A new study must make clear what role a blood flow plays in the carotid artery in order to prevent a narrowing. Narrowing in the carotid arteries are one of the main causes of a stroke. But surgery can change the shape of a blood vessel so that the blood will flow differently. The blood flow plays an important role in the development of narrowing. There is a new study that compares two common operations for the treatment of narrowing of the carotid artery.
Every year in the Netherlands around 3,000 operations are done to remove a narrowing (stenosis) in the carotid artery. In the study set up by Prof. Michel Reijnen, specialized in vascular imaging and innovation at the University of Twente (Techmed Center) and Dr. Anne Saris, expert in Ultrasone Flow image formation at the Radboudumc, two common operations are compared. They received a turbo grant for this. PhD student Janna Ruisch works at Rijnstate, Radboudumc and University of Twente and conducts the research: “With the research we want to determine which operation is best for a patient.”
Plaque
When someone has a narrowing in the veins, plaque has accumulated on the inner wall of the vein. Ruisch explains that this happens often in places where the vascular wall experiences different resistance from the blood that flows through it. Usually that is where a vein splits. This becomes a problem when a piece of plaque comes loose and ends up at the brain through the blood.
“There it hides a blood vessel and then you get a stroke. It is important to detect the cause of the stroke, because even more plaque can release and you can get a stroke again. To prevent this, patients get surgery on the carotid artery where the plaque is removed,” explains Ruisch.
Two types of operations
At the moment there are two types of operations to remove a carotid artery. The first is carotis endarterectomy with patch angioplasty (CEAP). The surgeon removes the inner layer of the artery. A kind of plaster (patch) is applied of own tissue or synthetic material that makes the blood vessel wider. The second operation is the Eversie technology (ET). The blood vessel is opened in a different way and the surgeon removes the sick inside layer of the blood vessel from the inside. No patch is required for that operation.
Both operations have advantages and disadvantages. Ruisch says that after the examination the blood flow of the patient is measured six to eight after the operation. “We do that with a new ultrasound technique, with which we can absorb around 10,000 images per second. With the current systems we cannot absorb more than 100 images per second,” explains Ruically. Thanks to the new technology, they can accurately follow the relocation of groups of red blood cells in the blood vessel and thus portray the blood flow in detail. This research method is called Velocity Vector Imaging (VVI).
First results
In a large number of patients operated on with the patch technique, changes in blood flow show. The researchers say that the blood makes a rotating movement in the operated blood vessel. Is also called recirculation. The researchers expect the recirculation to be due to the operating technique. That is why they also want to investigate the blood flow of patients who are operated on with ET. They know from the literature that there is a greater risk of a new narrowing during the operating technique with patch. But according to the researchers, it has not yet been shown that this could be because the blood flow is different after the operation.
The researchers initially hope to detect the differences in bloodstream between CEAP and ET. They can then investigate whether these disturbed blood flows are the cause of the development of a new narrowing. For this study, patients will be investigated in the coming year from Rijnstate, Radboudumc, Elisabeth TweeSteden Hospital (ETZ) and Medisch Spectrum Twente (MST).
In this way it is considered which operating technology is the best for the patient in the longer term. Ruisch hopes to complete her PhD research in 2026. Optionally, the knowledge they gain with the examination can also serve as a basis for using this technique in other blood vessels in the body.
Last October, Charlotte Nawijn of the University of Twente (UT) obtained his PhD on a new technique that she has developed to improve blood flow through ‘smart pulse train’ of ultrasound.
