Vaccine-induced immune thrombotic thrombocytopenia (VITT) has been described following adenovirus vector-based COVID-19 vaccines. This condition is associated with important morbidity and mortality following thrombosis related complications. Diagnosis is confirmed based on results of platelet factor 4 ELISA detecting anti-PF4 antibodies and of platelet-activation assay. Initial treatment strategy has been established but long-term management and follow up remain unclear. Most platelet-activation tests become negative after 12 weeks. We describe a case of VITT which can now be characterized as long VITT. The patient initially had a lower limb ischemia, pulmonary embolism and cerebral vein thrombosis. He was treated with prednisone, intravenous immunoglobulin, argatroban and had a lower limb revascularization surgery. Rivaroxaban was then initiated for the acute treatment and continued for the secondary prevention of recurrent events. The patient still demonstrates positive platelet-activation tests and thrombocytopenia after more than 18 months of follow-up. No recurrent thrombosis or bleeding event have occurred. He is not known for any relevant past medical history other than alcohol consumption and slight thrombocytopenia (130 × 109/L since 2015). It is unclear if the ongoing and more important thrombocytopenia could be explained by the persistent platelet-activating anti-PF4 antibodies or the patient's habits. Managing long VITT is challenging considering uncertainty regarding risks and benefits of long-term anticoagulation and potential needs of additional treatment. Additional data is needed to offer optimal long-term management for this patient population. We suggest that long VITT diagnosis definition might include the persistence within patient serum/plasma of anti-PF4 platelet-activating antibodies with clinical manifestations (e.g., thrombocytopenia) for more than 3 months.

Transmembrane protease serine 2 (TMPRSS2) has been identified as a critical key for the entry of coronaviruses into human cells by cleaving and activating the spike protein of SARS-CoV-2. To block the TMPRSS2 function, 18 approved drugs, containing the guanidine group were tested against TMPRSS2's ectodomain (7MEQ). Among these drugs, Famotidine, Argatroban, Guanadrel and Guanethidine strongly binds with TMPRSS2 S1 pocket with estimated Fullfitness energies of -1847.12, -1630.87, -1605.81 and -1600.52 kcal/mol, respectively. A significant number of non-covalent interactions such as hydrogen bonding, hydrophobic and electrostatic interactions were detected in protein-ligand complexes. In addition, the ADMET analysis revealed a perfect concurrence with the aptitude of these drugs to be developed as an anti-SARS-CoV-2 therapeutics. Further, MD simulation and binding free energy calculations were performed to evaluate the dynamic behavior and stability of protein-ligand complexes. The results obtained herein highlight the enhanced stability and good binding affinities of the Argatroban and Famotidine towards the target protein, hence might act as new scaffolds for TMPRSS2 inhibition. Communicated by Ramaswamy H. Sarma.

Introduction: Cerebral venous thrombosis (CVT) is a life-threatening neurological condition. There is limited evidence for the use of direct oral anticoagulants (DOAC) for long-term anticoagulation in this patient population. We report a case series of patients treated with apixaban and their clinical course. Methods: This was a retrospective cohort study. Patients diagnosed with CVT in a defined time period at our institution were screened for long-term anticoagulation and patients who were treated with apixaban were included in this study. Results: A total of nine patients were included in this study. The mean age was 36 years and 56% of the patients included were women. All received initial anticoagulation with unfractionated heparin (UFH) infusion for at least twenty-four hours, except for one patient who had anti-thrombin III deficiency and was treated with argatroban infusion. For long-term anticoagulation, 56% of patients received apixaban 10 mg twice daily for the first five to seven days followed by 5 mg twice daily, while the remaining 44% were transitioned from IV anticoagulation to apixaban 5 mg twice daily. There were no adverse events reported, except for one patient who developed anemia after 7 months of treatment and required a blood transfusion. Complete recanalization was achieved in 78% while 22% had partial recanalization. Follow-up time ranged from six to twenty-three months. Conclusion: The use of apixaban for long-term anticoagulation in CVT resulted in recanalization in all of the patients in this case series without any major side effects. This case series adds to the emerging studies demonstrating the utility of apixaban for CVT.

We report a case of a 77-year-old woman with massive pulmonary embolism associated with heparin-induced thrombocytopenia. Before developing a pulmonary embolism, the patient underwent gastrectomy due to gastric cancer and received subcutaneous heparin calcium for deep venous thrombosis prophylaxis for 5 d. Then, thrombectomy with cardiopulmonary bypass using full heparinization was successfully performed. The patient was definitively diagnosed with this condition postoperatively, based on elevated serum antibody levels, in addition to pre- and postoperative thrombocytopenia and thrombosis. Intravenous heparin therapy was switched to argatroban. Although it is uncommon, clinicians should consider this condition in patients with a history of heparin exposure.

Background: Heparin-induced thrombocytopenia (HIT) is a serious, immune-mediated adverse drug reaction to unfractionated heparin (UFH) affecting also patients undergoing venoarterial extracorporeal membrane oxygenation (VA-ECMO). Although the association between VA-ECMO support and the development of thrombocytopenia has long been known and discussed, HIT as one underlying cause is still insufficiently understood. Therefore, the purpose of this study was to further investigate the epidemiology, mortality, diagnosis, and clinical management of HIT occurring in VA-ECMO patients treated with UFH. Methods: We conducted a retrospective single-center study including adult patients (≥18 years) with VA-ECMO support in the cardiac intensive care unit (ICU) of the University Hospital of Munich (LMU) between January 2013 and May 2022, excluding patients with a known history of HIT upon admission. Differences in baseline characteristics and clinical outcome between excluded HIT (positive anti-platelet factor 4 (PF4)/heparin antibody test but negative functional assay) and confirmed HIT (positive anti-PF4/heparin antibody test and positive functional assay) VA-ECMO patients as well as diagnosis and clinical management of HIT were analysed. Results: Among the 373 patients included, anti-PF4/heparin antibodies were detected in 53/373 (14.2%) patients. Functional HIT testing confirmed HIT in 13 cases (3.5%) and excluded HIT in 40 cases (10.7%), corresponding to a prevalence of confirmed HIT of 13/373 (3.5%) [1.6, 5.3] and a positive predictive value (PPV) of 24.5% for the antibody screening test. The platelet course including platelet recovery following argatroban initiation was similar between all groups. One-month mortality in patients with excluded HIT was 14/40 (35%) and 3-month mortality 17/40 (43%), compared to 5/13 (38%) (p > 0.999), and 6/13 (46%) (p > 0.999) in patients with confirmed HIT. Neurological outcome in both groups measured by the cerebral performance category of survivors on hospital discharge was similar, as well as adverse events during VA-ECMO therapy. Conclusions: With a prevalence of 3.5%, HIT is a non-frequent complication in patients on VA-ECMO and was not associated with a higher mortality rate. HIT was ultimately excluded by functional essay in 75% of VA-ECMO patients with clinical suspicion of HIT and positive anti-PF4/heparin antibody test. Argatroban seems to be an appropriate and safe therapeutic option for confirmed HIT-positive patients on VA-ECMO support.

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.

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.

Due to thrombosis and intimal hyperplasia, small-diameter vascular grafts have poor long-term patency. A combination strategy based on nitric oxide (NO) and anticoagulants has the potential to address those issues. In this study, poly(ethylene terephthalate) (PET) mats were prepared by electrospinning and coated with tannic acid (TA)/copper ion complexes. The chelated copper ions endowed the mats with sustained NO generation by catalytic decomposition of endogenous S-nitrosothiol. Subsequently, zwitterionic carboxybetaine acrylate (CBA) and argatroban (AG) were immobilized on the mats. The introduced AG and CBA had synergistic effects on the improvement of blood compatibility, resulting in reduced platelet adhesion and prolonged blood clotting time. The biocomposite mats selectively promoted the proliferation and migration of human umbilical vein endothelial cells while inhibiting the proliferation and migration of human umbilical arterial smooth muscle cells under physiological conditions. In addition, the prepared mats exhibited antibacterial activity against Escherichia coli and Staphylococcus aureus. Collectively, the prepared mats hold great promise as artificial small-diameter vascular grafts.

Non-alcoholic fatty liver disease represents the most common liver disease worldwide and the prevailing cause of liver-related morbidity and mortality. It encompasses a broad clinical spectrum ranging from nonalcoholic fatty liver to nonalcoholic steatohepatitis (NASH), advanced fibrosis, cirrhosis, and finally hepatocellular carcinoma. There have been many studies about the underlying mechanisms of NASH progression, fueling a solid therapeutic pipeline across a variety of potential targets to resolve steatohepatitis or fibrosis. Unfortunately, no therapeutic agent has been approved so far for NASH. In an interesting study, Wei et al. highlighted the role of MRG15 as a targetable epigenetic remodeller in the rhythmic regulation of hepatic lipid metabolism. Remarkably, a recent study from the same group uncovered a chromatin-binding independent working mechanism of MRG15 in regulating the progression from early liver steatosis to the advanced NASH stage with fibrosis and inflammation. Collectively, these studies have shown that MRG15 constitutes a key factor during different stages of NAFLD development. Nuclear MRG15 is recruited to promoter regions of liver lipogenesis genes by LRH-1, where it activates the rhythmic expression of lipid synthesis genes, leading to liver steatosis; while in mitochondria, MRG15 accelerates TUFM degradation, resulting in the aggravation of inflammation and fibrosis, and NASH progression. Blocking of MRG15 by CRISPR targeting or by the FDA-approved drug argatroban, which is an antagonist to MRG15, may attenuate liver steatosis. Further studies regarding the functional aspects of MRG15 in different cell types and its regulatory signals will shed light on the intriguing functions of MRG15 in lipid metabolism and tissue fibrogenesis.

Infants with congenital diaphragmatic hernia (CDH) may require cardiopulmonary bypass and systemic anticoagulation. Expeditious lung growth while on bypass is essential for survival. Previously, we demonstrated that heparin impairs lung growth and function in a murine model of compensatory lung growth (CLG). We investigated the effects of the direct thrombin inhibitors (DTIs) bivalirudin and argatroban. In vitro assays of lung endothelial cell proliferation and apoptosis were performed. C57BL/6 J mice underwent left pneumonectomy and subcutaneous implantation of osmotic pumps. Pumps were pre-loaded with normal saline (control), bivalirudin, argatroban, or heparin and outcomes were assessed on postoperative day 8. Heparin administration inhibited endothelial cell proliferation in vitro and significantly decreased lung volume in vivo, while bivalirudin and argatroban preserved lung growth. These findings correlated with changes in alveolarization on morphometric analysis. Treadmill exercise tolerance testing demonstrated impaired exercise performance in heparinized mice; bivalirudin/argatroban did not affect exercise tolerance. On lung protein analysis, heparin decreased angiogenic signaling which was not impacted by bivalirudin or argatroban. Together, this data supports the use of DTIs as alternatives to heparin for systemic anticoagulation in CDH patients on bypass. Based on this work, clinical studies on the impact of heparin and DTIs on CDH outcomes are warranted.

Intraprocedural stent thrombosis is a rare but serious complication of reperfusion therapy for acute coronary syndrome. There is currently no consensus on the intraprocedural management of intraprocedural stent thrombosis. It is difficult to attain thrombolysis in myocardial infarction flow grade 3, particularly in cases of cardiogenic shock. A 49-year-old man who presented with anterior ST-segment elevated acute myocardial infarction with cardiogenic shock underwent emergency percutaneous coronary intervention to diffuse proximal lesions in the left anterior descending artery under the support of intra-aortic balloon pumping. Intraprocedural stent thrombosis occurred following the postdilations with a 3.5- × 38-mm everolimus-eluting stent. Despite administration of argatroban and nitroprusside, and after frequent balloon inflations using 3.5-mm noncompliant balloons and thrombectomy, the no-reflow phenomenon was repetitively established. However, after brief and prolonged balloon inflations using 3.5- and 3-mm Ryusei perfusion balloon catheters (Kaneka Medix), the diffusely protruded thrombus inside the stent regressed, and thrombolysis in myocardial infarction flow grade 3 was obtained. The final intravascular ultrasound image showed a well-suppressed, in-stent thrombus and 24% gain of stent area (from 7.5 to 9.3 mm2). A Ryusei perfusion balloon enabled frequent, long inflation times without deteriorating hemodynamics during reperfusion in ST-segment elevated acute myocardial infarction complicated with cardiogenic shock. Thus, extended balloon inflation using a perfusion balloon is deemed a viable option not only for intraprocedural stent thrombosis but also for cases with a high burden of thrombi during the primary stenting procedure for patients with acute coronary syndrome.

The optimal alternative anticoagulation regimen for patients with heparin-induced thrombocytopenia (HIT) who need surgical procedures that involve higher levels of anticoagulation, usually performed under heparin, is not yet established. Argatroban has been reported as a safe alternative. Plasma levels and their anticoagulant effects follow a predictable profile. Also, it is easily monitored and its pharmacokinetic profile makes it suitable for patients with renal failure, as it undergoes hepatic elimination. However, its use as a substitute for heparin in HIT patients is not well-documented, especially in vascular surgery. We present a case of a successfully managed patient with acute HIT undergoing limb vascular surgery using anticoagulation with argatroban.

In the absence of known thrombophilia or factors associated with thrombotic tendency, clinicians are more likely to think of antiphospholipid syndrome in patients presenting with venous thrombosis than in those with arterial thrombosis. We present a case of acute lower extremity arterial ischemia in a female smoker. Despite multiple surgical interventions and treatment with several different anticoagulants, our patient developed bilateral lower extremity thrombi. Ultimately, after developing a pulmonary embolism, she accepted to be on warfarin. She switched to warfarin without recurrence of her arterial thrombosis. We describe the challenging management of her critical limb ischemia and review the pertinent literature on the controversy surrounding optimal anticoagulation in such patients.

Heparin-induced thrombocytopenia (HIT) is characterized by low platelets and thrombosis after exposure to Heparin products. It is classically characterized by a rapid and significant drop in platelets and life-threatening thrombosis. Thrombosis can occur up to 50% of the cases if left untreated. It requires immediate discontinuation of all heparin products and switching to a non-heparin anticoagulant to prevent further thrombosis. Here we present a case of a 56-year-old male who presented to the Emergency Department with sudden onset of severe left leg pain. Duplex study showed arterial thrombosis in the common iliac and distal iliac arteries. He received TPA at once and underwent thrombectomy while his platelet continued to drop. He used Low Molecular Weight Heparin (enoxaparin) for bridging after his tonsil surgery a week prior to this hospital admission. His HIT assay was found to be positive and despite the Argatroban therapy his clinical condition continued to worsen while his platelet count continued to drop. Given the refractory nature of the thrombosis and thrombocytopenia; Intravenous immunoglobulin (IVIG) therapy was introduced. The patient showed a great response and his platelet count improved to 150,000/μ. He was discharged on warfarin with a closer follow-up. Few case reports have described the treatment of such refractory cases using intravenous immunoglobulin (IVIG), resulting in stabilized platelet counts, reduced platelet activation, and reduced thrombotic complications, the exact mechanism of which is unknown. It is thought that IVIG inhibits platelet activation by binding as platelet receptors, which would otherwise bind with heparin-platelet factor 4 complexes and HIT antibodies.

Argatroban is a medication used in the management of heparin-induced thrombocytopenia (HIT), which is a rare, life-threatening complication of heparin therapy. It is a direct thrombin inhibitor, a class of anticoagulant drugs. This activity outlines the indications, action, and contraindications for argatroban as a valuable agent in the prophylaxis and treatment of thrombosis in patients with HIT. This activity also highlights the mechanism of action, adverse event profile, and other key factors (e.g., off-label uses, dosing, pharmacodynamics, pharmacokinetics, monitoring, relevant interactions) pertinent for members of the healthcare team in the management of patients with heparin-induced thrombocytopenia.

In Covid-19, anticoagulation with heparin is often administered to prevent or treat thromboembolic events. Heparin-induced thrombocytopenia (HIT) is a severe complication of heparin treatment, caused by heparin-dependent, platelet activating anti-platelet factor 4 (PF4)/heparin antibodies. Diagnosis of HIT is based on the combination of clinical parameters, allowing to determine the pretest probability, and laboratory testing for anti-PF4/heparin antibodies and confirmatory functional assays, such as the heparin-induced platelet activation (HIPA) test.We report the case of a patient with severe Covid-19 pneumonia requiring ECMO treatment, who developed recurrent clotting of the ECMO filter and a drop in platelet count under heparin treatment. He was therefore suspected to have HIT and the anticoagulation was switched to argatroban. Despite high clinical probability and high titres of anti-PF4/heparin antibodies, the functional HIPA test was negative. Nevertheless, argatroban was continued rather than to reinstate anticoagulation with heparin. Reevaluation 7 days later then demonstrated a strongly positive functional HIPA test and confirmed the diagnosis of HIT. Under anticoagulation with argatroban the patient gradually improved and was finally weaned off the ECMO.In conclusion, this case highlights the critical importance of clinical judgement, exploiting the 4 T score, given that Covid-19 patients may present a different pattern of routine laboratory test results in HIT diagnostics. The possibility of a false negative HIPA test has to be considered, particularly in early phases of presentation. In cases of a discrepancy with high clinical probability of HIT and/or high titre anti-PF4/heparin antibodies despite a negative HIPA test, a reevaluation within 3 to 5 days after the initial test should be considered in order to avoid precipitant reestablishment of unfractionated heparin, with potentially fatal consequences.

This report discusses a case of a 37-year-old female who developed vaccine-induced thrombotic thrombocytopenia (VITT) after receiving the Johnson and Johnson COVID-19 vaccination. The patient first presented to the ED with complaints of a worsening headache. Labs were significant for thrombocytopenia with a platelet count of 22,000, and the patient was admitted to the inpatient unit for monitoring. The day after admission, the patient was found to have a right common femoral artery embolus, left distal popliteal trifurcation embolism, a small pulmonary embolism in the right lower lobe, and a mural thrombus of the infrarenal abdominal aorta. Following these findings, the patient underwent emergent thrombectomy of the common and superficial femoral arteries. Over the hospital course of six days, the patient received steroids and IV immunoglobulin (IVIG), which led to the resolution of the thrombocytopenia. The patient was given argatroban followed by apixaban for anticoagulation. She was instructed to follow up with hematology within one to two weeks post-discharge for monitoring of anticoagulation and thrombus surveillance. This case report outlines the clinical course, diagnosis, and treatment of a case of VITT, which will assist physicians in early recognition and adequate treatment of this condition as the COVID-19 pandemic continues.

Severe tuberculosis during pregnancy may progress to acute respiratory distress syndrome (ARDS), and venovenous (VV) extracorporeal membrane oxygenation (ECMO) should be considered if conventional lung-protective mechanical ventilation fails. However, thrombocytopenia often occurs with ECMO, and there are limited reports of alternative anticoagulant therapies for pregnant patients with thrombocytopenia during ECMO. This report describes the first case of a pregnant patient who received argatroban during ECMO and recovered. Furthermore, we summarized the existing literature on VV-ECMO and argatroban in pregnant patients. A 31-year-old woman at 17 weeks of gestation was transferred to our hospital with ARDS secondary to severe tuberculosis. We initiated VV-ECMO after implementing a protective ventilation strategy and other conventional therapies. Initially, we selected unfractionated heparin anticoagulant therapy. However, on ECMO day 3, the patient's platelet count and antithrombin III (AT-III) level declined to 27 × 103 cells/μL and 26.9%, respectively. Thus, we started the patient on a 0.06 μg/kg/min argatroban infusion. The argatroban infusion maintenance dose ranged between 0.9 and 1.2 μg/kg/min. The actual activated partial thromboplastin clotting time and activated clotting time ranged from 43 to 58 s and 220-260 s, respectively, without clinically significant bleeding and thrombosis. On day 27, the patient was weaned off VV-ECMO and eventually discharged. VV-ECMO may benefit pregnant women with refractory ARDS, and argatroban may be an alternative anticoagulant for pregnant patients with thrombocytopenia and AT-III deficiency during ECMO.

Bleeding and thrombosis frequently occur in pediatric patients with extracorporeal membrane oxygenation (ECMO) therapy. Until now, most patients are anticoagulated with unfractionated heparin (UFH). However, heparin has many disadvantages, such as binding to other plasma proteins and endothelial cells in addition to antithrombin, causing an unpredictable response, challenging monitoring, development of heparin resistance, and risk of heparin-induced thrombocytopenia (HIT). Direct thrombin inhibitors (DTIs), such as bivalirudin and argatroban, might be a good alternative. This review will discuss the use of both UFH and DTIs in pediatric patients with ECMO therapy.