Clinical Trial Details
— Status: Completed
Administrative data
NCT number |
NCT02982850 |
Other study ID # |
2016-0869 |
Secondary ID |
|
Status |
Completed |
Phase |
Phase 4
|
First received |
|
Last updated |
|
Start date |
December 2016 |
Est. completion date |
October 2020 |
Study information
Verified date |
January 2021 |
Source |
Asan Medical Center |
Contact |
n/a |
Is FDA regulated |
No |
Health authority |
|
Study type |
Interventional
|
Clinical Trial Summary
The prevalence of AF, which is tachyarrhythmia, is approximately 2% of the entire population
and 5% of the population at the age of 60 or older. AF is the cause of approximately 20% of
all events of ischemic stroke, and patients with AF are known to be at 6 to 10% risk of
ischemic stroke per year. Patients with valvular AF are known to have a higher incidence of
stroke than patients with nonvalvular AF. However, the relevant data are insufficient as
large randomized studies comparing NOAC treatment with warfarin, a conventional treatment,
did not include many patients with moderate and severe valvular AF.
Ischemic stroke is divided into symptomatic stroke with brain lesions on brain magnetic
resonance imaging (MRI) and silent cerebral infarct with lesions on brain MRI but without
stroke symptoms. According to a brain MRI follow-up study, the incidence of silent cerebral
infarct was 17.7% (254 subjects) over a period of 5 years, with 11.4% of 254 subjects
reporting to have experienced symptoms. This means that the incidence of silent cerebral
infarct is approximately 9 times that of symptomatic stroke. In addition, patients with a
history of silent cerebral infarct are known to be approximately twice more likely to
experience stroke in the future than those without a history of silent. Brain microbleed is
easily detected by brain MRI and is a well-known independent predictor of intraparenchymal
hemorrhage and silent cerebral infarct. The prevention of stroke by the study drug can be
indirectly assessed based on the incidence of silent cerebral infarct and brain microbleed on
brain MRI. Investigators tried to compare effect of dabigatran with conventional treatment in
terms of prevention of stroke by comparing incidences of silent cerebral infarct and brain
microbleed and symptomatic stroke using brain MRI.
Description:
Amongst different types of cardiac arrhythmia, tachyarrhythmia shows the highest prevalence.
The prevalence of AF, which is tachyarrhythmia, is approximately 2% of the entire population
and 5% of the population at the age of 60 or older. AF is the cause of approximately 20% of
all events of ischemic stroke, and patients with AF are known to be at 6 to 10% risk of
ischemic stroke per year. In addition, AF results in heart failure and doubles mortalities.
With an increase in the elderly population, there is a worldwide trend of increased
hospitalization rate and medical cost caused by cardiac arrhythmia. In addition, whereas AF
has been known to occur mainly in the elderly, the incidence of AF is also increasing in
younger population, which is thought to be associated with the increased prevalence of heart
diseases, dietary changes, and increased environmental pollution.
A. Previous studies related to atrial fibrillation and stroke i. While AF is characterized by
a single electrophysiological abnormality, depending on cases, the risk of stroke varies from
below 1%/year to 20%/year or above.
ii. New oral anticoagulant (NOAC), left atrial appendage occlusion, etc. have been studied as
treatments to replace warfarin and aspirin and their effects have been also demonstrated.
B. Relevant study trends and limitations i. Patients with valvular AF are known to have a
higher incidence of stroke than patients with nonvalvular AF. However, the relevant data are
insufficient as large randomized studies comparing NOAC treatment with warfarin, a
conventional treatment, did not include many patients with moderate and severe valvular AF.
ii. The exclusion of valvular AF from the study is based on the assumption that the
pathogenesis of thromboembolism would vary according to the type of AF. However, the
difference in pathogenesis of thromboembolism between valvular AF and nonvalvular AF remains
unknown.
C. Study features i. Ischemic stroke is divided into symptomatic stroke with brain lesions on
brain magnetic resonance imaging (MRI) and silent cerebral infarct with lesions on brain MRI
but without stroke symptoms.
ii. According to a brain MRI follow-up study, the incidence of silent cerebral infarct was
17.7% (254 subjects) over a period of 5 years, with 11.4% of 254 subjects reporting to have
experienced symptoms. This means that the incidence of silent cerebral infarct is
approximately 9 times that of symptomatic stroke.
iii. In addition, patients with a history of silent cerebral infarct are known to be
approximately twice more likely to experience stroke in the future than those without a
history of silent.
iv. Brain microbleed is easily detected by brain MRI and is a well-known independent
predictor of intraparenchymal hemorrhage and silent cerebral infarct.
v. The prevention of stroke by the study drug can be indirectly assessed based on the
incidence of silent cerebral infarct and brain microbleed on brain MRI at the start of study
and at 1 year follow-up.
D. Significance of the study i. The incidence of stroke is higher in valvular AF than in
nonvalvular AF. ii. There is lack of data on dabigatran treatment, an NOAC, in valvular AF.
iii. To compare dabigatran with conventional treatment in terms of prevention of stroke by
comparing incidences of silent cerebral infarct and brain microbleed and symptomatic stroke
at the start of study and at 1 year follow-up using brain MRI.
This is a single center, prospective, randomized study to evaluate the effectiveness and
safety of dabigatran versus conventional treatment in patients with valvular AF by comparing
the incidence of silent cerebral infarct and brain microbleed using brain MRI. Aspirin or
warfarin treatment will be continued in patients randomly allocated to conventional treatment
group, and changed to dabigatran treatment in those randomly allocated to dabigatran group.