Anticoagulation Reversal

Resuscitation and Preparation of the Emergency General Surgery Patient

Traditionally, the workflow surrounding a general surgery patient allows for a period of evaluation and optimization of underlying medical issues to allow for risk modification; however, in the emergency, this optimization period is largely condensed because of its time-dependent nature. Because the lack of optimization can lead to complications, the ability to rapidly resuscitate the patient, proceed to procedural intervention to control the situation, and manage common medical comorbidities is paramount. This article provides an overview on these subjects.

Coagulopathy and Emergent Reversal of Anticoagulation

More patients than ever are presenting for urgent or emergent procedures while therapeutically anticoagulated for various medical indications. Medications including warfarin, antiplatelet agents such as clopidogrel, direct oral anticoagulants such as apixaban, and even heparin or heparinoids may be present. Each of these medication classes presents its own challenges when coagulopathy needs to be quickly corrected. This review article presents evidence-based discussions of monitoring and reversal of these medication-induced coagulopathies. In addition, there will be a brief discussion of other potential coagulopathies that may be encountered in providing acute care anesthesia.

Bleeding on oral anticoagulants: overview of reversal strategies

Oral anticoagulants (antivitamin K, direct oral anticoagulants) are routinely prescribed for the prevention or treatment of thromboembolic events, and many patients are now on long-term anticoagulant therapy. However, this complicates the management of urgent surgical conditions or major bleeding. Various strategies have been developed to reverse the anticoagulant effect and this narrative review provides an overview of the wide range of therapies currently available.

Pediatric Perioperative Clinical Pharmacy Practice: Clinical Considerations and Management: An Opinion of the Pediatrics and Perioperative Care Practice and Research Networks of the American College of Clinical Pharmacy

Pediatric perioperative clinical pharmacists are uniquely positioned to provide therapeutic and medication management expertise at a particularly vulnerable transition of care from the preoperative space, through surgery, and postoperative setting. There are many direct-patient care activities that are included in the role of the pediatric perioperative pharmacist, as well as many opportunities to develop effective, optimized, and safe medication use processes. This article outlines many of the areas in which a pediatric perioperative clinical pharmacist may intervene.

Systemic Anticoagulation and Reversal

An increasing number of patients are on anticoagulation for a variety of indications. Patients on anticoagulation who present to the hospital with life-threatening hemorrhage, whether trauma related or not, must be assessed for the reversal of anticoagulation. Identification of the type of anticoagulation, the timing of the most recent usage of anticoagulation, and the efficacy of the anticoagulation all have an impact on whether reversal agents should be used. There are a variety of reversal agents, both nonspecific and specific, that could be used for reversal; however, not all reversal agents work for all anticoagulation medication. As more anticoagulation medications are used and indications expand, providers must be aware of the reversal agents available and the efficacy and indications for these reversal agents.

The rebirth of the contact pathway: a new therapeutic target

PURPOSE OF REVIEW

Anticoagulation with vitamin-K antagonists or direct oral anticoagulants is associated with a significant risk of bleeding. There is a major effort underway to develop antithrombotic drugs that have a smaller impact on hemostasis. The plasma contact proteins factor XI (FXI) and factor XII (FXII) have drawn considerable interest because they contribute to thrombosis but have limited roles in hemostasis. Here, we discuss results of preclinical and clinical trials supporting the hypothesis that the contact system contributes to thromboembolic disease.

RECENT FINDINGS

Numerous compounds targeting FXI or FXII have shown antithrombotic properties in preclinical studies. In phase 2 studies, drugs-targeting FXI or its protease form FXIa compared favorably with standard care for venous thrombosis prophylaxis in patients undergoing knee replacement. While less work has been done with FXII inhibitors, they may be particularly useful for limiting thrombosis in situations where blood comes into contact with artificial surfaces of medical devices.

SUMMARY

Inhibitors of contact activation, and particularly of FXI, are showing promise for prevention of thromboembolic disease. Larger studies are required to establish their efficacy, and to establish that they are safer than current therapy from a bleeding standpoint.

Use of Oral Anticoagulation and Diabetes Do Not Inhibit the Angiogenic Potential of Hypoxia Preconditioned Blood-Derived Secretomes

Patients suffering from tissue ischemia, who would greatly benefit from angiogenesis-promoting therapies such as hypoxia preconditioned blood-derived secretomes commonly receive oral anticoagulation (OA) and/or have diabetes mellitus (DM). In this study, we investigated the effect of OA administration on the in vitro angiogenic potential of hypoxia preconditioned plasma (HPP) and serum (HPS), prepared from nondiabetic/diabetic subjects who did not receive OA (n = 5) or were treated with acetylsalicylic acid (ASA, n = 8), ASA + clopidogrel (n = 10), or nonvitamin K antagonist oral anticoagulants (n = 7) for longer than six months. The effect of DM was differentially assessed by comparing HPP/HPS obtained from nondiabetic (n = 8) and diabetic (n = 16) subjects who had not received OA in the past six months. The concentration of key proangiogenic (vascular endothelial growth factor or VEGF) and antiangiogenic (thrombospondin-1 or TSP-1 and platelet factor-4 or PF-4) protein factors in HPP/HPS was analyzed via ELISA, while their ability to induce microvessel formations was examined in endothelial cell cultures. We found that OA use significantly reduced VEGF levels in HPP, but not HPS, compared to non-OA controls. While HPP and HPS TSP-1 levels remained largely unchanged as a result of OA usage, HPS PF-4 levels were significantly reduced in samples obtained from OA-treated subjects. Neither OA administration nor DM appeared to significantly reduce the ability of HPP or HPS to induce microvessel formations in vitro. These findings indicate that OA administration does not limit the angiogenic potential of hypoxia preconditioned blood-derived secretomes, and therefore, it does not prohibit the application of these therapies for supporting tissue vascularization and wound healing in healthy or diabetic subjects.

Utilization of 4-Factor Prothrombin Complex Concentrate for Reversal of Oral Factor Xa Inhibitor-Associated Acute Major Bleeding: A Case Series

OBJECTIVE

In cases of oral factor Xa (FXa) inhibitor-associated acute major bleeding, several reversal strategies are available. Current guidelines recommend a dose of 50 U/kg if using 4-factor prothrombin complex concentrate (4F-PCC). A paucity of data exists with the use of 4F-PCC for FXa inhibitor reversal for acute major bleeding, specifically the most efficacious dosing regimens and safety data. The purpose of this case series is to describe the utilization of 4F-PCC for reversal of oral FXa inhibitor-associated acute major bleeding.

METHODS

This retrospective case series included all admitted patients 18 years and older who received 4F-PCC for oral FXa inhibitor-associated major bleeding. Major bleeding was defined using the International Society of Thrombosis and Hemostasis definition for major bleeding in nonsurgical patients. The primary outcome was achievement of hemostasis.

RESULTS

A total of 31 patients met inclusion criteria, with 17 receiving rivaroxaban and 14 receiving apixaban. Intracranial hemorrhage was the most common type of bleeding occurring in 15 (55%) patients. The median dose of 4F-PCC was 37 U/kg. Of the patients evaluated in the primary end point analysis, 68% achieved effective hemostasis. Four (12.9%) patients experienced a documented thrombotic event within 7 days of receiving 4F-PCC.

CONCLUSION

The use of 4F-PCC for FXa inhibitor-associated acute major bleeding was effective for the majority of patients. The rate of thrombotic events appears higher compared to previously published studies, although major confounders exist and larger studies are needed to fully evaluate the safety of 4F-PCC for this indication.

Unusual presentation of haemoptysis following accidental inhalation of the 'superwarfarin' rodenticide brodifacoum

Haemoptysis is a worrying symptom for patients and can represent a diagnostic challenge for clinicians. We present the case of a 56-year-old woman who presented to the emergency department with acute haemoptysis and associated sudden-onset dyspnoea. The patient remained haemodynamically stable and there was no demonstrable drop in haemoglobin concentration. Following rigorous investigations, on further questioning, the patient recalled inadvertent inhalation of the rodenticide brodifacoum. This exposure was deemed to represent the cause of their acute haemoptysis, which subsequently fully resolved without intervention.

Thrombolysis Following Heparin Reversal With Protamine Sulfate in Acute Ischemic Stroke: Case Series and Literature Review

INTRODUCTION

Administering intravenous IV tissue plasminogen activator (tPA) is the recommended standard of care in acute ischemic stroke (AIS), although it is not recommended to administer intravenous thrombolysis with tPA following heparin reversal with protamine sulfate in patients with AIS.

METHODS

We describe a case series of three patients and the most comprehensive literature review published to date in this specific subset of AIS patients undergoing thrombolysis following heparin reversal with protamine sulfate. The literature review was based on a scoping review methodology performed on four databases; PubMed, CINAHL, Web of Science, and Cochrane Library. All sources were searched from the inauguration of the database until February 2019. A total of six articles involving eight patients were identified.

RESULTS

The primary safety outcome of no symptomatic intracranial hemorrhage (sICH) was met in all eleven patients, although only seven cases had a good functional outcome at 3 months.

CONCLUSIONS

In appropriately selected AIS patients, coagulopathy correction appears to be safe from an sICH standpoint and may be beneficial. However, given the potential for bias with observational databases, case reports and case series, extreme caution is warranted in applying these results to routine clinical practice.

Spontaneous spinal subdural haematoma in a patient on apixaban

A 68-year-old man on apixaban presented to the emergency department with back pain following a long-haul flight. Investigations for pulmonary embolus and aortic dissection were negative and he was discharged with analgesia for mechanical back pain. He presented three more times with worsening back pain, third time with urinary retention and the fourth time with lower limb weakness and loss of coordination. He was found to have a spinal subdural haematoma on MRI and transferred to a tertiary centre, where he was managed conservatively and discharged for rehabilitation with good neurological recovery.