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34 | Chapter 3 of ASCVD or a history of ASCVD. Controls were recruited through public advertisements, and were included between April 2014 and May 2015. Inclusion criteria for the controls were: no major illness, no statin or any other lipid-lowering medication use, and no history of ASCVD. A total of 221 FH patients were included in our study. Expecting 15%±7% difference in carotid plaque presence (primary endpoint) between FH patients and controls, at least 96 controls were required for a power of 80% and α of 5%. For C-IMT (secondary end point), we considered 0.05 mm to be a clinically significant difference and previously we observed standard deviation of +-0.12 mm, to obtain a power of 80%, α of 5%, at least 69 controls were required. All subjects were over 18 years old. Written informed consent was obtained from all participants and healthy volunteers. This study was in accordance with the declaration of Helsinki and was approved by the local ethical committee (MEC-2012-309);( MEC- 2013-556). Blood analyses Fasting blood was collected in EDTA, processed the same day, and plasma samples were stored at -80 o C. Lipid levels were measured using standard laboratory techniques. Carotid ultrasonography All carotid ultrasound scans and measurements were performed using a Panasonic CardioHealthStation (Yokohama, Japan) that uses a validated automated C-IMT capturing method (16). The scanning protocol is based on the ASE consensus (17), and has been previously published (18). In short, the plaque scans were performed bilaterally in the internal carotid artery, external carotid artery and common carotid artery. Plaques were defined as a local enlargement of the C-IMT of more than 50% of the surrounding C-IMT, or if the C-IMT was above 1.5 mm, and were scored as present or absent (19). C-IMT was measured over 1 cm length, at least 0.5 cm proximal of the bifurcation in the common carotid artery“, and measured in the end-diastolic phase which was identified by the vessel motion detector system based on the change in arterial diameter during the cardiac cycle (16). The C-IMT was measured twice on each side“, in a 45 degree angle determined by positioning the patients head against a 45 degree wedged pillow, and the mean of these four orientations was used in our study.