Monitoring Methods for Blood Clots

Overseen By Benjamin Tillman, MD

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: Vanderbilt University Medical Center

Must be taking: Unfractionated heparin

Disqualifiers: Extracorporeal membrane oxygenation, cerebrovascular ischemic event, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: Unknown

Duration: 5-7 days

2000 Participants Needed

Trial Summary

Will I have to stop taking my current medications?

The trial information does not specify whether you need to stop taking your current medications. It focuses on monitoring a specific blood thinner, unfractionated heparin, in the hospital.

What data supports the effectiveness of the drug Unfractionated Heparin for preventing blood clots?

Unfractionated Heparin is effective in preventing the extension of blood clots, especially in conditions like venous thromboembolic disease, by enhancing the body's natural clotting inhibitors. It is commonly monitored using tests like the activated partial thromboplastin time (aPTT) to ensure proper dosing and minimize bleeding risks. ^{1 2 3 4 5}

Is unfractionated heparin generally safe for humans?

Unfractionated heparin has been used for over 50 years and is important for treating blood clots, but it can cause bleeding and a rare but serious condition called heparin-induced thrombocytopenia (HIT), where the blood's ability to clot is affected. Monitoring is important to keep its levels safe, as incorrect dosing can lead to bleeding or clotting issues. ^{1 4 5 6 7}

How does the drug unfractionated heparin differ from other treatments for blood clots?

Unfractionated heparin (UFH) is unique because it has been used for over 50 years, but it requires careful monitoring due to its variable effects and risk of side effects like heparin-induced thrombocytopenia (a condition where the blood has a lower than normal number of platelets). Unlike newer anticoagulants, UFH's effects are less predictable and need frequent blood tests to ensure safe and effective dosing. ^{3 4 5 8 9}

What is the purpose of this trial?

Unfractionated heparin (UFH) is the most widely used intravenous (IV) anticoagulant for treating and preventing thromboembolic disease (e.g., blood clots ). UFH must be closely monitored and adjusted in the hospital. There are two assays used to monitor UFH: 1) the activated partial thromboplastin time (PTT) and 2) the chromogenic anti-factor Xa assay (anti-Xa). This study aims to compare PTT and anti-Xa methods for monitoring UFH in a pragmatic, randomized controlled trial to determine which helps patients reach a therapeutic anticoagulation range faster.

Research Team

Benjamin Tillman, MD

Principal Investigator

Vanderbilt University Medical Center

Eligibility Criteria

This trial is for hospitalized patients who need intravenous anticoagulation with unfractionated heparin to treat or prevent blood clots. Specific eligibility criteria are not provided, but typically participants would be adults without conditions that could interfere with the study.

Inclusion Criteria

Baseline PTT value is ≥0 and ≤ 36.0 seconds

Baseline heparin level anti-Xa assay value is ≥0 and ≤0.3

I am 18 or older and admitted to Vanderbilt University Hospital for treatment that includes IV heparin.

Exclusion Criteria

I need blood thinners due to a special heart-lung machine use or a stroke.

Provider determines patient is not appropriate for the study

Timeline

Screening

Participants are screened for eligibility to participate in the trial

1-2 weeks

Treatment

Participants are monitored using either the anti-Xa or PTT protocol for optimal monitoring of intravenous unfractionated heparin

5-7 days

Daily monitoring in hospital

Follow-up

Participants are monitored for safety and effectiveness after treatment, including incidence of new thrombotic and bleeding events

48 hours post-treatment

Treatment Details

Interventions

• Unfractionated Heparin

Trial Overview The trial compares two methods of monitoring the effectiveness of heparin: the PTT protocol and the anti-Xa protocol. It aims to find out which method helps patients reach the desired level of blood thinning more quickly.

Participant Groups

Group I: Active Comparator: anti-Xa protocol Active Control 1 Intervention

Patients randomized to this arm will be monitored using the pharmacy-managed anti-Xa protocol. This includes patients on both high- and low-dose heparin protocols.

Group II: Active Comparator: PTT protocol Active Control 1 Intervention

Patients randomized to this arm will be monitored using the nurse-managed PTT guided protocol. This includes patients on both high- and low-dose heparin protocols.

Who Is Running the Clinical Trial?

Vanderbilt University Medical Center

Lead Sponsor

Trials

922

Recruited

939,000+

Findings from Research

Unfractionated heparin (UFH) has been used for over 50 years to treat and prevent thrombosis, but its variable composition and unpredictable pharmacokinetics limit its effectiveness and complicate monitoring.

Newer anticoagulants, such as low-molecular-weight heparins and direct thrombin inhibitors, offer more predictable effects and eliminate the risk of heparin-induced thrombocytopenia (HIT), making them preferable alternatives to UFH.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Challenges in variation and responsiveness of unfractionated heparin. Francis, JL., Groce, JB.[2019]

References

1. United States pubmed.ncbi.nlm.nih.gov

Direct measurement of unfractionated heparin using a biochemical assay. [2019]

2. New Zealand pubmed.ncbi.nlm.nih.gov

Heparin 1986. Indications and effective use. [2018]

3. Germany pubmed.ncbi.nlm.nih.gov

Monitoring unfractionated heparin with the aPTT: time for a fresh look. [2006]

4. United States pubmed.ncbi.nlm.nih.gov

Heparin monitoring and patient safety: a College of American Pathologists Q-Probes study of 3431 patients at 140 institutions. [2021]

5. United States pubmed.ncbi.nlm.nih.gov

Challenges in variation and responsiveness of unfractionated heparin. [2019]

6. England pubmed.ncbi.nlm.nih.gov

Comparing safety of heparin as continuous intravenous infusion and multiple subcutaneous injections. [2015]

7. United States pubmed.ncbi.nlm.nih.gov

The use and limitations of unfractionated heparin. [2010]

8. England pubmed.ncbi.nlm.nih.gov

Determination of low-molecular-weight heparin by Heptest on the automated coagulation laboratory system. [2019]

9. United States pubmed.ncbi.nlm.nih.gov

High-Risk Non-ST Elevation Acute Coronary Syndrome Outcomes in Patients Treated with Unfractionated Heparin Monitored Using Anti-Xa Concentrations Versus Activated Partial Thromboplastin Time. [2022]