Atherosclerosis is caused by accumulation of fat, primarily cholesterol in the wall of the arteries. When the fat builds up in the arterial wall it causes thickening of the vessel wall and the thickened area bulges out into the vessel. These thickened areas are called atherosclerotic plaques.
Strokes resulting from blood clots that migrate to the brain from plaque in the carotids cause 2.5% of all deaths. Today, plaques that cause more than 70 % constriction of the carotid in stroke patients are removed surgically to avoid future strokes. The hypothesis is that the blood clots are formed when the plaque surface rupture. The composition of the plaque is affecting the rupture risk. Plaque with a large amount of fat and blood are more prone to rupture. However, studies show that only half of the removed plaques have ruptured. Also, removing the plaque is far from a complete safe guard against future stroke. We believe that the blood flow around the plaque also is an important factor for rupture risk. Additionally, if there is stagnant flow, blood clots could form despite an intact plaque surface. Unfortunately, current clinical tools are insensitive to these effects. Consequently, there is a clear and urgent need to improve carotid plaque assessment in order to more accurately assess risk of progression and rupture in patients as well as to improve risk management in patients with carotid plaques.
Improved carotid plaque risk assessment
In this project we aim to improve carotid plaque risk assessment both for better assessment of overall cardiovascular risk and for better decision support in which patients will benefit from surgery.
The project develops tools for automated visualization and quantification of carotid plaque composition and hemodynamic effects on the vessel wall. This will be achieved by combining advanced quantitative magnetic resonance imaging methods with novel image analysis. In this way, we will automatically identify plaque severity based on the extent of fat and blood within the plaque. Similarly, we will provide assessment of the impact of turbulent flow on the vessel wall. The methods will be evaluated in patients with carotid atherosclerotic plaques to optimize and establish the reliability of the technical developments in a clinical setting.
Successful implementation of the project will enable new approaches for risk stratifying carotid plaques clinically and improved cardiovascular risk management. This will not only improve the selection of patients for preventive care and surgery, but also, through improved management, reduce healthcare costs.
Photo credit John Sandlund www.johnsandlund.se