ABSTRACT
Background: A considerable proportion of patients do not fully recover from COVID-19 infection and report symptoms that persist beyond the initial phase of infection: This condition is defined long-COVID-19 syndrome (LCS). LCS can involve lungs as well as several extrapulmonary organs, including the cardiovascular system. The risk and 1-year burden of cardiovascular diseases (CVD) is increased in COVID-19 survivors, even in subjects at low risk of CVD. Recently, we documented that acute COVID- 19 infection induces altered platelet activation state characterized by a prothrombotic phenotype and by the formation of platelet-leukocyte aggregates (PLA), that may be involved in the pulmonary microthrombi found in autoptic specimens. No data are yet available on the contribution of platelet activation to residual pulmonary impairment and procoagulant potential in LCS patients. Purpose(s): To study platelet activation status, microvesicle (MV) profile, platelet thrombin generation capacity (pTGC) in LCS patients enrolled at 6 months after resolution of the acute phase (6mo-FU), compared to acute COVID-19 infection patients. Method(s): 6mo-FU COVID-19 patients (n=24) with established LCS were enrolled at Centro Cardiologico Monzino. Residual pulmonary impairment was assessed by Cardiopulmonary Exercise Testing (CPET) and 64-rows- CT scan evaluation. Platelet activation (P-selectin, Tissue Factor [TF] and PLA) and MV profile were assessed by flow cytometry;pTGC by calibrated automated thrombogram. 46 patients enrolled during acute COVID-19 infection and 46 healthy subjects (HS) were used for comparison. Result(s): Dispnea in LCS patients was confirmed by CPET showing compromised alveolus-capillary membrane diffusion and residual pulmonary impairment. TF+-platelet and -MV levels were 3-fold (1.5% [1.2-2.9] vs 2.4% [1.6-5.7]) and 2-fold (217/mul [137-275] vs 435/mul [275-633]) lower at 6mo-FU compared to acute phase, being comparable to HS. pTGC behaved similarly. At 6mo-FU, the MV profile, in terms of total number and cell origin, returned to physiological levels. Conversely, although lower than that measured in acute phase, a 2.5-fold higher platelet P-selectin expression (6.9% [3-13.5] vs 11.7% [5.2-18.9]) and PLA formation (35.5% [27.4- 46.8] vs 67.7% [45.7-85.3]) was observed at 6mo-FU compared to HS. Interestingly, a significant correlation between PLA formation and residual pulmonary impairment was observed (r=-0.423;p=0.02). Conclusion(s): These data strengthen the hypothesis that the presence of PLA in the bloodstream, and thus also in the pulmonary microcirculation, may contribute to support pulmonary dysfunction still observed in LCS patients.
ABSTRACT
Introduction: critically ill COVID-19 patients are known to have a coagulopathy characterized by increased levels of D-dimer (DD) associated to a thrombotic risk and a significant increase in mortality. However, it is not known whether the associated COVID-19 coagulopathy is due to a prothrombotic state or is caused by endothelial dysfunction and inflammation. Aim of our study, was to better characterize the hypercoagulability state of COVID-19 patients using Thrombin Generation analyser (ST Genesia, Diagnostica Stago, Asnieres, France). Method(s): a total of 46 non-critically ill hospitalized COVID-19 patients were compared to 19 critically ill COVID-19 patients utilizing calibrated automated thrombography and other biochemical, hematological and coagulation parameters. Result(s): critically ill patients had a significant increase in C reactive protein (CRP), interleukin-6 (IL-6), prothrombin time (PT), DD and a significant decrease in lymphocytes count. No significant differences in Thrombin Generation Test (TGT) parameters were observed between the two groups of patients with the only exception of the "Lag Time" parameter. Discussion(s): the obtained results confirmed increased levels of DD and PT in critically ill COVID-19 patients. Of note, disease severity did not cause an increase in Thrombin Generation when compared to non-critically COVID-19 patients. The significantly prolonged Lag Time in critically ill COVID-19 patients without decreased endogenous thrombin potential suggests an hypocoagulability state in these patients. The relevance of this finding is uncertain and may appear counterintuitive since these patients are expected to have a hypercoagulability status, and requires further research. Copyright © 2022 Biomedia. All rights reserved.
ABSTRACT
Background: The coagulation system showed significant variations in COVID-19 patients. These variations may parallel the disease stage of COVID-19 toward either a hyper-activation or coagulopathy syndrome. Classical clotting tests assist in exploring coagulation disorders, but they are unsuitable to examine prothrombotic conditions. In this regard, thrombin generation assay helps for a global assessment of the coagulation process, being appropriate for investigating hypercoagulable states and bleeding tendency. Aim(s): It was investigated whether thrombin generation assay reveals coagulation variations in COVID-19 patients by a care setting design. Method(s): From October to December 2020, it have been enrolled 27 and 40 patients with a confirmed COVID-19 diagnosis who were hospitalised in an Intensive Care Unit (ICU) and a Medical Ward (MW), respectively. Also, 34 healthy subjects were included in this study. Thrombin generation parameters were evaluated using a Calibrated Automated Thrombogram system. Informed consent and approval by the local medical Ethics Committee were obtained. Result(s): Lag-Time and time-to- peak found in ICU and MW patients were significantly higher than those found in healthy subjects (Kruskal-Wallis test: P < 0.0001). Endogenous-Thrombin- Potential and thrombin-peak observed in ICU and MW patients were significantly lower than those observed in healthy subjects (Kruskal-Wallis test: P < 0.0001). No statistically significant differences in all the parameters measured were observed between ICU and MW patients. Conclusion(s): Thrombin generation assay performed in this study evidenced an acquired coagulopathy in COVID-19 patients that, however, seems to be unrelated to the care setting and, in turn, to the clinical disease severity.
ABSTRACT
Background: Long-COVID- 19 syndrome (LCS) is defined as symptoms persisting beyond initial phase of infection. Among them, pulmonary fibrotic damage remains in 25-30% of COVID-19 patients at 3-6 month-follow- up. We documented that acute COVID-19 patients have massive platelet activation characterized by the formation of platelet-leukocyte aggregates (PLA), that may be involved in the pulmonary microthrombi found in autoptic specimens, and by a prothrombotic phenotype. No data are currently available on contribution of platelet activation to residual pulmonary impairment and procoagulant potential in LCS patients. Aim(s): To characterize platelet activation, microvesicle (MV) profile, platelet thrombin generation capacity (pTGC) in LCS patients at 6-month- follow- up (6mo-FU) compared to acute COVID-19 infection patients. Method(s): Twentyfour 6mo-FU COVID-19 patients with established LCS defined according to their residual pulmonary impairment assessed by Cardiopulmonary Exercise Testing (CPET) and 64-rows- CT scan evaluation were enrolled. Platelet activation (P-selectin, Tissue Factor [TF] and PLA) and MV profile were evaluated by flow cytometry;pTGC by calibrated automated thrombogram. Fortysix patients enrolled during acute COVID-19 infection and 46 healthy subjects (HS) were used for comparison. Result(s): Dispnea in LCS patients was confirmed by CPET showing compromised alveolus-capillary membrane diffusion and residual pulmonary impairment. TF+-platelet and -MV levels were 3-and 2-fold lower at 6mo-FU compared to acute phase, being comparable to HS, as well as pTGC. At 6mo-FU, the MV profile (total number and derived from different cells) returned to physiological levels. Conversely, although lower than that measured in acute phase, a 2.5-fold higher platelet P-selectin expression and PLA formation was observed at 6mo-FU compared to HS. Interestingly, a significant correlation between PLA formation and residual pulmonary impairment was observed. Conclusion(s): These data strengthen the hypothesis that the presence of PLA in the bloodstream, and thus also in the pulmonary microcirculation, may contribute to support pulmonary dysfunction still observed in LCS patients.
ABSTRACT
Background: COVID-19 has been associated with hypercoagulability, endothelial cell injury and frequent thrombotic complications resulting both from direct effects of the virus on the endothelium and from the ‘cytokine storm’ resulting from the host's immune response. Since the COVID-19 vaccines have been shown to effectively prevent symptomatic infection including hospital admissions and severe disease, the risk of COVID-19-related thrombosis should be expected to (almost) disappear in vaccinated individuals. However, some rare cases of venous thrombosis have been reported in individuals vaccinated with mRNA vaccines. Thus, there is a sharp contrast between the clinical or experimental data reported in the literature on COVID-19 and on the rare thrombotic events observed after the vaccination with these vaccines. This phenomenon raised some scepticism of even some fear about the safety of these vaccines which could compromise the adhesion of the citizens in the vaccination program. Aims: We conducted a prospective observational study, to explore the impact of vaccination with the BNT162b2 (Pfizer/BioNTech) on blood hypercoagulability and endothelial cell activation and to investigate if this is modified by the presence of active cancer. Methods: In total 229 subjects were prospectively included in the study from April to June 2021. Subjects were stratified in three predefined groups: 127 vaccinated patients with active cancer (VOnco group), 72 vaccinated health care workers (VHcw group) and 30 non vaccinated health individuals (Control group). Blood samples were obtained 2 days after the administration of the first dose of BNT162b2 vaccine and collected in Vacutainer® tubes (0.109 mol/L trisodium citrate). Platelet poor plasma (PPP) was prepared by double centrifugation at 2000 g for 20 minutes at room temperature and plasma aliquots were stored at -80°C until assayed. Samples of PPP were assessed for thrombin generation (TG) with PPP-Reagent® (Thrombogram-Thrombinoscope assay with PPP-Reagent®TF 5pM), E-selectin, D-dimers, (D-Di), Tissue Factor (TFa), procoagulant phospholipid-dependent clotting time (Procag-PPL) and von Willebrand factor (vWF), thrombomodulin (TM), tissue factor pathway inhibitor (TFPI), and platelet factor 4 (PF4). All assays were from Diagnostica Stago (France). The upper and lower normal limits (UNL and LNL) for each biomarker were calculated by the mean±2SD for the control group. Results: All vaccinated subjects showed significantly increased levels of PF4 (71% >UNL, p<0.001), D-Dimers (74% >UNL, p<0.01), vWF (60% >UNL, p<0.01), FVIII (62% >UNL, p<0.01) and shorter Procoag-PPL clotting time (96% <LNL, p<0.001), as compared to controls. Thrombin generation showed significantly higher Peak (60% >UNL, p<0.01), ETP (38% >UNL, p<0.01) and MRI (66% >UNL, p<0.01) but no differences in lag-time in vaccinated subjects as compared to the control group. Vaccinated subjects did not show any increase at the levels of TFa, TFPI, TM and E-selectin in comparison with the control group. The studied biomarkers were not significantly different between the VOnco and VHcw groups. Conclusion: The ROADMAP-COVID-19-Vaccine study shows that administration of the first dose of the BNT162b2 vaccine induced significant platelet activation documented by shorter Procoag-PPL associated with increased levels of PF4. Plasma hypercoagulability was less frequent in vaccinated individuals whereas there was no evidence of significant endothelial cells activation after vaccination. Interestingly, the presence of active cancer was not associated with an enhancement of platelet activation, hypercoagulability, or endothelial cell activation after the vaccination. Probably, the generated antibodies against the spike protein or lead to platelet activation in a FcyRIIa dependent manner that results in PF4 release. The implication of the mild inflammatory reaction triggered by the vaccination could be another possible pathway leading to platelet activation. Nevertheless, vaccination does not provoke endothelial activation even n patients with cancer. The findings of the ROADMAP-COVID-19-Vaccine study support the concept administration of mRNA based vaccines does not directly cause a systematic hypercoagulability. Disclosures: Gligorov: Roche-Genentech: Research Funding;Novartis: Research Funding;Onxeo: Research Funding;Daichi: Research Funding;MSD: Research Funding;Eisai: Research Funding;Genomic Heatlh: Research Funding;Ipsen: Research Funding;Macrogenics: Research Funding;Pfizer: Research Funding. Terpos: Novartis: Honoraria;Janssen: Consultancy, Honoraria, Research Funding;Genesis: Consultancy, Honoraria, Research Funding;Celgene: Consultancy, Honoraria, Research Funding;BMS: Honoraria;Amgen: Consultancy, Honoraria, Research Funding;Takeda: Consultancy, Honoraria, Research Funding;Sanofi: Consultancy, Honoraria, Research Funding;GSK: Honoraria, Research Funding. Dimopoulos: Amgen: Honoraria;BMS: Honoraria;Janssen: Honoraria;Beigene: Honoraria;Takeda: Honoraria.
ABSTRACT
Background Hospitalised patients with severe COVID-19 (requiring critical care level support) appear to be at increased risk of thrombosis despite standard pharmacological thromboprophylaxis. The magnitude of thrombotic risk in patients with COVID-19 of moderate severity (not requiring critical care) is less clear. The optimal approach to thromboprophylaxis (and the role of intensified thromboprophylaxis) remains to be determined. Evidence of endothelial dysfunction has been widely reported in COVID-19 (particularly in severe COVID) and this may contribute to hypercoagulability. Aim To assess differences in patterns of hypercoagulability and endothelial dysfunction between a group of patients with moderate COVID-19 and a group of age-matched hospitalized patients (SARS-CoV-2 PCR negative) receiving low molecular weight heparin (LMWH) thromboprophylaxis. Methods Blood was collected from individuals admitted to hospital with COVID-19 of moderate severity (not requiring critical care level support) and a group of age-matched patients admitted with infective/inflammatory illness (SARS-CoV-2 PCR negative). All subjects received standard-dose LMWH thromboprophylaxis, with blood drawn at 12 hours post-dose (and with measurement of anti-FXa activity levels). Circulating levels of endothelial & fibrinolytic markers including ICAM, PAI-1, VCAM, soluble thrombomodulin (sTM), and tissue plasminogen activator (tPA) were determined by ELISA. Thrombin generation (TG) in platelet-poor plasma was assessed by calibrated automated thrombography in the presence of tissue factor (Final concentration, 1pM & 5pM), thrombomodulin (TM) (Final concentration, 6.25nM), and an inhibitory anti-tissue factor pathway inhibitor antibody (anti-TFPI;Final concentration 100μg/mL). Results 14 COVID-19 positive subjects and 11 hospitalized controls were recruited. There were no differences in mean age (69.7±4.5 vs 61.6±4.7 years;p= 0.2) or mean Body mass index (25.7±1.1 vs 22.7±1.2 Kg/m2;p=0.1) between groups. No COVID-19 patient or control required critical care support. In the COVID group, radiological evidence of pneumonitis [diffuse (n=3) or peripheral infiltrates (n=7)] was present in the majority of cases. None of the COVID-19 cases were requiring supplemental oxygen at the time of recruitment. All controls were admitted with either respiratory or urinary infection [radiological evidence of pneumonia in 4/11;supplemental oxygen requirement in 2/11, (28-36% FiO2 via nasal cannula)]. Plasma levels of sTM, ICAM, PAI-1 & VCAM were similar in both groups. Levels of t-PA were significantly higher in the COVID group (8.31±4.35 vs 4.91±2.37 ng/mL;p= 0.005). Despite similar plasma anti-Xa activity in both groups (0.06 vs 0.04 IU/mL;p=0.2), mean endogenous thrombin potential (ETP) was significantly higher in the COVID group (1929±119.7 vs 1528±138.9 nM*min;p=0.02), although peak thrombin was similar (173.6±26 vs 161.5±31nM). ETP-TM ratio was similar between groups (0.3±0.1 vs 0.2±0.1;p=0.3). Despite increased ETP, the lag time to thrombin generation was significantly prolonged in the COVID group (8.3±0.6 vs 5.8±0.5 mins, p= 0.006). This pattern has previously been observed in vascular diseases associated with altered plasma tissue factor pathway inhibitor (TFPI) activity. In the presence of an anti-TFPI antibody, the difference in lagtime between groups was attenuated (4.7±0.2 vs 3.5±0.1 mins;p= 0.002) and the difference in overall thrombin generation (delta TG) between both groups became significantly increased (Fig.1). Conclusion Plasma thrombin generation is enhanced in patients with non-severe COVID-19 despite pharmacological thromboprophylaxis. Endothelial dysfunction is also observed in this group and appears to modulate parameters of plasma thrombin generation. The clinical implications of these observations are not known although clinical studies of intensified thromboprophylaxis in attenuating thrombotic risk and other complications are ongoing. Fig 1. Inhibition of TFPI activity enhances thrombin generation in COVID-19. n the presence of an inhibitory anti-TFPI antibody, peak plasma thrombin generation was enhanced in COVID-19 in contrast to that observed among SARS-CoV-2 PCR negative hospitalised patients (339.6+25.2 vs 247.4+10.1, p=0.01). [Formula presented] Disclosures: Maguire: Actelion: Research Funding;Bayer Pharma: Research Funding. Ni Ainle: Daiichi-Sankyo: Research Funding;Actelion: Research Funding;Leo Pharma: Research Funding;Bayer Pharma: Research Funding. Kevane: Leo Pharma: Research Funding.