Current State of Knowledge on Oral Anticoagulant Reversal Using Procoagulant Factors

Complications of Dentoalveolar Surgery

This article explores how to prevent and manage complications of dentoalveolar surgery. Many complications are avoidable. Surgical skills and knowledge of anatomy play an important role in prevention of complications. Prevention starts with detailed history and physical examination of the patient. Key to perioperative management of patients is risk assessment. Without a proper history and physical examination, the clinician is unable to assess the risk of performing surgery and anesthesia for each patient. Some illnesses and medications increase the risk of complications. The following complications are discussed: alveolar osteitis, displacement, fracture, hemorrhage, infection, nonhealing wound, oroantral communication, swelling, and trismus.

Rapid Reversal of Novel Anticoagulant and Antiplatelet Medications in General Surgery Emergencies

The reversal of the new class of nonvitamin K antagonist oral anticoagulants (NOACs) is challenging in the emergent perioperative setting. This summary focuses on the reversal of NOACs, determining the emergent nature (risk analysis), and other considerations in reversal.

Management of antithrombotic agents in patients undergoing flexible bronchoscopy

Bleeding is one of the most feared complications of flexible bronchoscopy. Although infrequent, it can be catastrophic and result in fatal outcomes. Compared to other endoscopic procedures, the risk of morbidity and mortality from the bleeding is increased, as even a small amount of blood can fill the tracheobronchial tree and lead to respiratory failure. Patients using antithrombotic agents (ATAs) have higher bleeding risk. A thorough understanding of the different ATAs is critical to manage patients during the peri-procedural period. A decision to stop an ATA before bronchoscopy should take into account a variety of factors, including indication for its use and the type of procedure. This article serves as a detailed review on the different ATAs, their pharmacokinetics and the pre- and post-bronchoscopy management of patients receiving these medications.

Non-Vitamin K Antagonist Oral Anticoagulants: The Clinician's New Challenge

Millions of US patients are prescribed oral anticoagulants. Traditionally, oral anticoagulation was achieved with vitamin K antagonists (VKAs). In recent years, non-VKA oral anticoagulants (NOACs) have emerged that provide an effective and convenient alternative to VKAs. These agents possess very different pharmacologic properties from what the medical community has grown accustom to with the VKAs. Thus, a new knowledge base is required for NOACs. One particular challenge with the NOACs is the lack of specific reversal agent, resulting in difficulties correcting the coagulopathy induced by these drugs when needed. A review of the current literature is presented to assist clinicians in gaining knowledge of the NOACs to care for patients.

Lack of significant bleeding despite large acute rivaroxaban overdose confirmed with whole blood concentrations

BACKGROUND

Since intentional overdose with rivaroxaban is expected to lead to significant coagulopathy and bleeding, prophylactic reversal has been suggested. We report a single massive ingestion confirmed by a blood concentration that was managed with expectant therapy alone.

CASE REPORT

A 71-year-old man with atrial fibrillation, aortic valve replacement, and congestive heart failure presented to the emergency department after an intentional ingestion of 97 (1940 mg total) rivaroxaban tablets in a suicide attempt. Initial laboratories revealed: PT, 60.2 s; INR 7.2; aPTT, 55.7 s; BUN 28 mg/dL; and creatinine 1.2 mg/dL. A whole-blood rivaroxaban concentration obtained on hospital-day three was 160 ng/mL. The patient was admitted for continued observation and the coagulation markers trended downward with no major bleeding events. No reversal agents or blood products were given during his hospitalization.

CONCLUSION

In the setting of a single, acute rivaroxaban overdose, with normal renal function, and no active bleeding, conservative therapy alone may be sufficient.

In vitro reversal of supratherapeutic rivaroxaban levels with coagulation factor concentrates

BACKGROUND

A bleeding patient undergoing therapy with new oral anticoagulants is every clinician's nightmare as no specific reversal agent is available yet. This in vitro study investigated the effect of prothrombin complex concentrate (PCC), recombinant activated factor VII (rFVIIa) and activated prothrombin complex concentrate (aPCC) on supratherapeutic rivaroxaban concentrations using standard laboratory parameters (prothrombin time [PT], activated partial thromboplastin time [aPTT] and PT ratio) and thromboelastometry (clotting time [CT]).

MATERIALS AND METHODS

Blood samples from 10 healthy volunteers were collected and spiked with a supratherapeutic dose of rivaroxaban. Afterwards PCC, rFVIIa and aPCC were added in two doses. The laboratory parameters were measured and thromboelastometry was performed.

RESULTS

The addition of the reversal agents had the following statistically significant effects (all p<0.01): +25 IU/kg PCC: CT -15 s, aPTT +5 s; +50 IU/kg PCC: aPTT +11 s; +90 μg rFVIIa: CT -141 s; +25 IU/kg aPCC: CT -142 s, aPTT -9 s, PT ratio +14%, PT -10.5 s; +50 IU/kg aPCC: CT -118 s, aPTT -7 s, PT ratio +17%, PT -12.2 s.

DISCUSSION

rFVIIa and aPCC, but not PCC, appear to shorten coagulation times significantly in standard laboratory and thromboelastometry assays. These results need confirmation through evaluation of these agents in the clinical setting.

Use of low-dose prothrombin complex concentrate before lumbar puncture

PURPOSE

The use of an off-label dose of four-factor prothrombin complex concentrate (PCC) for International Normalized Ratio (INR) reversal in a patient before a diagnostic lumbar puncture is reported.

SUMMARY

A 57-year-old, 122-kg man arrived at the hospital with a possible diagnosis of meningitis and had an INR of >3 while on warfarin therapy. The patient initiated warfarin therapy in 2009 due to recurrent deep vein thrombosis. The patient required reversal of his elevated INR in order for a lumbar puncture to be safely performed (INR must be no higher than 1.4). Multiple units of fresh frozen plasma (FFP) were administered, with a subsequent INR decrease to 1.9. Additional units of FFP were given. The patient developed respiratory decompensation due to volume overload, partially caused by the administration of multiple units of FFP. As the INR remained above 1.4 but was less than 2, an alternative dosing strategy was used. A dose of 1020 units of factor IX, equaling about 10 mg/kg based on a maximum dosing weight of 100 kg, was administered. The two vials of PCC administered each contained 510 units of factor IX. No vitamin K was given. The patient's INR, checked 30 minutes after PCC administration, was 1.3, and the lumbar puncture was performed. The lumbar puncture was completed without complication, and the patient was restarted on therapeutic anticoagulation the following day.

CONCLUSION

A 57-year-old patient was successfully treated with low-dose PCC to reverse an INR from 1.7 to 1.3 in order to perform a diagnostic lumbar puncture.

Management of apixaban-associated subdural hematoma: a case report on the use of factor eight inhibitor bypassing activity

OBJECTIVE

We report a case of a patient receiving apixaban who developed a spontaneous subdural hematoma and declining mental status that improved after administration of a single dose of factor eight inhibitor bypassing activity.

DESIGN

Case report.

SETTING

Comprehensive Stroke Center, Neurocritical Care Unit.

PATIENT

A 76-year-old man presented to an outside facility with a chief complaint of headache and pain behind his right eye. A CT scan of his head revealed a subdural hematoma. The patient was transferred to our facility with worsening clinical status.

INTERVENTIONS

After a confirmatory cranial CT scan revealed a worsening subdural hematoma with midline shift, a single dose of factor VIII inhibitor bypassing activity (25 U/kg) was administered.

MEASUREMENTS AND MAIN RESULTS

Coagulation tests following the administration of factor VIII inhibitor bypassing activity and a follow-up CT scan confirmed hemostasis. The patient was discharged home with no focal deficits.

CONCLUSIONS

Factor VIII inhibitor bypassing activity may be a viable, nonspecific reversal agent for life-threatening bleeding associated with apixaban.

[Perioperative management of direct oral anticoagulant in emergency surgery and bleeding. Haemostasis monitoring and treatment]

There is an almost unanimous consensus on the management of the direct new oral anticoagulants, dabigatran, rivaroxaban, and apixaban in elective surgery. However, this general consensus does not exist in relation with the direct new oral anticoagulants use in emergency surgery, especially in the bleeding patient. For this reason, a literature review was performed using the MEDLINE-PubMed. An analysis was made of the journal articles, reviews, systematic reviews, and practices guidelines published between 2000 and 2014 using the terms "monitoring" and "reversal". From this review, it was shown that the routine tests of blood coagulation, such as the prothrombin time and activated partial thromboplastin time, have a limited efficacy in the perioperative control of blood coagulation in these patients. There is currently no antidote to reverse the effects of these drugs, although the possibility of using concentrated prothrombin complex and recombinant activated factor vii has been suggested for the urgent reversal of the anticoagulant effect.

Strategies for urgent reversal of target-specific oral anticoagulants

The direct thrombin inhibitor dabigatran and factor Xa inhibitors rivaroxaban and apixaban are US Food and Drug Administration (FDA)-approved target-specific oral anticoagulants (TSOACs) that have emerged onto the market for use in some indications similar to those for warfarin; in addition, edoxaban is seeking FDA approval. Similar indications include reducing the risk of stroke and systemic embolism in patients with nonvalvular atrial fibrillation for all 3 agents, for the prevention of deep vein thrombosis that may lead to pulmonary embolism in patients undergoing hip or knee surgery for rivaroxaban and apixaban, and for the treatment and prevention of deep vein thrombosis and pulmonary embolism. As anticoagulants, they are all associated with a risk of bleeding, and, unfortunately, there are no approved antidotes for reversal of these agents. A number of small studies in human subjects and in human/animal models exposed to TSOACs have evaluated the use of activated charcoal, hemodialysis for dabigatran, or clotting factor concentrates for their ability to neutralize the anticoagulant effects or reduce drug concentrations of TSOACs. Clotting factor concentrates that have been used include prothrombin complex concentrates and recombinant factor VII. This review examines studies and case reports evaluating these strategies for expedited or emergent reversal of TSOACs.

Balancing the risk of complications in foot and ankle surgical patients taking antithrombotic medication

This review intends to provide guidance regarding perioperative management of anticoagulation and antiplatelet drug therapy as they relate to foot and ankle surgery. Venous and arterial thromboembolism are conditions in which the blood clots inappropriately, causing considerable morbidity and mortality. With an increase in awareness of thromboembolic risk factors and expansion of therapeutic options, more patients are routinely taking antithrombotic medication. When these patients require invasive procedures, a decision needs to be made if antithrombotic medication should be held perioperatively and if additional precautions are needed in the interim. Understanding the factors affecting the management of thromboembolism during the perioperative period can reduce the potential for complications.

LEVELS OF EVIDENCE

Therapeutic, Level V: Expert opinion.

Managing a Rivaroxaban Bleed: Understanding the Difficulties in Acute Reversal of the New Oral Anticoagulants through a Case Report

With the arrival of a new generation of oral anticoagulants significant burdens associated with warfarin's use on both the patient and the healthcare system have been alleviated. Nevertheless, a shortfall exists in regard to an agent or protocol for reversal of these new anticoagulants in the setting of an acute bleed. Our case of a patient presenting to the hospital with a vaginal bleed while on rivaroxaban highlights the difficulty in management without a clear protocol or agent for reversal of anticoagulation.

Warfarin versus dabigatran etexilate: an assessment of efficacy and safety in patients with atrial fibrillation

INTRODUCTION

Oral anticoagulation is the mainstay for stroke and thromboembolic event prevention in patients with atrial fibrillation (AF). Given limitations of warfarin therapy, non-vitamin K oral anticoagulants have been developed including direct thrombin inhibitors (i.e., dabigatran etexilate). Dabigatran etexilate has been tested thoroughly in terms of efficacy and safety in clinical trials and studies, involving 'real-world' cohorts. In this review, currently available evidence in patients with non-valvular AF is discussed.

AREAS COVERED

The pharmacology, efficacy and safety, and current aspects of use of dabigatran etexilate in patients with non-valvular AF are reviewed in a comparative manner to warfarin both for chronic anticoagulation and in different clinical settings.

EXPERT OPINION

Dabigatran etexilate appeared to have several pharmacokinetic and pharmacodynamic advantages over warfarin, as well as a favorable efficacy and safety profile being at least noninferior and often superior to warfarin in patients with non-valvular AF. The latter was shown in the clinical trials, meta-analyses and studies with 'real-world' data. Currently ongoing trials will expand the body of evidence on warfarin and will aid decision making in currently controversial areas. Important limitations of dabigatran etexilate include contraindications for its use in patients with prosthetic heart valves and end-stage chronic kidney disease.

Current state of anticoagulants to treat deep venous thrombosis

Anticoagulation remains the cornerstone of treatment in patients with deep vein thrombosis (DVT). While parenteral anticoagulants and oral vitamin K antagonists (e.g., warfarin) have been used for many decades, the recent development of novel oral anticoagulants have provided clinicians with an expanding set of therapeutic options for DVT. This review summarizes the pharmacology and clinical trial results of these new oral anticoagulants. Several practical considerations to the use of these oral anticoagulants including issues related to adherence, monitoring, and reversal are also discussed.

Preoperative evaluation of the vascular surgery patient

Patients undergoing vascular surgery present a myriad of perioperative challenges due to the complex comorbidities affecting them in conjunction with high-risk surgical procedures. Additionally, advances in endovascular technology have enabled surgical procedures to be performed on patients who would not have been considered surgical candidates in the past. This combination of increasing patient morbidity and evolving surgical technique requires a well-planned preoperative assessment and close communication with surgical and perioperative colleagues. This article outlines an appropriate approach by first considering each organ system, followed by review of considerations unique to various surgical procedures, and then an overall assessment of risk.

Managing new oral anticoagulants in the intensive care unit

Warfarin has been the mainstay of oral anticoagulation for more than half a century. Within the last several years, 2 new classes of oral anticoagulants have been introduced as potential alternatives to warfarin for certain indications. The oral direct thrombin inhibitor, dabigatran, and 2 factor Xa inhibitors, rivaroxaban and apixaban, are the newest agents approved for use in the United States. These agents have been studied in various areas including stroke prophylaxis in atrial fibrillation, prevention and treatment of venous thromboembolism, and for reduction of ischemic events following acute coronary syndromes. While these agents do not require routine monitoring of international normalized ratio, these agents may be more challenging to reverse than traditional warfarin therapy. The following review will focus on describing the areas where the new oral anticoagulant agents have been studied, the basic pharmacologic characteristics of each agent, and how to appropriately manage the reversal of these agents when indicated.

The role of prothrombin complex concentrates in reversal of target specific anticoagulants

Over the past several years a new era for patients requiring anticoagulation has arrived. The approval of new target specific oral anticoagulants offers practitioners several advantages over traditionally used vitamin K antagonist agents including predictable pharmacokinetics, rapid onset of action, comparable efficacy and safety, all without the need for routine monitoring. Despite these benefits, hemorrhagic complicates are inevitable with any anticoagulation treatment. One of the major disadvantages of the new oral anticoagulants is lack of specific antidotes or reversal agents for patients with serious bleeding or need for urgent surgery. As use of the new target specific oral anticoagulants continues to increase, practitioners will need to understand both the pharmacodynamics and pharmacokinetic properties of the agents, as well as, the available literature with use of non-specific therapies to reverse anticoagulation. Four factor prothrombin complex concentrates have been available for several years in Europe, and recently became available in the United States with approval of Kcentra. These products have shown efficacy in reversing anticoagulation from vitamin K antagonists, however their usefulness with the new target specific oral anticoagulants is poorly understood. This article will review the properties of dabigatran, rivaroxaban and apixaban, as well as the limited literature available on the effectiveness of prothrombin complex concentrates in reversal of their anticoagulant effects. Additional studies are needed to more accurately define the role of prothrombin complex concentrates in patients with life threatening bleeding or who require emergent surgery, as current data is both limited and conflicting.

New oral anticoagulants and oculoplastic surgery

The use of oral anticoagulants is increasing because of the rising prevalence of atrial fibrillation and other cardiovascular diseases that occur in an aging population. In the last decade, several new oral anticoagulants have emerged, comprising the direct thrombin inhibitor dabigatran and the factor Xa inhibitors apixaban and rivaroxaban. Although these new anticoagulants may not affect clear corneal cataract surgery, their use will impact the management of patients having eyelid, orbital, and nasolacrimal procedures. The objective of this review is to provide a concise and practical approach to the perioperative management of patients who require an oculoplastic procedure and are receiving these new anticoagulants.

Evaluation of dabigatran exposures reported to poison control centers

BACKGROUND

Dabigatran is a novel oral anticoagulant for which a well-defined range of toxicity and proven antidote has not been established.

OBJECTIVE

The primary objective of this study was to characterize dabigatran exposures reported to poison centers by dose ingested, clinical effects, treatments used, and managment sites to gain a better understanding of patient outcomes.

METHODS

A retrospective database review was conducted for dabigatran exposures reported to the National Poison Data System for the American Association of Poison Control Centers (AAPCC) over the period October 2010 to December 2012.

RESULTS

There were 802 human dabigatran exposures involving adults predominantly (91% of cases). Exposure chronicity was acute in 43%, acute-on-chronic in 46%, and chronic in 11%, with the most common reason for an exposure call being an unintentional therapeutic error (70.6%). The most common management sites were on-site in 72% of cases and within a health care facility for 26%. Bleeding events and coagulopathies were the most commonly observed clinical effects. Treatments administered included activated charcoal, blood and coagulation products, hemodialysis, and supportive measures. Confirmed outcomes included death in 13 patients (1.6%), major effects in 23 (2.9%), and moderate effects in 50 (6.2%). More severe outcomes were significantly associated with adverse drug reactions, patients ≥65 years of age, those treated with blood and coagulation products and/or dialysis, and renal dysfunction (P < .05). Children experienced few moderate effects and no major effects or deaths.

CONCLUSIONS

Severe outcomes from dabigatran exposures were not common, occurring in approximately 5% of cases.