Argatroban therapy for heparin-induced thrombocytopenia in ICU patients with multiple organ dysfunction syndrome: a retrospective study

Anticoagulation strategies in patients with extracorporeal membrane oxygenation: A network meta-analysis and systematic review

OBJECTIVES

Extracorporeal membrane oxygenation (ECMO) plays an important role in providing temporary life support for patients with severe cardiac or pulmonary failure, but requires strict anticoagulation and monitoring. This network meta-analysis systematically explored the most effective anticoagulation and monitoring strategies for patients receiving ECMO.

METHODS

MEDLINE, Embase, Web of Science, and the Cochrane Central Register of Controlled Trials were searched up to January 31, 2023, for studies comparing unfractionated heparin (UFH), argatroban (Arg), bivalirudin (Biv), and/or nafamostat mesylate (NM) in patients receiving ECMO. The primary outcomes included device-related thrombosis, patient-related thrombosis, and major bleeding events. The secondary outcomes included ECMO survival, ECMO duration, and in-hospital mortality.

RESULTS

A total of 2522 patients from 23 trials were included in the study. Biv was associated with a decreased risk of device-related thrombosis (odd ratio [OR] 0.51, 95% confidence interval [CI]: 0.33-0.84) compared with UFH, whereas NM (OR 2.2, 95% CI: 0.24-65.0) and Arg (OR 0.92, 95% CI: 0.43-2.0) did not reduce the risk of device-related thrombosis compared with UFH. Biv was superior to Arg in decreasing the risk of device-related thrombosis (OR 0.14, 95% CI: 0.03-0.51). Biv reduced the risk of patient-related thrombosis compared with UFH (OR 0.44, 95% CI: 0.18-0.85); NM (OR 0.65, 95% CI: 0.14-3.3) and Arg (OR 3.1, 95% CI: 0.94-12.0) did not decrease risk of patient-related thrombosis compared with UFH. No significant difference was observed in the risk of major bleeding between three alternatives and UFH: Biv (OR 0.54, 95% CI: 0.23-1.3), Arg (OR 1.3, 95% CI: 0.34-5.8), and NM (OR 0.60, 95% CI: 0.13-2.6). NM showed a reduced risk of in-hospital mortality compared with UFH (OR 0.27, 95% CI: 0.091-0.77), whereas Arg (OR 0.43, 95% CI: 0.15-1.2) and Biv (OR 0.75, 95% CI: 0.52-1.1) did not decrease risk of in-hospital mortality.

CONCLUSIONS

Compared with UFH and Arg, Biv reduces the risk of thrombosis and appears to be a better choice for patients requiring ECMO. NM was associated with a reduced risk of in-hospital mortality.

Update on Anticoagulation Strategies in Patients with ECMO-A Narrative Review

The use of extracorporeal membrane oxygenation (ECMO) has recently increased exponentially. ECMO has become the preferred mode of organ support in refractory respiratory or circulatory failure. The fragile balance of haemostasis physiology is massively altered by the patient's critical condition and specifically the aetiology of the underlying disease. Furthermore, an application of ECMO conveys another disturbance of haemostasis due to blood-circuit interaction and the presence of an oxygenator. The purpose of this review is to summarise current knowledge on the anticoagulation management in patients undergoing ECMO therapy. The unfractionated heparin modality with monitoring of activated partial thromboplastin tests is considered to be a gold standard for anticoagulation in this specific subgroup of intensive care patients. However, alternative modalities with other agents are comprehensively discussed. Furthermore, other ways of monitoring can represent the actual state of coagulation in a more complex fashion, such as thromboelastometric/graphic methods, and might become more frequent. In conclusion, the coagulation system of patients with ECMO is altered by multiple variables, and there is a significant lack of evidence in this area. Therefore, a highly individualised approach is the best solution today.

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

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

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

During sepsis, an initial prothrombotic shift takes place, in which coagulatory acute-phase proteins are increased, while anticoagulatory factors and platelet count decrease. Further on, the fibrinolytic system becomes impaired, which contributes to disease severity. At a later stage in sepsis, coagulation factors may become depleted, and sepsis patients may shift into a hypo-coagulable state with an increased bleeding risk. During the pro-coagulatory shift, critically ill patients have an increased thrombosis risk that ranges from developing micro-thromboses that impair organ function to life-threatening thromboembolic events. Here, thrombin plays a key role in coagulation as well as in inflammation. For thromboprophylaxis, low molecular weight heparins (LMWH) and unfractionated heparins (UFHs) are recommended. Nevertheless, there are conditions such as heparin resistance or heparin-induced thrombocytopenia (HIT), wherein heparin becomes ineffective or even puts the patient at an increased prothrombotic risk. In these cases, argatroban, a direct thrombin inhibitor (DTI), might be a potential alternative anticoagulatory strategy. Yet, caution is advised with regard to dosing of argatroban especially in sepsis. Therefore, the starting dose of argatroban is recommended to be low and should be titrated to the targeted anticoagulation level and be closely monitored in the further course of treatment. The authors of this review recommend using DTIs such as argatroban as an alternative anticoagulant in critically ill patients suffering from sepsis or COVID-19 with suspected or confirmed HIT, HIT-like conditions, impaired fibrinolysis, in patients on extracorporeal circuits and patients with heparin resistance, when closely monitored.

Use of an argatroban systemic infusion and purge solution in a patient with a percutaneous ventricular assist device with suspected heparin-induced thrombocytopenia

DISCLAIMER

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PURPOSE

Thrombocytopenia can occur when using an Impella percutaneous ventricular assist device (pVAD), and heparin-induced thrombocytopenia (HIT) is often suspected. Data on heparin- and anticoagulant-free purge solutions in these devices are limited. Previous case reports have described argatroban-based purge solutions, both with and without systemic argatroban, at varying concentrations in patients with known or suspected HIT.

SUMMARY

A 33-year-old male was transferred to our institution and emergently initiated on life support with venoarterial extracorporeal membrane oxygenation (ECMO), an Impella pVAD, and continuous venovenous hemofiltration to receive an urgent aortic valve replacement. Over the next several days, the patient's platelet count declined with a nadir of 17 × 10 3/µL on hospital day 13. The patient's 4T score for probability of HIT was calculated as 4. All heparin products were discontinued on hospital day 15, and the patient was initiated on systemic infusion with argatroban 1,000 µg/mL at a rate of 0.2 µg/kg/min with a purge solution of argatroban 0.05 mg/mL. The systemic infusion remained at a rate of 0.2 µg/kg/min, and the total argatroban dose was, on average, less than 0.25 µg/kg/min. On hospital day 21, the patient was transferred to another institution.

CONCLUSION

Systemic infusion and a purge solution with argatroban were used in a patient with an Impella pVAD with multisystem organ dysfunction and suspected HIT. The patient achieved therapeutic activated partial thromboplastin times without adjustment of the systemic argatroban infusion and did not experience bleeding or thrombosis. Further studies concerning the safety and effectiveness of argatroban-based purge solutions in patients with pVADs are needed.

Argatroban Anticoagulation for Adult Extracorporeal Membrane Oxygenation: A Systematic Review

BACKGROUND

Heparin is the widely used anti-coagulation strategy for patients on extracorporeal membrane oxygenation (ECMO). Nevertheless, heparin-induced thrombocytopenia (HIT) and acquired anti-thrombin (AT) deficiency preclude the use of heparin requiring utilization of an alternative anticoagulant agent. Direct thrombin inhibitors are being proposed as potential alternatives with argatroban as one of the main agents. We aimed to review the evidence with regard to safety and efficacy of argatroban as a potential definitive alternative to heparin in the adult patient population undergoing ECMO support.

METHODS

A web-based systematic literature search was performed in Medline (PubMed) and Embase from inception until June 18, 2020.

RESULTS

The search identified 13 publications relevant to the target (4 cohort studies and 9 case series). Case reports and case series with less than 3 cases were not included in the qualitative synthesis. The aggregate number of argatroban treated patients on ECMO was n = 307. In the majority of studies argatroban was used as a continuous infusion without loading dose. Starting doses on ECMO varied between 0.05 and 2 μg/kg/min and were titrated to achieve the chosen therapeutic target range. The activated partial thormboplastin time (aPTT) was the anticoagulation parameter used for monitoring purposes in most studies, whereas some utilized the activated clotting time (ACT). Optimal therapeutic targets varied between 43-70 and 60-100 seconds for aPTT and between 150-210 and 180-230 seconds for ACT. Bleeding and thromboembolic complication rates were comparable to patients treated with unfractionated heparin (UFH).

CONCLUSIONS

Argatroban infusion rates and anticoagulation target ranges showed substantial variations. The rational for divergent dosing and monitoring approaches are discussed in this paper. Argatroban appears to be a potential alternative to UFH in patients requiring ECMO. To definitively establish its safety, efficacy and ideal dosing strategy, larger prospective studies on well-defined patient populations are warranted.

A Prospective Pilot Trial to Assess the Efficacy of Argatroban (Argatra®) in Critically Ill Patients with Heparin Resistance

The current study aims to evaluate whether prophylactic anticoagulation using argatroban or an increased dose of unfractionated heparin (UFH) is effective in achieving the targeted activated partial thromboplastin time (aPTT) of more than 45 s in critically ill heparin-resistant (HR) patients. Patients were randomized either to continue receiving an increased dose of UFH, or to be treated with argatroban. The endpoints were defined as achieving an aPTT target of more than 45 s at 7 h and 24 h. This clinical trial was registered on clinicaltrials.gov (NCT01734252) and on EudraCT (2012-000487-23). A total of 42 patients, 20 patients in the heparin and 22 in the argatroban group, were included. Of the patients with continued heparin treatment 55% achieved the target aPTT at 7 h, while only 40% of this group maintained the target aPTT after 24 h. Of the argatroban group 59% reached the target aPTT at 7 h, while at 24 h 86% of these patients maintained the targeted aPTT. Treatment success at 7 h did not differ between the groups (p = 0.1000), whereas at 24 h argatroban showed significantly greater efficacy (p = 0.0021) than did heparin. Argatroban also worked better in maintaining adequate anticoagulation in the further course of the study. There was no significant difference in the occurrence of bleeding or thromboembolic complications between the treatment groups. In the case of heparin-resistant critically ill patients, argatroban showed greater efficacy than did an increased dose of heparin in achieving adequate anticoagulation at 24 h and in maintaining the targeted aPTT goal throughout the treatment phase.

Scrub typhus with multi-organ dysfunction syndrome and immune thrombocytopenia: a case report and review of the literature

BACKGROUND

Scrub typhus is an acute infectious zoonotic disease caused by Orientia tsutsugamushi. Multi-organ dysfunction secondary to scrub typhus is hard to diagnose and has a high mortality rate. Only one case of scrub typhus with multi-organ dysfunction syndrome and immune thrombocytopenia has been reported thus far. In this study, we report a second case of scrub typhus with multi-organ dysfunction syndrome and immune thrombocytopenia, and we summarize its diagnosis and treatment.

CASE PRESENTATION

A 43-year-old Han Chinese woman, a sanitation worker, was admitted to our hospital after 7 days of a skin infection and 5 days of a sore throat with fever and dizziness. A physical examination revealed the presence of an eschar on the right side of her neck. She had a history of insect bites during her sanitation work. A diagnostic evaluation identified scrub typhus as the primary illness, which was associated with multi-organ dysfunction syndrome and immune thrombocytopenia. She recovered completely after 15 days of treatment and extensive symptomatic supportive care.

CONCLUSION

We report a second case of tsutsugamushi disease with multi-organ dysfunction syndrome and immune thrombocytopenia, which resolved after treatment and extensive care.

European guidelines on perioperative venous thromboembolism prophylaxis: Intensive care

: Venous thromboembolism is a common and potentially life-threatening complication that occurs in 4 to 15% of patients admitted to ICUs despite the routine use of pharmacological prophylaxis. We therefore recommend an institution-wide protocol for the prevention of venous thromboembolism (Grade 1B). The routine use of ultrasonographic screening for deep vein thrombosis is not recommended when thromboprophylactic measures are in place (Grade 1B), as the detection of asymptomatic deep vein thrombosis may prompt therapeutic anticoagulation that may increase bleeding risk but has no proven reduction of clinically significant thrombotic events. In critically ill patients, we recommend pharmacological prophylaxis with low molecular weight heparin over low-dose heparin (Grade 1B). For critically ill patients with severe renal insufficiency, we suggest the use of low-dose heparin (Grade 2C), dalteparin (Grade 2B) or reduced doses of enoxaparin (Grade 2C). Monitoring of anti-Xa activity may be considered when low molecular weight heparin is used in these patients (Grade 2C). No study has prospectively evaluated the efficacy and safety of deep vein thrombosis prophylaxis in critically ill patients with severe liver dysfunction. Thus, the use of pharmacological prophylaxis in these patients should be carefully balanced against the risk of bleeding. For critically ill patients, we recommend against the routine use of inferior vena cava filters for the primary prevention of venous thromboembolism (Grade 1C). When the diagnosis of heparin-induced thrombocytopaenia is suspected or confirmed, all forms of heparin must be discontinued (Grade 1B). In these patients, immediate anticoagulation with a nonheparin anticoagulant rather than discontinuation of heparin alone is recommended (Grade 1C).

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.

Continuous Renal Replacement Therapy and Anticoagulation: What Are the Options?

Continuous renal replacement therapy is currently used as a standard treatment for acute kidney injury in the intensive care unit, particularly for patients with unstable hemodynamic status. Because this therapy is continuous, for days or weeks, and the extracorporeal blood circuit is large, the circuit is prone to clotting. Several methods of keeping the extracorporeal circuit patent are available, including heparin infusion, flushes with physiological saline, use of thrombin inhibitors, and citrate. This article reviews methods for continuous renal replacement therapy, anticoagulation, efficacy, and implications for bedside critical care.

Argatroban dosing in obesity

PURPOSE

Obesity is associated with significant alterations in pharmacokinetic and pharmacodynamic properties. The use of weight based anticoagulants such as argatroban may put obese patients at an increased risk of hemorrhagic events. The purpose of this study was to evaluate argatroban dosing requirements in obese vs non-obese patients.

METHODS

This single-center, retrospective cohort study included patients ≥18 years with suspected HIT, treated with argatroban for ≥12 h. Patients were stratified by body mass index (BMI) into obese (BMI > 30 kg/m²) and non-obese (BMI ≤ 30 kg/m²) groups. The primary outcome was the median maintenance dose required to achieve two consecutive therapeutic activated partial thromboplastin times.

RESULTS

A total of 121 patients were included. The median BMI in the obese vs non-obese groups was 35.8 vs 24.05 kg/m² (p < .0001). Although statistically significant, there was no clinically significant difference in median maintenance argatroban dose in obese versus non-obese patients (1 vs 1 μg/kg/min; p = .01). In-hospital major bleeding and in-hospital thrombosis also did not differ between the two groups.

CONCLUSION

Obese patients require similar median argatroban maintenance doses when compared to non-obese patients. Based on these results argatroban should be dosed using actual body weight regardless of BMI.

Argatroban pharmacokinetics and pharmacodynamics in critically ill cardiac surgical patients with suspected heparin-induced thrombocytopenia

Only limited data are available on the pharmacokinetic and pharmacodynamic properties of argatroban in critically ill patients under clinical conditions. We determined plasma concentrations of argatroban, and its main metabolite M1, within a time period of 48 hours in 25 critically ill cardiac surgical patients, who were suspected of heparininduced thrombocytopenia and had the clinical need for anticoagulation. Argatroban infusion was started at 0.5 µg/kg/minute, and adjusted in 0.1–0.25 µg/kg/minute increments when the activated partial thromboplastin time (aPTT) was not within the target range. Median argatroban plasma half-life was 2.7 hours (interquartile range 1.8 to 7.3). Linear regression analysis revealed that argatroban half-life was significantly related to the total bilirubin concentration (R2 = 0.66, p< 0.001), as well as to the metabolism of argatroban, which was assessed by the ratio of the areas under the concentration time curves (AUC) of argatroban and M1 (R2 = 0.60, p< 0.001). Continuous veno-venous haemodialysis did not significantly affect argatroban plasma half-life. The predictive property of argatroban plasma levels for aPTT was low (R2 = 0.28, p< 0.001). Multiple linear regression analysis revealed significant contributions of age and serum albumin levels to the effect of argatroban on aPTT, expressed as the AUC ratio argatroban/aPTT (R2 = 0.67, adjusted R2 = 0.65, p< 0.001). In conclusion, argatroban plasma half-life is markedly increased in critically ill cardiac surgical patients, and further prolonged by hepatic dysfunction due to impaired metabolism. Patient age and serum albumin concentration significantly contribute to the variability in the anticoagulant activity of argatroban.

Efficacy and safety of argatroban in patients with acute respiratory distress syndrome and extracorporeal lung support

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) or pumpless extracorporeal lung assist (pECLA) requires effective anticoagulation. Knowledge on the use of argatroban in patients with acute respiratory distress syndrome (ARDS) undergoing ECMO or pECLA is limited. Therefore, this study assessed the feasibility, efficacy and safety of argatroban in critically ill ARDS patients undergoing extracorporeal lung support.

METHODS

This retrospective analysis included ARDS patients on extracorporeal lung support who received argatroban between 2007 and 2014 in a single ARDS referral center. As controls, patients who received heparin were matched for age, sex, body mass index and severity of illness scores. Major and minor bleeding complications, thromboembolic events, administered number of erythrocyte concentrates, thrombocytes and fresh-frozen plasmas were assessed. The number of extracorporeal circuit systems and extracorporeal lung support cannulas needed due to clotting was recorded. Also assessed was the efficacy to reach the targeted activated partial thromboplastin time (aPTT) in the first consecutive 14 days of therapy, and the controllability of aPTT values is within a therapeutic range of 50-75 s. Fisher's exact test, Mann-Whitney U tests, Friedman tests and multivariate nonparametric analyses for longitudinal data (MANOVA; Brunner's analysis) were applied where appropriate.

RESULTS

Of the 535 patients who met the inclusion criteria, 39 receiving argatroban and 39 matched patients receiving heparin (controls) were included. Baseline characteristics were similar between the two groups, including severity of illness and organ failure scores. There were no significant differences in major and minor bleeding complications. Rates of thromboembolic events were generally low and were similar between the two groups, as were the rates of transfusions required and device-associated complications. The controllability of both argatroban and heparin improved over time, with a significantly increasing probability to reach the targeted aPTT corridor over the first days (p < 0.001). Over time, there were significantly fewer aPTT values below the targeted aPTT goal in the argatroban group than in the heparin group (p < 0.05). Both argatroban and heparin reached therapeutic aPTT values for adequate application of extracorporeal lung support.

CONCLUSIONS

Argatroban appears to be a feasible, effective and safe anticoagulant for critically ill ARDS patients undergoing extracorporeal lung support.

D-dimer Is a Predictor of 28-Day Mortality in Critically Ill Patients Receiving Continuous Renal Replacement Therapy

BACKGROUND AND AIMS

Continuous renal replacement therapy (CRRT) is an important treatment in the intensive care unit (ICU). Nevertheless, the outcome of CRRT remains unclear. It is important to find a useful and easy indicator to predict the prognosis in patients on CRRT treatment. We undertook this study to observe the association between serum D-dimer level and mortality of ICU patients in the treatment of CRRT.

METHODS

A total of 149 patients who received CRRT were enrolled in our study. We observed the correlation of D-dimer with the information of biochemical parameters, acute physiology and chronic health evaluation II (APACHE II) score. We analyzed the association between serum D-dimer level before CRRT and 28-d mortality retrospectively. Furthermore, we used Cox regression analysis to assess whether D-dimer could be the independent risk factor for mortality.

RESULTS

There were significant correlations between D-dimer and C-reaction protein (r² = 0.033, p = 0.026), creatinine (r² = 0.066, p = 0.002) and APACHE II (r² = 0.036, p = 0.021). The difference in 28-d mortality risk between elevated D-dimer group and normal D-dimer group was significant (HR 2.872, 95% CI 1.563-5.278, p = 0.001), and the elevated D-dimer level was an independent risk factor for 28-d mortality (HR 2.067, 95% CI 1.104-3.872, p = 0.023). The difference in 28-d mortality was significant between groups (p <0.001). ROC curves showed that the area under the curve (AUC) of D-dimer was 0.763.

CONCLUSION

The present study demonstrates that serum D-dimer could be a useful and easy prognostic variable of 28-d mortality in critically ill patients who received CRRT.

[Heparin-induced thrombocytopenia type II (HIT II) : A medical-economic view]

BACKGROUND

In the context of inpatient and increasingly ambulatory thrombosis prophylaxis, heparins have been recognised as standard therapy for decades. In addition to the therapeutic benefit, therapy with heparins also entails the risk of undesirable side effects, such as bleeding and thrombocytopenia. Heparin-induced thrombocytopenia (HIT II) is deemed a serious side effect.

AIM

In the following work, HIT II is subjected to a medico-economic consideration (treatment, pharmaceuticals, subsequent costs due to possible complications) and, with regard to a possible HIT II prophylaxis, aspects of increasingly respected patient safety are also considered.

METHODS

In the context of a literature search the active ingredients argatroban and danaparoid, which are approved for HIT II treatment, were evaluated.

RESULTS

HIT II - especially in combination with thromboembolic complications - represents a medical-economic burden for the hospital. Although this is only an orientation guide, it shows that HIT II syndrome is not adequately cost-covered by the G‑DRG system. An early thrombosis prophylaxis with argatroban/danaparoid for HIT II risk patients should therefore be taken into account for medical-related as well as patient safety-relevant aspects. According to experience, the pharmaceutical supply for these medically needed products (anticoagulants) should be ensured for reasons of patient safety.

CONCLUSION

The risk of an immunological response to heparin therapy is known. Within the context of increased patient safety, thrombosis prophylaxis should be issued with a risk-adjusted prophylaxis.

Argatroban in the management of heparin-induced thrombocytopenia: a multicenter clinical trial

Introduction

The aim of this study was to collect data in France in patients with heparin-induced thrombocytopenia who required parenteral anticoagulation and for whom other non-heparin anticoagulant therapies were contraindicated including patients with renal failure, cross-reactivity to danaparoid or at high hemorrhagic risk.

Methods

A total of 20 patients, of mean age 72 ± 10 years, were enrolled in this open-label, multicenter clinical study. Exploratory statistical data analysis was performed with descriptive interpretation of intra-individual comparisons using simple univariate statistics.

Results

The diagnosis of HIT was confirmed in 16 subjects by an independent scientific committee. Fourteen patients (70 %) were in an intensive care unit during the course of the study. Patients were treated with argatroban for a mean duration of 8.5 ± 6.1 days. The mean starting dose of argatroban was 0.77 ± 0.45 μg/kg/min. Platelet recovery was rapid.

aPTT and anti-IIa activity assays were used to monitor the dose of argatroban. The mean baseline aPTT value was 45.0 ± 9.8 sec and increased to 78.2 ± 35.8 sec two hours after initiating argatroban. At this time mean argatroban concentration was 0.34 ± 0.16 and 0.61 ± 0.28 μg/ml using ECT and TT measurements, respectively. New and/or extended thromboses were reported in 25 % of patients and major bleedings were documented in 15 %. Six patients died due to their underlying medical condition.

Conclusion

Considering its hepatic elimination and its short half-life, argatroban can be considered as a safe therapeutic option in HIT patients at high hemorrhagic risk and with renal failure, particularly in an ICU setting.

Heparin-induced thrombocytopenia in a non-heparin-naive patient: a case report

Introduction

Administration of low molecular weight heparin (LMWH) is recommended for prophylaxis of venous thromboembolism in patients undergoing hip surgery. In this context, heparin-induced thrombocytopenia (HIT) type II is a complication of rare incidence but sometimes fatal outcome.

Case description

A 52-year old obese patient undergoing antithrombotic therapy with Enoxaparin after hip surgery presented with a painful, swollen leg and thrombocytopenia on day eight after surgery. Medical history showed previous administration of Enoxaparin without complications 2 years ago. Further diagnostic investigation supplied evidence of multiple thromboembolic events and concomitant compartment syndrome. Administration of Enoxaparin was stopped immediately and treatment with Argatroban was initiated. Diagnosis of HIT was confirmed according to current guidelines. Despite interventional thrombectomy and fasciotomy, amputation of both lower limbs had to be performed due to ongoing necroses. After a 30-days-stay at the intensive care unit because of sepsis, respiratory and renal failure, clinical condition improved and the patient could be transferred for rehabilitation.

Discussion and evaluation

HIT II is known as complication of administration of LMWH in the perioperative setting. Diagnosis results from clinical findings and platelet count. Argatroban is recommended as an alternative therapeutic anticoagulant in HIT II. Inflammation and surgical trauma are discussed as priming factors to increase risk of HIT II.

Conclusions

Administration of LMWH may result in HIT II despite prior uneventful drug exposure. Except for immediate diagnosis, only consequent anticoagulation can stop the course of disease. Hence, interdisciplinary awareness is inevitable for early diagnosis and accurate therapy to prevent from a catastrophic clinical course.

Safety and economic considerations of argatroban use in critically ill patients: a retrospective analysis

Background

Heparin-induced thrombocytopenia (HIT) causes thromboembolic complications which threaten life and limb. Heparin is administered to virtually every critically ill patient as a protective measure against thromboembolism. Argatroban is a promising alternative anticoagulant agent. However, a safe dose which still provides effective thromboembolic prophylaxis without major bleeding still needs to be identified.

Methods

Critically ill patients (n = 42) diagnosed with HIT at a tertiary medical center intensive care unit from 2005 to 2010 were included in this retrospective analysis. Patient records were perused for preexisting history of HIT, heparin dosage before HIT, argatroban dosage, number of transfusions required, thromboembolic complications and length of ICU stay (ICU LOS). Patients were allocated to Simplified Acute Physiology Scores above and below 30 (SAPS >30, SAPS <30), respectively. For calculations, patients (n = 19) without previous history of HIT were compared to patients (n = 23) with a history of HIT before initiation of argatroban.

Results

The mean initial argatroban dosage was below 0.4 mcg/kg/min regardless of SAPS score. Maintenance dosage had to be increased in patients with SAPS <30 to 0.54 ± 0.248 mcg/kg/min (p >0.05) to achieve effective anticoagulation. No thromboembolic complications were encountered. Argatroban had to be discontinued temporarily in 16 patients for a total of 57 times due to diagnostic or surgical procedures, supratherapeutic aPTT and bleeding without increasing the number of transfusions. A history of HIT was associated with a shorter ICU LOS and significantly reduced transfusion need when compared to patients with no history of HIT. Cost calculation favour argatroban due to increased transfusion needs during heparin administration and increase ICU LOS.

Conclusion

Argatroban can be used at doses < 0.4 mcg/kg/min without an increase in transfusion requirements and at a reduced overall treatment cost compared to heparin.

Drug-Induced Immune Thrombocytopenia

Thrombocytopenia is commonly seen in laboratory findings, especially in critically ill patients. Although the incidence is rare, drug-induced immune thrombocytopenia (DITP) is a serious complication that is often overlooked as a cause of thrombocytopenia. Over the last century, extensive research and data collection have been done in an attempt to better characterize DITP. Heparin-induced thrombocytopenia is the most common DITP and has distinct pathogenesis, diagnosis, and treatment options. However, other offending medications are less well known and have triggered many questions and constant search for answers. This review will discuss both drug-induced immune-mediated and nonimmune-mediated thrombocytopenias, with a focus on immune-mediated processes. Thrombocytopenia caused by chemotherapy will not be discussed in this article.

Update on argatroban for the prophylaxis and treatment of heparin-induced thrombocytopenia type II

Heparin-induced thrombocytopenia (HIT) is a rare but potentially severe complication of heparin therapy that is strongly associated with venous and arterial thrombosis (HIT and thrombosis syndrome, HITTS), which requires urgent detection and treatment with a nonheparin anticoagulant. Argatroban, a synthetic direct thrombin inhibitor, is indicated for the treatment and prophylaxis of thrombosis in patients with HIT, including those undergoing percutaneous coronary intervention. Argatroban has a relatively short elimination half-life of approximately 45 minutes, which is predominantly performed via hepatic metabolism. It is derived from L-arginine that selectively and reversibly inhibits thrombin, both clot-bound and free, at the catalytic site. Argatroban anticoagulation has been systematically studied in patients with HIT and HITTS and proved to be a safe and effective agent for this indication. The current review presents the pharmacology of argatroban, data regarding monitoring of the agent, and an overview of the results of the major clinical trials assessing argatroban anticoagulation in HIT patients. Additionally, data from recent clinical trials with argatroban use in more special indications such as in percutaneous coronary intervention, liver dysfunction, renal replacement therapy, and intensive care medicine, are reviewed. The approved initial dosage of argatroban for adults with HIT or HITTS is 2 μg/kg/minute for patients with normal hepatic function and 0.5 μg/kg/minute for patients with hepatic dysfunction. There is evidence that a reduced initial dose may also be advisable for patients with heart failure, multiple organ dysfunction, severe anasarca, or after cardiac surgery. Given this information, argatroban can be effectively used in treating HIT with monitoring of activated partial thromboplastin time.

Decreased platelet count in patients receiving continuous veno-venous hemofiltration: a single-center retrospective study

BACKGROUND

A decreased platelet count may occur and portend a worse outcome in patients receiving continuous renal replacement therapy (CRRT). We aim to investigate the incidence of decreased platelet count and related risk factors in patients receiving CRRT.

METHODS

In this retrospective study, we screened all patients receiving continuous veno-venous hemofiltration (CVVH) at Jinling Hospital between November 2008 and October 2012. The patients were included who received uninterrupted CVVH for more than 72 h and had records of blood test for 4 consecutive days after ruling out pre-existing conditions that may affect the platelet count. Platelet counts before and during CVVH, illness severity, CVVH settings, and outcomes were analyzed.

RESULTS

The study included 125 patients. During the 3-day CVVH, 44.8% and 16% patients had a mild decline (20-49.9%) and severe decline (≥ 50%) in the platelet count,respectively; 37.6% and 16.0% patients had mild thrombocytopenia (platelet count 50.1-100 × 109/L) and severe thrombocytopenia (platelet count ≤ 50 × 10(9)/L), respectively. Patients with a severe decline in the platelet count had a significantly lower survival rate than patients without a severe decline in the platelet count (35.0% versus 59.0%, P=0.012), while patients with severe thrombocytopenia had a survival rate similar to those without severe thrombocytopenia (45.0% versus 57.1%, P=0.308). Female gender, older age, and longer course of the disease were independent risk factors for a severe decline in the platelet count.

CONCLUSIONS

A decline in the platelet count and thrombocytopenia are quite common in patients receiving CVVH. The severity of the decline in the platelet count rather than the absolute count during CVVH may be associated with hospital mortality. Knowing the risk factors for a severe decline in the platelet count may allow physicians to prevent such an outcome.

Heparin-Induced Thrombocytopenia: Is There a Role for Direct Thrombin Inhibitors in Therapy?

Heparin is widely used in the intensive care environment usually for thromboprophylaxis but also to facilitate extra-corporeal circuits such as renal replacement and ECMO. Heparin-induced thrombocytopenia (HIT) is a rare but extremely serious disorder. It is associated with significant morbidity and mortality. The diagnosis is often challenging particularly as thrombocytopenia can be caused by a number of other common conditions seen in intensive care. Unfortunately routine screening for HIT antibodies is not helpful as it is possible to have these but have no manifestation of the disease process. If the diagnosis of HIT is not considered and the patient does in fact have the disease process they are at risk of thrombotic episodes. This article reviews the pathophysiology of HIT and the challenges with making the diagnosis. We explore the role of newer anticoagulants that may have a role such as direct thrombin inhibitors.

Development and implementation of a nurse-driven, sliding-scale nomogram for bivalirudin in the management of heparin-induced thrombocytopenia

PURPOSE

A simplified dosing nomogram to assist nurses in adjusting the rate of i.v. bivalirudin administration in cases of heparin-induced thrombocytopenia (HIT) is described.

SUMMARY

To facilitate the availability of bivalirudin [corrected] as an alternative direct thrombin inhibitor (DTI) for patients with HIT at The Ohio State University Wexner Medical Center (OSUWMC), a team of clinical pharmacists developed a nomogram designed to simplify infusion dosage adjustments by nurses. In contrast to bivalirudin nomograms requiring patient-specific, percentage-based dose adjustments, the nomogram developed at OSUWMC specifies fixed adjustments (0.005 or 0.01 mg/kg/hr) according to the current activated partial thromboplastin time (aPTT) value relative to aPTT goals. During pilot testing over three years, the nomogram was used to guide dosage adjustments in 65 adult patients receiving continuous infusions of bivalirudin for suspected or confirmed HIT in intensive care units. Overall, the use of the nomogram resulted in adequate anticoagulation, with 53.7% of all measured aPTT values in the target range; 30.5% of aPTT values were below target, and 15.8% of values were above target. The median time to steady state was 11.0 hours (range, 5.0-31.8 hours), and bleeding rates were consistent with those reported in the literature. Nurse adherence to the nomogram was 100%, and no dosing errors occurred during a total of 487 dosage changes. Based on the pilot study results, the nomogram was refined to improve initial dosing for patients with creatinine clearance values of >30 mL/min; other refinements were made to enhance the safety of bivalirudin therapy for HIT in patients with severe renal impairment.

CONCLUSION

A nurse-driven, sliding-scale nomogram for bivalirudin therapy in patients with HIT provided a simple dosing protocol and resulted in a high rate of adherence by nurses.

Use of argatroban: experiences in continuous renal replacement therapy in critically ill patients after cardiac surgery

OBJECTIVES

Acute kidney injury requiring renal replacement therapy (RRT) is a common complication after cardiac surgery, complicated by suspected or proven heparin-induced thrombocytopenia (type II). The present study evaluated the use of argatroban as an anticoagulant during continuous RRT in the early period after cardiac surgery. Argatroban was compared with unfractionated heparin (UH) with respect to bleeding complications and the effectiveness of anticoagulation.

METHODS

Patients requiring RRT after cardiac surgery from March 2007 to June 2009 were identified. The effectiveness of anticoagulation was measured indirectly by the duration of dialysis filter use. Bleeding was defined as clinical signs of blood loss or the need for transfusion.

RESULTS

Of 94 patients, 41 received argatroban, 27 UH, and 26 required conversion from UH to argatroban. In all 3 subgroups, RRT was begun within a median postoperative period of 2.0 days. Similar levels of anticoagulation were achieved with the duration of the circuit and filter changed an average of 1.1 times daily during RRT. Liver function was comparable in all patients. Neither clinically relevant signs of bleeding nor significant differences in the hemoglobin levels or a requirement for transfusion were noted. However, the Simplified Acute Physiology Score II values during dialysis and mortality were significantly greater in the patients initially receiving argatroban compared with those who received UH alone (54 ± 2 vs 43 ± 3, P < .001; 71% vs 44%, P = .04).

CONCLUSIONS

Argatroban can provide effective anticoagulation in postoperative cardiac patients receiving continuous RRT. Close monitoring and dose titration resulted in a comparable risk of bleeding for anticoagulation with both argatroban and heparin, regardless of the disease severity or impaired hepatic function.

Argatroban in heparin-induced thrombocytopenia: rationale for use and place in therapy

Heparin-induced thrombocytopenia (HIT) is a recognized complication of heparin and requires urgent detection and treatment. HIT can be divided into two types, type I and type II, with type I being a transient decrease in platelet count without clinical consequence. For the purpose of this review, the term HIT refers to the immune-mediated type II that causes paradoxical thrombo-emboli. The aim of this review is to familiarize clinicians with a specific direct thrombin inhibitor, argatroban, in the treatment of HIT. Argatroban has been successfully employed in treating HIT in many different subsets of patients, including those with endstage renal disease on hemodialysis and in patients undergoing percutaneous coronary intervention and those with multiorgan dysfunction syndrome.

Argatroban dose reductions for suspected heparin-induced thrombocytopenia complicated by child-pugh class C liver disease

OBJECTIVE

To report our experience of reduced-dose argatroban in a patient with suspected heparin-induced thrombocytopenia (HIT) and Child-Pugh class C liver disease and review the relevant literature to summarize current recommendations on argatroban use in patients with severe liver disease.

CASE SUMMARY

A 58-year-old male with Child-Pugh class C liver disease (Model for End-Stage Liver Disease [MELD] score = 31, total bilirubin 4.5 mg/dL) and hemodialysis-dependent renal failure was hospitalized with acute deep vein thrombosis (DVT). Three days after heparin initiation for DVT, he developed thrombocytopenia. Given his heparin exposure (both for treatment of DVT and ongoing hemodialysis), HIT was suspected and all heparinoids were immediately discontinued. Argatroban was initiated for the treatment of HIT while laboratory testing for HIT antibodies and the serotonin release assay were completed. Because of the patient's advanced liver disease, the starting dose of argatroban was reduced to 0.2 μg/kg/min, with frequent monitoring of the activated partial thromboplastin time (aPTT) (goal 60-85 seconds). Despite this dose reduction, the aPTT was supratherapeutic. Following further dose reductions, a final argatroban maintenance dose of 0.05 μg/kg/min was necessary for the attainment of goal aPTTs.

DISCUSSION

Reducing the starting dose of argatroban to 0.5 μg/kg/min is recommended in patients with liver disease. Nevertheless, this recommended dose is largely based on data from patients with more moderate liver disease (eg, Child-Pugh class A or B), and dosing in more advanced liver disease remains largely unexplored. Patients with more advanced liver disease may require additional dose reductions to avoid supratherapeutic concentrations of anticoagulation agents and to minimize bleeding risk.

CONCLUSIONS

This report illustrates the importance of careful selection of argatroban dosing and appropriate aPTT monitoring in patients with severe liver disease. Excessive anticoagulation may precipitate major bleeding complications, placing patients with this complicated disease at undue risk.

Safety and Efficacy of Argatroban in the Management of Heparin-Induced Thrombocytopenia

Heparin-induced thrombocytopenia (HIT) is a life-threatening adverse reaction to heparin therapy that is characterized by thrombocytopenia and an increased risk of venous and arterial thrombosis. According to guidelines, in patients with strongly suspected or confirmed HIT all sources of heparin have to be discontinued and an alternative, nonheparin anticoagulant for HIT treatment must immediately be started. For both the prophylaxis of thrombembolic events in HIT and the treatment of HIT with thrombosis the direct thrombin inhibitor argatroban is approved in the United States. The objective of this review is to describe the mechanism of action and the pharmacokinetic profile of argatroban, to characterize argatroban regarding its safety and therapeutic efficacy and to discuss its place in therapy in HIT.

Evaluation of empiric versus nomogram-based direct thrombin inhibitor management in patients with suspected heparin-induced thrombocytopenia

The aim of this study was to evaluate a direct thrombin inhibitor (DTI) titration protocol in patients with suspected HIT. This observational study compared patients treated with argatroban or bivalirudin according to the University of Colorado Hospital DTI titration protocol versus a control group treated prior to protocol implementation. Protocol patients had DTI initial doses based on organ function and fixed dosage adjustments of 10, 25, or 50%. Initial doses and titrations in the control group were made per physician discretion. A total of 130 patients were enrolled: 47 in the protocol group and 83 in the control group (median age 54 years, 63% male, 78% critically ill, and 54% received argatroban). Goal aPTT was achieved with initial DTI dose in 64% of protocol patients and 46% of control patients (P = 0.07). Median (IQR) time to goal aPTT was reduced in the protocol group compared to the control group [5 hr (2-10 hr) vs. 13 hr (6-29 hr); P < 0.0001]. Median time to dose stabilization was 10 hr (6-27 hr) and 22 hr (13-40 hr) in the protocol and control groups, respectively; P < 0.0001. Median number of titrations to goal was 0 (0-1) versus 1 (0-4), respectively; P = 0.02. Median percentage of aPTT values in goal was 67% (41-100%) versus 53% (33-76%), respectively; P = 0.027. The DTI titration protocol shortened time to achieve goal aPTT, reduced time to dose stabilization, decreased the number of titrations required to achieve aPTT goal, and improved the percentage of aPTT values in goal range.