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.

Association of Argatroban Dose With Coagulation Laboratory Test in Patients on Extracorporeal Membrane Oxygenation: Activated Clotting Time vs Activated Partial Thromboplastin Time

BACKGROUND

Only some studies have directly compared and analyzed the roles of activated partial thromboplastin time (aPTT) and activated clotting time (ACT) in coagulation monitoring during argatroban administration.

OBJECTIVES

This study aims to assess the correlation of argatroban dose with ACT and aPTT values and to identify the optimal coagulation test for argatroban dose adjustment.

METHODS

We evaluated 55 patients on extracorporeal membrane oxygenation (ECMO) who received argatroban for more than 72 hours. The correlation between argatroban dose and aPTT and ACT values was evaluated. To compare argatroban dose and bleeding events according to liver dysfunction, the patients were divided into 2 groups based on alanine aminotransferase and total bilirubin.

RESULTS

Among the 55 patients, a total of 459 doses and coagulation tests were evaluated. The aPTT and ACT values showed a weak correlation with argatroban dose, with the Pearson correlation coefficients of 0.261 (P < 0.001) and 0.194 (P = 0.001), respectively. The agreement between the target 150 to 180 seconds for ACT and 55 to 75 seconds for aPTT was observed in 140 patients (46.1%). Twenty-four patients (43.6%) had liver dysfunction when they started argatroban. The median argatroban dose was lower in the liver dysfunction group than in the control group (0.094 mcg/kg/min vs 0.169 mcg/kg/min, P = 0.020). Difference was not observed between the 2 groups in the amount of red blood cell (0.47 vs 0.43 pack, P = 0.909) and platelet (0.60 vs 0.08 pack, P = 0.079) transfusion per day.

CONCLUSION AND RELEVANCE

A weak correlation was observed between argatroban dose and the aPTT and ACT values. However, the agreement between aPTT and ACT was only 46.1% regarding the scope of target range. Further research is necessary to determine how to assess the optimal argatroban dose for patients administered argatroban while undergoing ECMO at the intensive care unit.

The effect of argatroban on early neurological deterioration and outcomes in minor ischemic stroke: preliminary findings

Background

Minor ischemic stroke (MIS) is associated with early neurological deterioration (END) and poor prognosis. Here, we investigated whether argatroban administration can mitigate MIS-associated END and improve functional outcomes by monitoring activated partial thrombin time (APTT).

Methods

Data were collected for patients with MIS admitted to our hospital from January 2019 to December 2022. Patients were divided into a dual antiplatelet therapy (DAPT) group (aspirin + clopidogrel) and an argatroban group (aspirin + argatroban). Those in the latter group who achieved a target APTT of 1.5-3-fold that of baseline and <100 s at 2 h after argatroban infusion were included in the argatroban subgroup. The primary outcome was the END rate of the DAPT group versus that of the argatroban group or the argatroban subgroup. Secondary outcomes included the proportion of patients with modified Rankin Scale (mRS) 0-2 at 7 and 90 days. In addition, baseline date were compared between patients with and without END in the argatroban group.

Results

363 patients were included in the DAPT group and 270 in the argatroban group. There were no significant differences in any above outcome between them. 207 pairs were included in the DAPT group and the argatroban subgroup after 1:1 propensity score matching (PSM). Significant differences were observed in the proportion of END (OR, 2.337; 95% CI, 1.200-4.550, p = 0.011) and mRS 0-2 at 7 days (OR, 0.624; 95% CI, 0.415-0.939, p = 0.023), but not in mRS 0-2 at 90 days or the hemorrhagic events between the two groups. In the argatroban group, univariate analysis showed that the rate of diabetes (OR, 2.316; 95% CI, 1.107-4.482, p = 0.023), initial random blood glucose (OR, 1.235; 95% CI, 1.070-1.425, p = 0.004), drinking history (OR, 0.445; 95% CI, 0.210-0.940, p = 0.031) or those reaching the target APTT (OR, 0.418; 95% CI, 0.184-0.949, p = 0.033) was significantly different among patients with and without END. However, there were no statistical differences in these parameters between them following multivariate analysis.

Conclusion

In patients with MIS, argatroban administration and reaching the target APTT can reduce the incidence of END and improve short-term functional prognosis.

Argatroban promotes recovery of spinal cord injury by inhibiting the PAR1/JAK2/STAT3 signaling pathway

Argatroban is a synthetic thrombin inhibitor approved by U.S. Food and Drug Administration for the treatment of thrombosis. However, whether it plays a role in the repair of spinal cord injury is unknown. In this study, we established a rat model of T10 moderate spinal cord injury using an NYU Impactor Moder III and performed intraperitoneal injection of argatroban for 3 consecutive days. Our results showed that argatroban effectively promoted neurological function recovery after spinal cord injury and decreased thrombin expression and activity in the local injured spinal cord. RNA sequencing transcriptomic analysis revealed that the differentially expressed genes in the argatroban-treated group were enriched in the JAK2/STAT3 pathway, which is involved in astrogliosis and glial scar formation. Western blotting and immunofluorescence results showed that argatroban downregulated the expression of the thrombin receptor PAR1 in the injured spinal cord and the JAK2/STAT3 signal pathway. Argatroban also inhibited the activation and proliferation of astrocytes and reduced glial scar formation in the spinal cord. Taken together, these findings suggest that argatroban may inhibit astrogliosis by inhibiting the thrombin-mediated PAR1/JAK2/STAT3 signal pathway, thereby promoting the recovery of neurological function after spinal cord injury.

Argatroban as an Add-On to rtPA in Acute Ischemic Stroke: A Systematic Review and Meta-Analysis

Current treatment options for acute ischemic stroke, including intravenous thrombolysis (IVT) and mechanical thrombectomy, have undoubtedly revolutionized stroke care. The need for additional treatment options has brought into the light direct thrombin inhibitors (DTIs) and, specifically, argatroban as a promising candidate. However, there is uncertainty regarding the safety of adding argatroban to IVT, mainly due to the increased hemorrhagic risk. In this study, we performed a systematic review and meta-analysis examining the safety and efficacy of argatroban as an add-on treatment for IVT. The following databases were searched from inception until the 14th of May 2023: Pubmed/MEDLINE, ClinicalTrials.gov, the EU Clinical Trials Register, EMBASE/Scopus, and the Cochrane Library. Only randomized clinical trials (RCTs) enrolling patients with acute ischemic stroke who underwent IVT evaluating the add-on use of any DTIs were selected for the systematic review and further meta-analysis. The PRISMA guidelines were followed at all stages. Four studies with argatroban were included in the final analysis. Analysis of risk ratio and relative risk shows that the add-on therapy with argatroban seems to be effective and favors a good clinical outcome (mRS 0-2) at 90 days, similar to that of alteplase. All studies showed a low pooled incidence of symptomatic intracerebral hemorrhage (5%), parenchymal hematoma (3%), and other major bleeding (1%). Argatroban as an add-on treatment to IVT seems not to be associated with excessive bleeding risk; however, its efficacy remains unproven. According to this synopsis of the currently available evidence, it is premature to use argatroban as an add-on to IVT treatment outside the current clinical trial setting.

Bioprosthetic valve thrombosis after transcatheter aortic valve replacement and pulmonary embolism due to heparin-induced thrombocytopenia: a case report

Background

Bioprosthetic valve thrombosis is a complication of transcatheter aortic valve replacement (TAVR). It is believed to be platelet independent, mainly driven by contact phase activation, and more likely to be targeted by oral anticoagulant (OAC).

Case summary

We report case of an 86-year-old man with history of TAVR, who presented an early TAVR aortic valve thrombosis occurring in the context of heparin-induced thrombocytopenia (HIT) and pulmonary embolism. The patient rapidly recovered and was discharged 17 days after readmission. OAC by Coumadin was administered for 3 months. Chest tomography after 3 months showed the disappearance of the hypoattenuated leaflet thickening.

Discussion

Although HIT has been fully described and is known for being a prothrombotic disorder, this is the first case report of aortic valve thrombosis after TAVR due to HIT. HIT is rare but possibly lethal. Diagnosis is based on pre-test probability evaluation with the 4T clinical score and confirmation with laboratory evidence of anti-PF4/heparin complexes and positivity of a functional test. Management of HIT is based on heparin discontinuation, and treatment of thrombotic complication with direct anti-IIa inhibitor or anti-Xa inhibitor. According to our knowledge, this case represents the first report of bioprosthetic valve thrombosis after TAVR due to HIT.

Heparin induced thrombocytopenia in pregnancy: A therapeutic challenge case report and literature review

The anticoagulants of choice for the prevention and treatment of venous thromboembolic disease during pregnancy are unfractionated heparin and low-molecular-weight heparin. Heparin-induced thrombocytopenia (HIT) is introduced as a rare but critical side effect of heparin products raising the thromboembolic event paradoxically. Here, we present a case of HIT in pregnancy with challenging management due to coincidence of lupus anticoagulant (LA) and limited anticoagulant options in the pharmaceutical market of our country of residence. We describe a 6-week pregnant patient with deep venous thrombosis (DVT) and pulmonary thromboembolism (PTE), which developed HIT during antenatal care. Therapeutic anticoagulation was initiated with argatroban, then switched to apixaban due to limited access to argatroban. Another therapeutic challenge was the concurrent incidence of LA. The interdisciplinary care team decided on adding up warfarin and scheduled termination at 12 weeks regarding the hazardous condition of the patient. We also reviewed related case literature to convey a new insight into managing pregnancy-related HIT. HIT is a pro-coagulatory and lethal complication associated with heparin therapy that can be diagnosed by clinical suspicion, the 4T score system, and confirmatory laboratory analyses. Alternative anticoagulation is the cornerstone of the treatment and an interdisciplinary plan will be worthwhile to make the best clinical decision regarding the critical situation and least the thromboembolic events mortality during pregnancy.

Membrane oxygenator longevity was higher in argatroban-treated patients undergoing vvECMO

BACKGROUND

In severe acute respiratory distress syndrome (ARDS), venovenous extracorporeal membrane oxygenation (vvECMO) can be a lifesaver. However, anticoagulation therapy is mandatory because the nonendothelial extracorporeal surface increases the risk of thromboembolic problems. Heparin is still the most common anticoagulant, but argatroban could be an alternative. This work investigates whether argatroban offers a therapeutic advantage over heparin during vvECMO.

METHODS

We performed a retrospective cohort study of patients who underwent vvECMO for severe ARDS and received heparin or argatroban as anticoagulation therapy. Demographic variables, intensive care unit (ICU) treatment and outcome parameters were evaluated. The primary outcome parameter was the operating time of the membrane oxygenator normalized to the duration of vvECMO treatment. Secondary outcome parameters were transfusion requirements normalized to the duration of vvECMO therapy.

RESULTS

Fifty seven patients from January 2019 to February 2021 underwent vvECMO and were included in this study. Thirty three patients received heparin and 24 patients argatroban as anticoagulatory therapy. The groups did not differ in demographics, ICU scoring systems, or comorbidities. Platelet counts and partial prothrombin time did not differ between the two groups during the first 6 days of vvECMO. The argatroban group had lower requirements for red blood cells, platelets and fresh frozen plasma. The mean runtime of the individual membrane oxygenator increased from 12.3 days (heparin group) to 16.6 days in the argatroban group.

CONCLUSIONS

Our findings suggest that argatroban can be considered as anticoagulant during vvECMO.

Novel Monitoring and Dose Adjustment of Argatroban, a Direct Thrombin Inhibitor, to Maintain Therapeutic Anticoagulation in a Patient With Antiphospholipid Antibody Syndrome, Heparin-Induced Thrombocytopenia, and COVID-19 Pneumonia

In patients who require systemic anticoagulation, a reliable monitoring method is required to ensure anticoagulation is maintained within the correct therapeutic window and patients are treated appropriately. When titrating direct thrombin inhibitors (DTIs), dilute thrombin time (dTT) measurements have been demonstrated to be more reliable and accurate than activated partial thromboplastin time (aPTT) measurements and thus often the preferred DTI assessment. However, a clinical need arises when both dTT measurements are not readily available and aPTT measurements are unreliable.

CASE SUMMARY

A 57-year-old woman with a history of antiphospholipid antibody syndrome, heparin-induced thrombocytopenia, and multiple prior deep venous thromboses and pulmonary emboli was admitted with COVID-19 pneumonia and intubated due to hypoxic respiratory failure. Argatroban was initiated in place of her home medication warfarin. However, the patient had a prolonged aPTT value at baseline and overnight dTT assay measurements were limited at our institution. A multidisciplinary team of hematology and pharmacy clinicians created a modified patient-specific aPTT target range and argatroban dosing was titrated accordingly. Subsequent aPTT values in the modified target range corresponded to therapeutic dTT values, indicating therapeutic anticoagulation was successfully achieved and maintained. Patient blood samples were additionally evaluated retrospectively using an investigational novel point-of-care test that detected and quantified the argatroban anticoagulant effect.

CONCLUSIONS

Therapeutic anticoagulation with a DTI in a patient with unreliable aPTT measurements can be achieved with use of a modified patient-specific aPTT target range. Early validation of an investigational rapid testing alternative for DTI monitoring is promising.

Efficacy and Prognosis of Adjuvant Argatroban Treatment in Acute Ischemic Stroke Patients with Early Neurological Deterioration

BACKGROUND

The therapeutic outcomes for acute ischemic stroke (AIS) with early neurological deterioration (END) are adverse. Argatroban is a novel direct thrombin inhibitor, which is safe in the treatment of AIS, but its efficacy is controversial. This study sought to assess the therapeutic effect of argatroban as an adjunct to aspirin in the treatment of AIS patients with END. Patients' prognosis for the presence of END was also evaluated.

METHODS

Overall, 166 AIS patients with END were included in the study from June 2018 to June 2021 in The Affiliated Zhangjiagang Hospital of Soochow University. Patients were divided in the control group (aspirin alone) and the study group (aspirin combined with argatroban). General data of the patients were collected. Clinical indexes such as the modified Edinburgh-Scandinavian stroke scale (MESSS), and the serum fibrinogen (FIB) and neuropeptide Y (NPY) levels before and after treatment were also collected. Correlations between prognosis and general data, and FIB and NPY levels in AIS patients with END were analyzed by multivariate logistic regression. The performance of FIB and NPY levels in predicting patients' prognosis was further analyzed using receiver operating characteristic (ROC) curves.

RESULTS

There was no significant difference in the general data, such as sex, age, course of disease and basic diseases between the 2 groups. After treatment, the MESSS score (13.08 ± 3.24 vs. 16.48 ± 3.32, p < 0.001), serum FIB level (2.72 ± 0.81 vs. 3.52 ± 0.71, p < 0.001), and NPY level (121.28 ± 17.34 vs. 152.09 ± 18.25, p < 0.001) of the study group was significantly lower than that of the control group. A further analysis revealed that the serum FIB (OR, odds ratio = 2.296, 95% confidence interval, CI: 1.437-3.669, p = 0.001) and NPY (OR = 1.020, 95% CI: 1.002-1.039, p = 0.031) levels were independent risk factors of patients' prognosis for the presence of END.

CONCLUSIONS

Aspirin combined with argatroban significantly improved neurological impairment of AIS patients with END, which is worthy of clinical application.

Anticoagulation Management during Extracorporeal Membrane Oxygenation-A Mini-Review

Extracorporeal membrane oxygenation (ECMO) has been established as a life-saving technique for patients with the most severe forms of respiratory or cardiac failure. It can, however, be associated with severe complications. Anticoagulation therapy is required to prevent ECMO circuit thrombosis. It is, however, associated with an increased risk of hemocoagulation disorders. Thus, safe anticoagulation is a cornerstone of ECMO therapy. The most frequently used anticoagulant is unfractionated heparin, which can, however, cause significant adverse effects. Novel drugs (e.g., argatroban and bivalirudin) may be superior to heparin in the better predictability of their effects, functioning independently of antithrombin, inhibiting thrombin bound to fibrin, and eliminating heparin-induced thrombocytopenia. It is also necessary to keep in mind that hemocoagulation tests are not specific, and their results, used for setting up the dosage, can be biased by many factors. The knowledge of the advantages and disadvantages of particular drugs, limitations of particular tests, and individualization are cornerstones of prevention against critical events, such as life-threatening bleeding or acute oxygenator failure followed by life-threatening hypoxemia and hemodynamic deterioration. This paper describes the effects of anticoagulant drugs used in ECMO and their monitoring, highlighting specific conditions and factors that might influence coagulation and anticoagulation measurements.

Heparin-Induced Thrombocytopenia at the Emergency Department Due to Intermittent Heparin Flush in a Patient Undergoing Stem Cell Transplant

Heparin-induced thrombocytopenia (HIT) is an adverse reaction to heparin products, but not warfarin. HIT usually occurs 5‒10 days after exposure to heparin. Here, we report a case of HIT with multiple thrombotic events and severe thrombocytopenia resulting from intermittent intravenous heparin flushes for maintenance of a newly placed subclavian central venous catheter (CVC) for stem cell transplant. The patient is a woman in her forties with multiple myeloma who presented to the emergency department (ED) with dyspnea, pleuritic-type chest pain, hemoptysis, and worsening left-leg swelling. Heparin had been used to flush the CVC. Her platelet count began dropping approximately one week after insertion. The patient was receiving other medications known to cause thrombocytopenia. She had undergone multiple platelet transfusions. In the ED, her lab results showed thrombocytopenia), anemia; renal insufficiency; and elevated troponin, prothrombin time, and D-dimer levels. Because of the hemoptysis and thrombocytopenia, she initially received platelet transfusion and oxygen. She was found to have deep vein thrombosis of the lower extremity and started a referral to interventional radiology for inferior vena cava (IVC) filter placement. However, further review and consultation of the Benign Hematology service, discussion about the timing of decreased platelet count shortly after CVC placement and heparin administration, and the presence of thrombosis, suggested a high pre-test probability of HIT. Anticoagulation with argatroban was initiated, and IVC filter insertion was canceled. Further workup confirmed HIT diagnosis and saddle pulmonary embolism. During the patient's hospitalization, her platelets continued to improve and reached baseline upon discharge. She was transitioned to fondaparinux at the time of discharge. A few weeks later, she had successful stem cell transplantation. Emergency physicians treating patients with thrombocytopenia receiving heparin, even in small amounts, should consider the possibility of HIT and be familiar with its management.

Direct Thrombin Inhibition in Extracorporeal Membrane Oxygenation

Extracorporeal membrane oxygenation (ECMO) is a widely used technique to provide circulatory and/or respiratory support in critically ill patients. ECMO treatment usually necessitates systemic anticoagulation. Unfractionated Heparin (UFH) is a commonly used anticoagulant in patients on ECMO support. In situations where UFH is contraindicated, alternative anticoagulation strategies can be applied, such as the use of direct thrombin inhibitors (DTI). Bivalirudin and argatroban are the most widely used DTIs. In this report we give account of the current evidence regarding dosing, monitoring and complications associated with the use of these agents in ECMO dependent patients.

Caution in Using the Activated Partial Thromboplastin Time to Monitor Argatroban in COVID-19 and Vaccine-Induced Immune Thrombocytopenia and Thrombosis (VITT)

Introduction

Argatroban is licensed for patients with heparin-induced thrombocytopenia and is conventionally monitored by activated partial thromboplastin time (APTT) ratio. The target range is 1.5 to 3.0 times the patients’ baseline APTT and not exceeding 100 s, however this baseline is not always known. APTT is known to plateau at higher levels of argatroban, and is influenced by coagulopathies, lupus anticoagulant and raised FVIII levels. It has been used as a treatment for COVID-19 and Vaccine-induced Immune Thrombocytopenia and Thrombosis (VITT). Some recent publications have favored the use of anti-IIa methods to determine the plasma drug concentration of argatroban.

Methods

Plasma of 60 samples from 3 COVID-19 patients and 54 samples from 5 VITT patients were tested by APTT ratio and anti-IIa method (dilute thrombin time dTT). Actin FS APTT ratios were derived from the baseline APTT of the patient and the mean normal APTT.

Results

Mean APTT ratio derived from baseline was 1.71 (COVID-19), 1.33 (VITT) compared to APTT ratio by mean normal 1.65 (COVID-19), 1.48 (VITT). dTT mean concentration was 0.64 µg/ml (COVID-19) 0.53 µg/ml (VITT) with poor correlations to COVID-19 baseline APTT ratio r² = 0.1526 p <0.0001, mean normal r² = 0.2188 p < 0.0001; VITT baseline APTT ratio r² = 0.04 p < 0.001, VITT mean normal r² = 0.0064 p < 0.001.

Conclusions

We believe that dTT is a superior method to monitor the concentration of argatroban, we have demonstrated significant differences between APTT ratios and dTT levels, which could have clinical impact. This is especially so in COVID-19 and VITT.

[Performance evaluation of the STA ECA-II reagent for specific assay of anti-IIa activity of argatroban]

Argatroban is indicated in the management of patients with suspicion of Heparin-Induced Thrombocytopenia. Biological monitoring of argatroban can be carried out using the activated partial thromboplastin time (APTT) or the measurement of the anti-IIa activity. However, APTT is susceptible to many interferences making its use unsuitable. The objective of this work is to define and verify the performance of a dosing protocol for the anti-IIa activity of the argatroban from the STA ECA-II reagent (Diagnostica Stago) and compare them to the Hemoclot Thrombin Inhibitor proposed by Hyphen Biomed based on diluted thrombin time. Calibration curve shows a good correlation between anti-IIa activity and the coloration level of the reaction medium over the concentration range studied (0 to 2 μg/mL). The analytical performances obtained at the native dilution of 1/10th are excellent, both in terms of repeatability and reproducibility with a coefficient of variation below 10%. Automatic relaunch at 1/20th for sample concentrations greater than 2 μg/mL does not impact this performance level. We obtain a limit of quantification below 0.2 μg/mL. The comparison of the methods gave consistent and well-correlated results on a wide range of concentrations (0.3 to 4 μg/mL). The use of the STA ECA-II reagent is a valuable alternative to APTT for biological monitoring of anticoagulant action of argatroban.

Laboratory methods for monitoring argatroban in heparin-induced thrombocytopenia

INTRODUCTION

The Summary of Product Characteristics for the direct thrombin inhibitor argatroban states monitoring should be by activated partial thromboplastin time (APTT), with a target range of 1.5-3.0 times the patients' baseline APTT. APTT may be influenced by coagulopathies, lupus anticoagulant and raised FVIII levels. Previous studies have shown sensitivity differences of APTT reagents to argatroban. Some recent publications have favoured the use of anti-IIa methods to determine the plasma drug concentration of argatroban. This study aims to compare the anti-IIa assays: Hemoclot thrombin inhibitor assay (HTI) and Ecarin chromogenic assay (ECA) alongside the APTT.

METHODS

Residual plasma of 25 samples from 8 patients (3 with COVID-19 and HIT: n = 18, 5 with HIT: n = 7) was tested at two sites: site A: Sysmex CS5100 by HTI and APTT (Actin FS and SynthASil), and also on Stago STA Compact Max: ECA and APTT (CK Prest); and site B: Stago STA R Max 2 by ECA and APTT (Cephascreen).

RESULTS

Mean APTT ratio was 1.96 (Actin FS), 1.84 (SynthASil), 1.59 (CK Prest) and 2.48 (Cephascreen). Mean argatroban concentration by HTI was 0.60 µg/mL and by ECA was 0.65 µg/mL (site A) and 0.70 µg/mL (site B). There was a poor correlation to HTI in APTT ratios (range r²  = .0235-0.4181) with stronger correlations between ECA methods to HTI (r²  = .8998 site A, r²  = .8734 site B).

CONCLUSION

This study confirms previous publications on the unsuitability of APTT and expands this by being multisited and included APTT reagents that use mechanical clot detection. Both anti-IIa methods are more suitable.

GFHT Proposals On The Practical Use Of Argatroban - With Specifics Regarding Vaccine-Induced Immune Thrombotic Thrombocytopaenia (VITT)

Argatroban is a direct anti-IIa (thrombin) anticoagulant, administered as a continuous intravenous infusion; it has been approved in many countries for the anticoagulant management of heparin-induced thrombocytopaenia (HIT). Argatroban was recently proposed as the non-heparin anticoagulant of choice for the management of patients diagnosed with Vaccine-induced Immune Thrombotic Thrombocytopaenia (VITT). Immunoglobulins are also promptly intravenously administered in order to rapidly improve platelet count; concomitant therapy with steroids is also often considered. An ad hoc committee of the French Working Group on Haemostasis and Thrombosis members has worked on updated and detailed proposals regarding the management of anticoagulation with argatroban, based on previously released guidance for HIT, and adapted for VITT. In case of VITT, the initial dose to be preferred is 1.0 µg x kg^-1 x min^-1, with further dose-adjustments based on iterative and frequent clinical and laboratory assessments. It is strongly advised to involve a health practitioner experienced in the management of difficult cases in haemostasis. The first laboratory assessment should be performed 4 hours after the initiation of argatroban infusion, with further controls at 2-4-hour intervals until steady state, and at least once daily thereafter. Importantly, full anticoagulation should be rapidly achieved in case of widespread thrombosis. Cerebral vein thrombosis (which is typical of VITT) should not call for an overly cautious anticoagulation scheme. Argatroban administration requires baseline laboratory assessment and should rely on an anti-IIa assay to derive argatroban plasma levels using a dedicated calibration, with a target range between 0.5 and 1.5 µg/mL. Target argatroban plasma levels can be refined based on meticulous appraisal of risk factors for bleeding and thrombosis, on frequent reassessments of clinical status with appropriate vascular imaging, and on the changes in daily platelet counts. Regarding the use of aPTT, baseline value and possible causes for alterations of the clotting time must be taken into account. Specifically, in case of VITT, an aPTT ratio (patient's / mean normal clotting time) between 1.5 and 2.5 is suggested, to be refined according to the sensitivity of the reagent to the effect of a direct thrombin inhibitor. The sole use of aPTT is discouraged: one has to resort to a periodical check with an anti-IIa assay at least, with the help of a specialised laboratory if necessary. Dose modifications should proceed in a stepwise manner with 0.1 to 0.2 µg x kg^-1 x min^-1 up- or downward changes, taking into account the initial dose, laboratory results, and the whole individual setting. Nomograms are available to adjust the infusion rate. Haemoglobin level, platelet count, fibrinogen plasma level and liver tests should be periodically checked, depending on the clinical status, the more so when unstable.

Argatroban for Anticoagulation in Patients Requiring Venovenous Extracorporeal Membrane Oxygenation in Coronavirus Disease 2019

A significant proportion of patients with coronavirus disease 2019 requiring venovenous extracorporeal membrane oxygenation at our institution demonstrated heparin resistance, which in combination with a heparin shortage resulted in the transition to argatroban with or without aspirin as an alternative anticoagulation strategy. The optimal anticoagulation strategy for coronavirus disease 2019 patients requiring venovenous extracorporeal membrane oxygenation is unknown, and therefore, we sought to evaluate the efficacy and safety of argatroban with or without aspirin as an alternative anticoagulation strategy in this patient population.

DESIGN

Retrospective cohort.

SETTING

Single-center tertiary-care facility in Fort Sam Houston, TX, from 2020 to 2021.

PATIENTS

Twenty-four patients who were cannulated for venovenous extracorporeal membrane oxygenation due to respiratory failure secondary to coronavirus disease 2019.

INTERVENTIONS

Argatroban, with or without aspirin, was substituted for heparin in coronavirus disease 2019 patients requiring venovenous extracorporeal membrane oxygenation.

MEASUREMENTS AND MAIN RESULTS

Eighty percent of our coronavirus disease 2019 patients requiring venovenous extracorporeal membrane oxygenation demonstrated heparin resistance, and patients who were initially started on heparin were significantly more likely to require a change to argatroban than vice versa due to difficulty achieving or maintaining therapeutic anticoagulation goals (93.4% vs 11.1%; p < 0.0001). The time to reach the therapeutic anticoagulation goal was significantly longer for patients who were initially started on heparin in comparison with argatroban (24 vs 6 hr; p = 0.0173). Bleeding and thrombotic complications were not significantly different between the two cohorts.

CONCLUSIONS

Argatroban, with or without aspirin, is an effective anticoagulation strategy for patients who require venovenous extracorporeal membrane oxygenation support secondary to coronavirus disease 2019. In comparison with heparin, this anticoagulation strategy was not associated with a significant difference in bleeding or thrombotic complications, and was associated with a significantly decreased time to therapeutic anticoagulation goal, likely as a result of high rates of heparin resistance observed in this patient population.

Evaluating the safety and efficacy of argatroban locking solution in the prevention of the dysfunction of haemodialysis central venous catheters: a study protocol for a randomized controlled trial

BACKGROUND

Use of anticoagulant as lock solutions is an important method to maintain the function of haemodialysis (HD) central venous catheters (CVCs), and the common anticoagulants heparin and citrate are not suitable for some patients. Argatroban can inhibit thrombin directly, has a definite anticoagulant effect, and is expected to be a new anticoagulant for CVC lock solutions.

METHODS

A total of 60 HD patients with non-tunnelled or tunnelled CVCs will be randomly assigned to two groups: an argatroban group and a control group. The participants will be given argatroban 0.5 mg/mL or unfractionated heparin (UFH) 1,000 U/mL locked post-dialysis instilled into the CVC lumens and followed up for 2 weeks. Data on demographic and general clinical information, laboratory examination, adverse events, adverse reactions and serious adverse events in the two groups will be collected. The differences in coagulation indexes at 30 min following catheter lock will be compared. The thrombosis rate, infection rate and percentage of catheter-days in the two groups will be observed. The primary outcomes include: efficacy assessments of combined outcome events: (I) rates of cumulative catheter survival in the 2-week HD session (the standard of catheter survival was catheter mean blood flow ≥250 mL/min); (II) rates of cumulative survival free of catheter thrombosis in the 2-week HD session. The second outcomes include: catheter dysfunction, the variation value (seconds) in activated partial thromboplastin time (aPTT) at 30 min following catheter locking and aPTT before next dialysis, catheter-associated bleeding, and catheterassociated infections.

DISCUSSION

At present, there is no clinical study of argatroban as a CVC lock solution. This study will explore the efficacy and safety of the argatroban as locking solution in the prevention of the dysfunction of HD CVCs to provide evidence for further research.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR1800017105. Registered 12 July, 2018 (prospectively registered, http://www.chictr.org.cn/showproj.aspx?proj=29054).

Heparin induced thrombocytopenia: position paper from the Italian Society on Thrombosis and Haemostasis (SISET)

Heparin induced thrombocytopenia (HIT) is a rare immune mediated adverse drug reaction occurring after exposure to heparin. It is a serious and potentially fatal condition, which may be associated with the development of arterial or venous thrombotic events. Although known for many years, HIT is still often misdiagnosed. Pre- test clinical probability, screening for anti-PF4/heparin antibodies and documentation of their platelet activating capacity are the cornerstones of diagnosis. However, both clinical algorithms and test modalities have limited predictive values and limited diffusion so that the diagnosis and management is challenging in the clinical practice. For this reason, there is an unmet need for novel rational non-anticoagulant therapies based on the pathogenesis of HIT.The present paper reports the position of the Italian Society on Haemostasis and Thrombosis (SISET) in order to increase awareness of HIT among clinicians and other health care professionals and to provide information on the most appropriate management.

Anticoagulation Resumption in a Patient With Mechanical Heart Valves, Antithrombin Deficiency, and Hemorrhagic Transformation Following Thrombectomy After Ischemic Stroke

Anticoagulation is essential for patients undergoing mechanical heart valve replacement; however, the timing to reinitiate the anticoagulant could be a dilemma that imposes increased risk for bleeding events in patients suffering from the life-threatening hemorrhagic transformation (HT) after ischemic stroke. Such a situation was presented in this case report. A 71-year-old woman was transferred directly to the Neurocritical Care Unit because of a HT that occurred following the mechanical thrombectomy for ischemic stroke. Since she had a history of prosthetic metallic valve replacement, how the anticoagulating therapy could balance the hemorrhagic and thrombotic risks was carefully evaluated. On day 6 after the onset of hemorrhage transformation, the laboratory results of coagulation and fibrinolysis strongly suggested thrombosis as well as antithrombin deficiency. The short-acting and titratable anticoagulant argatroban was immediately initiated at low dose, and thrombosis was temporarily terminated. On day 3 of anticoagulation resumption, argatroban was discontinued for one dose when the prothrombin time and activated partial thromboplastin time significantly prolonged after argatroban infusion. Aortic valve thrombosis was detected the next day. The anticoagulation was then strengthened by dose adjustment to keep mitral valve intact, to stabilize the aortic valve thrombosis, and to decrease the aortic flow rate. The intravenous argatroban was transited to oral warfarin before the patient was discharged. This study is the first report of administering argatroban and titrating to its appropriate dose in the patient with valve thrombosis, antithrombin deficiency, and HT after mechanical thrombectomy for acute ischemic stroke. Notably, the fluctuations argatroban brings to the coagulation test results might not be interpreted as increased bleeding risk. This case also suggested that the reported timing (day 6 to day 14 after hemorrhage) of anticoagulant resumption in primary intracerebral hemorrhage with mechanical valves might be late for some patients with HT.

The multiarm optimization of stroke thrombolysis phase 3 acute stroke randomized clinical trial: Rationale and methods

BACKGROUND

Intravenous recombinant tissue plasminogen activator is the only proven effective medication for the treatment of acute ischemic stroke. Two approaches that may augment recombinant tissue plasminogen activator thrombolysis and prevent arterial reocclusion are direct thrombin inhibition with argatroban and inhibition of the glycoprotein 2b/3a receptor with eptifibatide.

AIM

The multi-arm optimization of stroke thrombolysis trial aims to determine the safety and efficacy of intravenous therapy with argatroban or eptifibatide as compared with placebo in acute ischemic stroke patients treated with intravenous recombinant tissue plasminogen activator within 3 h of symptom onset.

SAMPLE SIZE ESTIMATE

A maximum of 1200 randomized subjects to test the superiority of argatroban or eptifibatide to placebo in improving 90-day modified Rankin scores.

METHODS AND DESIGN

Multiarm optimization of stroke thrombolysis is a multicenter, multiarm, adaptive, single blind, randomized controlled phase 3 clinical trial conducted within the National Institutes of Health StrokeNet clinical trial network. Patients treated with 0.9 mg/kg intravenous recombinant tissue plasminogen activator within 3 h of stroke symptom onset are randomized to receive intravenous argatroban (100 µg/kg bolus followed by 3 µg/kg/min for 12 h), intravenous eptifibatide (135 µg/kg bolus followed by 0.75 µg/kg/min infusion for 2 h) or IV placebo. Patients may receive endovascular thrombectomy per usual care.

STUDY OUTCOMES

The primary efficacy outcome is improved modified Rankin score assessed at 90 days post-randomization.

DISCUSSION

Multiarm optimization of stroke thrombolysis is an innovative and collaborative project that is the culmination of many years of dedicated efforts to improve outcomes for stroke patients.

[Complex management of type 2 heparin-induced thrombocytopenia in patients with major bleeding tendency: two case report]

Type 2 heparin-induced thrombocytopenia (HIT 2) is a rare pro-thrombotic disorder occurring in patients treated with heparin. It is defined as a clinical-biological syndrome associating the sudden onset of a thrombocytopenia, characterized by a drop of more than 50% of the initial platelet count, and thrombosis. We report two cases of HIT 2 occurring in patients with major bleeding tendency. The first HIT occurred in a patient whose management, in accordance with current guidelines, made it possible to control the thrombocytopenia and the anticoagulation despite the complexity of adapting and monitoring treatments in the context of recent cerebral hemorrhage. The second refers to an autoimmune HIT, which occurred in a patient whose management required the use of alternative therapies to the standard treatments suggested for HIT 2, to correct the severe refractory thrombocytopenia.

Thrombolysis and use of argatroban for the treatment of massive pulmonary embolism following anticoagulation failure in a patient with COVID-19

Purpose

Successful use of alteplase and argatroban to treat a patient with coronavirus disease 2019 (COVID-19)–associated massive pulmonary embolism with cardiac arrest is reported.

Summary

This case report describes a 42-year-old male with COVID-19 who developed a massive pulmonary embolism resulting in cardiac arrest after suspected failure of low-molecular-weight heparin therapy for a deep venous thrombosis. Administration of two 50-mg doses of intravenous alteplase resulted in return of spontaneous circulation, and low-dose argatroban was used as follow-up anticoagulation therapy without complications. This is the first case report of use of argatroban in a patient with COVID-19 with cardiac arrest–associated massive pulmonary embolism after failure of previous anticoagulation efforts.

Conclusion

Argatroban may be used as an alternate anticoagulation strategy in COVID-19 patients who fail low-molecular weight therapy. A risk versus benefit discussion should be had regarding appropriateness of therapy as well as dosing. More data is needed to understand the unique hypercoagulable condition in COVID-19 patients as well as research that further highlights the role of argatroban and bivalirudin therapy in this patient population.

[Examination of the Relationship between Worse Symptom and Differences Route during Administration of Argatroban in Acute Ischemic Stroke Patients]

The treatment of acute ischemic stroke usually involves argatroban administration by continuous infusion for 2 d and by intravenous infusion twice a day for 5 d after that. However, the appropriate dose of argatroban to be administered is not clear. Therefore, no studies have been reported a comparison of intravenous and continuous argatroban infusion after day 3 for acute ischemic stroke patients. We aimed to identify the connection between differences in argatroban administration and worsening of symptoms after day 3 in ischemic stroke patients. We retrospectively evaluated the data of 107 ischemic stroke patients who received treatment with argatroban. The study endpoint was defined as the worsening of symptoms from days 3 to 7. Logistic regression analysis was used to determine the risk factors that were significantly associated with worsening of symptoms. Patients were administered argatroban, with rates of 72.0%, and 28.0% for continuous, and intravenous infusion, respectively. A total of 10 (9.3%) patients experienced worsening of symptoms. In the single logistic regression analysis, carotid stenosis [non-adjusted odds ratio (OR) 5.775, 95% confidence interval (CI) 1.486-22.442, p=0.011] was only significantly associated with worsening of symptoms. Worsening of symptoms was not related to either intravenous or continuous infusion group (16.7% vs. 6.5%, p=0.104). Bleeding was also not associated with either group (6.7% vs. 3.9%, p=0.618). We suggest that the differences in the mode of argatroban administration were not related to the worsening of symptoms in ischemic stroke patients. We also found that safety was equivalent regardless of the administration route.

Effect of Argatroban Combined With Dual Antiplatelet Therapy on Early Neurological Deterioration in Acute Minor Posterior Circulation Ischemic Stroke

There is a lack of studies on anticoagulant plus antiplatelet therapy for acute ischemic stroke. The present study made a pilot effort to investigate the efficacy and safety of argatroban plus dual antiplatelet therapy (DAPT) in patients with acute posterior circulation ischemic stroke (PCIS). We retrospectively collected patients diagnosed with acute PCIS according to inclusion/exclusion criteria. According to treatment drugs, patients were divided into an argatroban plus DAPT group and a DAPT group. The primary efficacy end point was the proportion of early neurological deterioration (END). The primary safety outcome was symptomatic intracranial hemorrhage. All outcomes were compared between the 2 groups before and after propensity score matching (PSM). A total of 502 patients were enrolled in the study, including 35 patients with argatroban plus DAPT and 467 patients with DAPT. There was a higher National Institutes of Health Stroke Scale (NIHSS) score in the argatroban plus DAPT group than the DAPT group before PSM (3 vs 2, P = .017). Compared with the DAPT group, the argatroban plus DAPT group had no END (before PSM: 0% vs 6.2%, P = .250; after PSM: 0% vs 5.9%, P = .298). Argatroban plus DAPT yielded a significant decrease in the NIHSS score from baseline to 7 days after hospitalization, compared with that of the DAPT group before PSM (P = .032), but not after PSM (P = .369). No symptomatic intracranial hemorrhage was found in any patient. A short-term combination of argatroban with DAPT appears safe in acute minor PCIS.

Direct Thrombin Inhibitors as an Alternative to Heparin During Catheter Ablation: A Multicenter Experience

OBJECTIVES

The goal of this study was to report a multicenter series of left-sided catheter ablations performed by using intravenous direct thrombin inhibitors (DTIs) as an alternative to heparin.

BACKGROUND

Amidst a looming worldwide shortage of heparin, there are insufficient data to guide nonheparin-based peri-procedural anticoagulation in patients undergoing catheter ablation.

METHODS

This study reviewed all catheter ablations at 6 institutions between 2006 and 2019 to assess the safety and efficacy of DTIs for left-sided radiofrequency catheter ablation of atrial fibrillation and ventricular tachycardia.

RESULTS

In total, 53 patients (age 63.0 ± 9.3 years, 68% male, CHA₂DS₂-VASc [congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, stroke/transient ischemic attack, vascular disease, age 65 to 74 years, sex category] score 2.8 ± 1.6, left ventricular ejection fraction 46 ± 15%) underwent ablation with DTIs (75% bivalirudin, 25% argatroban) due to heparin contraindication(s) (72% heparin-induced thrombocytopenia, 21% heparin allergy, 4% protamine reaction, and 4% religious reasons). The patient's usual oral anticoagulant was continued without interruption in 69%. Procedures were performed for atrial fibrillation (64%) or ventricular tachycardia/premature ventricular contractions (36%). Transseptal puncture was undertaken in 81%, and a contact force-sensing catheter was used in 70%. Vascular ultrasound was used in 71%, and femoral arterial access was gained in 36%. A bolus followed by infusion was used in all but 4 cases, and activated clotting time was monitored peri-procedurally in 72%, with 32% receiving additional boluses. Procedure duration was 216 ± 116 min, and ablation time was 51 ± 22 min. No major bleeding or embolic complications were observed. Four patients had minor self-limiting bleeding complications, including a small pericardial effusion (<1 cm), a small groin hematoma, and hematuria.

CONCLUSIONS

In this multicenter series, intravenous DTIs were safely used as an alternative to heparin for left-sided catheter ablation.

New Hemostatic Agents: Perioperative Anesthetic Considerations

AIM

Pharmacologic agents with procoagulant effects and antidotes against antithrombotic drugs play an important role in the prevention and management of perioperative coagulopathic bleeding. The aim of this narrative review is knowledge transfer from new and renewed hemostatic agents to anesthesiologists and other physicians involved in perioperative medicine.

METHODS

The literature search was performed on PubMed and the Summaries of Product Characteristics of 6 pharmacologic agents of interest: fibrinogen concentrate, vonicog alfa, susoctocog alfa, idarucizumab, andexanet alfa, and argatroban.

RESULTS AND DISCUSSION

This review highlights renewed interest in fibrinogen concentrate, an old prohemostatic drug, in correcting hypofibrinogenemia which is a leading pathomechanism of perioperative bleeding. This review describes clinically relevant aspects for brand new recombinant prohemostatic drugs for their use in critical clinical situations: vonicog alfa for the prevention and correction of bleeding in von Willebrand syndrome, and susoctocog alfa in acquired hemophilia A. Clinical experience and increasing evidence broadened the field of applications of the old antithrombotic drug argatroban to heparin resistance. New antidotes against new antithrombotic agents revolutionized the safety of chronic antithrombotic therapy in the emergency situations of acute and trauma surgery. Information on dosing and handling of new hemostatic drugs is summarized.

CONCLUSION

New and potent hemostatic agents exist for perioperative use and may enrich the armamentarium of anesthesiologists. Implementation into clinical practice requires their availability and user knowledge. Sustainability of these new drugs depends on post-licensing research, cost-effectiveness, and clinical experience.

Successful endovascular therapy for cerebral venous sinus thrombosis accompanied by heparin-induced thrombocytopenia

INTRODUCTION

Heparin-induced thrombocytopenia (HIT) is an immune-mediated complication of heparin exposure. A limited number of studies have reported cerebral venous sinus thrombosis accompanied by heparin-induced thrombocytopenia. Here, we present a case of successful endovascular therapy (EVT) without periprocedural heparinization in this situation.

CASE PRESENTATION

A 47-year-old woman taking an oral contraceptive was admitted to our hospital with severe headache to be diagnosed as cerebral venous sinus thrombosis. Initially, she got improved by medical treatment with intravenous unfractionated heparin. However, she rapidly developed disturbance of consciousness and right hemiplegia due to cerebral venous sinus thrombosis accompanied by heparin-induced thrombocytopenia on the 14th hospital day. She underwent emergent EVT by immediate conversion of anticoagulation from heparin to argatroban. Despite a large clot burden, sufficient recanalization and anterograde venous drainage were re-established by combined EVT including aspiration, balloon sinoplasty, and local thrombolysis with urokinase infusion. She got improved immediately after the intervention and discharged home without any neurological sequelae after two months.

CONCLUSION

This unique case of cerebral venous sinus thrombosis worsened by occurrence of heparin-induced thrombocytopenia during the treatment finally resulted in excellent outcome highlights effectiveness of emergent endovascular intervention for critical cerebral venous sinus thrombosis resistant to initial medical treatment and of immediate establishment of effective anticoagulant strategy for both of heparin-induced thrombocytopenia and cerebral venous sinus thrombosis. Neuroendovascular therapy for cerebral venous sinus thrombosis using alternative argatroban to heparin for periprocedural anticoagulation might be safe and feasible.

Clinical study of argatroban for preventing vascular thrombosis in the early period after pediatric living-related donor liver transplantation

OBJECTIVE

To evaluate the effect of heparin and argatroban on coagulation function and vascular thrombosis in the early period after pediatric LRDLT.

METHOD

Eighty-four congenital biliary atresia pediatric patients who had undergone LRDLT were studied. Patients were divided into two groups according to the method of anticoagulation (heparin or argatroban). AT-Ⅲ activity, APTT, and INR of the two groups were measured in the first 5 days after LRDLT. Vascular thrombosis was investigated by Doppler ultrasound daily.

RESULTS

There were no significant differences in gender, age, weight, graft-recipient weight ratio, and Kasai procedure between the two groups. The AT-Ⅲ activity of the two groups was low and increased gradually after surgery, with no significant difference between the two groups. There was no significant difference of APTT between the two groups immediately after and in the first day after surgery. After anticoagulation treatment, a significant difference in APTT between the two groups was observed. The incidences of vascular thrombosis were 4.76% (3/63) and 0% (0/21) in the heparin and argatroban groups, respectively, with no significant difference between the two groups. During the treatment, no serious complications such as active hemorrhage or drug allergy were observed in the two groups.

CONCLUSION

Argatroban is a direct anticoagulant, which is independent of AT-Ⅲ activity. Argatroban might be an alternative to heparin in uncomplicated LRDLT with recovered hepatic and coagulation function.

Early Identification of Argatroban Resistance and the Consideration of Factor VIII

BACKGROUND

Argatroban, a synthetic, parenteral, nonheparin anticoagulant, is a direct thrombin inhibitor indicated for the prophylaxis or treatment of venous thromboembolism (VTE) in patients with heparin-induced thrombocytopenia with thrombosis (HITT) and for use during percutaneous coronary intervention (PCI) in patients who have or are at risk for developing HITT. Although heparin resistance occurs in approximately 0.5% to 5% of heparin-treated patients and is well documented in the literature, argatroban resistance is limited to a single case report. The objective of this case is to describe a case in which argatroban resistance was suspected in a patient with critical limb ischemia.

METHODS

This is a case report of a single patient.

RESULTS

A 68-year-old female admitted for critical limb ischemia requiring vascular intervention was treated for presumed HITT with argatroban. A therapeutic activated partial thromboplastin time (aPTT) was not attained (31 seconds) despite multiple uptitrations of the dose to 2.8 μg/kg/min (adjusted based on the institutional protocol and with consideration of organ dysfunction). A coagulopathy workup revealed a high level of factor VIII (265%).

CONCLUSION

This case supports early assessment of factor VIII levels and the consideration of argatroban resistance and in patients who have a subtherapeutic aPTT, despite multiple increases in dose with an elevated factor VIII level. Early identification should prompt the use of an alternative anticoagulant to ensure efficacy.

Massive Left Atrial Thrombus in Two Patients with Heparin-Induced Thrombocytopenia Type II after Cardiac Surgery

Heparin-induced thrombocytopenia type II (HIT type II) can have devastating consequences in cardiac surgical patients. We report two cases of massive left atrial thrombus after mitral valve replacement and endocardial cryoablation in patients with HIT type II.

Use of an argatroban-based purge solution in a percutaneous ventricular assist device

PURPOSE

The use of an argatroban-based percutaneous ventricular assist device (pVAD) purge solution in a patient with suspected heparin-induced thrombocytopenia (HIT) is described.

SUMMARY

A 70-year-old woman in cardiogenic shock was admitted to a coronary care unit after being discovered unresponsive at home. A transthoracic echocardiogram revealed a low ejection fraction and findings consistent with takotsubo cardiomyopathy. Administration of multiple inotropes and vasopressors was initially required for hemodynamic support. The patient was implanted with an Impella pVAD (Abiomed, Inc., Danvers, MA) using a heparin-based purge solution; an i.v. heparin infusion was initiated for supplemental systemic anticoagulation. Over the next 24 hours, the patient's platelet count decreased from 168,000 to 37,000 cells/μL. Given a differential diagnosis that included HIT, the patient was transitioned to an argatroban-based purge solution. Due to prolonged activated partial thromboplastin times, a systemic argatroban infusion was not initiated, and the patient remained fully anticoagulated throughout pVAD support with only the argatroban-based purge solution. An HIT antibody test was negative. On hospitalization day 9 (day 6 of pVAD support with argatroban use), the patient became hemodynamically stable and was weaned off pVAD support. Three days later, the platelet count had recovered to 117,000 cells/μL (from a nadir of 21,000 cells/μL). During pVAD support, the patient developed hemolytic anemia with minimal bleeding complications.

CONCLUSION

Argatroban was used as a purge solution anticoagulant in a patient with an Impella pVAD and found to be a safe and effective alternative to heparin.

A hypercoagulable state leading to venous limb gangrene associated with occult lung adenocarcinoma

We report a case of lung adenocarcinoma-associated hypercoagulability leading to venous limb gangrene, managed successfully with argatroban and then dabigatran. Use of idarucizumab permitted diagnostic investigations, leading to targeted antineoplastic therapy with crizotinib, surgical resection with curative intent, and continued survival over 2 years after the index event.

A 24-hour perioperative case study on argatroban use for left ventricle assist device insertion during cardiopulmonary bypass and veno-arterial extracorporeal membrane oxygenation

A 44-year-old male with ongoing chest pain and left ventricular ejection fraction <20% was transferred from a peripheral hospital with intra-aortic balloon pump placement following a non-ST-elevation myocardial infarction (STEMI). The patient underwent emergent multi-vessel coronary artery bypass grafting requiring veno-arterial (VA) extracorporeal membrane oxygenation (ECMO) on post-operative day (POD)#9 secondary to cardiogenic shock with biventricular failure. Due to clot formation, an oxygenator change-out was necessary shortly after initiation. Following a positive heparin-induced thrombocytopenia (HIT) assay, a total circuit exchange was required to eliminate all heparin coating and argatroban was deemed the anticoagulant of choice due to acute kidney injury. On POD#24, the decision was made to implant a left ventricle assist device (LVAD) as a bridge to heart transplantation. There was difficulty achieving an activated clotting time (ACT) >400 s: multiple argatroban bolus doses were required, along with accelerated up-titration of infusion dosing. Despite maintaining an ACT >484 s, clot formation was observed in the cardiotomy reservoir prior to separation. Subsequently, the patient developed severe disseminated intravascular coagulopathy, with both intra-cardiac and intravascular thrombi, requiring massive transfusion and continuous cell saving due to severe hemorrhage post cardiopulmonary bypass (CPB). The patient received a total of 105 units of plasma, 74 units of packed red cells, 19 units of platelets, 13 bottles of 5% albumin, 6 units of cryoprecipitate and 2 doses of factor VIIa intraoperatively over the course of 24 hours. A total of 19.7 L of washed red blood cells were returned to the patient from the cell saver. With the LVAD in place, the patient developed transfusion-related acute lung injury and acute respiratory distress syndrome with right ventricular dysfunction requiring VA ECMO once again. On POD#30, ECMO was discontinued and the patient was discharged from the intensive care unit (ICU) on POD 66. After a very complex post-operative stay with numerous surgeries and extensive rehabilitation, the patient was discharged home with the LVAD on POD#112.

Use of argatroban for extracorporeal life support in patients with nonheparin-induced thrombocytopenia: Analysis of 10 consecutive patients

Unfractionated heparin (UFH) is currently the standard anticoagulant used in extracorporeal life support (ECLS). However, severe thrombocytopenia occurs frequently during ECLS use and it may be difficult to determine whether this represents heparin-induced thrombocytopenia (HIT) or not. In this case, UFH cannot be continued. Because a confirmatory laboratory test requires time, argatroban is empirically used if HIT is suspected. However, many patients are not found to have HIT. In non-HIT patients, the effectiveness and safety of argatroban are unclear. Thus, we investigated whether argatroban was safe and useful in patients who were suspected of having HIT and were started on argatroban, but were ultimately found to have non-HIT.We retrospectively reviewed all patients on ECLS who received the anticoagulant argatroban as an alternative to UFH between January 2014 and July 2015. The pretest clinical score (4Ts) was calculated, and a score greater than 4 was considered an indication for argatroban. The target-activated clotting time or activated partial thromboplastin time was 1.5 times the patient's upper normal value. Of 191 patients on ECLS during the study period, 10 (5.2%) were treated with argatroban infusion.No patients were found to have antiplatelet factor 4/heparin antibodies. The average maintenance dose of argatroban was 0.1 μg/kg/min. Platelet counts increased significantly following argatroban administration (P = .02). There were no anticoagulation-related complications such as bleeding or thrombosis.Our results suggest that argatroban is a safe alternative to UFH for patients with non-HIT on ECLS. Argatroban may have a more significant platelet-preserving effect than UFH, regardless of whether HIT is present.

Safety and Feasibility of Argatroban, Recombinant Tissue Plasminogen Activator, and Intra-Arterial Therapy in Stroke (ARTSS-IA Study)

BACKGROUND

A randomized trial of concurrent recombinant tissue-type plasminogen activator (r-tPA) + thrombin-inhibition with Argatroban in stroke patients recently demonstrated safety and signal of efficacy compared to r-tPA alone, but patients having endovascular therapy (EVT) were excluded. The current study intended to study feasibility and safety of concurrent r-tPA and Argatroban in patients undergoing EVT.

METHODS

We conducted a single-arm, feasibility, and safety study of patients that received standard-dose r-tPA, had intracranial large vessel occlusions, and underwent EVT within 6 hours of stroke onset. During r-tPA, a 100 μg/kg Argatroban bolus, followed by 12-hour infusion, targeted an activated Partial Thromboplastin Time (aPTT) 2.25 timesbaseline. Feasibility was defined as ability to combine treatments without EVT time-metric delays, compared to cotemporaneous r-tPA + EVT treatments. Safety was incidence of symptomatic intracerebral hemorrhage (sICH), systemic hemorrhage, or EVT complications.

RESULTS

All preplanned 10 patients were enrolled. Arterial occlusions were middle cerebral artery (n = 8), internal carotid artery (n = 1), and posterior cerebral artery (n = 1). All received Argatroban before EVT and completed infusions. There were no delays in time-metrics compared to nonstudy patients during the same period. Nine patients achieved excellent angiographic reperfusion (Thrombolysis In Cerebral Ischemia [TICI] ≥2b); with 7 complete (TICI = 3). There were no sICH, systemic hemorrhage, or EVT complications. At 90 days, 6 (60%) patients had a modified Rankin Scale of 0-2 and none died.

CONCLUSIONS

In patients treated with r-tPA and EVT, concomitant Argatroban is feasible, does not delay EVT provision, produces high rates of recanalization, is probably safe, and warrants further study.

Evaluation of anticoagulant agents for the treatment of human metapneumovirus infection in mice

Thrombin has been demonstrated to be involved in several viral diseases including human metapneumovirus (hMPV) infections. We previously showed that immediate administration of thrombin inhibitor argatroban post-infection protected mice against hMPV disease. This current work aims at determining whether warfarin and heparin, two other anticoagulants inhibiting thrombin formation and activities, may also be used for treatment against hMPV in vivo. We found that immediate injections of argatroban, warfarin or heparin after virus challenge protected mice against hMPV infection, as evidenced by decreased or no mortality, less weight loss, reduced viral load and attenuated inflammation. However, delayed treatments starting 1 day post-infection with argatroban or warfarin almost did not impact the survival whereas delayed treatment with heparin induced an increased mortality during infection. Moreover, these treatments also did not reduce weight loss, viral replication and inflammation. In agreement with these results, thrombin generation was decreased upon immediate anticoagulant treatments but was unaltered upon delayed treatments. Thus, thrombin generation occurs at the onset of hMPV infection and thrombin inhibition may be only useful for the treatment of this disease when initiated in the early stage. In this case, heparin is not recommended because of its reduced efficacy on mortality in infected mice whereas argatroban and warfarin appear as safe and effective drugs for the treatment of hMPV disease. The antiviral and anti-inflammatory effects of argatroban occur via thrombin-dependent pathways whereas the mechanisms by which warfarin exerts its beneficial effects against hMPV infection were not elucidated and need to be further studied.

Upper Limb Phlegmasia Cerulea Dolens Secondary to Heparin-induced Thrombocytopenia Leading to Gangrene

We present a case of a dialysis-dependent end-stage renal disease patient who originally presented with sepsis and later developed heparin-induced thrombocytopenia-related upper extremity deep venous thrombosis that rapidly progressed to phlegmasia. Argatroban, a direct thrombin inhibitor, was initiated without delay. Argatroban restored the venous patency completely but did not reverse his two gangrenous fingers. The patient finally underwent digital amputation. The management of this uncommon, but life-threatening, situation of upper limb phlegmasia cerulea dolens secondary to heparin-induced thrombocytopenia leading to gangrene is discussed in this case report.

Argatroban administration as therapy for thrombosis in patients with continuous-flow ventricular assist devices

Background

Device thrombosis is one of the main complications in left ventricular assist devices (LVAD) therapy and remains a challenging issue. Data on device thrombosis management, especially on the application of direct thrombin inhibitors such as argatroban, is limited and a consensus on thrombosis management has not yet been established.

Methods

In this study we analysed retrospective clinical data obtained from 26 patients on VAD therapy who received argatroban for suspected VAD thrombosis, between April, 2012 and February, 2017.

Results

Thirteen patients (50%) showed resolution of thrombus after argatroban therapy. Eight of 26 patients (30.8%) were free of thrombotic events 90 days after discharge. Argatroban therapy was unsuccessful in 13 patients of the study cohort, leading to subsequent VAD-exchange. Six of 13 patients with first VAD-exchange had no thrombotic events 90 days after discharge. Six patients (23.1%) suffered from bleeding, especially gastrointestinal bleeding. No hemorrhagic strokes were observed. Three patients (11.5%) did not survive the follow-up period.

Conclusions

Argatroban appears to be an alternative to other pharmacological treatment options in VAD thrombosis. Efficacy and safety characteristics are acceptable, but further investigation on larger populations is necessary.

Acute coagulation disorder in a critically ill patient - A case report

A 79-year-old critically ill woman presented with remarkable prolongation of activated partial thromboplastin time and thrombin time combined with high levels of anti-factor IIa activity 26 days after coronary artery bypass grafting. Coagulation disorder was associated with severe bleeding. Cause of coagulopathy was accidental administration of argatroban in an unknown dosage. Clearance of argatroban was significantly prolonged because of a liver function disorder related to septic multiorgan failure. Argatroban reversal was performed with prothrombin complex concentrate.

Anticoagulation Management during First Five Days of Infant-Pediatric Extracorporeal Life Support

Anticoagulation during infant-pediatric extracorporeal life support (ECLS) has been a topic of study for many years, but management of anticoagulation is still only partially understood. Adequate anticoagulation during ECLS is imperative for successful outcomes and understanding the individual variables that play part is crucial for properly implementing anticoagulation management strategies. The purpose of our study was to compare the relationships between the variables of activated partial thromboplastin time (aPTT), activated clotting time, international normalized ratio, bleeding, thrombus formation, kaolin + heparinase thromboelastograph alpha angle, kaolin thromboelastograph reaction time (KTEG R-time), heparin dose rates (HDR), antithrombin (AT), anti-Xa, bivalirudin dose rate, argatroban dose rate, interventions, and transfusions. We hypothesized that the relationship between measures of anticoagulation would be influenced by the AT levels, and a therapeutic aPTT (60-80 seconds) could be achieved by increasing, or maintaining, the overall AT above a specific threshold for infant-pediatric patients on ECLS. Thirty-five infant-pediatric patients underwent ECLS between January 2013 and January 2016. The median age was 39 days with an average weight of 3.9 ± 4.3 kg. ECLS parameters collected at least every 24 hours for the first five ECLS days. Parameters recorded by retrospective chart review were analyzed using linear regression and receiver operator characteristic (ROC) analysis. We were unable to report a significant correlation between optimal aPTT and HDR at various AT levels. However, ROC analysis suggested that to maintain an aPTT above 60 seconds, an AT threshold of 42% or higher was observed when the HDR was >12 U/kg/h ROC analysis also determined that no thrombus was associated with an aPTT >64 seconds and decreased bleeding was associated with a KTEG R-time below 30 minutes. Based on these findings, we report multiple correlations that may help develop future standardized infant-pediatric ECLS anticoagulation protocols.

The Role of Apixaban in the Treatment of Heparin-Induced Thrombocytopenia

Heparin-induced thrombocytopenia (HIT) can present as arterial and venous thrombosis in adults who are treated with heparin. We present a case of a patient who developed HIT when she was treated for deep venous thrombosis (DVT) and pulmonary embolism with heparin. During the treatment with heparin and while being transitioned to warfarin, she developed arterial thrombosis. A work-up for HIT was sent, and it was positive. She was started on the argatroban drip and her platelet counts stabilized. Since her platelet counts remained stable and were not increasing for three weeks, we decided to transition the patient to an oral anticoagulant. She was started on apixaban, a novel oral anticoagulant (NOAC), and her platelet counts remained stable. Therefore, through this case, we highlight the importance of platelet counts remaining stable when a patient with HIT is treated with apixaban.

Heparin-Induced Thrombocytopenia: A Comprehensive Clinical Review

Heparin-induced thrombocytopenia is a profoundly dangerous, potentially lethal, immunologically mediated adverse drug reaction to unfractionated heparin or, less commonly, to low-molecular weight heparin. In this comprehensive review, the authors highlight heparin-induced thrombocytopenia's risk factors, clinical presentation, pathophysiology, diagnostic principles, and treatment. The authors place special emphasis on the management of patients requiring procedures using cardiopulmonary bypass or interventions in the catheterization laboratory. Clinical vigilance of this disease process is important to ensure its recognition, diagnosis, and treatment. Misdiagnosis of the syndrome, as well as misunderstanding of the disease process, continues to contribute to its morbidity and mortality.

Randomized, Multicenter Trial of ARTSS-2 (Argatroban With Recombinant Tissue Plasminogen Activator for Acute Stroke)

BACKGROUND AND PURPOSE

We conducted a randomized exploratory study to assess safety and the probability of a favorable outcome with adjunctive argatroban, a direct thrombin-inhibitor, administered to recombinant tissue-type plasminogen activator (r-tPA)-treated ischemic stroke patients.

METHODS

Patients treated with standard-dose r-tPA, not receiving endovascular therapy, were randomized to receive no argatroban or argatroban (100 μg/kg bolus) followed by infusion of either 1 (low dose) or 3 μg/kg per minute (high dose) for 48 hours. Safety was incidence of symptomatic intracerebral hemorrhage. Probability of clinical benefit (modified Rankin Scale score 0-1 at 90 days) was estimated using a conservative Bayesian Poisson model (neutral prior probability centered at relative risk, 1.0 and 95% prior intervals, 0.33-3.0).

RESULTS

Ninety patients were randomized: 29 to r-tPA alone, 30 to r-tPA+low-dose argatroban, and 31 to r-tPA+high-dose argatroban. Rates of symptomatic intracerebral hemorrhage were similar among control, low-dose, and high-dose arms: 3/29 (10%), 4/30 (13%), and 2/31 (7%), respectively. At 90 days, 6 (21%) r-tPA alone, 9 (30%) low-dose, and 10 (32%) high-dose patients were with modified Rankin Scale score 0 to 1. The relative risks (95% credible interval) for modified Rankin Scale score 0 to 1 with low, high, and either low or high dose argatroban were 1.17 (0.57-2.37), 1.27 (0.63-2.53), and 1.34 (0.68-2.76), respectively. The probability that adjunctive argatroban was superior to r-tPA alone was 67%, 74%, and 79% for low, high, and low or high dose, respectively.

CONCLUSIONS

In patients treated with r-tPA, adjunctive argatroban was not associated with increased risk of symptomatic intracerebral hemorrhage and provides evidence that a definitive effectiveness trial is indicated.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique Identifier: NCT01464788.

Local Intraluminal Irrigation With Argatroban During Free Flap Repair in a Patient With Heparin-Induced Thrombocytopenia

OBJECTIVE

This study describes a case of a successful free flap repair using argatroban for local intraluminal irrigation as a substitute to heparin in a patient with heparin-induced thrombocytopenia.

METHODS

Case report and review of literature.

RESULTS

The patient had an uneventful postoperative course, and the free flap survived without complications.

CONCLUSIONS

The use of argatroban during microvascular surgery is likely to be safe and simple and may be effective in preventing micro-thrombotic complications during microvascular surgery, and it should be considered as an alternative to heparinized saline for local intraluminal irrigation.