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Table of Contents
GUIDELINE AND CONSENSUS
Year : 2018  |  Volume : 3  |  Issue : 2  |  Page : 71-80

ST-Segment elevation acute myocardial infarction prehospital thrombolytic therapy: Chinese expert consensus


Department of Cardiology, Peking University First Hospital, Beijing, China

Date of Web Publication16-Jul-2018

Correspondence Address:
Yong Huo
Department of Cardiology, Peking University First Hospital, Beijing
China
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/cp.cp_12_18

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  Abstract 


Acute myocardial infarction (AMI) still seriously threatens the health of the people in our country. The situation is even more severe in the vast urban and rural areas in China. Timely treatment of AMI patients to reduce mortality and protect heart function is very important. Prehospital thrombolysis treatment has great significance in urban and rural areas outside the big cities. To this end, the Chinese Medical Doctor Association's chest pain professional committee and the Chinese Medical Rescue Association's Cardiovascular Emergency Sub-Commission organized relevant experts to formulate this consensus, aiming to help prehospital medical emergency personnel select the best treatment strategies for patients with AMI. However, the final decision on a specific patient should be made by the prehospital emergency personnel together with the patients and their family members.

Keywords: Consensus, prehospital, ST-segment elevation myocardial infarction, thrombolytic therapy


How to cite this article:
Yan H, Xiang D, Liu H, Chen H, Chen J, Chen Y, Chen Y, Chu Y, Fang W, Fu X, Lie C, Mao W, Pang S, Shi R, Su X, Wang Y, Wang G, Wang W, Xu M, Yang L, Yu H, Yuan Z, Zheng Z, Huo Y. ST-Segment elevation acute myocardial infarction prehospital thrombolytic therapy: Chinese expert consensus. Cardiol Plus 2018;3:71-80

How to cite this URL:
Yan H, Xiang D, Liu H, Chen H, Chen J, Chen Y, Chen Y, Chu Y, Fang W, Fu X, Lie C, Mao W, Pang S, Shi R, Su X, Wang Y, Wang G, Wang W, Xu M, Yang L, Yu H, Yuan Z, Zheng Z, Huo Y. ST-Segment elevation acute myocardial infarction prehospital thrombolytic therapy: Chinese expert consensus. Cardiol Plus [serial online] 2018 [cited 2019 Aug 20];3:71-80. Available from: http://www.cardiologyplus.org/text.asp?2018/3/2/71/236817




  Introduction Top


Acute myocardial infarction (AMI) refers to persistent chest discomfort or other symptoms suggestive of myocardial ischemia. There is also evidence of myocardial damage and necrosis (the increase in cardiac troponin levels exceeds normal limits at least once). In patients with AMI, there is ST elevation in two or more contiguous leads in the electrocardiogram, which is called ST-segment elevation myocardial infarction (STEMI). Without ST elevation, it is called non-STEMI (NSTEMI).[1],[2],[3]

In Europe and North America, with the promotion of primary percutaneous coronary intervention (PPCI), modern antithrombotic therapy, and secondary prevention, STEMI mortality has declined but still remains very high. STEMI patients without PPCI have an in-hospital mortality rate of 4%–12% and an annual mortality rate of approximately 10%.[2],[3] Unlike Europe and North America, the incidence of AMI in urban and rural residents in China has been on the rise, and the annual STEMI mortality rate could be higher [Figure 1].[4] The important issue we are currently facing is the low rate of timely reperfusion therapy in STEMI patients.[4],[5] Prehospital thrombolysis is an important part of timely reperfusion therapy.[1],[2],[3] However, at present, there is a lack of relevant training for prehospital emergency personnel in the country, and there is a lack of understanding of early diagnosis, risk stratification, and thrombolytic therapy for acute STEMI patients. There is an urgent need to formulate a scientific expert consensus to guide prehospital emergency personnel.
Figure 1: Mortality trends of acute myocardial infarction in urban and rural areas from 2002 to 2015

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Reperfusion therapy strategies for STEMI patients include drug thrombolytic therapy, PPCI, and emergency surgical coronary artery bypass grafting. In the case of failure to perform PPCI in a timely manner, drug thrombolytic therapy is an important reperfusion therapy strategy. For every 1000 patients treated within 6 h of onset, 30 early deaths can be prevented. Prehospital thrombolytic therapy is superior to thrombolysis after admission, and thrombolytic therapy can be initiated in ambulances when conditions permit. Compared with in-hospital thrombolytic therapy, the early mortality rate of prehospital thrombolytic therapy was reduced by 17%, especially in patients whose onset time was <120 min.[3],[6],[7],[8],[9],[10],[11],[12],[13],[14],[15]


  Early Diagnosis and Early Treatment of St-Segment Elevation Myocardial Infarction Top


STEMI is first diagnosed on the basis of ischemic symptoms (continuous chest pain) and a 12-lead electrocardiography (ECG) [preferably 18 leads; [Table 1].[1],[2],[3] A history of coronary heart disease and pain radiation to the neck, jaw, and left arm are important clues to myocardial infarction. Some patients may present with shortness of breath, nausea/vomiting, fatigue, and palpitations/fainting. Reduced chest pain after taking nitroglycerin cannot be used as a diagnostic basis. When symptoms are relieved after taking nitroglycerin, a 12-lead ECG must be performed again. If the ST segment is completely down and the symptoms are completely relieved, it indicates coronary artery spasm (with or without myocardial infarction).[1],[2],[3]
Table 1: Early diagnosis and treatment of ST-elevation myocardial infarction

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All patients with suspected STEMI should have ECG monitoring as soon as possible to detect life-threatening arrhythmias and rapid electric cardioversion when necessary. Care providers of patients with suspected STEMI must obtain and read a 12-lead ECG as soon as possible during the first medical contact (FMC) to speed up the early diagnosis and management of STEMI. Some special types of patients may affect the judgment of the ST segment of the electrocardiogram [Table 2]. If the first clinician has difficulties with a diagnosis, they should be transmitted promptly to a cardiovascular specialist for immediate diagnosis.[5],[16]
Table 2: Several situations affecting the interpretation of electrocardiograph

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For patients with confirmed STEMI, reperfusion therapy should be started as soon as possible. When ECG performance is uncertain or there is no evidence to support a suspected diagnosis of myocardial infarction, ECG examination should be repeated to compare as much as possible with previous ECG records. If the prehospital electrocardiogram cannot be interpreted on site, transmit the ECGs to hospital for interpretation.

The most important distinction in diagnosis is to exclude simultaneous aortic dissection. For all patients with ST-segment elevation acute chest pain, we must carefully ask whether there is tear-like chest and back pain at the time of onset, and we prefer to delay thrombolysis and antithrombotic therapy when there is high suspicion. Before treatment, a patient should first be sent to a hospital to obtain a confirmed diagnosis.[5],[16],[17]

Patients who still have chest pain and hypoxemia should be treated as soon as possible [Table 3]. Intravenous (IV) opioids (such as morphine) are currently the most commonly used analgesic methods. However, morphine can cause slow absorption, delayed onset of action, and reduced efficacy of oral antiplatelet agents (clopidogrel and ticagrelor).[5]
Table 3: Relieves hypoxemia and symptoms

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STEMI due to obstruction of the left main artery, opening or proximal occlusion of the left anterior descending artery, or obstruction of the proximal right coronary artery are more dangerous

Recognizing ECG performance can help with risk stratification. The typical ECG of the left main lesion shows ST-segment elevation in the lead aVR, and the ST segment depression in leads I, II, and V4–V6. If there is ST elevation in lead V1, the aVR lead elevation should be greater than V1 lead. ECG manifestations of the left anterior descending in open or proximal lesions show an extensive elevation of the ST segment in the precordial leads with ST elevation in leads I and aVL and a downward shift in the ST segment in the inferior leads. The ECG of proximal right coronary artery disease shows ST elevation in leads II, III, and aVF, ST elevation in lead III is greater than in lead II, and it is accompanied by ST elevation in leads I and/or aVL. ST elevation in the right ventricular leads.[3],[4],[5]


  Early Reperfusion Therapy Options Top


Prehospital ambulances should be based on the following principles when selecting reperfusion strategies for STEMI patients [Figure 2]. If there is a feasible PPCI hospital nearby, can transfer the patient to the hospital within 120 min and complete the PPCI. Otherwise, the following important factors should be quickly assessed: (1) The time of onset of symptoms; (2) the risk of STEMI-related complications; (3) the risk of bleeding from drug thrombolysis; (4) shock or severe heart failure; and (5) how long it takes to transfer to a viable PPCI hospital. For early patients, even if the transit time is very short, the immediate thrombolytic strategy is better than the delayed emergency PPCI. The high-risk groups including the elderly have the greatest absolute benefit of thrombolysis within 120 min after onset. Delayed PPCI over 120 min after onset of symptoms compared with immediate thrombolysis had no advantage in survival.[6],[7],[8] In the absence of contraindications, patients who are expected to complete PPCI >120 min from FMC should be given thrombolytic therapy within 30 min. The later the patient comes to the hospital (especially after more than 3 h of onset); the more consideration should be given to transporting them to a hospital for PPCI (rather than thrombolytic therapy). As the onset time increases, the clinical benefit of thrombolysis will decrease. However, patients with STEMI who have symptoms more than 12 h after onset of symptoms and have a large range of ischemia or hemodynamically unstable STEMI can be treated with thrombolysis if they are not eligible for PPCI. When thrombolytic contraindications exist, it is important to balance the lifesaving effects of thrombolysis and potential fatal adverse reactions. Other alternative treatments are considered at this time such as delaying PPCI.[3],[4],[5],[6],[7],[8]
Figure 2: Selection of reperfusion therapy for patients through prehospital emergency care systems or at nonpercutaneous coronary intervention hospitals

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  Prehospital Thrombolytic Therapy Top


Prehospital thrombolytic therapy (especially in ambulances) is an effective means to improve the early reperfusion treatment rate in STEMI patients in China. It is necessary to have the basic conditions for prehospital thrombolytic therapy and to recognize indications and contraindications, deal with the complications of thrombolytic therapy, and establish an effective treatment network with related hospitals.[9]

Basic conditions for prehospital thrombolysis treatment

Due to the unstable condition of STEMI patients, severe reperfusion injury and reperfusion arrhythmias may occur during thrombolysis. Improper handling may endanger the life of the patient. Therefore, the prehospital thrombolytic therapy must have the following basic conditions:

  1. Basic ambulance conditions: ECG recording equipment (electrocardiograph or ECG monitoring equipment above 12 leads), monitors (ECG, blood pressure, SaO2, etc.), defibrillators, on-board oxygen supply, various types of rescue drugs, and thrombolytic drugs
  2. Personnel Conditions: The ambulance should be equipped with a physician and a nurse who have undergone cardiopulmonary resuscitation training. At least one of them should be skilled in advanced, high-level cardiopulmonary resuscitation techniques
  3. Prehospital thrombolysis work documents: Thrombolysis screening table, prehospital thrombolysis informed consent, and thrombolysis operation procedures
  4. Remote support conditions: Regional collaborative information sharing platform, remote support team with participation of cardiologists and emergency physicians in decision-making, and one-click telephone activation to ensure confirmation before thrombolytic treatment, remote guidance and treatment in the event of an emergency, and guidelines and contacts for transit destinations, etc.


Indications and contraindications for prehospital thrombolytic therapy

Performing prehospital thrombolysis treatment should have all the following four conditions: (1) acute chest pain lasts for more than 30 min but not more than 12 h; (2) An ECG with ST elevation in two or more contiguous leads ≥0.1 mV in the limb leads, ≥0.2 mV in precordial leads or a new complete left (or right) bundle branch block; (3) age <75 years; and (4) cannot complete PPCI within 120 min.

The decision to preform thrombolysis should be based on a comprehensive analysis of the expected risk/benefit ratio, onset-to-visit time, clinical and hemodynamic characteristics at presentation, comorbidity, bleeding risk, contraindications, and anticipated PCI delays.

The most common side effect of thrombolytic therapy is bleeding. Therefore, high-risk patients must be excluded before thrombolysis [Table 4].[3],[4],[5] Given that prehospital thrombolysis treatment is performed in a relatively uncomplicated medical environment in ambulances, the treatment conditions and capabilities for severe bleeding are limited, but contraindications should be strictly controlled. In addition to patients with absolute contraindications, patients with relative contraindications should also be strictly controlled. Thrombolysis should not be performed before hospitalization for any patient with absolute or relative contraindications.
Table 4: Contraindications for thrombolytic therapy

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Related documents for prehospital thrombolysis

The prehospital thrombolytic therapy screening table [Table 5][4],[5] can facilitate rapid prehospital emergency personnel screening for patients undergoing thrombolytic therapy. All patients must be screened by the prehospital emergency physician before thrombolytic therapy. The screening table consists of two parts: the first part is the screening of indications. If all requirements are met, i.e., the answer to all questions is “yes,” then thrombolytic therapy may be considered. If any of the answers is “no”, screening can be terminated, and the patient cannot be treated with thrombolysis. The second part is contraindication screening, requiring all questions to be answered “no” to safely perform thrombolytic therapy. If any of the questions answered “yes,” screening can be terminated screening and the patient cannot undergo thrombolytic therapy.
Table 5: Thrombolytic therapy screening for ST-elevation myocardial infarction

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Informed consent should be given before thrombolytic therapy because treatment may cause adverse reactions such as hemorrhage and reperfusion arrhythmia and may also cause death or disability in severe cases where thrombolysis fails. Even with the third generation of specific thrombolytic drugs, the success rate is only about 80%. Of which only about 65% of patients achieve Grade III thrombolysis in myocardial infarction (TIMI). There is still about a 35% failure rate for thrombolysis with inadequate reperfusion that requires rescue PCI.[3],[4],[5] Therefore, in accordance with current medical regulations in China, informed consent should be obtained before thrombolysis with signed informed consent forms.

The informed consent process should be as concise as possible to explain the patient's condition, diagnosis, possible consequences (mortality of nonreperfusion therapy), current possible choices of treatment, and benefits of thrombolytic therapy (to reduce mortality and heart failure rate). Bleeding risk is the focus of informed consent and should highlight the possibility of severe bleeding, especially intracranial hemorrhage (0.9%–1%). Although patients have been strictly screened for risk of bleeding, there is still a small risk of severe, life-threatening bleeding in some patients. However, it must be emphasized that, for patients with STEMI, thrombolytic therapy is a “significant benefit, low-risk” life-saving rescue measure. It must be “fast” and cannot be delayed because of repeated consultations with others. In addition, both doctors and patients must sign the informed consent form and note the time, which must be accurate to the minute. It is suggested that the thrombolytic screening table and thrombolysis informed consent form should be prepared in the ambulance for prehospital thrombolytic therapy. After the first ECG diagnosis, the thrombolytic screening should be performed. After the screening, the physician should sign the informed consent form including the time and then talk to family or patient. Finally, the family or patient should sign the consent form including the time.

Thrombolytic therapy and anticoagulant/antiplatelet therapy

The main thrombolytic drugs currently in clinical use include nonspecific plasminogen activator and specific plasminogen activator. The former includes urokinase and streptokinase.[3],[5] Because nonspecific plasminogen activator thrombolytic drugs have low thrombolytic recanalization rates and are inconvenient to use and are not particularly suitable for prehospital thrombolytic therapy, this consensus does not recommend this treatment. Specific plasminogen activators are suitable for prehospital thrombolytic therapy [Table 6].[18],[19]
Table 6: Usage and dosage of thrombolytic/anticoagulant therapy

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The mechanism of action of fibrin-specific plasminogen activator is to degrade fibrin in thrombus into fibrin fragments to dissolve thrombus but not to degrade fibrinogen in circulation. Due to the high activity of the coagulation system that promotes thrombosis in the early stages of AMI, the coagulation and fibrinolysis system is in a dynamic equilibrium, and new thrombosis is still occurring at the same time or after the dissolution of thrombolytic drugs. Therefore, anticoagulation and antiplatelet therapy must be combined during and after thrombolytic therapy to inhibit new thrombosis and prevent reocclusion.

At present, anticoagulants recommended for AMI include unfractionated heparin, enoxaparin, fondaparinux, and bivalirudin.[3],[4],[5],[20] This consensus does not recommend the routine use of fondaparinux or bivalirudin for anticoagulant therapy in patients undergoing prehospital thrombolysis. Unfractionated heparin or enoxaparin should be used as an adjuvant anticoagulant for prehospital thrombolytic therapy [Table 6].

Dual antiplatelet therapy is the basic treatment for all STEMI patients. All patients with STEMI who have no contraindications should start dual antiplatelet therapy as soon as possible after diagnosis [Table 6]. For patients who have not had long-term regular aspirin use before the onset of illness, 300 mg of aspirin should be chewed immediately; for patients taking long-term aspirin, an additional 150 mg should be added. All thrombolytic patients should be given a 300 mg loading dose of clopidogrel (maintenance dose 75 mg once daily)[3],[4],[5] or 180 mg ticagrelor (maintenance dose 90 mg twice daily).[21]

Evaluation of thrombolysis

The purpose of thrombolytic therapy is to open infarct-related blood vessels as soon as possible by dissolving thromboembolism, restore myocardial perfusion, rescue myocardial necrosis due to ischemia, reduce infarct size, reduce early mortality, and preserve patients' cardiac function. Clinical assessment and coronary angiography are two common methods for assessing the efficacy of thrombolysis.

Clinical evaluation of the success of thrombolytic therapy is marked by 60–90 min after thrombolytic therapy: (1) elevated ST segment fell ≥50%; (2) chest pain relief or disappearance; (3) reperfusion arrhythmias such as accelerated ventricular spontaneous rhythm, ventricular tachycardia, even ventricular fibrillation, atrioventricular block, sudden improvement or disappearance of bundle branch block, or transient sinus bradycardia, sinus atrial block in patients with inferior myocardial infarction with or without hypotension. The most valuable of these is accelerating ventricular spontaneous rhythm, but its sensitivity and specificity are not high; (4) the peak of markers of myocardial necrosis is advanced, for example, the peak of cardiac troponin is advanced to within 12 h after the onset. Creatine kinase isoenzyme peak advances to within 14 h.

The above indicators need to be judged retrospectively and cannot be used for early prognosis. The typical performance of successful thrombolytic therapy is an elevated ST segment drop of ≥50%, combined with marked relief of chest pain and/or reperfusion arrhythmias.[3],[4],[5],[22]

Coronary angiography is the gold standard for judging the success of thrombolysis. Failure is defined as persistent occlusion of infarct-related vessels at 90 min after thrombolysis (TIMI flow Grade 0 to I), and success criteria are TIMI flow Grade II or III, with TIMI flow Grade III being complete revascularization [Table 7].[3],[4],[5]
Table 7: Thrombolysis in myocardial infarction flow classification

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Treatment and transshipment target hospital selection after prehospital thrombolysis

Early thrombolytic therapy can improve the STEMI reperfusion rate, but thrombolysis is not the end of treatment, and early coronary angiography after thrombolysis is of utmost importance. First, even if specific plasminogen activators are used early in the disease, the average thrombolytic success rate is only about 80%. Among them, only about 65% of TIMI blood flow Grade III is truly achieved. About 35% of patients still fail to recover effective myocardial perfusion.[3],[4],[5] Such patients should receive rescue PCI as soon as possible to save the surviving myocardium. Second, for patients with successful thrombolysis, very early postoperative coronary angiography (<2 h) did not increase the risk of death or recurrent myocardial infarction and severe bleeding during hospitalization for 30 days.[4],[5] Routine early coronary angiography after thrombolysis and PCI, if necessary, can reduce recurrent MI and recurrent ischemia without increasing the risk of adverse events (stroke or severe bleeding). For this reason, ambulances carrying out prehospital thrombolytic therapy should transfer patients to hospitals that are able to implement PPCI as soon as possible after the start of thrombolytic therapy (PPCI hospitals that have established a chest pain center are preferred). If thrombolytic therapy fails or evidence of reocclusion of the blood vessel or recurrent myocardial infarction is evidenced by a re-elevation in the ST segment, coronary angiography and rescue PCI should be performed immediately. Even if thrombolytic therapy may be successful, coronary angiography is routinely performed within 24 h without contraindication [Figure 3]. Only when the patient's vital signs after thrombolysis are extremely unstable and urgent cardiopulmonary resuscitation (CPR) is needed and it is not expected to be safely transferred to the PPCI hospital, it is recommended that the patient is transported to the nearest non-PCI hospital for emergency CPR.
Figure 3: Flow chart of ST-segment elevation myocardial infarction prehospital care and thrombolytic therapy under regional cooperative care system

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  Prehospital Thrombolysis Therapy Complications' Identification and Treatment Top


The major complications of prehospital thrombolytic therapy are bleeding and reperfusion arrhythmias, and prehospital thrombolytic treatment personnel must be familiar with the basic treatment principles.

Bleeding complications and prehospital treatment

The main bleeding risk of thrombolytic therapy is intracranial hemorrhage (0.9%–1.0%) and gastrointestinal bleeding. Older age, lower weight, women, previous history of cerebrovascular disease, and uncontrolled high blood pressure are the major risk factors for intracranial hemorrhage. Tips of the main manifestations of early intracranial hemorrhage are changes in consciousness, confusion, drowsiness, and coma, with or without facial or paralysis. Once intracranial hemorrhage is suspected, thrombolytic therapy and antithrombotic (anticoagulant and antiplatelet) therapy should be stopped immediately, and the patient should be sent to a hospital for urgent head computed tomography or magnetic resonance imaging to determine hematocrit, hemoglobin, prothrombin, and activation, activated partial thromboplastin time, platelet count, fibrinogen, D-dimer, and blood tests and crossmatching. Emergency treatment measures in ambulances include lowering intracranial pressure (appropriately controlling blood pressure, raising the head of the bed 30°, IV mannitol, tracheal intubation, and assisted ventilation, etc.). The main goal is to keep the patient's vital signs basically stable. It is sent to hospitals with processing capabilities for follow-up treatment. For the patients with major bleeding in the digestive tract (usually the upper digestive tract), the basic principles of treatment are the same as above, and attention should be paid to prevent aspiration during hematemesis. If possible, nasogastric tube drainage should be performed as soon as possible, and nasogastric tube or oral administration containing 0.1% of norepinephrine ice salt water stops bleeding.

Reperfusion arrhythmia

Reperfusion arrhythmia refers to autolysis after coronary artery thrombosis, reperfusion by drug thrombolysis, or PPCI, recanalization of obstructed coronary arteries, remission of coronary arteries, etc. The reperfusion arrhythmia is a main manifestation of myocardial reperfusion injury. The incidence of reperfusion arrhythmia in all patients with thrombolysis was above 64%. Almost all patients with thrombolytic therapy develop reperfusion arrhythmias that occur at the instant of reperfusion or within 2–3 h. Reperfusion arrhythmias manifest themselves in a variety of forms including accelerated ventricular arrhythmia, ventricular premature beats, ventricular tachycardia, ventricular fibrillation, and other tachyarrhythmias, as well as bradycardia, high degree of atrioventricular block, and other types of slow type arrhythmia. Among them, patients with anterior myocardial infarction were more frequently seen with rapid arrhythmia, whereas those with inferior myocardial infarction were mainly slow arrhythmia.

The types of reperfusion arrhythmias are complex and varied. Some of these patients require urgent treatment for dangerous, life-threatening arrhythmias. The timely detection and management of reperfusion arrhythmia is one of the most important tasks in the process of prehospital thrombolytic therapy. It is suggested that prehospital thrombolytic treatment personnel do the following work: (1) Check and prepare rescue equipment such as defibrillation device and endotracheal intubation, and various types of anti-arrhythmic drugs, including atropine, lidocaine, and dopamine. (2) Strengthen the whole process of monitoring after thrombolytic therapy. ECG, blood pressure, and SaO2 monitoring should be established before thrombolysis. During the thrombolytic process and during transit, the information of the monitor should be kept within the visual field of the physician and/or nurse so that reperfusion arrhythmias can be detected in time and/or hemodynamic disturbances. If conditions are available, modern remote real-time monitoring equipment can be used. The hospital staff in the chest pain center are involved in monitoring and remote first-aid guidance during transit after thrombolysis. (3) Emergency treatment: In the event of reperfusion arrhythmias, appropriate treatment should be taken according to the type of arrhythmia. For example, bradycardia arrhythmia can be preceded by a forced cough and atropine 0.5–1 mg intravenously as soon as possible. If frequent ventricular or ventricular premature beats, accelerated ventricular spontaneous rhythm, or ventricular tachycardia occur, IV injection of lidocaine 75–100 mg may be given. Continuous IV infusion of 1–4 mg/min may be effective. If lidocaine is ineffective, use amiodarone 150 mg diluted intravenously and if necessary, maintain an IV infusion of 1–3 mg/min. If torsades de pointes ventricular tachycardia or ventricular fibrillation, or monomorphic ventricular tachycardia with hemodynamic disturbances, electrical cardioversion is performed as soon as possible. Patients with recurrent episodes of electrical storms should be given IV β-blockers as soon as possible. If there is a drop in blood pressure, vasoactive drugs such as dopamine should be used as soon as possible to raise the blood pressure to a safe range. Patients undergoing cardiac arrest should undergo standard CPR in a timely manner. (4) Arrhythmia and hemodynamic disorders caused by reperfusion injury are usually transient. If they can be detected and treated correctly, the heart rhythm and hemodynamic status will quickly return to normal. If the episode of malignant arrhythmia occurs repeatedly or is ineffective, contact a heart specialist at a center for chest pain as soon as possible.


  ST-Segment Elevation Myocardial Infarction Treatment System Construction and Prehospital Thrombolytic Therapy Top


Because STEMI patients often have acute chest pain as the first symptom, most patients are first diagnosed in primary hospitals that do not have PPCI capability. Even patients admitted through ambulances are often sent to hospitals that are nearby but have no treatment capacity. Two referrals are required before reaching the PPCI hospital. Therefore, it is very important to establish an early rapid treatment system for STEMI. Since our country established the first chest pain center with the regional coordinated treatment system as its core in 2011, the chest pain center has become the main carrier of the STEMI treatment system in China.[23] Under the promotion of the chest pain center certification and the “National Institute for the Prevention and Treatment of Chest Pain Centers” (trial)[24] issued by the National Health and Family Planning Commission, China's STEMI treatment system is gradually being formed.

The core concept of the ST-segment elevation myocardial infarction treatment system

The core concept of the construction of the chest pain center in China is to integrate the regional medical resources and establish an emergency treatment to deliver the patients with acute chest pain to the treatment facilities in the shortest time to receive the best treatment. For STEMI patients, it is to achieve reperfusion therapy in the shortest possible time.

Key links and working mechanisms for the construction of regional cooperative medical treatment system

The key links in the establishment of a regional collaborative rescue system include PPCI hospitals, primary hospitals that do not have PPCI capabilities, and prehospital emergency systems. Based on the actual conditions of our country, hospitals with PPCI capabilities should take the initiative to undertake the main tasks of the STEMI Regional Cooperative Rescue System, by forming a PPCI team that responds at any time, by establishing the first treatment mechanisms, and by establishing a hospital green channel for STEMI treatment. The door-to-balloon time of STEMI should be shorter than 90 min. On this basis, an information platform (Weixin Group or other emergency information platform) shared with prehospital emergency and non-PPCI hospitals, and a one-button telephone activation has been established. When an acute chest pain patient dials an emergency phone, the ambulance arrives at the scene and completes first ECG within 10 min. The first ECG is transmitted to the chest pain center information sharing platform, and a cardiologist at the PPCI hospital is notified by one-key activation on the telephone. For a well-diagnosed STEMI, if it can be sent to the nearest PPCI hospital and complete the PPCI (including transshipment and door-ball time) within 120 min, the bypass the emergency room and CCU direct access to the catheterization room to minimize treatment time and as soon as possible to open the occluded coronary artery. If the above transshipment and PPCI cannot be completed within 120 min, thrombolysis should be initiated on the ambulance, and the patient should be sent directly to the PPCI hospital for subsequent coronary angiography after thrombolysis. If the ambulance does not have prehospital thrombolytic therapy, the patient should be sent to a nearby non-PPCI hospital for thrombolytic therapy. After thrombolysis, the patient is transferred to the PPCI hospital for follow-up coronary angiography. For patients who arrive at a non-PPCI hospital on their own, the ECG should be completed and transmitted to the information sharing platform within 10 min after the first consultation. The PPCI hospital's cardiologist helps to make diagnosis. The confirmed STEMI patient follows the above principle direct transport to PPCI hospital or after thrombolytic therapy.

The main work content of the regional collaborative rescue system

According to the Guiding Principles for the Construction and Management of Chest Pain Centers (Trial)[24] and the “Regularization of Chest Pain Center Construction and Certification,”[23] the construction of China's STEMI Regional Cooperative Rescue System is promoted by health administrative authorities. The PPCI hospitals are the main body of construction. Its main work includes:

  1. Hospitals with PPCI and establishment of the STEMI quick rescue green channel. This includes acute chest pain preferential treatment, treatment first and then billing, PPCI team response at any time, formulating workflow diagrams for all aspects of STEMI diagnosis, differential diagnosis and reperfusion therapies, time records, team training and education, feedback mechanisms, quality control, and continuous quality improvement mechanisms
  2. Establish shared information platforms and immediate response mechanisms within the region. Through the WeChat group or other regional shared information platform for the sharing and exchange of diagnosis and treatment information, at the same time announce the key positions of the phone and response all the time
  3. Prehospital emergency system and joint treatment of various medical institutions. Signed a joint treatment agreement
  4. Joint treatment between PPCI hospitals and peripheral non-PPCI hospitals. Signed a joint treatment agreement
  5. Regional cooperative joint regular meeting system. Regular meetings are held with representatives from various units participating in the establishment of a regional collaborative rescue system. Through the sharing of various data quality indicators and processes to improve the effectiveness of analysis of existing problems and discuss solutions to make virtual regional collaborative treatment system to achieve physical operation.


The role of prehospital emergency systems in the treatment system and prehospital thrombolysis treatment workflow [Figure 3].[23]

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
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