Lower extremity artery embolism refers to a pathological process in which an embolus is dislodged from the heart or proximal artery wall, or enters the artery from outside and is pushed to the distal side by the blood flow, blocking the blood flow of the lower extremity artery and causing limb ischemia or even necrosis. In lower limb artery embolism, a series of clinical symptoms such as pain, pallor, loss of distal arterial pulsation, coldness, numbness and motor impairment appear in the affected limb.
Etiology.
1, cardiogenic: 80-90% of acute limb artery embolism originates from the cardiovascular system, with rheumatic heart disease and coronary artery disease being the most common. Atrial fibrillation and recent (<4 weeks) myocardial infarction with intramural thrombus are the two main sources of emboli.
2, vascular origin: emboli mostly come from the aorta and the wall thrombus of iliac and N artery aneurysm, the wall thrombus of arterial wall inflammation, atherosclerotic plaque and the endothelial flip or detachment after arterial wall injury in case of trauma.
3, medical origin: emboli mostly come from the endothelium or sclerotic plaque dislodged during surgery or intracavitary treatment, and the end of the catheter guidewire is broken. In addition, after the artificial heart valve replacement, the anticoagulant drug dosage is insufficient especially and, other: malignant tumor breaks into the artery to become embolus is a relatively rare clinical cause. In another 5% of patients, the source of the embolus cannot be determined.
Clinical manifestations.
”5P” signs: sudden pain, pulselessness, abnormal sensation, pallor and dyskinesia.
Ancillary tests.
1.Dermal temperature measurement: generally the embolism site is located at the position about 10cm above the skin becoming warm.
2.Ultrasound: It can accurately make the localization of embolism, facilitate preoperative and postoperative comparison, understand the reconstruction of blood vessels and detect the patency of blood vessels. Its disadvantage is that the experience and level of the examiner have some influence on the results.
3.Arteriography: Arteriography is the gold standard of embolism diagnosis and localization. In practice, most patients can be diagnosed based on clinical symptoms and signs as well as ultrasound. Arteriography is performed only when there is doubt in the diagnosis.
4. After the diagnosis is confirmed, chest X-ray, electrocardiogram and echocardiogram are done accordingly to understand whether there is arrhythmia and recent myocardial infarction, to achieve further identification of the cause of arterial embolism for timely treatment and control of the cause.
Treatment.
1.Non-surgical treatment
(1) Local treatment of the limb The affected limb is placed in a position lower than the heart plane, usually about 15 cm down, to facilitate blood flow into the limb. Room temperature is kept at about 25℃. Local hot compresses should not be used to avoid increased tissue metabolism and aggravation of ischemia and hypoxia in the affected limb. Local cold compresses and cooling can cause vasoconstriction and reduce blood supply, and are contraindicated.
(2) Anticoagulation therapy Subcutaneous injection of low molecular heparin 5000 units twice a day, systemic heparinization should be used for 3-5 days in the acute stage.
(3) Thrombolytic therapy Urokinase is injected directly by puncture or via catheter into the lumen of the artery proximal to the embolus. It can also be applied via intravenous drip.
(4) Vasoactive drug therapy 0.1% procaine 500-1000ml intravenously, once/day, to relieve vasospasm. 30-60mg of poppine is injected directly into the lumen of the artery proximal to the embolus, and can also be injected intravenously or intramuscularly. Prostaglandins in appropriate doses have vasodilating effects in addition to inhibiting platelet coagulation.
2.Surgical treatment
Emergency embolization surgery is the preferred treatment method. Different techniques can be used for different locations of embolus obstruction. The number of patients with arterial embolism caused by atherosclerosis and coronary heart disease is gradually increasing, and such patients often have both lower limb arterial sclerosis and stenosis. It is recommended that intraoperative angiography should be performed routinely for each procedure, so that a detailed assessment of the vascular condition can be made before and after embolization, and a preliminary prognosis of the effect of embolization can be made. For the problems found in the angiogram, intraoperative techniques such as endarterectomy, artificial vessel bypass, balloon dilation of the stenotic occluded segment, and stent implantation can be used to further repair the diseased artery to ensure good surgical results and exclude residual emboli and secondary thrombosis. If irreversible necrosis of the limb has clearly occurred preoperatively, it suggests that the affected limb is difficult to be salvaged and should be amputated directly instead of attempting to restore blood flow. Because once the blood flow is restored, the necrotic limb produces a lot of toxic substances into the blood circulation, which will cause serious consequences to the organism.
3.Treatment of primary disease
After removing the embolism, the cause of embolism should be actively identified, and further treatment should be made for the original disease.