If myocardial ischemia or acute coronary syndrome is suspected, first aid is to exclude other causes of the pain syndrome, which may indicate, for example, acute aortic dissection, rupture of the esophagus, acute myocarditis, bleeding from the upper gastrointestinal tract.
ACS begins when a destroyed atherosclerotic plaque stimulates platelet aggregation and the formation of blood clots in the coronary arteries. In a subsequent stage, a blood clot clogs a vessel, reducing myocardial perfusion. Rich in platelets, it can secrete vasoconstrictors – serotonin and thromboxane A2. This leads to a narrowing of the lumen of the vessel at the site of rupture of the atherosclerotic plaque and to even greater ischemia. The degree of clogged arteries caused by a thrombus determines the number of affected myocardium and the type of ACS:
- unstable angina pectoris – partial / intermittent occlusion, lack of myocardial damage;
- non-Q infarction – partial / intermittent occlusion, myocardial damage;
- Q-infarction – complete occlusion, myocardial damage.
Myocardial cells require oxygen and adenosine 5b-triphosphate (ATP) to maintain contractility and electrical stability. Since they are deprived of it, anaerobic glycogen metabolism occurs, less ATP is formed, which leads to a failure of sodium-potassium and calcium pumps and the accumulation of hydrogen and lactate ions.
Classification of acute coronary syndrome allows you to divide patients into two groups:
- Patients with chest pain lasting more than 20 minutes, which cannot be relieved by taking nitroglycerin. On the ECG – ST segment elevation, which indicates acute coronary artery occlusion. In the future, this leads to the occurrence of Q-infarction.
- Patients with chest pain lasting more than 20 minutes, which cannot be relieved by taking nitroglycerin, and patients with class III angina pectoris that first appeared without a steady ST segment elevation (depression, T change). This condition transforms into non-Q-infarction or into unstable angina.
First of all, the diagnosis of ACS begins with the collection of anamnesis and detailing of complaints: prolonged (more than 20 min.) Intense chest pain of a pressing nature, shortness of breath, fear of death – a similar symptom complex practically does not occur in other heart pathologies. The main purpose of a physical examination is to exclude pains of non-cardiac origin , non-ischemic heart diseases, as well as any pathologies that potentially contribute to the increase in ischemia.
An electrocardiogram (ECG) at rest – is the “golden method” of diagnosing ACS, as well as a screening method for other diseases accompanied by pain. An ECG at rest must be compared with a preliminary cardiogram and with an ECG after the disappearance of pain. Another advantage of this method is the ease of execution – patient management is available both in the hospital, in the clinic, and in the family type outpatient clinic.
During myocardial death, heart cells die. Enzymes from cardiomyocytes enter the bloodstream and continue to circulate in it for some time. Using special tests, you can determine the concentration of these substances, assess the degree of damage, and also establish the fact of necrotic changes in the heart muscle.
Markers of necrotic changes in the myocardium are:
- Creatine phosphokinase (MV).
Echocardiography – this method is widely used to clarify the diagnosis, but is not suitable for making it, since it does not allow you to see small foci of necrosis.
Signs of ACS are:
- Pathological valve function.
- Enlarged chambers of the heart.
- Turbulent blood flow.
- Enlarged inferior vena cava.
This method is used if it is necessary to determine the exact localization of the necrotic focus. Its essence is that healthy and damaged cells have different biochemical activity. With the introduction of special reagents, the latter will accumulate selectively in either healthy or dead cells (depending on the reagent), which will accurately determine the presence of damaged areas.
Coronarography is a rather complicated, but quite informative method for the study of ACS. Its essence is the implementation of an x-ray image after the administration of a contrast agent into the coronary arteries. Coronarography allows you to determine the exact location and degree of narrowing of the affected artery.
Mandatory (standard) diagnostic measures for suspected ACS are an electrocardiogram and determination of necrosis markers. The rest are prescribed if necessary – depending on the specifics of the disease in each patient.
Treatment and care
If acute coronary syndrome is suspected, first aid and mandatory hospitalization are prerequisites for a favorable outcome and the exclusion of further complications. The provision of emergency care, as well as transportation of the patient with an acute heart attack, is carried out in a prone position with a slightly raised head. We list the stages of first aid.
- Nitroglycerin under the tongue. This is the first aid for heart failure, as well as acute coronary syndrome, you can take nitroglycerin if necessary every 5-10 minutes.
- Acetylsalicylic acid (chew tablet 160-325 mg).
- Oxygen therapy. Inhalation with moistened oxygen using a mask or nasal catheter (flow rate 4-6 l / min.).
- Anesthesia. Nitroglycerin (under the control of blood pressure) intramuscularly with diphenhydramine. Morphine intramuscularly 1% (1:20 saline).
- Heparin (5 thousand units).
- Further tactics depend on the data of the electrocardiogram.
Coronary heart disease significantly increases the likelihood of developing myocardial infarction, can lead to sudden death. It is expressed in a change in the nature of angina attacks.
The term “acute coronary syndrome” was introduced due to the impossibility of quickly distinguishing between non-standard angina pectoris and myocardial infarction, the need to follow certain treatment algorithms and provide first aid for acute coronary syndrome until a final diagnosis is established.
Diagnosis of acute coronary syndrome and, depending on its results, first aid is based on the diagnosis of myocardial infarction and unstable angina: the clinical picture, changes in the electrocardiogram, as well as laboratory diagnostics.
Emergency care for acute coronary syndrome depends on its variant and is carried out on the basis of specially developed protocols. In ACS with ST segment elevation:
- Patients hospitalized no later than 12 hours after the onset of symptoms are indicated for mechanical (percutaneous coronary intervention (PCI) or pharmacological reperfusion).
- PCI is preferred if it is produced no later than 120min. After the first call for medical help.
- If it is impossible to perform PCI for 120 minutes. Thrombolysis therapy is performed.
- In case of successful thrombolysis, the patient is sent to the center for coronary angiography for 3-24 hours. In case of ineffective thrombolysis, urgent angiography is necessary.
- Antiplatelet and anticoagulant therapy.
- Lipid-lowering therapy.
The help algorithm for ACS without ST segment elevation:
- Assessment of the clinical condition, confirmation of the diagnosis.
- Drug therapy: anti-ischemic drugs, anticoagulants and antiplatelet agents.
- Coronary revascularization.
Nitroglycerin is a vasodilator that reduces myocardial oxygen demand. It is administered sublingually or using a buccal spray (0,3-0,6 mg) every 5 minutes, for a total of 3 doses. If the pain persists, the administration of intravenous nitroglycerin should be started (initial rate of 5-10 μg / min with its increase to 10 μg / min every 3 to 5 minutes until the symptoms subside). An absolute contraindication to the use of nitroglycerin is hypotension.
Morphine and other analgesics
Morphine is recommended after 3 doses of nitroglycerin, or when symptoms of ischemia recur during treatment. In such cases, from 1 to 5 mg of morphine sulfate can be administered intravenously every 5-30 minutes if necessary, with close monitoring of blood pressure and respiratory rate. Morphine acts as a powerful analgesic.
β-blockers inhibit β-1 adrenergic receptors in the myocardium, reduce its contractility and heart rate. In the absence of contraindications, therapy with oral forms of β-blockers should be started within the first 24 hours. For all patients, the dose should be adjusted to achieve a heart rate of 50 to 60 beats per minute.
In foreign recommendations, it was noted that in the absence of hypotension or other known contraindications, the oral administration of an angiotensin converting enzyme inhibitor (enalapril, lisinopril) or an angiotensin II receptor blocker, for patients who do not tolerate ACE inhibitors (valsartan, losartan) during the first 24 hours, significantly reduced number of deaths.
Antithrombotic therapy is the cornerstone of the treatment of patients with ACS. It includes two components: antiplatelet and anticoagulant therapy.
Aspirin. It blocks the synthesis of thromboxane A2 by irreversibly inhibiting cyclooxygenase-1, thereby reducing platelet aggregation. The initial daily dose should be from 162 to 325 mg, and then reduced – from 75 to 162 mg. Used for long-term secondary prevention.
Clopidogrel is the recommended alternative for patients who cannot tolerate aspirin. It reduces platelet activation and aggregation and reduces blood viscosity. The loading dose is 600 mg, the supporting dose is 75 mg per day. Clopidogrel and aspirin therapy is recommended for almost all patients with ACS.
Anticoagulant therapy should begin as soon as possible after diagnosis. To date, such preparations are used for its implementation: unfractionated heparin, enoxaparin, fondoparinux.
Unfractionated Heparin (UFH). The results of several randomized trials indicate that UFH is associated with lower mortality rates than aspirin therapy alone. But when it is prescribed, monitoring of activated partial thromboplastin time (PTT) is necessary to prevent hemorrhage.
Fondoparinux is a synthetic pentasaccharide that is an indirect inhibitor of factor XA and requires antithrombin to achieve a therapeutic effect. This drug is preferable to other anticoagulants for patients undergoing conservative therapy and in patients with an increased risk of bleeding.
In the absence of contraindications, lipid-lowering therapy with statins should be started for all patients with ACS, regardless of baseline cholesterol and LDL.
It is carried out at the prehospital stage. If this is not possible, no later than 30 minutes after hospitalization. The following types of drugs are used:
- Streptokinase – 1,5 million, I / O OD for 30-60 min;
- Alteplase – 15 mg IV bolus, 0,75 mg / kg body weight for 30 minutes, then 0,5 mg / kg for 60 minutes .; total dose should not exceed 100 mg;
- Tenectoplase – a bolus in / in the introduction of the drug depends on the weight of the patient: 30 mg with a mass of less than 60 kg; 35 mg per 60-69 kg; 40 mg per 70-79 kg; 45 mg per 80-89 kg; 50 mg per weight more than 90 kg.
Surgical treatment of acute coronary syndrome is aimed at restoring blood circulation in the coronary arteries. Allow this to achieve coronary artery bypass grafting and stenting. The essence of the first method is to create a workaround for arterial blood, avoiding the affected area. Thus, those parts of the heart that suffered from hypoxia begin to function normally again. The essence of stenting is the placement of a stent in the artery, which will expand the contracted area and will prevent further plaque growth.
Rehabilitation and follow-up of the patient
Heart rehabilitation includes:
- dietary counseling;
- the appointment of a set of exercises;
- psychosocial support;
- to give up smoking;
The goal is to quickly and completely restore the body and reduce the likelihood of a repeat ACS. The rehabilitation program focuses on improving physical condition, self-confidence and social inclusion. It is carried out with the help of a doctor, specialized physiotherapists, nurses and is divided into hospital and outpatient stages. In addition, constant consultation with the attending doctor is necessary.
Over the past quarter century, tremendous successes have been achieved in our understanding of the pathophysiology of ACS, and these achievements have been accompanied by huge breakthroughs in the management of this condition. Accurate diagnosis of acute coronary syndrome has vital consequences and requires a thorough assessment of the patient’s history, results of a physical examination, 12-lead ECG, and analysis of heart biomarkers.