How We Interpret Thrombosis with Thrombocytopenia Syndrome?

Platelets play an important role in hemostasis, and a low platelet count usually increases the risk of bleeding. Conditions in which thrombosis occurs despite low platelet counts are referred to as thrombosis with thrombocytopenia syndrome, including heparin-induced thrombocytopenia, vaccine-induced immune thrombotic thrombocytopenia, paroxysmal nocturnal hemoglobinuria, antiphospholipid syndrome, thrombotic microangiopathy (TMA), and disseminated intravascular coagulation. TMA includes thrombotic thrombocytopenic purpura, Shiga toxin-producing Escherichia coli-associated hemolytic uremic syndrome (HUS), and atypical HUS. Patients with these pathologies present with thrombosis and consumptive thrombocytopenia associated with the activation of platelets and the coagulation system. Treatment varies from disease to disease, and many diseases have direct impacts on mortality and organ prognosis if therapeutic interventions are not promptly implemented. Underlying diseases and the results of physical examinations and general laboratory tests as part of a thorough workup for patients should promptly lead to therapeutic intervention before definitive diagnosis. For some diseases, the diagnosis and initial treatment must proceed in parallel. Utilization of not only laboratory tests but also various scoring systems is important for validating therapeutic interventions based on clinical information.

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.

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.

[Improving outcome of COVID-19-associated thrombosis: the need for evaluation of fibrinolytic activation].

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 and is known to have thrombotic complications. Various-sized thrombosis occurs in the arteries and veins, especially in lung tissue. The prevention and treatment of thrombosis is an important issue that is directly linked to its prognosis. Additionally, the drastic fibrinolytic enhancement and lethal bleeding in some severe COVID-19 are important issues. The efficacy of antiplatelet for COVID-19 is controversial. Thus, warfarin or tranexamic acid alone should be avoided. Heparin is effective for mild to moderate COVID-19 but is ineffective in severe cases since the anticoagulant activity of heparin is insufficient or heparin increases major bleeding. In severe COVID-19 cases with drastic fibrinolytic enhancement, heparin and nafamostat combination therapy may avoid lethal bleeding. In COVID-19 clinical practice, not only the coagulation activation was evaluated but also the fibrinolytic activation to consider treatment strategies.

[Acquired factor V inhibitor].

Since acquired factor V inhibitor (FV-INH) has been first reported in Germany in 1955, about 200 cases have been recorded globally. The incidence of FV-INH is extremely low, with a rate of 0.023-0.09 per million persons per year. FV-INH formation is caused by infection, use of antibiotics and other drugs, surgery, and diseases, including malignancy and autoimmune disorder. Some patients with FV-INH present with abnormal clinical laboratory test results but have no hemorrhagic symptoms. Others experience life-threatening bleeding. Moreover, thrombosis can sometimes occur. The diagnosis is based on prolonged prothrombin time (PT) and activated partial thromboplastin time (APTT), an inhibitor pattern shown by a cross-mixing test of PT and APTT, decreased factor V activity, and detection of FV-INH. Treatment includes hemostatic and immunosuppressive therapy. However, in some cases, the monitoring of progression alone is appropriate. In terms of hemostatic therapies, infusion of platelet concentrates and administration of recombinant factor VIIa are highly useful. However, no definitive treatment strategy has been established. In about 50% of cases, FV-INH is eliminated spontaneously. Therefore, immunosuppressive therapy is recommended only for hemorrhagic patients or those at high risk of hemorrhage. Prednisolone is generally used for the management of immunosuppression. However, some reports have shown that the administration of rituximab, cyclophosphamide, and intravenous immunoglobulin and plasma-exchange can be utilized as treatments.

Thrombomodulin in disseminated intravascular coagulation and other critical conditions-a multi-faceted anticoagulant protein with therapeutic potential.

Thrombomodulin plays a vital role in maintaining intravascular patency due to its anticoagulant, antiinflammatory, and cytoprotective properties. However, under pathological conditions such as sepsis and systemic inflammation, endothelial thrombomodulin expression is downregulated and its function impaired. As a result, administering thrombomodulin represents a potential therapeutic modality. Recently, the effect of recombinant thrombomodulin administration in sepsis-induced coagulopathy was evaluated in a randomized controlled study (SCARLET). A 2.6% 28-day absolute mortality reduction (26.8% vs. 29.4%) was reported in 800 patients studied that was not statistically significant; however, a post hoc analysis revealed a 5.4% absolute mortality reduction among the patients who fulfilled the entry criterion at baseline. The risk of bleeding did not increase compared to placebo control. Favorable effects of thrombomodulin administration have been reported not only in sepsis-induced coagulopathy but also in disseminated intravascular coagulations with various backgrounds. Interestingly, beneficial effects of recombinant thrombomodulin in respiratory, renal, and cardiovascular diseases might depend on its anti-inflammatory mechanisms. In this review, we summarize the accumulated knowledge of endogenous as well as recombinant thrombomodulin from basic to clinical aspects and suggest future directions for this novel therapeutic agent.

[DIC: state-of-the-art in diagnosis and management].

Disseminated intravascular coagulation (DIC) is a serious disease that, in the presence of underlying disease, causes persistent, generalized, marked coagulation activation and recurrent formation of microthrombi in microvessels. Although the DIC pathophysiology differs from that of thrombotic microangiopathy (TMA), distinguishing the two is sometimes challenging. At least, differential diagnosis using coagulation tests of values such as PT and APTT is difficult. While the mechanisms of DIC development differ according to the underlying disease, tissue factor plays a vital role in common. The classification of the DIC type is essential not only for understanding pathophysiology but also for the appropriate choice of DIC treatment. As a revision of the old DIC diagnostic criteria of the Japanese Ministry of Health, Labour and Welfare, new diagnostic criteria for DIC have been established by the Japanese Society on Thrombosis and Hemostasis (2017 edition). The new criteria are estimated to play a pivotal role in the future diagnosis of DIC. From the perspective of analysis by genetic techniques, the protein C/thrombomodulin system and plasminogen activator inhibitor play crucial roles in the control and development of DIC.

Congenital coagulation factor X deficiency: Genetic analysis of five patients and functional characterization of mutant factor X proteins.

Congenital factor X (FX) deficiency is a rare bleeding disorder that is inherited as an autosomal recessive trait. In this study, a genetic analysis of the FX gene was performed in five families with this disorder. Four heterozygous mutations [p.Gly154Arg, p.Val236Met, p.Gly263Val and p.Arg387Cys] and one pair of compound heterozygous FX gene mutations consisting of p.Gly406Ser and p.Val424Phe were identified. Mutant FX proteins containing the identified amino acid substitutions were also expressed in cultured cells. These proteins were analysed by enzyme-linked immunosorbent assay and pulse-chase experiments. The results demonstrated normal intracellular synthesis and extracellular secretion of mutant FX proteins carrying the p.Val236Met, p.Arg387Cys and p.Gly406Ser amino acid substitutions. However, the results also showed that the p.Gly154Arg, p.Gly263Val and p.Val424Phe proteins were secreted less efficiently than the wild-type protein, although they were synthesized normally in the cell. Collectively, these observations suggest that the amino acid substitutions p.Gly154Arg, p.Gly263Val and p.Val424Phe induce protein misfolding, leading to the intracellular degradation of many FX proteins containing any of these mutations, and ultimately to the development of FX deficiency. On the other hand, for the p.Val236Met, p.Arg387Cys and p.Gly406Ser mutant proteins, we hypothesize that secreted FX proteins have impaired coagulant activities due to functional defects caused by these amino acid substitutions.

[Thrombosis in myeloproliferative neoplasms].

Among all types of myeloproliferative neoplasms (MPNs), polycythemia vera (PV) and essential thrombocythemia (ET) require careful management of both thrombosis and hemostasis. One recent concern associated with MPNs is the JAK2 mutation (V617F). This mutation is essential for MPN pathology, but it has also garnered attention for its association with thrombosis. Several studies have reported the mechanisms underlying the onset of thrombosis in both PV and ET and have also discussed the association between JAK2 mutations and thrombotic tendencies. Arterial thrombosis is a common clinical symptom that is associated with the diagnosis and course of both PV and ET. Particularly, cerebral infarction has been identified as the leading cause of death in patients with untreated PV. Notably, PV and ET are also associated with a high incidence of venous thromboembolism (VTE). The occurrence of this type of thrombosis at atypical sites, such as cerebral venous sinus thrombosis and splanchnic vein thrombosis (SVT), is not uncommon. Generally, patients with PV and ET have good life expectancy; their treatment essentially focuses on dealing with thrombosis and bleeding. Phlebotomy may be used for treating patients with PV; however, low-dose aspirin is used to prevent the onset of arterial thrombosis. For patients with a history of VTE, oral anticoagulants are commonly prescribed to prevent recurrence.

The approval of revised diagnostic criteria for DIC from the Japanese Society on Thrombosis and Hemostasis.

As proposed diagnostic criteria for DIC from the Japanese Society on Thrombosis and Hemostasis has been approved and revised, the contents and changes are informed.

Proposal for new diagnostic criteria for DIC from the Japanese Society on Thrombosis and Hemostasis.

Disseminated intravascular coagulation (DIC) is a serious disease that, in the presence of underlying disease, causes persistent, generalized, marked coagulation activation. Early treatment based on an appropriate diagnosis is very important for improving patients' prognosis, to which end diagnostic criteria play a key role. Several criteria have been proposed, but each has its strengths and weaknesses, and improved criteria are needed. Widespread use of coagulofibrinolytic markers has elucidated that the pathology of DIC differs greatly as a function of the underlying disease. Thus, discriminating use of DIC diagnostic criteria that take underlying diseases into account is important. DIC diagnostic criteria that are well known in Japan include the Japanese Ministry of Health and Welfare's old DIC diagnostic criteria (JMHW criteria), the International Society on Thrombosis and Haemostasis's DIC diagnostic criteria (ISTH criteria), and the Japanese Association for Acute Medicine's acute-stage DIC diagnostic criteria (JAAM criteria). Those criteria have their respective drawbacks: the sensitivity of the ISTH criteria is poor, the JAAM criteria cannot be applied to all underlying diseases, and the JMHW criteria have poor sensitivity in the case of infections, do not use molecular markers, and result in misdiagnosis. The Japanese Society on Thrombosis and Hemostasis's newly proposed provisional draft DIC diagnostic criteria (new criteria) use diagnostic criteria classifications of "hematopoietic disorder type", "infectious type", and "basic type" based on the underlying pathology. For the hematopoietic disorder type the platelet count is omitted from the score, while for the infectious type, fibrinogen is omitted from the score. Also, points are added if the platelet count decreases with time. In the new criteria, molecular markers and antithrombin activity have been newly included, and as a countermeasure for misdiagnosis, 3 points are deducted if there is liver failure. In this paper, we discuss various problems encountered with DIC diagnosis, and we describe the new criteria together with the events that led to their creation. These new diagnostic criteria take into account the underlying diseases of wide area, and we expect that they will serve clinicians well due to the above adaptations and improvements.

Revision of the Japanese Association for Acute Medicine (JAAM) disseminated intravascular coagulation (DIC) diagnostic criteria using antithrombin activity.

BACKGROUND: With advances in the treatment of sepsis, the systemic inflammatory response syndrome (SIRS) has been losing its prognostic power. Since the SIRS category is no longer used for the diagnosis of sepsis, the disseminated intravascular coagulation (DIC) diagnostic criteria released by Japanese Association for Acute Medicine (JAAM) should be modified. Thus, the purpose of this study was to examine the appropriateness of replacing the SIRS score with antithrombin activity in JAAM-DIC diagnostic criteria. METHODS: We analyzed data from 819 septic patients who had received recombinant thrombomodulin. The relationships between the 28-day mortality rate and baseline laboratory and clinical parameters were examined using univariate and multivariate analyses, and the impact of replacing the SIRS criteria with antithrombin activity was evaluated. RESULTS: The SIRS score, prothrombin time ratio, and antithrombin activity were associated with the 28-day mortality rate (P values = 0.013, 0.018, and 0.003, respectively, by multivariate analysis). A modified version of the JAAM-DIC diagnostic criteria using an antithrombin activity <70 % was capable of diagnosing the identical number (n = 706) and a similar severity of patients (mortality, 34.6 % versus 34.8 %). CONCLUSION: Since anticoagulant therapy is expected to be more effective in patients with more severe coagulation disorders, the modified version of the JAAM-DIC diagnostic criteria might be useful for discriminating patients with sepsis who are good candidates for anticoagulant therapy.

[Classifying types of DIC: clinical features and animal models].

Disseminated intravascular coagulation (DIC) is a pathological state in which varying degrees of fibrinolytic activation are seen simultaneously as systemic, persistent, and marked coagulation activation in the presence of an underlying disease. Suppressed-fibrinolytic-type DIC usually develops in patients with sepsis. Coagulation activation is severe, while fibrinolytic activation is mild. Enhanced-fibrinolytic-type DIC usually occurs with acute promyelocytic leukemia (APL). Both coagulation activation and fibrinolytic activation are severe in affected patients. Balanced-fibrinolytic-type DIC is usually seen in patients with solid tumors, and has a pathogenesis intermediate between those of the two aforementioned types. In animal DIC models, lipopolysaccharide (LPS)-induced forms of DIC are similar to suppressed-fibrinolytic-type DIC, whereas models of tissue factor (TF)-induced DIC have features similar to those of enhanced-fibrinolytic/balanced-fibrinolytic DIC. We are moving in the direction of more appropriate selection of treatment based on DIC type.

Recombinant human soluble thrombomodulin (thrombomodulin alfa) to treat disseminated intravascular coagulation in solid tumors: results of a one-arm prospective trial.

BACKGROUND: Disseminated intravascular coagulation (DIC) associated with solid tumors (DIC-ST) is often encountered in clinical practice. Patients with DIC-ST are usually in poor condition and have bleeding diathesis due to advanced or metastatic diseases. Although some affected patients are treated with heparin, this strategy has not been prospectively studied. Recombinant human soluble thrombomodulin (thrombomodulin alfa, TM-α) is a new anticoagulant developed in Japan. We conducted a prospective study that evaluated the efficacy and safety of TM-α in patients with DIC-ST. METHODS: A prospective one-arm study with TM-α was conducted for DIC-ST. TM-α (380 U/kg) was given for 30 min intravenously once daily for 6-14 days. The primary efficacy endpoint was the DIC resolution rate. Change in DIC scores and improvement in bleeding symptoms and outcomes were also evaluated. Safety endpoints included the incidence of bleeding-related adverse events. RESULTS: A total of 101 patients were treated with TM-α. The three main underlying malignant diseases were lung, stomach, and breast cancer, which accounted for 60 % of all patients. The DIC resolution rate was 34.0 % at the end of TM-α treatment. Improvement in DIC scores was seen in 55.2 % of patients, while only 22.9 % of patients had worsening of DIC scores. The overall survival rate was 55.4 % on day 28. The incidence of hemorrhage related to TM-α was 12.9 % until day 28. Cases of severe hemorrhage related to TM-α did not occur. CONCLUSIONS: TM-α is effective and safe for DIC-ST. This agent is the treatment of choice for the management of DIC-ST.

Efficacy and bleeding risk of antithrombin supplementation in septic disseminated intravascular coagulation: a secondary survey.

INTRODUCTION: In a previous report, we demonstrated a favorable trend for supplementation with antithrombin (AT) concentrate at a dosage of 3,000 IU/day over 1,500 IU/day for the treatment of sepsis-associated disseminated intravascular coagulation (DIC) in patients with an AT activity of 70% or less. Since the survival difference did not reach statistical significance, we planned to examine the effects in a larger number of cases with severer disease. METHODS: We performed a non-randomized multi-institutional survey. In total, 307 septic DIC patients who had AT activity less than 40% and who had undergone AT substitution at a dose of either 1,500 IU/day or 3,000 IU/day for three consecutive days were analyzed. Of these, 259 patients received 1,500 IU/day (AT1500 group) and 48 patients received 3,000 IU/day (AT3000 group). The primary efficacy endpoints were recovery from DIC by day 7 and an all-cause mortality on day 28. Adverse bleeding events were also examined. A logistic regression analysis was conducted by using age, sex, body weight, initial AT activity, DIC score, platelet count, coadministration of heparin, recombinant thrombomodulin, suspected source of infection, surgery, and supplemented AT dose. RESULTS: Supplementation significantly decreased the DIC score in the AT3000 group, leading to the superior resolution of DIC, compared with the results in the AT1500 group (66.7% versus 45.2%, P = 0.007). In addition, the AT3000 group exhibited a better survival than the AT1500 group (77.1% versus 56.4%, P = 0.010). Bleeding events were observed in 6.96% (severe bleeding: 3.04%) in the AT1500 group and 6.52% (severe bleeding, 4.35%) in the AT3000 group (P = 1.000; severe bleeding, P = 0.648). A logistic regression analysis revealed that the use of AT3000 (odds ratio (OR), 2.419; P = 0.025), a higher initial platelet count (OR, 1.054; P = 0.027), and patient age (OR, 0.977; P = 0.045) were significantly correlated with an improved survival. CONCLUSIONS: The AT3000 group exhibited significantly improved rates of survival and recovery from DIC without an increased risk of bleeding, compared with the AT1500 group, among the patients with sepsis-associated DIC and an AT activity of less than 40%.