Background: While the use of vitamin K antagonists (VKAs) has markedly reduced since the introduction of direct oral anticoagulants (DOACs), they are still the anticoagulant of choice for certain patients. The COVID-19 pandemic has resulted in anticoagulation clinics having to adapt services to ensure that anticoagulation is safely monitored, while minimising viral transmission to patients and staff. Contingency planning for staff absences also needed to be considered.
Aims: To review the success of the strategies adapted for outpatient management of VKAs during the Covid-19 pandemic.
Methods: Patients attending the anticoagulation clinic were managed as per the algorithm in Figure 1. Performance of the clinic was monitored using time in therapeutic range (TTR) and extreme INR values <1.5 and >4.5 during this time period using DAWN® anticoagulation software.
Covid-19 Pathway
Results: 504 patients required INR monitoring during the pandemic (See Figure 2). A total of 8588 INR tests were carried out with an overall TTR of 74% and 6% of extreme INR values. The percentage time in range of the Covid-19 pathway patients was 39% (15/39) of which 17% (7/39) had extreme INR values. There were a total of 314 days of Covid-19 leave due to contact isolation and vulnerable staff in the department. 
Anticoagulant Clinic Overview
Conclusions: Under normal circumstances, patients on VKAs require regular monitoring to ensure safe and efficacious anticoagulation. Covid-19 patients require more frequent monitoring when ill due to changes in their oral intake and commencement of interacting medications.
The global Covid-19 pandemic has made regular monitoring of these patients more difficult due to the potential for spread of the virus between patients and staff. However, following a global review of the service, proper monitoring and patient care has been safely achieved by the careful triage of patients, the use of personal protective equipment and the use of virtual consultations.
To cite this abstract in AMA style:
O'Leary C, Silvari V, Browne C, O'Flynn P, Chappell P, Duggan C, Crowley M. Managing Outpatients on Vitamin K Antagonists (VKAs) during the COVID-19 Pandemic in a Tertiary Referral Hospital [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 2). https://abstracts.isth.org/abstract/managing-outpatients-on-vitamin-k-antagonists-vkas-during-the-covid-19-pandemic-in-a-tertiary-referral-hospital/. Accessed June 25, 2022.« Back to ISTH 2021 Congress
ISTH Congress Abstracts - https://abstracts.isth.org/abstract/managing-outpatients-on-vitamin-k-antagonists-vkas-during-the-covid-19-pandemic-in-a-tertiary-referral-hospital/