Acute lower extremity ischemia is present in atherosclerotic occlusive disease, thrombo-occlusive vasculitis, vasculitis, arterial injury, arterial distress, and arterial epicardial cystic disease. Comprehensive domestic and foreign data, smokers account for 60-95% of patients with acute lower extremity ischemia. So when suffering from this disease, what tests need to be done? Let’s learn more about the following: Skin temperature measurement under certain room temperature (15-25℃), the limb temperature decreases by more than 2℃ compared with the corresponding part of the opposite side, indicating that the blood supply to the limb is insufficient. Cardiovascular angiography: Cardiovascular angiography is one of the most important means of diagnosing cardiovascular diseases. It is a relatively complex and special examination method with certain risks and requires strict control of indications. 1. Right heart angiography (1) Preoperative definite diagnosis of congenital heart disease. (2) To determine the nature of the heart murmur in order to guide the treatment. (3) Re-appearance of symptoms after cardiac surgery and the need for reoperation. 2. Left heart angiography (1) Mitral stenosis or incomplete closure. (2) Aortic stenosis or insufficiency. (3) Congenital heart disease. (4) Primary cardiomyopathy. (5) Left ventricular ventricular wall tumor, etc. ECG: The heart is excited by the pacing point, atria and ventricles successively in each cardiac cycle, accompanied by bioelectric changes, and the graph of various forms of potential changes (abbreviated as ECG) is elicited from the body surface through an electrocardiographic tracer. ECG is an objective indicator of the process of occurrence, propagation and recovery of cardiac excitation. ECG is the earliest, most commonly used and basic diagnostic method in the diagnosis of coronary artery disease. Color ultrasound and arteriography should be performed prior to surgical treatment. When applying advanced digital imaging arteriography and angiography we can find that arterial ischemia of the lower extremities is mainly due to occlusion of the main arteries of the lower extremities. The cause of occlusion can be either atherosclerotic plaque or thickening of the vessel wall and thrombotic blockage. The site of occlusion can occur in the lower abdominal aorta as well as in the femoral and popliteal arteries. The higher the site of arterial occlusion, the larger the area of ischemia; the lower the site of occlusion, the earlier the onset of ischemic symptoms.