Thromboprophylaxis with argatroban in critically ill patients with sepsis: a review

Detection of enoxaparin and argatroban by use of the novel viscoelastic coagulometer ClotPro

Owing to the simultaneous increase in the risk of thrombosis and bleeding in critically ill patients, point-of-care-available diagnostic tests to guide parenteral anticoagulation are warranted. We evaluated the detection of enoxaparin and argatroban, two commonly used parenteral anticoagulants, using the novel ClotPro viscoelastic coagulometer. For this experimental in vitro study at a tertiary care academic center, blood samples were drawn from twelve (six female, six male) healthy volunteers without intake of antithrombotic medication and no history of hemostatic disorders. Blood samples were spiked with enoxaparin (IU.ml- 1) and argatroban (µg.ml- 1) at increasing concentrations ranging from 0 to 1. The ClotPro Russell's viper venom (RVV)-test and the ClotPro ecarin (ECA)-test clotting time were performed in parallel with conventional coagulation tests (anti-Xa activity, activated partial thromboplastin time, and diluted thrombin time). We observed a strong correlation between anti-Xa activity and the RVV-test clotting time (r = 0.88 (95% confidence interval (CI) 0.8-0.92; p < 0.001)). Although clotting time cutoff values of 71 and 145 s provided high sensitivity and specificity for detecting anti-Xa activity of ≤ 0.1 and ≥0.6 IU.ml- 1, we found a poor performance at both high and low concentrations. The ECA-test clotting time revealed a very strong correlation with activated partial thromboplastin time (r = 0.96 (95% CI 0.93-0.97; p < 0.001)) and diluted thrombin time (r = 0.97 (95% CI 0.96-0.98; p < 0.001)). The clotting time cutoff values of 86 and 298-431 s provided high sensitivity and specificity for detecting diluted thrombin time values ≤ 0.1 and 0.5-1 µg.ml- 1. Our results suggest that the RVV test is an unreliable method for monitoring enoxaparin treatment, whereas the ECA-test might be an accurate point-of-care alternative for detecting argatroban concentration with potential advantages over standard coagulation tests in terms of point-of-care applicability and turnaround time.

Clinical and economic implications of false-positive heparin-induced thrombocytopenia immunoassays: utility of the 4T score

Heparin-induced thrombocytopenia (HIT) is a prothrombotic condition induced by platelet-activating IgG antibodies that recognize PF4/heparin complexes. Diagnosis of HIT relies on enzyme immunologic assays (EIAs) and functional assays [serotonin release assay (SRA)]. Our institution uses a latex immunoturbidimetric assay (LIA), which has shown a positive-predictive value (PPV) of 55.6%, and a negative-predictive value (NPV) of 99.7%. The low PPV of EIAs/LIAs, in combination with the clinical delay in obtaining results of a SRA, commonly leads to a false-positive diagnosis of HIT and inappropriate treatment. We performed a single-institution retrospective study at a large tertiary center to assess patient management decisions and economic costs following a false-positive HIT (LIA) test. This study found an 89.5% incidence of false-positive HIT (LIA) tests. 97.4% of patients underwent anticoagulation changes. 69.6% of patients were switched to argatroban. Of patients with a false-positive HIT immunoassay (LIA), 42 (40.7%) patients were on a prophylactic dose of anticoagulation at the time of HIT (LIA) positivity, of which 22 (52.4%) were switched to full anticoagulation with either argatroban or fondaparinux. Of the 22 patients switched to full anticoagulation, 15 (68%) had low-probability 4T scores. Seven (8.8%) of patients had bleeding events after HIT (LIA) positivity. All seven patients were switched to argatroban from a full-dose heparin anticoagulation. Five of the seven patients were considered major bleeds. Utilization of argatroban incurred substantial costs, estimated at approximately $73 000 for false-positive HIT cases. False-positive HIT (LIA) tests contribute to unwarranted anticoagulation changes, increased bleeding risks, and substantial healthcare costs. Incorporating the 4T score into diagnostic algorithms may help mitigate these risks by guiding appropriate clinical decisions. Future research should focus on refining diagnostic approaches and standardizing management strategies to improve patient outcomes and cost-effectiveness in HIT diagnosis and management.

Efficacy of antiplatelet drugs combined with Argatroban in treating acute ischemic stroke and its impact on patients' coagulation function and neurological function: a preliminary trial

This retrospective study analyzed the efficacy of combined antiplatelet therapy with Argatroban in treating acute ischemic stroke (AIS) and its impact on patients' coagulation and neurological functions. Clinical data of 113 AIS patients admitted between January 2021 and January 2023 were retrospectively analyzed. Patients were divided into control (n = 56) and observation (n = 57) groups based on treatment interventions. The control group patients were treated with antiplatelet drugs, while the observation group patients received combination therapy with apatinib on the basis of the control group treatment. Compared to the control group, the observation group demonstrated higher clinical efficacy, improved coagulation parameters, reduced stroke severity (measured by NIHSS), enhanced daily living abilities (BI scores), and lowered inflammatory and neural injury markers post-treatment. Adverse reaction incidence was similar between groups. Combining Argatroban with antiplatelet drugs in AIS management showed superior efficacy without increasing adverse effects, suggesting its potential for clinical application.

Anticoagulation with argatroban using hemoclot™ targets is safe and effective in CARDS patients receiving venovenous extracorporeal membrane oxygenation: An exploratory bi-centric cohort study

Direct thrombin inhibitors, including argatroban, are increasingly used for anticoagulation during venovenous extracorporeal membrane oxygenation (VV ECMO). In many centers activated partial thromboplastin time (aPTT) is used for monitoring, but it can be affected by several confounders. The aim of this study was to evaluate the safety and efficacy of anticoagulation with argatroban titrated according to diluted thrombin time targets (hemoclot™ assay) compared to anti-Xa guided anticoagulation with unfractionated heparin (UFH).

METHODS

This cohort study included adults at two tertiary care centers who required VV ECMO for severe COVID-19-related acute respiratory distress syndrome (CARDS). Patients received center-dependent argatroban or UFH for anticoagulation during ECMO. Argatroban was guided following a hemoclot™ target range of 0.4-0.6 μg/ml. UFH was guided by anti-factor Xa (antiXa) levels (0.2-0.3 IU/ml). The primary outcome was safety of argatroban compared to UFH, assessed by time to first clinically relevant bleeding event or death during ECMO. Secondary outcomes included efficacy (time to thromboembolism) and feasibility (proportion of anticoagulation targets within range).

RESULTS

From 2019 to 2021 57 patients were included in the study with 27 patients (47 %) receiving argatroban and 30 patients (53 %) receiving UFH. The time to the first clinically relevant bleeding or death during ECMO was similar between groups (HR (argatroban vs. UFH): 1.012, 95 % CI 0.44-2.35, p = 0.978). Argatroban was associated with a decreased risk for thromboembolism compared to UFH (HR 0.494 (95 % CI 0.26-0.95; p = 0.034)). The overall proportion of anticoagulation within target ranges was not different between groups (46 % (23-54 %) vs. 46 % (37 %-57 %), p = 0.45).

CONCLUSION

Anticoagulation with argatroban according to hemoclot™ targets (0.4-0.6 μg/ml) compared to antiXa guided UFH (0.2-0.3 IU/ml) is safe and may prolong thromboembolism-free time in patients with severe ARDS requiring VV ECMO.

In vitro Effect of Dalteparin and Argatroban on Hemostasis in Critically Ill Sepsis Patients with New-Onset Thrombocytopenia

Thrombocytopenia is common among critically ill sepsis patients, while they also hold an increased risk for thromboembolic events. Thus, the choice of anticoagulant prophylaxis for this patient population is challenging. We investigated the in vitro effect of low-molecular-weight heparin (dalteparin) and direct thrombin inhibitor (argatroban) on the hemostasis in blood from sepsis patients with new-onset thrombocytopenia. Thrombocytopenia was defined as a platelet count drop of ≥30% and/or from >100 × 10 ⁹ /L to 30 to 100 × 10 ⁹ /L within 24 hours prior to inclusion. We included five healthy individuals and ten patients. Analyses of thrombin generation (Calibrated Automated Thrombogram), thrombin-antithrombin (TAT) complex levels, prothrombin fragment 1+2 (F1+2), and rotational thromboelastometry (ROTEM) were performed. Based on dose-response relationships investigated in healthy blood, patient samples were spiked with prophylactic (0.25 IU/mL) and therapeutic (0.75 IU/mL) dalteparin and low (0.25 µg/mL) and high (0.50 µg/mL) argatroban concentrations, each with a sample without anticoagulant. In patients, the endogenous thrombin potential was markedly lower in therapeutic dalteparin samples than in samples without anticoagulant [median (range): 29 (0-388) vs. 795 (98-2121) nM × min]. In high argatroban concentration samples, thrombin lag time was longer than in samples without anticoagulant [median (range): 15.5 (10.5-20.2) versus 5.3 (2.8-7.3) min]. Dalteparin and argatroban both increased clotting time but did not affect maximum clot firmness in the ROTEM INTEM assay. Six patients had elevated TAT and eight patients had elevated F1 + 2. In conclusion, dalteparin mainly affected the amount of thrombin generated and argatroban delayed clot initiation in critically ill sepsis patients with new-onset thrombocytopenia. Neither anticoagulant affected clot strength.

Antithrombin as Therapeutic Intervention against Sepsis-Induced Coagulopathy and Disseminated Intravascular Coagulation: Lessons Learned from COVID-19-Associated Coagulopathy

Recent research has contributed significantly to our understanding of the pathogenesis of acute disseminated intravascular coagulation. COVID-19 can be considered as a new underlying condition of disseminated intravascular coagulation. In this narrative review, current evidence is presented regarding biomarker differences between sepsis-induced and COVID-19-associated coagulopathies, supporting the importance of acquired antithrombin deficiency in the early differential diagnosis of septic coagulopathy and its potential impact on treatment with endogenous anticoagulants. Establishing new scoring systems for septic coagulopathy in combination with endogenous anticoagulant biomarker activities may allow for the identification of those in the heterogeneous population of sepsis patients who are more likely to benefit from targeted specific treatment interventions.