The risks and benefits of anticoagulation treatment
Cardiology Atrial fibrillation patients should be made aware of the risks and benefits of different types of anticoagulation treatments — and then have a say about which they would rather receive.
Recent figures show that an estimated 1.4 million people are at risk of strokes in the UK due to non-valvular atrial fibrillation (AF). Yet, ensuring they receive optimal treatment for AF isn't always straightforward, says Professor Anthony Rudd, National Clinical Director for Stroke, NHS England.
First, because anticoagulation treatment carries a bleeding risk, medical professionals have to decide which AF patients to give it to. Those with a CHADS-VASc score of two or over usually receive anticoagulation drugs as a matter of course. “However, the benefits of anticoagulation treatment for patients with a CHADS-VASc score of below two are outweighed by its risks,” says Rudd. “It's therefore not recommended for them. But as their score increases — and it inevitably will as they get older because of the associated risk of stroke — they should receive it.”
Management of warfarin
Rudd notes that current medical guidelines recommend treatment with either established anticoagulants or newer Direct Oral Anticoagulants (DOACS). Nothing else will do — and that includes aspirin. “Many AF patients still take aspirin, believing they are achieving something useful by doing so,” says Rudd. “But they aren't, as their specialist should be able to tell them.”
Optimising the dose for each AF patient can be difficult, particularly when prescribing warfarin, warns Rudd. “Warfarin is a difficult drug to manage,” he says. “The dose needed to produce effective anticoagulation will vary from patient to patient; plus, warfarin's efficacy may be disrupted by factors such as other medications, excess alcohol, or certain foods. It needs regular monitoring to check that the patient is not being under-treated — or over-treated, which is more likely to cause bleeds.”
Benefits of newer AF drugs
This is why many healthcare professionals now recommend the newer DOACs to treat the condition. “We know that the prescribed dose of these drugs will, by and large, have a consistent effect on everyone who takes it, which means AF patients don't need to be regularly monitored with anticoagulation blood tests,” says Rudd. Also, because the efficacy of warfarin can drop off due to disrupting factors, DOACs may overcome the problem of patients spending time outside of the Therapeutic Range — and therefore at risk of stroke.
DOACs do, however, have downsides. “Only one of them has a reversing agent, whereas there is an effective and quick way to reduce warfarin treatment if a patient starts to bleed,” says Rudd. “The new drugs are also a lot more expensive. But doctors and patients are now voting with their feet and the latest figures show that that over half of all prescribed anticoagulants are DOACs.” There are financial consequences to this, agrees Rudd; but, he argues, if these drugs are more effective at preventing strokes then their cost could be justified. “Over a five-year period, the health care cost for someone with an AF-induced stroke could be as much as £100,000,” he says.
Sharing decision making
It's important for healthcare professionals to fully inform patients about these possible treatment choices, and then share decision-making with them. “Patients must understand the risk and benefits of both sorts of treatments — or of not receiving any treatment,” says Rudd. “Unless there are special circumstances, I'm fairly forceful that anticoagulation is the best course, because the consequences of not being treated can be so great.”
More has to be done to understand unwarranted variation in AF-related strokes, admits Rudd. “There are some centres that have done excellent work to improve detection rates and treatment rates: Bradford, for example, and Lambeth and Southwark in London. It's interesting that patients from the least deprived areas of Britain are more likely to have a prior history of AF — although it's not clear why.”
EDX/18/0302 June 2018