Background: In patients with severe COVID-19, activation of blood coagulation and endothelial cells orchestrated with complement activation and cytokine storm leads to disease worsening and death. Hypercoagulable state and endothelial cell activation and fibrinolytic unbalance are common alterations in patients with COVID-19 hospitalized either at the conventional medical ward or at the intensive care unit (ICU). Two systematic reviews highlight that D-dimer values are higher in non survivors as well as in patients with severe COVID-19 than in those with mild disease, showing the association between D-dimer levels and disease severity or death. Nevertheless, there are limited data in small series of patient, on the persistence of hypercoagulability and endothelial cell activation following recovery from COVID-19.

Aims: To investigate the persistence of endothelial cell activation and hypercoagulability after recovery from COVID-19. Patients/Methods. COVID-19 survivors (n = 208) and 30 healthy individuals were enrolled in this study.

Methods: In ,total, 208 COVID-19 survivors were included in the study; 125 males (60%) and 83 females (40%) with a median age of 50 years (IQR = 20, range 18 to 78 years). Biomarkers of hypercoagulability and endothelial cell activation: The procoagulant phospholipid-dependent clotting time (PPL-ct) was measured using a factor Xa-based clotting assay STA®-Procoag-PPL. Free-TFPI levels were measured with the ELISA Free TFPI, Asserachrom®; D-dimer and fibrin monomers (FM) were measured by STA Liatest D-Di and STA Liatest FM; soluble thrombomodulin (sTM) was measured by Asserachrom® TM. All assays were from Diagnostica Stago, Asnières, France. Heparanase-levels were measured with ELISA kits R&D. Systems (Lille France). Detection of anti-SARS-CoV2 antibodies: IgG and IgA anti-SARS-CoV-2 antibodies were detected in the sera of the survivors using a semi-quantitative commercial ELISA methodology (Euroimmun Medizinische Labordiagnostika AG, Lubeck, Germany)

Results: The median interval between symptom onset and screening for SARS-CoV-2 antibodies was 62 days (IQR = 22 days). Antibodies against SARS-CoV-2 were detected in all survivors enrolled in the study. The median level of IgG and IgA antibodies was 5.68 U (IQR = 6.19) and 3.62 U (IQR = 5.36), respectively. In 112 survivors with known blood group, 48 (43%) were group O, 44 (39%) were group A, 14 (13%) were group B, and 6 (5.4%) were group AB. Survivors showed significantly higher levels of D-Dimers, FM, TFPI, and heparanase as compared to that of the control group. Survivors had significantly shorter PPL-ct . One out of four of COVID-19 survivors showed increase at least one biomarker of endothelial cell activation or hypercoagulability (Table1). Elevated D-dimer was associated with older age. Elevated FM was associated with female gender. Elevated heparanase was independently associated with male gender. Decreased Procoag-PPL clotting time was associated with female gender. Univariate and multivariate logistic regression analysis examining predictors of hypercoagulability in study cohort of COVID-19 survivors are reported in table 2 . The interval between COVID-19 diagnosis and assessment was not associated with the changes of the studied biomarkers.

Conclusion: The ROADMAP-postCOVID-19 study offers an analysis of a large panel of biomarkers of endothelial cell activation and hypercoagulability in survivors of COVID-19. The study documents that two months after symptoms' onset, activation of endothelial cells, in vivo thrombin generation, and fibrin lysis are frequent phenomena up to two months from COVID-19 symptom onset. The data presented herein allow to propose that evaluation of blood hypercoagulability (using D-dimer for instance) and endothelial cell activation could offer the possibility of prompt identification of COVID-19 survivors at risk of post-COVID-19 vascular complications. The findings of the present study underline the need for a thorough evaluation of a potential correlation between the sustained hypercoagulability and endothelial cell activation with the symptomatology of long-COVID-19 to apply anticipated diagnostic and therapeutic strategies. The clinical relevance of the identified biomarkers of endothelial activation and hypercoagulability in the assessment of the risk of long COVID-19 must be investigated in a prospective study.

Terpos:EUSA Pharma: Honoraria, Other: Travel expenses; BMS: Honoraria; Sanofi: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Takeda: Honoraria, Other: Travel expenses, Research Funding; GSK: Honoraria, Research Funding; Amgen: Honoraria, Other: Travel expenses, Research Funding; Genesis: Honoraria, Research Funding; Novartis: Honoraria. Dimopoulos:BMS: Honoraria; Amgen: Honoraria; Beigene: Honoraria; Takeda: Honoraria; Janssen: Honoraria.

Author notes


Asterisk with author names denotes non-ASH members.

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