What question did this study set out to answer?

To determine the linear and log-linear correlation between activated clotting time (ACT) or activated partial thromboplastin time (aPTT) and plasma heparin concentration, and to assess the therapeutic consequences of dosage decisions guided by each test.

August 1, 1999Pharmacotherapy The Journal of Human Pharmacology and Drug Therapy

Correlation of Activated Clotting Time and Activated Partial Thromboplastin Time to Plasma Heparin Concentration

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Why the study?

Do ACT and aPTT correlate with plasma heparin concentration in patients receiving continuous-infusion intravenous heparin?

Population

30 patients receiving continuous-infusion intravenous heparin at a university-affiliated community hospital

Comparison

Measurement of activated clotting time and… vs Plasma heparin concentration

Design

Cohort

Authors

JKJohn M. KoerberEugene Applebaum College of Pharmacy and Health Sciences MSMaureen A. SmytheWayne State University RBRobert L. BegleUniversity of Wisconsin–Madison

Discussion

Member takes

Implication

aPTT may guide continuous heparin dosing more reliably than ACT; hypothesis-generating without outcome data.

Key Points

To determine the linear and log-linear correlation between activated clotting time (ACT) or activated partial thromboplastin time (aPTT) and plasma heparin concentration, and to assess the therapeutic consequences of dosage decisions guided by each test.
Two-phase prospective study conducted in 30 patients receiving continuous-infusion intravenous heparin at a university-affiliated community hospital.
Measured ACT, aPTT, and plasma heparin concentrations, followed by linear and log-linear correlation analyses and decision analysis modeling dosage adjustments.
Linear correlation with plasma heparin concentration yielded r=0.58 (p=0.008) for ACT and r=0.89 (p=0.0001) for aPTT; log-linear correlation yielded r=0.60 (p=0.005) for ACT and r=0.88 (p=0.0001) for aPTT.
ACT-based dosage decisions disagreed with plasma heparin in 15 of 30 patients (13 risked bleeding, 2 risked thrombosis), whereas aPTT-based decisions disagreed in 13 of 30 patients (2 risked bleeding, 11 risked thrombosis).

Structured PICO

Do ACT and aPTT correlate with plasma heparin concentration in patients receiving continuous-infusion intravenous heparin?

Population

30 patients receiving continuous-infusion intravenous heparin at a university-affiliated community hospital

Intervention

Measurement of activated clotting time (ACT) and activated partial thromboplastin time (aPTT)

Comparator

Plasma heparin concentration

Outcome

Correlation between ACT or aPTT and plasma heparin concentrationsurrogate

While aPTT shows a stronger correlation with plasma heparin concentration than ACT, both tests may lead to discordant dosing decisions that could increase bleeding or thrombosis risks.

Cite This Study

Koerber et al. (1999) studied this question.

synapsesocial.com/papers/6a70fd48e71d69abee08fa68 https://doi.org/10.1592/phco.19.11.922.31573

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Correlation of Activated Clotting Time and Activated Partial Thromboplastin Time to Plasma Heparin Concentration

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Correlation of Activated Clotting Time and Activated Partial Thromboplastin Time to Plasma Heparin Concentration

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

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