Reliability of Point-of-care INR Measurements in Patients With Antiphospholipid-antibody Syndrome Treated With Warfarin

This study has been completed.
Sponsor:
Collaborator:
International Technidyne Corporation
Information provided by (Responsible Party):
Lauren McKnight, PharmD, CPP, University of North Carolina, Chapel Hill
ClinicalTrials.gov Identifier:
NCT00878137
First received: April 6, 2009
Last updated: October 12, 2012
Last verified: October 2012
  Purpose

The antiphospholipid-antibody syndrome (APLA), which includes lupus anticoagulant, anticardiolipin, and anti-beta-2-glycoproteinI antibodies, is a thrombophilic disorder associated with arterial thrombosis, venous thrombosis or both. Patients diagnosed with APLA have a higher risk of recurrent thrombosis than do patients without known antibodies. Currently, warfarin is considered the anticoagulant of choice for prophylactic antithrombotic treatment for APLA patients after their first episode of thrombosis. In some patients with APLA who are treated with warfarin, the INR values determined on plasma are unreliable due to an influence of the APLA on the INR. In these individuals, alternative monitoring methods, such as factor II activity, chromogenic factor X activity or prothrombin-proconvertin time should be used to assess adequate anticoagulation. These tests are expensive and not widely available to some clinicians. Point-of-care (POC) instruments, on the other hand, are readily accessible to clinicians. Previous research has shown that INR values from 3 older point-of-care (POC) instruments are unreliable in 1/3 of APLA patients (CoaguChekTM, ProTimeTM, INRatioTM). However, there are now newer versions of these POC instruments available (CoaguChek XSTM, an investigational ProTime device, and a newer INRatioTM device) and it is unknown if these newer POC instruments are reliable in patients with APLA. The purpose of this study is to determine whether newer POC instruments are reliable in patients with APLA.


Condition Intervention
Antiphospholipid Syndrome
Device: INR by point-of-care instruments and venopuncture

Study Type: Observational
Study Design: Observational Model: Case Control
Time Perspective: Prospective
Official Title: INR Determined by Plasma-based Methods Versus Newer Point-of-care Instruments in Patients With Antiphospholipid-antibody Syndrome Treated With Anticoagulants

Resource links provided by NLM:


Further study details as provided by University of North Carolina, Chapel Hill:

Enrollment: 63
Study Start Date: March 2009
Study Completion Date: May 2009
Primary Completion Date: May 2009 (Final data collection date for primary outcome measure)
Groups/Cohorts Assigned Interventions
APLA
Patients with antiphospholipid antibody syndrome.
Device: INR by point-of-care instruments and venopuncture
Three fingersticks will be performed and from each one drop of capillary or venous whole blood collected from a fingerstick performed by the primary investigator to measure PT/INR using the CoaguChekXSTM (10 microliters), ProTimeTM (27 microliters), the investigational ProTime, and INRatioTM 15 microliters) point-of-care instruments and one i.v. blood draw (20 mL of blood) will be performed by a phlebotomist.
Control
Patients on warfarin therapy but without antiphosphilipid antibody syndrome.
Device: INR by point-of-care instruments and venopuncture
Three fingersticks will be performed and from each one drop of capillary or venous whole blood collected from a fingerstick performed by the primary investigator to measure PT/INR using the CoaguChekXSTM (10 microliters), ProTimeTM (27 microliters), the investigational ProTime, and INRatioTM 15 microliters) point-of-care instruments and one i.v. blood draw (20 mL of blood) will be performed by a phlebotomist.

  Eligibility

Ages Eligible for Study:   18 Years and older
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No
Sampling Method:   Non-Probability Sample
Study Population

APLA patients will be identified through the UNC Thrombophilia Program database. Control patients will be recruited at UNC Anticoagulation Clinic visits.

Criteria

APLA Inclusion Criteria:

  • Prolongation of a phospholipid-dependent screening assay, 2) lack of correction of a prolonged screening assay after a 1:1 mix with pooled normal plasma, and 3) correction of a prolonged screening assay by the addition of excess phospholipid. Two positive lupus anticoagulant confirmations at least 3 months apart will be required.
  • Diagnosis of anticardiolipin antibodies defined as elevated levels of ACA-IgG (>30) and/or ACA-IgM (>15) on two separate occasions at least 3 months apart.
  • Stable warfarin therapy, defined as the maintenance of a warfarin dose for a minimal of 2 weeks regardless of INR.

APLA Exclusion Criteria:

  • Patients whose warfarin dose has changed within the past 2 weeks.

Control Inclusion Criteria:

  • No evidence of either a positive LA or ACA diagnosis by confirmation of negative laboratory values and/or documentation of no clinical signs and symptoms concurrent with these conditions.
  • Stable warfarin therapy, defined as the maintenance of a warfarin dose for a minimal of 2 weeks regardless of INR.

Control Exclusion Criteria:

  • Patients whose warfarin dose has changed within the past 2 weeks.
  Contacts and Locations
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Please refer to this study by its ClinicalTrials.gov identifier: NCT00878137

Locations
United States, North Carolina
University of North Carolina at Chapel Hill
Chapel Hill, North Carolina, United States, 27514
Sponsors and Collaborators
University of North Carolina, Chapel Hill
International Technidyne Corporation
Investigators
Principal Investigator: Lauren B McKnight, PharmD University of North Carolina, Chapel Hill
  More Information

No publications provided

Responsible Party: Lauren McKnight, PharmD, CPP, Clinical Pharmacist, University of North Carolina, Chapel Hill
ClinicalTrials.gov Identifier: NCT00878137     History of Changes
Other Study ID Numbers: POC Comparison 08-1883
Study First Received: April 6, 2009
Last Updated: October 12, 2012
Health Authority: United States: Institutional Review Board

Additional relevant MeSH terms:
Antiphospholipid Syndrome
Autoimmune Diseases
Immune System Diseases
Antibodies
Antibodies, Antiphospholipid
Immunologic Factors
Physiological Effects of Drugs
Pharmacologic Actions

ClinicalTrials.gov processed this record on July 31, 2014