Morphological and Serological Criteria of Plaque Vulnerability: Risk Assessment for Symptomatic and Asymptomatic Carotid Artery Stenosis

The aim of this study is to investigate the association of sonographic and histological features of the plaque among each other and with biomarkers of cardiovascular risk. The predictive value of these factors concerning the long-term clinical outcome after carotid endarterectomy will also be assessed. This may help to improve the identification of patients with carotid artery stenosis who will benefit most from carotid endarterectomy. The investigators major hypothesis is that the morphology of carotid plaques is associated with objectifiable sonographic parameters, in particular with the greyscale median. Second, the investigators hypothesize that sonographic and histological plaque morphology are associated with certain biomarkers of cardiovascular risk. Identification of 'vulnerable plaques' on the basis of a peripheral blood draw and a sonographic investigation may enable the treating physician to focus resources on patients who will benefit most form therapeutic interventions for primary prevention of ischemic stroke.

The indication for revascularization of carotid artery stenoses is typically based on the degree of stenosis and the presence of symptoms. Recent evidence suggests that the risk of embolization from an atherosclerotic plaque may be associated with plaque density as assessed sonographically by determination of the greyscale median. Also, an association of serum proteins vascular endothelial growth factor (VEGF), hypoxia inducible factor (HIF) and pigment epithelium-derived factor (PEDF), matrix metalloproteinases 2, 8 and 9 with unstable plaques has been reported.

The VUCAP study will include patients undergoing carotid endarterectomy for symptomatic or asymptomatic carotid artery disease. Sonographic and serological markers of plaque vulnerability will be compared with histological features of the plaque and clinical presentation (symptomatic vs. asymptomatic). Preoperatively, the greyscale median of the plaque is assessed. Histomorphological investigation of the carotid plaques will be performed. Serological investigations will include markers of inflammation, thrombo-modulatory factors, lipid fractions and other parameters that have been associated with unstable plaques.

The aim of the present study is to assess the ability of pigment epithelium-derived factor (PEDF), vascular endothelial growth factor (VEGF), hypoxia-induced factor 1 alpha (HIF 1-α), matrix metalloproteinases 2, 8 and 9 to differentiate between vulnerable and stable carotid artery plaques. Identification of 'vulnerable plaques' on the basis of a peripheral blood draw and a sonographic investigation may enable the treating physician to focus resources on patients who will benefit most form therapeutic interventions for primary prevention of ischemic stroke.

Eligibility Criteria:
Inclusion Criteria:

* asymptomatic stenosis of internal carotid artery \>70%
* symptomatic stenosis of internal carotid artery \>60%
* planed surgical treatment of the stenosis

Exclusion Criteria:

* pregnancy
* symptomatic coronary heart disease
* myocardial infarction or acute coronary syndrome in the past 3 months
* acute peripheral artery occlusion in the past 3 months
* immaturity
* existence of a guardianship