Risk of Developing Antibodies to Heparin-PF4 After Heart Surgery

Study Overview
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Brief Summary
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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.

Detailed Description
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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.

Official Title
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The Incidence of Thromboembolic Events in Patients With Antibodies to Heparin-PF4 After Cardiac Bypass

Conditions
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Thrombosis

Intervention / Treatment
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* Drug: Heparin


Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Intervention/Treatment |
| --- |
|Drug: Heparin|Heparin will be used as the intra-operative anticoagulant|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Thrombotic events compatible with HIT |  | one year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| antibody positibe status post operative day 5 and day 30 |  | one year | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Heparin resistance, Blood clotting, Heart surgery, Cardiopulmonary bypass