atherosclerosis
Introduction
Introduction Atherosclerosis is the most common type of vascular disease in a group of arteriosclerosis, characterized by affected arterial lesions starting from the intima. Generally, there are lipid and complex carbohydrate accumulation, hemorrhage and thrombosis, fibrous tissue hyperplasia and calcinosis, and gradually gradual metamorphosis and calcification of the middle layer of the artery. The lesion often involves elasticity and large and medium muscular arteries, once developed enough to block In the arterial lumen, the tissue or organ supplied by the artery will be ischemic or necrotic. Since the appearance of lipids accumulated in the intima of the artery is yellow atheroma, it is called atherosclerosis.
Cause
Cause
Although the cause of atherosclerosis is not fully understood, it is known to be closely related to the following factors (susceptibility factors):
First, high blood pressure
Clinical and autopsy data indicate that the incidence of atherosclerosis is significantly increased in patients with hypertension. This may be due to the high pressure of the arterial wall, the damage of the intimal layer and the endothelial cell layer, the low density lipoprotein easily enters the arterial wall, and stimulates the proliferation of smooth muscle cells, causing atherosclerosis.
Second, hyperlipidemia
Clinical data suggest that atherosclerosis is common in hypercholesterolemia. Experimental animals given high cholesterol diet can cause atherosclerosis. Recent studies have found that the increase of low density lipoprotein and extreme density lipoprotein and the decrease of high density lipoprotein are related to atherosclerosis. The increase in blood triglycerides is also related to the occurrence of atherosclerosis. Recent studies have found that lipoprotein a [Lp(a)] is closely related to the occurrence of atherosclerosis.
Third, smoking
The concentration of carboxyhemoglobin in the blood of smokers can reach 10-20%, the oxygenation in the arterial wall is insufficient, the synthesis of fatty acids in the intimal layer is increased, the release of prostacyclin is reduced, and platelets are easily adhered to the arterial wall. In addition, smoking can also reduce the amount of pro-protein of high-density lipoprotein in the blood, and increase the serum cholesterol level, so that it is prone to atherosclerosis. In addition, the nicotine contained in the smoke during smoking can directly affect the arteries and myocardial damage caused by the heart and coronary arteries.
Fourth, diabetes
People with diabetes are often associated with hypertriglyceridemia or hypercholesterolemia. If accompanied by hypertension, the incidence of atherosclerosis is significantly increased. People with diabetes often have elevated blood factor VIII and increased platelet activity. Factor VIII is produced by cells in the arterial wall. The increase in this factor indicates lesions of the intima. Increased platelet activity makes it easy to accumulate on the arterial wall, accelerate atherothrombotic thrombosis and cause occlusion of the arterial lumen. In recent years, studies have concluded that insulin resistance is closely related to the occurrence of atherosclerosis. Patients with type 2 diabetes often have insulin resistance and hyperinsulinemia associated with coronary heart disease.
Five, obesity
It is also a predisposing factor for atherosclerosis. Obesity can lead to increased levels of plasma triglycerides and cholesterol. Obese people are often associated with hypertension or diabetes. In recent years, obesity patients often have insulin resistance, and the incidence of atherosclerosis is significantly increased.
Six, genetic factors
The incidence of AS in patients with familial hypercholesterolemia and familial lipoprotein lipase deficiency was significantly higher than that in the control group, suggesting that genetic factors are risk factors for AS.
Seven other factors
(1) Age: The severity of AS detection rate and severity of lesions increased with age and was associated with age changes in the arterial wall.
(2) Gender: Women's premenopausal HDL levels are higher than men's, LDL levels are lower than men's, and the risk of coronary heart disease is lower than that of men of the same age group. After menopause, the difference in incidence between the sexes disappears.
(3) Being overweight or obese.
(4) Infection: Some experiments have reported that some viruses may be involved in AS.
Examine
an examination
1, patients often have elevated blood cholesterol, triglycerides, high-density lipoprotein decreased, lipoprotein electrophoresis pattern abnormalities, most patients with type III or type IV hyperlipoproteinemia.
2, X-ray examination shows aortic elongation, expansion and distortion, sometimes visible calcium deposition.
3, angiography can show the stenosis, lesions and extent of the quadriple artery, renal artery and coronary artery caused by atherosclerosis.
4, Doppler ultrasound examination helps to determine the blood flow of the arteries and renal arteries of the extremities.
Diagnosis
Differential diagnosis
1. Patients over the age of 40, if there is a widening of the aorta, can rule out other diseases, suggesting the possibility of aortic atherosclerosis.
2. If there is sudden vertigo or gait instability without signs of increased intracranial pressure, there should be suspected cerebral insufficiency caused by basilar atherosclerosis.
3. After the event, there is a brief post-sternal and precordial pain or pressure in the anterior region, and the coronary artery insufficiency should be suspected.
4. Nocturia is often one of the early symptoms of renal atherosclerosis.
In addition, patients are often associated with susceptibility factors such as hypertension, hypercholesterolemia, hypoHDL, diabetes, and smoking. Such as selective electrocardiogram, radionuclide heart, brain, kidney and other organ scans, Doppler ultrasonography, and selective angiography, etc., can help to confirm the diagnosis. Clinically, it is often necessary to distinguish between inflammatory arterial lesions (such as multiple arteritis, thromboembolic vasculitis, etc.) and congenital arterial stenosis (such as aorta, renal artery stenosis, etc.). Inflammatory arterial diseases often have low fever, increased erythrocyte sedimentation rate and other inflammatory manifestations. Congenital aortic coarctation is mild in age and is not accompanied by susceptibility factors of atherosclerosis.
