The impact of COVID-19 and Long COVID for pulmonary embolism patients undergoing anticoagulation prior to COVID-19: a multicenter cohort study during omicron pandemic

<bold>Background:</bold> Coronavirus disease 2019 (COVID-19) infection and post-acute COVID-19 are linked to thromboembolic complications. The impact on pulmonary embolism (PE) patients, known for a pro-inflammatory state, remains unstudied under the pandemic. <bold>Methods:</bold> Observational, multicenter study was performed in seven teaching hospital in mainland China, based on the ongoing nationwide cohort study of PE. During the omicron pandemic in China between Dec 1st, 2022 to June 1st, 2023. Patients were followed-up to obtain the disease condition and outcomes related to COVID-19. Overlap weighting based on the propensity score matching was conducted among comparisons. <bold>Results:</bold> Out of 1032 PE patients, 694 (67.2%) contracted COVID-19; 47.8% were on anticoagulation. COVID-19 patients on anticoagulants had a higher bleeding risk (10.5%) compared to non-COVID-19 patients (2.2%, p<0.001), with the adjusted OR of 4.79 (95%CI 1.04-22.21, p=0.045). 202 individuals (29.1%) with COVID-19 reported long COVID-19. Survival curve presented a significant higher risk of long-term bleeding and venous thromboembolism (VTE) recurrence in those with long COVID (log-rank p=0.011 and p<0.0001, respectively). <bold>Conclusion:</bold> COVID-19 escalated the risk of bleeding in patients with history of PE who were under anticoagulation therapy. Patients with long COVID-19 exhibit a considerably increased risk of long-term bleeding and VTE recurrence. Close monitoring of coagulopathy complications and meticulous adjustment of anticoagulation strategies are crucial in the treatment of PE patients with COVID-19, particularly in those with long COVID-19.