Limb embolism

Introduction Arterial embolization refers to a pathological process in which the embolus is detached from the heart or the proximal arterial wall, or enters the artery from the outside, pushed to the distal side by the blood flow, and blocks the blood flow of the artery, resulting in ischemia or even necrosis of the limb or internal organs. When the peripheral arteries are embolized, the affected limbs are painful, pale, distant arterial pulsations disappear, cold, numbness, and movement disorders. The onset of the disease is rapid, and the limbs and even the life are threatened after the onset of the disease. It is important to diagnose and count the appropriate treatments every second.

Cause

(1) Causes of the disease

The source of emboli has two categories: cardiogenic and non-cardiac:

Cardiogenic

80% to 90% of peripheral arterial acute embolism is from heart disease, and 2/3 is complicated by atrial fibrillation. Common heart diseases include rheumatic heart disease, coronary heart disease, acute myocardial infarction, cardiomyopathy, congestive heart failure, and postoperative cardiac valve replacement, subacute bacterial endocarditis, and cardiac tumor (atrial myxoma).

(1) Rheumatic heart disease and coronary heart disease are the most common in organic heart disease. The former patients are younger, the ratio of male to female is 1:2; the latter is mostly elderly patients, and the incidence rate of men and women is similar. According to statistics, before the 1960s, rheumatic heart disease was the most common cause of arterial embolism; after the 1960s, coronary heart disease was the main cause, currently coronary heart disease accounted for more than 70%, and rheumatic heart disease was less than 20%. Atrial fibrillation was a high risk factor for peripheral arterial embolization, and approximately 77% of patients with peripheral arterial embolism had atrial fibrillation. According to statistics, chronic atrial fibrillation complicated with acute arterial embolism is 3% to 6% per year, and the incidence of paroxysmal atrial fibrillation and arterial embolism is much lower. Old myocardial infarction is also a risk factor for arterial embolism. Studies have shown that long-term anticoagulant therapy [mainly oral warfarin and/or aspirin] can not only effectively reduce the incidence of stroke, but also significantly reduce the rate of peripheral arterial embolization, regardless of whether or not atrial fibrillation is combined.

(2) Acute myocardial infarction is also a common cause of arterial embolism, most of which occurs within 6 weeks of myocardial infarction. The mortality rate of arterial embolism after myocardial infarction is as high as 50%. Heparin anticoagulation can reduce the incidence of arterial embolism. After myocardial infarction combined with ventricular aneurysm, is another source of arterial embolism, about half of the ventricular aneurysm has a wall thrombosis, 5% with arterial embolism.

(3) In arrhythmia type heart disease, sick sinus syndrome (SSS) is about 16%, complete atrioventricular block is about 1.3% and arterial embolism. Other rare heart diseases that can be complicated by arterial embolization include bacterial endocarditis and prosthetic heart valve replacement. The embolus of bacterial endocarditis (SBE) often embolizes peripheral arterioles, such as the palm, ankle, and toe arteries. In addition to causing arterial embolism and tissue ischemia, it also spreads inflammation, which is bacterial endocarditis. Severe complications, the incidence rate is 15% to 35%; after prosthetic heart valve replacement, 25% of patients will have more than one arterial embolism, and 80% embolization in the brain, 10% of which are fatal, more Seen in those who failed to adhere to lifelong anticoagulant therapy. Partial shedding of the left atrial myxoma can lead to peripheral arterial embolization, but it is very rare.

2. Non-cardiac

Non-cardiac arterial embolism is less common. It mainly includes aneurysms, atherosclerosis with ulcers or stenosis, arterial grafts, vascular injuries, tumors and venous thrombosis.

(1) The wall thrombus of aneurysm is an important source of arterial embolism after heart disease: aneurysms with arterial embolization include abdominal aortic aneurysm, femoral aneurysm, aneurysm and subclavian aneurysm. Aneurysms (25%) and subclavian aneurysms (33%) were most common with arterial embolism.

(2) Atherosclerotic stenosis combined with thrombosis: often occurs in the aorta or iliac artery, the formation of thrombus is larger, the diameter of the embolized artery is also correspondingly larger. Atherosclerotic plaque surface ulcer, cholesterol crystals enter the blood circulation, can also lead to arterial embolization, embolization of the distal diameter of 200 ~ 900m artery, characterized by small embolus, a large number, not only block the peripheral blood vessels after embolization, but also cholesterol After the crystal dissolves into the wall of the tube, it also becomes an inflammatory granuloma, which induces perivascular inflammation and aggravates tissue ischemia. Atherosclerosis cholesterol crystal embolism, often occurs after angiography or endovascular treatment, involving the renal artery, retinal artery, lower extremity peripheral artery. There are no effective treatments for persistent hypertension, renal insufficiency, and "blue toe" or limb blemish. Drug thrombolysis may be effective.

(3) vascular injury: especially the iatrogenic injury factors have a tendency to increase. More common in invasive examination and treatment, thrombosis on the surface of the catheter, and even broken guidewires, catheters, etc., can cause arterial embolism. Other extravascular extravascular injuries, such as the thoracic outlet syndrome, and abnormal neck ribs or first thoracic rib compression of the subclavian artery often produce a wall thrombus that becomes the source of embolism for upper extremity arterial embolism. Long-term walking can also contus the brachial artery and cause wall thrombosis.

(4) Tumor: more common in primary or metastatic lung cancer, the prognosis is very poor.

(5) Venous thrombosis: less common, also known as "paradoxical embolus", is the venous thrombosis that enters the arterial system through the patent foramen ovale or ventricular septal defect. More often associated with pulmonary embolism and pulmonary hypertension.

an examination

Related inspection

Arterial blood gas analysis CT examination of extremities

1. Qualitative diagnosis

Sudden onset of severe limb ischemia, the corresponding arterial pulsation disappeared, that is, there are "5P" signs, accompanied by organic heart disease, arteriosclerosis, especially with atrial fibrillation, recent myocardial infarction or abdominal aorta The patient with the tumor can be diagnosed clearly.

2. Positioning diagnosis

The position where the embolus is blocked can pass:

1 The location of the initial pain.

2 The plane in which the normal pulse disappears, the skin of the skin temperature changes, etc.

3 non-invasive examination (such as Doppler ultrasound, etc.).

4 range of limb circulation disorders.

5 emboli is easy to stay at the arterial bifurcation and other characteristics to determine.

3. Degree diagnosis

According to clinical signs and examination results, acute arterial embolization can be divided into three categories:

(1) mild ischemia: such patients have severe intermittent claudication, and the resting pain is mild. There are often several days from onset to treatment. The signs are free of movement and sensory disturbances except for pale limbs and decreased skin temperature. . There is no secondary thrombus or a small extent at the distal end of the arterial occlusion, and the collateral circulation is abundant. Such patients may have more time to do the corresponding examination and preoperative preparation, according to the specific conditions, consider conservative treatment of anticoagulant thrombolysis.

(2) Moderate ischemia: Most of the clinical patients belong to this category. Resting pain is obvious but can be tolerated. There are mild sensory disturbances. For example, the sensitivity to light touch is reduced, but there is no movement disorder. It is necessary to actively prepare for the operation and timely take the thrombus.

(3) Severe ischemia: loss of sensory and motor function of the affected limb, stiffness of the gastrocnemius muscle, purple spots or blisters on the skin, often requiring amputation to save lives. Some scholars have pointed out that patients with severe ischemia, such as arterial thrombectomy, have a mortality rate of 50% to 75%. If the patient's general condition allows, no renal insufficiency, only limb sensation and motor dysfunction but no muscle stiffness, compartment syndrome and skin purpura, Fogarty catheter thrombectomy is safe and effective for most patients. However, most of the postoperative patients often have sequelae of nerve damage such as numbness and foot drop.

Differential diagnosis

Acute arterial thrombosis

Most of them are secondary to thrombosis on the basis of atherosclerosis, causing acute arterial ischemia. The main points of differential diagnosis are:

1 The onset is not as fast as the arterial embolism, and the plane of the limbs is pale and chilly.

2 There is a history of chronic arterial ischemia, such as intermittent claudication and dystrophic changes caused by insufficient arterial blood supply.

3 angiography showed extensive atherosclerosis, uneven arterial wall, irregular distortion, segmental stenosis or occlusion, and more collateral formation, which coincided with arterial occlusion (Table 2).

2. Acute iliac-femoral vein thrombosis

Severe acute iliac-femoral vein thrombosis, such as femoral bruising, extreme swelling of the limbs on the arteries and strong arterial spasm, can cause arterial blood supply disorders and distal arterial pulsation disappear. However, the clinical manifestations of obvious swelling of the lower extremities, compensatory dilation of superficial veins, normal or slightly elevated skin temperature, are characteristic of deep vein thrombosis and can be distinguished from arterial embolism. Doppler auscultation can clearly detect arterial pulsation, and the / index is usually >0.5.

3. Reduced blood output from the heart

Acute myocardial infarction, congestive heart failure, sepsis, dehydration, and severe trauma can reduce cardiac blood output, increase vasopressin secretion, systemic vasoconstriction, sharp reduction of blood vessels in limbs, cold limbs, and even skin. The plaque and arterial pulsation are weak or disappear. However, in addition to the manifestations of the disease of the heart itself, limbs and colds should involve the limbs at the same time. After anti-shock, recovery of blood volume, and effective control of the primary heart disease, the hypoperfusion of the limb arteries is also relieved.

4. Dissection aneurysms are rare. Aortic dissection aneurysm involving one or both of the radial arteries can cause acute ischemia of the lower extremity arteries. Symptoms of dissecting aneurysms are usually prominent, and patients have symptoms such as high blood pressure, severe back or chest pain.

5. Arterial or femoral aneurysm acute thrombosis

Endovascular thrombosis of the aneurysm leads to occlusion of the lumen, and the pulsatile mass can be seen in the corresponding anatomical site. Double-color ultrasonography can confirm aneurysm and intraluminal thrombosis.

6. Femoral bruises

It is a special and serious type of acute thrombosis of the deep veins of the lower extremities. Extreme swelling of the limbs, bruising, superficial vein dilatation, pulsation of the dorsal and posterior tibial arteries cannot be achieved. But the limbs are still warm.

7. Arterial intimal separation

Arterial intimal separation causes intracavitary pseudosinus compression of the arterial lumen may be accompanied by distal arterial embolization. However, these patients often have chest and back pain, a history of long-term hypertension, auscultation with murmurs, and chest radiographs with mediastinal widening to help diagnose.

In addition, peripheral aneurysm thrombosis, arterial compression syndrome (popliteal entrapment syndrome) and ergotintoxication (ergotintoxication) may cause intermittent claudication, severe ischemic symptoms need to be noted.

Limbs with arterial embolism often have characteristic so-called "5P" signs: pain, numbness, no pulse, paleness, and dyskinesia.

(A) Pain: The main symptoms of most patients are severe pain. Some patients may only feel soreness, and individual patients may have no pain.

(B) numbness, movement disorders: the distal part of the affected limb is a sore-type sensory loss zone, caused by peripheral nerve ischemia. The proximal end has a hyposensitivity zone, and the sensed depression plane is lower than the embolization site.

(C) pale, cold: due to tissue ischemia, blood flow in the subcutaneous venous plexus of the skin is empty, the skin is waxy pale. If a small amount of blood accumulates in the blood vessels, scattered bruising plaques may appear between the pale skin. The circumference of the limb is reduced and the superficial vein is wilting. Fine blue lines appear under the skin, the skin is cold, especially at the distal end of the limb, and the skin temperature can be lowered by 3 to 5 °C.

(4) The arterial pulse disappears or weakens: the arteries at the embolization site have tenderness, and the arterial pulsation disappears or weakens after embolization.

In the case of sudden onset of limb pain with acute arterial ischemia, and corresponding arterial pulsation disappeared, the diagnosis is generally established.

Acute arterial embolization in the absence of collateral circulation compensation will result in signs of acute limb ischemia: Pulselessness, Pain, Pallor, Paresthesia, and Paralysis. , that is, the "5P" sign. The occurrence of these phenomena and their extent are related to the degree of ischemia.

1. Arterial pulsation weakens or disappears

The distal artery that occurs in the segment of the embolized artery. Sometimes due to the impact of blood flow, embolization of the distal artery may touch the conductive pulsation. If the embolization is incomplete, the weakened distal arterial pulsation can be reached. In addition, arterial embolization will also cause tenderness of the affected arteries, which generally occurs at the proximal end of limb ischemia.

The use of ultrasound Doppler stethoscopes or blood flow recorders, which do not smell normal arterial sounds, or the absence of arterial waveforms, is a more reliable method of examination.

2. Pain

After arterial embolization, most patients have severe limb pain that occurs suddenly. The pain site begins at the embolization and later extends to the distal limb of the embolization. The pain site can be displaced, and when the detached embolus rides across the bifurcation of the abdominal aorta, it shows severe abdominal pain; if the embolus is rushed to the femoral artery by blood flow, it becomes a pain in the thigh. The affected limb is tender, and the active or passive activity of the limb can cause pain and is therefore in a state of braking.

3. Pale, skin temperature is lowered

The skin was pale in wax due to a blood supply disorder at the distal end of the embolized artery. If there is still a small amount of blood in the subcutaneous venous plexus, there are cyanosis spots of different sizes on the pale skin color. As a result of reduced blood flow, the superficial veins are collapsed.

The change of skin temperature is related to the site of arterial embolization. When the abdominal aortic bifurcation is embolized, the skin temperature of the buttocks and the lower limbs is decreased. When the radial artery is embolized, the temperature of the ipsilateral thigh is decreased, and the femoral artery is embolized in the middle of the thigh. The following skin temperature decreased, arterial embolization, lower leg and its distal skin temperature decreased. Subclavian artery, radial artery embolization, symptoms involving the entire upper limb; radial artery embolism, symptoms involving the forearm; embolization of the ulnar artery or anterior and posterior iliac artery, due to a rich collateral circulation, symptoms are limited and light.

Skin temperature changes can be detected in the following ways:

1 The examiner touches the affected limb with the dorsal side of the middle middle section of the middle middle finger, and moves from the proximal end to the distal end, and the plane in which the skin temperature of the affected limb is lowered can be perceived.

2 Using the same method to compare the skin temperature of the same plane of the bilateral limbs, it can be found that the skin temperature of the affected limb is lower than that of the non-embolized limb.

3 Using a skin thermometer to measure the bilateral limbs, the degree and plane of the skin temperature reduction can be measured.

4. Feeling and movement disorders

When the peripheral nerve has ischemic damage, a skin sensory loss zone may occur at the distal end of the limb, and the proximal end has a sensory loss zone and a skin sensory sensitive zone. Long embolization time, when there is peripheral nerve damage and ischemic necrosis of muscle tissue, it can cause finger and toe dyskinesia, hand and foot drooping and other symptoms.

The examiner can measure the skin sensation of the affected limb by touching the skin of the affected limb with a hand or by a simple method of acupuncture. The finger or toe of the passively affected limb can be clearly defined as having a deep sensory loss.

5. Tissue necrosis

Once the course of arterial embolization is long, irreversible tissue ischemic necrosis will eventually occur. In addition to the dry necrosis of the fingers or toes caused by terminal arterial embolization, the tissue necrosis of the main artery is extensive, the limbs are cold, the color is dark purple, and the network is cyanotic; the skin appears blisters, containing bloody exudate; tissue thickening ,Stiff. At this time, there are obvious systemic symptoms: scorpion, high fever, chills, heart rate, and even blood pressure.

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