A significant proportion of strokes are thromboembolic in nature, arising from atherosclerotic plaque at the carotid bifurcation. It is now wellknown that inflammation plays a key role in atherogenesis and plaque destabilization. However the identification and characterization of the different inflammatory factors, as well as their relative importance, have not been clarified. This main aim of this study is to identify new risk markers for atherosclerosis and to characterize more precise methods for detection of the unstable carotid plaque with increased stroke-risk.

This project include patients with asymptomatic and symptomatic carotid stenosis >50%. Patients with acute ischemic stroke will also be included with carotid artery stenosis <50% (study 3). The patient group will undergo a clinical neurological examination, ultrasound of the neck-arteries and a blood sample. The majority will also have a CT-angiography of the neck arteries and a cerebral MRI or CT. Carotid plaques removed by surgery (carotid end-arterectomy) and thrombs removed by thrombectomy will undergo histological analyses.

Study 1:

Plasma markers will be analysed and compared to clinical symptoms, ultrasound assessment of the plaque, cerebral MRI (or CT).

Study 2:

Results from advanced ultrasound of the carotid plaque including assessment of plaque morphology will be compared to histology of the removed plaque. Plasma markers and clinic will be related to the findings. The correlation between the different diagnostic modalities and the histologic conclusion will be assessed.

Study 3:

This study focus on plasma markers in an acute ischemic stroke due to a carotid plaque compared to an acute ischemic stroke with a cardial embolic source. Thrombi removed from the cerebral artery by thrombectomy will undergo histological analysis and the results will be compared to plasma markers and stroke aetiology.

Inclusion Criteria:

• All patients with an atherosclerotic carotid stenosis >50% admitting one of the study centres as an in-patient or an out-patient will be considered for inclusion.
• Acute stroke patients treated with thrombectomy at Oslo University Hospital will be included even though the carotid stenosis is < 50%.

Exclusion Criteria:

• Malign disease
• Inflammatory disease

Patients with carotid atherosclerosis and/ or cerebrovascular symptoms/ disease.