Ultrafast pulse wave velocity (UFPWV) is a novel non-invasive method developed recently to evaluate pulse wave velocity (PWV). This multi-center clinical trial aims to evaluate the feasibility of UFPWV in the evaluation of the carotid stiffness of overweight and obese population and investigate the correlation between overweight/obesity and subclinical atherosclerosis, providing an important theoretical basis for early monitoring and risk assessment of carotid atherosclerosis in overweight/obese people.

In recent years, with the change of people's lifestyle and dietary structure, overweight and obesity have become serious problems threatening public health. During 1975-2016, the worldwide prevalence of overweight and obesity increased year by year. By 2016, about 40% of adults were overweight and obese, of which 2.3% of men and 5.0% of women were severely obese (i.e. body mass index ≥ 35 kg/m²). The number of overweight and obese people in China is growing rapidly. Report on the Nutrition and Chronic Disease Status of Chinese Residents (2020 version) shows that over 50% Chinese obese adults have overweight and obesity. Overweight and obesity have become one of the most serious public health problems in China. Previous studies have found that overweight and obesity are often accompanied by abnormalities of blood glucose, blood pressure and blood lipids, leading to dysfunction of vascular endothelial cells and changes in the structure and function of vascular wall, which are closely related to atherosclerosis. Therefore, early detection of atherosclerosis and timely intervention measures can effectively prevent and reduce the occurrence and development of atherosclerosis.

At present, carotid intima-media thickness (CIMT) can be clinically used to evaluate carotid atherosclerosis, which can evaluate the morphological changes of carotid artery, but it cannot be used to evaluate the stiffness of carotid artery. PWV is the gold standard for evaluating arterial stiffness. However, the conventional PWV measurement method can evaluate the stiffness of long-distance artery. Evaluated outcomes are affected by height and body mass, and therefore, the evaluation accuracy of PWV can be limited.

UFPWV is a novel noninvasive method developed in recent years to evaluate PWV. It can be used to evaluate PWV of local artery. Different from the conventional PWV method, UFPWV has a very high frame rate, up to 2000 frames/s, and can track the movement of arterial wall at specific segments in real time. UFPWV can obtain PWV at the beginning and end of systole by tracking and automatic analysis. In recent years, increasing attention has been paid to the role of UFPWV in the evaluation of carotid artery. UFPWV has been used in the study of carotid arteries in normal people, vascular Ehlers-Danlos syndrome, hypertension, hyperlipidemia, diabetes and other groups.

In the early stage, First Hospital of China Medical University participated in the national multi- center, large-sample trial: multi-center study on normal value of ultrafast pulse wave velocity in Chinese Han adults. The center has accumulated rich experience during the project implementation. The center determined the normal reference value of UFPWV for Chinese Han adults and verified that UFPWV has good measurement repeatability. At the same time, the project team had applied UFPWV technology to study early carotid atherosclerosis in patients with metabolic syndrome and coronary slow flow phenomenon. The results show that UFPWV has been accelerated without marked thickening of CIMT, which preliminarily proves that UFPWV can accurately and sensitively detect early carotid atherosclerosis.

This study aims to evaluate the feasibility of UFPWV in carotid stiffness of overweight and obese people, and correlate overweight/obesity with subclinical atherosclerosis, so as to provide an important theoretical basis for early monitoring and risk assessment of carotid atherosclerosis in overweight/obese people.

Inclusion Criteria:

• Han nationality;
• Age ≥18 - 80 years;
• Body mass index ≥ 24 kg/m²;
• Blood pressure ≥ 90/60 mmHg (1 mmHg = 0.133 kPa);
• Fasting blood glucose level ≥ 3.9 mmol/L;
• No abnormality in cardiovascular and respiratory system found by physical examination;
• Normal findings in routine blood test, routine urine test, liver function and kidney function;
• No history of cardiovascular disease, respiratory system disease, liver and kidney disease except hypertension, diabetes or hyperlipidemia;
• Electrocardiogram examination showed no arrhythmia or myocardial infarction;
• No structural cardiac abnormalities (such as moderate or above cardiac valve regurgitation, abnormal ventricular wall motion, congenital heart disease, cardiomyopathy, pericardial lesions) were found by echocardiography, and left ventricular ejection fraction ≥ 53%;
• No marked abnormality in ultrasonography of the liver, gallbladder, pancreas, spleen and kidney;
• Normal findings in carotid ultrasound examination.

Exclusion Criteria:

• Hepatorenal insufficiency;
• Respiratory diseases: Acute or chronic respiratory diseases;
• Large artery diseases: aortic dilatation, aortic dissection, aortic coarctation, multiple Takayasu arteritis, etc;
• Special diseases: history of malignant tumor, acute or chronic infection, moderate to severe anemia, disability or mental disorder, autoimmune diseases, acquired immunodeficiency syndrome, etc;
• Pregnant or lactating women;
• Recent history of surgery and trauma;
• Organ transplant;
• Poor ultrasonic image quality, which cannot meet analysis requirement.

Study population description * (only for observational study): 2400 overweight or obese adults will be recruited from physical examination center. They will be assigned to overweight group (body mass index 24.0-27.9 kg/m²; n = 1200) and obese group (body mass index ≥ 28.0 kg/m²; n = 1200).