Letters to the Editor
- Doron Hickey, Benjamin Tsang, Dr Himabindu Samardhi, Dr Maria Santos, Dr Russell Denman, Dr Darren Walters, Dr Nick Bett
- Aust Prescr 2012;35:39-42
- 1 April 2012
- DOI: 10.18773/austprescr.2012.021
Editor, – We read with interest the article ‘Current management of atrial fibrillation’ ( Aust Prescr 2011;34:100-4 ). We commend the authors for their comprehensive overview of the topic and for presenting some pertinent issues relating to atrial fibrillation and stroke medicine.
From a stroke perspective, atrial fibrillation is not only a major risk factor for future stroke – it is an independent predictive factor for severe stroke and early death in patients with acute ischaemic infarction.1 Data from a large Japanese stroke registry demonstrated that acute ischaemic stroke severity was significantly higher in patients with atrial fibrillation compared to those without atrial fibrillation (median National Institutes of Health Stroke Scale score 12 vs 5, p
It is important to emphasise that transient ischaemic attacks contribute two points to CHADS2 scoring, and so even in the absence of any other CHADS2 risk factors, a transient ischaemic attack is a compelling reason to commence anticoagulation in a patient with atrial fibrillation.
It is significant to note that a history of falls is not a component of the HASBLED score. Clinicians commonly elect not to commence warfarin if the patient has a history of falls. The evidence supporting this clinical decision is lacking. In patients with atrial fibrillation and at risk of falls, the data suggest that stroke risk reduction with anticoagulation outweighs haemorrhage risk.2
The new oral inhibitors of thrombin and factor Xa have other limitations, including adherence and the lack of a test of anticoagulant activity.3 It remains to be seen how these drugs will affect thrombolysis decisions. An absolute contraindication to thrombolysis may have to apply to any patient thought to be taking dabigatran, due to the inability to quantify its anticoagulant effects and the unknown risk associated with thrombolysis in patients on dabigatran therapy.
Registrar/advanced trainee in neurology
Stroke Unit, Austin Hospital
Dr Himabindu Samardhi, Dr Maria Santos, Dr Russell Denman, Dr Darren Walters and Dr Nick Bett, authors of the article, comment:
We thank Doron Hickey and Benjamin Tsang for their comments and agree that there is no simple overall protocol for managing patients with atrial fibrillation and a history of falls. Their individual risks have to be assessed1 and weighed against the risk of stroke.
We are also concerned because of the lack of tests of anticoagulant activity and adherence5 for patients taking factor Xa and direct thrombin inhibitors, and because drugs to reverse their effects are not routinely available.6,7 There is insufficient information about the risks of administering thrombolysis, unfractionated heparin, enoxaparin or glycoprotein IIb/IIIa inhibitors such as abciximab to patients on these drugs.
Since our article appeared, trials of factor Xa inhibitors for atrial fibrillation have been published.8,9 Further studies will be required to compare the efficacy and safety of these drugs and direct thrombin inhibitors, especially in those with renal impairment.
Intern, Stroke Unit, Austin Hospital Heidelberg, Vic.
Registrar/advanced trainee in neurology, Stroke Unit, Austin Hospital Heidelberg, Vic.