GPs have been cautioned against continuing aspirin long-term in patients with stable coronary artery disease (CAD) who are also receiving anticoagulation therapy for stroke prevention.
Research presented at the American Heart Association annual conference in Chicago this week found there was a heightened risk of dementia in patients taking both an anticoagulant and antiplatelet.
This was particularly high among patients with poorly controlled warfarin dosing who were also receiving antiplatelet therapy with either aspirin or clopidogrel.
GP cardiology experts said the study highlighted concerns about patients being advised by their cardiologist to continue on aspirin or other antiplatet therapy long-term, which they stressed goes against current NICE and European guidelines that state there is no evidence of benefit and only evidence of harm with the combined treatments.
Over a 10-year period, patients taking both an antiplatelet and warfarin whose INRs were above 3 on a quarter or more of their monitoring tests – indicating overtreatment – were more than twice as likely to be diagnosed with dementia as were those whose INRs were above 3, less than a tenth of the time.
According to the researchers, this increase in dementia risk was greater than previously reported in a study of warfarin alone.
They suggest poor warfarin control, in combination with the antiplatelet, increases the risk of microbleeds in the brain that can result in dementia.
In the UK, clinicians are advised not to use the combination of an antiplatelet and warfarin.
The NICE atrial fibrillation guidelines, updated earlier this year, advise that aspirin should no longer be offered solely for stroke prevention.
The guidelines said it should only be continued if a patient is on it for another reason – such as stable coronary heart disease – and is at low risk of stroke, does not want to start on anticoagulation, or is advised to continue on aspirin as well as anticoagulation by a cardiologist, for example as part of dual or triple antithrombotic therapy following coronary stenting.
European Society of Cardiology guidelines on managing atrial fibrillation on managing atrial fibrillation indicate that the dual or triple antithrombotic therapy should not be continued long-term.
They state that for patients with stable CAD, with no acute ischaemic events or angioplasty or stenting procedure in the preceding year, antiplatelet therapy should be not be prescribed, as it does not add any further benefit over warfarin therapy and increases the risk of bleeding.
Dr Matthew Fay, a GPSI in cardiology in Shipley, West Yorkshire, and advisor to the Atrial Fibrillation Association, told Pulse the study highlighted the importance of good warfarin control, but also that there is no justification for continuing aspirin long-term for stable coronary disease in patients who need anticoagulation for stroke prevention.
Dr Fay said: ‘I think this is very interesting and strengthens the argument to have good warfarin control, and if this cannot be achieved to switch to a non-vitamin K oral anticoagulant. It also adds further weight to the European Society of Cardiology recommendation that we should stop the antiplatelet – not only do we have no evidence of any benefit, but we are gathering evidence that it is actually of harm.
‘We know an antiplatelet and an anticoagulant together increases the risk of bleeding – that’s why HAS-BLED score includes the use of aspirin or NSAIDs as a point – and now we’ve also got this research suggesting it may also lead to cognitive impairment.’
However, Dr Andrew Mimnagh, a GP in Sefton the urgent and unscheduled care lead at Sefton CCG, said cardiologists were in some cases advising continued aspirin use without a clear evidence-based reason.
Dr Mimnagh told Pulse: ‘Usually if there is a reason for the combined therapy – and the haemorrhagic rate on combined therapy is quite high – it is because it had been indicated by the cardiologist.
‘But to be honest, I have not seen any clear evidence of any rhyme or reason for it. I don’t see a pattern I can easily see and understand.’
Professor Ahmet Fuat, a GPSI in cardiology in Darlington and professor of primary care cardiology at Durham University, also told Pulse some patients with stable coronary disease were being kept on antiplatelet treatment needlessly – and said GPs should consider stopping it themselves or challenge the consulting cardiologist.
Professor Fuat said: ‘I think we have all experienced that, but there is really no good evidence for patients with atrial fibrillation and chronic stable coronary disease or stable angina to take both drugs because the risk of bleeding is greatly increased.
‘It’s a practice that shouldn’t be happening but still is and I don’t understand the rationale for it.’
He added: ‘I think GPs should challenge it, they should look at the individual patient and either stop it themselves, if they feel confident enough in doing it, or write back to the consultant asking why they want the patient to remain on both drugs which does greatly increase the risk of bleeding.’