The patient was a 74-year-old male who was admitted to the hospital with a 5-day history of sudden onset of pain and chills in the left lower extremity. He had a previous history of cerebral infarction for 7 years, no history of intermittent claudication, and a history of smoking and alcohol consumption. Examination: dry skin of the left foot, bruised skin at the toes, tenderness, low skin temperature below the middle part of the affected limb, palpable fluctuation of the femoral artery, no palpable fluctuation of the N artery, dorsalis pedis artery and posterior tibial artery. Calcification of the wall of the right common iliac artery, 2. limited thinning of the lower segment of the right femoral artery, 3. stenosis of the femoral artery above the middle segment and occlusion below the middle segment of the left lower extremity, occlusion of the N artery, 4. slenderness of the left anterior tibial artery, posterior tibial artery and peroneal artery. He was diagnosed with bilateral lower extremity atherosclerotic occlusive disease, acute arterial thrombosis of the left lower extremity, and old cerebral infarction. On the 4th day after admission, left lower extremity arteriogram was performed and thrombolysis was placed. During the procedure, he saw that the wall of the tortuous iliac artery was not smooth, the left anterior femoral artery was occluded from the opening of the bifurcation and showed a sudden truncation sign, the deep femoral artery could be visualized, the establishment of collateral circulation was poor, and the superficial femoral artery, N artery and distal arterial trunk were not visualized. On the 6th day of admission, the left lower extremity artery was reconstructed and the left anterior femoral artery and the deep femoral artery were visualized, the wall was not smooth and no filling defect was seen. The left N artery was then dilated and thrombolysed. A 5-mm*80-mm balloon was inserted with a pressure pump to dilate the N artery, and a thrombolytic catheter was inserted into the N artery and injected with 500,000 units/day of urokinase for thrombolysis. After the operation, the skin temperature of the affected limb gradually increased and reached the heel, and the toes showed ischemic necrosis, and tension blisters appeared on the dorsum of the foot. The plane of necrosis was gradually revealed. Thrombolytic therapy was administered for 10 days, and the thrombolytic catheter was removed. CT-A of the lower limb artery was repeated: occlusion of the superficial femoral artery, establishment of collateral circulation of the deep femoral artery and N artery, and visualization of the distal calf artery. Discussion: Acute limb ischemia is one of the most challenging topics facing vascular surgeons today, with an annual incidence of about 1,7 cases per 10,000 people. Despite the continuous improvement in surgical techniques and treatment levels, morbidity and mortality rates remain high, with a mortality rate of more than 25% and an amputation rate of more than 20% among survivors. The high mortality rate is often associated with the combination of severe complications. In this case, the patient was of advanced age, with a 7-year history of cerebral infarction and acute occlusion of the long segment of the femoral N artery. Arteriography suggested that the deep femoral artery and the distal artery could not establish adequate collateral circulation, and the literature reported that the distal limb necrosis rate reached 10%~55% after ligation of the superficial femoral artery and 40%~76% after ligation of the N artery. “5P” symptoms, resting pain, skin floridities, cyanosis, sensory and motor impairment appeared. The acute ischemia of the affected limb was long and the ischemic symptoms were severe, and timely treatment was needed to avoid the possibility of necrosis. Fifty years ago, amputation was the only treatment for acute lower limb ischemia, and now arteriotomy and Fogarty balloon catheter embolization have become the traditional surgical treatment for arterial thrombosis. With the rapid development of interventional technology, thrombolytic therapy has been greatly improved, and the application of guidewire technology can make the thrombolytic catheter enter the lesion more selectively, and the multi-lateral thrombolytic catheter can make the long segment thrombus dissolve more efficiently. Exploratory studies on the dosage of thrombolytic drugs have greatly improved the safety and efficacy of treatment, and in the United States, thrombolytic therapy is considered one of the treatment standards for acute arterial obstruction. Patients with severe affected limb ischemia have a very high perioperative mortality rate, and thrombolytic treatment modalities can greatly improve survival. In a study of patients with symptomatic ischemia within one week, the Rochester trial comparing urokinase with surgical treatment found an extremely low mortality rate in the non-surgical group, which was associated with a reduction in perioperative cardiopulmonary complications. Several multicenter studies have shown that thrombolytic therapy is more appropriate for some patients with lower extremity ischemia. The Trial of Thrombolysis Versus Peripheral Vascular Surgery (TOPAS), in which 544 patients were treated with optimal doses of urokinase thrombolysis compared with surgical treatment, yielded no significant difference in the initial conclusions regarding limb preservation, but at one-year follow-up, it was found that the number and duration of re-treatment in patients treated with thrombolysis was greatly reduced, but the odds of bleeding complications were increased, but this did not prolong the patients’ hospital stay and increased mortality. The patient’s ischemic symptoms improved after the operation, and he had intermittent fever after the operation, which was considered to be related to the slow entry of toxin into the blood, and there were no significant abnormalities in renal function and potassium, and no cardiopulmonary complications. 2. Successful thrombolytic treatment still requires the necessary surgical or endoluminal repair treatment after the thrombus is dissolved. Endoluminal repair therapy such as balloon dilation and stenting can be used to treat stenotic lesions after thrombolysis. In this case, the stenosis at the opening of the superficial femoral artery was obvious after thrombolysis, so intervention was given. 3. The use of anticoagulant thrombolytic drugs and their doses. Half of the patients with acute arterial ischemia have various other complications, and serious complications may occur with postoperative reperfusion, and any means of intervention may induce complications, so it is especially important to choose the appropriate treatment plan. Interventional catheter thrombolysis reduces surgical complications and is minimally invasive and effective. It is especially advantageous in elderly and high-risk patients, and needs to be further observed and confirmed in our clinical practice.