scholarly journals Clinical outcomes with unfractionated heparin monitored by anti‐factor Xa vs. activated partial Thromboplastin time

2019 ◽  
Vol 94 (9) ◽  
pp. 1015-1019 ◽  
Author(s):  
James C. Coons ◽  
Carlo J. Iasella ◽  
Megan Thornberg ◽  
Mary Grace Fitzmaurice ◽  
Kimberly Goehring ◽  
...  
Keyword(s):  
Unfractionated Heparin ◽  
Clinical Outcomes ◽  
Partial Thromboplastin Time ◽  
Factor Xa ◽  
Activated Partial Thromboplastin Time

Effectiveness of a Calculation-Free Weight-Based Unfractionated Heparin Nomogram With Anti-Xa Level Monitoring Compared With Activated Partial Thromboplastin Time

2020 ◽  
pp. 106002802096150
Author(s):  
Nicole M. Kindelin ◽  
Ananth M. Anthes ◽  
Sarah M. Providence ◽  
Xinhua Zhao ◽  
Sherrie L. Aspinall
Keyword(s):  
Unfractionated Heparin ◽  
Partial Thromboplastin Time ◽  
Adverse Drug Events ◽  
Factor Xa ◽  
Primary Objective ◽  
Activated Partial Thromboplastin Time ◽  
Historical Control ◽  
Dose Calculations ◽  
Free Weight ◽  
Therapeutic Anticoagulation

Background Accurate monitoring of intravenous unfractionated heparin (UFH) is essential to mitigate the risk of adverse drug events associated with dosing errors. Although recent data support anti-factor Xa (anti-Xa) monitoring preferentially over activated partial thromboplastin time (aPTT) to improve time to therapeutic anticoagulation, the utility of incorporating anti-Xa monitoring with a calculation-free weight-based UFH nomogram has not been formally evaluated. Objective The primary objective of this study was to evaluate the time to therapeutic anticoagulation of a calculation-free weight-based UFH nomogram integrated with anti-Xa monitoring versus a historical control of aPTT monitoring utilizing manual dose calculations. Methods This was a retrospective analysis of patients with anti-Xa monitoring and a novel calculation-free weight-based UFH nomogram compared with a historical control with aPTT monitoring and manual calculations. Results A total of 103 patients in the aPTT cohort and 100 patients in the anti-Xa cohort were analyzed. The anti-Xa cohort achieved goal therapeutic target 3.8 hours sooner than the aPTT cohort ( P = 0.03). Patients with anti-Xa monitoring required 1 fewer adjustment per 2.5 patient-days of UFH with the venous thromboembolism nomogram ( P = 0.02). Patients in the aPTT cohort required more infusion interruptions because of supratherapeutic values ( P = 0.007) and boluses because of subtherapeutic values ( P = 0.044). There were no differences in rates of thromboembolism, major bleeding, or clinically relevant nonmajor bleeding between the cohorts. Conclusion and Relevance This study demonstrated that anti-Xa UFH monitoring integrated with a calculation-free nomogram results in faster time to therapeutic anticoagulation and fewer dose adjustments compared with aPTT monitoring with manual calculations.

Interlaboratory Precision in the Monitoring of Unfractionated Heparin Using the Anti-Factor Xa-Correlated Activated Partial Thromboplastin Time

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 435-435
Author(s):  
Adam Cuker ◽  
Beverly Ptashkin ◽  
Barbara A. Konkle ◽  
Steven W. Pipe ◽  
Herbert C. Whinna ◽  
...  
Keyword(s):  
Unfractionated Heparin ◽  
Therapeutic Range ◽  
Partial Thromboplastin Time ◽  
Factor Xa ◽  
Correlation Method ◽  
Activated Partial Thromboplastin Time ◽  
Laboratory Monitoring ◽  
Upper Limit ◽  
Accuracy And Precision ◽  
Therapeutic Category

Abstract Although the activated partial thromboplastin time (aPTT) remains the most widely used method for monitoring unfractionated heparin (UFH) therapy, it is affected by a number of preanalytic, analytic, and biological variables, which undermine both its accuracy and precision. In an effort to improve the accuracy and precision of laboratory monitoring of UFH, the College of American Pathologists (CAP) and the American College of Chest Physicians (ACCP) have issued guidelines recommending that the therapeutic range of the aPTT be defined in each laboratory through correlation with a direct measurement of heparin activity such as the factor Xa inhibition assay (anti-FXa). Whether and to what extent this approach enhances the precision of UFH monitoring has not been reported. We conducted a cross-validation study among 4 CAP-accredited coagulation laboratories to assess the interlaboratory precision of the anti-FXa-correlation method. An aPTT and anti-FXa were performed in each laboratory on plasma samples from 44 inpatients receiving UFH. Interlaboratory precision of the anti-FXa-correlation method was compared to that of the traditional 1.5–2.5 times the upper limit of normal (ULN) method for defining the therapeutic aPTT range. Modest to poor intralaboratory correlation between the aPTT and anti-FXa was observed in each of the 4 laboratories. The coefficients of determination (R2) ranged from 0.1962 to 0.6964. In accordance with CAP guidelines, the anti-FXa-derived therapeutic aPTT range was defined by linear regression corresponding to a range of anti-FXa activity of 0.3 – 0.7 units/ml. In each laboratory, the range defined by this method was broader than that defined using the ULN method. In 3 of the laboratories, the therapeutic range defined by the anti-FXa-correlation method extended more than 20 seconds beyond the upper limit of the therapeutic range defined by the ULN approach. Based on the laboratory-specific therapeutic ranges defined by both methods, samples were segregated into therapeutic category [i.e. below therapeutic (BT), therapeutic (T), or above therapeutic (AT)]. Using the ULN method, there was agreement among all 4 laboratories regarding the therapeutic category in 22 (50%) samples, whereas consensus was achieved in only 7 (16%) samples with the anti-FXa-correlation method. Furthermore, 3 (7%) samples were simultaneously determined to be BT and AT in different laboratories by the anti-FXa-correlation method, suggesting that the dose of UFH might be increased in one center and decreased in another for the same patient encounter. This striking discrepancy was not observed with the ULN method. In conclusion, the anti-FXa-correlation method for defining the therapeutic range of the aPTT does not enhance the interlaboratory precision of UFH laboratory monitoring and may be inferior to the ULN method in this regard. Clinical studies are needed to assess the impact of these findings on patient safety.

scholarly journals Design and Implementation of an Anti–Factor Xa Heparin Monitoring Protocol

2020 ◽  
Vol 31 (2) ◽  
pp. 129-137
Author(s):  
Tanya Williams-Norwood ◽  
Megan Caswell ◽  
Barbara Milner ◽  
Joseph C. Vescera ◽  
Kelly Prymicz ◽  
...  
Keyword(s):  
Unfractionated Heparin ◽  
Partial Thromboplastin Time ◽  
Factor Xa ◽  
Heparin Therapy ◽  
Activated Partial Thromboplastin Time ◽  
Monitoring Protocol ◽  
Protocol Conversion ◽  
Therapeutic Anticoagulation ◽  
Intravenous Heparin ◽  
Heparin Dosage

Background: The VA Northeast Ohio Healthcare System introduced a new nurse-driven anti–factor Xa (anti-Xa) protocol for monitoring unfractionated heparin to replace the previous activated partial thromboplastin time protocol. Objective: To design, implement, and evaluate the efficacy of the anti-Xa monitoring protocol. Methods: An interdisciplinary team of providers collaborated to develop and implement a nurse-driven, facility-wide anti–factor Xa protocol for monitoring unfractionated heparin therapy. The effectiveness of this protocol was evaluated by retrospective analysis. Results: We reviewed 100 medical records for compliance with the new anti-Xa monitoring protocol. We then evaluated 178 patients whose anticoagulation was monitored with the anti-Xa assay to determine the time to therapeutic range. We found that 80% of patients receiving the anti-Xa protocol achieved therapeutic anticoagulation within 24 hours, as compared with 54% of patients receiving the activated partial thromboplastin time protocol (P < .001). Protocol conversion also yielded a decrease in blood draws, dose adjustments, and potential calculation errors. Conclusions: Monitoring intravenous heparin therapy with the anti-Xa assay rather than activated partial thromboplastin time resulted in a shorter time to therapeutic anticoagulation, longer maintenance of therapeutic levels, and fewer laboratory tests and heparin dosage changes. We believe the current practice of monitoring heparin treatment with activated partial thromboplastin time assays should be reexamined.

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