Rohan Subasinghe

Non valvular aF increases with age from 0.5 % at age 50-59 to 9 % at age 80-89AF is an independent Risk factor for CVAPatients with AF have a 5 fold mean increase in Stroke due to atrial thrombosis.Stroke mortality is higher in aptients with AF

Aspirin - irreversibly blocks the formation of thromboxane A2 in platelets, producing an inhibitory effect on platelet aggregation

Warfarin - Warfarin inhibits the vitamin K-dependent synthesis of biologically active forms of the calcium-dependent clotting factors II, VII, IX and X

ximelagatran - direct thrombin inhibitor less monitoring required but increased ALT levels

Risk stratification of patients aspirin or warfarin?Possibility of intra and extra cranial haemorrhages.Interaction with other medicationsDisability, cognitive impairment, and problems with compliance are common in the elderly patients with AFInconvenience of monitoring in warfarin therapy and impact on quality of life

http://www.nice.org.uk/nicemedia/pdf/CG036quickrefguide.pdf

Numerous RCTs support tnromboprophylaxis in non valvular AF patients

Meta-analysis: Antithrombotic Therapy to Prevent Stroke in Patients Who Have Nonvalvular Atrial Fibrillation Robert G. Hart, MD; Lesly A. Pearce, MS; and Maria I. Aguilar, MD

To characterize the efficacy and safety of antithrombotic agents for stroke prevention in patients who have atrial fibrillation Adding 13 recent randomized trials to a previous meta-analysis.

Double Blind Randomised trials Mean follow-up of 3 months or longer that tested Antithrombotic agents in patients who have nonvalvular atrial fibrillation.

Data Extraction: Two coauthors independently extracted information regarding interventions; participants; and occurrences of ischemic and hemorrhagic stroke, major extracranial bleeding, and death.

Twenty-nine trials included 28 044 participantsMean age, 71 years; mean follow-up, 1.5 years). Compared with the control, adjusted-dose warfarin (6 trials, 2900 participants) reduced stroke by 64% (95% CI, 49% to 74%) NNT 37 primary 12 secondary prevAntiplatelet agents (8 trials, 4876 participants) reduced stroke by 22% (CI, 6% to 35%). NNT 125 / 40Adjusted-dose warfarin was substantially more efficacious than antiplatelet therapy (relative risk reduction, 39% [CI, 22% to 52%]) (12 trials, 12 963 participants). Heterogeneous NNT not calculable (estimated at 24)

HarmsOther randomized comparisons were inconclusive. Absolute increases in major extracranial haemorrhage were small (0.3% per year) on the basis of metaanalysis. NNH for major haemorrhage 250NNT for mortality benefit 200

Comment BMJ 1992 305 p1460-5 Sordercoat et al

Comment Meta-analysisBearing in mind that AF prevalence increases with age is a mean age of 71 in the trials representative of patients we see?