PB0423 - Anti-Xa activity test is needed but not enough for monitoring fondaparinux therapy among critically ill patients

Sunday, June 23, 2024

13:45 – 14:45 ICT

Room: Exhibition Hall

Presenting Author(s)

Liqin Ling

Senior diagnostician
West China hosptial, Sichuan University
Chengdu, Sichuan, China (People's Republic)

Co-Author(s)

Chaonan Liu, MD

None
West China Hospital, Sichuan University
Chengdu, Sichuan, China (People's Republic)
XH

Xunbei Huang

Senior diagnostician
West China Hospital, Sichuan University
Chengdu, Sichuan, China (People's Republic)
SL

Siqi Liu

Technician
Panzhihua Central Hospital
Panzhihua, Sichuan, China (People's Republic)
JL

Juan Liao

Senior technician
West China Hospital, Sichuan University
Chengdu, Sichuan, China (People's Republic)
JJ

Jin Jia

Senior technician
West China Hospital, Sichuan University
Chengdu, Sichuan, China (People's Republic)
YF

Yang Fu

Accosiate Professor
West China Hospital, Sichuan University
Chengdu, Sichuan, China (People's Republic)
JZ

Jing Zhou

Professor
West China Hospital, Sichuan University
Chengdu, Sichuan, China (People's Republic)

Background: Fondaparinux monitoring is not needed among noncritically ill patients, in which it has a predictable dose-response effect. However, this rule is debatable among critically ill patients, in which the bioavailability of fondaparinux could be influenced by complicated medical conditions.

Aims: This study gets insight into fondaparinux monitoring among the critically ill in intensive care unit (ICU).

Methods: Retrospective analysis of patients admitted in ICU from February 2021 to December 2021, who received fondaparinux therapy and had anti-Xa activity tests.

Results: 156 anti-Xa results from 70 patients were included. Only 18/156 (11.5%) anti-Xa were within 0.39-0.50 IU/mL, the expected concentration suggested by manufacturer, demonstrating an unpredictable dose-response effect. Besides, anti-Xa was not different among patients with different coagulation-related outcomes, indicating a weak practicability of anti-Xa testing for monitoring fondaparinux efficacy. Only thrombin-antithrombin complex (TAT) was different between patients with controlled thrombotic tendency and patients with progressed thrombosis. After fondaparinux treatment, TAT showed a gradual decline in the former group, while it showed a bounce-back effect in the latter group. Only thrombelastography (TEG) R value was different between patients with or without bleeding events. TEG R value above upper reference value was much more noticeable in the former group (4/6) compared to the latter group (4/22) (P=.012).

Conclusion(s): Fondaparinux dose-response effect among the critically ill was unpredictable, so it is absolutely necessary to monitor fondaparinux therapy in ICU. However, anti-Xa activity testing is not enough for this purpose in this population; it should be combined with TAT and TEG R value.