for oral anticoagulation if AF duration is clearly <48 hours (Singer et al 2004). Secondary prevention of stroke is also well established with warfarin (EAFT 1993) However in cases of an acute stroke, assessment of the risk from hemorrhagic transfor- mation in patients with large cerebral infarcts needs to be made. There is uncertainty about the optimal timing of administration of anticoagulants following acute stroke. Patients with AF can not only have thromboembolic stroke but also develop lacunar strokes secondary to hypertension and other comorbidities, and in such cases, warfarin is less effective (Evans et al 2001). There are little data available to assess the risks and beneﬁts of warfarin administration in the setting of acute stroke and AF. Once cerebral imaging has excluded hemorrhage, antithrombotic therapy could be commenced within two weeks after a small stroke or transient ischemic attack (TIA). In patients with AF who have had a large infarction or uncontrolled hypertension, antithrombotic therapy should be delayed until at least 2 weeks after the stroke. Practical aspects of anticoagulation The increasing use of oral anticoagulation therapy as thromboprophylaxis in AF has encouraged a move towards “point-of-care” (POC) and patient self-monitoring. POC for INR testing reduces INR waiting time (Murray et al 2004). Self-monitoring is shown to be safe and effective in a UK population (Fitzmaurice et al 2005). Patients undertaking anticoagulation self-monitoring should be trained by a com- petent healthcare professional and remain in contact with a named clinician. Despite clear guidelines, warfarin is underused, with a prescription rate of only 15%–44% among eligible patients (Bungard et al 2000; Fang et al 2004). Physician perceptions of risk beneﬁt are not always reliable and bleeding risks are often overestimated (Bungard et al 2000). Elderly patients are often suboptimally treated, despite the fact that this age group is most likely to beneﬁt from anticoagulation. A careful assessment of risk beneﬁt ratio, especially among the elderly, should be ascertained rather than simply relying on age or physician preference alone. Improved efforts at risk stratiﬁcation for thromboprophy- laxis would help target “high risk” subjects for anticoagula- tion. However, there is variation between the various risk stratiﬁcation criteria as well as inconsistencies between the published risk stratiﬁcation schema (Lip and Boos 2005). For example, the initial joint ACC/AHA/ESC guidelines in 2001 (Fuster et al 2001) recommended a risk stratiﬁcation Vascular Health and Risk Management 2007:3(1) Atrial ﬁbrillation schema where any “high risk” factor (previous stroke, TIA, embolism; hypertension; heart failure; age >75 years; mitral stenosis; prosthetic valve) or >1 “moderate risk” factor (age 65–75; diabetes; coronary artery disease) merits anticoagu- lation. Thus, a 45-year-old man with AF and hypertension would be recommended warfarin using the 2001 ACC/AHA/ ESC schema, but not by other published risk stratiﬁcation schemas. This schema has now been suitably modiﬁed (in 2006) to recommend anticoagulation for those with high risk of stroke such as those with prior thromboembolism and rheumatic mitral stenosis and for those patients with more than 1 moderate risk factor (age 75 years or greater, hyperten- sion, HF, impaired LV systolic function diabetes mellitus) (Fuster et al 2006). For patients with only one moderate risk factor the choice of warfarin versus aspirin must be carefully considered in the light of the perceived risk/beneﬁt for the individual patient. Another well-used and validated system, the CHADS2 risk stratiﬁcation scheme (Gage et al 2001) gives a numerical score to each of ﬁve risk factors (congestive heart failure, hypertension, age ≥75 years, diabetes and stroke/TIA, the latter receiving a score of 2). The total score (0–6) equates to a recognized future stroke risk (where a CHADS2 score of 0 would deﬁne a person as being at “low” risk (and suitable for aspirin) and ≥3 as a “high risk” (and warfarin is recom- mended). However, AF patients with previous stroke, TIA, or thromboembolism are considered to be at high risk of a further stroke or thromboembolic event. However using the CHADS2, such patients with this risk factor alone would only have a total CHADS2 score of 2, which would classify them as “moderate’ risk”. As a result of these uncertainties, the NICE guidelines has recommended an algorithm-based risk stratiﬁcation schema (Figure 1), which incorporates data from other previously pub- lished risk stratiﬁcation schemes and has been shown to be appli- cable to UK clinical practice. The NICE schema (which is based on the Birmingham risk stratiﬁcation schema) has been compared with the CHADS2 schema and was found to be comparable for predicting stroke and vascular events (Lip et al 2006). Conclusions The NICE guidelines for AF management are designed to assist in decision-making and are based on current best available evidence. In no way are they designed to replace clinical judgment and patient choices. Indeed, these guide- lines are an attempt to ease the burden on physicians and hospitals in managing this common yet enigmatic disease. The future of AF heralds interesting prospects with novel 113