Monitoring target specific anticoagulants

[Monitoring of NOAC]

BACKGROUND

Monitoring non-vitamin K antagonist oral anticoagulants (NOAC) is usually not necessary; however, in some patients it may prove beneficial.

OBJECTIVES

Patient subgroups who may profit from monitoring were identified, and methods of monitoring (including assessment of which coagulation parameters are affected by NOAC) are described.

MATERIALS AND METHODS

We searched the PubMed database for each of the search terms, "NOAC", "DOAC", "rivaroxaban", "dabigatran", and "apixaban", in combination with one of the terms, "monitoring", "measurement", "measuring", or "assessment". The results were compiled and reviewed.

RESULTS

Monitoring is most advantageous in emergency cases with severe bleeding where drug activity needs to be assessed. It can also help in deciding for or against lysis therapy after acute stroke in patients taking NOAC. Furthermore, it can also identify compliance problems and help in planning periprocedural management. There are quantitative measurement methods which measure plasma concentrations exactly and qualitative methods which only allow for a rough estimate or a general confirmation of drug activity. Recommended quantitative measurement methods are diluted thrombin time for dabigatran, and anti-factor Xa activity (calibrated) for rivaroxaban and apixaban.

CONCLUSIONS

Several patient subgroups may profit from monitoring of NOAC plasma concentration. One should, however, take several issues into consideration before measurements, such as the objective of each individual measurement, possible consequences (e. g., dose adjustment), and which measurement method to pick.

Spontaneous Intracerebral Hemorrhage: Management

Spontaneous non-traumatic intracerebral hemorrhage (ICH) remains a significant cause of mortality and morbidity throughout the world. To improve the devastating course of ICH, various clinical trials for medical and surgical interventions have been conducted in the last 10 years. Recent large-scale clinical trials have reported that early intensive blood pressure reduction can be a safe and feasible strategy for ICH, and have suggested a safe target range for systolic blood pressure. While new medical therapies associated with warfarin and non-vitamin K antagonist oral anticoagulants have been developed to treat ICH, recent trials have not been able to demonstrate the overall beneficial effects of surgical intervention on mortality and functional outcomes. However, some patients with ICH may benefit from surgical management in specific clinical contexts and/or at specific times. Furthermore, clinical trials for minimally invasive surgical evacuation methods are ongoing and may provide positive evidence. Upon understanding the current guidelines for the management of ICH, clinicians can administer appropriate treatment and attempt to improve the clinical outcome of ICH. The purpose of this review is to help in the decision-making of the medical and surgical management of ICH.

Managing bleeding and emergency reversal of newer oral anticoagulants: a review for primary care providers

The therapeutic landscape for anticoagulation management is undergoing a shift from the use of traditional anticlotting agents such as heparins and warfarin as the only options to the growing adoption of newer target-specific oral anticoagulants (TSOACs) with novel mechanisms of action. Dabigatran, the first TSOAC approved for use in the United States, is a direct competitive inhibitor of thrombin. It has predictable kinetics, with an elimination half-life of 12 to 17 hours in healthy volunteers. Apixaban and rivaroxaban are selective inhibitors of factor Xa, and also display first-order kinetics. In younger healthy individuals, apixaban has an apparent half-life of approximately 12 hours, whereas rivaroxaban has an elimination half-life of 5 to 9 hours. Understanding the pharmacologic properties of these newer drugs can lead to better insights regarding their respective safety and efficacy profiles and their application in clinical practice. Laboratory assessments have been developed to measure the anticoagulant efficacy of these newer agents. However, the results of these tests can be highly variable, and are therefore not always useful for monitoring the anticoagulation effects of these agents. In addition, several strategies have been documented for the potential reversal of the anticoagulant effects of these drugs, from the temporary discontinuation of an agent before elective surgery to suggested emergency procedures in the case of major bleeding events. New, specific reversal agents for dabigatran, apixaban, and rivaroxaban are currently being developed, and dabigatran has received fast-track designation from the US Food and Drug Administration. Until comprehensive clinical guidelines are developed, institutions involved in emergency care should establish their own procedures for the management of patients undergoing anticoagulation who require emergency treatment. These protocols should include appropriate laboratory testing to assess anticoagulant activity as part of the inpatient workup if time allows, and the potential use of hemodialysis, prohemostatic agents, and reversal agents when available.

New oral anticoagulants and the cancer patient

Indications for anticoagulation are common in patients with malignancy. Cancer patients have an increased risk of developing venous thromboembolic events or may have other indications for anticoagulation, such as atrial fibrillation. New oral anticoagulants (NOACs) are now available that offer increased options for anticoagulation beyond the traditional vitamin K antagonists and low molecular weight heparins that have long been the cornerstone of treatment. This review will focus on the three NOACs that are currently approved for use in the U.S.: the direct thrombin inhibitor, dabigatran, and the factor Xa inhibitors, apixaban and rivaroxaban. Oncologists are likely to encounter an increasing number of patients taking these agents at the time of their cancer diagnosis or to have patients who develop indications for anticoagulation during the course of their disease. The basic pharmacology, current clinical indications, and approach to the use of NOACs in the cancer patient will be reviewed.