[Preventing cerebrovascular accidents during atrial fibrillation]

Edoxaban: a new oral direct factor xa inhibitor

Edoxaban is an oral direct factor Xa inhibitor that is currently undergoing investigation in phase III clinical trials for the prevention of stroke in patients with atrial fibrillation (AF) and for the prevention and treatment of venous thromboembolic events (VTE). Factor Xa is an attractive target for anticoagulant treatment, as it is the primary and rate-limiting source of amplification in the coagulation cascade. Edoxaban is a competitive inhibitor of factor Xa and has >10 000-fold greater selectivity for factor Xa relative to thrombin. In phase I clinical trials, the anticoagulant effects of edoxaban included dose-dependent increases in activated partial thromboplastin time and prothrombin time following single edoxaban doses of 10-150 mg and after multiple ascending doses (60 mg twice daily, 90 mg daily and 120 mg daily). The anticoagulant effects of edoxaban were rapid in onset (time to peak plasma concentration 1-2 hours) and sustained for up to 24 hours. Prolongation of bleeding time in 8% of subjects was >9.5 minutes (none of which appeared to be clinically significant) 2 hours after initial dosing, and was independent of edoxaban dose, formulation or dietary state. In general, plasma edoxaban concentrations were linearly correlated with coagulation parameters. Phase II clinical trials in patients with AF and VTE suggest that the edoxaban 30 mg once-daily and 60 mg once-daily regimens had a similar or better safety profile compared with dose-adjusted warfarin (international normalized ratio 2.0-3.0) in terms of bleeding events, and that edoxaban was not associated with hepatotoxicity. In addition, edoxaban was associated with statistically significant dose-dependent reductions in VTE after orthopaedic surgery compared with placebo or dalteparin sodium. Further clinical investigation of the efficacy and safety of once-daily edoxaban is being conducted in phase III clinical trials in comparison with warfarin in patients with AF in the phase III ENGAGE AF-TIMI 48 trial (NCT00781391), and in comparison with low-molecular weight heparin/warfarin in the prevention of recurrent VTE in patients with symptomatic deep vein thrombosis and/or pulmonary embolism in the HOKUSAI VTE trial (NCT00986154).

A written policy increases compliance with guidelines for therapeutic anticoagulation prior to elective direct current cardioversion of atrial fibrillation

BACKGROUND

Therapeutic anticoagulation before elective direct current cardioversion (DCC) of atrial fibrillation reduces the risk of embolic stroke. Direct current cardioversion is performed by a variety of practitioners, and variable adherence to preprocedural anticoagulation guidelines is common.

OBJECTIVE

We assessed the impact of a written policy on guideline compliance.

METHODS

: Anticoagulation status and transesophageal echocardiogram (TEE) results were reviewed in 55 patients (32 men/23 women; ages 18-83 years) who underwent elective DCC during the 6-month period before a written anticoagulation policy was sent to physicians who perform, prepare, or refer patients for this procedure. The nurse assigned to each DCC was responsible for documenting anticoagulation status. In accordance with guidelines, therapeutic anticoagulation was defined as a normalized ratio range > or = 2.0 for at least 3 weeks or a negative TEE with a normalized ratio range > or = 2.0 or a partial thromboplastin time > 50 seconds at the time of DCC. Immediately after policy implementation, anticoagulation status and TEE results were reviewed in 53 patients (42 men/11 women; ages 21-84 years) and 1 year post-policy implementation.

RESULTS

Before policy implementation, 14 of 52 patients (27%) had DCC performed without adequate anticoagulation or a negative TEE. Immediately postimplementation, only 2 of 50 patients (4%) had DCC performed without adequate anticoagulation or a negative TEE (P = .002). One year post-policy implementation, only 4 of 48 patients (8%) had DCC performed without adequate anticoagulation or a negative TEE (P = .03).

CONCLUSIONS

Implementing a written policy greatly reduces the number of patients undergoing DCC without adequate anticoagulation or a negative TEE. The impact of this intervention was quickly demonstrable and persisted during follow-up. Supplementing published recommendations with guideline-driven policies may reduce variations in clinical practice and improve quality of care.

Stroke prevention in diabetes and obesity

Stroke is an important cause of morbidity and mortality, and is an economic burden. Diabetes and obesity are two important modifiable risk factors for stroke. Patients with diabetes have a higher incidence of stroke and a poorer prognosis after stroke. Risk-factor modification is the most important aspect of prevention of stroke in diabetes and obesity. This includes lifestyle modifications and different therapeutic modalities to control conditions, such as diabetes, hypertension, dyslipidemia and arrhythmia. Recent landmark studies have shown the beneficial effects of statins in diabetic patients even with close to normal or normal low-density lipoprotein cholesterol. Obesity, which is a risk factor for diabetes, hypertension and hyperlipidemia has been shown to be an independent risk factor for stroke. Increased leptin, dysregulation of adipocyte proteins, increased insulin resistance and C-reactive protein may be factors involved in the increased incidence of cardiovascular morbidity and mortality directly related to obesity. Visceral fat is a much bigger health risk than subcutaneous fat. Lifestyle interventions and pharmacotherapeutic agents have been used to manage obesity. In morbidly obese patients, surgical intervention seems to be the best method of treatment with a long-lasting favorable metabolic outcome. In the 21st Century, with the advanced medical knowledge and the therapeutic modalities available, it should be possible to reduce the incidence of stroke associated with diabetes and obesity.