Perspective on fibrinolytic therapy in COVID-19: the potential of inhalation therapy against suppressed-fibrinolytic-type DIC

Nebulized alteplase in coronavirus disease 2019 pneumonia: a case series

BACKGROUND

Many patients with severe coronavirus disease 2019 pneumonia exhibit signs of microthrombosis. Previous studies discussed intravenous fibrinolytic agents as potential add-on therapy in these patients. Therefore, we propose the inhalative administration of fibrinolytics as a possible safer alternative.

CASE PRESENTATION

This case series describes five white male patients, aged 51-78 years, treated with off-label inhalation of alteplase between November and December 2020. All patients suffered from severe severe acute respiratory syndrome coronavirus 2 infection with respiratory failure. Pulmonary embolism was ruled out by pulmonary angiogram in computed tomography scans, and all patients showed signs of coronavirus disease 2019 pneumonia. Four patients improved clinically, while one patient with advanced chronic diseases died due to multiple organ failure. No directly associated adverse effects were observed following inhalation of alteplase.

CONCLUSION

This case series warrants further attention to investigate inhalative alteplase as an additional treatment in patients with severe coronavirus disease 2019 infection.

Optimizing Dual Antiplatelet Therapy in the Perioperative Period for Spine Surgery After Recent Percutaneous Coronary Intervention: A Comprehensive Review, Synthesis, and Catalyst for Protocol Formulation

The increased incidence of spine surgery within the past decade has highlighted the importance of robust perioperative management to improve patient outcomes overall. Coronary artery disease is a common medical comorbidity present in the population of individuals who receive surgery for spinal pathology that is often treated with dual antiplatelet therapy (DAPT) after percutaneous coronary intervention. Discontinuation of DAPT before surgical intervention is typically indicated; however, contradictory evidence exists in the literature regarding the timing of DAPT use and discontinuation in the perioperative period. We review the most recent cardiac and spine literature on the intricacies of percutaneous coronary intervention and its associated risks in the postoperative period. We further propose protocols for DAPT use after both elective and urgent spine surgery to optimize perioperative care.

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.

The Mutual Relationship among Cardiovascular Diseases and COVID-19: Focus on Micronutrients Imbalance

Micronutrients are ions and vitamins humbly required by the human body. They play a main role in several physiological mechanisms and their imbalance is strongly associated with potentially-fatal complications. Micronutrient imbalance is associated with many cardiovascular diseases, such as arrythmias, heart failure, and ischemic heart disease. It has been also observed in coronavirus disease 2019 (COVID-19), particularly in most severe patients. The relationship between cardiovascular diseases and COVID-19 is mutual: the latter triggers cardiovascular disease onset and worsening while patients with previous cardiovascular disease may develop a more severe form of COVID-19. In addition to the well-known pathophysiological mechanisms binding COVID-19 and cardiovascular diseases together, increasing importance is being given to the impact of micronutrient alterations, often present during COVID-19 and able to affect the balance responsible for a good functioning of the cardiovascular system. In particular, hypokalemia, hypomagnesemia, hyponatremia, and hypocalcemia are strongly associated with worse outcome, while vitamin A and D deficiency are associated with thromboembolic events in COVID-19. Thus, considering how frequent the cardiovascular involvement is in patients with COVID-19, and how it majorly affects their prognosis, this manuscript provides a comprehensive review on the role of micronutrient imbalance in the interconnection between COVID-19 and cardiovascular diseases.

Therapeutic anticoagulation using heparin in early phase severe coronavirus disease 2019: A retrospective study

Background

Although several reports recommend the use of systemic anticoagulation therapy in patients with severe coronavirus disease 2019 (COVID-19) pneumonia, appropriate target population and timing of administration are unknown. We assessed association between therapeutic anticoagulation administration with unfractionated heparin and outcomes in patients with severe COVID-19 pneumonia, assuming that anticoagulant administration effects are influenced by therapy timing.

Methods

This retrospective observational study included severe COVID-19 patients requiring mechanical ventilation in a tertiary emergency critical care hospital intensive care unit (ICU) in Japan from May 1, 2020 to September 30, 2021. All included patients were divided into early and late-phase administration groups based on therapeutic anticoagulant administration timing (≤5 and >5 days, respectively, after commencing oxygen therapy). Primary outcomes (in-hospital mortality and adverse events related to anticoagulation therapy) and secondary outcomes [veno-venous extracorporeal membrane oxygenation (ECMO), ventilator-free days (VFD), and ICU-free days] were compared between groups using univariate and multivariate models.

Results

Of 198 included patients 104 (52.5%) and 94 (47.5%) were in early-phase and late-phase administration groups, respectively. Although background characteristics were similar between the groups, the early-phase administration group had a significantly lower in-hospital mortality rate (3.8% vs. 27.7%; p < 0.001), lower adverse event rates (1.9% vs. 12.8%; p < 0.001), significantly longer VFD and ICU-free days, and lower ECMO rates, than the late-phase administration group, in the multivariate model.

Conclusions

Late administration of therapeutic-dose anticoagulation in patients with severe COVID-19 pneumonia was significantly associated with worse outcomes than early administration.

COVID-19 associated coagulopathy: Mechanisms and host-directed treatment

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) is associated with specific coagulopathy that frequently occurs during the different phases of coronavirus disease 2019 (COVID-19) and can result in thrombotic complications and/or death. This COVID-19-associated coagulopathy (CAC) exhibits some of the features associated with thrombotic microangiopathy, particularly complement-mediated hemolytic-uremic syndrome. In some cases, due to the anti-phospholipid antibodies, CAC resembles catastrophic anti-phospholipid syndrome. In other patients, it exhibits features of hemophagocytic syndrome. CAC is mainly identified by: increases in fibrinogen, D-dimers, and von Willebrand factor (released from activated endothelial cells), consumption of a disintegrin and metalloproteinase with thrombospondin type 1 motifs, member 13 (ADAMTS13), over activated and dysregulated complement, and elevated plasma cytokine levels. CAC manifests as both major cardiovascular and/or cerebrovascular events and dysfunctional microcirculation, which leads to multiple organ damage. It is not clear whether the mainstay of COVID-19 is complement overactivation, cytokine/chemokine activation, or a combination of these activities. Available data have suggested that non-critically ill hospitalized patients should be administered full-dose heparin. In critically ill, full dose heparin treatment is discouraged due to higher mortality rate. In addition to anti-coagulation, four different host-directed therapeutic pathways have recently emerged that influence CAC: (1) Anti-von Willebrand factor monoclonal antibodies; (2) activated complement C5a inhibitors; (3) recombinant ADAMTS13; and (4) Interleukin (IL)-1 and IL-6 antibodies. Moreover, neutralizing monoclonal antibodies against the virus surface protein have been tested. However, the role of antiplatelet treatment remains unclear for patients with COVID-19.

Coagulopathy and Fibrinolytic Pathophysiology in COVID-19 and SARS-CoV-2 Vaccination

Coronavirus Disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and is frequently complicated by thrombosis. In some cases of severe COVID-19, fibrinolysis may be markedly enhanced within a few days, resulting in fatal bleeding. In the treatment of COVID-19, attention should be paid to both coagulation activation and fibrinolytic activation. Various thromboses are known to occur after vaccination with SARS-CoV-2 vaccines. Vaccine-induced immune thrombotic thrombocytopenia (VITT) can occur after adenovirus-vectored vaccination, and is characterized by the detection of anti-platelet factor 4 antibodies by enzyme-linked immunosorbent assay and thrombosis in unusual locations such as cerebral venous sinuses and visceral veins. Treatment comprises high-dose immunoglobulin, argatroban, and fondaparinux. Some VITT cases show marked decreases in fibrinogen and platelets and marked increases in D-dimer, suggesting the presence of enhanced-fibrinolytic-type disseminated intravascular coagulation with a high risk of bleeding. In the treatment of VITT, evaluation of both coagulation activation and fibrinolytic activation is important, adjusting treatments accordingly to improve outcomes.

Therapeutic Strategies for Disseminated Intravascular Coagulation Associated with Aortic Aneurysm

Aortic aneurysms are sometimes associated with enhanced-fibrinolytic-type disseminated intravascular coagulation (DIC). In enhanced-fibrinolytic-type DIC, both coagulation and fibrinolysis are markedly activated. Typical cases show decreased platelet counts and fibrinogen levels, increased concentrations of fibrin/fibrinogen degradation products (FDP) and D-dimer, and increased FDP/D-dimer ratios. Thrombin-antithrombin complex or prothrombin fragment 1 + 2, as markers of coagulation activation, and plasmin-α₂ plasmin inhibitor complex, a marker of fibrinolytic activation, are all markedly increased. Prolongation of prothrombin time (PT) is not so obvious, and the activated partial thromboplastin time (APTT) is rather shortened in some cases. As a result, DIC can be neither diagnosed nor excluded based on PT and APTT alone. Many of the factors involved in coagulation and fibrinolysis activation are serine proteases. Treatment of enhanced-fibrinolytic-type DIC requires consideration of how to control the function of these serine proteases. The cornerstone of DIC treatment is treatment of the underlying pathology. However, in some cases surgery is either not possible or exacerbates the DIC associated with aortic aneurysm. In such cases, pharmacotherapy becomes even more important. Unfractionated heparin, other heparins, synthetic protease inhibitors, recombinant thrombomodulin, and direct oral anticoagulants (DOACs) are agents that inhibit serine proteases, and all are effective against DIC. Inhibition of activated coagulation factors by anticoagulants is key to the treatment of DIC. Among them, DOACs can be taken orally and is useful for outpatient treatment. Combination therapy of heparin and nafamostat allows fine-adjustment of anticoagulant and antifibrinolytic effects. While warfarin is an anticoagulant, this agent is ineffective in the treatment of DIC because it inhibits the production of coagulation factors as substrates without inhibiting activated coagulation factors. In addition, monotherapy using tranexamic acid in cases of enhanced-fibrinolytic-type DIC may induce fatal thrombosis. If tranexamic acid is needed for DIC, combination with anticoagulant therapy is of critical importance.

Lung epithelial and endothelial damage, loss of tissue repair, inhibition of fibrinolysis, and cellular senescence in fatal COVID-19

Coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is characterized by respiratory distress, multiorgan dysfunction, and, in some cases, death. The pathological mechanisms underlying COVID-19 respiratory distress and the interplay with aggravating risk factors have not been fully defined. Lung autopsy samples from 18 patients with fatal COVID-19, with symptom onset-to-death times ranging from 3 to 47 days, and antemortem plasma samples from 6 of these cases were evaluated using deep sequencing of SARS-CoV-2 RNA, multiplex plasma protein measurements, and pulmonary gene expression and imaging analyses. Prominent histopathological features in this case series included progressive diffuse alveolar damage with excessive thrombosis and late-onset pulmonary tissue and vascular remodeling. Acute damage at the alveolar-capillary barrier was characterized by the loss of surfactant protein expression with injury to alveolar epithelial cells, endothelial cells, respiratory epithelial basal cells, and defective tissue repair processes. Other key findings included impaired clot fibrinolysis with increased concentrations of plasma and lung plasminogen activator inhibitor-1 and modulation of cellular senescence markers, including p21 and sirtuin-1, in both lung epithelial and endothelial cells. Together, these findings further define the molecular pathological features underlying the pulmonary response to SARS-CoV-2 infection and provide important insights into signaling pathways that may be amenable to therapeutic intervention.

Abnormal Coagulation Function of Patients With COVID-19 Is Significantly Related to Hypocalcemia and Severe Inflammation

This study aimed to detect, analyze, and correlate the clinical characteristics, blood coagulation functions, blood calcium levels, and inflammatory factors in patients with mild and severe COVID-19 infections. The enrolled COVID-19 infected patients were from Wuhan Jin Yin-tan Hospital (17 cases, Wuhan, China), Suzhou Infectious Disease Hospital (87 cases, Suzhou, China), and Xuzhou Infectious Disease Hospital (14 cases, Xuzhou, China). After admission, basic information was collected; X-ray and chest CT images were obtained; and data from routine blood tests, liver and kidney function, myocardial enzymes, electrolytes, blood coagulation function, (erythrocyte sedimentation rate) ESR, C-reactive protein (CRP), IL-6, procalcitonin (PCT), calcitonin, and other laboratory tests were obtained. The patients were grouped according to the clinical classification method based on the pneumonia diagnosis and treatment plan for new coronavirus infection (trial version 7) in China. The measurements from mild (56 cases) and severe cases (51 cases) were compared and analyzed. Most COVID-19 patients presented with fever. Chest X-ray and CT images showed multiple patchy and ground glass opacities in the lungs of COVID 19 infected patients, especially in patients with severe cases. Compared with patients with mild infection, patients with severe infection were older (p = 0.023) and had a significant increase in AST and BUN. The levels of CK, LDH, CK-MB, proBNP, and Myo in patients with severe COVID-19 infection were also increased significantly compared to those in patients with mild cases. Patients with severe COVID-19 infections presented coagulation dysfunction and increased D-dimer and fibrin degradation product (FDP) levels. Severe COVID-19 patients had low serum calcium ion (Ca²⁺) concentrations and high calcitonin and PCT levels and exhibited serious systemic inflammation. Ca²⁺ in COVID-19 patients was significantly negatively correlated with PCT, calcitonin, D-dimer, PFDP, ESR, CRP and IL-6. D-dimer in COVID-19 patients was a significantly positively correlated with CRP and IL-6. In conclusion, patients with severe COVID-19 infection presented significant metabolic dysfunction and abnormal blood coagulation, a sharp increase in inflammatory factors and calcitonin and procalcitonin levels, and a significant decrease in Ca²⁺. Decreased Ca²⁺ and coagulation dysfunction in COVID-19 patients were significantly correlated with each other and with inflammatory factors.

An evaluation of venous thromboembolism by whole-body enhanced CT scan for critical COVID-19 pneumonia with markedly rises of coagulopathy related factors: a case series study

Background

Coronavirus disease (COVID-19) pneumonitis associated with severe respiratory failure has a high mortality rate. Based on recent reports, the most severely ill patients present with coagulopathy, and disseminated intravascular coagulation (DIC)-like massive intravascular clot formation is frequently observed. Coagulopathy has emerged as a significant contributor to thrombotic complications. Although recommendations have been made for anticoagulant use for COVID-19, no guidelines have been specified.

Case summary

We describe four cases of critical COVID-19 with thrombosis detected by enhanced CT scan. The CT findings of all cases demonstrated typical findings of COVID-19 and pulmonary embolism or deep venous thrombus without critical exacerbation. Two patients died of respiratory failure due to COVID-19.

Discussion

Previous reports have suggested coagulopathy with thrombotic signs as the main pathological feature of COVID-19, but no previous reports have focused on coagulopathy evaluated by whole-body enhanced CT scan. Changes in hemostatic biomarkers, represented by an increase in D-dimer and fibrin/fibrinogen degradation products, indicated that the essence of coagulopathy was massive fibrin formation. Although there were no clinical symptoms related to their prognosis, critical COVID-19-induced systemic thrombus formation was observed.

Conclusions

Therapeutic dose anticoagulants should be considered for critical COVID-19 because of induced coagulopathy, and aggressive follow-up by whole body enhanced CT scan for systemic venous thromboembolism (VTE) is necessary.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12959-021-00280-z.

The role of rotational thromboelastometry during the COVID-19 pandemic: a narrative review

The coronavirus disease 2019 (COVID-19) pandemic is currently recognized as a global health crisis. This viral infection is frequently associated with hypercoagulability, with a high incidence of thromboembolic complications that can be fatal. In many situations, the standard coagulation tests (SCT) fail to detect this state of hypercoagulability in patients with COVID-19 since clotting times are either not or only mildly affected. The role of viscoelastic tests such as rotational thromboelastometry (ROTEM®) during this pandemic is explored in this review. COVID-19-associated coagulopathy, as measured using the rotational thromboelastometry parameters, can vary from hypercoagulability due to increased fibrin polymerization and decreased fibrinolysis to bleeding from hypocoagulability. The use of a multimodal diagnostic and monitoring approach, including both rotational thromboelastometry and SCT, such as plasma fibrinogen and D-dimer concentrations, is recommended. Rotational thromboelastometry provides comprehensive information about the full coagulation status of each patient and detects individual variations. Since COVID-19-associated coagulopathy is a very dynamic process, the phenotype can change during the course of infection and in response to anticoagulation therapy. Data from published literature provide evidence that the combination of rotational thromboelastometry and SCT analysis is helpful in detecting hemostasis issues, guiding anticoagulant therapy, and improving outcomes in COVID-19 patients. However, more research is needed to develop evidence-based guidelines and protocols.

Characterization of fibrin/fibrinogen degradation products reagents and their utility in critical care patients with enhanced fibrinolysis

INTRODUCTION

Fibrin/fibrinogen degradation products (FDP) values reflect coagulation and fibrinolysis status, and FDP levels are helpful for diagnosis and classification of disseminated intravascular coagulation (DIC). FDP measurement has always played a key role in diagnosing DIC, a phenomenon that has recently gained renewed attention because of its occurrence in coronavirus disease 2019 (COVID-19) patients. Although the evaluation of FDP is crucial for the management of critical care, the variability among FDP reagents is unclear. In this study, we aimed to compare LIASAUTO P-FDP with three FDP reagents and investigate their characteristics.

METHODS

In total, 172 plasmas samples were used in the correlation. The sample data were divided into three groups including negative, no and positive discrepancy based on the discrepancy percentages calculated from each correlation between LIASAUTO P-FDP and other three reagents. D-dimer, plasmin-α₂ plasmin inhibitor complex (PIC), fibrin monomer complex (FMC), fibrinogen (Fbg) and Plasmin-α₂ Plasmin Inhibitor (α₂ PI) were measured and included in data analysis.

RESULTS

The positive discrepancy groups showed higher D-dimer, PIC and FMC values than the negative discrepancy groups. The data indicated that LIASAUTO P-FDP had higher reactivity to D-dimer than other reagents and the values were elevated in the fibrinolysis-enhanced samples with various FDP fragments.

CONCLUSION

LIASAUTO P-FDP displayed the reactivity towards various fibrin/fibrinogen degradation products, and it might be useful for DIC diagnosis because the fibrinolytic status differed in the DIC types and stages.

COVID-19-associated coagulopathy and disseminated intravascular coagulation

The pathology of coronavirus disease 2019 (COVID-19) is exacerbated by the progression of thrombosis, and disseminated intravascular coagulation (DIC), and cytokine storms. The most frequently reported coagulation/fibrinolytic abnormality in COVID-19 is the increase in d-dimer, and its relationship with prognosis has been discussed. However, limits exist to the utility of evaluation by d-dimer alone. In addition, since the coagulation/fibrinolytic condition sometimes fluctuates within a short period of time, regular examinations in recognition of the significance of the examination are desirable. The pathophysiology of disseminated intravascular coagulation (DIC) associated with COVID-19 is very different from that of septic DIC, and both thrombotic and hemorrhagic pathologies should be noted. COVID-19 thrombosis includes macro- and microthrombosis, with diagnosis of the latter depending on markers of coagulation and fibrinolysis. Treatment of COVID-19 is classified into antiviral treatment, cytokine storm treatment, and thrombosis treatment. Rather than providing uniform treatment, the treatment method most suitable for the severity and stage should be selected. Combination therapy with heparin and nafamostat is expected to develop in the future. Fibrinolytic therapy and adsorption therapy require further study