Stroke patients have a high risk of developing atrial fibrillation (AF), which increases their risk of a further stroke. A team led by researchers at the University of East Anglia (UEA) has developed a new tool to predict this risk, and reported that it performs better than current scoring systems, and thus could help to reduce the risk of secondary stroke.
The team studied data from 323 patients referred to a single hospital in Cambridge for monitoring with an implantable loop recorder (ILR) — a subcutaneously-implanted single-lead electrocardiographic (ECG) monitoring device — after an embolic stroke of undetermined source (ESUS, 293 patients), or a transient ischaemic attack (TIA, 30 patients).
Almost Half of Stroke Patients Developed AF
The researchers recorded clinical variables at baseline, and analysed transthoracic echocardiograms while patients were in sinus rhythm. AF was detected in 152 (47.1%) patients over a mean follow-up of 710 days, with over half detected in the first 6 months.
The study, published in the European Journal of Preventive Cardiology, and simultaneously presented at the European Society of Cardiology (ESC) Congress in Amsterdam, revealed four specific factors predictive of which patients went on to develop AF:
- Increasing lateral PA (the time interval from the beginning of p wave on surface electrocardiogram to the beginning of A' wave on pulsed wave tissue Doppler of the lateral mitral annulus) (OR 1.011)
- Increasing Age (OR 1.035)
- Higher Diastolic blood pressure (DBP) (OR 1.027)
- Abnormal LA reservoir Strain (OR 0.973)
The PADS score was internally validated and showed consistent results. The researchers said that as transthoracic echocardiography was recommended for all ESUS patients, PADS was "a relatively easy score to calculate", to identify the risk of AF so that ILR could be targeted to individuals most at risk.
Novel PADS Score a "Dedicated Risk-Stratification Tool"
They concluded that the novel PADS score "should be considered a dedicated risk-stratification tool for decision-making regarding the screening strategy for AF in stroke". In addition, it might offer "the ability to target anticoagulation in a suitable group of stroke patients at high risk of future AF who are currently in sinus rhythm".
While AF per se is not life threatening, it increases the risk of stroke or TIA up to five-fold. Anticoagulation reduces stroke recurrence by almost 65%. Lead researcher Vassilios Vassiliou, clinical professor of cardiac medicine at the UEA's Norwich Medical School, explained that identifying which patients were at high risk of AF to identify those who could benefit from prolonged rhythm monitoring and earlier anticoagulation was therefore "very important".
The four PADS parameters "were consistently present" in patients who developed AF, he said, and the model predicted those who developed AF over the following three years, and were therefore at increased risk of another stroke.
"This is a very easy tool that any doctor can use in clinical practice," Prof Vassiliou said, and could "potentially help doctors provide more targeted and effective treatment".
Increased AF Prevalence but Lowered Mortality
According to research funded by the British Heart Foundation, the prevalence of AF has increased by 72% in England over the last two decades, and earlier this year surpassed passed 1.5 million for the first time, now affecting one in 45 people.
Fortuitously, last week researchers from the University of Leeds reported at the ESC that AF patients were now 50% less likely to die from a heart attack or stroke than they were at the start of the millennium. Analysis of the health records of 72,412 patients revealed that over the 16-year study period, the one-year post-diagnosis mortality from AF-related cardiovascular and cerebrovascular diseases had more than halved, which they attributed to better detection and treatment.
Senior author Chris Gale, professor of cardiovascular medicine at the University of Leeds, said: "Advances in health care have now reduced the chance of having a stroke related to AF, and of dying as result of it, if AF is detected and treated."
Asked by Medscape News UK to comment on the new prediction tool, Dr Clare Jonas, research communications lead at the Stroke Association, said that not only did AF increase stroke risk five-fold, but also these strokes were often more deadly and disabling.
"We know from stroke survivors that having another stroke is often one of their biggest fears. Therefore, we welcome the possibility of a new predictive tool that makes it easier to identify which stroke survivors are likely to have AF. Tools like this, which use widely available health measures, could make targeted monitoring of heart health much easier, so that more strokes can be prevented."
However, the research was "still a way from the clinic", and the decision to prescribe anticoagulants to reduce stroke recurrence risk in AF "will always need to be made on an individual basis", she said.
"Identifying and treating AF before someone has a stroke is also important," she added. The Stroke Association is funding a study to develop an AF risk score for targeted screening to prevent strokes happening in the first place.