Novel oral anticoagulants in plastic surgery

Novel oral anticoagulants (NOACs) have emerged as a good alternative to warfarin in the prevention of stroke for patients with atrial fibrillation. NOAC use is increasing rapidly; therefore, greater understanding of their use in the perioperative period is important for optimal care. Studies and reviews that reported on the use of NOACs were identified, with particular focus on the perioperative period. PubMed was searched for relevant articles published between January 2000 and August 2015. The inevitable rise in the use of NOACs such as rivaroxaban (Xarelto™), apixaban (Eliquis™), edoxaban (Lixiana™) and dabigatran (Pradaxa™) may present a simplified approach to perioperative anticoagulant management due to fewer drug interactions, rapidity of onset of action and relatively short half-lives. Coagulation status, however, cannot reliably be monitored and no antidotes are currently available. When planning for discontinuation of NOACs, special consideration of renal function is required. Advice regarding the management of bleeding complications is provided for consideration in emergency surgery. In extreme circumstances, haemodialysis may be considered for bleeding with the use of dabigatran. NOACs will increasingly affect operative planning in plastic surgery. In order to reduce the incidence of complications associated with anticoagulation, the management of NOACs in the perioperative period requires knowledge of the time of last dose, renal function and the bleeding risk of the planned procedure. Consideration of these factors will allow appropriate interpretation of the current guidelines.

[Companion Diagnostics for Thrombotic Disease]

In recent years, thrombotic disease, including myocardial infarction and ischemic stroke, has rapidly increased in Japan. To treat and prevent thromboembolism, warfarin has been commonly prescribed for a long period as an oral anticoagulant. However, it is difficult to define an appropriate warfarin dose because of large inter-individual variability in dose requirements and the narrow therapeutic range. Recent pharmacogenomic (PGx) studies have shown that several single nucleotide polymorphisms (SNPs) in CYP2C9 (warfarin metabolic enzyme) and VKORC1 (warfarin target enzyme) are responsible for an individual's warfarin sensitivity. In order to realize personalized warfarin treatment, algorithms to estimate the required warfarin dose based on PGx are under consideration, including the cost-effectiveness. Recently, novel oral anticoagulants (NOACs; dabigatran, rivaroxaban, apixaban, and edoxaban) have become available as well as alternatives to warfarin treatment for the prevention of ischemic stroke in non-valvular atrial fibrillation. Although NOACs are prescribed at a fixed-dose without frequent monitoring of blood coagulability, it has been reported that there is inter-individual variability in the blood concentration of dabigatran caused by gene polymorphisms. Further studies are needed to perform more effective and safer anticoagulant therapy using NOACs. Progress in PGx studies and the realization of personalized anticoagulant therapy are expected in the future. [Review].