The Atherosclerosis Index is calculated by subtracting HDL from total plasma cholesterol and dividing by HDL, and the normal value should be less than 4. If the Atherosclerosis Index is less than 4, it means that the degree of atherosclerosis is relatively mild and the probability of cardiovascular disease is relatively low. If the atherosclerosis index is greater than or equal to 4, it means that atherosclerosis has occurred, and the incidence of cardiovascular disease will be relatively high. Vessels prone to atherosclerosis include the aorta, coronary arteries, cerebral arteries, renal arteries and lower limb arteries, and common diseases include coronary atherosclerotic heart disease, which is divided into angina pectoris and myocardial infarction; cerebral atherosclerosis is prone to cerebral infarction, accompanied by hypertensive disease and also prone to cerebral hemorrhage; lower limb atherosclerosis is prone to lower limb atherosclerosis occlusive disease.