What to do if you suddenly have hemiplegia? This article will help you understand acute ischemic stroke

Author: Geng Jiewen, attending physician, Beijing Chaoyang Hospital, Capital Medical University

Reviewer: Wang Yang, Chief Physician, Beijing Chaoyang Hospital, Capital Medical University

1. What is a stroke?

We often hear the word "stroke". So, what exactly is a stroke? Stroke refers to local brain dysfunction caused by acute cerebrovascular disease. It ranks first among the causes of death among urban residents. It includes ischemic stroke (cerebral thrombosis, cerebral embolism) and hemorrhagic stroke (cerebral hemorrhage, subarachnoid hemorrhage).

2. What is acute ischemic stroke?

Acute ischemic stroke, commonly known as acute cerebral infarction, accounts for 70% of all stroke cases in my country. Acute generally refers to within 2 weeks after onset, while severe cases can be considered within 4 weeks after onset. Acute ischemic stroke can manifest as sudden weakness of one side of the limbs, speech disorders, facial numbness or crooked corners of the mouth, and impaired consciousness.

3. What causes acute cerebral infarction?

The most classic explanation for the etiology of cerebral infarction is the TOAST classification, which divides the causes of acute cerebral infarction into five types, including large artery atherosclerosis, cardiogenic embolism (mechanical valves, atrial fibrillation, atrial myxoma, sick sinus syndrome, etc.), small artery occlusion (lacunar infarction), other causes of stroke (non-atherosclerotic vascular disease, blood disease, etc.) and unexplained stroke.

4. How to quickly determine whether cerebral infarction is caused by acute occlusion of large blood vessels before hospitalization?

It is very important to judge cerebral infarction caused by acute large vessel occlusion. Timely and rapid opening of occluded large vessels plays a very important role in improving the prognosis of cerebral infarction. Patients, family members and pre-hospital emergency personnel can make judgments through G-FAST. The G-FAST score predicts acute anterior circulation large artery occlusion by adding the gaze item on the basis of the face-arm-speech-time (FAST) score. The sensitivity and specificity of the G-FAST score are not inferior to the NIHSS score, but it is simpler and easier to operate. The G-FAST scoring method includes four items: gaze, facial paralysis, speech disorder and upper limb weakness. Each positive item adds 1 point, and ≥3 points indicate that the patient has large vessel occlusion.

5. How are patients with large vessel occlusions transferred prehospital?

It is recommended that the patient be promptly transferred by ambulance to the nearest stroke center with thrombolysis and thrombectomy capabilities (within 30 minutes). When conditions permit, pre-hospital emergency care should be communicated with the hospital through the regional network to provide early warning, which will help with pre-hospital and in-hospital coordination.

Figure 1 Copyright image, no permission to reprint

6. What kind of imaging assessment should be performed on patients with acute ischemic stroke after admission to the hospital?

For patients with acute ischemic stroke, non-invasive examinations are recommended to determine whether there is large vessel occlusion and whether there are surgical indications, including: ① non-enhanced CT (NCCT) or magnetic resonance imaging (MRI): determine whether there is bleeding and calculate the ASPECTS score (to evaluate the core infarct area); ② cerebral blood flow perfusion: CT perfusion imaging/magnetic resonance cranial perfusion imaging (CTP/PWI), etc., to determine whether there is a core infarct area and ischemic penumbra area; ③ cerebrovascular examination: CT angiography/magnetic resonance angiography (CTA/MRA), which can most intuitively reflect whether there is large vessel occlusion. Which of the above examinations should be performed depends on the emergency habits of the stroke center. Sometimes, in order to ensure treatment time, direct thrombolysis or mechanical thrombectomy can be considered for patients with high NIHSS scores after CT examination.

Figure 2 Copyright image, no permission to reprint

7.What is intravenous thrombolysis?

Intravenous thrombolysis refers to the intravenous administration of thrombolytic drugs to restore or improve cerebral blood circulation. If the patient develops the disease within 4.5 hours and has no indication for thrombolysis, alteplase or tenecteplase thrombolysis can be actively given; urokinase can be used for thrombolysis at 4.5 to 6 hours. Whether thrombolytic therapy can bring benefits after onset for more than 6 hours is still controversial. The main complications of thrombolytic therapy include bleeding complications and vasogenic edema. Contraindications to thrombolytic therapy include intracranial hemorrhage, gastrointestinal bleeding, intracranial aneurysms, intracranial tumors, etc.

8.What is endovascular therapy?

It mainly refers to mechanical thrombectomy, in addition to arterial thrombolysis and stent angioplasty. Mechanical thrombectomy is a method of removing thrombi directly from blood vessels by suction or grasping. If the patient meets the conditions for thrombectomy within 6 hours, thrombectomy should be arranged for the patient as soon as possible; for patients within 6 to 24 hours, the doctor should consider the benefits and risks of thrombectomy in combination with the vascular condition, core infarction condition and penumbra condition. When the patient meets the conditions for both intravenous thrombolysis and mechanical thrombectomy, intravenous thrombolysis should be performed first, followed by bridging mechanical thrombectomy. If mechanical thrombectomy fails to open the occluded blood vessel, arterial thrombolysis is one of the remedies. The main risks of mechanical thrombectomy include bleeding, vascular damage, ineffective recanalization, etc.

The effectiveness of mechanical thrombectomy is mainly evaluated by mTICI grading. The general goal of thrombectomy is to achieve mTICI 2b/c grade recanalization of blood flow, that is, "partial perfusion of forward blood flow, greater than 50% of the downstream ischemic area (for example, two main branches of the middle cerebral artery are recanalized)" or "complete restoration of perfusion of the distal ischemic area, and no visible occlusion of the distal branches."

Figure 3 Copyright image, no permission to reprint

9. What are the drug treatments and postoperative treatment options for patients with acute ischemic stroke?

Including antiplatelet/anticoagulation, prevention and treatment of edema, neuroprotection, prevention of bedridden complications, targeted rehabilitation, etc.

10. When is the best time to start anticoagulation therapy for atrial fibrillation?

Patients with atrial fibrillation should choose the appropriate time for anticoagulation after surgery to prevent further detachment of thrombus. However, in order to prevent early hemorrhagic transformation of infarction, the 1-3-6-12 strategy is generally adopted, that is, anticoagulation should be started one day after the onset of transient ischemic stroke, three days after the onset of mild stroke (NIHSS ≤ 8), six days after the onset of moderate stroke (NIHSS 8-15), and 12 days after the onset of severe stroke (NIHSS ≥ 16).

Through the above introduction, everyone must have a certain understanding of acute ischemic stroke. The general principle is: after the onset of the disease, transfer to the nearest stroke center capable of thrombolysis and thrombectomy as soon as possible, and use symptom scoring and imaging examinations to promptly determine whether there is large vessel occlusion. Perform intravenous thrombolysis or intravascular treatment on patients who meet the indications as soon as possible within the time window. Safe and effective medication and rehabilitation treatment are performed after surgery. Through these practices, there is hope to greatly reduce the risk of disability and death caused by acute ischemic stroke.