What question did this study set out to answer?

To evaluate the relationship between six activated partial thromboplastin time reagents, protamine titration, and chromogenic anti-Xa assays to assess the validity of a standard therapeutic range.

January 1, 1996Thrombosis and Haemostasis

The Therapeutic Range for Heparin Therapy: Relationship between Six Activated Partial Thromboplastin Time Reagents and Two Heparin Assays

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Why the study?

Does the choice of APTT reagent affect the therapeutic range for monitoring unfractionated heparin therapy?

Population

42 patients treated with unfractionated heparin for thromboembolic disease and normal subjects.

Design

Other

Authors

SKSteve KitchenUniversity of Sheffield FPF E PrestonGoethe University Frankfurt

Discussion

Member takes

Implication

Reagent-specific APTT calibration may be needed for heparin monitoring; leaves open whether this improves safety or efficacy.

Key Points

To evaluate the relationship between six activated partial thromboplastin time reagents, protamine titration, and chromogenic anti-Xa assays to assess the validity of a standard therapeutic range.
Assessed blood samples from N=42 patients treated with unfractionated heparin for thromboembolic disease, including 12 receiving concurrent warfarin with INR > 1.3.
Compared 6 manual APTT reagents and 2 coagulometer-paired reagents against heparin concentration measured by protamine titration and chromogenic anti-Xa assay.
In 30 patients with INR < 1.3, the APTT ratio range corresponding to therapeutic heparin (0.2–0.4 u/ml by protamine titration) varied widely from 1.6–1.9 for the least responsive reagent to 2.2–2.9 for the most responsive reagent.
The circulating heparin concentration associated with the conventional 1.5–2.5 APTT ratio varied twofold to threefold across different reagents.

Structured PICO

Does the choice of APTT reagent affect the therapeutic range for monitoring unfractionated heparin therapy?

Population

42 patients treated with unfractionated heparin for thromboembolic disease (12 receiving warfarin therapy with INR > 1.3, 30 with INR < 1.3) and normal subjects.

Intervention

Testing with 6 different APTT reagents using a manual technique, 2 of these reagents used in combination with a coagulometer, a heparin assay by protamine titration, and a chromogenic anti-Xa assay.

Outcome

Relationship between APTT ratios and heparin concentration across different reagents.surrogate

The widely used therapeutic APTT ratio range of 1.5-2.5 is not appropriate for all reagents due to significant variability in responsiveness to unfractionated heparin.

Cite This Study

Kitchen et al. (1996) studied this question.

synapsesocial.com/papers/6a70fd48e71d69abee08fa6a https://doi.org/10.1055/s-0038-1650358

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The Therapeutic Range for Heparin Therapy: Relationship between Six Activated Partial Thromboplastin Time Reagents and Two Heparin Assays

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

The Therapeutic Range for Heparin Therapy: Relationship between Six Activated Partial Thromboplastin Time Reagents and Two Heparin Assays

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

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Also Consider