Objective:

We sought to determine whether Anti-factor-Xa (AFXa) values are associated
with outcomes in cerebral venous thrombosis (CVT).

Background:

Intravenous unfractionated heparin (UFH) is a cornerstone of anticoagulant
therapy for patients with CVT, but frequent monitoring is needed because of dose-response variability. The AFXa assay is used to monitor UFH treatment.

Design/Methods:

This pilot study included adults (≥18y) admitted to a comprehensive stroke center
from 2018 through 2020 who were initially treated for CVT with low-intensity UFH drip and had at least one AFXa assay. AFXa therapeutic values were defined as 0.25 – 0.5 IU/mL. We examined percent of patients who became therapeutic within 24h of arrival, and time (hours, h) to reach therapeutic range. Outcomes included hospital LOS, bleeding event, and discharge disposition. Continuous data are presented as median (interquartile range).

Results:

There were 51 CVT patients included. The time to start UFH was 2h (1-6) from
arrival and the time to the first AFXa assay was 8h (4-11) from arrival. AFXa were drawn 4 (2-8) times per patient. AFXa assays were performed within 24h for 45 (88%) patients and 30(67%) patients were in the therapeutic range. There was no association between study outcomes and AFXa being therapeutic or not: bleeding events were 17.2% and 13.3%, respectively (p=1.0), discharge to home was 77% vs. 80% (p=1.0), and hospital LOS was 5 days for each group (p=0.95). There was also no association between study outcomes and the time (h) to reach therapeutic range: discharge home vs. other location (11h vs. 14h, p=0.49), development of a bleed vs. no bleed (9h vs. 12h, p=0.44), and no correlation with hospital LOS (p=0.55).

Conclusions:

The time to achieve therapeutic AFXa was not associated with outcomes,
although most patients were within the target AFXa range within 24h of arrival and had favorable outcomes.