Permanent Non-valvular Atrial Fibrillation Research Articles

Anticoagulación oral en la fibrilación auricular no valvular: ¿son efectivas y seguras las recomendaciones científicas en la práctica clínica diaria?

To study the efficacy and safety of an oral anticoagulation protocol for the treatment of nonvalvular atrial fibrillation, based on scientific associations' recommendations, in unselected patients seen in daily clinical practice. The study included all consecutive patients with permanent nonvalvular atrial fibrillation who attended two outpatient cardiology clinics between February 1, 2000 and February 1, 2002. They were treated according to an anticoagulation protocol based on Spanish Society of Cardiology and American College of Cardiology/American Heart Association/European Society of Cardiology guidelines. Patients were followed up prospectively for major events, such as death, stroke, transient ischemic attack, peripheral embolism and severe hemorrhage, which were recorded by treatment group. A total of 624 patients were included in the study. Those receiving anticoagulation therapy (n=425; 68%) more frequently had hypertension, diabetes and previous embolism as well as a greater number of cardioembolic risk factors (P< .001). Overall, 93% of non-anticoagulated patients received platelet aggregation inhibitors (92% received aspirin). After a median follow-up of 21 months, the probability of an embolic event was lower in anticoagulated patients (0.81% vs 14.04%; P< .001), as was all-cause mortality (3.27% vs 6.42%; P=.003). However, there was no significant difference in the probability of severe bleeding (2.75% vs 2.93%; P=.96). Results were unchanged after adjustment for age, sex, and previous embolic events. Oral anticoagulation therapy for nonvalvular atrial fibrillation implemented according to scientific associations' recommendations is effective and safe in daily clinical practice.

Effects of the Oral Direct Thrombin Inhibitor Ximelagatran on P-Selectin Expression and Thrombin Generation in Atrial Fibrillation

This study investigated the pharmacodynamic effects of the oral direct thrombin inhibitor ximelagatran on platelet activation and thrombin generation in patients with nonvalvular atrial fibrillation. Using an open, group-matched study design, the effects of ximelagatran (36 mg twice daily for 5 days) were studied in 12 patients with permanent nonvalvular atrial fibrillation and in 12 healthy controls. After ximelagatran for 5 days, elevated platelet P-selectin expression in atrial fibrillation patients was lowered to that during coumarin treatment or in controls but had no effect in control subjects. Using the endogenous thrombin potential as a marker, ximelagatran decreased and delayed thrombin generation in both groups. In conclusion, direct thrombin inhibition with ximelagatran reduced elevated platelet P-selectin expression and inhibited thrombin generation.