Blood vessels are divided into two systems: arterial vascular obstruction mainly manifests as insufficient blood supply and lack of nutritional status, and ischemia of different organs will lead to dysfunction of the corresponding organs.1. Ischemia of the central nervous system manifests as clumsy speech, impaired consciousness, coma or inability to move the contralateral limb.2. Ischemia of the coronary vessels of the heart manifests as angina, panic, chest tightness, shortness of breath, and even heart failure and myocardial infarction.3, 3.Pulmonary artery embolism is manifested as chest pain and difficulty in breathing. 4.Ischemia of limbs is manifested as cold, pain, numbness, ischemia and necrosis, while ischemia of other organs is manifested as insufficiency of the corresponding organs or even functional failure. 5.Thrombosis of the venous system occurs mostly in the blood vessels of the limbs, mainly manifested as reflux obstruction, bruising and swelling of the limbs, swelling, but it has little effect on function.