Is it possible to estimate cerebro–vascular risk on the basis of the composition of carotid atherosclerotic plaques?

Abstract

Different models for the prediction of cardiovascular and cerebro-vascular events are used, based on the presence of risk factors. This is a statistical risk-assessment model. Recently, research has been focused on identifying indicators that would enable us to directly assess the risk in certain individuals. These indicators include the detection of the presence and composition of atherosclerotic plaques. Atherosclerotic plaques found in a majority of adults represent a potential cause of vascular complications. Recently, not only thestage of atherosclerotic plaques or the degree of arterial stenosis but also the knowledge of atherosclerotic plaque composition is gaining in importance. Particularly unstable plaques, which are prone to disintegration and the associatedthromboembolic complications, are considered dangerous. Therefore, recently intensive research has been underway to find methods that would enable us to identify the composition and in particular the biological activity of atherosclerotic plaques. Namely, the latter two features determine the stability of plaques or their proneness to rupture and disintegration. While classical angiography is invasive and associated with irradiation, it only provides information on the degree of vascular lumen stenosis but not also on vascular wall composition. Ultrasonography is a basic non-invasive imaging method, which also provides an insight into the composition of vascular wall, however, since mainly superficially situated arteries are accessible by US, its investigation potential in distinguishing between different tissue structures is rather limited. Recent computer programs for analysis of ultrasound images and quantifying various components of atherosclerotic plaques provide a more accurate determination of the composition of atherosclerotic plaques, but do not yield information on the biological activity of atherosclerotic lesions.A newer generation of imaging methods facilitates more accurate morphological and spatial analysis of atherosclerotic plaques (computertomography – CT) and higher contrast and differentiation of soft tissues (magnetic resonance angiography – MRA), while nuclear investigationtechniques (positron emission tomography – PET) in combination with computer tomography provide information on the metabolic and inflammatory activity of atherosclerotic plaques. The latter, however, is associated with the stability of atherosclerotic plaques. So far, a combination of anatomical and biological imaging methods seems to be the most promising option for identifying atherosclerotic lesions and their characteristics: PET plus CT and PET plus MRA. It is expected that in the near future the described investigation methods will enable us not only to detect but also to recognize the most dangerous atherosclerotic plaques and thus also identify the individuals at risk, who require the most effective preventive measures and consistent treatment of the present risk factors for atherosclerosis.