Purpose and aims
The purpose of the trial is to study the prognostic impact of ECG investigation after
stroke or TIA.
The aim is to investigate if extended ECG screening after stroke as compared to standard
ECG screening reduces the occurrence of the primary composite endpoint of stroke, death
and intracranial bleeding in patients with stroke or transient ischemic attack (TIA).
Secondary aims include effects on major bleeding, myocardial infarction, pacemaker
implantation, atrial fibrillation prevalence, oral anticoagulation (OAC) treatment and
cost effectiveness.
Survey of the field Ischemic stroke is one of the leading causes of mortality worldwide,
and a major cause behind permanent disability in adults. Atrial fibrillation (AF) is the
most prevalent permanent clinically relevant arrhythmia with a steeply increasing
incidence with advancing age. Atrial fibrillation is also one of the strongest risk
factors for stroke. The increased stroke risk associated with AF can be markedly reduced
by OAC treatment.
Unfortunately, AF is paroxysmal and asymptomatic in a significant proportion of patients,
leading to lower detection rates and a similar proportion of stroke survivors with an
untreated risk factor and higher risk of stroke recurrence. For this reason, it is widely
recommended to make ECG recordings in patients suffering from stroke and TIA in order to
detect previously undiagnosed AF.
Despite this, no study so far has been reported to bring evidence on the benefit of ECG
AF screening in terms of reduced stroke recurrence and mortality after a stroke event.
However, several studies have reported the yield of new AF diagnosis in stroke/TIA
patients using different ECG recording strategies in different populations.
The knowledge gap on the possible benefits and cost effectiveness of ECG investigation
after stroke/TIA has led to a large variation in international recommendations, a
situation bringing uncertainty among policy makers, the profession and patients. The
variation in recommendations from different societies have unusual proportions. There is
also a large variation in clinical practice between different stroke units in Sweden.
Furthermore, since the magnitude of the net benefit (or net harm) of the ECG
investigation is not yet known, extensive clinical resources as well as patient effort
are today put into these ECG investigations without knowing about the benefit for the
patient or cost effectiveness.
Research Idea
The study will compare current standard ECG investigation after stroke/TIA with an
extended ECG investigation strategy and compare long-term prognosis in terms of hard
clinical endpoints among participants.
P: Patients aged at least 70 years treated in Swedish stroke units for ischemic
stroke/TIA who after 24-48 hours of standard ECG investigation have shown no signs of
atrial fibrillation
I: Extended ECG ambulatory recording, at least 2 separate recordings of 14 days each 2-4
months apart
C: standard Swedish ECG investigation, continuous ECG for 24-48 hours
O: Composite endpoint of recurrent stroke, all-cause mortality and intracerebral bleeding
For the year 2020, the mean age of Swedish stroke patients was 75 years, with a higher
mean age among women. Incidence of AF is strongly related to age as confirmed in
epidemiological studies and in screening studies. The selected cut-off age of 70 years
for this study will include three fourths of stroke patients targeting those at highest
risk for AF. However, higher age implies a risk for lower compliance to ECG recordings.
This has been taken into account when choosing ECG device. Hence, the chosen cut-off age
for inclusion is deemed to balance the yield of the ECG investigation, the benefit from
OAC treatment and stroke risk if AF is detected and the expected level of compliance to
procedures and treatment related to the study.
The ECG investigation in the control arm is based on the minimum recommendations for
stroke care issued by the Swedish board of health and welfare. There are however several
guidelines from international societies recommending higher ambitions for this
investigation, i.e longer ECG recordings. Several Swedish stroke units are implementing
ECG investigations after stroke/TIA with ambitions higher than those stated by national
minimum recommendations, assuming that these investigations will give more benefit to the
patient. The study design is calculated to give a marked difference between the control
and intervention groups to overcome the possible problem with an underpowered result
reported from a previous study in the field.
Plans and methods for pilot study The pilot study will engage five to six
patient-including stroke units which are already recruited. The pilot study is planned to
include 200-300 patients with the aim to evaluate feasibility of study management,
patient inclusion, inclusion rate, ECG recordings, flow of ECG data and short-term
follow-up of positive ECG findings.
Parallel to the pilot study, a comprehensive, digital survey on ECG investigation
practice covering all Swedish stroke units will be undertaken. This survey will be sent
to the stroke units commencing in september 2021. The outcome of the survey will give a
complete and up-to-date view of clinical practice and a possibility to identify suitable
sites for the main trial.
During 2020, there were 28 000 patients included in national stroke register for stroke
or TIA and three fourths of these patients were aged 70 years or older. The pilot and
main study are planned to include 3300 patients during 2021-2024.