Coronavirus Disease 2019-Associated Thrombosis and Coagulopathy: Review of the Pathophysiological Characteristics and Implications for Antithrombotic Management

Thromboinflammation in COVID-19: Unraveling the interplay of coagulation and inflammation

The coronavirus disease 2019 (COVID-19) pandemic has not only challenged global health systems but also spurred intense scientific inquiry into its pathophysiology. Among the multifaceted aspects of the disease, coagulation abnormalities have emerged as a significant contributor to morbidity and mortality. From endothelial dysfunction to dysregulated immune responses, various factors contribute to the hypercoagulable state seen in severe COVID-19 cases. The dysregulation of coagulation in COVID-19 extends beyond traditional thromboembolic events, encompassing a spectrum of abnormalities ranging from microvascular thrombosis to disseminated intravascular coagulation (DIC). Endothelial injury induced by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection triggers a cascade of events involving platelet activation, coagulation factor consumption, and fibrinolysis impairment. Moreover, the virus direct effects on immune cells and the cytokine storm further exacerbate the prothrombotic milieu. Unraveling this intricate web of interactions between viral pathogenesis and host responses is essential for elucidating novel therapeutic targets and refining existing management strategies for COVID-19-associated coagulopathy. In the quest to unravel the complex interplay between coagulation and COVID-19, numerous clinical and laboratory studies have yielded invaluable insights into potential biomarkers, prognostic indicators, and therapeutic avenues. Anticoagulation therapy has emerged as a cornerstone in the management of severe COVID-19, although optimal dosing regimens and patient selection criteria remain subjects of ongoing investigation. Additionally, innovative approaches such as targeting specific components of the coagulation cascade or modulating endothelial function hold promise for future therapeutic development.

Blood perfusion with polymyxin B immobilized columns in patients with COVID-19 requiring oxygen therapy

Extracorporeal blood purification with polymyxin B immobilized fiber column direct hemoperfusion (PMX-DHP), is reported to be effective in treating COVID-19 pneumonitis with oxygen demand. This multicenter prospective study evaluated the efficacy and safety of PMX-DHP in oxygen-requiring patients with COVID-19 admitted between September 28, 2020, and March 31, 2022. The primary endpoint was the percentage of clinical improvement 15 days after treatment. The secondary endpoint was the percentage of worsened disease status. Data from the COVID-19 patient registry were used for the synthetic control group. The improvement rate on Day 15 did not differ between PMX-treated patients and controls; however, the deterioration rate was 0.38 times lower in the PMX-treated group, and the death rates on Day 29 were 0 and 11.1% in the PMX-treated and control groups, respectively. The PMX group showed a 0.73 times higher likelihood for reduced intensive care demand, as 16.7% of PMX-treated patients and 22.8% of controls worsened. After treatment blood oxygenation improved, urinary β2-microglobulin and liver-type fatty acid-binding protein showed significant decreases, and IL-6 decreased once during treatment but did not persist. In this study, PMX treatment effectively prevented the worsening of COVID-19 pathology, accompanied by improved oxygenation. PMX treatment to remove activated cells may effectively improve patient outcomes.

Myocardial Oedema as a Consequence of Viral Infection and Persistence-A Narrative Review with Focus on COVID-19 and Post COVID Sequelae

Microvascular integrity is a critical factor in myocardial fluid homeostasis. The subtle equilibrium between capillary filtration and lymphatic fluid removal is disturbed during pathological processes leading to inflammation, but also in hypoxia or due to alterations in vascular perfusion and coagulability. The degradation of the glycocalyx as the main component of the endothelial filtration barrier as well as pericyte disintegration results in the accumulation of interstitial and intracellular water. Moreover, lymphatic dysfunction evokes an increase in metabolic waste products, cytokines and inflammatory cells in the interstitial space contributing to myocardial oedema formation. This leads to myocardial stiffness and impaired contractility, eventually resulting in cardiomyocyte apoptosis, myocardial remodelling and fibrosis. The following article reviews pathophysiological inflammatory processes leading to myocardial oedema including myocarditis, ischaemia-reperfusion injury and viral infections with a special focus on the pathomechanisms evoked by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. In addition, clinical implications including potential long-term effects due to viral persistence (long COVID), as well as treatment options, are discussed.

Simultaneous Double-Vessel Coronary Thrombosis with Sudden Cardiac Arrest as the First Manifestation of COVID-19

The relationship between coronavirus disease 2019 (COVID-19) and myocardial injury was established at the onset of the COVID-19 pandemic. An increase in the incidence of out-of-hospital cardiac arrest was also observed. This case report aims to point to the prothrombotic and proinflammatory nature of coronavirus infection, leading to simultaneous coronary vessel thrombosis and subsequently to out-of-hospital cardiac arrest. During the COVID-19 pandemic, a 46-year-old male patient with no comorbidities suffered out-of-hospital cardiac arrest (OHCA) with ventricular fibrillation as the first recorded rhythm. The applied cardiopulmonary resuscitation (CPR) measures initiated by bystanders and continued by emergency medical service (EMS) resulted in the return of spontaneous circulation. The stabilized patient was transferred to the tertiary university center. Electrocardiogram (ECG) revealed "lambda-like" ST-segment elevation in DI and aVL leads, necessitating an immediate coronary angiography, which demonstrated simultaneous occlusion of the left anterior descending (LAD) and right coronary artery (RCA). Primary percutaneous coronary intervention (PCI) with the implantation of one drug-eluting stent (DES) in LAD and two DES in RCA was done. Due to the presence of cardiogenic shock (SCAI C), an intra-aortic balloon pump (IABP) was implanted during the procedure, and due to the comatose state and shockable cardiac arrest, targeted temperature management was initiated. The baseline chest X-ray revealed bilateral interstitial infiltrates, followed by increased proinflammatory markers and a positive polymerase chain reaction (PCR) test for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) demasking underlying COVID-19-related pneumonia. Within the following 48 h, the patient was hemodynamically stable, which enabled weaning from IABP and vasopressor discontinuation. However, due to the worsening of COVID-19 pneumonia, prolonged mechanical ventilation, together with antibiotics and other supportive measures, was needed. The applied therapy resulted in clinical improvement, and the patient was extubated and finally discharged on Day 26, with no neurological sequelae and with mildly reduced left ventricle ejection fraction.

Persistent, Poorly Responsive Immune Thrombocytopenia Secondary to Asymptomatic COVID-19 Infection in a Child

Immune thrombocytopenic purpura (ITP) secondary to asymptomatic COVID-19 infection, especially in children, is not reported. Furthermore, persistent, treatment-resistant ITP secondary to COVID-19 is not reported. We report a previously healthy 14-year-old Asian boy who developed secondary ITP following an asymptomatic COVID-19 infection and is having a relapsing and remitting cause with poor response to immunosuppressants even after 21 months following the diagnosis. This case emphasizes the importance of testing for COVID-19 in newly diagnosed ITP patients and the need for follow-up platelet counts in patients who recover from COVID-19 as it may follow into developing secondary ITP yet being asymptomatic until you present with a bleeding complication of ITP. The poor response to standard immunosuppression warrants more understanding of the pathophysiology of persistently low platelets following COVID-19 infection. Long-term sequelae of the disease highlight the importance of getting vaccinated for COVID-19 despite COVID-19 being no longer a global emergency.

COVID-19-Associated Pulmonary Embolism: Review of the Pathophysiology, Epidemiology, Prevention, Diagnosis, and Treatment

COVID-19 is associated with endothelial activation in the setting of a potent inflammatory reaction and a hypercoagulable state. The end result of this thromboinflammatory state is an excess in thrombotic events, in particular venous thromboembolism. Pulmonary embolism (PE) has been of special interest in patients with COVID-19 given its association with respiratory deterioration, increased risk of intensive care unit admission, and prolonged hospital stay. The pathophysiology and clinical characteristics of COVID-19-associated PE may differ from the conventional non-COVID-19-associated PE. In addition to embolic events from deep vein thrombi, in situ pulmonary thrombosis, particularly in smaller vascular beds, may be relevant in patients with COVID-19. Appropriate prevention of thrombotic events in COVID-19 has therefore become of critical interest. Several changes in viral biology, vaccination, and treatment management during the pandemic may have resulted in changes in incidence trends. This review provides an overview of the pathophysiology, epidemiology, clinical characteristics, and risk factors of COVID-19-associated PE. Furthermore, we briefly summarize the results from randomized controlled trials of preventive antithrombotic therapies in COVID-19, focusing on their findings related to PE. We discuss the acute treatment of COVID-19-associated PE, which is substantially similar to the management of conventional non-COVID-19 PE. Ultimately, we comment on the current knowledge gaps in the evidence and the future directions in the treatment and follow-up of COVID-19-associated PE, including long-term management, and its possible association with long-COVID.

Cerebral venous sinus thrombosis related to SARS-CoV-2 infection in a pediatric patient: A case report

Coronavirus disease 2019 is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2); it has recently been associated with several hematologic disorders. A 4-year-old boy who had SARS-CoV-2 10 months prior was admitted to the emergency department of our hospital with seizures. His SARS-CoV-2 IgG II level was 885.7 AU/mL. Neuroimaging with cranial computed tomography after admission showed abnormal images of the venous sinus, but this was not sufficient to diagnose cerebral venous sinus thrombosis. Therefore, magnetic resonance imaging and digital subtraction angiography were conducted, which confirmed the diagnosis. He was treated with thrombectomy and anticoagulation drugs, and the clinical outcomes were satisfactory. Because our patient had a medical history of SARS-CoV-2 and exhibited no other risk factors, we present this case as evidence of a potential association between cerebral venous sinus thrombosis and SARS-CoV-2.

Association of Serum Complement C3 Levels with Severity and Mortality in COVID 19

The severe acute respiratory distress syndrome-associated coronavirus-2 infection can activate innate and adaptive immune responses which may lead to harmful tissue damage, both locally and systemically. C3, a member of complement system of serum proteins, is a major component of innate immune and inflammatory responses. This study is aimed to assess serum C3 as a marker of COVID-19 severity and a predictor of disease progression. A total of 150 COVID-19 patients, confirmed by RT-PCR, and 50 healthy controls were recruited. Serum C3 levels were determined by using direct colorimetric method. Median levels of serum C3 in total cases and controls were 157.8 and 165.7 mg/dL respectively. Serum C3 although not significantly decreased, they were lower in cases when compared to controls. Similarly, significant differences were found between the groups, with severe group (140.6 mg/dL) having low levels of serum C3 protein when compared to mild (161.0 mg/dL) and moderate group (167.1 mg/dL). Interestingly, during hospitalization, significant difference between baseline (admission) and follow-up (discharge) was observed only in patients with moderate disease. Based on our results, lower levels of C3, with an increase in IL-6 and d-dimer levels, are associated with higher odds of mortality. Therefore, we would like to emphasize that measuring serum C3 levels along with other inflammatory markers might give an added advantage in early identification of patients who are prone to having a severe disease course and can help in a more effective follow-up of disease progression.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12291-023-01148-x.

Prophylactic anticoagulants for non-hospitalised people with COVID-19

BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic has impacted healthcare systems worldwide. Multiple reports on thromboembolic complications related to COVID-19 have been published, and researchers have described that people with COVID-19 are at high risk for developing venous thromboembolism (VTE). Anticoagulants have been used as pharmacological interventions to prevent arterial and venous thrombosis, and their use in the outpatient setting could potentially reduce the prevalence of vascular thrombosis and associated mortality in people with COVID-19. However, even lower doses used for a prophylactic purpose may result in adverse events such as bleeding. It is important to consider the evidence for anticoagulant use in non-hospitalised people with COVID-19.

OBJECTIVES

To evaluate the benefits and harms of prophylactic anticoagulants versus active comparators, placebo or no intervention, or non-pharmacological interventions in non-hospitalised people with COVID-19.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search date was 18 April 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing prophylactic anticoagulants with placebo or no treatment, another active comparator, or non-pharmacological interventions in non-hospitalised people with COVID-19. We included studies that compared anticoagulants with a different dose of the same anticoagulant. We excluded studies with a duration of under two weeks.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodological procedures. Our primary outcomes were all-cause mortality, VTE (deep vein thrombosis (DVT) or pulmonary embolism (PE)), and major bleeding. Our secondary outcomes were DVT, PE, need for hospitalisation, minor bleeding, adverse events, and quality of life. We used GRADE to assess the certainty of the evidence.

MAIN RESULTS

We included five RCTs with up to 90 days of follow-up (short term). Data were available for meta-analysis from 1777 participants. Anticoagulant compared to placebo or no treatment Five studies compared anticoagulants with placebo or no treatment and provided data for three of our outcomes of interest (all-cause mortality, major bleeding, and adverse events). The evidence suggests that prophylactic anticoagulants may lead to little or no difference in all-cause mortality (risk ratio (RR) 0.36, 95% confidence interval (CI) 0.04 to 3.61; 5 studies; 1777 participants; low-certainty evidence) and probably reduce VTE from 3% in the placebo group to 1% in the anticoagulant group (RR 0.36, 95% CI 0.16 to 0.85; 4 studies; 1259 participants; number needed to treat for an additional beneficial outcome (NNTB) = 50; moderate-certainty evidence). There may be little to no difference in major bleeding (RR 0.36, 95% CI 0.01 to 8.78; 5 studies; 1777 participants; low-certainty evidence). Anticoagulants probably result in little or no difference in DVT (RR 1.02, 95% CI 0.30 to 3.46; 3 studies; 1009 participants; moderate-certainty evidence), but probably reduce the risk of PE from 2.7% in the placebo group to 0.7% in the anticoagulant group (RR 0.25, 95% CI 0.08 to 0.79; 3 studies; 1009 participants; NNTB 50; moderate-certainty evidence). Anticoagulants probably lead to little or no difference in reducing hospitalisation (RR 1.01, 95% CI 0.59 to 1.75; 4 studies; 1459 participants; moderate-certainty evidence) and may lead to little or no difference in adverse events (minor bleeding, RR 2.46, 95% CI 0.90 to 6.72; 5 studies, 1777 participants; low-certainty evidence). Anticoagulant compared to a different dose of the same anticoagulant One study compared anticoagulant (higher-dose apixaban) with a different (standard) dose of the same anticoagulant and reported five relevant outcomes. No cases of all-cause mortality, VTE, or major bleeding occurred in either group during the 45-day follow-up (moderate-certainty evidence). Higher-dose apixaban compared to standard-dose apixaban may lead to little or no difference in reducing the need for hospitalisation (RR 1.89, 95% CI 0.17 to 20.58; 1 study; 278 participants; low-certainty evidence) or in the number of adverse events (minor bleeding, RR 0.47, 95% CI 0.09 to 2.54; 1 study; 278 participants; low-certainty evidence). Anticoagulant compared to antiplatelet agent One study compared anticoagulant (apixaban) with antiplatelet agent (aspirin) and reported five relevant outcomes. No cases of all-cause mortality or major bleeding occurred during the 45-day follow-up (moderate-certainty evidence). Apixaban may lead to little or no difference in VTE (RR 0.36, 95% CI 0.01 to 8.65; 1 study; 279 participants; low-certainty evidence), need for hospitalisation (RR 3.20, 95% CI 0.13 to 77.85; 1 study; 279 participants; low-certainty evidence), or adverse events (minor bleeding, RR 2.13, 95% CI 0.40 to 11.46; 1 study; 279 participants; low-certainty evidence). No included studies reported on quality of life or investigated anticoagulants compared to a different anticoagulant, or anticoagulants compared to non-pharmacological interventions.

AUTHORS' CONCLUSIONS

We found low- to moderate-certainty evidence from five RCTs that prophylactic anticoagulants result in little or no difference in major bleeding, DVT, need for hospitalisation, or adverse events when compared with placebo or no treatment in non-hospitalised people with COVID-19. Low-certainty evidence indicates that prophylactic anticoagulants may result in little or no difference in all-cause mortality when compared with placebo or no treatment, but moderate-certainty evidence indicates that prophylactic anticoagulants probably reduce the incidence of VTE and PE. Low-certainty evidence suggests that comparing different doses of the same prophylactic anticoagulant may result in little or no difference in need for hospitalisation or adverse events. Prophylactic anticoagulants may result in little or no difference in risk of VTE, hospitalisation, or adverse events when compared with antiplatelet agents (low-certainty evidence). Given that there were only short-term data from one study, these results should be interpreted with caution. Additional trials of sufficient duration are needed to clearly determine any effect on clinical outcomes.

Direct endothelial ENaC activation mitigates vasculopathy induced by SARS-CoV2 spike protein

Introduction

Although both COVID-19 and non-COVID-19 ARDS can be accompanied by significantly increased levels of circulating cytokines, the former significantly differs from the latter by its higher vasculopathy, characterized by increased oxidative stress and coagulopathy in lung capillaries. This points towards the existence of SARS-CoV2-specific factors and mechanisms that can sensitize the endothelium towards becoming dysfunctional. Although the virus is rarely detected within endothelial cells or in the circulation, the S1 subunit of its spike protein, which contains the receptor binding domain (RBD) for human ACE2 (hACE2), can be detected in plasma from COVID-19 patients and its levels correlate with disease severity. It remains obscure how the SARS-CoV2 RBD exerts its deleterious actions in lung endothelium and whether there are mechanisms to mitigate this.

Methods

In this study, we use a combination of in vitro studies in RBD-treated human lung microvascular endothelial cells (HL-MVEC), including electrophysiology, barrier function, oxidative stress and human ACE2 (hACE2) surface protein expression measurements with in vivo studies in transgenic mice globally expressing human ACE2 and injected with RBD.

Results

We show that SARS-CoV2 RBD impairs endothelial ENaC activity, reduces surface hACE2 expression and increases reactive oxygen species (ROS) and tissue factor (TF) generation in monolayers of HL-MVEC, as such promoting barrier dysfunction and coagulopathy. The TNF-derived TIP peptide (a.k.a. solnatide, AP301) -which directly activates ENaC upon binding to its a subunit- can override RBD-induced impairment of ENaC function and hACE2 expression, mitigates ROS and TF generation and restores barrier function in HL-MVEC monolayers. In correlation with the increased mortality observed in COVID-19 patients co-infected with S. pneumoniae, compared to subjects solely infected with SARS-CoV2, we observe that prior intraperitoneal RBD treatment in transgenic mice globally expressing hACE2 significantly increases fibrin deposition and capillary leak upon intratracheal instillation of S. pneumoniae and that this is mitigated by TIP peptide treatment.

Correlation between Hepatocyte Growth Factor (HGF) with D-Dimer and Interleukin-6 as Prognostic Markers of Coagulation and Inflammation in Long COVID-19 Survivors

In general, an individual who experiences the symptoms of Severe Acute Respiratory Syndrome Coronavirus 2 or SARS-CoV-2 infection is declared as recovered after 2 weeks. However, approximately 10-20% of these survivors have been reported to encounter long-term health problems, defined as 'long COVID-19', e.g., blood coagulation which leads to stroke with an estimated incidence of 3%, and pulmonary embolism with 5% incidence. At the time of infection, the immune response produces pro-inflammatory cytokines that stimulate stromal cells to produce pro-hepatocyte growth factor (pro-HGF) and eventually is activated into hepatocyte growth factor (HGF), which helps the coagulation process in endothelial and epithelial cells. HGF is a marker that appears as an inflammatory response that leads to coagulation. Currently, there is no information on the effect of SARS-CoV-2 infection on serum HGF concentrations as a marker of the prognosis of coagulation in long COVID-19 survivors. This review discusses the pathophysiology between COVID-19 and HGF, IL-6, and D-dimer.

Distinct Features of Vascular Diseases in COVID-19

The Coronavirus Disease 2019 (COVID-19) pandemic was declared in early 2020 after several unexplained pneumonia cases were first reported in Wuhan, China, and subsequently in other parts of the world. Commonly, the disease comprises several clinical features, including high temperature, dry cough, shortness of breath, and hypoxia, associated with findings of interstitial pneumonia on chest X-ray and computer tomography. Nevertheless, severe forms of acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) are not limited to the respiratory tract but also may be extended to other systems, including the cardiovascular system. The bi-directional relationship between atherosclerosis and COVID-19 is accompanied by poor prognosis. The immune response hyperactivation due to SARS-CoV-2 infection causes an increased secretion of cytokines, endothelial dysfunction, and arterial stiffness, which promotes the development of atherosclerosis. Also, due to the COVID-19 pandemic, access to healthcare amenities was reduced, resulting in increased morbidity and mortality in patients at risk. Furthermore, as lockdown measures were largely adopted worldwide, the sedentary lifestyle and the increased consumption of processed nutrients or unhealthy food increased, and in the consequence, we might observe even 70% of overweight and obese population. Altogether, with the relatively low ratio of vaccinated people in many countries, and important health debt appeared, which is now and will be for next decade a large healthcare challenge. However, the experience gained in the COVID-19 pandemic and the new methods of patients' approaching have helped the medical system to overcome this crisis and will hopefully help in the case of new possible epidemics.

Long COVID Syndrome: Lesson Learned and Future Implications

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus responsible for coronavirus disease 2019 (COVID-19), has caused severe illness and mortality on a global scale, with an impact not witnessed since the 1918-19 Spanish influenza pandemic [...].

The Role of NETosis and Complement Activation in COVID-19-Associated Coagulopathies

Inflammation-induced coagulopathy is a common complication associated with coronavirus disease 2019 (COVID-19). We aim to evaluate the association of NETosis and complement markers with each other as well as their association with thrombogenicity and disease severity in COVID-19. The study included hospitalized patients with an acute respiratory infection: patients with SARS-CoV2 infection (COVpos, n = 47) or either pneumonia or infection-triggered acute exacerbated COPD (COVneg, n = 36). Our results show that NETosis, coagulation, and platelets, as well as complement markers, were significantly increased in COVpos patients, especially in severely ill COVpos patients. NETosis marker MPO/DNA complexes correlated with coagulation, platelet, and complement markers only in COVpos. Severely ill COVpos patients showed an association between complement C3 and SOFA (R = 0.48; p ≤ 0.028), C5 and SOFA (R = 0.46; p ≤ 0.038), and C5b-9 and SOFA (R = 0.44; p ≤ 0.046). This study provides further evidence that NETosis and the complement system are key players in COVID-19 inflammation and clinical severity. Unlike previous studies that found NETosis and complement markers to be elevated in COVID-19 patients compared to healthy controls, our findings show that this characteristic distinguishes COVID-19 from other pulmonary infectious diseases. Based on our results, we propose that COVID-19 patients at high risk for immunothrombosis could be identified via elevated complement markers such as C5.

Galectin-3 as a Marker for Increased Thrombogenicity in COVID-19

Galectin-3 is a beta-galactoside-binding lectin involved in inflammation and lung fibrosis and postulated to enhance thrombosis. In COVID-19, it is considered to be a prognostic marker of severity. The aim of this study was to evaluate whether galectin-3 is associated with thrombogenicity in COVID-19. Patients with moderate-to-severe COVID-19 (COVpos; n = 55) and patients with acute respiratory diseases, but without COVID-19 (COVneg; n = 35), were included in the study. We measured the amount of galectin-3, as well as other platelet and coagulation markers, and correlated galectin-3 levels with these markers of thrombogenicity and with the SOFA Score values. We found that galectin-3 levels, as well as von Willebrand Factor (vWF), antithrombin and tissue plasminogen activator levels, were higher in the COVpos than they were in the COVneg cohort. Galectin-3 correlated positively with vWF, antithrombin and D-dimer in the COVpos cohort, but not in the COVneg cohort. Moreover, galactin-3 correlated also with clinical disease severity, as measured by the SOFA Score. In patients with acute respiratory diseases, galectin-3 can be considered as a marker not only for disease severity, but also for increased hypercoagulability. Whether galectin-3 might be a useful therapeutic target in COVID-19 needs to be assessed in future studies.

Risk of Thrombosis during and after a SARS-CoV-2 Infection: Pathogenesis, Diagnostic Approach, and Management

Coronavirus disease 2019 (COVID-19) increases the risk of thromboembolic events, especially in patients with severe infections requiring intensive care and cardiorespiratory support. COVID-19 patients with thromboembolic complications have a higher risk of death, and if they survive, these complications are expected to negatively affect these patients’ quality of life. Moreover, recent data reported that the risk of thromboembolism remains high months after a COVID-19 infection. Therefore, understanding the pathogenesis of thrombosis in the setting of COVID-19 may facilitate the early prevention and treatment of COVID-19-associated thromboembolism to reduce concomitant morbidity, mortality, and disability. This review will first discuss the clinical characteristics of COVID-19 infections, particularly with regard to the underlying pathophysiology. Then, the pathogenesis of COVID-19-associated thrombosis at the molecular and cellular levels will be comprehensively reviewed. Next, the clinical manifestations of venous and arterial thromboembolism in COVID-19 as well as the potential benefits of several laboratory markers of thrombosis will be further discussed. Lastly, the preventive and therapeutic management of thromboembolism during and after COVID-19 will also be explained.

COVID-19-Associated Coagulopathy: Ascending Aortic Thrombus

The mechanism of arterial thrombosis in coronavirus disease 2019 (COVID-19) is not completely understood and is attributed to the complex interactions of endothelial injury, platelet hyperactivation, and activated pro-inflammatory cytokines. Management strategies may include a combination of surgery and anticoagulation, or anticoagulation alone. A 56-year-old woman with recent COVID-19 infection presented with chest pain and dyspnea. Chest CT angiography (CTA) and aortic magnetic resonance imaging revealed an intraluminal thrombus in the mid ascending aorta. A multidisciplinary team decided on heparin infusion. She was transitioned to apixaban and a three-month interval outpatient CTA revealed complete resolution of the aortic thrombus.

Platelet activation and coronavirus disease 2019 mortality: Insights from coagulopathy, antiplatelet therapy and inflammation

BACKGROUND

Coronavirus disease 2019 (COVID-19) is associated with an inflammatory cytokine burst and a prothrombotic coagulopathy. Platelets may contribute to microthrombosis, and constitute a therapeutic target in COVID-19 therapy.

AIM

To assess if platelet activation influences mortality in COVID-19.

METHODS

We explored two cohorts of patients with COVID-19. Cohort A included 208 ambulatory and hospitalized patients with varying clinical severities and non-COVID patients as controls, in whom plasma concentrations of the soluble platelet activation biomarkers CD40 ligand (sCD40L) and P-selectin (sP-sel) were quantified within the first 48hours following hospitalization. Cohort B was a multicentre cohort of 2878 patients initially admitted to a medical ward. In both cohorts, the primary outcome was in-hospital mortality.

RESULTS

In cohort A, median circulating concentrations of sCD40L and sP-sel were only increased in the 89 critical patients compared with non-COVID controls: sP-sel 40,059 (interquartile range 26,876-54,678)pg/mL; sCD40L 1914 (interquartile range 1410-2367)pg/mL (P<0.001 for both). A strong association existed between sP-sel concentration and in-hospital mortality (Kaplan-Meier log-rank P=0.004). However, in a Cox model considering biomarkers of immunothrombosis, sP-sel was no longer associated with mortality, in contrast to coagulopathy evaluated with D-dimer concentration (hazard ratio 4.86, 95% confidence interval 1.64-12.50). Moreover, in cohort B, a Cox model adjusted for co-morbidities suggested that prehospitalization antiplatelet agents had no significant impact on in-hospital mortality (hazard ratio 1.05, 95% CI 0.80-1.37; P=0.73).

CONCLUSIONS

Although we observed an association between excessive biomarkers of platelet activation and in-hospital mortality, our findings rather suggest that coagulopathy is more central in driving disease progression, which may explain why prehospitalization antiplatelet drugs were not a protective factor against mortality in our multicentre cohort.

Saponins: Research Progress and Their Potential Role in the Post-COVID-19 Pandemic Era

In the post-COVID-19 pandemic era, the new global situation and the limited therapeutic management of the disease make it necessary to take urgent measures in more effective therapies and drug development in order to counteract the negative global impacts caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its new infectious variants. In this context, plant-derived saponins-glycoside-type compounds constituted from a triterpene or steroidal aglycone and one or more sugar residues-may offer fewer side effects and promising beneficial pharmacological activities. This can then be used for the development of potential therapeutic agents against COVID-19, either as a therapy or as a complement to conventional pharmacological strategies for the treatment of the disease and its prevention. The main objective of this review was to examine the primary and current evidence in regard to the therapeutic potential of plant-derived saponins against the COVID-19 disease. Further, the aim was to also focus on those studies that highlight the potential use of saponins as a treatment against SARS-CoV-2. Saponins are antiviral agents that inhibit different pharmacological targets of the virus, as well as exhibit anti-inflammatory and antithrombotic activity in relieving symptoms and clinical complications related to the disease. In addition, saponins also possess immunostimulatory effects, which improve the efficacy and safety of vaccines for prolonging immunogenicity against SARS-CoV-2 and its infectious variants.

Extracellular Vesicles: New Players in the Mechanisms of Sepsis- and COVID-19-Related Thromboinflammation

Sepsis and COVID-19 patients often manifest an imbalance in inflammation and coagulation, a complex pathological mechanism also named thromboinflammation, which strongly affects patient prognosis. Extracellular vesicles (EVs) are nanoparticles released by cells into extracellular space that have a relevant role in cell-to-cell communication. Recently, EVs have been shown to act as important players in a variety of pathologies, including cancer and cardiovascular disease. The biological properties of EVs in the mechanisms of thromboinflammation during sepsis and COVID-19 are still only partially known. Herein, we summarize the current experimental evidence on the role of EVs in thromboinflammation, both in bacterial sepsis and in COVID-19. A better understanding of EV involvement in these processes could be useful in describing novel diagnostic and therapeutic applications of EVs in these diseases.

Unilateral Limb Ischemia in a COVID-19 Patient: A Case Report

Coronavirus disease 2019 (COVID-19) has been primarily linked to respiratory complications, including acute respiratory distress syndrome (ARDS). However, several systemic manifestations of the disease may also occur. One of the emerging complications that is being increasingly reported in the literature is the hypercoagulable and intense inflammatory state in COVID-19 patients, which leads to venous and/or arterial thrombosis, vasospasm, and ischemia. Despite the recent advances in diagnostic and treatment modalities, the diagnosis and management of vascular ischemia in this patient population remain a challenge, resulting in increased morbidity and mortality. In this case report, we highlight the etiology and potential treatment of limb ischemia in COVID-19 patients.

One-year cardiovascular outcomes after coronavirus disease 2019: The cardiovascular COVID-19 registry

BACKGROUND

The long-term cardiovascular (CV) outcomes of COVID-19 have not been fully explored.

METHODS

This was an international, multicenter, retrospective cohort study conducted between February and December 2020. Consecutive patients ≥18 years who underwent a real-time reverse transcriptase-polymerase chain reaction (RT-PCR) for SARS-CoV2 were included. Patients were classified into two cohorts depending on the nasopharyngeal swab result and clinical status: confirmed COVID-19 (positive RT-PCR) and control (without suggestive symptoms and negative RT-PCR). Data were obtained from electronic records, and clinical follow-up was performed at 1-year. The primary outcome was CV death at 1-year. Secondary outcomes included arterial thrombotic events (ATE), venous thromboembolism (VTE), and serious cardiac arrhythmias. An independent clinical event committee adjudicated events. A Cox proportional hazards model adjusted for all baseline characteristics was used for comparing outcomes between groups. A prespecified landmark analysis was performed to assess events during the post-acute phase (31-365 days).

RESULTS

A total of 4,427 patients were included: 3,578 (80.8%) in the COVID-19 and 849 (19.2%) control cohorts. At one year, there were no significant differences in the primary endpoint of CV death between the COVID-19 and control cohorts (1.4% vs. 0.8%; HRadj 1.28 [0.56-2.91]; p = 0.555), but there was a higher risk of all-cause death (17.8% vs. 4.0%; HRadj 2.82 [1.99-4.0]; p = 0.001). COVID-19 cohort had higher rates of ATE (2.5% vs. 0.8%, HRadj 2.26 [1.02-4.99]; p = 0.044), VTE (3.7% vs. 0.4%, HRadj 9.33 [2.93-29.70]; p = 0.001), and serious cardiac arrhythmias (2.5% vs. 0.6%, HRadj 3.37 [1.35-8.46]; p = 0.010). During the post-acute phase, there were no significant differences in CV death (0.6% vs. 0.7%; HRadj 0.67 [0.25-1.80]; p = 0.425), but there was a higher risk of deep vein thrombosis (0.6% vs. 0.0%; p = 0.028). Re-hospitalization rate was lower in the COVID-19 cohort compared to the control cohort (13.9% vs. 20.6%; p = 0.001).

CONCLUSIONS

At 1-year, patients with COVID-19 experienced an increased risk of all-cause death and adverse CV events, including ATE, VTE, and serious cardiac arrhythmias, but not CV death.

STUDY REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifier: NCT04359927.

Impact of COVID-19 Diagnosis on Mortality in Patients with ST-Elevation Myocardial Infarction Hospitalized during the National Outbreak in Italy

Background. We sought to assess the clinical impact of COVID-19 infection on mortality in patients with ST-elevation myocardial infarction (STEMI) admitted during the national outbreak in Italy. Methods. We analysed a nationwide, comprehensive, and universal administrative database of consecutive STEMI patients admitted during lockdown for COVID-19 infection (11 March−3 May 2020) and the equivalent periods of the previous 5 years in Italy. The observed rate of 30-day and 6-month all-cause mortality of STEMI patients with and without COVID-19 infection during the lockdown was compared with the expected rate of death, according to the trend of the previous 5 years. Results. During the study period, 32.910 STEMI hospitalizations occurred in Italy. Among these, 4048 STEMI patients were admitted during the 2020 outbreak: 170 (4.2%) with and 3878 (95.8%) without a COVID-19 diagnosis. According to the 5-year trend, the 2020 expected rates of 30-day and 6-month all-cause mortality were 9.2% and 12.6%, while the observed incidences of death were 10.8% (p = 0.016) and 14.4% (p = 0.017), respectively. Excluding STEMI patients with a COVID-19 diagnosis, the mortality rate resulted in accordance with the prior 5-year trend. After multiple corrections, the presence of COVID-19 diagnosis was an independent predictor of all-cause mortality at 30 days [adjusted odds ratio (OR) 4.5; 95% confidence intervals (CI) 3.09−6.45; p < 0.0001] and 6 months (adjusted OR 3.6; 95% CI: 2.47−5.12; p < 0.0001). Conclusions.During the 2020 national outbreak in Italy, COVID-19 infection significantly increased the mortality trend in patients with STEMI.

Newly diagnosed autoimmune Addison's disease in a patient with COVID-19 with autoimmune disseminated encephalomyelitis

A man in his 20s with a history of acute disseminated encephalomyelitis (ADEM) was brought into the emergency department (ED) after his family found him at home collapsed on the floor unresponsive with a blood glucose of 28 mg/dL at the field. In the ED, the patient was tachycardic, tachypnoeic and hypotensive, requiring pressors and intubation at 9 hours and 12 hours after arrival, respectively. Laboratory results revealed a positive COVID-19 test, serum sodium of 125 mmol/L and persistent hypoglycaemia. The patient was given a high dose of dexamethasone for COVID-19 treatment 1 hour before pressors were started. He was then continued on a stress dose of intravenous hydrocortisone with rapid clinical improvement leading to his extubation, and discontinuation of vasopressors and glucose on day 2 of admission. The patient received his last dose of intravenous hydrocortisone on day 4 in the early afternoon with the plan to order adrenal testing the following morning prior to discharge. On day 5, the aldosterone <3.0 ng/dL, adrenocorticotropic hormone (ACTH) level >1250 pg/mL, and ACTH stimulation test showed cortisol levels of 3 and 3 µg/dL at 30 and 60 min, respectively. The anti-21-hydroxylase antibody was positive. The patient was discharged on hydrocortisone and fludrocortisone. The patient's symptoms, elevated ACTH, low cortisol and presence of 21-hydroxylase antibodies are consistent with autoimmune Addison's disease. This is the first case reporting autoimmune Addison's disease in a patient with COVID-19 with a history of ADEM. The case highlights the importance of considering adrenal insufficiency as a diagnostic differential in haemodynamically unstable patients with COVID-19.

Elawad M, Abdalla ELM. Isolated Great Saphenous Vein Thrombosis in a Patient With COVID-19 Infection: Case Report and Review of the Literature

On 30 January 2020, the Director-General declared that the outbreak of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) constitutes a Public Health Emergency of International Concern (PHEIC), and on 11 March 2020, it was characterized as a pandemic. Since then, patients with COVID-19 infection are commonly reported to have an increased risk of thrombosis in various blood vessels due to hypercoagulability, blood stasis, and endothelial damage. In this study, we will present a case of a pregnant lady who was evaluated for right leg pain that started one week after having upper respiratory tract symptoms and COVID-19 infection confirmed by the COVID antigen (Ag) test. Further investigation with Doppler ultrasound (US) revealed complete right great saphenous vein thrombosis. This suggests that COVID-19 may lead to other adverse effects through damage to blood vessels.

Coagulation Profile of COVID-19 Patients

Coronavirus disease is a viral infection that can affect multiple systems and be expressed with many-or no-symptoms. The viral infection begins when the virus binds to the host's receptor and from that point on, it is transmitted to the rest of the body, where it causes inflammatory reactions. Among other tissues and systems, SARS-CoV-2 impacts the coagulation system, where it triggers the immunothrombotic response. Its effects are rather intense and can lead to many complications. COVID-19-associated coagulopathy is frequently observed in hospitalized patients, especially ICU patients, and can be proven detrimental. It is usually accompanied by other complications, such as sepsis-induced coagulopathy, disseminated intravascular coagulation and venous thromboembolism. Since all these conditions lead to poor prognosis for severely ill patients, thromboprophylaxis and coagulopathy prognosis are just as important as the therapeutic handling of these patients. Since the beginning of the pandemic, many biomarkers have been considered useful when trying to assess the thrombotic risk of hospitalized patients or evaluate the severity of their situation. At the same time, many drugs have already been tested-while others are still being trialed-in order to find the optimal therapy for each urgent situation.

Practical Recommendations for Optimal Thromboprophylaxis in Patients with COVID-19: A Consensus Statement Based on Available Clinical Trials

Coronavirus disease 2019 (COVID-19) has been shown to be strongly associated with increased risk for venous thromboembolism events (VTE) mainly in the inpatient but also in the outpatient setting. Pharmacologic thromboprophylaxis has been shown to offer significant benefits in terms of reducing not only VTE events but also mortality, especially in acutely ill patients with COVID-19. Although the main source of evidence is derived from observational studies with several limitations, thromboprophylaxis is currently recommended for all hospitalized patients with acceptable bleeding risk by all national and international guidelines. Recently, high quality data from randomized controlled trials (RCTs) further support the role of thromboprophylaxis and provide insights into the optimal thromboprophylaxis strategy. The aim of this statement is to systematically review all the available evidence derived from RCTs regarding thromboprophylaxis strategies in patients with COVID-19 in different settings (either inpatient or outpatient) and provide evidence-based guidance to practical questions in everyday clinical practice. Clinical questions accompanied by practical recommendations are provided based on data derived from 20 RCTs that were identified and included in the present study. Overall, the main conclusions are: (i) thromboprophylaxis should be administered in all hospitalized patients with COVID-19, (ii) an optimal dose of inpatient thromboprophylaxis is dependent upon the severity of COVID-19, (iii) thromboprophylaxis should be administered on an individualized basis in post-discharge patients with COVID-19 with high thrombotic risk, and (iv) thromboprophylaxis should not be routinely administered in outpatients. Changes regarding the dominant SARS-CoV-2 variants, the wide immunization status (increasing rates of vaccination and reinfections), and the availability of antiviral therapies and monoclonal antibodies might affect the characteristics of patients with COVID-19; thus, future studies will inform us about the thrombotic risk and the optimal therapeutic strategies for these patients.

Croatian study on COVID-19-positive stroke patients during the second wave of the pandemic

AIM

To investigate stroke characteristics in patients with concomitant coronavirus disease 2019 (COVID-19) infection in Croatia during the second wave of the COVID-19 pandemic.

METHODS

This retrospective study investigated the characteristics of two groups of ischemic stroke patients: those who developed COVID-19 infection before stroke and those who developed the infection during the hospital stay after stroke onset. Stroke etiology was classified according to the Trial of Org 10172 in Acute Stroke Treatment (TOAST) classification.

RESULTS

We analyzed data from 255 stroke patients from 12 Croatian hospitals. The two groups of ischemic stroke patients differed in stroke etiology (P=0.038). Patients with COVID-19 infection before stroke had fewer cardioembolic strokes (46% vs 29.1%), more cryptogenic strokes (32.5% vs 14.3%), and more strokes in multiple vascular territories (12.4% vs 1.8%). The percentage of large-vessel occlusions was high in both groups (49.6% and 44.4%). Median modified Rankin Scale score on discharge was 4 in both groups. Mortality was 36.4% in the group with stroke after COVID-19 and 33.3% in the group with COVID-19 after stroke.

CONCLUSION

Ischemic stroke after COVID-19 differs in etiology from ischemic stroke complicated by COVID-19 infection. Both patient groups are characterized by severe disability and high mortality. Raising the awareness of prehospital stroke and optimization of clinical workflow are important if we want to improve the stroke outcomes by acute recanalization techniques.

Thrombosis of Medium-Sized and Large Arteries During Covid-19 Infection: Results of the COVIVASC Study

BACKGROUND

COVID-19 infection is associated not only with venous thromboses but also with arterial thromboses (COV-ATs) in relation with an endothelial dysfunction, a coagulopathy and rhythm disorders. The incidence, the topography, and the prognosis of COV-ATs remain poorly known. The objective of this study was to report the overall experience of the Greater Paris University Hospitals (Assistance Publique - Hopitaux de Paris, AP-HP) during the first pandemic wave of COVID-19 infection.

METHODS

After approval by the ethics committee, a study using the AP-HP clinical data warehouse was carried out between March and May 2020. Overall, 124,609 patients had a polymerase chain reaction for COVID-19 in our hospitals, of which 25,345 were positive. From 20,710 exploitable stays, patients tested positive for COVID who presented an episode of acute COV-AT (except coronary and intracranial arteries) were selected on the basis of the French medical classification for clinical procedures codes. The data are presented as absolute values with percentages and/or means with standard deviation.

RESULTS

Over the studied period, 60 patients (aged 71±14 years, 42 men) presented a COV-AT at the time of their hospitalization, an incidence of 0.2%. The arterial complication occurred 3±7 days after the COVID infection and was inaugural in 30% of the cases (n = 18). The sites of COV-AT were the lower extremities (n = 35%, 58%), the abdominal aorta (n = 10%, 17%), the thoracic aorta (n = 7%, 12%), the upper limbs (n = 7%, 12%), the cerebral arteries (n = 7%, 12%), the digestive arteries (n = 6%, 10%), the renal arteries (n = 2%, 3%), and the ophthalmic artery (n = 1%, 2%). Multiple COV-ATs were observed in 13 patients (22%). At the time of diagnosis, 20 (33%) patients were in intensive care, including six (10%) patients who were intubated. On computed tomography angiography, COVID lesions were classified as moderate and severe in 25 (42%) and 21 (35%) cases, respectively. Revascularization was attempted in 27 patients (45%), by open surgery in 16 cases, using endovascular techniques in 8 cases and with a hybrid approach in three cases. Six patients (22%) required reinterventions. The duration of hospitalization was 12±9 days. Early mortality (in-hospital or at 30 days) was 30% (n = 18). Nine (15%) patients presented severe nonlethal ischemic complications.

CONCLUSIONS

Arterial involvement is rare during COVID-19 infection. The aorta and the arteries of the limbs are the privileged sites. The morbi-mortality of these patients is high. Future studies will have to determine if the systematization of anticoagulation therapy decreases the incidence and the severity of the condition.

Transplanting thoracic COVID-19 positive donors: An institutional protocol and report of the first 14 cases

We present our institution's protocol for evaluating and transplanting thoracic organs from COVID-19 positive donors and report the outcomes to date. Hearts from donors testing positive for COVID-19 on any test were eligible for transplantation at our institution provided the donor exhibited no evidence of hypercoagulability or COVID-19 induced hyperinflammatory state during terminal hospitalization. Lungs were eligible if the donor first tested PCR positive on nasopharyngeal swab (NPS) for COVID-19 > 20 days prior to procurement and had a negative lower respiratory tract specimen. We performed 14 thoracic transplants in 13 recipients using organs from COVID-19 positive donors. None of the recipients or healthcare members acquired COVID-19. No recipients suffered unexpected acute rejection. Patient survival is 92% to date, with graft survival 93%. The use of hearts from COVID-19 positive donors may be safe and effective. Transplantation of lungs is unresolved but may be cautiously pursued under the restricted circumstances.

High risk of secondary infections following thrombotic complications in patients with COVID-19

Background

This study’s primary aim was to evaluate the impact of thrombotic complications on the development of secondary infections. The secondary aim was to compare the etiology of secondary infections in patients with and without thrombotic complications.

Methods

This was a cohort study (NCT04318366) of coronavirus disease 2019 (COVID-19) patients hospitalized at IRCCS San Raffaele Hospital between February 25 and June 30, 2020. Incidence rates (IRs) were calculated by univariable Poisson regression as the number of cases per 1000 person-days of follow-up (PDFU) with 95% confidence intervals. The cumulative incidence functions of secondary infections according to thrombotic complications were compared with Gray's method accounting for competing risk of death. A multivariable Fine-Gray model was applied to assess factors associated with risk of secondary infections.

Results

Overall, 109/904 patients had 176 secondary infections (IR, 10.0; 95% CI, 8.8–11.5; per 1000-PDFU). The IRs of secondary infections among patients with or without thrombotic complications were 15.0 (95% CI, 10.7–21.0) and 9.3 (95% CI, 7.9–11.0) per 1000-PDFU, respectively (P = .017). At multivariable analysis, thrombotic complications were associated with the development of secondary infections (subdistribution hazard ratio, 1.788; 95% CI, 1.018–3.140; P = .043). The etiology of secondary infections was similar in patients with and without thrombotic complications.

Conclusions

In patients with COVID-19, thrombotic complications were associated with a high risk of secondary infections.

Analysis of post COVID-19 condition and its overlap with myalgic encephalomyelitis/chronic fatigue syndrome

BACKGROUND

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) disease (COVID-19) triggers the development of numerous pathologies and infection-linked complications and exacerbates existing pathologies in nearly all body systems. Aside from the primarily targeted respiratory organs, adverse SARS-CoV-2 effects were observed in nervous, cardiovascular, gastrointestinal/metabolic, immune, and other systems in COVID-19 survivors. Long-term effects of this viral infection have been recently observed and represent distressing sequelae recognised by the World Health Organisation (WHO) as a distinct clinical entity defined as post-COVID-19 condition. Considering the pandemic is still ongoing, more time is required to confirm post COVID-19 condition diagnosis in the COVID-19 infected cohorts, although many reported post COVID-19 symptoms overlap with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS).

AIMS OF REVIEW

In this study, COVID-19 clinical presentation and associated post-infection sequelae (post-COVID-19 condition) were reviewed and compared with ME/CFS symptomatology.

KEY SCIENTIFIC CONCEPTS OF REVIEW

The onset, progression, and symptom profile of post COVID-19 condition patients have considerable overlap with ME/CFS. Considering the large scope and range of pro-inflammatory effects of this virus, it is reasonable to expect development of post COVID-19 clinical complications in a proportion of the affected population. There are reports of a later debilitating syndrome onset three months post COVID-19 infection (often described as long-COVID-19), marked by the presence of fatigue, headache, cognitive dysfunction, post-exertional malaise, orthostatic intolerance, and dyspnoea. Acute inflammation, oxidative stress, and increased levels of interleukin-6 (IL-6) and tumor necrosis factor α (TNFα), have been reported in SARS-CoV-2 infected patients. Longitudinal monitoring of post COVID-19 patients is warranted to understand the long-term effects of SARS-CoV-2 infection and the pathomechanism of post COVID-19 condition.

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.

SARS-CoV-2 Infection-Associated Aortic Thrombosis Treated with Oral Factor Xa Inhibition

Coronavirus disease 2019 (COVID-19) is an acute complex systemic disorder caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).While SARS-CoV-2 is known to cause significant pulmonary disease, various extrapulmonary manifestations of COVID-19 have also been reported. Growing evidence suggests that COVID-19 is associated with coagulopathy leading to micro and macrovascular complications. Although in patients with COVID-19, venous thromboembolic events are more frequent, arterial thrombosis also occurs at an increased rate. These often lead to acute life-threatening ischemia, which requires urgent diagnosis and treatment. We present case reports of two patients with an abnormal thrombus formation in the thoracic aorta who recently overcame COVID-19, which led to systemic embolism and splenic infarction. Ambulatory oral factor Xa inhibitor therapy led to aortic thrombosis resolution in both patients.

Effect of therapeutic versus prophylactic anticoagulation therapy on clinical outcomes in COVID-19 patients: a systematic review with an updated meta-analysis

Background

Previous studies demonstrate a reduced risk of thrombosis and mortality with anticoagulant treatment in patients with COVID-19 than in those without anticoagulation treatment. However, an open question regarding the efficacy and safety of therapeutic anticoagulation (T-AC) versus a lower dose, prophylaxis anticoagulation (P-AC) in COVID-19 patients is still controversial.

Methods

We systematically reviewed currently available randomized clinical trials (RCTs) and observational studies (OBs) from January 8, 2019, to January 8, 2022, and compared prophylactic and therapeutic anticoagulant treatment in COVID-19 patients. The primary outcomes were risk of mortality, major bleeding, and the secondary outcomes included venous and arterial thromboembolism. Subgroup analysis was also performed between critically ill and non-critically ill patients with COVID-19 and between patients with higher and lower levels of D-dimer. Sensitivity analysis was performed to decrease the bias and the impact of population heterogeneity.

Results

We identified 11 RCTs and 17 OBs fulfilling our inclusion criteria. In the RCTs analyses, there was no statistically significant difference in the relative risk of mortality between COVID-19 patients with T-AC treatment and those treated with P-AC (RR 0.95, 95% CI, 0.78–1.15, P = 0.60). Similar results were also found in the OBs analyses (RR 1.21, 95% CI, 0.98–1.49, P = 0.08). The pooling meta-analysis using a random-effects model combined with effect sizes showed that in the RCTs and OBs analyses, patients with COVID-19 who received T-AC treatment had a significantly higher relative risk of the major bleeding event than those with P-AC treatment in COVID-19 patients (RCTs: RR 1.76, 95% CI, 1.19–2.62, P = 0.005; OBs: RR 2.39, 95% CI, 1.56–3.68, P < 0.0001). Compared with P-AC treatment in COVID-19 patients, patients with T-AC treatment significantly reduced the incidence of venous thromboembolism (RR 0.51, 95% CI, 0.39–0.67, P<0.00001), but it is not associated with arterial thrombosis events (RR 0.97, 95% CI, 0.66–1.42, P = 0.87). The subgroup analysis of OBs shows that the mortality risk significantly reduces in critically ill COVID-19 patients treated with T-AC compared with those with P-AC treatment (RR 0.58, 95% CI, 0.39–0.86, P = 0.007), while the mortality risk significantly increases in non-critically ill COVID-19 patients treated with T-AC (RR 1.56, 95% CI, 1.34–1.80, P < 0.00001). In addition, T-AC treatment does not reduce the risk of mortality in COVID-19 patients with high d-dimer levels in RCTs. Finally, the overall sensitivity analysis after excluding two RCTs studies remains consistent with the previous results.

Conclusions

In our integrated analysis of included RCTs and OBs, there is no significant difference between the mortality of T-AC and P-AC treatment in unselected patients with COVID-19. T-AC treatment in COVID-19 patients significantly reduced the incidence of venous thromboembolism but showed a higher risk of bleeding than those with P-AC treatment. In addition, P-AC treatment was superior to T-AC treatment in non-critically ill COVID-19 patients, the evidence supporting the necessity for T-AC treatment in critically ill COVID-19 patients came only from OBs.

Trial registration

Protocol registration: The protocol was registered at PROSPERO (CRD42021293294).

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12959-022-00408-9.

Endothelial Glycocalyx Degradation in Critical Illness and Injury

The endothelial glycocalyx is a gel-like layer on the luminal side of blood vessels that is composed of glycosaminoglycans and the proteins that tether them to the plasma membrane. Interest in its properties and function has grown, particularly in the last decade, as its importance to endothelial barrier function has come to light. Endothelial glycocalyx studies have revealed that many critical illnesses result in its degradation or removal, contributing to endothelial dysfunction and barrier break-down. Loss of the endothelial glycocalyx facilitates the direct access of immune cells and deleterious agents (e.g., proteases and reactive oxygen species) to the endothelium, that can then further endothelial cell injury and dysfunction leading to complications such as edema, and thrombosis. Here, we briefly describe the endothelial glycocalyx and the primary components thought to be directly responsible for its degradation. We review recent literature relevant to glycocalyx damage in several critical illnesses (sepsis, COVID-19, trauma and diabetes) that share inflammation as a common denominator with actions by several common agents (hyaluronidases, proteases, reactive oxygen species, etc.). Finally, we briefly cover strategies and therapies that show promise in protecting or helping to rebuild the endothelial glycocalyx such as steroids, protease inhibitors, anticoagulants and resuscitation strategies.

A Prospective Study on Risk Factors for Acute Kidney Injury and All-Cause Mortality in Hospitalized COVID-19 Patients From Tehran (Iran)

Background

Several reports suggested that acute kidney injury (AKI) is a relatively common occurrence in hospitalized COVID-19 patients, but its prevalence is inconsistently reported across different populations. Moreover, it is unknown whether AKI results from a direct infection of the kidney by SARS-CoV-2 or it is a consequence of the physiologic disturbances and therapies used to treat COVID-19. We aimed to estimate the prevalence of AKI since it varies by geographical settings, time periods, and populations studied and to investigate whether clinical information and laboratory findings collected at hospital admission might influence AKI incidence (and mortality) in a particular point in time during hospitalization for COVID-19.

Methods

Herein we conducted a prospective longitudinal study investigating the prevalence of AKI and associated factors in 997 COVID-19 patients admitted to the Baqiyatallah general hospital of Tehran (Iran), collecting both clinical information and several dates (of: birth; hospital admission; AKI onset; ICU admission; hospital discharge; death). In order to examine how the clinical factors influenced AKI incidence and all-cause mortality during hospitalization, survival analysis using the Cox proportional-hazard models was adopted. Two separate multiple Cox regression models were fitted for each outcome (AKI and death).

Results

In this group of hospitalized COVID-19 patients, the prevalence of AKI was 28.5% and the mortality rate was 19.3%. AKI incidence was significantly enhanced by diabetes, hyperkalemia, higher levels of WBC count, and blood urea nitrogen (BUN). COVID-19 patients more likely to die over the course of their hospitalization were those presenting a joint association between ICU admission with either severe COVID-19 or even mild/moderate COVID-19, hypokalemia, and higher levels of BUN, WBC, and LDH measured at hospital admission. Diabetes and comorbidities did not increase the mortality risk among these hospitalized COVID-19 patients.

Conclusions

Since the majority of patients developed AKI after ICU referral and 40% of them were admitted to ICU within 2 days since hospital admission, these patients may have been already in critical clinical conditions at admission, despite being affected by a mild/moderate form of COVID-19, suggesting the need of early monitoring of these patients for the onset of eventual systemic complications.

Longwise Cluster Analysis for the Prediction of COVID-19 Severity within 72 h of Admission: COVID-DATA-SAVE-LIFES Cohort

The use of routine laboratory biomarkers plays a key role in decision making in the clinical practice of COVID-19, allowing the development of clinical screening tools for personalized treatments. This study performed a short-term longitudinal cluster from patients with COVID-19 based on biochemical measurements for the first 72 h after hospitalization. Clinical and biochemical variables from 1039 confirmed COVID-19 patients framed on the “COVID Data Save Lives” were grouped in 24-h blocks to perform a longitudinal k-means clustering algorithm to the trajectories. The final solution of the three clusters showed a strong association with different clinical severity outcomes (OR for death: Cluster A reference, Cluster B 12.83 CI: 6.11−30.54, and Cluster C 14.29 CI: 6.66−34.43; OR for ventilation: Cluster-B 2.22 CI: 1.64−3.01, and Cluster-C 1.71 CI: 1.08−2.76), improving the AUC of the models in terms of age, sex, oxygen concentration, and the Charlson Comorbidities Index (0.810 vs. 0.871 with p < 0.001 and 0.749 vs. 0.807 with p < 0.001, respectively). Patient diagnoses and prognoses remarkably diverged between the three clusters obtained, evidencing that data-driven technologies devised for the screening, analysis, prediction, and tracking of patients play a key role in the application of individualized management of the COVID-19 pandemics.

Double Trouble: Interrupting DAPT and COVID-19

Cardiovascular disorders have been described as relevant risk factor for severe COVID infection. Stent thrombosis is a life-threatening complication that may occur subacutely. We present an interesting case of a middle-aged woman who developed acute stent thrombosis while interrupting dual antiplatelet therapy (DAPT) ticagrelor, during an episode of coronavirus disease (COVID-19). In our case, the patient’s not-compliance to DAPT, associated with COVID-19 infection and a hyperinflammatory and hypercoagulable state associated with it played a major role in the development of stent thrombosis. The hypercoagulable and hyperinflammatory state associated with COVID-19 has important implications for cardiac patients, especially those undergoing complex coronary intervention, predisposing them to an increased risk of post-PCI complications.

Anticoagulation for left ventricular thrombi secondary to COVID —Is 3 months too long?

The length of anticoagulation for thrombotic events related to COVID‐19 is unknown. We present a patient with COVID‐19 complicated by a thrombotic anterior STEMI and multiple left ventricular (LV) thrombi that resolved after 8 weeks of anticoagulation. We suggest a shorter length of anticoagulation with COVID‐19‐related LV thrombus.

Cardiac Thromboembolism in COVID-19: A Case Series

Venous thromboembolism (VTE) is a very common complication of coronavirus disease-2019 (COVID-19) because of the acquired hypercoagulability in these patients. Cardiovascular thromboembolism (CTE) is another complication that is relatively rare yet catastrophic. We present two cases of COVID-19 which were complicated by CTE. Case one describes a 55-year-old male with COVID-19 who had an ST-segment elevation myocardial infarction (STEMI) secondary to coronary artery embolism and was also found to have biventricular thrombi (BVT). Case two describes a 65-year-old female presenting with STEMI secondary to coronary artery embolism. This document highlights how CTE can be present in COVID-19 patients and describes the available evidence for its management. Given the paucity of data on these complications, we illustrate the offered treatment which was based on the data extrapolated from the treatment of VTE in COVID-19 and the treatment of CTE in non-COVID-19 patients.

Venous Thromboembolism and COVID-19-an Epidemiological Perspective

The coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was declared as pandemic by World Health Organization (WHO) in March 2020. The outbreak has caused 5,232,562 deaths worldwide until December 3rd, 2021. Though primarily affecting the respiratory system, involvement of other organ systems have been reported in severe disease. Venous thromboembolism (VTE) has been recognized as an important complication. Previous studies have reported the prevalence of VTE in intensive care unit (ICU) patients between 7 and 85% and in non-ICU patients between 0 and 19%. COVID-19 patients that are at high risk for VTE are also at increased risk for bleeding. In such cases, anticoagulation may potentially be harmful. Thereby, it is important to understand the risk factors for VTE predisposition in the COVID-19 patients, timing of VTE, and the rate of occurrence of VTE in hospitalized patients post-discharge. Comparison of the rate of occurrence of VTE in COVID-19 patients with the non-COVID-19 patients with similar disease severity is required to truly interpret the reportedly high rates of VTE in COVID-19 patients. Several pathophysiological mechanisms have been reported for the development of VTE in COVID-19. Autopsy-based studies have contributed to the existing knowledge. d-dimer, presently, seems to be the most suitable investigation for risk-identification of VTE supported by Doppler studies and overall clinical context. Further, prospective studies and clinical trials are essentially required to fill the gaps in evidence for occurrence, risk prediction and management of VTE in COVID-19 patients.

Evaluation of soluble fibrin monomer complex in patients in SARS-CoV-2 COVID-19 infection-associated coagulopathy

Hospitalized patients with COVID-19 infection frequently have coagulopathy resembling disseminated intravascular coagulation (DIC). An elevation of D-dimer level is associated with a poor prognosis; however, the role of other fibrin degradation products, such as soluble fibrin monomers (SFMC), is not known. The objective of the study was to investigate the frequency and prognostic role of elevated SFMC in patients with COVID-19. In this retrospective cohort study, patients hospitalized between April 1, 2020 and December 14, 2020 at Mayo Clinic with COVID-19 infection who underwent DIC panel testing were identified. Results of laboratory tests and outcomes (thrombosis and death) within 40 days of testing were obtained via medical record review. Of 108 patients, D-dimer was elevated in 82 (75.9%) patients. Of those with elevated D-dimer, SFMC was elevated in 19/82 (23%) patients. There were 16 thrombotic events and 16 deaths during the 40-day follow-up. The incidence of overt-DIC was 4.6%. In univariate analysis, D-dimer ≥5 x highest upper limit normal (ULN) and elevated SFMC were each associated with higher 40-day mortality. However, when used in combination with D-dimer ≥5 x highest ULN, an elevated SFMC provided no further mortality predictive value. Compared to 75.9% of patients with elevated D-dimers, of those tested, only 23% had elevated SFMC. These results support the hypothesis that elevated D-dimer in COVID-19 infection is a direct consequence of endothelial damage and not overt-DIC.

Cardiovascular Dysfunction in COVID-19: Association Between Endothelial Cell Injury and Lactate

Coronavirus disease 2019 (COVID-19), an infectious respiratory disease propagated by a new virus known as Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), has resulted in global healthcare crises. Emerging evidence from patients with COVID-19 suggests that endothelial cell damage plays a central role in COVID-19 pathogenesis and could be a major contributor to the severity and mortality of COVID-19. Like other infectious diseases, the pathogenesis of COVID-19 is closely associated with metabolic processes. Lactate, a potential biomarker in COVID-19, has recently been shown to mediate endothelial barrier dysfunction. In this review, we provide an overview of cardiovascular injuries and metabolic alterations caused by SARS-CoV-2 infection. We also propose that lactate plays a potential role in COVID-19-driven endothelial cell injury.

Efficacy and Safety of Complementary Therapy With Jing Si Herbal Tea in Patients With Mild-To-Moderate COVID-19: A Prospective Cohort Study

Background

Since late 2019, there has been a global COVID-19 pandemic. To preserve medical capacity and decrease adverse health effects, preventing the progression of COVID-19 to severe status is essential. Jing-Si Herbal Tea (JSHT), a novel traditional Chinese medicine formula was developed to treat COVID-19. This study examined the clinical efficacy and safety of JSHT in patients with mild-to-moderate COVID-19.

Methods

In this prospective cohort study, we enrolled 260 patients with mild-to-moderate COVID-19. The enrolled patients were divided into the JSHT (n = 117) and control (n = 143) groups. Both groups received standard management. The JSHT group was treated with JSHT as a complementary therapy.

Results

Compared with standard management alone, JSHT combined with standard management more effectively improved the reverse transcription–polymerase chain reaction cycle threshold value, C-reactive protein level, and Brixia score in the adult patients with mild-to-moderate COVID-19, especially in the male and older patients (those aged ≥60 years). The results revealed that the patients treated with JSHT combined with standard management had 51, 70, and 100% lower risks of intubation, Medisave Care Unit admission, and mortality compared with those receiving standard management only.

Conclusions

JSHT combined with standard management more effectively reduced the SARS-CoV-2 viral load and systemic inflammation and alleviated lung infiltrates in the patients with mild-to-moderate COVID-19, especially in the male and older patients (those aged ≥60 years). JSHT combined with standard management may prevent critical status and mortality in patients with mild-to-moderate COVID-19. JSHT is a promising complementary therapy for patients with mild-to-moderate COVID-19.