Rescue therapy for severe COVID-19-associated acute respiratory distress syndrome with tissue plasminogen activator: A case series

Pathophysiological mechanisms of thrombosis in acute and long COVID-19

COVID-19 patients have a high incidence of thrombosis, and thromboembolic complications are associated with severe COVID-19 and high mortality. COVID-19 disease is associated with a hyper-inflammatory response (cytokine storm) mediated by the immune system. However, the role of the inflammatory response in thrombosis remains incompletely understood. In this review, we investigate the crosstalk between inflammation and thrombosis in the context of COVID-19, focusing on the contributions of inflammation to the pathogenesis of thrombosis, and propose combined use of anti-inflammatory and anticoagulant therapeutics. Under inflammatory conditions, the interactions between neutrophils and platelets, platelet activation, monocyte tissue factor expression, microparticle release, and phosphatidylserine (PS) externalization as well as complement activation are collectively involved in immune-thrombosis. Inflammation results in the activation and apoptosis of blood cells, leading to microparticle release and PS externalization on blood cells and microparticles, which significantly enhances the catalytic efficiency of the tenase and prothrombinase complexes, and promotes thrombin-mediated fibrin generation and local blood clot formation. Given the risk of thrombosis in the COVID-19, the importance of antithrombotic therapies has been generally recognized, but certain deficiencies and treatment gaps in remain. Antiplatelet drugs are not in combination with anticoagulant treatments, thus fail to dampen platelet procoagulant activity. Current treatments also do not propose an optimal time for anticoagulation. The efficacy of anticoagulant treatments depends on the time of therapy initiation. The best time for antithrombotic therapy is as early as possible after diagnosis, ideally in the early stage of the disease. We also elaborate on the possible mechanisms of long COVID thromboembolic complications, including persistent inflammation, endothelial injury and dysfunction, and coagulation abnormalities. The above-mentioned contents provide therapeutic strategies for COVID-19 patients and further improve patient outcomes.

Systemic thrombolytics as rescue therapy for COVID-19 patients with acute respiratory distress syndrome: A retrospective observational study

Background

Coronavirus disease 2019 (COVID-19) pneumonia with severe acute respiratory distress syndrome (ARDS) is often associated with a progressive respiratory failure that is refractory to maximal ventilatory support and other ARDS strategies. Studies show evidence of a hypercoagulable state in COVID-19 patients, including capillary thrombosis and alveolar fibrin deposits which impede normal gas exchange. In this context, thrombolysis is considered as a salvage therapy to rescue critically hypoxemic patients.

Methods

In this retrospective observational study, the efficacy of thrombolysis on outcome of COVID-19 ARDS with respiratory failure was analyzed. Patients with severe ARDS and d-dimer levels of 5 μg/ml or above were initiated on alteplase, as a 25 mg bolus followed by a 25 mg infusion over 22 h. Primary outcome was intensive care unit (ICU) mortality and secondary outcomes were change in PaO2/FiO2 24 h after thrombolysis, avoidance of intubation, ventilator free days (VFD), and ICU and hospital length-of-stay (LOS).

Results

Thirteen out of 34 patients with severe COVID ARDS underwent thrombolysis. They had lower ICU mortality than non-thrombolysed patients (23.1% vs. 71.4%, P = 0.006), greater percentage improvement in PaO2/FiO2 (116% vs. 31.5%, P = 0.002), more VFDs (13 days vs. 0 day, P = 0.004), and lesser requirement for intubation (23.1% vs. 76.2%, P = 0.004). ICU and hospital LOS were similar.

Conclusion

Thrombolysis can be considered as a rescue therapy for nonintubated COVID-19 ARDS patients with severe hypoxemic respiratory failure, who show evidence of a procoagulant state. Larger studies are needed before inclusion into the regular treatment protocol for COVID-19 patients.

Case series of nebulizing r‐tPA for COVID ‐19 induced acute respiratory distress syndrome

Fibrin deposition in the alveolar spaces during pulmonary involvement of COVID‐19 impairs the O₂/CO₂ exchange and leads to respiratory symptoms. In this report, Recombinant Tissue Plasminogen Activator (r‐tPA) has been nebulized to 3 critically ill COVID‐19 patients in order to resolve the deposited fibrin while avoiding the risk of bleeding. Based on these observations, nebulization of r‐tPA may be a potential therapeutic approach and new area of research for future studies.

Coronavirus Disease 2019-Associated Coagulopathy

Coronavirus disease 2019 (COVID-19)-associated coagulopathy is an acute illness characterized by thrombosis with or without hemorrhage after COVID-19 infection. Clinical symptoms of COVID-19-associated coagulopathy can occur at any anatomical site. Various forms of venous thromboembolism, including deep vein thrombosis and pulmonary embolism, are common in acutely ill patients with COVID-19. Laboratory findings, such as D-dimer and platelet counts, can help diagnose COVID-19-associated coagulopathy. Anticoagulation using direct oral anticoagulants and low-molecular-weight heparin is essential for the treatment of COVID-19-associated coagulopathy. Prophylactic anticoagulants are important in preventing COVID-19-associated coagulopathy in patients with severe COVID-19. In particular, the early initiation of prophylactic anticoagulation in patients with COVID-19 can improve survival rates without the risk of serious bleeding events.

Pharmacotherapy consideration of thrombolytic medications in COVID-19-associated ARDS

BACKGROUND

In late 2019, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) which is responsible for coronavirus disease (COVID-19), was identified as the new pathogen to lead pneumonia in Wuhan, China, which has spread all over the world and developed into a pandemic. Despite the over 1 year of pandemic, due to the lack of an effective treatment plan, the morbidity and mortality of COVID-19 remains high. Efforts are underway to find the optimal management for this viral disease.

MAIN BODY

SARS-CoV-2 could simultaneously affect multiple organs with variable degrees of severity, from mild to critical disease. Overproduction of pro-inflammatory mediators, exacerbated cellular and humoral immune responses, and coagulopathy such as Pulmonary Intravascular Coagulopathy (PIC) contributes to cell injuries. Considering the pathophysiology of the disease and multiple microthrombi developments in COVID-19, thrombolytic medications seem to play a role in the management of the disease. Beyond the anticoagulation, the exact role of thrombolytic medications in the management of patients with COVID-19-associated acute respiratory distress syndrome (ARDS) is not explicit. This review focuses on current progress in underlying mechanisms of COVID-19-associated pulmonary intravascular coagulopathy, the historical use of thrombolytic drugs in the management of ARDS, and pharmacotherapy considerations of thrombolytic therapy, their possible benefits, and pitfalls in COVID-19-associated ARDS.

CONCLUSIONS

Inhaled or intravenous administration of thrombolytics appears to be a salvage therapy for severe ARDS associated with COVID-19 by prompt attenuation of lung injury. Considering the pathogenesis of COVID-19-related ARDS and mechanism of action of thrombolytic agents, thrombolytics appear attractive options in stable patients without contraindications.

Suppression of fibrin(ogen)-driven pathologies in disease models through controlled knockdown by lipid nanoparticle delivery of siRNA

Fibrinogen plays a pathologic role in multiple diseases. It contributes to thrombosis and modifies inflammatory and immune responses, supported by studies in mice expressing fibrinogen variants with altered function or with a germline fibrinogen deficiency. However, therapeutic strategies to safely and effectively tailor plasma fibrinogen concentration are lacking. Here, we developed a strategy to tune fibrinogen expression by administering lipid nanoparticle (LNP)-encapsulated small interfering RNA (siRNA) targeting the fibrinogen α chain (siFga). Three distinct LNP-siFga reagents reduced both hepatic Fga messenger RNA and fibrinogen levels in platelets and plasma, with plasma levels decreased to 42%, 16%, and 4% of normal within 1 week of administration. Using the most potent siFga, circulating fibrinogen was controllably decreased to 32%, 14%, and 5% of baseline with 0.5, 1.0, and 2.0 mg/kg doses, respectively. Whole blood from mice treated with siFga formed clots with significantly decreased clot strength ex vivo, but siFga treatment did not compromise hemostasis following saphenous vein puncture or tail transection. In an endotoxemia model, siFga suppressed the acute phase response and decreased plasma fibrinogen, D-dimer, and proinflammatory cytokine levels. In a sterile peritonitis model, siFga restored normal macrophage migration in plasminogen-deficient mice. Finally, treatment of mice with siFga decreased the metastatic potential of tumor cells in a manner comparable to that observed in fibrinogen-deficient mice. The results indicate that siFga causes robust and controllable depletion of fibrinogen and provides the proof-of-concept that this strategy can modulate the pleiotropic effects of fibrinogen in relevant disease models.

MUlticenter STudy of tissue plasminogen activator (alteplase) use in COVID-19 severe respiratory failure (MUST COVID): A retrospective cohort study

Background

Few therapies exist to treat severe COVID-19 respiratory failure once it develops. Given known diffuse pulmonary microthrombi on autopsy studies of COVID-19 patients, we hypothesized that tissue plasminogen activator (tPA) may improve pulmonary function in COVID-19 respiratory failure.

Methods

A multicenter, retrospective, observational study of patients with confirmed COVID-19 and severe respiratory failure who received systemic tPA (alteplase) was performed. Seventy-nine adults from seven medical centers were included in the final analysis after institutional review boards' approval; 23 were excluded from analysis because tPA was administered for pulmonary macroembolism or deep venous thrombosis. The primary outcome was improvement in the PaO2/FiO2 ratio from baseline to 48 h after tPA. Linear mixed modeling was used for analysis.

Results

tPA was associated with significant PaO2/FiO2 improvement at 48 h (estimated paired difference = 23.1 ± 6.7), which was sustained at 72 h (interaction term p < 0.00). tPA administration was also associated with improved National Early Warning Score 2 scores at 24, 48, and 72 h after receiving tPA (interaction term p = 0.00). D-dimer was significantly elevated immediately after tPA, consistent with lysis of formed clot. Patients with declining respiratory status preceding tPA administration had more marked improvement in PaO2/FiO2 ratios than those who had poor but stable (not declining) respiratory status. There was one intracranial hemorrhage, which occurred within 24 h following tPA administration.

Conclusions

These data suggest tPA is associated with significant improvement in pulmonary function in severe COVID-19 respiratory failure, especially in patients whose pulmonary function is in decline, and has an acceptable safety profile in this patient population.

COVID-19 and venous thromboembolism: A narrative review

COVID-19 (severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2]) is associated with coagulopathy through numerous mechanisms. The reported incidence of venous thromboembolism (VTE) in hospitalized patients with COVID-19 has varied widely, and several meta-analyses have been performed to assess the overall prevalence of VTE. The novelty of this coronavirus strain along with its unique mechanisms for microvascular and macrovascular thrombosis has led to uncertainty as to how to diagnose, prevent, and treat thrombosis in patients affected by this virus. This review discusses the epidemiology and pathophysiology of thrombosis in the setting of SARS-CoV-2 infection along with an updated review on the preventative and treatment strategies for VTE associated with SARS-CoV-2 infection.

Nuts and bolts of COVID-19 associated coagulopathy: the essentials for management and treatment

INTRODUCTION

COVID-19-associated coagulopathy (CAC) is a well-recognized hematologic complication among patients with severe COVID-19 disease, where macro- and micro-thrombosis can lead to multiorgan injury and failure. Major societal guidelines that have published on the management of CAC are based on consensus of expert opinion, with the current evidence available. As a result of limited studies, there are many clinical scenarios that are yet to be addressed, with expert opinion varying on a number of important clinical issues regarding CAC management.

METHODS

In this review, we utilize current societal guidelines to provide a framework for practitioners in managing their patients with CAC. We have also provided three clinical scenarios that implement important principles of anticoagulation in patients with COVID-19.

CONCLUSION

Overall, decisions should be made on acase by cases basis and based on the providers understanding of each patient's medical history, clinical course and perceived risk.

Clinical Management of COVID-19: A Review of Pharmacological Treatment Options

Since the outbreak and subsequent declaration of COVID-19 as a global pandemic in March 2020, concerted efforts have been applied by the scientific community to curtail the spread of the disease and find a cure. While vaccines constitute a vital part of the public health strategy to reduce the burden of COVID-19, the management of this disease will continue to rely heavily on pharmacotherapy. This study aims to provide an updated review of pharmacological agents that have been developed and/or repurposed for the treatment of COVID-19. To this end, a comprehensive literature search was conducted using the PubMed, Google Scholar, and LitCovid databases. Relevant clinical studies on drugs used in the management of COVID-19 were identified and evaluated in terms of evidence of efficacy and safety. To date, the FDA has approved three therapies for the treatment of COVID-19 Emergency Use Authorization: convalescent plasma, remdesivir, and casirivimab/imdevimab (REGN-COV2). Drugs such as lopinavir/ritonavir, umifenovir, favipiravir, anakinra, chloroquine, hydroxychloroquine, tocilizumab, interferons, tissue plasminogen activator, intravenous immunoglobulins, and nafamosat have been used off-label with mixed therapeutic results. Adjunctive administration of corticosteroids is also very common. The clinical experience with these approved and repurposed drugs is limited, and data on efficacy for the new indication are not strong. Overall, the response of the global scientific community to the COVID-19 pandemic has been impressive, as evident from the volume of scientific literature elucidating the molecular biology and pathophysiology of SARS-CoV-2 and the approval of three new drugs for clinical management. Reviewed studies have shown mixed data on efficacy and safety of the currently utilized drugs. The lack of standard treatment for COVID-19 has made it difficult to interpret results from most of the published studies due to the risk of attribution error. The long-term effects of drugs can only be assessed after several years of clinical experience; therefore, the efficacy and safety of current COVID-19 therapeutics should continue to be rigorously monitored as part of post-marketing studies.

Associations of D-Dimer on Admission and Clinical Features of COVID-19 Patients: A Systematic Review, Meta-Analysis, and Meta-Regression

Background

Dynamic D-dimer level is a key biomarker for the severity and mortality of COVID-19 (coronavirus disease 2019). How aberrant fibrinolysis influences the clinical progression of COVID-19 presents a clinicopathological dilemma challenging intensivists.

Methods

We performed meta-analysis and meta regression to analyze the associations of plasma D-dimer with 106 clinical variables to identify a panoramic view of the derangements of fibrinolysis in 14,862 patients of 42 studies. There were no limitations of age, gender, race, and country. Raw data of each group were extracted separately by two investigators. Individual data of case series, median and interquartile range, and ranges of median or mean were converted to SDM (standard deviation of mean).

Findings

The weighted mean difference of D-dimer was 0.97 µg/mL (95% CI 0.65, 1.29) between mild and severe groups, as shown by meta-analysis. Publication bias was significant. Meta-regression identified 58 of 106 clinical variables were associated with plasma D-dimer levels. Of these, 11 readouts were negatively related to the level of plasma D-dimer. Further, age and gender were confounding factors. There were 22 variables independently correlated with the D-dimer level, including respiratory rate, dyspnea plasma K+, glucose, SpO2, BUN (blood urea nitrogen), bilirubin, ALT (alanine aminotransferase), AST (aspartate aminotransferase), systolic blood pressure, and CK (creatine kinase).

Interpretation

These findings support elevated D-dimer as an independent predictor for both mortality and complications. The identified D-dimer-associated clinical variables draw a landscape integrating the aggregate effects of systemically suppressive and pulmonary hyperactive derangements of fibrinolysis, and the D-dimer-associated clinical biomarkers, and conceptually parameters could be combined for risk stratification, potentially for tracking thrombolytic therapy or alternative interventions.

Fibrinolysis Shutdown in COVID-19: Clinical Manifestations, Molecular Mechanisms, and Therapeutic Implications

The COVID-19 pandemic has introduced a global public health threat unparalleled in our history. The most severe cases are marked by ARDS attributed to microvascular thrombosis. Hypercoagulability, resulting in a profoundly prothrombotic state, is a distinct feature of COVID-19 and is accentuated by a high incidence of fibrinolysis shutdown. The aims of this review were to describe the manifestations of fibrinolysis shutdown in COVID-19 and its associated outcomes, review the molecular mechanisms of dysregulated fibrinolysis associated with COVID-19, and discuss potential implications and therapeutic targets for patients with severe COVID-19.

Acute Respiratory Distress Syndrome

Acute Respiratory Distress Syndrome (ARDS) is defined as the rapid onset of non-cardiogenic pulmonary edema resulting in respiratory failure and hypoxemia. Efforts over the past 25 years, such as those of the ARDS and Prevention and Early Treatment of Acute Lung Injury (PETAL) Networks, have demonstrated a praiseworthy collaboration to further optimize the management of ARDS. However, improvements have been only moderate and ARDS remains a leading cause of mortality in the perioperative and critical care setting. Recently, the significant morbidity and mortality of ARDS have been emphasized by its high incidence in Coronavirus Disease 2019 (COVID-19) patients. A major hurdle to reducing ARDS mortality is that current treatment is limited to preventive measures – such as the use of lung-protective ventilation. Therapeutic approaches targeting the underlying inflammatory lung disease are areas of intensive research, but have not been clinically implemented. Nevertheless, basic science and clinical research efforts that are aimed at identifying novel treatment approaches and further improving outcomes for ARDS are ongoing. Here, we review evidence-based management approaches for ARDS, while highlighting those being investigated or heavily utilized in ARDS associated with COVID-19.

Acute Respiratory Distress Syndrome remains a condition that carries a high mortality. Evidence-based clinical management and emerging concepts for new therapies for COVID-19 are reviewed.

Fibrinolysis influences SARS-CoV-2 infection in ciliated cells

Rapid spread of COVID-19 has caused an unprecedented pandemic worldwide, and an inserted furin site in SARS-CoV-2 spike protein (S) may account for increased transmissibility. Plasmin, and other host proteases, may cleave the furin site of SARS-CoV-2 S protein and γ subunits of epithelial sodium channels (γ ENaC), resulting in an increment in virus infectivity and channel activity. As for the importance of ENaC in the regulation of airway surface and alveolar fluid homeostasis, whether SARS-CoV-2 will share and strengthen the cleavage network with ENaC proteins at the single-cell level is urgently worthy of consideration. To address this issue, we analyzed single-cell RNA sequence (scRNA-seq) datasets, and found the PLAU (encoding urokinase plasminogen activator), SCNN1G (γENaC), and ACE2 (SARS-CoV-2 receptor) were co-expressed in alveolar epithelial, basal, club, and ciliated epithelial cells. The relative expression level of PLAU, TMPRSS2, and ACE2 were significantly upregulated in severe COVID-19 patients and SARS-CoV-2 infected cell lines using Seurat and DESeq2 R packages. Moreover, the increments in PLAU, FURIN, TMPRSS2, and ACE2 were predominately observed in different epithelial cells and leukocytes. Accordingly, SARS-CoV-2 may share and strengthen the ENaC fibrinolytic proteases network in ACE2 positive airway and alveolar epithelial cells, which may expedite virus infusion into the susceptible cells and bring about ENaC associated edematous respiratory condition.

Endothelial pulsatile shear stress is a backstop for COVID-19

There has not been any means to inhibit replication of the SARS-CoV-2 virus responsible for the rapid, deadly spread of the COVID-19 pandemic and an effective, safe, tested across diverse populations vaccine still requires extensive investigation. This review deals with the repurpose of a wellness technology initially fabricated for combating physical inactivity by increasing muscular activity. Its action increases pulsatile shear stress (PSS) to the endothelium such that the bioavailability of nitric oxide (NO) and other mediators are increased throughout the body. In vitro evidence indicates that NO inhibits SARS-CoV-2 virus replication but there are no publications of NO delivery to the virus in vivo. It will be shown that increased PSS has potential in vivo to exert anti-viral properties of NO as well as to benefit endothelial manifestations of COVID-19 thereby serving as a safe and effective backstop.

Cancer patients and COVID-19: Mortality, serious complications, biomarkers, and ways forward

The SARS-CoV-2 (COVID-19) pandemic has particularly serious consequences for cancer patients, as they are at high risk for severe complications and mortality due to the virus since cancer patients are immunocompromised. Preliminary evidence suggests that patients with hematological, and metastatic malignancies are particularly susceptible to developing severe COVID-19 illness, which leads to poor prognosis. Biomarkers including C-reactive protein and interleukin-6 may be predictors of outcome and, therefore, crucial in assessing COVID-19 illness severity in cancer patients. A patient-specific risk and benefit inventory should be completed, and expert guidelines consulted when deciding to continue or postpone therapeutic interventions. This review presents preliminary evidence of COVID-19 infection and its impact on cancer, as well as discussion of general guidelines for the treatment and management of cancer patients with COVID-19.

Impaired fibrinolysis in critically ill COVID-19 patients

Background

Critically ill coronavirus disease 2019 (COVID-19) patients present with a hypercoagulable state with high rates of macrovascular and microvascular thrombosis, for which hypofibrinolysis might be an important contributing factor.

Methods

We retrospectively analysed 20 critically ill COVID-19 patients at Innsbruck Medical University Hospital whose coagulation function was tested with ClotPro® and compared with that of 60 healthy individuals at Augsburg University Clinic. ClotPro is a viscoelastic whole blood coagulation testing device. It includes the TPA test, which uses tissue factor (TF)-activated whole blood with added recombinant tissue-derived plasminogen activator (r-tPA) to induce fibrinolysis. For this purpose, the lysis time (LT) is measured as the time from when maximum clot firmness (MCF) is reached until MCF falls by 50%. We compared COVID-19 patients with prolonged LT in the TPA test and those with normal LT.

Results

Critically ill COVID-19 patients showed hypercoagulability in ClotPro assays. MCF was higher in the EX test (TF-activated assay), IN test (ellagic acid-activated assay), and FIB test (functional fibrinogen assay) with decreased maximum lysis (ML) in the EX test (hypofibrinolysis) and highly prolonged TPA test LT (decreased fibrinolytic response), as compared with healthy persons. COVID-19 patients with decreased fibrinolytic response showed higher fibrinogen levels, higher thrombocyte count, higher C-reactive protein levels, and decreased ML in the EX test and IN test.

Conclusion

Critically ill COVID-19 patients have impaired fibrinolysis. This hypofibrinolytic state could be at least partially dependent on a decreased fibrinolytic response.

COVID-19-Related Cardiovascular Disease and Practical Considerations for Perioperative Clinicians

Coronavirus disease 2019 (COVID-19) has a clinical course predominated by acute respiratory failure due to viral pneumonia with possible acute respiratory distress syndrome. However, nearly one third of infected patients, especially those with preexisting cardiovascular (CV) disease, are reported to present with some combination of acute cardiac injury, myocarditis, heart failure, cardiogenic shock, or significant dysrhythmias. In addition, COVID-19 infections are also associated with high rates of thromboembolic and disseminated intravascular coagulation complications. Severe myocarditis and heart failure have both been reported as the initial presenting conditions in COVID-19 infection. This review highlights the important considerations related to the CV manifestations of COVID-19 infections, describes the mechanisms and clinical presentation of CV injury, and provides practical management and therapy suggestions. This narrative review is based primarily on the multiple case series and cohorts from the largest initial COVID-19 outbreak centers (ie, Wuhan, China, and Italy); hence, nearly all presented data and findings are retrospective in nature with the attendant limitations of such reports.

Guidance for the Management of Patients with Vascular Disease or Cardiovascular Risk Factors and COVID-19: Position Paper from VAS-European Independent Foundation in Angiology/Vascular Medicine

COVID-19 is also manifested with hypercoagulability, pulmonary intravascular coagulation, microangiopathy, and venous thromboembolism (VTE) or arterial thrombosis. Predisposing risk factors to severe COVID-19 are male sex, underlying cardiovascular disease, or cardiovascular risk factors including noncontrolled diabetes mellitus or arterial hypertension, obesity, and advanced age. The VAS-European Independent Foundation in Angiology/Vascular Medicine draws attention to patients with vascular disease (VD) and presents an integral strategy for the management of patients with VD or cardiovascular risk factors (VD-CVR) and COVID-19. VAS recommends (1) a COVID-19-oriented primary health care network for patients with VD-CVR for identification of patients with VD-CVR in the community and patients' education for disease symptoms, use of eHealth technology, adherence to the antithrombotic and vascular regulating treatments, and (2) close medical follow-up for efficacious control of VD progression and prompt application of physical and social distancing measures in case of new epidemic waves. For patients with VD-CVR who receive home treatment for COVID-19, VAS recommends assessment for (1) disease worsening risk and prioritized hospitalization of those at high risk and (2) VTE risk assessment and thromboprophylaxis with rivaroxaban, betrixaban, or low-molecular-weight heparin (LMWH) for those at high risk. For hospitalized patients with VD-CVR and COVID-19, VAS recommends (1) routine thromboprophylaxis with weight-adjusted intermediate doses of LMWH (unless contraindication); (2) LMWH as the drug of choice over unfractionated heparin or direct oral anticoagulants for the treatment of VTE or hypercoagulability; (3) careful evaluation of the risk for disease worsening and prompt application of targeted antiviral or convalescence treatments; (4) monitoring of D-dimer for optimization of the antithrombotic treatment; and (5) evaluation of the risk of VTE before hospital discharge using the IMPROVE-D-dimer score and prolonged post-discharge thromboprophylaxis with rivaroxaban, betrixaban, or LMWH.

Observational study of the use of recombinant tissue-type plasminogen activator in COVID-19 shows a decrease in physiological dead space

In December 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged as the causative agent for coronavirus disease 2019 (COVID-19), a clinical syndrome with high incidence of acute respiratory distress syndrome (ARDS). Part of the pathophysiology of COVID-19-induced ARDS is explained by increased dead space ventilation from pulmonary microthrombi; this is supported by the existence of alveolar capillary microthrombi found on autopsies [1, 2]. This has prompted the use of therapeutic anticoagulation and thrombolytics [3–5]. Thus far, no clinical trials have been completed to evaluate the use of recombinant tissue-type plasminogen activator (rt-PA) to treat COVID-19. The objective of this study was to determine whether rt-PA administration decreases dead space ventilation in patients with COVID-19.

#COVID19-induced ARDS is partly explained by the presence of microthrombi, motivating the use of thrombolytics. This study shows that thrombolytics decrease dead space ventilation in COVID-19 ARDS patients.https://bit.ly/2GdM44a

Insufficient hyperfibrinolysis in COVID-19: a systematic review of thrombolysis based on meta-analysis and meta-regression

Background How aberrant fibrinolysis influences the clinical progression of COVID-19 presents a clinicopathological dilemma challenging intensivists. To investigate whether abnormal fibrinolysis is a culprit or protector or both, we associated elevated plasma D-dimer with clinical variables to identify a panoramic view of the derangements of fibrinolysis that contribute to the pathogenesis of COVID-19 based on studies available in the literature. Methods We performed this systematic review based on both meta-analysis and meta-regression to compute the correlation of D-dimer at admission with clinical features of COVID-19 patients in retrospective studies or case series. We searched the databases until Aug 18, 2020, with no limitations by language. The first hits were screened, data extracted, and analyzed in duplicate. We did the random-effects meta-analyses and meta-regressions (both univariate and multivariate). D-dimer associated clinical variables and potential mechanisms were schematically reasoned and graphed. Findings Our search identified 42 observational, or retrospective, or case series from six countries (n=14,862 patients) with all races and ages from 1 to 98-year-old. The weighted mean difference of D-dimer was 0.97 μg/mL (95% CI 0.65, 1.29) between relatively mild (or healthy control) and severely affected groups with significant publication bias. Univariate meta-regression identified 58 of 106 clinical variables were associated with plasma D-dimer levels, including 3 demographics, 5 comorbidies, 22 laboratory tests, 18 organ injury biomarkers, 8 severe complications, and 2 outcomes (discharge and death). Of these, 11 readouts were negatively associated with the level of plasma D-dimer. Further, age and gender were confounding factors for the identified D-dimer associated variables. There were 22 variables independently correlated with the D-dimer level, including respiratory rate, dyspnea plasma K+, glucose, SpO2, BUN, bilirubin, ALT, AST, systolic blood pressure, and CK. We thus propose that "insufficient hyperfibrinolysis (fibrinolysis is accelerated but unable to prevent adverse clinical impact for clinical deterioration COVID-19)" as a peculiar mechanism. Interpretation The findings of this meta-analysis- and meta-regression-based systematic review supports elevated D-dimer as an independent predictor for mortality and severe complications. D-dimer-associated clinical variables draw a landscape integrating the aggregate effects of systemically suppressive and locally (i.e., in the lung) hyperactive derangements of fibrinolysis. D-dimer and associated clinical biomarkers and conceptually parameters could be combined for risk stratification, potentially for tracking thrombolytic therapy or alternative interventions.

Coagulopathy in COVID-19: Focus on vascular thrombotic events

SARS-CoV-2 causes a phenotype of pneumonia with diverse manifestation, which is termed as coronavirus disease 2019 (COVID-19). An impressive high transmission rate allows COVID-19 conferring enormous challenge for clinicians worldwide, and developing to a pandemic level. Combined with a series of complications, a part of COVID-19 patients progress into severe cases, which critically contributes to the risk of fatality. To date, coagulopathy has been found as a prominent feature of COVID-19 and severe coagulation dysfunction may be associated with poor prognosis. Coagulopathy in COVID-19 may predispose patients to hypercoagulability-related disorders including thrombosis and even fatal vascular events. Inflammatory storm, uncontrolled inflammation-mediated endothelial injury and renin angiotensin system (RAS) dysregulation are the potential mechanisms. Ongoing efforts made to develop promising therapies provide several potential strategies for hypercoagulability in COVID-19. In this review, we introduce the clinical features of coagulation and the increased vascular thrombotic risk conferred by coagulopathy according to present reports about COVID-19. The potential underlying mechanisms and emerging therapeutic avenues are discussed, emphasizing an urgent need for effective interventions.