INTRODUCTION
Atherosclerosis is considered a systemic disease. In patients with Atherosclerotic disease effects on various sections of the arterial system, functional and structural changes in several segments of the arterial system are expected1. Dysfunction of the endothelium leads to thickening of the intima and media of the vessel wall of large and medium-sized muscular arteries and large elastic arteries, such as carotid arteries2.
Impairment of vascular endothelial function and hypertrophy of the arterial wall are early findings in the development of atherosclerosis that can be assessed non-invasively by high-resolution ultrasound3,4. Flow-mediated dilatation has been known to be endothelial-dependant5. In patients without established atherosclerotic disease, cardiovascular risk factors are associated with impaired endothelial functions and increased intima-media thickness3. Therefore, flow-mediated dilatation of the brachial artery and the carotid intima-media thickness are considered as markers of atherosclerosis6,7.
As prevention and early treatment of atherosclerosis is gaining more attention, these ultrasonographic tests might be used for diagnosis and evaluation of effectiveness of therapy6. Moreover, to maintain a good quality of life in elderly, it is important to diagnose asymptomatic advanced or prone to rupture atherosclerotic lesion by using non-invasive techniques8. High-resolution duplex sonography seems promising for detection, quantification and serial investigations of structural alterations of the arterial wall4.
The aim of the present study is to assess the extent and severity of extra-cranial carotid atherosclerosis as a marker of endothelial function in patients with and without established atherosclerotic disease by using high resolution duplex sonography.
SUBJECTS AND METHODS
This study was conducted on 60 Egyptian patients with evident risk factors for atherosclerosis and 30 normal age and sex matched control subjects Included subjects were distributed into 3 groups:
· Group (A) included 30 patients with clinical evidence of atherosclerotic cerebrovascular event as transient ischemic attacks (TIAs) or ischemic stroke. They were 18 males (60%) and 12 females (40%) ranging in age from 45-69 years with a mean age of 55.5±6.7 years.
· Group (B) included 30 patients with one or more atherosclerotic risk factors without clinical evidence of. cerebrovascular, cardiovascular or peripheral vascular disease. They were 16 males (53.3%) and 14 females (46.7%) ranging in age from 48-70 years with a mean age of 57.9±6.4 years.
· Group(C) included 30 normal healthy subjects age and sex matched to patients. They were 17 males (56.7%) and 13 females (43.3%) ranging in age from 47-70 years with a mean of 57.7±6.7 years.
Methods:
Subjects of the study were subjected to:
I. Thorough clinical assessment: history taking, complete neurovascular and neurological examination was done using the standard cerebrovascular stroke assessment sheet of the Neurology Department, Cairo University.
II. SMART risk score: the Second Manifestations of ARTerial disease (SMART) score was used to evaluate the atherosclerotic risk factors and complications9. A score of 1 point was attributed for each of the following risk factors or vascular diseases:
1. Age: >30 years 1 point for each decade.
2. Male gender.
3. Smoker or ex-smoker.
4. Hyperlipemia or medication for hyperlipemia.
5. Diabetes mellitus or medication for diabetes.
6. Hypertension or medication for hypertension.
7. Body Mass Index (BMI) >30 kg/m².
8. Peripheral arterial occlusive disease or previous interventions on the leg vessels.
9. TIA or stroke; ICA stenosis 50% (detected by angiography or duplex sonography); and previous carotid thromboendarterectomy.
10. Angina pectoris, myocardial infarction.
11. Aortic or renal artery stenosis (detected by angiography or duplex sonography) or impaired kidney function.
The questionnaire was valid when less than three items were unknown or not filled in. Missing items in valid questionnaires were scored as 0. The sum of scores was then calculated for each patient.
III. Laboratory work-up: included fasting & postprandial blood sugar, serum triglycerides, cholesterol, HDL and LDL, uric acid, CRP, CBC, and ESR, kidney and liver function tests.
IV. Electrocardiography and Echocardiography: to detect evidence of myocardial ischemia.
V. Non-contrast Computerized tomography (CT) brain: done to all subjects for the diagnosis of stroke.
VI. High resolution duplex sonographic examination: including; carotid artery duplex, vertebral artery duplex and brachial artery duplex.
Carotid duplex scanning:
(A) B-mode scanning:
- Measurement of intimal medial thickness (IMT): measurements were taken at least one cm below the carotid bifurcation. IMT was measured on the far wall between the leading edge on the intimal line that represents the media adventitia transition.
- Identification of carotid plaque: is present if there was a localized thickening >1.0 mm thick. Continuous thickening was not reported as plaque. The plaques were examined in the transverse and the longitudinal scanning. Plaque score and characteristics were described.
- Plaque score (PS): was calculated according to Nagai et al.10. The common carotid artery (CCA) and internal carotid artery (ICA) on both sides were scanned, the maximum thickness of all plaques found were measured and then the PS was calculated by summing up the thickness of all plaques located in bilateral carotid arteries, it is calculated to be a dimensionless number.
- Plaque characteristics classification: (1) According to the echogenicity into homogenous (uniform) and heterogeneous: (echolucent area(s) was present within the plaque). (2) According to the surface irregularity: into smooth surface, mild irregularities of < 2 mm in depth and mark