AUTHOR=Clark Chantal C. , Jukema Bernard N. , Barendrecht Arjan D. , Spanjaard Judith S. , Jorritsma Nikita K. N. , Smits Simone , de Maat Steven , Seinen Cor W. , Verhoef Sandra , Parr Naomi M. J. , Sebastian Silvie A. E. , Koekman Arnold C. , van Wesel Annet C. W. , van Goor Harriet M. R. , Spijkerman Roy , Bongers Suzanne H. , van der Vries Erhard , Nierkens Stefan , Boes Marianne , Koenderman Leo , Kaasjager Karin A. H. , Maas Coen 

TITLE=Thrombotic Events in COVID-19 Are Associated With a Lower Use of Prophylactic Anticoagulation Before Hospitalization and Followed by Decreases in Platelet Reactivity

JOURNAL=Frontiers in Medicine

VOLUME=8

YEAR=2021

URL=https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2021.650129

DOI=10.3389/fmed.2021.650129

ISSN=2296-858X

ABSTRACT=<p><bold>Background:</bold> Coronavirus disease of 2019 (COVID-19) is associated with a prothrombotic state and a high incidence of thrombotic event(s) (TE).</p><p><bold>Objectives:</bold> To study platelet reactivity in hospitalized COVID-19 patients and determine a possible association with the clinical outcomes thrombosis and all-cause mortality.</p><p><bold>Methods:</bold> Seventy nine hospitalized COVID-19 patients were enrolled in this retrospective cohort study and provided blood samples in which platelet reactivity in response to stimulation with ADP and TRAP-6 was determined using flow cytometry. Clinical outcomes included thrombotic events, and all-cause mortality.</p><p><bold>Results:</bold> The incidence of TE in this study was 28% and all-cause mortality 16%. Patients that developed a TE were younger than patients that did not develop a TE [median age of 55 vs. 70 years; adjusted odds ratio (AOR) = 0.96 per 1 year of age, 95% confidence interval (CI) 0.92–1.00; <italic>p</italic> = 0.041]. Furthermore, patients using preexisting thromboprophylaxis were less likely to develop a thrombotic complication than patients that were not (18 vs. 54%; AOR = 0.19, 95% CI 0.04–0.84; <italic>p</italic> = 0.029). Conversely, having asthma strongly increased the risk on TE development (AOR = 6.2, 95% CI 1.15–33.7; <italic>p</italic> = 0.034). No significant differences in baseline P-selectin expression or platelet reactivity were observed between the COVID-19 positive patients (<italic>n</italic> = 79) and COVID-19 negative hospitalized control patients (<italic>n</italic> = 21), nor between COVID-19 positive survivors or non-survivors. However, patients showed decreased platelet reactivity in response to TRAP-6 following TE development.</p><p><bold>Conclusion:</bold> We observed an association between the use of preexisting thromboprophylaxis and a decreased risk of TE during COVID-19. This suggests that these therapies are beneficial for coping with COVID-19 associated hypercoagulability. This highlights the importance of patient therapy adherence. We observed lowered platelet reactivity after the development of TE, which might be attributed to platelet desensitization during thromboinflammation.</p>