Risk assessment and anticoagulation for primary stroke prevention in atrial fibrillation

Background and Purpose-Risk assessment before anticoagulation is important for effective stroke prevention in atrial fibrillation (AF). Methods-A study was undertaken in patients with AF to investigate the contribution of clinical and echocardiography (ECHO) criteria to treatment decisions on anticoagulation. Patients were stratified by age and stroke risk; contraindications to anticoagulation and warfarin use were assessed. The value of ECHO in treatment decisions, effect of age, and existing anticoagulation practice were evaluated. Results-The mean+/-SD age of 234 patients was 67.1+/-11.8 years, and 122 (52%) were women. Clinical risk factors were present in 74 of 80 patients (92%) aged >75 years compared with 99 of 154 patients (64%) less than or equal to 75 years (P<0.01), ECHO risk was identified in 94 of 154 patients (61%) less than or equal to 75 years, 16 (17%) of whom had no clinical risk factors. ECHO risk was present in 71 patients (88%) >75 years of age, and was associated with clinical risk factors in all patients. Eligibility for anticoagulation was seen in 72 of 154 (47%) to 105 of 154 (68%) patients aged less than or equal to 75 years, depending on the criteria used, and in 66 of 80 patients (83%) >75 years, regardless of criteria used (P<0.01). Warfarin was being used in 55 of 105 patients (51%) less than or equal to 75 years and 8 of 66 patients (12%) >75 years (P<0.001). Anticoagulation was being undertaken in 7 of 49 patients (14%) less than or equal to 75 years despite no clinical or ECHO risks. Conclusions-Accurate assessments of eligibility and appropriateness of anticoagulation in AF can be made on clinical criteria alone, especially in older people. The value of ECHO in treatment decisions is limited to patients less than or equal to 75 years of age with no clinical risk factors.