Comparison of unfractionated heparin protocols using antifactor Xa monitoring or activated partial thrombin time monitoring

Abstract

The antifactor Xa assay should be used to monitor UFH versus aPTT due to less variability in measurements, the absence of a need for calibration with new reagents/coagulometers, quicker attainment of therapeutic levels, fewer dose adjustments, and similar bleeding rates.

The effect of heparin infusion intensity on outcomes for bridging hospitalized patients with atrial fibrillation

“…Studies have suggested that monitoring UFH infusions with anti-Xa levels compared to aPTT is superior in maintaining values within goal range. 21,22 However, therapeutic dosing of UFH with regards to safety and efficacy has been guided by aPTT, not anti-Xa levels in clinical trials, mostly acute coronary syndrome. This study did not assess the difference in bleeding events and the type of monitoring used (aPTT or anti-Xa).…”

“…Differences in physician, pharmacy and nursing practice can affect the degree of UFH infusion prescribing, dosing, titration, and monitoring. Studies have suggested that monitoring UFH infusions with anti‐Xa levels compared to aPTT is superior in maintaining values within goal range . However, therapeutic dosing of UFH with regards to safety and efficacy has been guided by aPTT, not anti‐Xa levels in clinical trials, mostly acute coronary syndrome.…”

Should we abandon the APTT for monitoring unfractionated heparin?

“…Several studies have reported the discordance of the APTT with anti-Xa values in monitoring heparin (15)(16)(17)(18)(19) and many studies have focused on one particular age group, either infants (18) or adults (16;17;19). One study demonstrated that nearly 57% of patients in the anti-Xa group were in range within 6 hours of initiation of UFH versus 27% in the APTT group (p = 0.001) (20). Patients in the anti-Xa group had an average of 1.00 dosage adjustments per subject compared to 1.71 in the APTT group within the first 24 hours (p = 0.003) (20).…”

“…One study demonstrated that nearly 57% of patients in the anti-Xa group were in range within 6 hours of initiation of UFH versus 27% in the APTT group (p = 0.001) (20). Patients in the anti-Xa group had an average of 1.00 dosage adjustments per subject compared to 1.71 in the APTT group within the first 24 hours (p = 0.003) (20). (40%) concordance of APTT and anti-Xa values (19).…”

Anti-Xa assays: What is their role today in antithrombotic therapy?

“…Fewer dose adjustments and repeat tests are required, which may also result in lower cost. 32,[51][52][53][54][55] While these studies found chromogenic anti-Xa assays better for achieving laboratory end points, data regarding relevant clinical outcomes are more limited. In a retrospective, observational cohort study, 51 the rate of venous thromboembolism or bleeding-related death was 2% in patients receiving unfractionated heparin therapy monitored by anti-Xa assay and 6% in patients monitored by aPTT (P = .62).…”