Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT02405845 |
| Other study ID # |
OHSN-REB 20150092-01H |
| Secondary ID |
|
| Status |
Completed |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
March 2015 |
| Est. completion date |
September 2021 |
Study information
| Verified date |
October 2021 |
| Source |
Ottawa Hospital Research Institute |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
Hardened plaque located in the carotid arteries can cause stroke or transient ischemic attack
(TIA). This type of plaque is linked to unstable free-floating thrombi (FFT). FFT are blood
clots that form in a blood vessel, and are at the highest risk for travelling within the
bloodstream and causing strokes. Physicians are able to see this type of plaque with computed
tomographic angiography (CTA) but FFT look very similar to stable types of plaque that do not
require urgent treatment.
Distinguishing between these plaques is important because it affects the choice and urgency
of treatment that patients receive.
The researchers have found a promising visual marker on CTA scans. The goal of this study is
to determine if this visual marker seen on CTA scans will help to distinguish FFT plaque from
stable plaque.
Description:
Atherosclerotic plaques at the origin of the internal carotid artery (ICA) can cause
TIA/stroke, and are well-visualized with CT angiography (CTA). Those plaques associated with
unstable free-floating thrombi (FFT) are at highest risk for embolization and stroke.
Unfortunately, FFT have a similar appearance to stable ulcerated plaques on CTA: both appear
as intraluminal filling defects of varying length and morphology. Distinguishing these
entities is critical as it affects the choice and urgency of treatment (antithrombotics vs
revascularization). Using a retrospective study, we have previously proposed a promising CTA
imaging marker to distinguish FFT from stable ulcerated plaque. It is hoped that after the
data is collected from this prospective study to one day initiate a multi-centre study.
In our prior research, we proposed a reasonable "gold standard" for FFT diagnosis. We
followed patients presenting with circular filling defects on CTA (doughnut signs) suspicious
for either FFT or ulcerated plaque with serial CTAs after medical therapy. Those that
diminished or resolved with antithrombotic treatment (or those that unfortunately "resolved"
by embolizing distally) were presumed to be "true FFT" in contrast to those that remained
unchanged. We then assessed the performance of a variety of imaging parameters to
differentiate FFT from ulcerated plaque: we tested linear measurements, morphology, degree of
stenosis, as well as relevant clinical factors. These parameters were measured by
neuroradiologists as well as an innovative semi-automated shape analysis. Using a
retrospectively established cohort, we were able to derive 3.8 mm as an optimal
cranial-caudal length threshold of the filling defect that can potentially help distinguish
FFT from plaque, with 88% sensitivity and 86% specificity.
We will prospectively identify consecutive patients presenting with TIA/stroke within 72 hrs
of symptom onset with an ICA intraluminal filling defect on CTA. We will review the imaging
data and measure the cranial-caudal length of the filling defect. Patients will receive a
follow-up CTA in one week as per the current clinical standard of care, and if the defect is
still unresolved, a third CTA will be repeated after a second week if unresolved, and a
fourth at one month (research). We will measure cranial-caudal length of the filling defect
at each time interval, blind to the previous measurements. Resolution of the filling defect
at any point is diagnostic of FFT, whereas its static appearance after 1 month is diagnostic
of ulcerated plaque. For this pilot study, measure rate of enrolment, adherence to study
protocols, attrition rates, and proportion of patients with FFT. For the exploratory
objective, we will record treatment choice, dose, and duration.
