Augmented Velocity Index of Intra-abdominal, Carotid and Retinal Arteries

Study Overview
=================
Brief Summary
-----------------
Background: Augmented Velocity Index (Avi) is a new Doppler index which can potentially be used to assess arterial stiffness. The Avi of common carotid artery is found to be associated with arterial stiffness and have initial correlation with cardiovascular risk factors. Avi can be used in any vessels (superficial or deep vessels) where arterial Doppler waveforms can be obtained. Aims: The aims of this study are to investigate the associations of Avi of hepatic artery, renal artery, central retinal artery and internal carotid artery with arterial stiffness and cardiovascular risk factors in a group of apparently normal subjects. Methods: Recruit 350 subjects with no known medical illness or drug treatment for ultrasound examinations and blood tests. In ultrasound examination, the Avi of carotid arteries, hepatic arteries, renal arteries and retinal arteries are recorded. The carotid-femoral pulse wave velocity is also calculated for the assessment of central aortic stiffness. Other important correlates of arterial stiffness including carotid intima-media thickness, fatty liver status, liver stiffness and abdominal fat thickness are assessed in the ultrasound examination. The clinical and laboratory examinations include anthropometric indexes, plasma glucose level, lipid profile, renal function tests, liver function test, urinary albumin creatinine ratio, blood pressure measurement.

Official Title
-----------------
Augmented Velocity Index of Intra-abdominal, Carotid and Retinal Arteries: In Relation to Arterial Stiffness and Cardiovascular Risk Factors.

Conditions
-----------------
Arterial Stiffness

Intervention / Treatment
-----------------
* Diagnostic Test: Ultrasound derived Avi


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Apparently healthy volunteers Exclusion Criteria: Subjects with known medical illnesses including cancer, stroke, cardiovascular disease, diabetes, hypertension, dyslipidaemia, peripheral vascular disease, gout, systemic lupus erythematosus, psoriasis, rheumatoid arthritis and thyrotoxicosis. Subjects with long term drug use

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 70 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Intervention/Treatment |
| --- |
|Diagnostic Test: Ultrasound derived Avi|Assess the Avi of carotid arteries, hepatic arteries, renal arteries and central retinal arteries.|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Augmented Velocity Index (Avi) | Avi of carotid, renal, hepatic and retinal arteries as recorded from the Doppler ultrasound waveforms of those arteries | Aug 2022 - May 2024 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Arterial wall thickness, liver stiffness and fatty liver status | Intima-media thickness of carotid artery is measured in gray scale ultrasound images; Liver stiffness is assessed by shear wave elastography of ultrasound technique; Fatty liver status is determined by the attenuation imaging of ultrasound | Aug 2022 - May 2024 |