NICE suggest using the $CHA_2DS_2-VASc$ score to determine the most appropriate anticoagulation strategy.
| Risk factor | Points | |
|---|---|---|
| C | Congestive heart failure | 1 |
| H | Hypertension (or treated hypertension) | 1 |
| A2 | Age >= 75 years | 2 |
| Age 65-74 years | 1 | |
| D | Diabetes | 1 |
| S2 | Prior Stroke, TIA or thromboembolism | 2 |
| V | Vascular disease (including ischaemic heart disease and peripheral arterial disease) | 1 |
| S | Sex (female) | 1 |
The table below shows a suggested anticoagulation strategy based on the score:
| Score | Anticoagulation |
|---|---|
| 0 | No treatment |
| 1 | Males: Consider anticoagulation |
| Females: No treatment (this is because their score of 1 is only reached due to their gender) | |
| 2 or more | Offer anticoagulation |
Remember that if a $CHA_2DS_2-VASc$ score suggests no need for anticoagulation it is important to ensure a transthoracic echocardiogram has been done to exclude valvular heart disease, which in combination with AF is an absolute indication for anticoagulation.
See:
NICE warn us not to withhold anticoagulation solely on the grounds of age or risk falls. NICE now recommend we formalise this risk assessment using the ORBIT scoring system. Previously the HAS-BLED scoring system was recommended.
| Variable | Points |
|---|---|
| Haemoglobin <130 g/L for males and < 120 g/L for females, or haemtocrit < 40% for males and < 36% for females | 2 |
| Age > 74 years | 1 |
| Bleeding history (GI bleeding, intracranial bleeding or haemorrhagic stroke) | 2 |
| Renal impairment (GFR < 60 mL/min/1.73m2) | 1 |
| Treatment with antiplatelet agents | 1 |
There are no formal rules on how we act on the ORBIT score and individual patient factors should be taken into account. However, the following table acts as a guide:
| ORBIT score | Risk group | Bleeds per 100 patient-years |
|---|---|---|
| 0-2 | Low | 2.4 |
| 3 | Medium | 4.7 |
| 4-7 | High | 8.1 |