Thromboembolic prevention and anticoagulant therapy during the COVID-19 pandemic: updated clinical guidance from the anticoagulation forum

Examining the role of thromboelastography in patients with COVID-19

BackgroundCOVID-19 causes a severe respiratory distress syndrome. Systemic inflammation and hypercoagulability are common. These findings are often evaluated with non-specific markers, including CRP, D-dimer, and fibrinogen. We sought to evaluate thromboelastography (TEG) to better understand this complex coagulopathy.MethodsWe conducted a prospective observational study analyzing TEG results in hospitalized patients with COVID-19. TEG was performed on admission and at pre-set intervals. Based on the TEG findings, patients were deemed "hypercoagulable" or "not hypercoagulable." Clinical outcomes were recorded.Results88 patients were evaluated. 78/88 (89%) were hypercoagulable. 10% of the hypercoagulable group (8/78) died compared to none in the non-hypercoagulable group (0/10), with thrombotic events occurring in 9% (8/88), a higher requirement for O2 support in 19% (17/88), and prolonged length of stay exceeding 4 days for 74% (65/88). No statistical significant differences were observed between the groups for any of the four adverse events. Patients with complete fibrinolysis shutdown (Ly30 = 0) had more thrombotic events than those with Ly30 > 0 (30% vs 0%, p = .03).ConclusionPatients with COVID-19 are often hypercoagulable based upon specific TEG parameters. While many TEG parameters are not associated with adverse outcomes, complete fibrinolysis shutdown is associated with an increased risk of thrombotic events. Further studies are warranted to assess the utility of TEG in this population.

Comprehensive DVT risk assessment model for meningioma surgery: development, validation and clinical implementation

Deep vein thrombosis (DVT) represents a significant complication in meningioma surgery, with reported incidence rates of 10-30%. Current predictive models demonstrate limited accuracy in this specific population, necessitating the development of more precise risk assessment tools. In this single-center retrospective cohort study (2019-2024), we analyzed 126 patients who underwent meningioma surgery, equally distributed between DVT and control groups. Multiple regression analysis was used to develop a predictive model incorporating clinical, laboratory, and surgical parameters. The model was validated using bootstrap resampling with 1000 iterations. Primary outcome was ultrasonography-confirmed DVT. The model achieved superior discrimination (derivation cohort: AUC = 0.83, 95% CI: 0.78-0.89; validation cohort: AUC = 0.81, 95% CI: 0.75-0.87) compared to existing risk assessment tools. Independent predictors included preoperative platelet count > 400,000/µL (OR: 3.4, 95% CI: 2.1-5.8), D-dimer > 1000ng/mL (OR: 3.0, 95% CI: 2.0-4.8), prolonged immobility > 48 h (OR: 2.7, 95% CI: 1.6-4.4), tumor size > 4 cm (OR: 2.3, 95% CI: 1.5-3.7), and extended surgical duration > 180 min (OR: 2.1, 95% CI: 1.4-3.5). Model implementation resulted in significant reductions in unnecessary screening (28%) and prophylactic anticoagulation use (35%), with demonstrated overall cost savings of 42% per patient. This comprehensive risk assessment model demonstrates robust predictive accuracy for post-operative DVT in meningioma patients, offering significant improvements in risk stratification and resource utilization. The model's strong discrimination and successful validation support its implementation in clinical practice.

Beyond the guidelines: original research on real-world outcomes of anticoagulation and corticosteroid in COVID-19

BACKGROUND

The COVID-19 pandemic has led to the widespread use of anticoagulation (AC) and corticosteroids (CCS) for hospitalized patients, but real-world outcomes may differ from clinical trial findings due to diverse patient populations and treatment variability.

OBJECTIVE

To evaluate the real-world impact of AC and CCS therapies on key clinical outcomes in hospitalized COVID-19 patients.

DESIGN

Multicenter, retrospective observational cohort study conducted across 11 hospitals in a Midwest health system.

PARTICIPANTS

The study included 4754 hospitalized COVID-19 patients treated with AC, CCS, both (AC+CCS), or neither. The 'neither' group served as the reference for comparisons.

INTERVENTIONS

Interventions included administration of AC, CCS, both AC+CCS, or no intervention.

MAIN MEASURES

Primary outcomes included thromboembolism (TE), bleeding events, ICU admissions, invasive mechanical ventilation (IMV), and in-hospital mortality.

KEY RESULTS

Compared to the reference group, the AC+CCS group had significantly lower odds of TE (aOR 0.61, 95% CI 0.43-0.87) and bleeding events (aOR 0.15 95% CI (0.08, 0.27)). The AC-only group demonstrated the lowest ICU admission, IMV, and mortality rates (aHR 0.30 95% CI (0.17, 0.53)). The CCS-only group had the highest rates of adverse outcomes, likely reflecting greater baseline illness severity.

CONCLUSIONS

This study emphasizes the importance of individualized treatment strategies in hospitalized COVID-19 patients, showing that real-world outcomes of AC and CCS can differ significantly from controlled trials. These findings provide crucial insights for adapting clinical guidelines to diverse patient settings.

Trends in the Diagnosis of Pediatric Venous Thromboembolism and Arterial Ischemic Stroke during the COVID-19 Pandemic: An Administrative Database Study

OBJECTIVE

To investigate trends in the diagnosis of venous thromboembolism (VTE) and arterial ischemic stroke (AIS), and examine the use of pharmacological thromboprophylaxis during the COVID-19 pandemic.

STUDY DESIGN

This retrospective cohort study used the Pediatric Health Information Systems database to investigate patients admitted to a participating hospital between January 1, 2018, and December 31, 2021. International Classification of Diseases, 10th edition codes were used to identify VTE, AIS, and COVID-19. Pharmacy billing codes were used to investigate pharmacological thromboprophylaxis use.

RESULTS

1 759 701 unique patients underwent 2 234 135 inpatient admissions. Rate of VTE increased from 84 cases per 10 000 admissions in 2018-2019 to 108 cases per 10 000 admissions in 2020-2021, representing a 28.6% increase (P < .001). In contrast, the rate of AIS remained stable through the study period. When compared with 2018-2019, children diagnosed with VTE during 2020-2021 had longer hospitalizations and were more likely to be admitted to the intensive care unit. When analysis was limited to 2020-2021, a diagnosis code of COVID-19 was associated with a 1.35-fold (95% CI: 1.24-1.45) increase in the odds of VTE diagnosis, but not AIS. Use of pharmacologic thromboprophylaxis increased from 1.5% of hospitalizations in 2018-2019 to 3.0% of hospitalizations in 2020-2021 (P < .001). When evaluating thromboprophylaxis during 2020-2021, a diagnosis code for COVID-19 was associated with an 11-fold (95% CI: 10.86-11.49; P < .001) increase in the utilization of pharmacological thromboprophylaxis.

CONCLUSIONS

This study found an increase in the rate of VTE among hospitalized children during the pandemic. A diagnosis of COVID-19 was associated with a modest increase in odds of VTE diagnosis, which occurred despite increased use of pharmacological thromboprophylaxis.

Incidence and risk of post-COVID-19 thromboembolic disease and the impact of aspirin prescription; nationwide observational cohort at the US Department of Veteran Affairs

INTRODUCTION

COVID-19 triggers prothrombotic and proinflammatory changes, with thrombotic disease prevalent in up to 30% SARS-CoV-2 infected patients. Early work suggests that aspirin could prevent COVID-19 related thromboembolic disorders in some studies but not others. This study leverages data from the largest integrated healthcare system in the United States to better understand this association. Our objective was to evaluate the incidence and risk of COVID-19 associated acute thromboembolic disorders and the potential impact of aspirin.

METHODS

This retrospective, observational study utilized national electronic health record data from the Veterans Health Administration. 334,374 Veterans who tested positive for COVID-19 from March 2, 2020, to June 13, 2022, were included, 81,830 of whom had preexisting aspirin prescription prior to their COVID-19 diagnosis. Patients with and without aspirin prescriptions were matched and the odds of post-COVID acute thromboembolic disorders were assessed.

RESULTS

10.1% of Veterans had a documented thromboembolic disorder within 12 months following their COVID-19 diagnosis. Those with specific comorbidities were at greatest risk. Preexisting aspirin prescription was associated with a significant decrease risk of post-COVID-19 thromboembolic disorders, including pulmonary embolism (OR [95% CI]: 0.69 [0.65, 0.74]) and deep vein thrombosis (OR [95% CI]: 0.76 [0.69, 0.83], but an increased risk of acute arterial diseases, including ischemic stroke (OR [95% CI]: 1.54 [1.46, 1.60]) and acute ischemic heart disease (1.33 [1.26, 1.39]).

CONCLUSIONS

Findings demonstrated that preexisting aspirin prescription prior to COVID-19 diagnosis was associated with significantly decreased risk of venous thromboembolism and pulmonary embolism but increased risk of acute arterial disease. The risk of arterial disease may be associated with increased COVID-19 prothrombotic effects superimposed on preexisting chronic cardiovascular disease for which aspirin was already prescribed. Prospective clinical trials may help to further assess the efficacy of aspirin use prior to COVID-19 diagnosis for the prevention of post-COVID-19 thromboembolic disorders.

Comparison of the Efficacy and Safety of Low Molecular Weight Heparins and Fondaparinux in Patients With COVID-19: A Systematic Review and Meta-Analysis

Individuals diagnosed with COVID-19 are at a higher risk of arterial and venous thrombosis, mostly pulmonary microvascular thrombosis, which may significantly impair treatment and result in morbidity. This is a systematic review and meta-analysis of research papers that aim to evaluate the risk of bleeding and thrombosis among patients treated with low molecular weight heparin or fondaparinux (LMWH/F). Additionally, we measured the overall death events. This study was conducted in compliance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria. A search was conducted in the Clinicaltrials.gov, PubMed, Scopus, and Web of Science databases to identify observational cohort studies and randomized-controlled clinical trials (RCTs) that compared LMWH/F in proven COVID-19 patients. A total of 220 people from two studies were included. Patients who were treated with fondaparinux had a lower risk of developing venous thromboembolism (VTE) (odds ratio (OR) 0.39; 95% confidence interval (CI) (0.14, 1.096); p = 0.168); pulmonary embolism (OR 0.169, 95% CI (0.021, 1.356), p = 0.094); and deep vein thrombosis compared to patients who received LMWH therapy. The data show a lower mortality rate in the LMWH groups (OR 1.135, 95% CI (0.463, 2.785), p = 0.781) and a lower frequency of bleeding (OR 1.657, 95% CI (0.456, 5.908), p = 0.436). Both drugs have shown anti-thrombotic properties in COVID-19 patients. Fondaparinux was somewhat more effective in reducing thrombosis episodes. This research demonstrates the safe use of LMWH for VTE prophylaxis in hospitalized COVID-19 patients based on bleeding and mortality outcomes.

COVID-19 Coagulopathy

Coronavirus disease of 2019 (COVID-19) is the respiratory viral infection caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Despite being a primary respiratory illness, it is commonly complicated by systemic involvement of the vasculature leading to arterial and venous thrombosis. In this review, we will focus on the association between COVID-19 and thrombosis. We will highlight the pathophysiology of COVID-19 coagulopathy. The clinical manifestations of COVID-19 vasculopathy will be discussed with a focus on venous and arterial thromboembolic events. COVID-19 vasculopathy and disseminated intravascular coagulation (DIC) are distinguished within, as well as areas of controversy, such as "long COVID". Finally, the current professional guidelines on prevention and treatment of thrombosis associated with SARS-CoV-2 infection will be discussed.

Factor Xa inhibitors versus low-molecular-weight heparin for preventing coagulopathy following COVID-19: a systematic review and meta-analysis of randomized controlled trials

Background

Hospitalized patients with COVID-19 have shown a significant occurrence of thromboembolism and a heightened risk of death. It remains unclear whether factor Xa inhibitors are superior to enoxaparin in this context. Hence, there is a need for a direct comparison to assess the preventive effects and safety of factor Xa inhibitors versus enoxaparin in hospitalized COVID-19 patients.

Methods

MEDLINE, Embase, and Cochrane Central databases were searched for randomized controlled trials (RCTs) or retrospective studies that compared the effectiveness or safety of factor Xa inhibitors and enoxaparin in preventing thromboembolism in hospitalized patients with COVID-19. Embolic incidence, incidence of bleeding, and all-cause mortality were among the outcomes of interest. Mantel-Haenszel weighted random-effects model was used to calculate relative risks (RRs) with 95 percent CIs.

Results

The analysis included six RCTs and two retrospective studies containing 4048 patients. Meta-analysis showed a statistically significant reduction among patients on factor Xa inhibitors compared with low-molecular-weight heparin (LMWH) in the embolic incidence [risk ratio (RR) 0.64 (95%, CI 0.42, 0.98); P=0.04, I2=12%]. Upon subgroup analysis by type of study design, no significant reductions were noted in patients on factor Xa inhibitors in RCTs (RR: 0.62; 95% CI: 0.33-1.17; P=0.14) or observational studies (RR: 0.53; 95% CI: 0.23-1.26; P=0.15) when compared with enoxaparin Factor Xa inhibitors were not significantly associated with incidence of bleeding [RR 0.76 (95% CI 0.36, 1.61); P=0.47, I2=0%] or all-cause mortality (RR: 0.81; 95% CI: 0.48-1.36; P=0.43). Consistent results were obtained upon subgroup analysis by the type of study design.

Conclusion

Factor Xa inhibitors are more effective than enoxaparin in preventing thromboembolism among patients with COVID-19 who are not acutely ill and are hospitalized. Additional rigorous RCTs comparing factor Xa inhibitors with enoxaparin are warranted.

Appropriate thromboprophylaxis strategy for COVID-19 patients on dosage, antiplatelet therapy, outpatient, and postdischarge prophylaxis: a meta-analysis of randomized controlled trials

BACKGROUND

There was controversy surrounding the optimal thromboprophylaxis strategy for coronavirus disease 2019 (COVID-19) patients. This included debates on the dosage of anticoagulants for thromboembolism prophylaxis, the requirement for additional antiplatelet therapy, and the necessity of prophylaxis for outpatients and postdischarge. To explore this, the authors performed a meta-analysis of randomized controlled trials.

METHODS

PubMed, Cochrane Library, Embase, and Web of Science were last searched on 26 July 2023 for studies comparing the effect of different dose of anticoagulation, additional antiplatelet, and postdischarge prophylaxis for COVID-19 patients. The results of eligible studies were analyzed in terms of thromboembolism events, major bleeding and all-cause mortality during follow-up.

RESULTS

Our study included a total of 25 randomized controlled trials, involving 17 911 patients. Our results revealed that, compared to prophylactic dose, therapeutic dose showed lower thrombotic risk (RR, 0.66; 95% CI: 0.45-0.96) but had similar major bleeding risk for critically ill patients with COVID-19. On the other hand, intermediate dose and prophylactic dose demonstrated similar thromboembolism risk and major bleeding risk. For noncritically ill patients with COVID-19, therapeutic dose of anticoagulants was associated with lower thrombotic risk (RR, 0.50; 95% CI: 0.34-0.72) but, at the same time, increased the risk of major bleeding (RR, 2.01; 95% CI: 1.22-3.33). However, intermediate dose showed lower thromboembolism risk (RR, 0.38; 95% CI: 0.21-0.69) while maintaining a similar major bleeding risk. In critically ill patients, additional antiplatelet therapy showed similar thromboembolism, major bleeding risk, and mortality when compared to no treatment. For outpatients, additional prophylactic anticoagulation showed similar thromboembolism, major bleeding risk, and mortality when compared to no treatment. For postdischarge patients, postdischarge prophylaxis reduced thromboembolism risk (RR, 0.49; 95% CI: 0.31-0.76) but increased major bleeding risk (RR, 2.63; 95% CI: 1.13-6.14).

CONCLUSION

For noncritically ill patients, therapeutic dose prophylactic anticoagulation significantly reduced venous thromboembolism but increases major bleeding risk. Intermediate dose effectively lowered venous thromboembolism without raising major bleeding risk. The optimal dose and need for additional antiplatelet therapy in critically ill patients, as well as the necessity of prophylactic anticoagulation in outpatient and postdischarge patients, required further investigation and confirmation through rigorous evidence studies.

Evaluating thromboprophylaxis in the sickle cell disease population: Navigating the evidence gap

Sickle cell disease (SCD) arises from beta-globin gene mutations, with global estimates indicating around 500 000 affected neonates in 2021. In the United States, it is considered rare, impacting fewer than 200 000 individuals. The key pathogenic flaw lies in mutant haemoglobin S, prone to polymerization under low oxygen conditions, causing erythrocytes to adopt a sickled shape. This leads to complications like vascular occlusion, haemolytic anaemia, inflammation and organ damage. Beyond erythrocyte abnormalities however, there is a body of literature highlighting the hypercoagulable state that is likely a contributor to many of the complications we see in SCD. The persistent activation of the coagulation cascade results in thromboembolic events, notably venous thromboembolism (VTE) which is independently associated with increased mortality in both adults and children with SCD. While the increased risk of VTE in the SCD population seems well established, there is a lack of guidelines for thromboprophylaxis in this population. This Wider Perspective will describe the hypercoagulable state and increased thrombosis risk in the SCD population, as well as advocate for the development of evidence-based guidelines to aid in the prevention of VTE in SCD.

Enhancing deep vein thrombosis prediction in patients with coronavirus disease 2019 using improved machine learning model

BACKGROUND

Deep vein thrombosis (DVT) is a significant complication in coronavirus disease 2019 patients, arising from coagulation issues in the deep venous system. Among 424 scheduled patients, 202 developed DVT (47.64%). DVT increases hospitalization risk, and complications, and impacts prognosis. Accurate prognostication and timely intervention are crucial to prevent DVT progression and improve patient outcomes.

METHODS

This study introduces an effective DVT prediction model, named bSES-AC-RUN-FKNN, which integrates fuzzy k-nearest neighbor (FKNN) with enhanced Runge-Kutta optimizer (RUN). Recognizing the insufficient effectiveness of RUN in local search capability and its convergence accuracy, spherical evolutionary search (SES) and differential evolution-inspired knowledge adaptive crossover (AC) are incorporated, termed SES-AC-RUN, to enhance its optimization capability.

RESULTS

Based on the benchmark set by CEC 2017 and comparative analyses with several peers, it is evident that SES-AC-RUN significantly enhances search performance compared to traditional RUN, even standing comparably against leading championship algorithms. The proposed bSES-AC-RUN-FKNN model was applied to predict a dataset comprising 424 cases of DVT patients, totaling 7208 records. Remarkably, the model demonstrates outstanding accuracy, reaching 91.02%, alongside commendable sensitivity at 91.07%.

CONCLUSIONS

The bSES-AC-RUN-FKNN emerges as a robust and efficient predictive tool, significantly enhancing the accuracy of DVT prediction. This model can be used to manage the risk of thrombosis in the care of COVID-19 patients. Nursing staff can combine the model's predictions with clinical judgment to formulate comprehensive treatment approaches.

Multidisciplinary Management Strategies for Long COVID: A Narrative Review

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused millions of infections to date and has led to a worldwide pandemic. Most patients had a complete recovery from the acute infection, however, a large number of the affected individuals experienced symptoms that persisted more than 3 months after diagnosis. These symptoms most commonly include fatigue, memory difficulties, brain fog, dyspnea, cough, and other less common ones such as headache, chest pain, paresthesias, mood changes, muscle pain, and weakness, skin rashes, and cardiac, endocrine, renal and hepatic manifestations. The treatment of this syndrome remains challenging. A multidisciplinary approach to address combinations of symptoms affecting multiple organ systems has been widely adopted. This narrative review aims to bridge the gap surrounding the broad treatment approaches by providing an overview of multidisciplinary management strategies for the most common long COVID conditions.

Chronic Anticoagulation in Patients with Atrial Fibrillation and COVID-19: A Systematic Review and Meta-Analysis

BACKGROUND

Coronavirus disease 2019 (COVID-19) is associated with hypercoagulability. It remains uncertain whether ongoing anticoagulation for atrial fibrillation (AF) in patients who later contract COVID-19 improves clinical outcomes.

OBJECTIVES

To compare chronic oral anticoagulation with no previous anticoagulation in patients with AF who contracted a COVID-19 infection concerning the outcomes of all-cause mortality, COVID-19 mortality, intensive care unit (ICU) admission, and hospitalization.

METHODS

We systematically searched PubMed, Embase, and Cochrane Library for eligible studies from inception to December 2022. We included studies comparing COVID-19 outcomes in patients with versus without prior chronic anticoagulation for AF. Risk ratios (RR) with 95% confidence intervals (CI) were pooled with a random-effects model. The level of significance was set at p < 0.05. Quality assessment and risk of bias were performed according to Cochrane recommendations.

RESULTS

Ten studies comprising 1,177,858 patients with COVID-19 and AF were identified, of whom 893,772 (75.9%) were on prior chronic anticoagulation for AF. In patients with COVID-19, being on chronic anticoagulation for AF significantly reduced all-cause mortality (RR 0.75; 95% CI 0.57 to 0.99; p = 0.048; I2 = 89%) and COVID-19-related mortality (RR 0.76; 95% CI 0.72 to 0.79; p < 0.001; I2 = 0%) when compared with no prior anticoagulation. In contrast, there was no difference between groups regarding hospitalization (RR 1.08; 95% CI 0.82 to 1.41; p = 0.587; I2 = 95%) or ICU admission (RR 0.86; 95% CI 0.68 to 1.09; p = 0.216; I2 = 69%).

CONCLUSIONS

In this meta-analysis, chronic anticoagulation for patients with AF who contracted COVID-19 was associated with significantly lower rates of all-cause mortality and COVID-19-related mortality as compared with no previous anticoagulation.

Impact of Omicron variant infection on the liver, kidney, and coagulation system in patients undergoing elective surgery: a retrospective case-control study

Purpose: We aimed to investigate the impact of Omicron variant infection on the perioperative organ function in patients undergoing elective surgery. Methods: A total of 5029 patients who underwent elective surgery between October 2022 and January 2023 at our hospital were enrolled. Among them, the patients who underwent elective surgery between October 2022 and November 2022 composed Group 1 (not infected with the Omicron variant) the control group; those who underwent elective surgery between December 2022 and January 2023 composed Group 2 (one month after Omicron variant infection) the experimental group. We further divided the patients into two subgroups for analysis: the tumor subgroup and the nontumor subgroup. Data on organ system function indicators, including coagulation parameters, liver function, complete blood count (CBC), and kidney function, were collected before and after surgery. Differences between the two groups were subsequently analyzed via binary logistic regression analysis. Results: Compared with those in the uninfected patient group, the following changes were observed in patients with Omicron variant infection who underwent elective surgery one month after infection: prothrombin activity (PTa), prothrombin time (PT), fibrinogen, albumin/globulin, alanine aminotransferase (ALT), mean corpuscular hemoglobin concentration (MCHC), platelet (PLT), and anemia were increased AST/ALT, indirect bilirubin (IBILI), eosinophils, and uric acid were decreased before surgery; and lung infection/pneumonia and fibrinogen were increased, while AST/ALT, globulin, total bilirubin (TBIL), white blood cell count (WBC), and uric acid were decreased after surgery. There was no significant difference in the mortality rate or length of hospital stay (LOS) between the two groups. Subgroup analysis revealed elevated monocyte, PLT, and fibrinogen classification, levels and decreased globulin, prealbumin (PBA), eosinophil, and uric acid levels in the tumor subgroup of patients who underwent elective surgery one month after Omicron infection compared with those in the uninfected patients. Compared with the nontumor subgroup, fibrinogen levels, lung infection/pneumonia, TBIL, and PLT count were increased in the uninfected patients, while the globulin and eosinophil levels were decreased. Conclusion: Compared with uninfected patients, patients who underwent elective surgery one month after Omicron variant infection exhibited minimal changes in perioperative coagulation parameters, liver function, CBC counts, and kidney function. Additionally, no significant differences in postoperative mortality or LOS were observed between the two groups.

Which are the optimal thromboprophylaxis strategies for hospitalized patients with COVID-19? current controversies

Novel coronavirus 2019 (COVID-19) represents a significant risk factor for the development of venous thromboembolism (VTE) in hospitalized with both moderate and severe/critical COVID-19. Herein, we present a brief updated review on emerging robust data on diverse thromboprophylaxis strategies used to mitigate VTE complications, as well as a personal point of view of current controversies in regards the use of therapeutic and prophylactic anticoagulation strategies, particularly in the moderately-ill subgroup of patients with COVID-19.

Effectiveness of Drug Repurposing and Natural Products Against SARS-CoV-2: A Comprehensive Review

The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is a betacoronavirus responsible for the COVID-19 pandemic, causing respiratory disorders, and even death in some individuals, if not appropriately treated in time. To face the pandemic, preventive measures have been taken against contagions and the application of vaccines to prevent severe disease and death cases. For the COVID-19 treatment, antiviral, antiparasitic, anticoagulant and other drugs have been reused due to limited specific medicaments for the disease. Drug repurposing is an emerging strategy with therapies that have already tested safe in humans. One promising alternative for systematic experimental screening of a vast pool of compounds is computational drug repurposing (in silico assay). Using these tools, new uses for approved drugs such as chloroquine, hydroxychloroquine, ivermectin, zidovudine, ribavirin, lamivudine, remdesivir, lopinavir and tenofovir/emtricitabine have been conducted, showing effectiveness in vitro and in silico against SARS-CoV-2 and some of these, also in clinical trials. Additionally, therapeutic options have been sought in natural products (terpenoids, alkaloids, saponins and phenolics) with promising in vitro and in silico results for use in COVID-19 disease. Among these, the most studied are resveratrol, quercetin, hesperidin, curcumin, myricetin and betulinic acid, which were proposed as SARS-CoV-2 inhibitors. Among the drugs reused to control the SARS-CoV2, better results have been observed for remdesivir in hospitalized patients and outpatients. Regarding natural products, resveratrol, curcumin, and quercetin have demonstrated in vitro antiviral activity against SARS-CoV-2 and in vivo, a nebulized formulation has demonstrated to alleviate the respiratory symptoms of COVID-19. This review shows the evidence of drug repurposing efficacy and the potential use of natural products as a treatment for COVID-19. For this, a search was carried out in PubMed, SciELO and ScienceDirect databases for articles about drugs approved or under study and natural compounds recognized for their antiviral activity against SARS-CoV-2.

Beyond the Acute Phase: Long-Term Impact of COVID-19 on Functional Capacity and Prothrombotic Risk-A Pilot Study

Background and Objectives: Assessment of the prothrombotic, proinflammatory, and functional status of a cohort of COVID-19 patients at least two years after the acute infection to identify parameters with potential therapeutic and prognostic value. Materials and Methods: We conducted a retrospective, descriptive study that included 117 consecutive patients admitted to Iasi Pulmonary Rehabilitation Clinic for reassessment and a rehabilitation program at least two years after a COVID-19 infection. The cohort was divided into two groups based on the presence (n = 49) or absence (n = 68) of pulmonary fibrosis, documented through high-resolution computer tomography. Results: The cohort comprises 117 patients, 69.23% females, with a mean age of 65.74 ± 10.19 years and abnormal body mass index (31.42 ± 5.71 kg/m2). Patients with pulmonary fibrosis have significantly higher levels of C-reactive protein (CRP) (p < 0.05), WBC (7.45 ± 7.86/mm3 vs. 9.18 ± 17.24/mm3, p = 0.053), neutrophils (4.68 ± 7.88/mm3 vs. 9.07 ± 17.44/mm3, p < 0.05), mean platelet volume (MPV) (7.22 ± 0.93 vs. 10.25 ± 0.86 fL, p < 0.05), lactate dehydrogenase (p < 0.05), and D-dimers (p < 0.05), but not ferritin (p = 0.470), reflecting the chronic proinflammatory and prothrombotic status. Additionally, patients with associated pulmonary fibrosis had a higher mean heart rate (p < 0.05) and corrected QT interval (p < 0.05). D-dimers were strongly and negatively correlated with diffusion capacity corrected for hemoglobin (DLCO corr), and ROC analysis showed that the persistence of high D-dimers values is a predictor for low DLCO values (ROC analysis: area under the curve of 0.772, p < 0.001). The results of pulmonary function tests (spirometry, body plethysmography) and the 6-minute walk test demonstrated no significant difference between groups, without notable impairment within either group. Conclusions: Patients with COVID-19-related pulmonary fibrosis have a persistent long-term proinflammatory, prothrombotic status, despite the functional recovery. The persistence of elevated D-dimer levels could emerge as a predictive factor associated with impaired DLCO.

It's in the blood: a review of the hematological system in SARS-CoV-2-associated COVID-19

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to an unprecedented global healthcare crisis. While SARS-CoV-2-associated COVID-19 affects primarily the respiratory system, patients with COVID-19 frequently develop extrapulmonary manifestations. Notably, changes in the hematological system, including lymphocytopenia, neutrophilia and significant abnormalities of hemostatic markers, were observed early in the pandemic. Hematological manifestations have since been recognized as important parameters in the pathophysiology of SARS-CoV-2 and in the management of patients with COVID-19. In this narrative review, we summarize the state-of-the-art regarding the hematological and hemostatic abnormalities observed in patients with SARS-CoV-2-associated COVID-19, as well as the current understanding of the hematological system in the pathophysiology of acute and chronic SARS-CoV-2-associated COVID-19.

COVID-19-associated venous thromboembolism: risk of recurrence and major bleeding

Background

Complications under anticoagulant treatment in patients with COVID-19-associated venous thromboembolism (VTE) have not been consistently reported.

Objectives

This study aimed to compare the 90-day rates of VTE recurrences and major bleeding in patients with COVID-19-associated VTE versus those with VTE without COVID-19.

Methods

We used the RIETE registry to compare the 3-month outcomes in patients with COVID-19-associated VTE versus those with VTE without COVID-19.

Results

The study included 1,747 patients with COVID-19-associated VTE and 8,711 with VTE without COVID-19. Patients with COVID-19-associated VTE were more likely to be hospitalized at baseline and to present with pulmonary embolism. During the first 90 days, 123 patients (1.17%) developed VTE recurrences, and 266 (2.54%) experienced major bleeding. Patients with COVID-19-associated VTE had a similar rate of VTE recurrences (0.9% vs 1.2%) but a higher rate of major bleeding (4.6% vs 2.1%; P < .001) than those without COVID-19. Multivariable analysis adjusted for competing risks showed that patients with COVID-19-associated VTE had an increased risk of major bleeding (subhazard ratio, 1.395; 95% confidence interval, 1.037-1.877). The 30-day mortality after major bleeding was 26.3% in patients with COVID-19-associated VTE and 17.7% in those without COVID-19.

Conclusion

Patients with COVID-19-associated VTE had a 5-fold higher rate of major bleeding than VTE recurrences during the first 90 days of anticoagulation. In VTE patients without COVID-19, both rates were similar. These findings highlight the importance of carefully monitoring and optimizing anticoagulation in these patients.

Thrombotic complications in children with Coronavirus disease 2019 and Multisystem Inflammatory Syndrome of Childhood

Coronavirus disease 2019 (COVID-19) associated coagulopathy is multifactorial and involves inflammation driven hypercoagulability, endothelial dysfunction, platelet activation, and impaired fibrinolysis. Hospitalized adults with COVID-19 are at an increased risk of both venous thromboembolism and ischemic stroke, resulting in adverse outcomes, including increased mortality. Although COVID-19 in children follows a less severe course, both arterial and venous thromboses have been reported in hospitalized children with COVID-19. Additionally, some children develop a postinfectious, hyperinflammatory illness termed multisystem inflammatory syndrome of childhood (MIS-C), which is also associated with hypercoagulability and thrombosis. Several randomized trials have evaluated the safety and efficacy of antithrombotic therapy in adults with COVID-19, although similar pediatric data are lacking. In this narrative review, we discuss the postulated pathophysiology of COVID-19 coagulopathy and summarize principal findings of the recently completed adult trials of antithrombotic therapy. We provide an up-to-date summary of pediatric studies investigating the rate of venous thromboembolism and ischemic stroke in COVID-19 and multisystem inflammatory syndrome of childhood in addition to reviewing the findings of the single, nonrandomized pediatric trial investigating the safety of prophylactic anticoagulation. Lastly, we outline adult and pediatric consensus guidelines on the use of antithrombotic therapy in this cohort. A detailed discussion of the practical implementation and current limitations of published data will hopefully address the knowledge deficits surrounding the use of antithrombotic therapy in children with COVID-19 and generate hypotheses for future research.

The Prevalence of Gastrointestinal Bleeding in COVID-19 Patients: A Systematic Review and Meta-Analysis

Introduction: Severe acute respiratory syndrome coronavirus 2 caused the coronavirus disease of 2019 (COVID-19), which rapidly became a pandemic, claiming millions of lives. Apart from the main manifestations of this infection concerning the respiratory tract, such as pneumonia, there are also many manifestations from the gastrointestinal tract. Of these, bleeding from the gastrointestinal tract is a significant complication quite dangerous for life. This bleeding is divided into upper and lower, and the primary pathophysiological mechanism is the entering of the virus into the host cells through the Angiotensin-converting enzyme 2 receptors. Also, other comorbidities and the medication of corticosteroids and anticoagulants are considered to favor the occurrence of gastrointestinal bleeding (GIB). Methods: This systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, and the studies were searched in two different databases (Scopus and PubMed) from November 2019 until February 2023. All studies that reported GIB events among COVID-19 patients were included. Results: 33 studies were selected and reviewed to estimate the prevalence of GIB. A total of 134,905 patients with COVID-19 were included in these studies, and there were 1458 episodes of GIB. The prevalence of GIB, in these 33 studies, ranges from 0.47% to 19%. This range of prevalence is justified by the characteristics of the COVID-19 patients. These characteristics are the severity of COVID-19, anticoagulant and other drug treatments, the selection of only patients with gastrointestinal manifestations, etc. The pooled prevalence of gastrointestinal bleeding was estimated to be 3.05%, rising to 6.2% when only anticoagulant patients were included. Conclusions: GIB in COVID-19 patients is not a rare finding, and its appropriate and immediate treatment is necessary as it can be life-threatening. The most common clinical findings are melena and hematemesis, which characterize upper GIB. Treatment can be conservative; however, endoscopic management of bleeding with embolization is deemed necessary in some cases.

The Prevalence of Gastrointestinal Bleeding in COVID-19 Patients: A Systematic Review and Meta-Analysis

Introduction: Severe acute respiratory syndrome coronavirus 2 caused the coronavirus disease of 2019 (COVID-19), which rapidly became a pandemic, claiming millions of lives. Apart from the main manifestations of this infection concerning the respiratory tract, such as pneumonia, there are also many manifestations from the gastrointestinal tract. Of these, bleeding from the gastrointestinal tract is a significant complication quite dangerous for life. This bleeding is divided into upper and lower, and the primary pathophysiological mechanism is the entering of the virus into the host cells through the Angiotensin-converting enzyme 2 receptors. Also, other comorbidities and the medication of corticosteroids and anticoagulants are considered to favor the occurrence of gastrointestinal bleeding (GIB). Methods: This systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, and the studies were searched in two different databases (Scopus and PubMed) from November 2019 until February 2023. All studies that reported GIB events among COVID-19 patients were included. Results: 33 studies were selected and reviewed to estimate the prevalence of GIB. A total of 134,905 patients with COVID-19 were included in these studies, and there were 1458 episodes of GIB. The prevalence of GIB, in these 33 studies, ranges from 0.47% to 19%. This range of prevalence is justified by the characteristics of the COVID-19 patients. These characteristics are the severity of COVID-19, anticoagulant and other drug treatments, the selection of only patients with gastrointestinal manifestations, etc. The pooled prevalence of gastrointestinal bleeding was estimated to be 3.05%, rising to 6.2% when only anticoagulant patients were included. Conclusions: GIB in COVID-19 patients is not a rare finding, and its appropriate and immediate treatment is necessary as it can be life-threatening. The most common clinical findings are melena and hematemesis, which characterize upper GIB. Treatment can be conservative; however, endoscopic management of bleeding with embolization is deemed necessary in some cases.

A systematic review on post-discharge venous thromboembolism prophylaxis in patients with COVID-19

BACKGROUND

Coronavirus disease of 2019 (COVID-19) is associated with venous thromboembolism (VTE), not only during hospitalization but also after discharge, raising concerns about anticoagulant (AC) use for post-discharge COVID-19 patients. We aimed to systematically review the current literature on the possible benefits or risks regarding extended thromboprophylaxis.

MAIN BODY

We searched related databases from December 1, 2019, to October 6, 2022, including studies on the necessity, duration, and selection of the ideal AC regarding extended thromboprophylaxis for post-discharge COVID-19 patients. The screening of the selected databases led to 18 studies and 19 reviews and guidelines. Studies included 52,927 hospitalized COVID-19 patients, with 19.25% receiving extended thromboprophylaxis. VTE events ranging from 0 to 8.19% (median of 0.7%) occurred in a median follow-up of 49.5 days. All included studies and guidelines, except four studies, recommended post-discharge prophylaxis after an individual risk assessment indicating high thrombotic and low bleeding risk. Studies used risk assessment models (RAMs), clinical evaluation, and laboratory data to identify COVID-19 patients with a high risk of VTE. IMPROVE-DD was the most recommended RAM. Direct oral anticoagulants (DOACs) and low molecular weight heparins (LMWHs) were the most used AC classes.

CONCLUSIONS

Post-discharge prophylaxis for COVID-19 patients is recommended after an individual assessment. The IMPROVE-DD model can help predict VTE risk. After distinguishing patients who need post-discharge AC therapy, DOACs for 30-35 days and LMWHs for 40-45 days can be the drug of choice. Further studies, particularly the results of the ongoing randomized controlled trials (RCTs), are required. Also, to properly handle such patients, every physician should consider lifestyle modification in addition to pharmacological treatment for post-discharge VTE prophylaxis.

Therapeutic-dose anticoagulation or thromboprophylaxis with low-molecular-weight heparin for moderate Covid-19: meta-analysis of randomized controlled trials

BACKGROUND

We carried out a meta-analysis since there is not enough evidence to recommend for or against therapeutic-dose anticoagulation compared with thromboprophylaxis in noncritically ill patients hospitalized with Covid-19.

METHODS

We performed a systematic literature search using PubMed, Embase, Cochrane Library, and MedRxiv for randomized trials that included therapeutic-dose with low-molecular-weight heparin (LMW) or thromboprophylaxis with LMW heparin in noncritically ill patients admitted to the hospital with Covid-19. We identified five open-label studies for analysis with a total of 3220 patients. Two independent researchers selected, assessed, and extracted the data in duplicate. The outcomes evaluated were all-cause mortality, progression to invasive mechanical ventilation, incidence of venous thromboembolism, and major bleeding. The studies did not show risk for selection, detection, attrition, or reporting bias.

RESULTS

Therapeutic-dose anticoagulation with LMW heparin compared with thromboprophylaxis with LMW heparin had no significant effect of all-cause death (risk ratio [RR] 0.85; 95% confidence interval [CI] 0.67-1.07; P = 0.16; I2 = 48%), or progression to invasive mechanical ventilation (RR 0.89; CI 0.73-1.08; P = 0.24; I2: 0%). Therapeutic-dose anticoagulation significantly reduced the risk of venous thromboembolic disease (RR 0.42; 95% CI 0.28-0.62; P = 0.0001; I2 = 0%) [Number needed to treat = 37]. Major bleeding occurred in 1.79% of the patients receiving therapeutic-dose anticoagulation and in 0.97% of those receiving thromboprophylaxis [Number needed to harm 125].

CONCLUSION

Therapeutic-dose anticoagulation in noncritically ill patients with Covid-19 could be indicated for patients at high risk of venous thromboembolic disease and low risk of bleeding.

COVID-19-associated Coagulopathy Characterization using Rotational Thromboelastometry in a Prospective, Observational Cohort Study: The HemoCoV Study

INTRODUCTION

COVID-19-associated coagulopathy includes systemic and endothelial inflammation with coagulation dysregulation related to immunothrombosis. The aim of this study was to characterize this complication of SARS-CoV-2 infection in patients with moderate to severe COVID-19.

METHODS

An open-label, prospective observational study conducted in patients with COVID-19 moderate to severe acute respiratory failure admitted to an intensive care unit (ICU). Coagulation testing, including thromboelastometry, biochemical analysis and clinical variables, were collected at prespecified time points during the 30 days of ICU stay.

RESULTS

The study included 145 patients, 73.8% male, with a median age of 68 years (interquartile range - IQR 55 - 74). The most prevalent comorbidities were arterial hypertension (63.4%), obesity (44.1%) and diabetes (22.1%). Simplified acute physiology score II (SAPS II) was on average 43.5 (11 - 105) and sequential organ failure assessment (SOFA) at admission was 7.5 (0 - 14). During ICU stay, 66.9% of patients underwent invasive mechanical ventilation and 18.4% extracorporeal membrane oxygenation support; thrombotic and hemorrhagic events occurred in 22.1% and 15.1% of the patients respectively; anticoagulation with heparin was present in 99.2% of patients since early ICU stay. Death occurred in 35% of patients. Longitudinal studies revealed changes in almost all coagulation tests during the ICU stay. SOFA score, lymphocyte counts, some biochemical, inflammatory and coagulation parameters, including hypercoagulability and hypofibrinolysis seen in thromboelastometry, differed significantly (p < 0.05), between ICU admission and discharge. Hypercoagulability and hypofibrinolysis persisted throughout ICU hospitalization, showing higher incidence and severity in non-survivors.

CONCLUSION

COVID-19-associated coagulopathy is characterized by hypercoagulability and hypofibrinolysis from ICU admission, and persisted throughout the clinical course in severe COVID-19. These changes were more pronounced in patients with higher disease burden and in non-survivors.

Role of Therapeutic Anticoagulation in COVID-19: The Current Situation

Thrombotic complications from COVID-19 are now well known and contribute to significant morbidity and mortality. Different variants confer varying risks of thrombotic complications. Heparin has anti-inflammatory and antiviral effects. Due to its non-anticoagulant effects, escalated-dose anticoagulation, especially therapeutic-dose heparin, has been studied for thromboprophylaxis in hospitalized patients with COVID-19. Few randomized, controlled trials have examined the role of therapeutic anticoagulation in moderately to severely ill patients with COVID-19. Most of these patients had elevated D-dimers and low bleeding risks. Some trials used an innovative adaptive multiplatform with Bayesian analysis to answer this critical question promptly. All the trials were open-label and had several limitations. Most trials showed improvements in the meaningful clinical outcomes of organ-support-free days and reductions in thrombotic events, mainly in non-critically-ill COVID-19 patients. However, the mortality benefit needed to be more consistent. A recent meta-analysis confirmed the results. Multiple centers initially adopted intermediate-dose thromboprophylaxis, but the studies failed to show meaningful benefits. Given the new evidence, significant societies have suggested therapeutic anticoagulation in carefully selected patients who are moderately ill and do not require an intensive-care-unit level of care. There are multiple ongoing trials globally to further our understanding of therapeutic-dose thromboprophylaxis in hospitalized patients with COVID-19. In this review, we aim to summarize the current evidence regarding the use of anticoagulation in patients with COVID-19 infection.

A Case Report of Disseminated Thromboses and Cardiac Ischemia in a Patient With COVID-19 Pneumonia

The novel coronavirus disease (COVID-19) pandemic caused by the SARS-CoV-2 virus started in December 2019 in the city of Wuhan, in China's Hubei province. This virus quickly spread worldwide, and on March 11, 2020, it was declared a pandemic. Thrombosis, as a hallmark of severe disease, was recognized early as a cause of death; however, the exact pathophysiological mechanism is still not fully understood. We are reporting the case of a 46-year-old patient who presented with multiple arterial thromboses in the setting of an acute COVID-19 infection requiring systemic thrombolytic therapy and thrombectomy.

Thromboprophylaxis for Coagulopathy Related to COVID-19 in Pediatrics: A Narrative Review

In addition to harming the respiratory system, COVID-19 can affect multiple organs. Children may develop a specific complication of COVID-19 called multisystem inflammatory syndrome in children (MIS-C) which could influence the vascular system of children and cause multiple coagulopathies in the body. Information on the use of thromboprophylaxis in this condition was collected via the review of various articles. In general, different factors in immune system responses can trigger the initiation of thrombotic events. Studies have shown that starting anticoagulant prophylaxis, which contributes to decreased thrombotic events, is dependent on the patient's condition and D-dimer levels. However, further studies on pediatric populations are needed to establish the role of anticoagulants in children with this condition.

Effect of Thromboprophylaxis on Clinical Outcomes After COVID-19 Hospitalization

BACKGROUND

Patients hospitalized with COVID-19 have an increased incidence of thromboembolism. The role of extended thromboprophylaxis after hospital discharge is unclear.

OBJECTIVE

To determine whether anticoagulation is superior to placebo in reducing death and thromboembolic complications among patients discharged after COVID-19 hospitalization.

DESIGN

Prospective, randomized, double-blind, placebo-controlled clinical trial. (ClinicalTrials.gov: NCT04650087).

SETTING

Done during 2021 to 2022 among 127 U.S. hospitals.

PARTICIPANTS

Adults aged 18 years or older hospitalized with COVID-19 for 48 hours or more and ready for discharge, excluding those with a requirement for, or contraindication to, anticoagulation.

INTERVENTION

2.5 mg of apixaban versus placebo twice daily for 30 days.

MEASUREMENTS

The primary efficacy end point was a 30-day composite of death, arterial thromboembolism, and venous thromboembolism. The primary safety end points were 30-day major bleeding and clinically relevant nonmajor bleeding.

RESULTS

Enrollment was terminated early, after 1217 participants were randomly assigned, because of a lower than anticipated event rate and a declining rate of COVID-19 hospitalizations. Median age was 54 years, 50.4% were women, 26.5% were Black, and 16.7% were Hispanic; 30.7% had a World Health Organization severity score of 5 or greater, and 11.0% had an International Medical Prevention Registry on Venous Thromboembolism risk prediction score of greater than 4. Incidence of the primary end point was 2.13% (95% CI, 1.14 to 3.62) in the apixaban group and 2.31% (CI, 1.27 to 3.84) in the placebo group. Major bleeding occurred in 2 (0.4%) and 1 (0.2%) and clinically relevant nonmajor bleeding occurred in 3 (0.6%) and 6 (1.1%) apixaban-treated and placebo-treated participants, respectively. By day 30, thirty-six (3.0%) participants were lost to follow-up, and 8.5% of apixaban and 11.9% of placebo participants permanently discontinued the study drug treatment.

LIMITATIONS

The introduction of SARS-CoV-2 vaccines decreased the risk for hospitalization and death. Study enrollment spanned the peaks of the Delta and Omicron variants in the United States, which influenced illness severity.

CONCLUSION

The incidence of death or thromboembolism was low in this cohort of patients discharged after hospitalization with COVID-19. Because of early enrollment termination, the results were imprecise and the study was inconclusive.

PRIMARY FUNDING SOURCE

National Institutes of Health.

Therapeutic considerations for prevention and treatment of thrombotic events in COVID-19

Thrombosis is a known complication of SARS-CoV-2 infection, particularly within a severely symptomatic subset of patients with COVID-19 disease, in whom an aggressive host immune response leads to cytokine storm syndrome (CSS). The incidence of thrombotic events coinciding with CSS may contribute to the severe morbidity and mortality observed in association with COVID-19. This review provides an overview of pharmacologic approaches based upon an emerging understanding of the mechanisms responsible for thrombosis across a spectrum of COVID-19 disease involving an interplay between immunologic and pro-thrombotic events, including endothelial injury, platelet activation, altered coagulation pathways, and impaired fibrinolysis.

The intersection of obesity and (long) COVID-19: Hypoxia, thrombotic inflammation, and vascular endothelial injury

The role of hypoxia, vascular endothelial injury, and thrombotic inflammation in worsening COVID-19 symptoms has been generally recognized. Damaged vascular endothelium plays a crucial role in forming in situ thrombosis, pulmonary dysfunction, and hypoxemia. Thrombotic inflammation can further aggravate local vascular endothelial injury and affect ventilation and blood flow ratio. According to the results of many studies, obesity is an independent risk factor for a variety of severe respiratory diseases and contributes to high mechanical ventilation rate, high mortality, and slow recovery in COVID-19 patients. This review will explore the mechanisms by which obesity may aggravate the acute phase of COVID-19 and delay long COVID recovery by affecting hypoxia, vascular endothelial injury, and thrombotic inflammation. A systematic search of PubMed database was conducted for papers published since January 2020, using the medical subject headings of "COVID-19" and "long COVID" combined with the following keywords: "obesity," "thrombosis," "endothelial injury," "inflammation," "hypoxia," "treatment," and "anticoagulation." In patients with obesity, the accumulation of central fat restricts the expansion of alveoli, exacerbating the pulmonary dysfunction caused by SARS-CoV-2 invasion, inflammatory damage, and lung edema. Abnormal fat secretion and immune impairment further aggravate the original tissue damage and inflammation diffusion. Obesity weakens baseline vascular endothelium function leading to an early injury and pre-thrombotic state after infection. Enhanced procoagulant activity and microthrombi promote early obstruction of the vascular. Obesity also prolongs the duration of symptoms and increases the risk of sequelae after hospital discharge. Persistent viral presence, long-term inflammation, microclots, and hypoxia may contribute to the development of persistent symptoms, suggesting that patients with obesity are uniquely susceptible to long COVID. Early interventions, including supplemental oxygen, comprehensive antithrombotic therapy, and anti-inflammatory drugs, show effectiveness in many studies in the prevention of serious hypoxia, thromboembolic events, and systemic inflammation, and are therefore recommended to reduce intensive care unit admission, mortality, and sequelae.

To prophylax or not, and how much and how long? Controversies in VTE prevention for medical inpatients, including COVID-19 inpatients

The field of thromboprophylaxis for acutely ill medical patients, including those hospitalized for COVID-19, is rapidly evolving both in the inpatient setting and the immediate post-hospital discharge period. Recent data reveal the importance of incorporating holistic thromboembolic outcomes that encompass both venous thromboembolism (VTE) and arterial thromboembolism, as thromboprophylaxis with low-dose direct oral anticoagulants has been shown to reduce major and fatal vascular events, especially against a background of dual pathway inhibition with aspirin. In addition, recent post hoc analyses from randomized trial data have established 5 key bleeding-risk factors that, if removed, reveal a low-bleeding- risk medically ill population and, conversely, key individual risk factors, such as advanced age, a past history of cancer or VTE, an elevated D-dimer, or the use of a validated VTE risk score-the IMPROVE VTE score using established cutoffs-to predict a high-VTE-risk medically ill population that benefits from extended postdischarge thromboprophylaxis. Last, thromboprophylaxis of a high-thrombotic-risk subset of medically ill patients, those with COVID-19, is rapidly evolving, both during hospitalization and post discharge. This article reviews 3 controversial topics in the thromboprophylaxis of hospitalized acutely ill medical patients: (1) clinical relevance of key efficacy and safety outcomes incorporated into randomized trials but not incorporated into relevant antithrombotic guidelines on the topic, (2) the use of individual risk factors or risk models of low-bleeding-risk and high-thrombotic-risk subgroups of medically ill inpatients that benefit from extended thromboprophylaxis, and (3) thromboprophylaxis of hospitalized COVID-19 patients, including extended postdischarge thromboprophylaxis.

Higher Dose Anticoagulation Cannot Prevent Disease Progression in COVID-19 Patients: A Systematic Review and Meta-Analysis

Implementation of higher dose (HD) thromboprophylaxis has been considered in patients infected with coronavirus disease 2019 (COVID-19). Our aim was to compare HD to standard dose (SD) thromboprophylaxis in COVID-19 patients. The protocol is registered on PROSPERO (CRD42021284808). We searched for randomised controlled studies (CENTRAL, Embase, Medline and medRxviv) that compared HD to SD anticoagulation in COVID-19 and analysed outcomes such as mortality, thrombotic events, bleedings, and disease progression. The statistical analyses were made using the random effects model. Fourteen articles were included (6253 patients). HD compared with SD showed no difference in mortality (OR 0.83 [95% CI 0.54−1.28]). The use of HD was associated with a decreased risk of thrombosis (OR 0.58 [95% CI 0.44−0.76]), although with an increased risk of major bleeding (OR 1.64 [95% CI 1.25−2.16]). The cohort with D-dimer < 1 mg/mL showed no effect (OR 1.19 [95% CI 0.67−2.11]), but in the case of D-dimer > 1 mg/mL, a tendency of lower risk in the HD group was observed (OR 0.56 [95% CI 0.31−1.00]). The need for intubation in moderately ill patients showed a nonsignificant lower likelihood in the HD group (OR 0.82 [95% CI 0.63−1.08]). We cannot advocate for HD in all COVID-19 patients, although it shows some nonsignificant benefits on disease progression in those with elevated D-dimer who do not need ICU admission.

Need for a Standardized Translational Drug Development Platform: Lessons Learned from the Repurposing of Drugs for COVID-19

In the absence of drugs to treat or prevent COVID-19, drug repurposing can be a valuable strategy. Despite a substantial number of clinical trials, drug repurposing did not deliver on its promise. While success was observed with some repurposed drugs (e.g., remdesivir, dexamethasone, tocilizumab, baricitinib), others failed to show clinical efficacy. One reason is the lack of clear translational processes based on adequate preclinical profiling before clinical evaluation. Combined with limitations of existing in vitro and in vivo models, there is a need for a systematic approach to urgent antiviral drug development in the context of a global pandemic. We implemented a methodology to test repurposed and experimental drugs to generate robust preclinical evidence for further clinical development. This translational drug development platform comprises in vitro, ex vivo, and in vivo models of SARS-CoV-2, along with pharmacokinetic modeling and simulation approaches to evaluate exposure levels in plasma and target organs. Here, we provide examples of identified repurposed antiviral drugs tested within our multidisciplinary collaboration to highlight lessons learned in urgent antiviral drug development during the COVID-19 pandemic. Our data confirm the importance of assessing in vitro and in vivo potency in multiple assays to boost the translatability of pre-clinical data. The value of pharmacokinetic modeling and simulations for compound prioritization is also discussed. We advocate the need for a standardized translational drug development platform for mild-to-moderate COVID-19 to generate preclinical evidence in support of clinical trials. We propose clear prerequisites for progression of drug candidates for repurposing into clinical trials. Further research is needed to gain a deeper understanding of the scope and limitations of the presented translational drug development platform.

D-dimer: old dogmas, new (COVID-19) tricks

D-dimer is a fibrin degradation product encompassing multiple cross-linked D domains and/or E domains present in the original fibrinogen molecule, whose generation is only theoretically possible when hemostasis and fibrinolysis pathways are concomitantly activated. D-dimer measurement has now become a pillar in the diagnosis/exclusion and prognostication of venous thromboembolism (VTE) and disseminated intravascular coagulation (DIC), when incorporated into validated clinical algorithms and especially using age-adjusted diagnostic thresholds. Although emerging evidence is also supporting its use for predicting the duration of anticoagulant therapy in certain categories of patients, the spectrum of clinical applications is constantly expanding beyond traditional thrombotic pathologies to the diagnosis of acute aortic dissection, acute intestinal ischemia and cerebral venous thrombosis among others, embracing also clinical management of coronavirus disease 2019 (COVID-19). Recent findings attest that D-dimer elevations are commonplace in patients with severe acute respiratory syndrome (SARS-CoV-2) infection (especially in those with thrombosis), its value predicts the clinical severity (up to death) of COVID-19 and remains more frequently increased in COVID-19 patients with post-discharge clinical sequelae. Further, D-dimer-based anticoagulant escalation may be associated with a lower risk of death in patients with severe SARS-CoV-2 infection and, finally, D-dimer elevation post-COVID-19 vaccination mirrors an increased risk of developing vaccine-induced thrombocytopenia and thrombosis (VITT).