COVID-19 and Its Implications for Thrombosis and Anticoagulation

The impact of hypertension on clinical manifestations of Omicron variant BA.1 infection in adult patients

COVID-19 caused by Omicron BA.1 has resulted in a global humanitarian crisis. In this COVID-19 pandemic era, hypertension has been receiving increased attention. Omicron BA.1 infection combined with hypertension created a serious public health problem and complicated the treatment and prognosis of COVID-19. The aim of our study was to assess the implications of hypertension for the clinical manifestations of adult patients (APs) infected with Omicron BA.1. This single-center retrospective cohort study enrolled consecutive COVID-19 APs, who were admitted to Tianjin First Central Hospital from 01 August 2022 to 30 November 2022. All included APs were divided into two groups: hypertension and non-hypertension group. The APs' baseline demographic, laboratory, clinical, and radiological characteristics were collected and analyzed. Of 512 APs admitted with PCR proven COVID-19, 161 (31.45%) APs had comorbid hypertension. Hypertension APs have older age, higher body mass index, lower Ct-values of the viral target genes at admission, and longer hospital stay than non-hypertension APs. Furthermore, hypertension aggravates the clinical classification, impairs liver, kidney, and myocardium function, and abnormalizes the coagulation system in Omicron BA.1- infected APs. Moreover, hypertension elevates inflammation levels and lung lesion involvement while weakened virus-specific IgM level in APs with Omicron BA.1 infection. Hypertension APs tend to have worse clinical conditions at baseline than those non-hypertension APs. This study indicates that hypertension is a contributor to the poor clinical manifestations of Omicron BA.1-infected APs and supports that steps to control blood pressure should be a vital consideration for reducing the burden of Omicron BA.1 infection in hypertension individuals.

IMPORTANCE

This study provided inclusive insight regarding the relationship between hypertension and Omicron BA.1 infection and supported that hypertension was an adverse factor for COVID-19 APs. In conclusion, this study showed that hypertension was considered to be associated with severe conditions, and a contributor to poor clinical manifestations. Proper medical management of hypertension patients is an imperative step in mitigating the severity of Omicron BA.1 variant infection.

Epidemiology, pathogenesis, and management of Coronavirus disease 2019-associated stroke

The Coronavirus disease 2019 (COVID-19) epidemic has triggered a huge impact on healthcare, socioeconomics, and other aspects of the world over the past three years. An increasing number of studies have identified a complex relationship between COVID-19 and stroke, although active measures are being implemented to prevent disease transmission. Severe COVID-19 may be associated with an increased risk of stroke and increase the rates of disability and mortality, posing a serious challenge to acute stroke diagnosis, treatment, and care. This review aims to provide an update on the influence of COVID-19 itself or vaccines on stroke, including arterial stroke (ischemic stroke and hemorrhagic stroke) and venous stroke (cerebral venous thrombosis). Additionally, the neurovascular mechanisms involved in SARS-CoV-2 infection and the clinical characteristics of stroke in the COVID-19 setting are presented. Evidence on vaccinations, potential therapeutic approaches, and effective strategies for stroke management has been highlighted.

A predictive model for disease severity among COVID-19 elderly patients based on IgG subtypes and machine learning

Objective

Due to the increased likelihood of progression of severe pneumonia, the mortality rate of the elderly infected with coronavirus disease 2019 (COVID-19) is high. However, there is a lack of models based on immunoglobulin G (IgG) subtypes to forecast the severity of COVID-19 in elderly individuals. The objective of this study was to create and verify a new algorithm for distinguishing elderly individuals with severe COVID-19.

Methods

In this study, laboratory data were gathered from 103 individuals who had confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection using a retrospective analysis. These individuals were split into training (80%) and testing cohort (20%) by using random allocation. Furthermore, 22 COVID-19 elderly patients from the other two centers were divided into an external validation cohort. Differential indicators were analyzed through univariate analysis, and variable selection was performed using least absolute shrinkage and selection operator (LASSO) regression. The severity of elderly patients with COVID-19 was predicted using a combination of five machine learning algorithms. Area under the curve (AUC) was utilized to evaluate the performance of these models. Calibration curves, decision curves analysis (DCA), and Shapley additive explanations (SHAP) plots were utilized to interpret and evaluate the model.

Results

The logistic regression model was chosen as the best machine learning model with four principal variables that could predict the probability of COVID-19 severity. In the training cohort, the model achieved an AUC of 0.889, while in the testing cohort, it obtained an AUC of 0.824. The calibration curve demonstrated excellent consistency between actual and predicted probabilities. According to the DCA curve, it was evident that the model provided significant clinical advantages. Moreover, the model performed effectively in an external validation group (AUC=0.74).

Conclusion

The present study developed a model that can distinguish between severe and non-severe patients of COVID-19 in the elderly, which might assist clinical doctors in evaluating the severity of COVID-19 and reducing the bad outcomes of elderly patients.

Lung abscess following ventilator-associated pneumonia during COVID-19: a retrospective multicenter cohort study

BACKGROUND

Patients undergoing mechanical ventilation (MV) for COVID-19 exhibit an increased risk of ventilator-associated pneumonia (VAP). The occurrence of lung abscesses following VAP in these patients has been poorly studied. We aimed to describe the incidence, characteristics, risk factors and prognosis of lung abscesses complicating VAP after COVID-19.

METHODS

We conducted an observational, retrospective study in three French intensive care units. Patients admitted for acute respiratory failure with a confirmed SARS-CoV-2 PCR and requiring MV for more than 48 h were included.

RESULTS

Among the 507 patients included, 326 (64%) had a documented VAP. Of these, 23 (7%) developed a lung abscess. Enterobacterales (15/23, 65%) were the main documentation, followed by non-fermenting Gram-negative bacilli (10/23, 43%) and Gram-positive cocci (8/23, 35%). Lung abscesses were mainly plurimicrobial (15/23, 65%). In multivariate analysis, a plurimicrobial 1st VAP episode (OR (95% CI) 2.93 (1.16-7.51); p = 0.02) and the use of hydrocortisone (OR (95% CI) 4.86 (1.95-12.1); p = 0.001) were associated with lung abscess development. Intensive care unit (ICU) mortality of patients with lung abscesses reached 52%, but was not significantly higher than for patients with VAP but no lung abscess. Patients with lung abscesses had reduced ventilator-free days at day 60, a longer duration of MV and ICU stay than patients with VAP but no lung abscess (respectively, 0 (0-3) vs. 16 (0-42) days; p < 0.001, 49 (32-73) vs. 25 (11-41) days; p < 0.001, 52 (36-77) vs. 28 (16-47) days; p < 0.001).

CONCLUSIONS

Lung abscessing pneumonia is not uncommon among COVID-19 patients developing VAP. A plurimicrobial first VAP episode and the use of hydrocortisone are independently associated with this complication. In COVID-19 patients with persistent VAP, a chest CT scan investigating the evolution toward lung abscess should be considered.

Anticoagulant therapy in COVID-19: A narrative review

Coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), can manifest itself in several ways, including coagulopathy and thrombosis. These complications can be the first and sometimes only manifestations of SARS-CoV-2 infection and can occur early or late in the course of the disease. However, these symptoms are more prevalent in hospitalized patients with venous thromboembolism, particularly those admitted to intensive care units. Moreover, various forms of arterial and venous thrombosis, or micro- or macro-vasculature embolisms, have been reported during the current pandemic. They have led to harmful consequences, such as neurological and cardiac events, nearly all resulting from the hypercoagulable state caused by this viral infection. The severe hypercoagulability observed in patients with COVID-19 accounts for most cases of the disease that become critical. Therefore, anticoagulants seem to be one of the most vital therapeutics for treating this potentially life-threatening condition. In the current paper, we present a thorough review of the pathophysiology of COVID-19-induced hypercoagulable state and the use of anticoagulants to treat SARS-CoV-2 infections in different patient groups, as well as their pros and cons.

Metabolic alterations upon SARS-CoV-2 infection and potential therapeutic targets against coronavirus infection

The coronavirus disease 2019 (COVID-19) caused by coronavirus SARS-CoV-2 infection has become a global pandemic due to the high viral transmissibility and pathogenesis, bringing enormous burden to our society. Most patients infected by SARS-CoV-2 are asymptomatic or have mild symptoms. Although only a small proportion of patients progressed to severe COVID-19 with symptoms including acute respiratory distress syndrome (ARDS), disseminated coagulopathy, and cardiovascular disorders, severe COVID-19 is accompanied by high mortality rates with near 7 million deaths. Nowadays, effective therapeutic patterns for severe COVID-19 are still lacking. It has been extensively reported that host metabolism plays essential roles in various physiological processes during virus infection. Many viruses manipulate host metabolism to avoid immunity, facilitate their own replication, or to initiate pathological response. Targeting the interaction between SARS-CoV-2 and host metabolism holds promise for developing therapeutic strategies. In this review, we summarize and discuss recent studies dedicated to uncovering the role of host metabolism during the life cycle of SARS-CoV-2 in aspects of entry, replication, assembly, and pathogenesis with an emphasis on glucose metabolism and lipid metabolism. Microbiota and long COVID-19 are also discussed. Ultimately, we recapitulate metabolism-modulating drugs repurposed for COVID-19 including statins, ASM inhibitors, NSAIDs, Montelukast, omega-3 fatty acids, 2-DG, and metformin.

Venous thromboembolism in viral diseases: A comprehensive literature review

Venous thromboembolism (VTE) is known to be a common respiratory and/or cardiovascular complication in hospitalized patients with viral infections. Numerous studies have proven human immunodeficiency virus infection to be a prothrombotic condition. An elevated VTE risk has been observed in critically ill H1N1 influenza patients. VTE risk is remarkably higher in patients infected with the Hepatitis C virus in contrast to uninfected subjects. The elevation of D-dimer levels supported the association between Chikungunya and the Zika virus and the rise of clinical VTE risk. Varicella-zoster virus is a risk factor for both cellulitis and the consequent invasive bacterial disease which may take part in thrombotic initiation. Eventually, hospitalized patients infected with the coronavirus disease of 2019 (COVID-19), the cause of the ongoing worldwide pandemic, could mainly suffer from an anomalous risk of coagulation activation with enhanced venous thrombosis events and poor quality clinical course. Although the risk of VTE in nonhospitalized COVID-19 patients is not known yet, there are a large number of guidelines and studies on thromboprophylaxis administration for COVID-19 cases. This study aims to take a detailed look at the effect of viral diseases on VTE, the epidemiology of VTE in viral diseases, and the diagnosis and treatment of VTE.

Neutrophil extracellular traps are increased after extracorporeal membrane oxygenation support initiation and present in thrombus: A preclinical study using sheep as an animal model

BACKGROUND

The balance between thrombosis and hemostasis is a difficult issue during extracorporeal membrane oxygenation (ECMO) support. The pathogenesis leading to thrombotic complications during ECMO support is not well understood. Neutrophil extracellular traps (NETs) were reported to participate in thrombosis and have a key role in inflammation. This study aimed to explore the role of NETs in thrombosis during ECMO support and investigate NETs as a predictive biomarker for thrombotic complications during ECMO assistance.

METHODS

Ten ovine models of ECMO support were established. Animals were then randomly divided into 2 groups (5 sheep/group): venoarterial (VA) ECMO group and venovenous (VV) ECMO group. The venous blood samples were collected at different time points. Markers of NETs were detected in plasma, neutrophils, and thrombi from the vessels and membrane. Moreover, circulating NETs levels in 8 adults treated in the intensive care unit (ICU) who received VA-ECMO and 8 healthy controls were detected; patient survival was also recorded.

RESULTS

In vivo study showed that neutrophils and NETs markers (dsDNA and citH3) levels were significantly elevated 6 h after ECMO compared to baseline. Isolated neutrophils from fresh blood at 6 h could release more NETs. dsDNA and citH3 levels were significantly higher in the VA mode than in the VV mode. NETs were found in thrombi from the vessel and membrane. Clinical data further revealed that dsDNA, citH3, and nucleosomes were higher in patients who received ECMO than in healthy controls.

CONCLUSIONS

These data suggest NETs might be associated with thrombus during ECMO support, especially in the VA mode. These findings provide new insight into preventing thrombotic complications by targeting NETs. Also, NETs may potentially become an early warning biomarker for thrombosis under ECMO assistance.

Subcutaneous Enoxaparin for Systemic Anticoagulation of COVID-19 Patients During Extracorporeal Life Support

Background

Extracorporeal membrane oxygenation, with an inherent requirement for anticoagulation to avoid circuit thrombosis, is a key element in the treatment of respiratory failure associated with COVID-19. Anticoagulation remains challenging, the standard of care being intravenous continuous administration of unfractionated heparin. Yet regimens vary. Some intensive care units in our center have successfully used enoxaparin subcutaneously in recent years and throughout the pandemic.

Methods

We retrospectively analyzed adult COVID-19 patients with respiratory failure who had been systemically anticoagulated using either enoxaparin or unfractionated heparin. The choice of anticoagulant therapy was based on the standard of the intensive care unit. Defined thromboembolic and hemorrhagic events were analyzed as study endpoints.

Results

Of 98 patients, 62 had received enoxaparin and 36 unfractionated heparin. All hazard ratios for the thromboembolic (3.43; 95% CI: 1.08–10.87; p = 0.04), hemorrhagic (2.58; 95% CI: 1.03–6.48; p = 0.04), and composite (2.86; 95% CI: 1.41–5.92; p = 0.007) endpoints favored enoxaparin, whose efficient administration was verified by peak levels of anti-factor Xa (median: 0.45 IU ml⁻¹; IQR: 0.38; 0.56). Activated partial thromboplastin time as well as thrombin time differed significantly (both p<0.001) between groups mirroring the effect of unfractionated heparin.

Conclusions

This study demonstrates the successful use of subcutaneous enoxaparin for systemic anticoagulation in patients with COVID-19 during extracorporeal membrane oxygenation. Our findings are to be confirmed by future prospective, randomized, controlled trials.

The Difference Coagulopathy Factor and Interleukin-6 between Survival and Non-survival Patients COVID-19

Background: Coronavirus disease 2019 (COVID-19) was caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) virus. SARS-CoV-2 infection can result in coagulopathy and an increase in inflammatory responses. Numerous studies have shown a significant difference in interleukin levels and coagulopathy parameters such as platelet, aPTT, PT, and D- dimer between survivor and non-survivor patient COVID-19. Aim: The purpose of this study is to compare the age, coagulopathy characteristics, and interleukin-6 levels of non-survival versus survival patients. COVID-19. Methods: A cross-sectional retrospective study was conducted on COVID-19 patients. The diagnostic criteria are based on the Indonesian Ministry of Health's recommendations. The patient's blood was analyzed in the hospital's central laboratory. Patients are classified into two groups based on their likelihood of surviving: non-survival and survival. SPSS version 22 was used to analyze the data. Results: A total of 557 patients with COVID-19 were included in this study. Patients were categorized into 146 non-survival and 411 survival subgroups. There was a significant difference in the mean age, coagulopathy parameters, and interleukin-6 expect platelets between non-survival and survival outcomes in COVID-19 patients. Conclusion: This study demonstrated a statistically significant difference in PT, aPTT, D-Dimer, and interleukin-6 levels between the non-survival and survival groups of COVID-19.

NO in Viral Infections: Role and Development of Antiviral Therapies

Nitric oxide is a ubiquitous signaling radical that influences critical body functions. Its importance in the cardiovascular system and the innate immune response to bacterial and viral infections has been extensively investigated. The overproduction of NO is an early component of viral infections, including those affecting the respiratory tract. The production of high levels of NO is due to the overexpression of NO biosynthesis by inducible NO synthase (iNOS), which is involved in viral clearance. The development of NO-based antiviral therapies, particularly gaseous NO inhalation and NO-donors, has proven to be an excellent antiviral therapeutic strategy. The aim of this review is to systematically examine the multiple research studies that have been carried out to elucidate the role of NO in viral infections and to comprehensively describe the NO-based antiviral strategies that have been developed thus far. Particular attention has been paid to the potential mechanisms of NO and its clinical use in the prevention and therapy of COVID-19.

Antibody-mediated procoagulant platelet formation in COVID-19 is AKT dependent

BACKGROUND

Thromboembolic events are frequently reported in patients infected with the SARS-CoV-2. Recently, we observed that platelets from patients with severe COVID-19 infection express procoagulant phenotype. The molecular mechanisms that induce the generation of procoagulant platelets in COVID-19 patients are not completely understood.

OBJECTIVES

In this study, we investigated the role of AKT (also known as Protein Kinase B), which is the major downstream effector of PI3K (phosphoinositid-3-kinase) (PI3K/AKT) signaling pathway in platelets from patients with COVID-19.

PATIENTS AND METHODS

Platelets, Sera and IgG from COVID-19 patients who were admitted to the intensive care unit (ICU) were analyzed by flow cytometry as well as western blot and adhesion assays.

RESULTS

Platelets from COVID-19 patients showed significantly higher levels of phosphorylated AKT, which was correlated with CD62p expression and phosphatidylserine (PS) externalization. In addition, healthy platelets incubated with sera or IgGs from ICU COVID-19 patients induced phosphorylation of PI3K and AKT and were dependent on Fc-gamma-RIIA (FcγRIIA). In contrast, ICU COVID-19 sera mediated generation of procoagulant platelets was not dependent on GPIIb/IIIa. Interestingly, the inhibition of phosphorylation of both proteins AKT and PI3K prevented the generation of procoagulant platelets.

CONCLUSIONS

Our study shows that pAKT/AKT signaling pathway is associated with the formation of procoagulant platelets in severe COVID-19 patients without integrin GPIIb/IIIa engagement. The inhibition of PI3K/AKT phosphorylation might represent a promising strategy to reduce the risk for thrombosis in patients with severe COVID-19.

PICO Questions and DELPHI Methodology for the Management of Venous Thromboembolism Associated with COVID-19

Patients with coronavirus disease 2019 (COVID-19) have a higher risk of venous thromboembolic disease (VTE) than patients with other infectious or inflammatory diseases, both as macrothrombosis (pulmonar embolism and deep vein thrombosis) or microthrombosis. However, the use of anticoagulation in this scenario remains controversial. This is a project that used DELPHI methodology to answer PICO questions related to anticoagulation in patients with COVID-19. The objective was to reach a consensus among multidisciplinary VTE experts providing answers to those PICO questions. Seven PICO questions regarding patients with COVID-19 responded with a broad consensus: 1. It is recommended to avoid pharmacological thromboprophylaxis in most COVID-19 patients not requiring hospital admission; 2. In most hospitalized patients for COVID-19 who are receiving oral anticoagulants before admission, it is recommended to replace them by low molecular weight heparin (LMWH) at therapeutic doses; 3. Thromboprophylaxis with LMWH at standard doses is suggested for COVID-19 patients admitted to a conventional hospital ward; 4. Standard-doses thromboprophylaxis with LMWH is recommended for COVID-19 patients requiring admission to Intensive Care Unit; 5. It is recommended not to determine D-Dimer levels routinely in COVID-19 hospitalized patients to select those in whom VTE should be suspected, or as a part of the diagnostic algorithm to rule out or confirm a VTE event; 6. It is recommended to discontinue pharmacological thromboprophylaxis at discharge in most patients hospitalized for COVID-19; 7. It is recommended to withdraw anticoagulant treatment after 3 months in most patients with a VTE event associated with COVID-19. The combination of PICO questions and DELPHI methodology provides a consensus on different recommendations for anticoagulation management in patients with COVID-19.

The clinical significance of ultra-high D-dimer levels

Objective

Plasma D-dimer levels >5000 ng/mL are encountered in a number of conditions other than venous thromboembolism (VTE). Recent studies have used plasma D-dimer levels as a prognostic indicator for coronavirus disease 2019 (COVID-19) infection. The implications of abnormal levels are less clear for patients diagnosed with COVID-19 with a baseline elevation in plasma D-dimer levels. In the present study, we reviewed the occurrence of plasma D-dimer levels >5000 ng/mL and investigated the clinical significance of this finding before the onset of the COVID-19 pandemic.

Methods

Inpatient records for a 4-year period were screened for laboratory results of plasma D-dimer levels >5000 ng/mL. The patient data were reviewed for the clinical identifiers commonly associated with elevated plasma D-dimer levels, including VTE, cancer, sepsis, pneumonia, other infection, bleeding, and trauma. The patients were then categorized into groups stratified by the plasma D-dimer level to allow for comparisons between the various clinical diagnoses.

Results

A total of 671 patients were included in the present study. VTE was the most common diagnosis for patients with a plasma D-dimer level >5000 ng/mL, followed by cancer and pneumonia. Multiple clinical diagnoses were present in 61% of the patients. No clear cause for the ultra-high plasma D-dimer level could be identified in 11.3% of the patients. Among the patients lacking a clinical diagnosis at discharge, mortality was 24% in the 5000- to 10,000-ng/mL group, 28.6% in the 10,000- to 15,000-ng/mL group, and 75% in the >15,000-ng/mL group.

Conclusions

VTE, cancer, and pneumonia were frequently present when ultra-high plasma D-dimer levels were encountered, and mortality was high when the levels were >15,000 ng/mL. The results from our study from a pre–COVID-19 patient population suggest that ultra-high plasma D-dimer levels indicate the presence of severe underlying disease. This should be considered when using the plasma D-dimer level as a screening tool or prognostic indicator for COVID-19 infection.

The Potency of Seaweed Sulfated Polysaccharides for the Correction of Hemostasis Disorders in COVID-19

Hemostasis disorders play an important role in the pathogenesis, clinical manifestations, and outcome of COVID-19. First of all, the hemostasis system suffers due to a complicated and severe course of COVID-19. A significant number of COVID-19 patients develop signs of hypercoagulability, thrombocytopenia, and hyperfibrinolysis. Patients with severe COVID-19 have a tendency toward thrombotic complications in the venous and arterial systems, which is the leading cause of death in this disease. Despite the success achieved in the treatment of SARS-CoV-2, the search for new effective anticoagulants, thrombolytics, and fibrinolytics, as well as their optimal dose strategies, continues to be relevant. The wide therapeutic potential of seaweed sulfated polysaccharides (PSs), including anticoagulant, thrombolytic, and fibrinolytic activities, opens up new possibilities for their study in experimental and clinical trials. These natural compounds can be important complementary drugs for the recovery from hemostasis disorders due to their natural origin, safety, and low cost compared to synthetic drugs. In this review, the authors analyze possible pathophysiological mechanisms involved in the hemostasis disorders observed in the pathological progression of COVID-19, and also focus the attention of researchers on seaweed PSs as potential drugs aimed to correction these disorders in COVID-19 patients. Modern literature data on the anticoagulant, antithrombotic, and fibrinolytic activities of seaweed PSs are presented, depending on their structural features (content and position of sulfate groups on the main chain of PSs, molecular weight, monosaccharide composition and type of glycosidic bonds, the degree of PS chain branching, etc.). The mechanisms of PS action on the hemostasis system and the issues of oral bioavailability of PSs, important for their clinical use as oral anticoagulant and antithrombotic agents, are considered. The combination of the anticoagulant, thrombolytic, and fibrinolytic properties, along with low toxicity and relative cheapness of production, open up prospects for the clinical use of PSs as alternative sources of new anticoagulant and antithrombotic compounds. However, further investigation and clinical trials are needed to confirm their efficacy.