Clinical Trial Details
— Status: Recruiting
Administrative data
| NCT number |
NCT06290271 |
| Other study ID # |
CISTAR |
| Secondary ID |
|
| Status |
Recruiting |
| Phase |
|
| First received |
|
| Last updated |
|
| Start date |
August 1, 2023 |
| Est. completion date |
December 2024 |
Study information
| Verified date |
February 2024 |
| Source |
Chonbuk National University Hospital |
| Contact |
Chan-Hyuk Lee, Prof. |
| Phone |
+82-052-250-7089 |
| Email |
bluewave0210[@]gmail.com |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Observational
|
Clinical Trial Summary
There has been consistent research on the cerebral blood flow features in ischemic stroke
patients with acute occlusion of major intracranial arteries. However, studies analyzing the
overall features of the major intracranial artery blood flow in the periods of pre and
post-recanalization are still lacking. Time-of-flight magnetic resonance angiography
(TOF-MRA) is extensively utilized to evaluate the intracranial arteries. The arterial signal
intensity from MRA-TOF varies across subjects and arterial subtypes, leading to the
development of the Signal Intensity Gradient (SIG) concept. SIG has demonstrated a strong
correlation with Computational Fluid Dynamics (CFD), a known method for reflecting wall shear
stress. SIG could be associated with the pathophysiology of wall shear stress. We aim to
investigate the blood flow patterns and characteristics in the periods of pre and
post-recanalization using SIG.
Description:
1. Background The prognosis for ischemic stroke patients experiencing acute major
intracranial artery occlusion is determined by a variety of factors. The status of
arterial recanalization and the time taken to achieve recanalization play pivotal roles
in determining patient outcomes. Even under similar conditions, short or long-term
outcomes significantly differ among patients, making it challenging to solely explain
with traditional risk factors. An acute occlusion in a major intracranial artery results
in significant alterations in cerebral blood flow, enhancing flow through the Circle of
Willis and collateral circulation to make up for the reduced blood supply to the
affected area. After thrombectomy, the patterns of intracranial blood flow. changes
again.
Wall Shear Stress (WSS) is the frictional resistance force exerted by blood flow as it
directly interacts with the vascular walls, and it serves as a critical indicator of
vascular health. WSS is well-known for its correlation with atherosclerotic changes.
Studies have shown that WSS in the internal carotid artery of ischemic stroke patients
is lower compared to healthy individuals. Additionally, WSS was found to be reduced in
the carotid artery of patients with lacunar infarctions. WSS in large artery strokes was
lower than in the cardioembolic group. There have also been reports linking WSS to the
progression of Moyamoya disease, suggesting that WSS may be associated with various
vascular pathophysiologies, not just atherosclerotic changes.
Time-of-Flight Magnetic Resonance Angiography (TOF-MRA) is a commonly used brain MRI
technique, often utilized in conjunction with CT angiography to assess the course and
condition of intracranial arteries. The signal intensity from MRA-TOF presents diverse
distributions across different subjects and arteries. Based on this, the concept of
Signal Intensity Gradient (SIG) has been derived. SIG has shown a strong correlation
(correlation coefficient >0.8) with Computational Fluid Dynamics (CFD), a well-known
method for assessing blood shear stress. In patients with the large artery
atherosclerosis subtype of stroke, the SIG in the ipsilateral internal carotid artery
was significantly lower than that on the contralateral side. These findings suggest a
potential association between SIG, vascular shear stress, and the related
pathophysiology.
There is no need for additional imaging beyond TOF, and it is possible to measure even
arteries of relatively small diameter. Therefore, SIG enables the analysis of shear
stress pattern in major cerebral arteries before and after recanalization.
2. Aims We aim to investigate the blood flow patterns and characteristics in the periods of
pre and post-recanalization using SIG.
3. Target number of participants A total of 160 participants (20 individuals from each
center, total 8 centers)
4. Sample size assessment Although there haven't been many similar studies in the past, a
study (PLoS One. 2020 Sep 21;15(9):e0238620) conducted a hemodynamic evaluation before
and after major vessel recanalization, analyzing 11 patients. Sample size estimation
using G*Power indicated that registration of approximately 144 patients would be
necessary. Taking into account factors such as image quality, we anticipate an
additional recruitment of about 10%, resulting in a final target of 160 cases.
5. Data Acquisition This study is a retrospective cohort study that involves the collection
of electronic medical records and imaging data.
Imaging Data to be Collected: (All images will be collected as DICOM files)
- Brain MRI (Specific imaging conditions: Fluid Attenuated Inversion Recovery,
Susceptibility Weighted Imaging, T1-Weighted Imaging, T2-Weighted Imaging,
Diffusion Weighted Imaging, Apparent Diffusion Coefficient)
- Brain MRA (Specific imaging conditions: source images from both extra and
intracranial TOF-MRA, and 3D TOF-MRA)
6. Derivation of Intravascular Shear Stress (SIG) Through Image Analysis The transferred
DICOM files are reconstructed into 3D vasculature using a separate software (VINT).
SIG values for the major arterial segments within the cranial cavity are extracted.
The major arterial segments are as follows, and the points where laminar flow of blood
is formed were selected, considering the characteristics of the SIG technique:
- Internal Carotid Artery: C1 distal segment prior to the horizontal intrapetrous
segment
- Vertebral Artery: V4 distal segment just before the formation of the basilar artery
- Basilar Artery: mid to distal segment
- Middle and Anterior Cerebral Arteries: proximal 1/2 or 1/3 segment
- Posterior Cerebral Artery: P2 segment distal to the posterior communicating artery
The measurements can be calculated into various SIG values (average, maximum,
minimum, deviation).
7. Statistical Analysis Each patient will be classified into two groups based on their
blood flow characteristics before and after recanalization. In a preliminary study, two
types of blood flow (shear stress) changes were observed. Firstly, there was a pattern
in which, following cerebral vascular occlusion, blood flow to the ischemic area was
provided, and upon recanalization, it returned to the typical blood flow pattern.
Secondly, there was a case where the overall blood flow in the major cerebral vessels
increased after recanalization. To analyze these patterns, Paired t-test and Wilcoxon
Signed-Rank Test will be used. (While this study is expected to proceed in the same
manner as the group classification in the preliminary study, the classification method
may be revised as the research progresses.)
For comparing mean values between groups, Independent Samples t-Test and Mann-Whitney U Test
will be utilized. Categorical variables will be analyzed using the Chi-square Test or
Fisher's Exact Test. Variables such as mRS (modified Rankin Scale), which are ordinal, will
be assessed using the Mann-Whitney U Test or Wilcoxon Rank-Sum Test to utilize the median
values.
