2.1 Study design and patients
This pilot study is a prospective observational single-blind study of
patients who underwent CEA at the Department of Cardiovascular Surgery
in the Magdalena - Clinic for Cardiovascular Diseases and at the
Department of Vascular Surgery in the University Hospital Merkur in
Croatia over a 3-year study period. Institutional ethic committee
approvals and Zagreb University School of Medicine ethic committee
approval were obtained, and all patients gave their written informed
consent. This study has been registered at the ISRCTN registry with
study ID ISRCTN46536832. The study was conducted as per the Helsinki
Declaration guidelines [24]. Identity of patients during data
collection was anonymised and protected using a unique patient number.
Clinical history taking and physical examination including a
neurological exam were performed by a surgeon. Clinical data including
history of cardiovascular disease, risk factors for atherosclerosis,
neurological event and timing since the most recent one, current medical
treatment and computed tomography (CT) scans of brain were recorded.
Stroke aetiology was determined based on a work-up including
neurological examination, duplex ultrasound, MRI, CT scan of brain and
echocardiography if required. Routine biochemical tests and highly
sensitive C-reactive protein (hsCRP) were performed preoperatively.
Before surgery, all patients underwent a duplex ultrasound plus MRI to
grade internal carotid artery (ICA) stenosis and assess the supra-aortic
and intracranial arterial system. The severity of carotid artery
stenosis was defined using the North American Symptomatic Carotid
Endarterectomy Trial Collaborators’ (NASCET) criteria [25].
Inclusion criteria were that the patient should be already scheduled for
CEA based on the indication for surgery with the consent to participate
in the study. CEA was indicated according to the ESVS guidelines and
recommendations of multicentric randomised controlled trials [1, 4,
25-27]. Exclusion criteria were contraindications to MRI (pacemaker,
metallic implant, claustrophobia), presence of suboptimal MRI
visualization of the carotid plaque or surgical specimen inadequate for
histological or immunohistochemical analysis.
Patients were divided into two groups based on the presence of symptoms
and the timing of the most recent symptom. Symptomatic patients were any
patients who suffered a carotid stenosis territory symptom within the
previous 6 months including ipsilateral stroke, transient ischaemic
attack (TIA) or amaurosis fugax. Patients without any history of recent
neurological symptoms or with nonspecific, non-hemispheric symptoms such
as dizziness or vertigo were considered as asymptomatic.