Evaluating the Presence of Blood Clots in People With Heparin-Induced Thrombocytopenia (HIT) (The HOT Study)

NCT ID: NCT00594685

Last Updated: 2013-03-13

Basic Information

• Recruitment Status: TERMINATED
• Total Enrollment: 10 participants
• Study Classification: OBSERVATIONAL
• Study Start Date: 2008-01-31
• Study Completion Date: 2008-09-30

Brief 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. 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.

Conditions

Thrombocytopenia

Study Design

• Observational Model Type: CASE_ONLY
• Study Time Perspective: PROSPECTIVE

Study Groups

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

No interventions assigned to this group

Eligibility Criteria

Inclusion Criteria

• 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

Exclusion Criteria

• 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

• Minimum Eligible Age: 6 Months
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

National Heart, Lung, and Blood Institute (NHLBI)

NIH

Sponsor Role: collaborator

Carelon Research

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Susan F. Assmann, PhD

Role: PRINCIPAL_INVESTIGATOR

Carelon Research

Eliot C. Williams, MD, PhD

Role: PRINCIPAL_INVESTIGATOR

University of Wisconsin, Madison

Kenneth D. Friedman, MD

Role: PRINCIPAL_INVESTIGATOR

Froedtert Hospital

David Kress, MD

Role: PRINCIPAL_INVESTIGATOR

St. Luke's Medical Center

Ronald Go, MD

Role: PRINCIPAL_INVESTIGATOR

Gunderson Clinic

Keith McCrae, MD

Role: PRINCIPAL_INVESTIGATOR

Case Western Reserve University

Ellis Neufeld, MD

Role: PRINCIPAL_INVESTIGATOR

Boston Children's Hospital

Jeff Zwicker, MD

Role: PRINCIPAL_INVESTIGATOR

Beth Israel Deaconess Medical Center

Judith Lin, MD

Role: PRINCIPAL_INVESTIGATOR

Brigham and Women's Hospital

Thomas Ortel, MD, PhD

Role: PRINCIPAL_INVESTIGATOR

Duke University

Cassandra Josephson, MD

Role: PRINCIPAL_INVESTIGATOR

Emory University

Jodi Segal, MD, MPH

Role: PRINCIPAL_INVESTIGATOR

Johns Hopkins University

David Kuter, MD

Role: STUDY_CHAIR

Massachusetts General Hospital

Terry Gernsheimer, MD

Role: PRINCIPAL_INVESTIGATOR

University of Washington

Cindy Leissinger, MD

Role: PRINCIPAL_INVESTIGATOR

Tulane University

Thomas Raife, MD

Role: PRINCIPAL_INVESTIGATOR

University of Iowa

Ann Zimrin, MD

Role: PRINCIPAL_INVESTIGATOR

University of Maryland

Jeffrey McCullough, MD

Role: PRINCIPAL_INVESTIGATOR

University of Minnesota

Nigel Key, MB, MRCP

Role: PRINCIPAL_INVESTIGATOR

University of North Carolina

Ravindra Sarode, MD

Role: PRINCIPAL_INVESTIGATOR

University of Texas Southwestern Medical Center

Barbara Konkle, MD

Role: PRINCIPAL_INVESTIGATOR

University of Pennsylvania

Joseph Kiss, MD

Role: PRINCIPAL_INVESTIGATOR

University of Pittsburgh

Locations

Emory University

Atlanta, Georgia, United States

University of Iowa

Iowa City, Iowa, United States

Tulane University

New Orleans, Louisiana, United States

University of Maryland

Baltimore, Maryland, United States

Johns Hopkins Hospital

Baltimore, Maryland, United States

Massachusetts General Hospital

Boston, Massachusetts, United States

Brigham and Women's Hospital

Boston, Massachusetts, United States

Children's Hospital Boston

Boston, Massachusetts, United States

Beth Israel Deaconess Medical Center

Boston, Massachusetts, United States

University of Minnesota

Minneapolis, Minnesota, United States

University of North Carolina

Chapel Hill, North Carolina, United States

Duke University

Durham, North Carolina, United States

Case Western Reserve University

Cleveland, Ohio, United States

University of Pennsylvania

Philadelphia, Pennsylvania, United States

University of Pittsburgh

Pittsburgh, Pennsylvania, United States

University of Texas Southwestern Medical Center

Dallas, Texas, United States

University of Washington

Seattle, Washington, United States

Gunderson Lutheran Clinic

La Crosse, Wisconsin, United States

University of Wisconsin, Madison

Madison, Wisconsin, United States

St. Luke's Medical Center

Milwaukee, Wisconsin, United States

Froedtert Memorial Lutheran Hospital

Milwaukee, Wisconsin, United States

Countries

United States

Other Identifiers

U01HL072299

Identifier Type: NIH

Identifier Source: secondary_id

View Link

U01HL072299-01

Identifier Type: NIH

Identifier Source: secondary_id

View Link

U01HL072268

Identifier Type: NIH

Identifier Source: secondary_id

View Link

HL072033

Identifier Type: -

Identifier Source: secondary_id

HL072291

Identifier Type: -

Identifier Source: secondary_id

HL072289

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Identifier Source: secondary_id

HL072248

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Identifier Source: secondary_id

HL072191

Identifier Type: -

Identifier Source: secondary_id

HL072299

Identifier Type: -

Identifier Source: secondary_id

HL072305

Identifier Type: -

Identifier Source: secondary_id

HL072274

Identifier Type: -

Identifier Source: secondary_id

HL072028

Identifier Type: -

Identifier Source: secondary_id

HL072359

Identifier Type: -

Identifier Source: secondary_id

HL072072

Identifier Type: -

Identifier Source: secondary_id

HL072355

Identifier Type: -

Identifier Source: secondary_id

HL072283

Identifier Type: -

Identifier Source: secondary_id

HL072346

Identifier Type: -

Identifier Source: secondary_id

HL072331

Identifier Type: -

Identifier Source: secondary_id

HL072290

Identifier Type: -

Identifier Source: secondary_id

556

Identifier Type: -

Identifier Source: org_study_id