Five-fold increased risk of ischaemic stroke
“Patients with AF have a five-fold increased risk for ischaemic stroke, and most need oral anticoagulation,” explained principal investigator Ron Pisters (University Hospital, Maastricht, Netherlands). “With over 4,000 AF related strokes occurring in the Netherlands each year, we decided to investigate whether better therapies are needed or whether existing guidelines should be better implemented.”
CHADS2 score to simplify risk stratification
The 2001 ACC/AHA/ESC AF guidelines recommend anticoagulation for patients considered at medium or high risk of thromboembolism. In 2005 the Euro Heart Survey AF found that only 67% of eligible patients were receiving anticoagulation. Therefore, the 2006 ACC/AHA/ESC AF updated guidelines incorporated the CHADS2 score (Congestive heart failure, Hypertension, Age (75 years and older), Diabetes mellitus and history of Stroke/TIA (2 points), to simplify risk stratification. Guidelines say that anyone with a score of one or higher should be given oral anticoagulation.
Adherence to guidelines would have led to greater prevention
Pisters and colleagues retrospectively examined 1,120 patients admitted between 2003 and 2006 to University Hospital, Maastricht, with a diagnosis of ischaemic stroke. Results showed that 163 (15%) of the patients had a diagnosis of AF, with 89 patients having a diagnosis prior to hospital admission and 77 receiving a diagnosis during their hospital stay. At admission only 44 out of the 89 patients with known AF (49%) received guideline adherent antithrombotic therapy, and at discharge 15% of patients with known AF were undertreated according to guidelines.
Adherence to guidelines, the authors estimate, would have led to prevention of 25 out of the 89 cases of stroke but, on the down side, to five more cases of intracranial haemorrhage. However, the results showed that, overall, five times more strokes could be prevented than cases of intracranial haemorrhage caused.
“The main reasons physicians don’t prescribe oral anticoagulation is the unreal fear of bleeding caused by the vitamin-K antagonists and the workload of monitoring anticoagulation levels,” said Pisters. “To improve the situation, physicians need to calculate the CHADS2 score during every AF patient contact, and then act on the findings.”
This article refers to the Antithrombotic guideline adherence in atrial fibrillation patients admitted with stroke. Do we use our safety-belt? presentation by R Pisters (Maastricht, NL) that was held as part of the Pharmacological treatment in atrial fibrillation Abstract Session chaired by P Rakovec (Ljubljana, SI), A Dorszewski (Bad Oeynhausen, DE). Sessions details here.