Atrial Fibrillation, Aspirin, Antikoagulation - AFASAK

Description:

Warfarin, aspirin, or placebo for thromboembolic events in atrial fibrillation.

Hypothesis:

Anticoagulation therapy with warfarin sodium, as compared with aspirin and placebo, could reduce the incidence of thromboembolism in patients with chronic AF.

Study Design

Study Design:

Patients Screened: 2,546
Patients Enrolled: 1,007
Mean Follow Up: 2 years
Mean Patient Age: 74.2
Female: 46

Patient Populations:

Chronic non-rheumatic AF

Exclusions:

Previous anticoagulation therapy for more than 6 months
Cerebrovascular event within the past month
Contraindications for aspirin/warfarin therapy
Previous side-effects of aspirin/warfarin
Current treatment with aspirin/warfarin
Pregnancy or breast-feeding
Persistent blood pressure above 180/100 mm Hg
Psychiatric diseases, including chronic alcoholism
Heart surgery with valve replacement
Sinus rhythm
Rheumatic heart disease
Refusal to participate.

Primary Endpoints:

Thromboembolic complication (stroke, transient cerebral ischemic attack; or embolic complications to the viscera and extremities).

Secondary Endpoints:

Death

Drug/Procedures Used:

Aspirin 75 mg qd
Warfarin; required dosage assessed by means of "Normotest" with a therapeutic range of 4.2-2.8 international normalized ratio (INR).

Principal Findings:

The incidence of thromboembolic complications and vascular mortality were significantly lower in the warfarin group than in the aspirin and placebo groups, which did not differ significantly from each other. 5 patients on warfarin had thromboembolic complications, compared with 20 patients on aspirin and 21 on placebo. 21 patients on warfarin were withdrawn because of non-fatal bleeding complications compared with 2 on aspirin and none on placebo.

Using Cox's regression model, previous myocardial infarction was a significant risk factor for development of thromboembolic complications. Age, gender, heart failure, chest pain, hypertensive heart disease, diabetes, systolic and diastolic blood pressure, smoking, relative heart volume, and left atrial size were all without statistical importance.

Interpretation:

Anticoagulation therapy with warfarin can be recommended to prevent thromboembolic complication in patients with chronic non-rheumatic AF.

References:

1. Lancet 1989;1(8631);175-9. Final results
2. Arch Int Med 1990;150:819-21. Risk factors for thromboembolic events

Clinical Topics: Anticoagulation Management, Heart Failure and Cardiomyopathies, Prevention, Acute Heart Failure, Smoking

Keywords: Myocardial Infarction, Platelet Aggregation Inhibitors, Warfarin, Blood Pressure, Risk Factors, Smoking, Thromboembolism, Chest Pain, Heart Failure, Cardiac Volume, Diabetes Mellitus, Hemorrhage


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