Thrombolysis with myocardial infarction at the prehospital stage

It is difficult to overestimate the importance of timely thrombolysis in case of myocardial infarction. This procedure can significantly reduce mortality and disability in the case of this dangerous disease.

What it is?

Thrombolysis with myocardial infarction is a medical procedure for introducing a particular enzyme preparation into the vascular bed of a person, which helps to dissolve a blood clot that impedes normal blood circulation. Currently, a sufficiently large number of drugs have been developed that are used for thrombolysis therapy. Every year the number of these procedures in everyday medical practice only increases. This can significantly increase the survival and quality of life of patients with myocardial infarction. If thrombolysis was not performed, then after treatment people often have to go on a disability.

Indications for use in myocardial infarction

Over time, the set of clinical conditions is corrected, in which thrombolysis therapy is recommended. Currently, indications for thrombolysis in myocardial infarction are as follows:

• the presence of an increase in the ST segment on electrocardiography, as well as other signs of acute myocardial infarction;
• no more than 12 hours since the onset of ischemic pain;
• first appeared complete blockade of the right leg of the bundle of His against the background of ischemic pain in the sternum.

If all these conditions are met, then the medical worker begins to carry out thrombolysis with myocardial infarction. An assessment of the possibility of carrying out this procedure should be performed at the first contact of the patient with characteristic complaints with a medical professional.

Absolute contraindications

This procedure is considered quite complicated and is not always easily tolerated by patients. Doctors have established a list of conditions that may impede its implementation. To date, the following absolute contraindications to thrombolysis with myocardial infarction are distinguished:

1. The presence of a stratified aortic aneurysm.
2. A history of hemorrhagic stroke less than 6 months ago.
3. Violations of the blood coagulation system.
4. Arterial hypertension resistant to antihypertensive therapy (with the help of drugs it is not possible to reduce the level of systolic blood pressure below 220 mm Hg, and diastolic below 110 mm Hg).
5. Surgery less than 3 weeks ago.
6. Gastrointestinal bleeding less than 1 month ago.
7. Traumatic brain injury less than 3 weeks ago.

In all these conditions, thrombolysis therapy is not carried out. This is due to the fact that the risk of developing serious, life-threatening complications is greater than the positive effect of the procedure.

Relative contraindications

There are situations in which thrombolysis therapy is undesirable, but it is possible in cases where the intended benefits of the procedure exceed the possible harm from it.

To date, the following relative contraindications to thrombolysis with myocardial infarction are distinguished:

1. Transient ischemic attacks less than 6 months ago.
2. Pregnancy.
3. The postpartum period (less than 28 days after the resolution of pregnancy).
4. Continuous use of direct anticoagulants.
5. Long - term cardiopulmonary resuscitation, accompanied by trauma to the patient.
6. The presence of gastric ulcers in the acute stage.
7. Liver failure.
8. Infectious endocarditis.
9. Puncture of large vessels, inaccessible for compression.
10. Any retinal hemorrhage.

Despite a large number of relative contraindications, most often doctors carry out thrombolysis with myocardial infarction, regardless of their presence, since without this procedure there is a high probability of developing the most serious consequences for patients.

Feasible side effects

This procedure often proceeds quite hard for the patient. Adverse reactions develop in approximately 1% of patients undergoing thrombolysis with myocardial infarction. Among the most common side effects are:

• severe headache;
• increase in body temperature;
• the development of atrial fibrillation (at the same time, it is evaluated as an indicator of the restoration of blood flow in the myocardium);
• development of bleeding at the injection site;
• allergic reactions.

The complexity of the procedure, as well as the possible development of side effects, are some of the reasons why thrombolysis during myocardial infarction is most often performed in the intensive care unit (if the patient is in a hospital).

Success criteria for the procedure

If thrombolysis is successful, then the following phenomena are observed:

1. The patient quickly decreases, and then the pain disappears.
2. The return of electrocardiography to normal.
3. The development of atrial fibrillation (atrial fibrillation) during thrombolytic therapy.
4. A return to normal levels of indicators of cardiospecific biochemical markers of necrosis.

Also, during the course of thrombolysis, the general condition of the patient and other indicators of his health (heart rate, respiration, blood pressure and others) are evaluated.

Preparations for thrombolysis

Over the past decades, the main drug for thrombolysis was the drug Streptokinase. It belongs to the group of direct tissue plasminogen activators. This drug is relatively cheap, but not effective enough, and it often causes the development of serious side effects. Currently, indirect tissue plasminogen activators have become more widespread, the main of which are:

• Alteplaza.
• "Tenecteplase".
• Actilize.

Thrombolysis with myocardial infarction, carried out by indirect tissue plasminogen activators more often passes without negative reactions and has good efficiency. Their main disadvantage is the relatively high cost in comparison with the drug Streptokinase.

The mechanism of action of drugs

These drugs provide binding of the enzyme to plasminogen located on fibrin. Under the influence of drugs, plasminogen turns into plasmin, while penetrating into fibrin. In the future, plasmin destroys fibrin, thereby ensuring the breakdown of the thrombus.

When thrombolysis is performed, microthrombi can form. The introduction of tissue plasminogen activators also contributes to an increase in platelet activity. All this requires concomitant antiplatelet therapy.

Procedure for medical personnel

Today, thrombolysis with myocardial infarction at the prehospital stage is often practiced. A drug like Tenecteplase is best suited for this. It differs from other direct tissue plasminogen activators in its low probability of developing complications, as well as its ease of use. "Tenectoplase" is injected intravenously.

"Alteplase" is also sometimes used for thrombolysis with myocardial infarction at a prehospital level. Before its use, the patient is administered 5000 IU of heparin. Then 15 ml of Alteplase is administered bolus intravenously. After that, 0.75 ml of the drug per each kilogram of patient weight is administered dropwise to the patient for 30 minutes. In this case, the patient is constantly injected with heparin.

Streptokinase is recommended to be administered only in a hospital setting. When using this drug, thrombolysis with myocardial infarction is performed in the intensive care unit. The patient is administered intravenously drip 1,500,000 units of the drug diluted in 100 ml of physiological saline for 0.5-1 hours. In the case of this medication, heparin in the amount of 5000 units is also used before its administration. Subsequently, heparin is used no less than 4 hours after the end of the Streptokinase infusion.

On each form of the thrombolysis protocol for myocardial infarction, it is indicated that this procedure should be performed no later than 12 hours after the onset of the first symptoms of the disease. After thrombolysis therapy, it is necessary to be delivered to a specialized hospital within 12 hours for the purpose of stenting or balloon angioplasty. Compliance with this order significantly increases the patient's chances of a positive outcome of the disease.

What should the patient do?

Myocardial infarction usually develops in cases where the patient already has another cardiovascular pathology. Most often, this disease is characterized by severe pain in the sternum, accompanied by radiation to the left shoulder, hand, shoulder blade, abdomen or neck, as well as severe weakness. If these symptoms occur, the patient is recommended to call an ambulance team, then measure blood pressure and, if its level is at least 120/80 mm. Hg. Art. take a nitroglycerin tablet. If after 5 minutes the pain has not disappeared, and the SMP team has not arrived yet, it is necessary to repeat the use of this drug. In addition, it is recommended to take 500 mg of acetylsalicylic acid (aspirin).

What will the healthcare provider do?

In the case of a paramedic or doctor of the ambulance team, these employees must perform the following actions before starting thrombolysis therapy:

1. Clarify the patient's time of occurrence and the nature of the pain syndrome.
2. Perform electrocardiography to clarify the diagnosis of myocardial infarction and measure blood pressure.
3. In the case of this diagnosis, the patient is given a tablet of nitroglycerin, Aspirin (if he has not taken it earlier).
4. Subsequently, he is transferred to the ambulance when lying down.
5. Already during transportation to the hospital, the effect of taking nitroglycerin (5 minutes) is evaluated.
6. Also, the patient is given 5000 IU of heparin, at least 40 mg of statins (Atorvastatin, Rosuvastatin, Lovastatin) and drugs from the group of beta-blockers (Metoprolol, Bisoprolol, Carvedilol) and ACE inhibitors ( "Enalapril", "Lisinopril", "Perindopril", "Ramipril") in a dosage that will not lower the level of blood pressure less than 110/70 mm. Hg. Art. and heart rate less than 50 beats / min.
7. In the future, the medical worker clarifies the presence of contraindications for thrombolysis. If they are absent, then this procedure begins.

In cases where a stationary health care facility is located near the place of emergency call, thrombolysis is most often performed in the intensive care unit in order to reduce the likelihood of serious complications and to stabilize the patient most quickly when they occur.

In the hospital, thrombolysis therapy is carried out under the constant supervision of a cardiologist / general practitioner and resuscitation doctor.

After the procedure, doctors stabilize the patient's condition and transfer to a specialized healthcare institution in order to perform angioplasty or stenting. After discharge from the hospital, the patient is sent to the outpatient stage of treatment, where he is recommended to take the following medications:

• "Clapidogrel";
• "Aspirin";
• drugs from the group of beta-blockers;
• drugs from the group of ACE inhibitors;
• peripheral vasodilators (drugs that expand the coronary vessels).

These drugs significantly reduce the likelihood of recurring myocardial infarction. In the future, with a satisfactory condition of the patient, as well as the presence of sufficient recovery potential (the patient is not too old, able to move, accessible to productive contact) he is sent for rehabilitation, in order to restore normal life. In cases when it comes to young people, they are often sent to a rehabilitation course immediately after the inpatient phase of treatment.

Forecast

If the dosages of the drugs are observed, thrombolysis with myocardial infarction in the vast majority of cases is successful. Even when using streptokinase, the number of serious complications does not exceed 2%. These performance indicators are relevant in cases where all recommendations of thrombolysis with myocardial infarction are followed.

Despite this procedure, the further quality of life of the patient will largely depend on the completeness and timeliness of other medical and rehabilitation measures. After thrombolysis, patients are advised to undergo a course of treatment in cardiology departments with possible angioplasty or stenting. Rehabilitation includes physical therapy courses, scheduling the necessary physical activity, as well as regular medications.