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Related Subjects: |AF - General |AF and Anticoagulation |AF and Rate Control |AF and Rhythm Control and Cardioversion |AF ECG |DC cardioversion

Atrial fibrillation anticoagulation risk assessment

• CHA2DS2VaSc score: assess stroke risk in those with AF. CCF history (+1), hypertension (+1), age: 65-74 (+1), >75 (+2), diabetes mellitus (+1), stroke/ TIA or thromboembolism (+2), sex: female (+1), vascular disease or CAD, MI, PAD, or aortic plaque (+1). Adjusted annual stroke risk by score: (0) 0%, (1) 1.3%, (2) 2.2%, (3) 3.3%, (4) 4.0%, (5) 6.7%, (6) 9.8%, (7) 9.6%, (8) 6.7%, (9) 15.2%. Recommend anticoagulate if score >0 or 1. Discuss with patient.
• HAS -BLED score: assess bleeding risk. Hypertension (SBP >160 mmHg) (+1), abnormal renal (+1) and/or liver function (+1), stroke in past (+1), bleeding (+1), labile INR (+1), elderly age >65 (+1), drugs (+1) or alcohol abuse (+1). A score of 3 or more indicates increased 1 year bleed risk on anticoagulation sufficient to justify caution or more regular review. Risk is for intracranial bleed, bleed requiring hospitalisation or a haemoglobin drop >2 g/L or that needs transfusion.

CHADS2VASC Score

• For patients with non-valvular AF and a CHA2DS2-VASc score of 0, it is reasonable to omit antithrombotic therapy. For patients with non-valvular AF with prior stroke, transient ischaemic attack (TIA), or a CHA2DS2-VASc score of 2 or greater, oral anticoagulants are recommended.
• However one has to balance this with bleeding risk which can be quantified to some extent by the HAS-BLED criteria shown below. Interestingly the risks of bleeding often are similar to those of risks of ischaemic cardioembolic stroke e.g. stroke, blood pressure and age. It is a delicate balance but most of us would favour anticoagulation and managing any risks of bleeding as and when they happen. Expert and multidisciplinary decisions may be needed involving patients and those important to them in many instances.
• The risk of major haemorrhage attributable to anticoagulation therapy is typically between 0.5% and 1.0% per year. When the risks of ischaemic stroke exceed this then anticoagulation is recommended. The optimal intensity of anticoagulation appears to be an INR of 2.0 to 3.0. However, we are now seeing new drugs that are likely to replace warfarin. The holy grail of AF anticoagulation management is to find a drug more effective, but less harmful than warfarin that is cheap too.

HAS-BLED score for bleeding risk on oral anticoagulation in atrial fibrillation

• A HAS-BLED score of 3 or more indicates increased one year bleed risk on anticoagulation (of 3.7 Bleeds per 100 patient-years) sufficient to justify caution or more regular review.
• Increased risk of intracranial bleed, bleed requiring hospitalisation or a haemoglobin drop > 2g/L or that needs transfusion [Pisters R et al. 2010]
• Warfarin anticoagulation titrated to an INR of 2.0-3.0 is recommended for the average patient with a CHA2DS2-Vasc score =2 unless contraindicated (e.g., history of frequent falls, clinically significant bleeding, inability to obtain regular INR). Either Warfarin or Aspirin can be used for the average patient with a CHA2DS2-VASc score of 1 depending on physician discretion and patient preference. Aspirin 75-325 mg daily or no treatment may be reasonable depending on patient preference for the average patient with a CHA2DS2-VASc score of 0.

Anticoagulants