Abstract: Carotid stenosis is a serious threat to human survival and quality of life, and the traditional treatment method is carotid endarterectomy. In recent years, with the development of medical technology and the improvement of interventional devices, endovascular stenting has become the main treatment for carotid stenosis.
Overview
Cerebrovascular disease is a serious threat to human survival and quality of life. The incidence of cerebrovascular disease in the adult population is 150-200 per 100,000 people, of which ischemic cerebrovascular disease accounts for 75%-85%. Ischemic stroke is a common risk factor for disability, and the relationship between carotid stenosis and ischemic stroke is very close. The main causes are: reduced cerebral perfusion due to severe stenosis; cerebral infarction due to dislodgement of atheromatous plaques or microthrombi formed by plaque rupture. Studies have shown that about 1/3 of patients with ischemic strokes are related to carotid stenosis. The presence of carotid stenosis may cause chronic impairment of brain function (including attention, memory, emotion, thinking, intelligence, etc.) due to long-term ischemia, leading to a progressive decrease in social activity, even though no significant ischemic stroke has occurred. Therefore, carotid stenosis lesions should be treated actively.
Risk factors for carotid artery stenosis
The main pathological mechanism of carotid stenosis is atherosclerosis, which itself is a chronic process of organ aging, and atherosclerosis is also one of the main mechanisms of coronary artery disease (coronary atherosclerotic heart disease) and other brain and peripheral vascular pathologies. Therefore, carotid stenosis is actually the neck manifestation of systemic atherosclerosis, and the risk factors for carotid stenosis are also risk factors for coronary heart disease, cerebral thrombosis, and other important vascular diseases. The main ones are as follows.
1, hypercholesterolemia.
2, hypertension.
3, diabetes mellitus.
4, smoking.
5, overweight and obesity.
6, lifestyle: mental stress, high-calorie diet, lack of exercise, etc.
7, other: aging, more men than women.
The first three are usually called “three high” (high blood pressure, high blood pressure, high blood sugar), with the improvement of living standards, but the health concept is relatively backward, the occurrence of these risk factors is becoming younger and younger, this situation is the so-called “sub-health” state of the most important and This condition is one of the most important and major scenarios of the so-called “sub-health” state, and more and more young patients with related cardiovascular and cerebrovascular diseases are seen clinically.
Clinical manifestations of carotid artery stenosis
The danger of carotid stenosis is mainly twofold in terms of mechanism.
1. long-term chronic ischemia causing brain damage, resulting in dizziness, loss of vision, and decline in intellectual and social functions
2. ischemic stroke, divided into: (1) transient ischemic attack: substantial focal neurological deficits, symptoms of transient cerebral ischemia: dizziness, transient loss of consciousness, hemiplegia, and generally able to recover within 24 hours. About 70% of patients can be relieved within 10-15 minutes, and no symptoms remain after recovery. (2) Reversible ischemic attack: It refers to focal neurological deficit for more than 24 hours, which is completely relieved within a week. According to statistics, such patients account for 2.5%. (3) Cerebrovascular accident: It is a complete or permanent loss of brain function due to a local or permanent lack of blood supply to brain tissue.
Treatment of carotid artery stenosis.
General treatment includes risk factor control and antiplatelet therapy. Patients with stenosis of 70% or more should have aggressive therapeutic measures to relieve the stenosis to reduce the incidence of stroke and hemiplegic events.
(1) Carotid endarterectomy: superior to drug therapy in reducing the risk of stroke and was once considered the gold standard in the treatment of carotid stenosis.
(2) Carotid artery stenting: It is a minimally invasive method widely used in recent years for the treatment of carotid artery stenosis because it is less invasive, has faster recovery and is more effective. Compared with carotid endarterectomy, it has a wider range of indications. Patients with poor physical condition that cannot tolerate surgery, restenosis after carotid endarterectomy, carotid artery stenosis near the skull base, and intracranial artery stenosis can all choose stenting treatment.
Indications and contraindications for carotid artery stenting
The common clinical indications are: patients with symptomatic stenosis with >50% diameter stenosis or stenosis with ≥70% diameter stenosis, and this indication is gradually widening with the improvement of technology and materials and clinical research.
A common measure of stenosis rate is [1-(distal normal vessel diameter – narrowest diameter of stenotic segment)/proximal normal vessel diameter] × 100%.
Common causes of carotid artery stenosis suitable for stenting.
1, atherosclerotic carotid stenosis.
2, traumatic, medically induced carotid stenosis.
3, carotid artery entrapment aneurysm.
4, restenosis after endarterectomy treatment.
5, carotid artery thrombo-occlusive vasculitis.
6, poorly formed carotid intimal fibrous tissue.
7, tumor compression carotid artery stenosis.
Stenting of carotid stenosis is contraindicated in the presence of severe heart, brain, lung, kidney and other important organ failure, severe bleeding tendency or coagulation mechanism disorder due to various reasons, and a history of acute cerebral hemorrhage within 6 weeks.
General procedure of stent placement
1.Femoral artery puncture, with reference to previous angiographic findings, and delivery of the guiding catheter and micro-guide wire.
2.Pass the micro-guide wire through the stenosis and, if with a protective umbrella, hold the umbrella open at the distal end of the stenosis.
3.Deliver the balloon along the micro-guide wire to the stenosis, dilate the balloon, hold the arterial stenosis open, and withdraw the balloon when satisfied.
4. delivering the stent to the stenotic segment along the micro-guide wire, adjusting the position of the stent so that it completely covers the stenotic segment, and then releasing the stent.
5, re-imaging, if the stenosis is satisfactorily dilated, withdraw the guidewire and the procedure is completed. If unsatisfactory, the balloon can be dilated again.
Common complications of stent placement
1, cerebral hyperperfusion syndrome: due to the sudden expansion of the artery, the blood flow increases significantly, which can lead to cerebral hyperperfusion syndrome. The main clinical manifestations include headache, head swelling, nausea, vomiting, epilepsy, and impaired consciousness, and ipsilateral intracranial hemorrhage can occur in severe patients.
2. Bradycardia and hypotension: It is caused by the stimulation of pressure receptors in the carotid sinus after stent release, and the patient may show dizziness, etc.
3, ischemic stroke: the disintegration and dislodgement of atherosclerotic plaque and attached wall thrombus can lead to ischemic stroke, and the application of umbrella can reduce the chance of ischemic stroke.
4, vasospasm: stimulation of catheter, guidewire and contrast agent can lead to vasospasm.
5.Stent collapse, deformation and displacement.
6. Restenosis: There is a lack of information on long-term, large sample follow-up of restenosis after stent placement. The mean time to stenosis requiring retreatment with carotid stenting is 44 months. Stenting of the carotid artery resulted in >50% restenosis at 6 months (0%), 1 year (6%), 2 years (35%), and 3 years (56%).
Carotid artery stenting has few complications of surgical anesthesia and surgical injury, but the sclerotic plaque and thrombotic debris generated by vasodilatation during operation flowing down the bloodstream into the brain causing cerebral embolism is the main problem preventing its popularization. With the advancement of medical technology, brain protection devices for carotid stenosis interventions have emerged, and there are mainly two kinds of devices in common use: one is the distal filter for carotid stenosis (umbrella); the other is the distal obstruction balloon for carotid stenosis.
The distal umbrella, for example, is a precision device produced with high technology. Before the treatment of carotid stenosis in the stenosis, this device is sent to the distal part of the stenosis, where it is released to form a filter like an umbrella, and the small holes on the umbrella allow blood to pass, but the slightly larger carotid stenosis plaque and thrombus are blocked. After the carotid stenosis operation is completed, the umbrella can be closed like an umbrella to bring out the plaque and thrombus collected in it. This greatly reduces the complications of carotid stenosis stenting.