often prescribed to treat or prevent blood clots. HIT is a life-threatening immune disorder that occurs in 1 to 3% of people who receive heparin. In this disorder, heparin does the opposite of what it is supposed to do: it promotes new blood clot formation, rather than preventing it. In people with HIT, the immune system triggers a response against heparin, leading to the destruction of platelets and a low platelet count, which is known as thrombocytopenia. Symptoms usually occur between 5 to 14 days after starting heparin therapy. Isolated HIT is a form of the condition that occurs when people have a low platelet count, but there is no sign of a blood clot, or thrombosis. Several small research studies have shown that at the time of isolated HIT diagnosis, between 15 to 50% of people actually have asymptomatic thrombosis, which means that they are not showing any signs of a blood clot, but in fact have one. In the month following HIT diagnosis, up to 50% of people experience symptomatic thrombosis, which means that they are showing signs of a blood clot. It is not currently known how to best treat isolated HIT and how to test for unrecognized blood clots. This study will use ultrasound imaging to evaluate the number of people who have asymptomatic thrombosis at the time of isolated HIT diagnosis and to determine the rate of symptomatic and asymptomatic thrombosis in the following month. The results of this study will assist researchers in assessing current approaches to treating isolated HIT and in designing new clinical trials. By exploring the use of non-invasive evaluation techniques in people with HIT, thrombosis research in HIT will move forward, similar to thrombosis research in other medical conditions.
This 29-day study will enroll hospital patients who have a diagnosis of HIT but show no signs of a blood clot at the time of HIT diagnosis. On Day 1, participants will undergo blood collection and an ultrasound. While participants are in the hospital, study researchers will review participants' medical records on a daily basis to collect data on current medications, medication compliance, symptoms, bleeding, thrombosis complications, and laboratory test results. Once participants leave the hospital, this data will be collected at least once a week through phone calls with the participant and/or the treating physician. On Day 29, participants will undergo a repeat ultrasound and blood collection.
- Conditions
- Thrombocytopenia
- Keywords
- Heparin, Thromboembolism, Thrombosis
- Medical subject headings
- Thrombocytopenia, Thromboembolism, Thrombosis
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| Isolated HIT | Hospitalized patients with isolated Heparin-Induced Thrombocytopenia (HIT), diagnosed by a fall in platelet count and a positive Platelet Factor 4 (PF4)-heparin Enzyme-Linked ImmunoSorbent Assay (ELISA) test |
What is being measured
The primary outcome is the main question the study is designed to answer.
The Percentage of Participants With Asymptomatic Thrombosis at the Time Isolated Heparin-Induced Thrombocytopenia (HIT) is Diagnosed, Determined by Four-limb Ultrasound
The percentage of participants with asymptomatic thrombosis at the time isolated HIT is diagnosed as determined by four-limb ultrasound.
Measured: Measured at Day 1
Secondary outcomes (12)
The Percentage of Participants With Asymptomatic Thrombosis 4 Weeks After the Diagnosis of Isolated HIT, Determined by Four-limb Ultrasound
The percentage of participants with asymptomatic thrombosis 4 weeks after the diagnosis of isolated HIT, determined by four-limb ultrasound, and 95% exact binomial confidence interval.
Measured: Measured at Day 35 (+/- 7days)
The Number of Participants With Symptomatic Venous or Arterial Thromboembolism in the Month Following the Diagnosis of Isolated HIT
There were two versions of the data collection form used in this study, and only the revised version collected information on whether the event was symptomatic.
Measured: Measured within 35 days (+/- 7) after the diagnosis of isolated HIT
The Number of Participants With Incidental Arterial and Venous Thromboembolism (i.e., a Clot Diagnosed by Radiographic Tests Done for Reasons Other Than to Diagnose or Rule Out a Thromboembolic Event)
There were two versions of the data collection form used in this study, and only the revised form contained information on whether the event was incidental.
Measured: Measured within 35 days (+/- 7) after the diagnosis of isolated HIT
The Time to First Bleeding Event With Current Therapies for Isolated HIT
The time to first bleeding event was analyzed using survival analysis.
Measured: Measured within 35 days (+/- 7) after the diagnosis of isolated HIT
Time Until Death From All Causes
The time until death from all causes, in days, was determined using survival analysis.
Measured: Measured within 35 days (+/- 7) after the diagnosis of isolated HIT
Time to Platelet Count Recovery
The time to platelet recovery was defined as the time from the nadir platelet count observed in the five days after the positive HIT test was sent to observing a platelet count of 100K or greater. Survival analysis was used.
Measured: Measured within 35 days (+/- 7) after the diagnosis of isolated HIT
Number of Days That Medications Were Given to Participants at Participating Institutions
Per the protocol, descriptive statistics on the types and durations of therapeutic approaches used will be presented.
Measured: Measured within 35 days (+/- 7) after the diagnosis of isolated HIT
Length of Hospital Stay
The length of time between the date of HIT diagnosis and first hospital discharge was calculated. Subjects were censored at death. Survival analysis was used.
Measured: Measured upon hospital discharge
Length of Hospital Stay (With Deaths Not Censored)
The length of time between the date of HIT diagnosis and first hospital discharge was calculated. Subjects were not censored at death. Survival analysis was used.
Measured: Measured upon hospital discharge
Relationship Between the Platelet Factor 4 (PF4)-Heparin Enzyme-Linked ImmunoSorbent Assay (ELISA) Test, the Serotonin-release Assay, and D-dimer Test Results
Analysis not performed since central laboratory tests were not done.
Measured: Measured at Day 1
Relationship Between PF4-heparin ELISA Test, Serotonin-release Assay, and D-dimer Test Results and Thromboembolism
Analysis not performed since central laboratory tests were not done.
Measured: Measured at Day 1 and within 35 days (+/- 7) after the diagnosis of isolated HIT
Relationship Between the Presence of the Factor V Leiden Mutation or the Prothrombin 20210 Mutation and the Risk of Thrombosis
Analysis not performed since central laboratory tests were not done.
Measured: Measured at Day 1 and within 35 days (+/- 7) after the diagnosis of isolated HIT
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted16 Jan 2008 (estimated)
- Study startJan 2008
- Primary completionSep 2008
- Study completionSep 2008
Why it stopped: Low accrual rate
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for ThrombocytopeniaStudies of the same condition, open and under way.
- 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
- Case only
- Time perspective
- Prospective
- Enrolment
- 10 participants (actual)
Sponsor and investigators
- Lead sponsor
- Carelon Research
- Sponsor type
- University, hospital or other
- Collaborators
- National Heart, Lung, and Blood Institute (NHLBI)
- Responsible party
- Sponsor
- Investigators
- Susan F. Assmann, PhD, Principal investigator, Carelon ResearchEliot C. Williams, MD, PhD, Principal investigator, University of Wisconsin, MadisonKenneth D. Friedman, MD, Principal investigator, Froedtert HospitalDavid Kress, MD, Principal investigator, St. Luke's Medical CenterRonald Go, MD, Principal investigator, Gunderson ClinicKeith McCrae, MD, Principal investigator, Case Western Reserve UniversityEllis Neufeld, MD, Principal investigator, Boston Children's HospitalJeff Zwicker, MD, Principal investigator, Beth Israel Deaconess Medical Center
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT00594685
- Sponsor's protocol ID
- 556
- Other IDs
- U01HL072299, U01HL072299-01, U01HL072268, HL072033, HL072291, HL072289, HL072248, HL072191
- Acronym
- HOT
- Status last verified
- Mar 2013
- First submitted
- 7 Jan 2008
- Last updated
- 13 Mar 2013
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- Yes
Study at a glance
From the registry record, last updated by the sponsor on 13 Mar 2013. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- HIT Observational Thromboembolism Study (A TMH CTN Study)
- ClinicalTrials.gov ID
- NCT00594685
- Acronym / sponsor ID
- HOT / 556
- Conditions
- Thrombocytopenia
- Keywords
- Heparin, Thromboembolism, Thrombosis
- Study type
- Observational
- Recruitment status
- TerminatedReason stopped: Low accrual rate
- Enrolment
- 10 participants (actual)
- Lead sponsor
- Carelon ResearchUniversity, hospital or other
- Collaborators
- National Heart, Lung, and Blood Institute (NHLBI)
- Study start
- Jan 2008
- Primary completion
- Sep 2008 (actual)
- Study completion
- Sep 2008 (actual)
- First posted
- 16 Jan 2008 (estimated)
- Results
- Posted 9 Mar 2010
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Heparin-induced thrombocytopenia (HIT), a condition characterized by low platelet levels and possible blood clots, occurs in a small number of people after treatment with the drug heparin. Some people with HIT may show symptoms of a blood clot at the time of HIT diagnosis, but in another form of HIT, known as isolated HIT, people do not show blood clot symptoms even though they might have a blood clot. This study will use ultrasound tests to evaluate the presence of blood clots at the time of an HIT diagnosis and in the following month.
Detailed description
Heparin is a blood thinning medication that is often prescribed to treat or prevent blood clots. HIT is a life-threatening immune disorder that occurs in 1 to 3% of people who receive heparin. In this disorder, heparin does the opposite of what it is supposed to do: it promotes new blood clot formation, rather than preventing it. In people with HIT, the immune system triggers a response against heparin, leading to the destruction of platelets and a low platelet count, which is known as thrombocytopenia. Symptoms usually occur between 5 to 14 days after starting heparin therapy. Isolated HIT is a form of the condition that occurs when people have a low platelet count, but there is no sign of a blood clot, or thrombosis. Several small research studies have shown that at the time of isolated HIT diagnosis, between 15 to 50% of people actually have asymptomatic thrombosis, which means that they are not showing any signs of a blood clot, but in fact have one. In the month following HIT diagnosis, up to 50% of people experience symptomatic thrombosis, which means that they are showing signs of a blood clot. It is not currently known how to best treat isolated HIT and how to test for unrecognized blood clots. This study will use ultrasound imaging to evaluate the number of people who have asymptomatic thrombosis at the time of isolated HIT diagnosis and to determine the rate of symptomatic and asymptomatic thrombosis in the following month. The results of this study will assist researchers in assessing current approaches to treating isolated HIT and in designing new clinical trials. By exploring the use of non-invasive evaluation techniques in people with HIT, thrombosis research in HIT will move forward, similar to thrombosis research in other medical conditions.
This 29-day study will enroll hospital patients who have a diagnosis of HIT but show no signs of a blood clot at the time of HIT diagnosis. On Day 1, participants will undergo blood collection and an ultrasound. While participants are in the hospital, study researchers will review participants' medical records on a daily basis to collect data on current medications, medication compliance, symptoms, bleeding, thrombosis complications, and laboratory test results. Once participants leave the hospital, this data will be collected at least once a week through phone calls with the participant and/or the treating physician. On Day 29, participants will undergo a repeat ultrasound and blood collection.
Study design
- Observational model
- Case only
- Time perspective
- Prospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Isolated HIT | – | –Hospitalized patients with isolated Heparin-Induced Thrombocytopenia (HIT), diagnosed by a fall in platelet count and a positive Platelet Factor 4 (PF4)-heparin Enzyme-Linked ImmunoSorbent Assay (ELISA) test |
Who may qualify
- Ages
- 6 months and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
- Study population
- Inpatients at participating clinical centers who have a diagnosis of isolated Heparin-Induced Thrombocytopenia (HIT), determined by a fall in platelet count after heparin treatment and a positive Platelet Factor 4 (PF4)-heparin Enzyme-Linked ImmunoSorbent Assay (ELISA) test
Key inclusion criteria (6 listed)
- In the 72 hours prior to study entry, participant has been diagnosed with "isolated HIT," as defined by an unexplained platelet count drop of over 50% that occurs after exposure to UFH (UnFractionated Heparin)/LMWH (Low Molecular Weight Heparin) at any time in the 4 to 14 days before the positive heparin-PF4 antibody test was sent(even if the person is no longer on UFH/LMWH)
- Currently hospitalized
- Available for study follow-up for at least 28 days after study entry
- No contraindications to ultrasound examination of upper and lower extremities
- For participants less than 7 years old, no contraindications to ultrasound examination of abdomen
Key exclusion criteria (5 listed)
- Documented new venous or arterial thrombosis while on heparin
- Pregnant
- Ongoing active bleeding (as determined by the site investigator)
- Currently using a extracorporeal membrane oxygenator, chronic veno-venous hemofiltration, left ventricular support device, intra-aortic balloon pump, or any other mechanical heart pump
- Coronary artery bypass surgery occured within 96 hours prior to the time when the positive HIT test was drawn
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
The Percentage of Participants With Asymptomatic Thrombosis at the Time Isolated Heparin-Induced Thrombocytopenia (HIT) is Diagnosed, Determined by Four-limb Ultrasound
Time frame: Measured at Day 1
The percentage of participants with asymptomatic thrombosis at the time isolated HIT is diagnosed as determined by four-limb ultrasound.
12 secondary outcomes
The Percentage of Participants With Asymptomatic Thrombosis 4 Weeks After the Diagnosis of Isolated HIT, Determined by Four-limb Ultrasound
Time frame: Measured at Day 35 (+/- 7days)
The Number of Participants With Symptomatic Venous or Arterial Thromboembolism in the Month Following the Diagnosis of Isolated HIT
Time frame: Measured within 35 days (+/- 7) after the diagnosis of isolated HIT
The Number of Participants With Incidental Arterial and Venous Thromboembolism (i.e., a Clot Diagnosed by Radiographic Tests Done for Reasons Other Than to Diagnose or Rule Out a Thromboembolic Event)
Time frame: Measured within 35 days (+/- 7) after the diagnosis of isolated HIT
The Time to First Bleeding Event With Current Therapies for Isolated HIT
Time frame: Measured within 35 days (+/- 7) after the diagnosis of isolated HIT
Time Until Death From All Causes
Time frame: Measured within 35 days (+/- 7) after the diagnosis of isolated HIT
Time to Platelet Count Recovery
Time frame: Measured within 35 days (+/- 7) after the diagnosis of isolated HIT
Number of Days That Medications Were Given to Participants at Participating Institutions
Time frame: Measured within 35 days (+/- 7) after the diagnosis of isolated HIT
Length of Hospital Stay
Time frame: Measured upon hospital discharge
Length of Hospital Stay (With Deaths Not Censored)
Time frame: Measured upon hospital discharge
Relationship Between the Platelet Factor 4 (PF4)-Heparin Enzyme-Linked ImmunoSorbent Assay (ELISA) Test, the Serotonin-release Assay, and D-dimer Test Results
Time frame: Measured at Day 1
Relationship Between PF4-heparin ELISA Test, Serotonin-release Assay, and D-dimer Test Results and Thromboembolism
Time frame: Measured at Day 1 and within 35 days (+/- 7) after the diagnosis of isolated HIT
Relationship Between the Presence of the Factor V Leiden Mutation or the Prothrombin 20210 Mutation and the Risk of Thrombosis
Time frame: Measured at Day 1 and within 35 days (+/- 7) after the diagnosis of isolated HIT
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 13 Mar 2013.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
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rhTPO for Thrombocytopenia in Chronic Liver Disease Patients Undergoing Elective Invasive Procedures.
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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.
Susan F. Assmann, PhD principal investigator
Carelon Research
Eliot C. Williams, MD, PhD principal investigator
University of Wisconsin, Madison
Kenneth D. Friedman, MD principal investigator
Froedtert Hospital
21 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Thrombocytopenia, run by Carelon Research at 21 sites in United States.
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 6 inclusion and 5 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: stopped early, as of the sponsor's last update on 13 Mar 2013. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 21 sites in United States. 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?
Yes. Results are posted in the registry (first posted 9 Mar 2010). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
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?
The Percentage of Participants With Asymptomatic Thrombosis at the Time Isolated Heparin-Induced Thrombocytopenia (HIT) is Diagnosed, Determined by Four-limb Ultrasound (time frame: Measured at Day 1). 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 13 Mar 2013.