Prevention and management of thrombosis in hospitalised patients with COVID-19 pneumonia

Global and regional burden of vaccine-induced thrombotic thrombocytopenia, 1969-2023: Comprehensive findings with critical analysis of the international pharmacovigilance database

OBJECTIVE

The scarcity of studies on vaccine-induced thrombosis and thrombocytopenia syndrome (TTS) limits the comprehensive understanding of vaccine safety on a global scale. Therefore, the objective of this study is to assess the global burden of vaccine-induced TTS, identify the vaccines most associated with it, and suggest clinical implications regarding vaccination.

METHODS

This study employed the World Health Organization international pharmacovigilance database, extracting records of vaccine-induced immune thrombotic thrombocytopenia from 1969 to 2023 (total reports, n > 130 million). Global reporting counts, reported odds ratios (ROR), and information components (IC) were calculated to identify the association between 19 vaccines and the occurrence of vaccine-induced TTS across 156 countries.

RESULTS

We identified 24 233 cases (male, n = 11 559 [47.7%]) of vaccine-induced TTS among 404 388 reports of all-cause TTS. There has been a significant increase in reports of vaccine-induced TTS events over time, with a noteworthy surge observed after 2020, attributed to cases of TTS associated with COVID-19 vaccines. Measles, mumps, and rubella (MMR) vaccines were associated with most TTS reports (ROR [95% confidence interval], 2.87 [2.75-3.00]; IC [IC0.25], 1.51 [1.43]), followed by hepatitis B (HBV, 2.23 [2.07-2.39]; 1.15 [1.03]), rotavirus diarrhea (1.95 [1.78-2.13]; 0.81 [0.53]), encephalitis (1.80 [1.50-2.16]; 0.84 [0.53]), hepatitis A (1.67 [1.50-1.86]; 0.73 [0.55]), adenovirus Type 5 vector-based (Ad5-vectored) COVID-19 (1.64 [1.59-1.68]; 0.69 [0.64]), pneumococcal (1.57 [1.49-1.66]; 0.65 [0.56]), and typhoid vaccines (1.41 [1.12-1.78]; 0.49 [0.11]). Concerning age and sex-specific risks, reports of vaccine-induced TTS were more associated with females and younger age groups. The age group between 12 and 17 years exhibited significant sex disproportion. Most of these adverse events had a short time to onset (days; mean [SD], 4.99 [40.30]) and the fatality rate was 2.20%, the highest rate observed in the age group over 65 years (3.79%) and lowest in the age group between 0 and 11 years (0.31%).

CONCLUSION

A rise in vaccine-induced TTS reports, notably MMR, HBV, and rotavirus diarrhea vaccines, was particularly related to young females. Ad5-vectored COVID-19 vaccines showed comparable or lower association with TTS compared to other vaccines. Despite the rarity of these adverse events, vigilance is essential as rare complications can be fatal, especially in older groups. Further studies with validated reporting are imperative to improve the accuracy of assessing the vaccine-induced TTS for preventive interventions and early diagnosis.

Causal Effects of COVID-19 on the Risk of Thrombosis: A Two-Sample Mendel Randomization Study

BACKGROUND

 Coronavirus disease 2019 (COVID-19) and thrombosis are linked, but the biomolecular mechanism is unclear. We aimed to investigate the causal relationship between COVID-19 and thrombotic biomarkers.

METHODS

 We used two-sample Mendelian randomization (MR) to assess the effect of COVID-19 on 20 thrombotic biomarkers. We estimated causality using inverse variance weighting with multiplicative random effect, and performed sensitivity analysis using weighted median, MR-Egger regression and MR Pleiotropy Residual Sum and Outlier (MR-PRESSO) methods. All the results were examined by false discovery rate (FDR) with the Benjamin and Hochberg method for this correction to minimize false positives. We used R language for the analysis.

RESULTS

 All COVID-19 classes showed lower levels of tissue factor pathway inhibitor (TFPI) and interleukin-1 receptor type 1 (IL-1R1). COVID-19 significantly reduced TFPI (odds ratio [OR] = 0.639, 95% confidence interval [CI]: 0.435-0.938) and IL-1R1 (OR = 0.603, 95% CI = 0.417-0.872), nearly doubling the odds. We also found that COVID-19 lowered multiple coagulation factor deficiency protein 2 and increased C-C motif chemokine 3. Hospitalized COVID-19 cases had less plasminogen activator, tissue type (tPA) and P-selectin glycoprotein ligand 1 (PSGL-1), while severe cases had higher mean platelet volume (MPV) and lower platelet count. These changes in TFPI, tPA, IL-1R1, MPV, and platelet count suggested a higher risk of thrombosis. Decreased PSGL-1 indicated a lower risk of thrombosis.

CONCLUSION

 TFPI, IL-1R, and seven other indicators provide causal clues of the pathogenesis of COVID-19 and thrombosis. This study demonstrated that COVID-19 causally influences thrombosis at the biomolecular level.

Chronic thromboembolic pulmonary hypertension is an uncommon complication of COVID-19: UK national surveillance and observational screening cohort studies

BACKGROUND

Pulmonary embolism (PE) is a well-recognised complication of coronavirus disease 2019 (COVID-19) infection, and chronic thromboembolic pulmonary disease with and without pulmonary hypertension (CTEPD/CTEPH) are potential life-limiting consequences. At present the burden of CTEPD/CTEPH is unclear and optimal and cost-effective screening strategies yet to be established.

METHODS

We evaluated the CTEPD/CTEPH referral rate to the UK national multidisciplinary team (MDT) during the 2017-2022 period to establish the national incidence of CTEPD/CTEPH potentially attributable to COVID-19-associated PE with historical comparator years. All individual cases of suspected CTEPH were reviewed by the MDT for evidence of associated COVID-19. In a separate multicentre cohort, the risk of developing CTEPH following hospitalisation with COVID-19 was calculated using simple clinical parameters at a median of 5 months post-hospital discharge according to existing risk scores using symptoms, ECG and N-terminal pro-brain natriuretic peptide.

RESULTS

By the second year of the pandemic, CTEPH diagnoses had returned to the pre-pandemic baseline (23.1 versus 27.8 cases per month; p=0.252). Of 334 confirmed CTEPD/CTEPH cases, four (1.2%) patients were identified to have CTEPH potentially associated with COVID-19 PE, and a further three (0.9%) CTEPD without PH. Of 1094 patients (mean age 58 years, 60.4% male) hospitalised with COVID-19 screened across the UK, 11 (1.0%) were at high risk of CTEPH at follow-up, none of whom had a diagnosis of CTEPH made at the national MDT.

CONCLUSION

A priori risk of developing CTEPH following COVID-19-related hospitalisation is low. Simple risk scoring is a potentially effective way of screening patients for further investigation.

Challenging the current hypothesis that thrombosis is responsible for the post-COVID-19 condition

People with the post-COVID-19 condition suffer symptoms that persist beyond 12 weeks following acute COVID-19 infection. Fatigue, shortness of breath, and cognitive dysfunction ("brain fog") are common. Scientists, clinicians, and patients debate the pathophysiology. One pathophysiological hypothesis is that prothrombotic changes associated with acute COVID-19 persist, causing clots that lead to symptoms. This theory, arising from a research team in South Africa and supported by a paper in Nature Medicine, has been widely disseminated on social media and entered the public narrative as a cause of the post-COVID-19 condition. We describe the development of this theory, examine the findings of a Cochrane review that critically appraises the "microclot" beliefs, and critically appraise the influential study relating clotting biomarkers to cognitive deficits. We conclude the inferences for the hypothesis are not based on evidence, unlicensed use of antithrombotic medication is not justified, and apheresis should not be considered outside of a well-designed clinical trial.

[COVID-19 readmissions during the first three epidemic periods in Orihuela, Spain: incidence, risk factors and letality]

OBJECTIVE

Readmission for COVID-19 is associated with high mortality, saturation of health services, and high costs. This study aimed to assess the incidence and risk factors of readmissions in COVID-19 patients in a regional hospital of Spain from February 2020 to March 2021.

METHODS

A retrospective cohort study describing the characteristics of adult patients readmitted within thirty days of discharge after being infected with SARS-CoV-2 was carried out. Readmission associated risk factors were analysed using a binary logistic regression model.

RESULTS

Of the 967 patients who survived their first COVID-19 admission, 70 (7.2%) were readmitted within thirty days. Of these, 34.3% presented pneumonia progression, 15.7% functional deterioration, and 12.9% other infections. The mortality rate during readmission was 28.6%. There were no statistically significant differences in the cumulative incidence of readmissions between the epidemic periods (p=0.241). Factors independently associated with readmission were: diabetes mellitus (aOR 1.96, 95%CI 1.07-3.57, p=0.030); acute kidney failure (aOR 2.69, 95%CI 1.43-5.07, p=0.002); not being a candidate for intensive care (aOR 7.68, 95% CI 4.28-13.80, p<0.001); and not being prescribed corticosteroids at discharge (aOR 2.15, 95% CI 1.04-4.44; p=0.039).

CONCLUSIONS

A substantial proportion of patients admitted due to COVID-19 are readmitted, and they carry a high letality. Diabetes mellitus, acute kidney failure, not being a candidate for ICU admission, and not being prescribed corticosteroids on discharge are independently associated with an increased risk of readmission.

Prior Influenza Infection Mitigates SARS-CoV-2 Disease in Syrian Hamsters

Seasonal infection rates of individual viruses are influenced by synergistic or inhibitory interactions between coincident viruses. Endemic patterns of SARS-CoV-2 and influenza infection overlap seasonally in the Northern hemisphere and may be similarly influenced. We explored the immunopathologic basis of SARS-CoV-2 and influenza A (H1N1pdm09) interactions in Syrian hamsters. H1N1 given 48 h prior to SARS-CoV-2 profoundly mitigated weight loss and lung pathology compared to SARS-CoV-2 infection alone. This was accompanied by the normalization of granulocyte dynamics and accelerated antigen-presenting populations in bronchoalveolar lavage and blood. Using nasal transcriptomics, we identified a rapid upregulation of innate and antiviral pathways induced by H1N1 by the time of SARS-CoV-2 inoculation in 48 h dual-infected animals. The animals that were infected with both viruses also showed a notable and temporary downregulation of mitochondrial and viral replication pathways. Quantitative RT-PCR confirmed a decrease in the SARS-CoV-2 viral load and lower cytokine levels in the lungs of animals infected with both viruses throughout the course of the disease. Our data confirm that H1N1 infection induces rapid and transient gene expression that is associated with the mitigation of SARS-CoV-2 pulmonary disease. These protective responses are likely to begin in the upper respiratory tract shortly after infection. On a population level, interaction between these two viruses may influence their relative seasonal infection rates.

Osteopontin: A Novel Therapeutic Target for Respiratory Diseases

Osteopontin (OPN) is a multifunctional phosphorylated protein that is involved in physiological and pathological events. Emerging evidence suggests that OPN also plays a critical role in the pathogenesis of respiratory diseases. OPN can be produced and secreted by various cell types in lungs and overexpression of OPN has been found in acute lung injury/acute respiratory distress syndrome (ALI/ARDS), pulmonary hypertension (PH), pulmonary fibrosis diseases, lung cancer, lung infection, chronic obstructive pulmonary disease (COPD), and asthma. OPN exerts diverse effects on the inflammatory response, immune cell activation, fibrosis and tissue remodeling, and tumorigenesis of these respiratory diseases, and genetic and pharmacological moudulation of OPN exerts therapeutic effects in the treatment of respiratory diseases. In this review, we summarize the recent evidence of multifaceted roles and underlying mechanisms of OPN in these respiratory diseases, and targeting OPN appears to be a potential therapeutic intervention for these diseases.

Association between antithrombotic therapy and mortality in patients hospitalized for COVID‑19

BACKGROUND

The prothrombotic state is a common abnormality in patients with coronavirus disease 2019 (COVID-19). However, there is controversy over the use of anticoagulants, especially oral anticoagulants (OAC) due to limited studies. We sought to evaluate the association between antithrombotic therapy on mortality and clinical outcomes in patients hospitalized for COVID-19 through propensity score matching (PSM) analysis.

METHODS

A retrospective cohort study was performed to include adult patients with COVID-19 in a university hospital. The primary outcome was in-hospital mortality. Secondary outcomes included intensive care unit (ICU) admission, mechanical ventilation, and acute kidney injury (AKI) during hospitalization. PSM was used as a powerful tool for matching patients' baseline characteristics. Adjusted odds ratios (aOR) with 95% confidence intervals (CI) were calculated from the models.

RESULTS

Of 4,881 COVID-19 patients during the study period, 690 (14.1%) patients received antithrombotic therapy and 4,191 (85.9%) patients were under no antithrombotic therapy. After adjustment with multivariate regression analysis, patients receiving OAC, compared with those who did not receive any antithrombotic therapy, had significantly lower odds for in-hospital mortality (aOR: 0.46. 95% CI: 0.24 to 0.87; P= 0.017). PSM analysis observed similar results (aOR: 0.35. 95% CI: 0.19 to 0.61; P< 0.001). Moreover, in critically ill patients who received mechanical ventilation, antithrombotic treatment (aOR: 0.54. 95% CI: 0.32 to 0.89; P= 0.022) was associated with reduced risk of mortality.

CONCLUSIONS

The application OACs was associated with reduced hospital mortality and mechanical ventilation requirement in COVID-19 patients. Besides, antithrombotic treatment was associated with a reduction in in-hospital mortality among critically ill COVID-19 patients who required mechanical ventilation.

COVID-19 outcomes in persons with hemophilia: results from a US-based national COVID-19 surveillance registry

BACKGROUND

Hypercoagulable state contributing to thrombotic complications worsens COVID-19 severity and outcomes, whereas anticoagulation improves outcomes by alleviating hypercoagulability.

OBJECTIVES

To examine whether hemophilia, an inherent hypocoagulable condition, offers protection against COVID-19 severity and reduces venous thromboembolism (VTE) risk in persons with hemophilia (PwH).

METHODS

A 1:3 propensity score-matched retrospective cohort study used national COVID-19 registry data (January 2020 through January 2022) to compare outcomes between 300 male PwH and 900 matched controls without hemophilia.

RESULTS

Analyses of PwH demonstrated that known risk factors (older age, heart failure, hypertension, cancer/malignancy, dementia, and renal and liver disease) contributed to severe COVID-19 and/or 30-day all-cause mortality. Non-central nervous system bleeding was an additional risk factor for poor outcomes in PwH. Odds of developing VTE with COVID-19 in PwH were associated with pre-COVID VTE diagnosis (odds ratio [OR], 51.9; 95% CI, 12.8-266; p < .001), anticoagulation therapy (OR, 12.7; 95% CI, 3.01-48.6; p < .001), and pulmonary disease (OR, 16.1; 95% CI, 10.4-25.4; p < .001). Thirty-day all-cause mortality (OR, 1.27; 95% CI, 0.75-2.11; p = .3) and VTE events (OR, 1.32; 95% CI, 0.64-2.73; p = .4) were not significantly different between the matched cohorts; however, hospitalizations (OR, 1.58; 95% CI, 1.20-2.10; p = .001) and non-central nervous system bleeding events (OR, 4.78; 95% CI, 2.98-7.48; p < .001) were increased in PwH. In multivariate analyses, hemophilia did not reduce adverse outcomes (OR, 1.32; 95% CI, 0.74-2.31; p = .2) or VTE (OR, 1.14; 95% CI, 0.44-2.67; p = .8) but increased bleeding risk (OR, 4.70; 95% CI, 2.98-7.48; p < .001).

CONCLUSION

After adjusting for patient characteristics/comorbidities, hemophilia increased bleeding risk with COVID-19 but did not protect against severe disease and VTE.

NLRP3 inflammasome and interleukin-1 contributions to COVID-19-associated coagulopathy and immunothrombosis

Immunothrombosis-immune-mediated activation of coagulation-is protective against pathogens, but excessive immunothrombosis can result in pathological thrombosis and multiorgan damage, as in severe coronavirus disease 2019 (COVID-19). The NACHT-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome produces major proinflammatory cytokines of the interleukin (IL)-1 family, IL-1β and IL-18, and induces pyroptotic cell death. Activation of the NLRP3 inflammasome pathway also promotes immunothrombotic programs including release of neutrophil extracellular traps and tissue factor by leukocytes, and prothrombotic responses by platelets and the vascular endothelium. NLRP3 inflammasome activation occurs in patients with COVID-19 pneumonia. In preclinical models, NLRP3 inflammasome pathway blockade restrains COVID-19-like hyperinflammation and pathology. Anakinra, recombinant human IL-1 receptor antagonist, showed safety and efficacy and is approved for the treatment of hypoxaemic COVID-19 patients with early signs of hyperinflammation. The non-selective NLRP3 inhibitor colchicine reduced hospitalization and death in a subgroup of COVID-19 outpatients but is not approved for the treatment of COVID-19. Additional COVID-19 trials testing NLRP3 inflammasome pathway blockers are inconclusive or ongoing. We herein outline the contribution of immunothrombosis to COVID-19-associated coagulopathy, and review preclinical and clinical evidence suggesting an engagement of the NLRP3 inflammasome pathway in the immunothrombotic pathogenesis of COVID-19. We also summarize current efforts to target the NLRP3 inflammasome pathway in COVID-19, and discuss challenges, unmet gaps, and the therapeutic potential that inflammasome-targeted strategies may provide for inflammation-driven thrombotic disorders including COVID-19.

Respiratory sequelae of COVID-19: pulmonary and extrapulmonary origins, and approaches to clinical care and rehabilitation

Although the exact prevalence of post-COVID-19 condition (also known as long COVID) is unknown, more than a third of patients with COVID-19 develop symptoms that persist for more than 3 months after SARS-CoV-2 infection. These sequelae are highly heterogeneous in nature and adversely affect multiple biological systems, although breathlessness is a frequently cited symptom. Specific pulmonary sequelae, including pulmonary fibrosis and thromboembolic disease, need careful assessment and might require particular investigations and treatments. COVID-19 outcomes in people with pre-existing respiratory conditions vary according to the nature and severity of the respiratory disease and how well it is controlled. Extrapulmonary complications such as reduced exercise tolerance and frailty might contribute to breathlessness in post-COVID-19 condition. Non-pharmacological therapeutic options, including adapted pulmonary rehabilitation programmes and physiotherapy techniques for breathing management, might help to attenuate breathlessness in people with post-COVID-19 condition. Further research is needed to understand the origins and course of respiratory symptoms and to develop effective therapeutic and rehabilitative strategies.

Pregnancy-related venous thromboembolism in Wuhan, China 2010-2022: A case-control study

OBJECTIVE

To explore the time trends and risk factors for pregnancy-related venous thromboembolism (VTE) in the Chinese population.

METHODS

A case-control study was conducted with 120 652 pregnancies between Jan 2010 and June 2022 in Wuhan, China. Medical records from pregnant patients with VTE and patients without VTE were reviewed and analyzed.

RESULTS

There were 197 cases of VTE diagnosed during pregnancy or postpartum, with an overall incidence of 1.63 per 1000 pregnancies, and the incidence rate trend of VTE was increasing year by year and then declining. The incidence of deep venous thrombosis (DVT) was 1.24 per 1000 pregnancies (76.1%). Consistent with previous studies, most VTE occurred in the puerperium (1.05 per 1000 pregnancies, 64.5%). Significant risk factors included immobility, previous VTE, systemic infection, BMI over 30, and hypertensive disorders of pregnancy.

CONCLUSION

Pregnancy-related VTE is not uncommon in China which is consistent with current foreign reports, and the change in incidence trend may be related to greater physicians' understanding of VTE and effective preventive measures after the publication of Chinese guidelines.

Treating COVID-19: Targeting the Host Response, Not the Virus

In low- and middle-income countries (LMICs), inexpensive generic drugs like statins, ACE inhibitors, and ARBs, especially if used in combination, might be the only practical way to save the lives of patients with severe COVID-19. These drugs will already be available in all countries on the first pandemic day. Because they target the host response to infection instead of the virus, they could be used to save lives during any pandemic. Observational studies show that inpatient statin treatment reduces 28–30-day mortality but randomized controlled trials have failed to show this benefit. Combination treatment has been tested for antivirals and dexamethasone but, with the exception of one observational study in Belgium, not for inexpensive generic drugs. Future pandemic research must include testing combination generic drug treatments that could be used in LMICs.

Ultrasound during the COVID-19 Pandemic: A Global Approach

SARS-CoV-2 (severe acute respiratory syndrome Coronavirus-2) rapidly spread worldwide as COVID-19 (Coronavirus disease 2019), causing a costly and deadly pandemic. Different pulmonary manifestations represent this syndrome's most common clinical manifestations, together with the cardiovascular complications frequently observed in these patients. Ultrasound (US) evaluations of the lungs, heart, and lower limbs may be helpful in the diagnosis, follow-up, and prognosis of patients with COVID-19. Moreover, POCUS (point-of-care ultrasound) protocols are particularly useful for patients admitted to intensive care units. The present review aimed to highlight the clinical conditions during the SARS-CoV-2 pandemic in which the US represents a crucial diagnostic tool.

Cardiovascular and Renal Comorbidities Included into Neural Networks Predict the Outcome in COVID-19 Patients Admitted to an Intensive Care Unit: Three-Center, Cross-Validation, Age- and Sex-Matched Study

Here, we performed a multicenter, age- and sex-matched study to compare the efficiency of various machine learning algorithms in the prediction of COVID-19 fatal outcomes and to develop sensitive, specific, and robust artificial intelligence tools for the prompt triage of patients with severe COVID-19 in the intensive care unit setting. In a challenge against other established machine learning algorithms (decision trees, random forests, extra trees, neural networks, k-nearest neighbors, and gradient boosting: XGBoost, LightGBM, and CatBoost) and multivariate logistic regression as a reference, neural networks demonstrated the highest sensitivity, sufficient specificity, and excellent robustness. Further, neural networks based on coronary artery disease/chronic heart failure, stage 3-5 chronic kidney disease, blood urea nitrogen, and C-reactive protein as the predictors exceeded 90% sensitivity and 80% specificity, reaching AUROC of 0.866 at primary cross-validation and 0.849 at secondary cross-validation on virtual samples generated by the bootstrapping procedure. These results underscore the impact of cardiovascular and renal comorbidities in the context of thrombotic complications characteristic of severe COVID-19. As aforementioned predictors can be obtained from the case histories or are inexpensive to be measured at admission to the intensive care unit, we suggest this predictor composition is useful for the triage of critically ill COVID-19 patients.

Exosomal miR-145 and miR-885 Regulate Thrombosis in COVID-19

We hypothesized that exosomal microRNAs could be implied in the pathogenesis of thromboembolic complications in coronavirus disease 2019 (COVID-19). We isolated circulating exosomes from patients with COVID-19, and then we divided our population in two arms based on the D-dimer level on hospital admission. We observed that exosomal miR-145 and miR-885 significantly correlate with D-dimer levels. Moreover, we demonstrate that human endothelial cells express the main cofactors needed for the internalization of the "Severe acute respiratory syndrome coronavirus 2" (SARS-CoV-2), including angiotensin converting enzyme 2, transmembrane protease serine 2, and CD-147. Interestingly, human endothelial cells treated with serum from COVID-19 patients release significantly less miR-145 and miR-885, exhibit increased apoptosis, and display significantly impaired angiogenetic properties compared with cells treated with non-COVID-19 serum. Taken together, our data indicate that exosomal miR-145 and miR-885 are essential in modulating thromboembolic events in COVID-19. SIGNIFICANCE STATEMENT: This work demonstrates for the first time that two specific microRNAs (namely miR-145 and miR-885) contained in circulating exosomes are functionally involved in thromboembolic events in COVID-19. These findings are especially relevant to the general audience when considering the emerging prominence of post-acute sequelae of COVID-19 systemic manifestations known as Long COVID.

Investigation of differences in coagulation characteristics between hospitalized patients with SARS-CoV-2 Alpha, Delta, and Omicron variant infection using rotational thromboelastometry (ROTEM): A single-center, retrospective, observational study

BACKGROUND

The severe acute respiratory syndrome coronavirus 2 Omicron variant has a low rate of serious illness, is highly contagious, and has spread rapidly since January 2022. The number of severe cases and deaths remains problematic. Here, we aimed to elucidate the coagulation pathology of Omicron-infected patients using rotational thromboelastometry.

METHODS

Patients with coronavirus disease 2019, hospitalized and treated from January 2021 to April 2022, were included. The Alpha-Delta and Omicron groups were defined during admission. Blood tests, clinical course, and rotational thromboelastometry measurements were compared using a propensity score-matched cohort.

RESULTS

Both groups had 21 patients each. Lactate dehydrogenase (Alpha-Delta group [interquartile range] vs. Omicron group [interquartile range]; 449 [368-518] U/L vs. 241 [196-398] U/L, p = 0.01) and ferritin (1428 [1145-3061] ng/dl vs. 481 [188-881] ng/dl, p = 0.0002) levels were significantly lower in the Omicron group. In rotational thromboelastometry, the thrombus hardness indexes FIBTEM A5 (29 [23-34] mm vs. 23 [18-28] mm, p = 0.034) and maximum clot firmness (34 [27-40] mm vs. 26 [21-33] mm, p = 0.021) were significantly lower in the Omicron group, whereas the fibrinolysis index FIBTEM LI60 (98 [92-100] % vs. 100 [100-100] %, p = 0.0082) was higher.

CONCLUSION

Severe coagulation abnormalities may be less likely in Omicron-infected patients than in those infected with the previous Alpha and Delta variants.

Long COVID: The latest manifestations, mechanisms, and potential therapeutic interventions

COVID-19 caused by SARS-CoV-2 infection affects humans not only during the acute phase of the infection, but also several weeks to 2 years after the recovery. SARS-CoV-2 infects a variety of cells in the human body, including lung cells, intestinal cells, vascular endothelial cells, olfactory epithelial cells, etc. The damages caused by the infections of these cells and enduring immune response are the basis of long COVID. Notably, the changes in gene expression caused by viral infection can also indirectly contribute to long COVID. We summarized the occurrences of both common and uncommon long COVID, including damages to lung and respiratory system, olfactory and taste deficiency, damages to myocardial, renal, muscle, and enduring inflammation. Moreover, we provided potential treatments for long COVID symptoms manifested in different organs and systems, which were based on the pathogenesis and the associations between symptoms in different organs. Importantly, we compared the differences in symptoms and frequency of long COVID caused by breakthrough infection after vaccination and infection with different variants of concern, in order to provide a comprehensive understanding of the characteristics of long COVID and propose improvement for tackling COVID-19.

Fibrinolysis in COVID-19: Impact on Clot Lysis and Modulation of Inflammation

COVID-19 is a multisystem disease caused by SARS-CoV-2 and is associated with an imbalance between the coagulation and fibrinolytic systems. Overall, hypercoagulation, hypofibrinolysis and fibrin-clot resistance to fibrinolysis predispose patients to thrombotic and thromboembolic events. In the lungs, the virus triggers alveolar and interstitial fibrin deposition, endothelial dysfunction, and pulmonary intravascular coagulation, all events intrinsically associated with the activation of inflammation and organ injury. Adding to the pathogenesis of COVID-19, there is a positive feedback loop by which local fibrin deposition in the lungs can fuel inflammation and consequently dysregulates coagulation, a process known as immunothrombosis. Therefore, fibrinolysis plays a central role in maintaining hemostasis and tissue homeostasis during COVID-19 by cleaning fibrin clots and controlling feed-forward products of coagulation. In addition, components of the fibrinolytic system have important immunomodulatory roles, as evidenced by studies showing the contribution of Plasminogen/Plasmin (Plg/Pla) to the resolution of inflammation. Herein, we review clinical evidence for the dysregulation of the fibrinolytic system and discuss its contribution to thrombosis risk and exacerbated inflammation in severe COVID-19. We also discuss the current concept of an interplay between fibrinolysis and inflammation resolution, mirroring the well-known crosstalk between inflammation and coagulation. Finally, we consider the central role of the Plg/Pla system in resolving thromboinflammation, drawing attention to the overlooked consequences of COVID-19-associated fibrinolytic abnormalities to local and systemic inflammation.

High Plasma Levels of Activated Factor VII-Antithrombin Complex Point to Increased Tissue Factor Expression in Patients with SARS-CoV-2 Pneumonia: A Potential Link with COVID-19 Prothrombotic Diathesis

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causal agent of coronavirus disease 2019 (COVID-19), in which coagulation abnormalities and endothelial dysfunction play a key pathogenic role. Tissue factor (TF) expression is triggered by endothelial dysfunction. Activated factor VII-antithrombin (FVIIa-AT) complex reflects indirectly FVIIa-TF interaction and has been proposed as a potential biomarker of prothrombotic diathesis. FVIIa-AT plasma concentration was measured in 40 patients (30 males and 10 females; 64.8 ± 12.3 years) admitted with SARS-CoV-2 pneumonia during the first pandemic wave in Italy. Two sex- and age-matched cohorts without COVID-19, with or without signs of systemic inflammation, were used to compare FVIIa-AT data. The FVIIa-AT plasma levels in COVID-19 patients were higher than those in non-COVID-19 subjects, either with or without inflammation, while no difference was observed among non-COVID-19 subjects. The association between COVID-19 and FVIIa-AT levels remained significant after adjustment for sex, age, C-reactive protein, renal function, fibrinogen, prothrombin time and activated partial thromboplastin time. Our results indicate that SARS-CoV-2 infection, at least during the first pandemic wave, was characterized by high FVIIa-AT levels, which may suggest an enhanced FVIIa-TF interaction in COVID-19, potentially consistent with SARS-CoV-2-induced endotheliopathy.

Impact of COVID-19 on the liver and on the care of patients with chronic liver disease, hepatobiliary cancer, and liver transplantation: An updated EASL position paper

The COVID-19 pandemic has presented a serious challenge to the hepatology community, particularly healthcare professionals and patients. While the rapid development of safe and effective vaccines and treatments has improved the clinical landscape, the emergence of the omicron variant has presented new challenges. Thus, it is timely that the European Association for the Study of the Liver provides a summary of the latest data on the impact of COVID-19 on the liver and issues guidance on the care of patients with chronic liver disease, hepatobiliary cancer, and previous liver transplantation, as the world continues to deal with the consequences of the COVID-19 pandemic.

Understanding COVID-19-associated coagulopathy

COVID-19-associated coagulopathy (CAC) is a life-threatening complication of SARS-CoV-2 infection. However, the underlying cellular and molecular mechanisms driving this condition are unclear. Evidence supports the concept that CAC involves complex interactions between the innate immune response, the coagulation and fibrinolytic pathways, and the vascular endothelium, resulting in a procoagulant condition. Understanding of the pathogenesis of this condition at the genomic, molecular and cellular levels is needed in order to mitigate thrombosis formation in at-risk patients. In this Perspective, we categorize our current understanding of CAC into three main pathological mechanisms: first, vascular endothelial cell dysfunction; second, a hyper-inflammatory immune response; and last, hypercoagulability. Furthermore, we pose key questions and identify research gaps that need to be addressed to better understand CAC, facilitate improved diagnostics and aid in therapeutic development. Finally, we consider the suitability of different animal models to study CAC.

Good practice statements for antithrombotic therapy in the management of COVID-19: Guidance from the SSC of the ISTH

Despite the emergence of high quality randomized trial data with the use of antithrombotic agents to reduce the risk of thromboembolism, end-organ failure, and possibly mortality in patients with coronavirus disease 2019 (COVID-19), questions still remain as to optimal patient selection for these strategies, the use of antithrombotics in outpatient settings and in-hospital settings (including critical care units), thromboprophylaxis in special patient populations, and the management of acute thrombosis in hospitalized COVID-19 patients. In October 2021, the International Society on Thrombosis and Haemostasis (ISTH) formed a multidisciplinary and international panel of content experts, two patient representatives, and a methodologist to develop recommendations on treatment with anticoagulants and antiplatelet agents for COVID-19 patients. The ISTH Guideline panel discussed additional topics to be well suited to a non-Grading of Recommendations Assessment, Development, and Evaluation (GRADE) for Good Practice Statements (GPS) to support good clinical care in the antithrombotic management of COVID-19 patients in various clinical settings. The GPS panel agreed on 17 GPS: 3 in the outpatient (pre-hospital) setting, 12 in the hospital setting both in non-critical care (ward) as well as intensive care unit settings, and 2 in the immediate post-hospital discharge setting based on limited evidence or expert opinion that supports net clinical benefit in enacting the statements provided. The antithrombotic therapies discussed in these GPS should be available in low- and middle-income countries.

Soluble Urokinase Plasminogen Activator Receptor and Venous Thromboembolism in COVID-19

Background Venous thromboembolism (VTE) contributes significantly to COVID-19 morbidity and mortality. The urokinase receptor system is involved in the regulation of coagulation. Levels of soluble urokinase plasminogen activator receptor (suPAR) reflect hyperinflammation and are strongly predictive of outcomes in COVID-19. Whether suPAR levels identify patients with COVID-19 at risk for VTE is unclear. Methods and Results We leveraged a multinational observational study of patients hospitalized for COVID-19 with suPAR and D-dimer levels measured on admission. In 1960 patients (mean age, 58 years; 57% men; 20% Black race), we assessed the association between suPAR and incident VTE (defined as pulmonary embolism or deep vein thrombosis) using logistic regression and Fine-Gray modeling, accounting for the competing risk of death. VTE occurred in 163 (8%) patients and was associated with higher suPAR and D-dimer levels. There was a positive association between suPAR and D-dimer (β=7.34; P=0.002). Adjusted for clinical covariables, including D-dimer, the odds of VTE were 168% higher comparing the third with first suPAR tertiles (adjusted odds ratio, 2.68 [95% CI, 1.51-4.75]; P<0.001). Findings were consistent when stratified by D-dimer levels and in survival analysis accounting for death as a competing risk. On the basis of predicted probabilities from random forest, a decision tree found the combined D-dimer <1 mg/L and suPAR <11 ng/mL cutoffs, identifying 41% of patients with only 3.6% VTE probability. Conclusions Higher suPAR was associated with incident VTE independently of D-dimer in patients hospitalized for COVID-19. Combining suPAR and D-dimer identified patients at low VTE risk. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT04818866.

Coagulopathy in COVID-19 and anticoagulation clinical trials

Severe acute respiratory disease coronavirus 2 (SARS-COV-2) first emerged in Wuhan, China, in December 2019 and has caused a global pandemic of a scale unprecedented in the modern era. People infected with SARS-CoV-2 can be asymptomatic, moderate symptomatic or develop severe COVID-19. Other than the typical acute respiratory distress syndrome (ARDS), patients with moderate or severe COVID-19 also develop a distinctive systemic coagulopathy, known as COVID-19-associated coagulopathy (CAC), which is different from sepsis-related forms of disseminated intravascular coagulation (DIC). Endotheliopathy or endotheliitis are other unique features of CAC. The endothelial cell perturbation can further increase the risk of thrombotic events in COVID-19 patients. In this review, we will summarize the current knowledge on COVID-19 coagulopathy and the possible mechanisms for the condition. We also discuss the results of clinical trials testing methods for mitigating thrombosis events in COVID-19 patients.

The potential role of ischaemia-reperfusion injury in chronic, relapsing diseases such as rheumatoid arthritis, Long COVID, and ME/CFS: evidence, mechanisms, and therapeutic implications

Ischaemia-reperfusion (I-R) injury, initiated via bursts of reactive oxygen species produced during the reoxygenation phase following hypoxia, is well known in a variety of acute circumstances. We argue here that I-R injury also underpins elements of the pathology of a variety of chronic, inflammatory diseases, including rheumatoid arthritis, ME/CFS and, our chief focus and most proximally, Long COVID. Ischaemia may be initiated via fibrin amyloid microclot blockage of capillaries, for instance as exercise is started; reperfusion is a necessary corollary when it finishes. We rehearse the mechanistic evidence for these occurrences here, in terms of their manifestation as oxidative stress, hyperinflammation, mast cell activation, the production of marker metabolites and related activities. Such microclot-based phenomena can explain both the breathlessness/fatigue and the post-exertional malaise that may be observed in these conditions, as well as many other observables. The recognition of these processes implies, mechanistically, that therapeutic benefit is potentially to be had from antioxidants, from anti-inflammatories, from iron chelators, and via suitable, safe fibrinolytics, and/or anti-clotting agents. We review the considerable existing evidence that is consistent with this, and with the biochemical mechanisms involved.

Prognostic Value of Mid-Region Proadrenomedullin and In Vitro Interferon Gamma Production for In-Hospital Mortality in Patients with COVID-19 Pneumonia and Respiratory Failure: An Observational Prospective Study

Coagulopathy and immune dysregulation have been identified as important causes of adverse outcomes in coronavirus disease (COVID-19). Mid-region proadrenomedullin (MR-proADM) is associated with endothelial damage and has recently been proposed as a prognostic factor in COVID-19. In non-COVID-19 immunocompromised patients, low in vitro interferon gamma (IFNγ) production correlates with infection risk and mortality. This prospective, monocentric, observational study included adult patients consecutively admitted with radiologic evidence of COVID-19 pneumonia and respiratory failure. MR-proADM and in vitro IFNγ production were measured at T0 (day 1 from admission) and T1 (day 7 from enrollment). One hundred patients were enrolled. Thirty-six percent were females, median age 65 (Q1−Q3 54.5−75) years, and 58% had ≥1 comorbidity. Only 16 patients had received COVID-19 vaccination before hospitalization. At admission, the median PaO2:FiO2 ratio was 241 (157−309) mmHg. In-hospital mortality was 13%. MR-proADM levels differed significantly between deceased and survivors both at T0 (1.41 (1.12−1.77) nmol/L vs. 0.79 (0.63−1.03) nmol/L, p < 0.001) and T1 (1.67 (1.08−1.96) nmol/L vs. 0.66 (0.53−0.95) nmol/L, p < 0.001). In vitro IFNγ production at T0 and T1 did not vary between groups. When only the subset of non-vaccinated patients was considered, both biomarkers at T1 resulted significantly associated with in-hospital mortality. AUROC for MR-proADM at T0 to predict in-hospital mortality was 0.87 (95%CI 0.79−0.94), with the best cut-off point at 1.04 nmol/L (92% sensitivity, 75% specificity and 98% negative predictive value). In patients with COVID-19 pneumonia and different degrees of respiratory failure, MR-proADM at admission and during hospitalization resulted strongly associated with in-hospital mortality. Low in vitro IFNγ production after the first week of hospitalization was associated with mortality in non-vaccinated patients possibly identifying the subgroup characterized by a higher degree of immune suppression.

Efficacy and safety of intensified versus standard prophylactic anticoagulation therapy in patients with Covid-19: a systematic review and meta-analysis

Background

Randomized controlled trials (RCTs) have reported inconsistent effects from intensified anticoagulation on clinical outcomes in coronavirus disease 2019 (COVID-19). We performed an aggregate data meta-analysis from available trials to quantify effect on nonfatal and fatal outcomes and identify subgroups who may benefit.

Methods

We searched multiple databases for RCTs comparing intensified (intermediate or therapeutic dose) vs prophylactic anticoagulation in adults with laboratory-confirmed COVID-19 through 19 January 2022. We used random-effects meta-analysis to estimate pooled risk ratios for mortality, thrombotic, and bleeding events (at end of follow-up or discharge) and performed subgroup analysis for clinical setting and dose of intensified anticoagulation.

Results

Eleven RCTs were included (N = 5873). Intensified vs prophylactic anticoagulation was not associated with a mortality reduction up to 45 days (risk ratio [RR], 0.93 [95% confidence interval {CI}, .79–1.10]). There was a possible signal of mortality reduction for non–intensive care unit (ICU) patients, although with low precision and high heterogeneity (5 studies; RR, 0.84 [95% CI, .49–1.44]; I² = 75%). Risk of venous thromboembolism was reduced (RR, 0.53 [95% CI, .41–.69]; I² = 0%), with effect driven by therapeutic rather than intermediate dosing (interaction P = .04). Major bleeding was increased with intensified anticoagulation (RR, 1.73 [95% CI, 1.17–2.56]) with no interaction for dosing and clinical setting.

Conclusions

Intensified anticoagulation has no effect on mortality among hospitalized adults with COVID-19 and is associated with increased bleeding risk. The observed reduction in venous thromboembolism risk and trend toward reduced mortality in non-ICU settings requires exploration in additional RCTs.

Clinical Trials Registration. CRD42021273449 (PROSPERO).

Screening the Potential Biomarkers of COVID-19-Related Thrombosis Through Bioinformatics Analysis

A high proportion of critically ill patients with coronavirus disease 2019 (COVID-19) experience thrombosis, and there is a strong correlation between anticoagulant therapy and the COVID-19 survival rate, indicating that common COVID-19 and thrombosis targets have potential therapeutic value for severe COVID-19.Gene expression profiling data were downloaded from Gene Expression Omnibus (GEO), and common differentially expressed genes (co-DEGs) were identified. The potential biological functions of these co-DEGs were explored by functional enrichment analysis, and protein–protein interaction (PPI) networks were constructed to elucidate the molecular mechanisms of the co-DEGs. Finally, hub genes in the co-DEG network were identified, and correlation analysis was performed.We identified 8320 upregulated genes and 7651 downregulated genes from blood samples of COVID-19 patients and 368 upregulated genes and 240 downregulated genes from blood samples of thrombosis patients. The enriched cellular component terms were mainly related to cytosolic ribosomes and ribosomal subunits. The enriched molecular function terms were mainly related to structural constituents of ribosomes and electron transfer activity. Construction of the PPI network and identification of hub genes ultimately confirmed that RPS7, IGF1R, DICER1, ERH, MCTS1, and TNPO1 were jointly upregulated hub genes, and FLNA and PXN were jointly downregulated hub genes.The identification of novel potential biomarkers provides new options for treating COVID-19-related thrombosis and reducing the rate of severe COVID-19.

Efficacy and safety of intensified versus standard prophylactic anticoagulation therapy in patients with Covid-19: a systematic review and meta-analysis

Background

Randomised controlled trials (RCTs) have reported inconsistent effects from intensified anticoagulation on clinical outcomes in Covid-19. We performed an aggregate data meta-analysis from available trials to quantify effect on non-fatal and fatal outcomes and identify subgroups who may benefit.

Methods

We searched multiple databases for RCTs comparing intensified (intermediate or therapeutic dose) versus standard prophylactic dose anticoagulation in adults with laboratory-confirmed Covid-19 through 19 January 2022. The primary efficacy outcome was all-cause mortality at end of follow-up or discharge. We used random effects meta-analysis to estimate pooled risk ratios for mortality, thrombotic, and bleeding events, and performed subgroup analysis for clinical setting and dose of intensified anticoagulation.

Results

Eleven RCTs were included (n = 5873). Intensified anticoagulation was not associated with a reduction in mortality for up to 45 days compared with prophylactic anticoagulation: 17.5% (501/2861) died in the intensified anticoagulation group and 18.8% (513/2734) died in the prophylactic anticoagulation group, relative risk (RR) 0.93; 95%CI, 0.79 - 1.10. On subgroup analysis, there was a possible signal of mortality reduction for inpatients admitted to general wards, although with low precision and high heterogeneity (5 studies; RR 0.84; 95% CI, 0.49 - 1.44; I 2 = 75%) and not significantly different to studies performed in the ICU (interaction P = 0.51). Risk of venous thromboembolism was reduced with intensified anticoagulation compared with prophylaxis (8 studies; RR 0.53, 95%CI 0.41 - 0.69; I 2 = 0%). This effect was driven by therapeutic rather than intermediate dosing on subgroup analysis (interaction P =0.04). Major bleeding was increased with use of intensified anticoagulation (RR 1.73, 95% CI 1.17 - 2.56) with no interaction for dosing and clinical setting.

Conclusion

Intensified anticoagulation has no effect on short term mortality among hospitalised adults with Covid-19 and is associated with increased risk of bleeding. The observed reduction in venous thromboembolism risk and trend towards reduced mortality in non-ICU hospitalised patients requires exploration in additional RCTs.

Summary

In this aggregate data meta-analysis, use of intensified anticoagulation had no effect on short term mortality among hospitalised adults with Covid-19 and was associated with increased risk of bleeding.

Adrenomedullin Therapy in Moderate to Severe COVID-19

The 2019 coronavirus (COVID-19) pandemic is still in progress, and a significant number of patients have presented with severe illness. Recently introduced vaccines, antiviral medicines, and antibody formulations can suppress COVID-19 symptoms and decrease the number of patients exhibiting severe disease. However, complete avoidance of severe COVID-19 has not been achieved, and more importantly, there are insufficient methods to treat it. Adrenomedullin (AM) is an endogenous peptide that maintains vascular tone and endothelial barrier function. The AM plasma level is markedly increased during severe inflammatory disorders, such as sepsis, pneumonia, and COVID-19, and is associated with the severity of inflammation and its prognosis. In this study, exogenous AM administration reduced inflammation and related organ damage in rodent models. The results of this study strongly suggest that AM could be an alternative therapy in severe inflammation disorders, including COVID-19. We have previously developed an AM formulation to treat inflammatory bowel disease and are currently conducting an investigator-initiated phase 2a trial for moderate to severe COVID-19 using the same formulation. This review presents the basal AM information and the most recent translational AM/COVID-19 study.

A central role for amyloid fibrin microclots in long COVID/PASC: origins and therapeutic implications

Post-acute sequelae of COVID (PASC), usually referred to as 'Long COVID' (a phenotype of COVID-19), is a relatively frequent consequence of SARS-CoV-2 infection, in which symptoms such as breathlessness, fatigue, 'brain fog', tissue damage, inflammation, and coagulopathies (dysfunctions of the blood coagulation system) persist long after the initial infection. It bears similarities to other post-viral syndromes, and to myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Many regulatory health bodies still do not recognize this syndrome as a separate disease entity, and refer to it under the broad terminology of 'COVID', although its demographics are quite different from those of acute COVID-19. A few years ago, we discovered that fibrinogen in blood can clot into an anomalous 'amyloid' form of fibrin that (like other β-rich amyloids and prions) is relatively resistant to proteolysis (fibrinolysis). The result, as is strongly manifested in platelet-poor plasma (PPP) of individuals with Long COVID, is extensive fibrin amyloid microclots that can persist, can entrap other proteins, and that may lead to the production of various autoantibodies. These microclots are more-or-less easily measured in PPP with the stain thioflavin T and a simple fluorescence microscope. Although the symptoms of Long COVID are multifarious, we here argue that the ability of these fibrin amyloid microclots (fibrinaloids) to block up capillaries, and thus to limit the passage of red blood cells and hence O2 exchange, can actually underpin the majority of these symptoms. Consistent with this, in a preliminary report, it has been shown that suitable and closely monitored 'triple' anticoagulant therapy that leads to the removal of the microclots also removes the other symptoms. Fibrin amyloid microclots represent a novel and potentially important target for both the understanding and treatment of Long COVID and related disorders.