I. Overview
Stroke, also known as cerebral stroke, is a disease state caused by the rupture or blockage of a blood vessel in the brain. It is a disease with high morbidity, mortality, and disability, and is one of the “three major killers” (cerebrovascular disease, cardiovascular disease, and tumors) of humans. About 3/4 of stroke survivors have varying degrees of disability, which has a huge impact and burden on the patient, family and society.
Stroke can be divided into ischemic, which refers to cerebral ischemia due to narrowing or occlusion of blood vessels, and hemorrhagic, which refers to cerebral hemorrhage due to rupture of blood vessels. Studies have shown that about 1/3 of patients with ischemic strokes are associated with carotid stenosis, which can cause chronic impairment of cognitive function (including attention, memory, emotion, thinking, and intelligence) due to long-term ischemia without significant ischemic stroke, resulting in progressive reduction of social activity. With the improvement of disease awareness and technology, early preventive treatment of these diseases before stroke occurs has become possible, with research and treatment of carotid artery stenosis at the forefront.
Currently, the main treatments for carotid stenosis include medication, carotid endarterectomy, and interventional stenting for carotid stenosis. Compared to surgical treatment, interventional stenting has the following advantages.
1, less invasive and relatively safer;
2. It can treat a wide range of stenosis sites, and can even be used to treat intracranial artery stenosis. At the same time, as a relatively new technology, the cost of interventional stenting is more expensive than surgery, and the long-term efficacy has yet to be more fully evaluated.
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 heart disease (coronary atherosclerotic heart disease) and other cerebral and peripheral vascular pathologies. Therefore, carotid stenosis is actually the neck manifestation of systemic atherosclerosis, and risk factors for carotid stenosis are also risk factors for coronary artery disease, cerebral thrombosis, and other important vascular diseases. Certain lifestyles and pathological states can accelerate the occurrence and development of atherosclerosis, which we call high-risk factors, and the common 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 situation is one of the most important and major situations of the so-called “subhealth” state, and more and more young patients with related cardiovascular and cerebrovascular diseases are seen clinically.
Clinical manifestations of carotid artery stenosis
The harm of carotid artery stenosis is mainly twofold in terms of mechanism.
1.Long-term chronic ischemia causes brain damage, resulting in dizziness, vision loss, intellectual and social function decline, etc;
2. Atherosclerotic plaque or attached thrombus can be formed at the stenosis site, and the plaque or thrombus can be dislodged and block the downstream cerebral vessels, leading to recoverable transient ischemic attack (TIA) in mild cases, which can be manifested as sudden dizziness, temporary blackness of one eye, numbness and weakness of arms and legs, slurred speech, weakness of one limb, unstable holding and crooked mouth, etc., often recovering within 24 hours; in severe cases, leading to acute cerebral infarction, causing permanent hemiplegia, hemianesthesia, hemianopsia and language dysfunction, etc.
Indications and contraindications for carotid artery stenting
The common clinical indications are: symptomatic stenosis with ≥70% diameter stenosis, but with the improvement of technology and materials and clinical research, this indication has been gradually broadened.
The common measurement of stenosis rate: (distal normal vessel diameter – narrowest diameter of stenotic segment) / proximal normal vessel diameter] × 100%.
V. Common causes of carotid artery stenosis that are suitable for stenting or exist.
1.Arteriosclerotic carotid artery stenosis;
2. Traumatic or medically induced carotid stenosis;
3.Carotid artery entrapment aneurysm;
4, restenosis after endarterectomy treatment;
5.Carotid artery thrombo-occlusive vasculitis;
6.Carotid artery intima-media fibrous tissue malformation;
7, tumor compression carotid artery stenosis.
Stenting of carotid artery stenosis is not recommended in the presence of severe heart, brain, lung, kidney and other important organ failure, severe bleeding tendency or coagulation mechanism disorder caused by various reasons, and a history of acute cerebral infarction or bleeding within 6 weeks.
VI. General procedure of stent placement
1.Femoral artery is punctured, and the guiding catheter and micro-guide wire are delivered with reference to the previous imaging results;
2.Pass the micro-guide wire through the stenosis, or open the umbrella at the distal end of the stenosis if it has a protective umbrella;
3.Deliver the balloon to the stenosis along the micro-guide wire, dilate the balloon and open the artery stenosis, and withdraw the balloon when satisfied;
4. Send the stent to the stenosis with the micro-guide wire, adjust the position of the stent so that it completely covers the stenosis, and then release the stent;
5, re-imaging, if the stenosis expansion is satisfactory, withdraw the guidewire, the operation is completed. If the stenosis is not satisfactorily dilated, the balloon can be dilated again.
The above procedure can be briefly described as: placement of micro-guide wire D>propagation of umbrella D>pre-dilation D>placement of stent D>post-dilation D>finish.
Knowledge of the above equipment: micro guidewire; umbrella; balloon; stent;
VII. 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.