Heparin Prophylaxis Dosing for Antepartum Hospitalizations (HEPDOSE)

Study Overview
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Brief Summary
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This study is a randomized control trial to compare gestational age-based dosing with standard dosing of unfractionated heparin for thromboprophylaxis of hospitalized antepartum patients. The investigators aim to determine the effect of dosing on receipt of neuraxial anesthesia and pregnancy outcomes and evaluate the pharmacokinetics and pharmacodynamics of unfractionated heparin in pregnancy.

Detailed Description
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Venous thromboembolism is one of the leading causes of maternal morbidity and mortality, and antepartum hospitalizations place pregnant patients at an even higher risk of developing thromboembolism. As a result, there is an increased emphasis on administering pharmacologic thromboprophylaxis for antepartum patients with prolonged hospitalizations. Previously, standard dosing of unfractionated heparin was widely adopted for thromboprophylaxis in the pregnant population. However, due to a suspected altered metabolism of unfractionated heparin in pregnancy resulting in a decrease response, the American College of Obstetricians and Gynecologists (ACOG) currently recommends considering gestational age-based dosing for unfractionated heparin for thromboprophylaxis in pregnancy with standard dosing as an alternative option. The data supporting altered dosing is very limited. In addition, increased dosing of heparin may result in challenges in anesthetic management, potentially limiting the receipt of neuraxial anesthesia resulting in increased need for general anesthesia associated with both increased maternal and fetal risks. The potential effects of higher prophylactic unfractionated heparin dosing in pregnant patients need to be further explored before being widely adopted for inpatient antepartum thromboprophylaxis. The investigators propose this study to provide a direct comparison of gestational age-based unfractionated heparin dosing to standard dosing of unfractionated heparin for pharmacologic thromboprophylaxis of hospitalized antepartum patients.

Official Title
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Randomized Control Trial of Unfractionated Heparin Thromboprophylaxis Dosing for Antepartum Hospitalizations

Conditions
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Pregnancy Related, Antepartum DVT

Intervention / Treatment
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* Drug: Standard Dose of Unfractionated Heparin
* Drug: Gestational Age-Based Dose of Unfractionated Heparin


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: At least 18 years of age Speak English or Spanish Antepartum admission for at least 72 hours at Ronald Reagan UCLA Medical Center Provides informed consent for study participation Exclusion Criteria: Active or threatened antenatal bleeding Disseminated intravascular coagulation Risk of imminent delivery (delivery within 12 hours) Thrombocytopenia (platelet count < 100 x 109) Elevated baseline aPTT (> 36.2 seconds) Concern for hemolysis, elevated liver enzymes, low platelet count (HELLP) syndrome Congenital bleeding disorders (hemophilias) Receiving therapeutic or prophylactic anticoagulation (unfractionated heparin, low molecular weight heparin, oral anticoagulants) for alternative indication (e.g., acquired or inherited thrombophilia, history of VTE) History of heparin-induced thrombocytopenia (HIT) SARS-CoV-2 positive Cognitive impairment, psychiatric instability, or language barriers that limit their ability to provide informed consent Presence of a condition or abnormality that in the opinion of the Investigator would compromise the safety of the patient or the quality of the data.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Standard Dosing<br>Standard dose of unfractionated heparin | Drug: Standard Dose of Unfractionated Heparin<br>* 5,000 units subcutaneous unfractionated heparin every 12 hours<br>|
| Active Comparator: Gestational Age-Based Dosing<br>Dose of unfractionated heparin based on trimester of pregnancy | Drug: Gestational Age-Based Dose of Unfractionated Heparin<br>* First trimester (< 14 weeks of gestation): 5,000 units subcutaneous unfractionated heparin every 12 hours Second trimester (14-28 weeks of gestation): 7,500 units subcutaneous unfractionated heparin every 12 hours Third trimester (> 28 weeks of gestation): 10,000 units subcutaneous unfractionated heparin every 12 hours<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of Participants With Elevated Serum Activated Partial Thromboplastin Time Above the Normal Range (> 36.2 Seconds). | Surrogate marker for whether or not the patient would be eligible for neuraxial anesthesia based on guidelines for neuraxial anesthesia in pregnant women receiving VTE prophylaxis | Collected 6 hours after unfractionated heparin dose until patient was taken of unfractionated heparin, an average of 1 week | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of Participants Diagnosed With Venous Thromboembolism (Pulmonary Embolism and/or Deep Venous Thromboembolism) |  | Assessed throughout hospitalization, an average length of 8 days, until 6 weeks after delivery | 
| Number of Participants Who Did Not Receive or Had a Delay of Neuraxial Anesthesia Due to Unfractionated Heparin |  | Assessed at time of delivery | 
| Number of Participants That Received General Anesthesia |  | Assessed at time of delivery | 
| Number of Participants That Had a Delay in Timing of Delivery Due to Unfractionated Heparin |  | Assessed at time of delivery | 
| Maximum Anti-Factor Xa Level Measured |  | Collected 6 hours after unfractionated heparin dose until patient was taken of unfractionated heparin, an average of 1 week | 
| Mode of Delivery |  | Assessed at time of delivery | 
| Estimated Blood Loss From Delivery |  | Assessed at time of delivery | 
| Number of Participants That Received a Blood Transfusion |  | From time of delivery until 6 weeks after delivery | 
| Maximum Activated Partial Thromboplastin Clotting Time Levels Measured |  | Collected 6 hours after unfractionated heparin dose until patient was taken of unfractionated heparin, an average of 1 week | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Thromboprophylaxis, Antepartum admission, Heparin