PB0089 - Anticoagulants after COVID-19 pneumonia for patients with low thrombotic risk

Background: According to ISTH guidelines for antithrombotic treatment in COVID-19, anticoagulant treatment after COVID-19 is indicated only for patients with high thrombotic risk at discharge.

Aims: To investigate the need for anticoagulants after COVID-19 in patients with low thrombotic risk at discharge.

Methods: Main group – 40 patients (age – 60,5 (53,8; 67,3), men – 21 (52,5 %)) recovered from COVID-19 pneumonia. They received enoxaparin 0,4 mg twice a day during COVID-19. They did not have thrombosis during COVID-19 and were discharged with normal levels of D-dimer and IMPROVE VTE score < 4. They were divided into 2 subgroups: 1 – 16 patients who did not receive anticoagulants after discharge; 2 – 24 patients who received rivaroxaban. Observation time – 160,0 (118,8; 160,0) days from COVID-19 beginning. Log-rank test and Cox regression analysis were used.

Results: Subgroups 1 and 2 were comparable in age, sex and comorbidity. However, subgroup 2 had higher body mass index, more severe respiratory failure and higher levels of C-reactive protein during COVID-19 pneumonia. The more severe course of COVID-19 in subgroup 2 was the reason for anticoagulant prescription according to medical standards in Ukraine.
There were 7 (43,8 %) cases of VTE (pulmonary embolism) in subgroup 1 and 0 cases in subgroup 2. Difference between subgroups were significant (p < 0,01). VTE happened at 40,0 (33,0; 52,5) day from COVID-19 beginning, that equaled 16,0 (13,0; 20,5) day after anticoagulant withdrawal. Anticoagulant withdrawal in subgroup 1 – 22,0 (19,9; 28,0) day from COVID-19 beginning, in subgroup 2 – 65,0 (60,0; 90,0) (p < 0,01). There was not a single case of serious bleeding. Hazard ratio between subgroup 1 and subgroup 2 was 13,6 (1,7; 110,7).

Conclusion(s): Patients with low thrombotic risk at discharge may benefit from anticoagulant treatment after discharge. Absence of anticoagulants increases risks of thrombosis in 13 times.