Medical Matters: Taking the public pulse on stroke risk

Awake or asleep, our heart beats constantly. Driven by a natural pacemaker, it beats regularly at different speeds depending on the demands placed on it.

However, sometimes the beat becomes irregular, leading to a range of identifiable cardiac arrhythmias. One of the most common is atrial fibrillation (AF), which affects about 1-2 per cent of the population worldwide.

It is a major cause of stroke: the risk of stroke is five times higher in people who suffer from AF. About 2,000 people die from stroke in Ireland each year, while some 10,000 are admitted to hospital with stroke.

As we get older the prevalence of AF increases; it affects roughly 18 per cent of the population over 85. Consequently, as populations age, the rhythm disorder represents a significant cause of disability and death among older people.

As well as treatment aimed at correcting AF, doctors must focus on ways of preventing it flicking off clots that travel from the heart to the brain and cause stroke. Prescribing a drug to prevent clot formation is the key intervention.

For years the standard treatment for these patients was the drug warfarin.

But warfarin is notoriously fickle. It is one of the trickiest drugs when it comes to drug interactions, with the result that it can be easily rendered either ineffective or overly active in the body. And because of ongoing changes in how it is metabolised, warfarin’s anti-clotting action must be monitored with regular blood tests.

Less fickle drugs

This fickleness led to the development of an alternative group of drugs called novel oral anticoagulants (NOACs).

With the recent EU marketing authorisation of a drug called edoxaban (Lixiana), there are now four such agents available on the Irish market. (The others are apixaban, dabigatran and rivaroxaban.)

Providing a more predictable anticoagulant effect and one that doesn’t require frequent monitoring in the form of regular blood tests, the new-generation blood thinners also cause fewer drug interactions, and are less likely to cause brain haemorrhage as a side effect.

Major clinical trials have shown that NOACs are as effective or better at preventing strokes than warfarin.

A potential drawback to the use of NOACs – that there is no agent to reverse their blood-thinning action in an emergency – has been addressed for one of the new drugs, dabigatran, with an antidote for the others in the pipeline.

A research report published last month by Rand Europe looked at the challenges of anticoagulation management in AF. The Future of Anticoagulation Management in Atrial Fibrillation in Europe looked at the growing public health challenge of AF, and the need for improved awareness of the condition.

It found that policymaker awareness of AF is low, and that AF is viewed as a medical issue rather than a public health issue by politicians.

A key barrier to early diagnosis is a general lack of awareness of AF among the public. For example, a 2014 survey found that 87 per cent of people surveyed in France didn’t know what AF is.

One challenge identified in the report relates to the fact that most people who develop AF are asymptomatic. “This means that anticoagulation drugs that patients are put on . . . do not make them feel better and, as a result, patients may be less likely to comply with drug regimes,” it notes.

Among the report’s recommendations is a need for continued improvement in the personalisation of care.

“Improved patient stratification based on biomarkers, genomic information and heart imaging can lead to more individualised care that results in more effective management and treatment of AF,” the authors say.

How about teaching people to take their own pulse? A public health campaign encouraging pulse checks would seem to me to be a simple way to improve both awareness of and detection of AF.

mhouston@irishtimes.com muirishouston.com