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Risk of Developing Antibodies to Heparin-PF4 After Heart Surgery (HIT)

This study has been completed.
Information provided by (Responsible Party):
Duke University Identifier:
First received: October 11, 2005
Last updated: February 22, 2013
Last verified: February 2013
Heparin is a drug that is widely used to prevent and treat blood clotting. Individuals undergoing cardiopulmonary bypass surgery are administered high doses of heparin, and some of them develop antibodies to the drug. This immune response can lead to the formation of blood clots, setting the stage for a potential heart attack or stroke. The purpose of this study is to evaluate how often an immune response to heparin leads to the formation of blood clots in individuals who have had heart surgery.

Condition Intervention
Drug: Heparin

Study Type: Observational
Study Design: Observational Model: Cohort
Time Perspective: Prospective
Official Title: The Incidence of Thromboembolic Events in Patients With Antibodies to Heparin-PF4 After Cardiac Bypass

Resource links provided by NLM:

Further study details as provided by Duke University:

Primary Outcome Measures:
  • Thrombotic events compatible with HIT [ Time Frame: one year ]

Secondary Outcome Measures:
  • antibody positibe status post operative day 5 and day 30 [ Time Frame: one year ]

Enrollment: 1015
Study Start Date: June 2006
Study Completion Date: July 2012
Primary Completion Date: March 2009 (Final data collection date for primary outcome measure)
Intervention Details:
    Drug: Heparin
    Heparin will be used as the intra-operative anticoagulant
Detailed Description:

Heparin is a drug that is widely used to prevent and treat blood clotting. However, heparin can also cause serious adverse events. Individuals undergoing cardiopulmonary bypass surgery are administered and therefore exposed to high doses of heparin. Studies have shown that up to 61% of cardiac bypass patients develop elevated levels of antibodies to heparin-PF4 after surgery. This immune response may activate blood platelets, possibly resulting in a blood clot. These clots most often develop in the legs and lungs, and may lead to a heart attack or stroke. The frequency of such a reaction has yet to be determined definitively. This study will evaluate the incidence of an immune response to heparin-PF4 that leads to the formation of blood clots in individuals who have had heart surgery.

Participants in this study will be recruited prior to a scheduled cardiac bypass surgery. They will first complete a structured pre-operative interview to collect baseline measures on demographics, comorbidities, history of heparin exposures, and prior thromboembolic events. Immediately prior to surgery, a blood sample will be taken to assess the individual's platelet count and level of antibodies to heparin-PF4. Following the operation, participants will be followed daily to assess heparin exposure, platelet counts, and any blood clotting. Subsequent blood samples will be taken 5 days and 1 month following the surgery to again evaluate the individual's platelet count and level of heparin-PF4 antibodies. Additionally, participants will undergo a structured interview at 1 and 3 months post-surgery to evaluate the incidence of outcomes related to heparin-PF4 antibodies.


Ages Eligible for Study:   18 Years and older   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Sampling Method:   Non-Probability Sample
Study Population
Individuals undergoing cardiac bypass surgery with heparin as the intra-operative anticoagulant at Duke University Hospital.

Inclusion Criteria:

  • Scheduled for cardiac bypass surgery at Duke University Hospital

Exclusion Criteria:

  • Plans to receive warfarin during the post-operative inpatient stay
  • Plans to receive a full anticoagulant dose of low-molecular weight heparin during the post-operative inpatient stay
  • Plans to receive a full anticoagulant dose of unfractionated heparin during the post-operative inpatient stay
  • Use of any drug other than unfractionated heparin for anticoagulation during cardiopulmonary bypass
  • Warfarin, heparin, or low-molecular weight heparin administered during a readmission to the hospital for a reason other than one of this study's outcomes does not constitute criteria for exclusion
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT00237328

United States, Minnesota
Mayo Clinic, Rochester
Rochester, Minnesota, United States, 55905
United States, North Carolina
University of North Carolina
Chapel Hill, North Carolina, United States, 27599
Duke University Medical Center
Durham, North Carolina, United States, 27710
United States, Wisconsin
University of Wisconsin
Madison, Wisconsin, United States, 53706
Sponsors and Collaborators
Duke University
Principal Investigator: Thomas Ortel, MD, PhD Duke University
  More Information

Responsible Party: Duke University Identifier: NCT00237328     History of Changes
Other Study ID Numbers: Pro00010736
Study First Received: October 11, 2005
Last Updated: February 22, 2013

Keywords provided by Duke University:
Heparin resistance
Blood clotting
Heart surgery
Cardiopulmonary bypass

Additional relevant MeSH terms:
Embolism and Thrombosis
Vascular Diseases
Cardiovascular Diseases
Calcium heparin
Immunologic Factors
Physiological Effects of Drugs
Fibrinolytic Agents
Fibrin Modulating Agents
Molecular Mechanisms of Pharmacological Action processed this record on May 25, 2017