Recombinant Factor VIIa to Manage Major Bleeding from Newer Parenteral Anticoagulants

Updates in Pediatric Extracorporeal Membrane Oxygenation

Extracorporeal membrane oxygenation is an increasingly used mode of life support for patients with cardiac and/or respiratory failure refractory to conventional therapy. This review provides a synopsis of the evolution of extracorporeal life support in neonates, infants, and children and offers a framework for areas in need of research. Specific aspects addressed are the changing epidemiology; technologic advancements in extracorporeal membrane oxygenation circuitry; the current status and future direction of anticoagulation management; sedative and analgesic strategies; and outcomes, with special attention to the lessons learned from neonatal survivors.

Pharmacology of Peripheral Arterial Disease in the Angio Suite: What Every Interventionalist Should Know

Safe and effective treatment of peripheral arterial disease (PAD) and critical limb ischemia can be routinely performed in the angiography suite. A systematic understanding of the medications commonly used during these procedures is essential. This review discusses the traditional roles of the medications used in PAD procedures, the existing evidence basis for those roles, potential alternatives, and evolving techniques. Developing a familiarity with these medications can help improve outcomes and safety for the patients being treated.

Major publications in the critical care pharmacotherapy literature: January-December 2016

PURPOSE

To summarize select critical care pharmacotherapy guidelines and studies published in 2016.

SUMMARY

The Critical Care Pharmacotherapy Literature Update (CCPLU) Group screened 31 journals monthly for relevant pharmacotherapy articles and selected 107 articles for review over the course of 2016. Of those included in the monthly CCPLU, three guidelines and seven primary literature studies are reviewed here. The guideline updates included are as follows: hospital-acquired pneumonia and ventilator-associated pneumonia management, sustained neuromuscular blocking agent use, and reversal of antithrombotics in intracranial hemorrhage (ICH). The primary literature summaries evaluate the following: dexmedetomidine for delirium prevention in post-cardiac surgery, dexmedetomidine for delirium management in mechanically ventilated patients, high-dose epoetin alfa after out-of-hospital cardiac arrest, ideal blood pressure targets in ICH, hydrocortisone in severe sepsis, procalcitonin-guided antibiotic de-escalation, and empiric micafungin therapy.

CONCLUSION

The review provides a synopsis of select pharmacotherapy publications in 2016 applicable to clinical practice.

Bivalirudin for Alternative Anticoagulation in Extracorporeal Membrane Oxygenation: A Systematic Review

Background:

Extracorporeal membrane oxygenation (ECMO) offers therapeutic options in refractory respiratory and/or cardiac failure. Systemic anticoagulation with heparin is routinely administered. However, in patients with heparin-induced thrombocytopenia or heparin resistance, the direct thrombin inhibitor bivalirudin is a valid option and has been increasingly used for ECMO anticoagulation. We aimed at evaluating its safety and its optimal dosing for ECMO.

Methods:

Systematic web-based literature search of PubMed and EMBASE performed via National Health Service Library Evidence and manually, updated until January 30, 2016.

Results:

The search revealed 8 publications relevant to the topic (5 case reports). In total, 58 patients (24 pediatrics) were reported (18 received heparin as control groups). Bivalirudin was used with or without loading dose, followed by infusion at different ranges (lowest 0.1-0.2 mg/kg/h without loading dose; highest 0.5 mg/kg/h after loading dose). The strategies for monitoring anticoagulation and optimal targets were dissimilar (activated partial thromboplastin time 45-60 seconds to 42-88 seconds; activated clotting time 180-200 seconds to 200-220 seconds; thromboelastography in 1 study).

Conclusion:

Bivalirudin loading dose was not always used; infusion range and anticoagulation targets were different. In this systematic review, we discuss the reasons for this variability. Larger studies are needed to establish the optimal approach with the use of bivalirudin for ECMO.

Guidance for the practical management of the heparin anticoagulants in the treatment of venous thromboembolism

Venous thromboembolism (VTE) is a serious and often fatal medical condition with an increasing incidence. Despite the changing landscape of VTE treatment with the introduction of the new direct oral anticoagulants many uncertainties remain regarding the optimal use of traditional parenteral agents. This manuscript, initiated by the Anticoagulation Forum, provides clinical guidance based on existing guidelines and consensus expert opinion where guidelines are lacking. This specific chapter addresses the practical management of heparins including low molecular weight heparins and fondaparinux. For each anticoagulant a list of the most common practice related questions were created. Each question was addressed using a brief focused literature review followed by a multidisciplinary consensus guidance recommendation. Issues addressed included initial anticoagulant dosing recommendations, recommended baseline laboratory monitoring, managing dose adjustments, evidence to support a relationship between laboratory tests and meaningful clinical outcomes, special patient populations including extremes of weight and renal impairment, duration of necessary parenteral therapy during the transition to oral therapy, candidates for outpatient treatment where appropriate and management of over-anticoagulation and adverse effects including bleeding and heparin induced thrombocytopenia. This article concludes with a concise table of clinical management questions and guidance recommendations to provide a quick reference for the practical management of heparin, low molecular weight heparin and fondaparinux.

Effect of activated charcoal on apixaban pharmacokinetics in healthy subjects

Background

Activated charcoal is commonly used to manage overdose or accidental ingestion of medicines. This study evaluated the effect of activated charcoal on apixaban exposure in human subjects.

Methods

This was an open-label, three-treatment, three-period, randomized, crossover study of single-dose apixaban (20 mg) administered alone and with activated charcoal given at 2 or 6 h post-dose to healthy subjects. Blood samples for assay of plasma apixaban concentration were collected up to 72 h post-dose. Pharmacokinetic parameters, including peak plasma concentration (C_max), time to C_max (T_max), area under the concentration–time curve from time 0 to infinity (AUC_INF), and terminal half-life (T_½), were derived from apixaban plasma concentration–time data. A general linear mixed-effect model analysis of C_max and AUC_INF was performed to estimate the effect of activated charcoal on apixaban exposure.

Results

A total of 18 subjects were treated and completed the study. AUC_INF for apixaban without activated charcoal decreased by 50 and 28 %, respectively, when charcoal was administered at 2 and 6 h post-dose. Apixaban C_max and T_max were similar across treatments. The mean T_½ for apixaban alone (13.4 h) decreased to ~5 h when activated charcoal was administered at 2 or 6 h post-dose. Overall, apixaban was well tolerated in this healthy population, and most adverse events were consistent with the known profile of activated charcoal.

Conclusion

Administration of activated charcoal up to 6 h after apixaban reduced apixaban exposure and facilitated the elimination of apixaban. These results suggest that activated charcoal may be useful in the management of apixaban overdose or accidental ingestion.

Bivalirudin in pediatric patients maintained on extracorporeal life support

OBJECTIVE

Anticoagulation with heparin is standard of care for patients maintained on extracorporeal life support. Very limited evidence exists for the use of alternative anticoagulants during extracorporeal life support. Patients with heparin-induced thrombocytopenia, heparin resistance, and evidence of significant thrombosis while on heparin may be candidates for alternative anticoagulation. The objective of this analysis is to present evidence for the use of bivalirudin during extracorporeal life support in pediatric patients.

DESIGN

Case series.

SETTING

University of California, Davis Medical Center.

PATIENTS

Twelve critically ill, pediatric patients receiving bivalirudin for anticoagulation during extracorporeal life support.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Twelve patients meeting entry criteria received bivalirudin during the study period. The median patient age was 8 days (range, 1 d to 6 yr). Eight patients were neonates. Eight patients were male. Nine patients were supported with venoarterial extracorporeal life support. Median duration of extracorporeal life support was 226 hours (range, 111-913) and median time on bivalirudin was 92 hours (range, 60-230). Bivalirudin bolus doses were administered to select patients without bleeding complications. The maintenance dose that corresponded with initial target activated partial thromboplastin time ranged from 0.045 to 0.48 mg/kg/hr with a median rate of 0.16 mg/kg/hr. The median dose for days 1, 3, and 5 was 0.135, 0.175, and 0.267 mg/kg/hr, respectively. The correlation (r2) between dose adjustment and activated partial thromboplastin time response was 0.264.

CONCLUSIONS

This is the largest case series describing the use of a direct thrombin inhibitor in pediatric extracorporeal life support patients. The maintenance dose range reflected considerable inter-patient variability. There was an observed increase in dose requirements with time. Bivalirudin, with close monitoring, is a potential option for pediatric patients on extracorporeal life support who have developed heparin-induced thrombocytopenia, heparin resistance, or significant thrombosis while on heparin.

Correction of coagulopathy for percutaneous interventions

Due to medical illness or pharmacotherapy, patients undergoing percutaneous interventions often have abnormal hemostasis. Its etiology may include alterations in the protein-based coagulation system, thrombocytopenia, deficient platelet function, or mixed deficits such as disseminated intravascular coagulation. In this article, the authors review the basic science of each of these etiologies, as well as their available methods of correction. They also review the evidence and guidelines regarding the assessment and treatment of coagulopathy in image-guided procedures. The periprocedural bleeding risk and the urgency of a given procedure guide the management of abnormal hemostasis in this patient population.

New parenteral anticoagulants in development

The therapeutic armamentarium of parenteral anticoagulants available to clinicians is mainly composed by unfractionated heparin (UFH), low-molecular-weight heparin (LMWH), fondaparinux, recombinant hirudins (i.e. bivalirudin, desirudin, lepirudin) and argatroban. These drugs are effective and safe for prevention and/or treatment of thromboembolic diseases but they have some drawbacks. Among other inconveniences, UFH requires regular anticoagulant monitoring as a result of variability in the anticoagulant response and there is a risk of serious heparin-induced thrombocytopaenia (HIT). LMWH, fondaparinux and recombinant hirudins are mainly cleared through the kidneys and their use in patients with severe renal insufficiency may be problematic. LMWH is only partially neutralized by protamine while fondaparinux and recombinant hirudins have no specific antidote. Novel anticoagulants in development for parenteral administration include new indirect activated factor Xa (FXa) inhibitors (idrabiotaparinux, ultra-low-molecular-weight heparins [semuloparin, RO-14], new LMWH [M118]), direct FXa inhibitors (otamixaban), direct FIIa inhibitors (flovagatran sodium, pegmusirudin, NU172, HD1-22), direct FXIa inhibitors (BMS-262084, antisense oligonucleotides targeting FXIa, clavatadine), direct FIXa inhibitors (RB-006), FVIIIa inhibitors (TB-402), FVIIa/tissue factor inhibitors (tifacogin, NAPc2, PCI-27483, BMS-593214), FVa inhibitors (drotrecogin alpha activated, ART-123) and dual thrombin/FXa inhibitors (EP217609, tanogitran). These new compounds have the potential to complement established parenteral anticoagulants. In the present review, we discuss the pharmacology of new parenteral anticoagulants, the results of clinical studies, the newly planned or ongoing clinical trials with these compounds, and their potential advantages and drawbacks over existing therapies.

Low-Molecular-Weight Heparin Overdose: Management by Observation

Objective:

To describe 3 episodes of low-molecular-weight heparin (LMWH) overdose in 2 patients and discuss the clinical presentations, outcomes, and therapeutic options.

Case Summaries:

The first patient, a 35-year-old female, presented after an intentional overdose of 72,000 units of dalteparin. The peak measured anti-Xa activity was 6.2 U/mL at 7.5 hours postinjection. No interventions were performed and there were no bleeding complications. The patient presented 20 days later following another overdose of 72,000 units. Anti-Xa activity was 4.5 U/mL 2 hours postinjection. No treatment was given and the patient was discharged with plans for follow-up the next day. There was no evidence of bleeding complications on follow-up. The second patient, a 29-year-old male, presented after an intentional overdose of 480 mg of enoxaparin. The anti-Xa activity was 1.9 U/mL measured 2 hours postinjection. The patient was observed without intervention. There were no bleeding complications.

Discussion:

To our knowledge, there is only one previous report of an LMWH overdose in the literature, an iatrogenic overdose in an infant treated with protamine. In our 3 presented episodes of LMWH overdose, no therapeutic interventions were performed and there were no bleeding complications. Review of the literature regarding the efficacy of protamine and recombinant factor VIIa for reversal of LMWH coagulopathy revealed that protamine is only partially effective and recombinant factor VIIa is effective in in vitro studies and case reports.

Conclusions:

In cases of LMWH overdose, observation seems to be appropriate in the absence of clinically significant bleeding. Prolonged monitoring may be necessary for patients with renal failure. Use of protamine or recombinant factor VIIa is not supported by this case series in patients without significant bleeding. There is a lack of data regarding how to treat patients with significant bleeding.