The Value of Screening for HPR in Patients Undergoing Lower Extremity Arterial Endovascular Interventions

January 3, 2024 updated by: Marissa Jarosinski

The Value of Screening for "High on Treatment Platelet Reactivity" in Patients Undergoing Lower Extremity Arterial Endovascular Interventions

This is a randomized controlled trial designed to evaluate the role of screening for and intervening on patients with high on treatment platelet reactivity undergoing lower extremity arterial endovascular interventions.

Study Overview

Detailed Description

Peripheral arterial disease (PAD) affects millions of people worldwide. Management of PAD has evolved from open surgery to an endovascular first approach leading to increased volume of endovascular interventions. Endovascular femoropopliteal intervention has emerged as a standard treatment for symptomatic PAD with acceptable patency rates.

Histologic observation of bare metal stents with early failure shows association with platelet rich thrombus, high counts of platelets, and neutrophils associated with stent struts. Additionally, high inflation pressures associated with balloon angioplasty often causes local tissue damage leading to platelet activation. These findings led to studies targeting platelet activation following endovascular treatment showing improved outcomes in patients receiving stronger platelet inhibition.

The current standard of care is prescription of dual antiplatelet therapy (DAPT) for femoropopliteal angioplasty or stenting. DAPT is active use of any two antiplatelet agents, often low dose aspirin plus P2Y12 inhibitor (clopidogrel, ticagrelor, prasugrel). There is improved stent patency and reduced adverse cardiovascular events in patients taking DAPT versus aspirin monotherapy.

Clopidogrel is the most common additional antiplatelet agent prescribed, but 4-65% of patients taking clopidogrel fail to achieve clinically expected platelet inhibition. This persistent platelet reactivity despite compliant antiplatelet use is commonly referred to as high on-treatment platelet reactivity (HPR), and increases risk of endovascular intervention failure and associated adverse clinical events in these patients. Clopidogrel is a pro-drug metabolized by CYP2C19 enzyme into its active form. Failure to respond appropriately to clopidogrel is largely due to genetic polymorphisms within CYP2C19 enzyme resulting in variable metabolization of clopidogrel into the active metabolite.

Alternative antiplatelet medications can overcome HPR through different metabolic pathways, but unfortunately at a significantly higher cost. Of these, ticagrelor is often used to overcome HPR for patients taking clopidogrel with favorable outcomes. However, regional cost for ticagrelor is $352.50 compared to $1.96 for clopidogrel. Cost and bleeding concerns among providers have prevented widespread use. Overall, there is paucity of evidence looking at HPR and lower extremity arterial endovascular interventions without consensus or guidelines on how to address this problem. Thus, the investigators propose an unblinded, randomized controlled trial in patients having femoropopliteal angioplasty or stenting comparing two strategies: 1. testing and treating for HPR versus 2. guideline based therapy without testing for HPR.

Study Type

Interventional

Enrollment (Estimated)

296

Phase

  • Phase 3

Contacts and Locations

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

Study Contact

Study Locations

    • Pennsylvania
      • Pittsburgh, Pennsylvania, United States, 15213
        • Recruiting
        • University of Pittsburgh Medical Center
        • Contact:
          • Kyle Markel

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

18 years to 90 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Peripheral arterial disease
  • Planned angioplasty or stenting of superficial femoral artery or popliteal artery.

Exclusion Criteria:

  • Patients treated on an emergency basis
  • Planned intervention on prior site of open surgical intervention (autogenous or autologous bypass, endarterectomy, or patch angioplasty)
  • Planned intervention at site exclusive of superficial femoral artery or popliteal artery
  • Planned re-stenting at site of prior stent placement
  • Planned re-angioplasty at site of prior angioplasty
  • Known inability to tolerate antiplatelet regimen before enrollment
  • Patients who plan on receiving follow up care outside the University of Pittsburgh Medical Center
  • Current use of prasugrel or ticlopidine
  • Current use of oral anticoagulation medication
  • Pregnant patients

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: Screening
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Experimental: screening/treating for HPR
Participants randomized to this arm will be screened and treated for HPR. Pharmacogenetics testing for CYP2C19 polymorphisms will be collected, stored, and analyzed at study completion.
HPR testing using VerifyNow testing system. HPR is defined platelet reactivity units are greater than 234
Participants who test positive for HPR will be prescribed ticagrelor 90mg twice daily instead of standard therapy with clopidogrel 75mg daily
No Intervention: Control: guideline based therapy
Participants randomized to this arm will receive usual care without screening for HPR. Pharmacogenetics testing for CYP2C19 polymorphisms will be collected, stored, and analyzed at study completion.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Proportion of participants with primary patency
Time Frame: one year from intervention
primary patency is freedom from re-intervention, freedom from complete vessel occlusion, freedom from >50% restenosis with duplex ultrasound or freedom from >70% restenosis with computed tomography angiography
one year from intervention

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
proportion of participants with amputation
Time Frame: one year from intervention
Freedom from new amputation on the lower extremity intervened on during study
one year from intervention
Correlation of HPR testing results
Time Frame: after study completion
Correlation of HPR results between VerifyNow and CYP2C19 pharmacogenetics testing
after study completion
Major adverse cardiovascular events
Time Frame: one year from intervention
Any new stroke, myocardial infarction, death during study
one year from intervention

Collaborators and Investigators

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

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)

August 9, 2019

Primary Completion (Estimated)

December 31, 2024

Study Completion (Estimated)

December 31, 2025

Study Registration Dates

First Submitted

July 1, 2019

First Submitted That Met QC Criteria

July 1, 2019

First Posted (Actual)

July 5, 2019

Study Record Updates

Last Update Posted (Actual)

January 5, 2024

Last Update Submitted That Met QC Criteria

January 3, 2024

Last Verified

January 1, 2024

More Information

Terms related to this study

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

Yes

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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