Thromboelastography With Platelet Mapping to Guide Antiplatelet Therapy After Lower Extremity Revascularization

May 21, 2026 updated by: Anahita Dua, MBCHB, MBA, MSC, Massachusetts General Hospital

The Use of Thromboelastography With Platelet Mapping to Guide Thromboprophylaxis Following Lower Extremity Revascularization for Peripheral Artery Disease

The goal of this clinical trial is to learn if a blood clotting test called thromboelastography with platelet mapping (TEG-PM) can guide blood-thinning medication decisions in adults 18 years and older with peripheral artery disease (PAD) who have undergone leg artery open or endovascular surgery. The main questions it aims to answer are:

  • Can TEG-PM results improve blood-thinning medication levels in participants at high risk for blood clots after surgery?
  • Can adjusting blood-thinning medications based on TEG-PM results lower the rate of blood clots forming in their revascularized leg after surgery?

Participants will:

  • Have blood samples taken before surgery and at 1 week, 1 month, 2 months, 3 months, 6 months, and up to 9 months after surgery
  • Have blood-thinning medications (aspirin, clopidogrel, and/or ticagrelor) adjusted based on TEG-PM results during the first 3 months after surgery
  • Have one additional blood test to check if clopidogrel is working properly
  • Have their medical records reviewed for 6 months after their last visit to check on their health outcomes

Study Overview

Status

Active, not recruiting

Conditions

Intervention / Treatment

Detailed Description

Background and Scientific Rationale:

Peripheral artery disease (PAD) frequently requires lower extremity revascularization via bypass surgery or endovascular stenting. Despite standard antiplatelet therapy, thrombosis occurs in up to 17% of patients within 6 months of revascularization. Current thromboprophylaxis strategies apply a uniform approach that fails to account for substantial interpatient variability in platelet response, including the fact that 60-65% of patients exhibit partial or complete resistance to aspirin or clopidogrel.

Thromboelastography with platelet mapping (TEG-PM) is a viscoelastic point-of-care test that provides a comprehensive assessment of the coagulation cascade, including clot initiation, kinetics, strength, fibrinolysis, and platelet function. TEG-PM measures adenosine diphosphate (ADP)-mediated platelet inhibition, reflecting P2Y12 pathway activity and clopidogrel effect, and arachidonic acid (AA)-mediated platelet inhibition, reflecting cyclooxygenase pathway activity and aspirin effect.

Prior prospective observational work by this group in 82 patients demonstrated that TEG-PM can identify individualized mechanisms of hypercoagulability prior to thrombotic events, providing a clinically actionable window for intervention. Patients who experienced thrombotic events showed significantly lower platelet inhibition and higher platelet aggregation than those who did not thrombose. Preliminary analysis identified platelet aggregation greater than 70.8% and platelet inhibition below 27.5% as associated with thrombosis with 85% sensitivity. The optimal cutoff for ADP maximum amplitude (MA) indicating higher thrombosis risk was greater than 42mm with 82% sensitivity.

TEG-Guided Antiplatelet Protocol:

This study implements a step-up approach to antiplatelet therapy guided by serial TEG-PM results using the following prespecified thresholds:

  • Platelet inhibition not greater than 30% AND platelet aggregation not less than 70% = high risk → therapy escalation
  • ADP MA not less than 42mm = high risk → therapy escalation
  • Values within therapeutic range → continue current regimen

Escalation follows this stepwise sequence:

  1. Aspirin monotherapy (81 mg daily)
  2. Dual antiplatelet therapy (DAPT) with aspirin and clopidogrel (75 mg daily)
  3. DAPT with aspirin and ticagrelor (90 mg twice daily) replacing clopidogrel
  4. Triple antiplatelet therapy (aspirin, clopidogrel, and ticagrelor) if platelet activity goals still not met

Participants with persistent high-risk TEG profiles despite ticagrelor are referred for genetic testing.

TEG-PM Blood Sampling and Analysis:

Two sample types are collected at each visit:

  • Citrated blood (sodium citrate Vacutainer tubes): incubated at room temperature for 10 minutes; analyzed using citrated multichannel cartridges to assess coagulation initiation, kinetics, clot strength, and fibrinolysis. Must be processed within 2-4 hours of collection.
  • Heparinized blood (sodium heparin Vacutainer tubes): incubated at room temperature for 30 minutes; analyzed using PlateletMapping cartridges to measure ADP-mediated and AA-mediated platelet aggregation and inhibition. - Must be processed within 2 hours of collection.

All samples are analyzed using the TEG 6s Hemostasis Analyzer (Haemonetics Corporation, Boston, MA) per manufacturer specifications. Up to two citrated tubes and one heparinized tube are drawn at each timepoint. In the event of insufficient blood volume, TEG-PM will be prioritized.

Study Phases:

  1. Pre-operative Phase:

    Blood sample collected within 48 hours before the planned revascularization procedure. If the procedure is delayed or rescheduled beyond this window, a new sample is collected.

  2. Interventional Phase (1 Week through Month 3):

TEG-PM results guide antiplatelet medication adjustments at the following visits:

  • 1 week (7-26 days post-procedure)
  • 1 month (27-54 days)
  • 2 months (55-84 days)
  • 3 months (85-149 days)

Unscheduled visits may occur if the principal investigator deems additional sampling necessary for patient safety, including readmission, clotting event, bleeding event, reintervention, inconclusive results, or medication change after 7 days.

Observational Phase (Month 6 through Month 9):

TEG-PM samples are collected at standard of care appointments. No medication adjustments are made during this phase:

  • 6 months (150-220 days)
  • 9 months (240-360 days): applicable only to participants still taking ticagrelor at the Month 6 visit

Medical Record Review:

Participants are followed for 6 additional months after their last sample collection visit via medical record review only to assess clinical outcomes.

Medication Adherence Criteria:

TEG-PM results are used to guide therapy only when participants are confirmed adherent:

  • Antiplatelet therapy: most recent dose taken within 7 days of sampling
  • Anticoagulant therapy: most recent dose taken within 72 hours of sampling

Clopidogrel Resistance Testing:

All participants undergo one-time clopidogrel resistance testing using the VerifyNow P2Y12 assay, an FDA-approved point-of-care test. Testing is performed at any post-operative study visit after the participant has been taking clopidogrel for at least 7 days. One citrated blood tube (3cc) is collected at MGH and couriered to Brigham and Women's Hospital hematology laboratory for analysis.

Disease Severity Assessment:

Peripheral artery disease severity is assessed at each study visit using the Rutherford Chronic Limb Ischemia Classification System based on standardized scripted questions addressing:

  • Walking frequency and distance before pain onset
  • Presence of rest pain or nocturnal pain
  • Presence of non-healing wounds

Study Type

Interventional

Enrollment (Estimated)

130

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Massachusetts
      • Boston, Massachusetts, United States, 02114
        • Massachusetts General Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Patients with a named arterial extremity injury or named vessel revascularization for atherosclerosis requiring open and/or closed revascularization
  • Patients at the age of 18 years or older

Exclusion Criteria:

  • Patients who are younger than 18 years old
  • Known pregnancy (females of childbearing potential will have a pregnancy test prior to surgery as per standard of care)
  • Prisoners, defined as those who have been directly admitted from a correctional facility
  • No atherosclerosis
  • Patient has a contraindication or allergy to antiplatelet medication and/or aspirin
  • Patient has contraindications to ticagrelor:
  • Active stomach ulcers
  • Severe hepatic impairment
  • History of intracranial hemorrhage
  • Previous allergic response to ticagrelor

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: TEG-PM Guided Antiplatelet Therapy
All participants undergo serial thromboelastography with platelet mapping (TEG-PM) before and after lower extremity revascularization for peripheral artery disease. Based on TEG-PM results, participants are classified as high risk or low risk for thrombosis. High risk participants (platelet inhibition ≤30%, platelet aggregation ≥70%, or ADP maximum amplitude ≥42 mm) undergo stepwise antiplatelet therapy escalation using aspirin, clopidogrel, and/or ticagrelor. Low risk participants whose results fall within the therapeutic range continue their current standard-of-care antiplatelet regimen without modification. All participants undergo one-time clopidogrel resistance testing using the VerifyNow P2Y12 assay.
Drug: Aspirin
Aspirin 81 mg orally once daily administered as first-line antiplatelet therapy. Used as monotherapy or as part of dual or triple antiplatelet therapy regimen based on TEG-PM results.
Other Names:
  • Acetylsalicylic Acid
Drug: Clopidogrel
Clopidogrel 75 mg orally once daily administered as second-line antiplatelet therapy when aspirin monotherapy fails to achieve therapeutic TEG-PM thresholds. Used as part of dual antiplatelet therapy with aspirin.
Other Names:
  • Plavix
Drug: Ticagrelor
Ticagrelor 90 mg orally twice daily administered when dual antiplatelet therapy with aspirin and clopidogrel fails to achieve therapeutic TEG-PM thresholds. Replaces clopidogrel in dual antiplatelet therapy or added as triple antiplatelet therapy if needed.
Other Names:
  • Brilinta
Diagnostic test: Platelet Reactivity Testing
One-time FDA-approved point-of-care platelet reactivity test performed to assess clopidogrel resistance. One citrated blood tube collected and analyzed after participant has been taking clopidogrel for at least 7 days.
Other Names:
  • VerifyNow P2Y12 Assay
Diagnostic test: Thromboelastography with Platelet Mapping
Serial whole blood samples analyzed using thromboelastography with platelet mapping to measure platelet inhibition, aggregation, and coagulation parameters at prespecified timepoints before and after lower extremity revascularization. Results are used to classify participants as high risk or low risk for thrombosis and to guide antiplatelet therapy adjustments.
Other Names:
  • TEG-PM

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Platelet Inhibition and Aggregation Following Antiplatelet Therapy Adjustment
Time Frame: Pre-operative baseline through 3 months post-revascularization
Determine if platelet inhibition and aggregation for participants with coagulation profiles that place them at high risk for thrombosis can be improved to levels not associated with thrombosis following alteration of antiplatelet therapy. High risk is defined as platelet inhibition not greater than 30%, platelet aggregation not less than 70%, or ADP maximum amplitude not less than 42mm on thromboelastography with platelet mapping.
Pre-operative baseline through 3 months post-revascularization

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Rate of Graft or Stent Thrombosis
Time Frame: Up to 12 months post-revascularization
Assess whether thrombotic rates decrease in participants who achieve improvement in platelet inhibition and aggregation levels to therapeutic targets following antiplatelet therapy adjustment guided by thromboelastography with platelet mapping.
Up to 12 months post-revascularization

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Primary, Primary Assisted, and Secondary Patency Rates
Time Frame: Up to 12 months post-revascularization
Assessment of patency rates of the revascularized arterial segment following lower extremity bypass or endovascular stenting procedure
Up to 12 months post-revascularization
Amputation Rate
Time Frame: Up to 12 months post-revascularization
Assessment of rate of limb amputation following lower extremity revascularization including documentation of any resultant intervention such as operative, interventional radiology, or medical management
Up to 12 months post-revascularization
Bleeding Events
Time Frame: Up to 12 months post-revascularization
Assessment of bleeding events including hemoglobin drop requiring transfusion, abnormal bruising, nosebleed requiring intervention, bleeding gums, and prolonged bleeding requiring return to operating room. Major bleeding defined as spontaneous bleeding requiring hospitalization.
Up to 12 months post-revascularization
Thrombosis and Resultant Intervention
Time Frame: Up to 12 months post-revascularization
Documentation of thrombotic events and any resultant intervention including operative, interventional radiology, or medical management following lower extremity revascularization
Up to 12 months post-revascularization

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Massachusetts General Hospital

Collaborators

Haemonetics Corporation

Investigators

  • Principal Investigator: Anahita Dua, MBChB, MBA, MSC, Massachusetts General Hospital

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

December 14, 2022

Primary Completion (Actual)

February 17, 2026

Study Completion (Estimated)

June 1, 2026

Study Registration Dates

First Submitted

May 13, 2026

First Submitted That Met QC Criteria

May 13, 2026

First Posted (Actual)

May 19, 2026

Study Record Updates

Last Update Posted (Actual)

May 26, 2026

Last Update Submitted That Met QC Criteria

May 21, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2022P002264 (Other Identifier: Mass General Brigham IRB)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

IPD Plan Description

Individual participant data sharing has not yet been determined. This is a single-site pilot study and data sharing decisions will be made following completion of data analysis and in accordance with Massachusetts General Hospital and Mass General Brigham institutional policies and target journal requirements.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

Yes

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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