Arteriosclerotic occlusive disease is most commonly seen in middle-aged and elderly patients, mainly due to atherosclerosis, and a few are diabetic patients. Arteriosclerotic occlusive disease is a systemic disease that occurs in large and medium-sized arteries, such as the abdominal aorta, iliac artery, femoral artery and N artery, etc. It can also involve the carotid artery, and rarely occurs in the upper limb arteries. The branches of the arteries are the most common sites of thromboembolic disease. Stenosis or occlusion of arteries leads to reduced blood flow in the distal part of the narrowed or occluded artery, causing symptoms of insufficient blood supply to the corresponding organ or limb.
[Etiology].
The cause of arteriosclerotic occlusive disease is not well understood, but most patients are obese and have a history of excessive fat intake, and their blood cholesterol, triglycerides and lipoproteins are also increased, so the disease is associated with increased blood lipids. A significant proportion of patients suffer from hypertension, so it is believed that hypertension is one of the predisposing factors for this disease. The action of nicotine and nicotine can cause spasm of peripheral blood vessels, so it is believed that smoking is associated with atherosclerosis. In diabetic patients, atherosclerosis due to abnormal fat metabolism has an early onset and is more widespread than general atherosclerosis and can involve the small arteries of the lower extremities, predisposing them to ulceration and gangrene and to secondary infection. Therefore, the etiology of atherosclerotic occlusive disease is multifaceted and multifactorial.
Pathology
Atherosclerotic occlusions occur at the bifurcation of arteries, such as the end of the abdominal aorta, the branches of the internal and external iliac arteries, and the bifurcation of the common femoral artery and N artery, because vortexes are easily formed at the bifurcation, resulting in intimal damage.
In the early stages of the disease, intimal lipid deposition is observed, followed by intimal hyperplasia and atheromatous plaque formation. Degeneration of the elastic fibers in the middle layer of the artery occurs, but rarely encroaches on the outer artery membrane. Calcium then deposits on the atheromatous plaque, making it larger and stiffer. As the atheromatous plaque increases in size and protrudes into the lumen, it reaches a certain level and affects the passage of blood flow, generating vortices. Subsequently, thrombosis occurs and the arterial lumen may be completely occluded. Detachment of atheromatous plaque can lead to acute embolization of the distal artery. As a result of degeneration and loss of elasticity of the elastic fibers and thinning of the muscular layer, the artery can dilate and form an aneurysm under the constant impact of arterial pressure. The outer membrane of the artery generally remains intact, and there is often a peelable gap between it and the middle layer of the artery, making endarterectomy possible. Atherosclerotic occlusive disease is often segmental or may develop bilaterally.
Atherosclerotic occlusions below the abdominal aorta can be divided into four types according to the site of stenosis or occlusion.
(i) Pelvic type: about 20%, with the main lesions located in the main abdominal and iliac artery segments.
(ii) Femoral type: about 50%, with the main lesions in the femoral and N artery segments.
(iii) Peripheral type: about 17%, with lesions mostly below the N artery.
(iv) Mixed type: extensive and multiple lesions.
Since the progression of stenosis and occlusion is slow, there is collateral circulation formation. As the stenosis worsens, the collateral branches increase gradually. In the case of stenosis or occlusion of the abdominal aorta or iliac artery, branches of the intercostal artery, lumbar artery, lumbar iliac artery, superior gluteal artery, and deep rotor iliac artery can participate in the collateral circulation and anastomose with branches of the deep femoral artery, and the collateral circulation is richer and can compensate for blood supply. Although these lateral branches cannot fully compensate and clinical symptoms of limb ischemia appear, they rarely cause obvious manifestations of acute limb ischemia. Gangrene of the extremity does not usually occur either. In the peripheral type, the arterial branches around the knee can also form collateral branches, but they are not as abundant as the above-mentioned collateral circulation and have a poorer compensatory function, which can lead to gangrene of the extremity.
Clinical manifestations]
The average onset of atherosclerotic occlusive disease is older, mostly over 50 years of age. There are significantly more male patients than female. In the early stage of the disease, patients only have a mild feeling of coldness and mild numbness in the affected limb, and they feel easily tired after activity. As the lesion continues to worsen, the symptoms also worsen, and the characteristic symptoms of arterial insufficiency of the lower extremities – intermittent claudication – appear, with the symptoms of the lower legs being more severe than those of the thighs. If the lateral circulation is insufficient, resting pain, i.e., pain, numbness and abnormal sensation in the affected limb even at rest, may appear. If the disease continues to worsen, gangrene of the extremity may develop. In patients with atherosclerotic occlusion of the pelvic type, there is often intermittent claudication of the lower back, buttocks, thighs, and calf muscles, except for a weakened or absent femoral artery pulsation, and rarely a nutritional disorder of the extremities. This type is also known as Leriche syndrome.
On examination, the arterial pulsation below the stenotic or occluded segment is diminished or absent, Buerger’s sign is positive, and the dorsalis pedis venous filling time is prolonged. The filling time of the dorsalis pedis depends on the degree of stenosis and the number of collateral branches. The skin temperature of the distal extremity is decreased, the muscles are atrophied, and the sweat hair is sparse. Vascular murmurs can be heard in the area of arterial stenosis.
The presence of resting pain for more than 2 weeks, ankle artery pressure ≤6.7kPa (50mmHg), toe artery pressure ≤4.0kPa (30mmHg), or ankle/brachial ratio ≤0.5, is considered chronic critical lower limb ischemia (chronic critical leg ischemia), and the amputation rate is high.
Auxiliary examination
The main feature of this disease is that it occurs mostly in middle-aged and elderly people, and most of the patients are male. It is not difficult to make a diagnosis based on the history and physical examination, and the plane of occlusion can be determined based on palpation and auscultation of the pulse.
1, laboratory tests: most patients have increased blood lipids, diabetic patients have increased blood glucose, urine glucose, blood rheology examination mostly abnormal and hypercoagulable state.
2.Doppler ultrasound: general Doppler ultrasound examiner can measure the intensity of arterial pulsation and blood flow velocity. Advanced multi-functional Doppler ultrasonography can show the lesion site and the degree of lesion of the artery, which provides strong supporting evidence for clinical diagnosis and treatment, and is therefore the preferred clinical examination means.
3.Electrocardiogram: It can indicate whether the heart has accompanying lesions.
4.Nuclear flow diagram: It can show the lesion site of the involved artery.
5.Arteriogram: Arteriogram can determine the site and scope of the lesion and its surrounding collateral circulation, which can help in the formulation of treatment plan and the selection of operation style.
Treatment
I. Non-surgical treatment
Non-surgical treatment includes vasodilation, expectoration, snake venom products and other drugs and herbal treatment, as well as sympathetic nerve closure, hyperbaric oxygen chamber therapy, alternating positive and negative pressure therapy and pain medication, etc.
1.Vasodilator drugs can relieve vasospasm, promote the formation of collateral circulation and improve the blood supply to the affected limb.
2.Low molecular dextran and other expectorant drugs can reduce blood viscosity, improve microcirculation, and prevent the development and spread of thrombosis.
3.Sympathetic nerve closure can relieve pain in a short time, especially for those who have combined with severe vascular spasm.
4.Hyperbaric oxygen chamber therapy can increase the tissue oxygen supply to the limbs, reduce pain and have a certain effect on promoting the healing of ulcers.
5, analgesic treatment: pain is the more prominent symptom of patients with this disease, the affected limb ulcer, gangrene or secondary infection, the pain is more serious. General pain medication is often difficult to work, at this time can be appropriate to use morphine or dulcolax type painkillers. In order to prevent drug addiction, intra-femoral injection of procaine and lumbar sympathetic nerve closure can be used to reduce the amount of pain medication. If the effect of lumbar sympathetic nerve closure is obvious, lumbar sympathetic ganglionectomy should be performed in time.
6.Chinese medicine: such as Salvia tablets or injection and Mao Dongqing, etc.
Second, surgical treatment (see thrombo-occlusive vasculitis and aortitis)
Surgical modalities are mainly as follows
1, arterial endothelial stripping plus autologous vein piece repair priming surgery.
2, revascularization, bypass grafting.
3, percutaneous transluminal angioplasty (PTA)
4, lumbar sympathectomy.
5, venous arterialization.
6, subcutaneous transplantation of the greater omentum.
What is intermittent claudication?
Intermittent claudication is a type of motor pain, which is a typical symptom of chronic inadequate blood supply to the limb. Motor pain in the lower limb is mostly painful after walking a certain distance, and the pain disappears completely after resting for a few minutes; then the pain starts again after walking almost the same distance, and disappears completely after resting, so the medical term for pain of this nature is intermittent claudication. The more severe the ischemia of the lower limbs, the shorter the distance that can be walked. Intermittent claudication of the upper limb is also present, but not caused by walking. Intermittent claudication of the upper limb is mainly manifested in the feeling of sleepiness and weakness of the affected limb at work, especially when the upper limb is lifted up, and the upper limb has to hang down to relieve it.
What are the characteristics of intermittent claudication?
Intermittent claudication caused by arterial ischemia has the following characteristics.
1. The patient does not feel any pain before doing exercise or walking, but pain appears after walking a certain distance and has to stop exercising or walking. After a few minutes of rest, the pain can disappear completely.
2.The distance from the beginning of walking to the appearance of pain is basically the same each time.
3.The distance of walking uphill is shortened and, on the contrary, the distance of walking downhill is lengthened.
What diseases can cause intermittent claudication?
Diseases that can cause symptoms of intermittent claudication include lumbar spine diseases (mainly lumbar spinal stenosis diseases and joint diseases, especially geriatric joint diseases) and lower limb venous diseases (such as varicose veins of the lower limbs, post-thrombotic syndrome of the deep veins of the lower limbs, and malfunction of the valves of the deep veins of the lower limbs), in addition to insufficient blood supply to the arteries of the limbs.
How to distinguish ischemic intermittent claudication from intermittent claudication of venous diseases of the lower extremities?
Varicose veins of the lower extremities, post-thrombotic syndrome of the deep veins of the lower extremities, and poor valve function of the deep veins of the lower extremities are all venous diseases of the lower extremities, which can also cause intermittent claudication, and can be called venous intermittent claudication. The manifestations are also similar to lower extremity ischemic intermittent claudication, but not as pronounced as lower extremity ischemic diseases. The pain is mainly distension and heaviness, and the longer the walking distance, the heavier the distension and pain, just as people often say that the affected limb is as heavy as if filled with lead. Only after stopping and moving the legs for a while, such as repeated squatting and standing movements or raising the legs, can the symptoms be relieved or subside, and then the walking can continue.
How to distinguish intermittent claudication caused by lumbar spine diseases?
Some lumbar spine diseases, such as lumbar spinal stenosis, can also have similar intermittent claudication because this intermittent claudication is related to the compression of the spinal cord in the lumbar spine, so it is called neurological intermittent claudication. Intermittent claudication due to ischemia is called vascular intermittent claudication. There is a difference between the two types of intermittent claudication. Patients with intermittent claudication due to vascular disease prefer to walk downhill and walk a closer distance without pain each time. In contrast, patients with intermittent claudication caused by lumbar spinal stenosis prefer to walk uphill, and the distance of each painless walk is irregular, sometimes short and sometimes long, and is related to the patient’s posture when walking, such as bending over when walking, because the gap between the spine is increased, nerve compression can be reduced, and the walking distance can be extended.
What is the difference between pain in the lower extremities even when exercising with osteoarthrosis and intermittent claudication?
Patients with osteoarthrosis also experience pain during exercise, but the pain is the opposite of that caused by ischemia in the lower extremities. That is, the pain is heaviest at the beginning of the movement, and after moving for a while, the pain will be relieved, and then the pain may be reduced by continuing the movement, but it is always accompanied by pain. In contrast, ischemic intermittent claudication is characterized by pain that appears only after exercise or walking for a certain distance.
What is resting pain?
Severe vascular lesions with persistent pain even at rest are called resting pain. It generally indicates that the ischemia is significantly worse than in intermittent claudication.
Leriche syndrome.
In patients with atherosclerotic occlusion of the pelvic type, in addition to diminished or absent femoral artery pulsations, there is often intermittent claudication of the lower back, buttocks, thighs and calf muscles, and rarely trophic impairment of the extremities. This type is also known as Leriche’s syndrome.
What is Buerger’s syndrome all about?
In clinical practice, the initial diagnosis of most diseases is made by the physician by physical examination, and the results of the Buerger’s sign examination can provide useful information to the physician. This test was the first test used by Buerger the man, hence the name Buerger’s sign. Buerger’s sign is one of the tests used to determine if there is insufficient arterial blood supply to the limb.
How to do the Buerger’s sign test?
To examine the lower extremities, the patient should lie on his back, with both lower extremities straight and elevated, and the hip joint flexed at 45-90 degrees, and then observe the skin color of the patient’s feet after 3 minutes. When normal, the skin is light red or slightly white. When the arterial blood supply is insufficient, the skin color is pale. If the skin color does not change significantly, the patient can be asked to repeatedly flex and extend the ankle joint. A pale skin color on the foot after exercise is indicative of inadequate arterial blood supply. The degree of pallor is proportional to the degree of ischemia. In severe cases of inadequate blood supply, it may also cause discomfort or pain. The patient is then asked to sit up with both lower legs and feet naturally down, and the skin color of both feet is observed to change. Normally, within 10 seconds the white skin of the foot turns to normal. More than 10 seconds is indicative of an arterial supply deficit, which is a positive Buerger’s sign.
What is the dorsal foot vein filling time?
Normally, the dorsal foot veins are filled with blood even in a lying position, and in a sitting or standing position, the dorsal foot veins bulge significantly, i.e., they fill up. When the arterial supply to one side of the lower extremity is inadequate, the amount of blood in the dorsalis pedis vein decreases and the dorsalis pedis vein becomes significantly deflated compared to the normal side. The dorsalis pedis filling time test is also one of the tests to determine whether there is insufficient arterial supply to the lower extremity.
How do you test the dorsalis pedis filling time?
The test method is basically the same as the Buerger’s sign test, that is, let the patient lie on his back, make both lower limbs straight and elevated, hip flexion 45-90 degrees for more than 3 minutes, so that the veins of the lower limbs empty, then let the patient sit up, feet drop naturally, and observe the filling time of the dorsalis pedis bilaterally. The normal dorsal foot vein filling time is within 10 seconds, more than 10 seconds means the dorsal foot vein filling time is prolonged. The dorsalis pedis filling time can also be done in conjunction with Buerger’s sign.
What does a prolonged dorsalis pedis filling time mean for atherosclerotic occlusive disease?
The prolonged dorsal foot vein filling time indicates an arterial supply deficiency, the longer the filling time, the more severe the ischemia, and a filling time of 1 to 3 minutes indicates a severe supply deficiency. If the filling time exceeds 3 minutes, it indicates inadequate collateral circulation and is a precursor to gangrene.
What is the ankle/brachial ratio?
The ankle/brachial ratio is the ratio of the systolic pressure of the brachial artery to the arterial pressure of the ankle (dorsalis pedis or posterior tibial artery). A normal person should have an ankle/brachial ratio of ≥1.
What is the clinical significance of the ankle/brachial ratio?
When the ankle/brachial ratio is <1, it indicates a stenotic lesion in the artery of the affected limb. In general, intermittent claudication can occur when the ankle/brachial ratio is <0.8, and resting pain and extremity necrosis can occur when it is <0.5.