Lower extremity atherosclerotic occlusive disease With the change in the structure of the domestic diet (increased intake of fat-containing foods), the increase in life expectancy and the improvement of examination and diagnostic techniques, there is a tendency to increase the number of patients diagnosed with lower extremity atherosclerotic occlusive disease. Atherosclerotic occlusive disease is a large and medium-sized atherosclerotic vascular disease that develops mostly in middle-aged and elderly men. The cause of the disease is unknown, but it is associated with hyperlipidemia, hypertension, diabetes mellitus, low high-density lipoprotein, obesity, hypercoagulable state of blood, smoking, genetics and other factors. Early in the lesion, the intima of the artery is subjected to infiltration of plasma lipoproteins and lipid deposition, producing fatty streaks. Further, intimal hyperplasia and atheromatous plaque formation occur. Ultimately, arterial stenosis is formed, or the artery is blocked. The initial progression of the lesion is slow and may be asymptomatic, and as it progresses, acute or chronic limb ischemic manifestations may occur. All the aorta of the body can be involved, but mostly in the abdominal aorta, iliac artery, femoral artery, etc. The upper limb arteries are rare. The main clinical manifestations are coldness, numbness, pain, intermittent claudication of the affected limb, loss of arterial pulsation, nutritional disorders of the limb tissues, and ulceration or gangrene of the toes or feet. 1, etiology Although the ultimate cause has not been confirmed, many patients with atherosclerosis-occlusive disease have higher than normal hypertension, total blood cholesterol, triglycerides and β-lipoprotein, especially in recent years, it was found that patients with lower limb atherosclerosis-occlusive disease have decreased high-density lipoprotein and increased low-density lipoprotein, suggesting that disorders of lipid metabolism are closely related to the occurrence and development of this disease. In addition, the occurrence of atherosclerosis-occlusive disease is more frequent in diabetic patients than in those without diabetes, and it makes atherosclerosis occur early and to a serious degree. In addition, increased blood coagulation can aggravate atherosclerotic occlusions. Statistical studies have found a relationship between smoking and the occurrence and development of atherosclerotic occlusions. Smoking is twice as harmful to peripheral blood vessels as cardiovascular and cerebrovascular, and smoking cessation can improve clinical symptoms and slow down the progression of the disease. 2, epidemiology With the improvement of the overall living standard and the aging of the population, the incidence of lower extremity atherosclerosis and lower extremity atherosclerosis occlusive disease will be more and more patients, the latest statistical results show that there are 12 million patients with lower extremity atherosclerosis occlusive disease throughout the United States. The TASC published a lower extremity atherosclerosis occlusive disease survey results show that the incidence of lower extremity atherosclerosis occlusive disease in men aged 40 to 50 years is 0.3% per year, and the incidence of lower extremity atherosclerosis occlusive disease in elderly people aged 75 years or older increases by 1%. A population-based survey in Australia showed that the prevalence of lower extremity atherosclerotic occlusive disease in men aged 65-69 years was 10.6%, while the prevalence of lower extremity atherosclerotic occlusive disease in those aged 75-79 years was as high as 23.3%. A population-based survey by the Framingham Cardiovascular Research Centre showed that 20% of symptomatic PDA in lower extremity atherosclerotic occlusive disease suffered from Diabetes mellitus, compared with the non-sugar shit patient population, has a higher prevalence of lower extremity atherosclerosis occlusive disease, a younger age of disease, and a faster progression of disease. 3.Pathogenesis The pathogenesis of atherosclerosis in lower limb atherosclerosis is complex and is a process of long-term comprehensive action of multiple factors. The endothelial cells of the arterial wall are damaged, their function is changed and their permeability is increased. Mononuclear cells in the blood adhere, infiltrate and enter the subendothelium, phagocytose lipids into foam cells and form fatty plaques, platelet aggregation also adheres and activates locally, phagocytes, endothelial cells and platelets adhering to endothelial cell damage release growth factors to stimulate smooth muscle cells to enter the endothelium and proliferate, and fatty plaques become fibrous plaques, eventually The result is atherosclerosis lower limb atherosclerosis occlusive disease. Atherosclerosis of the lower extremity mainly involves the large elastic arteries and medium-sized myoelastic arteries of the body circulation system, and peripheral vascular lesions are common in the lower extremity arteries. The lesions of diabetic lower extremity atherosclerosis occlusion are relatively special, the involvement of anterior tibial, posterior tibial and peroneal arteries is common, the atherosclerotic changes in the vessel wall are not obvious, the clinical symptoms of lower extremity atherosclerosis occlusion are mostly caused by thrombosis. 4.Pathology The development of this disease is often progressive, the atherosclerotic intima can be ulcerated and bleeding, secondary to thrombosis, resulting in luminal narrowing or complete occlusion, so that the tissue supplied by the artery develops ischemia. The site of occlusion is high and the area involved is wide. If the occlusion occurs faster and the collateral circulation fails to compensate in time, the ischemia is more severe and the range of tissues involved is wider. On the contrary, if a limited occlusion occurs slowly at the distal end of the artery, the abundant collateral circulation can fully compensate, the tissue does not produce significant ischemia, and the clinical symptoms are mild or non-existent. After chronic ischemia of the limb tissue, skin atrophy and thinning, loss of subcutaneous fat replaced by fibrous connective tissue, bone thinning, muscle atrophy, and ischemic neuritis occur, leading to gangrene when tissue ischemia becomes so severe that the tissue cannot obtain the oxygen content necessary to maintain viability. Gangrene in the limb often begins at the end and can be confined to the toes or extend to the foot or lower leg, rarely extending beyond the knee joint. Tissues of diabetic patients are more susceptible to damage and infection when the degree of ischemia is the same. 5. Clinical manifestations The age of onset of the disease is mostly between 50 and 70 years old. Male patients are more common than female patients, and only about 20% of female patients. The earliest symptoms of the disease are coldness, numbness and intermittent claudication of the affected limbs. If occlusion occurs in the lower abdominal aorta or iliac artery, there is soreness, weakness and pain throughout the buttocks and lower extremities after walking, and if the symptoms occur in the lower legs, it suggests a possible femoral artery occlusion. As the disease progresses, the ischemia of the affected limb worsens, and persistent resting pain may occur in the toes, foot or lower leg in a quiet state, more intense at night, and the patient often sits with his feet in his arms and stays awake all night. The affected toes, feet or calves have pale complexion, decreased temperature, decreased sensation, thinning skin, muscle atrophy, thickened and deformed toenails, and sparse bone. Severe ischemia produces ulcers and gangrene in the toes, feet, or lower legs. Especially in patients with combined diabetes is more likely to produce, and easy to evolve into wet gangrene and secondary infection, can occur at the same time the symptoms of systemic toxicity. 6, clinical staging According to the severity of symptoms, the clinic is divided into four stages. Stage I: The affected limbs are slightly cool or mildly numb, and easily feel fatigue after activity. There are no obvious symptoms of lower limb ischemia. Stage II: Intermittent claudication appears when walking. Stage III: Resting pain, i.e. pain even without walking. Stage IV: Ulceration or necrosis of the extremity, decreased skin temperature and dull sensation. If combined with diabetes mellitus, the chance of necrosis of toe and lower leg increases, and it is easy to combine with infection. 7.Imaging information The imaging diagnosis methods of lower limb arterial occlusive disease mainly include lower limb arteriography, lower limb artery ultrasound, lower limb artery CTA and lower limb artery MRA, etc. Angiography is the “gold standard” for the diagnosis of lower extremity arteriosclerosis occlusive disease, and can accurately show the location, degree of stenosis/occlusion, collateral circulation, and hemodynamic changes of lower extremity arteriosclerosis occlusive disease, but because it is invasive, complicated, and easy to cause pain, lower extremity arteriogram is mostly used for surgery or intervention. Before revascularization. Lower extremity arteriosclerosis occlusive disease ultrasound is the most important screening test to diagnose lower extremity arteriosclerotic disease, with the advantages of safety, non-invasive and inexpensive. It reflects the location and degree of lower extremity arterial occlusion in lower extremity atherosclerotic occlusive disease with high accuracy, and also allows qualitative and quantitative analysis of lower extremity atherosclerotic occlusive disease. However, ultrasound cannot visualize the whole picture of the lower extremity atherosclerotic occlusive disease lesioned vessels and its sensitivity and reliability are also affected by the operator’s proficiency, probe pressure and sound beam direction. The ability of CTA of lower extremity arteries to find distal segments of occluded arteries is better than conventional angiography, the shortcomings include small layer thickness, making the amount of information increase causing reading difficulties, lower extremity atherosclerosis occlusion MRA is a non-invasive vascular examination, no radiation damage easily accepted by patients, but its relatively low image clarity and high false positive rate limit its clinical application of lower extremity atherosclerosis occlusion. 8.Laboratory examination 8.1 Blood lipid examination Increased blood lipid or decreased high-density lipoprotein often indicates the possibility of atherosclerotic lesions, but normal blood lipid and high-density lipoprotein cannot exclude their existence, so the determination of total cholesterol, triglyceride, beta lipoprotein and high-density lipoprotein only has reference value for diagnosis. 8.2 Blood glucose, urine glucose, blood count and red blood cell pressure measurement The purpose is to understand whether the patient has concomitant diabetes mellitus or erythrocytosis. 9.Electrocardiogram The purpose is to find out whether the patient has concomitant coronary atherosclerotic heart disease, which is quite important for estimating the risk of surgery. 10.Treatment The treatment of lower extremity atherosclerosis occlusive disease such as internal hypotension, lipid lowering and antiplatelet aggregation can only delay the progress of lower extremity atherosclerosis occlusive disease, but cannot fundamentally eliminate the narrowing and occlusion of lower extremity atherosclerosis vessels. 10.1 Surgical treatment Surgical endovascular debridement, artificial vessel replacement, bypass reconstruction surgery, etc. for lower limb atherosclerosis occlusive disease 10.2 Endovascular interventional treatment for lower limb atherosclerosis occlusive disease: Endovascular interventional treatment for lower limb atherosclerosis occlusive disease has the advantages of minimally invasive, simple operation, precise efficacy and repeatable operation, which is the development direction of diagnosis and treatment of vascular diseases. 10.2.1 Percutaneous balloon angioplasty (PTA) for lower extremity atherosclerosis occlusive disease PTA for lower extremity atherosclerosis occlusive disease is a major advancement in the treatment of vascular diseases, and at present, balloon angioplasty (BaHoon Angioplasty) for lower extremity atherosclerosis occlusive disease is a relatively mature technique. The main mechanism of vasodilatation in lower extremity atherosclerosis-occlusive disease PTA is that the balloon dilates and separates the narrowed and sclerotic intima, while destroying the strong layer of smooth muscle and collagen fibers in the intima. It causes the atherosclerotic plaque to fracture and the intima to stretch, thus balloon vasodilation is a mechanical expansion leading to vascular remodeling for the treatment of lower extremity atherosclerosis occlusive disease. 10.2.2 Lower extremity atherosclerosis occlusive disease endovascular stent (Stent) In lower extremity atherosclerosis occlusive disease PTA can lead to vascular entrapment tear and elastic retraction, while stent implantation overcomes the two main defects of PTA by squeezing the plaque and compressing the vessel wall, and is a new endoluminal treatment for lower extremity atherosclerosis occlusive disease. 10.2.3 Lower Extremity Atherosclerosis Occlusive Disease Endoluminal Sclerotic Plaque Cyclotomy (PAC) This technique for lower extremity atherosclerosis occlusive disease began in the mid-1980s. The principle is to use a high-speed rotating device to grind atheromatous plaque into very fine particles, and the crushed atheromatous plaque debris and particulate particles can be engulfed by the reticuloendothelial system without causing distal vessel blockage. Theoretically, atherosclerotic plaque spinotomy for lower extremity atherosclerosis can remove the calcified hard plaque from the vessel wall without damaging the vessel wall. 10.2.4 Ultrasound and laser angioplasty for lower extremity atherosclerosis-occlusive disease are the newest hot spots of peripheral interventional techniques for lower extremity atherosclerosis-occlusive disease in recent years, which can open long segments of occluded lesions of smaller arteries and are especially suitable for the treatment of occluded lesions below the diabetic rouge artery. 10.2.5 Thrombolysis of skeletal arteries in lower extremity atherosclerosis occlusive disease