Trombolysis of A.Griguolo

Generality

Thrombolysis is the pharmacological treatment that allows dissolving a thrombus or an embolus, present in an artery or in a vein.

Implemented by specialized medical figures, thrombolysis involves the administration of particular drugs, called fibrinolytics (or thrombolytics), and an X-ray instrumentation to observe the outcome.

Thrombolysis is used when it is necessary to dissolve a thrombus or an embolus responsible for conditions, such as: deep vein thrombosis, myocardial infarction with ST segment elevation, ischemic stroke, peripheral acute ischemia and pulmonary embolism.

Thrombolysis presents some risks (including: bleeding, infection and allergic reaction to the drug used) and several contraindications.

Thrombolysis is effective in a considerable proportion of treated patients.

A quick review of what is a Thrombus?

In medicine, any abnormal blood clot attached to the inner wall of an artery or vein is called thrombus .

The thrombi derive from unusual coagulation reactions, which may depend on various factors, including: tobacco smoke (smoking), hypercholesterolemia, overweight / obesity, stress, atherosclerosis, diabetes mellitus, sedentary lifestyle, some malignant tumors, some infectious diseases, pregnancy etc.

The presence of a thrombus in a blood vessel is dangerous, because it is an obstacle to the blood flow, sometimes in a way so marked as to block blood circulation; the thrombi are also dangerous, because they can break, giving rise to mobile fragments that can travel in the blood and wedge themselves into blood vessels even very far from the starting site.

Known as the embolism (while the fragments are called emboli ), this last phenomenon is among the main causes of important medical conditions, such as obstructed coronaries, pulmonary embolism and stroke.

Blood coagulation involves platelets and so-called coagulation factors.

What is thrombolysis?

Thrombolysis, or thrombolytic therapy, is the treatment based on drugs, which serves to dissolve the thrombi or emboli present in arterial or venous blood vessels, in order to:

Improve blood flow (or blood circulation), where there are impediments;
Prevent damage to organs and tissues, which can result from blood deprivation (in particular, this is the case of thrombi present in the arteries).

uses

Thrombolysis can be used when there is a need to dissolve thrombuses or emboli responsible for:

Myocardial infarction with ST-segment elevation It is a severe form of heart attack, due to the complete blockage of one of the main coronaries and characterized by a very particular electrocardiogram (in which the ST segment occupies a higher position than normal).
In myocardial infarction with elevation of the ST tract, the myocardium has not yet undergone necrosis (that is, to death), but is developing a lesion that will have this outcome, if no help is provided (and, in this case, if it does not apply a treatment like thrombolysis).

Deep venous thrombosis in a leg.

Deep vein thrombosis . It is the pathological condition that results from the formation of a thrombus in a deep vein of the human body.
With a preference for the venous system of the lower limbs, deep vein thrombosis is very dangerous, because they block the blood flow along the involved vein and / or give origin to emboli that, returning to the heart through the blood, can give rise to episodes of pulmonary embolism.
Factors such as: too tight clothing, advanced age, the maintenance of a static position for long periods of time, obesity, the use of the contraceptive pill, the genetic predisposition to thrombotic phenomena, a sedentary lifestyle and smoking.
Ischemic stroke . In medicine, the term "stroke" and its synonyms " apoplectic stroke ", " cerebral infarction " and " stroke " indicate death (or necrosis), due to lack of blood supply, of a more or less extensive area of brain.
Ischemic stroke is a particular type of stroke, in which the lack of blood supply to the brain is the result of severe narrowing or total occlusion of an artery in the brain circulatory system.
Representing 85% of stroke cases, ischemic stroke can be thrombotic or embolic; it is thrombotic, when the vasal narrowing / occlusion depends on a thrombus, while it is embolic, when the vasal narrowing / occlusion depends on an embolus.
Pulmonary embolism . It is the medical condition, characterized by the obstruction of one of the pulmonary arteries, or the blood vessels responsible for transporting deoxygenated blood from the right ventricle of the heart to the lungs, with the aim of oxygenating it.
Pulmonary embolism represents a very dangerous pathological state for those affected, as it drastically affects the vital process of oxygenation of the blood in the lung.
The main cause of pulmonary embolism due to thrombolysis is deep vein thrombosis.
Acute peripheral ischemia . Also known as acute limb ischemia, it is the sudden and sudden reduction in blood flow ("acute ischemia") within the arterial vascular network present at the extremities of the human body ("peripheral").
With a particular preference for the lower limbs, acute peripheral ischemia can be of a thrombotic nature (when it depends on a thrombus) or embolic (when it depends on an embolus).

Preparation

Thrombolysis does not impose any particular preparation on the patient.

How to do it

Thrombolysis is a medical treatment that focuses on the administration of particular drugs and involves the use of radiological imaging techniques (in simpler words, X-ray instruments) to confirm the dissolution of thrombus or target embolus.

Method of administration: what are they?

Depending on the circumstances, the doctor who practices thrombolysis may choose to infuse the pharmacological preparation by a simple intravenous injection or directly where the thrombus or target embolus resides .

If he opts for simple intravenous injection, he uses a small catheter, which inserts into a point of venous access comfortable for the injection procedure (eg: vein of the arm); if instead it opts for the infusion at the exact point where the thrombus or target embolus resides, it uses a long catheter, which introduces it into the vascular system and leads to the desired point.

Did you know that ...

Under conditions such as stroke, myocardial infarction with ST-segment elevation and pulmonary embolism, the implementation of thrombolysis must take place within a certain amount of time (usually 2-3 hours) from the compromised blood flow from the thrombus or embolus, otherwise the drug administration has no effect.

Drugs: what are they?

Thrombolysis involves the use of fibrinolytic drugs (or thrombolytic agents ).

The fibrinolytics most frequently used for thrombolytic therapy are:

Streptokinase;
The anestreplasi;
The tenecteplase;
The reteplase;
The urokinase;
Recombinant tissue plasminogen activators (eg: alteplase).

HOW DO THE FIBRINOLITIC DRUGS ACT?

The process of blood coagulation, which triggers for example on the occasion of a skin wound, involves numerous proteins; among these, fibrin stands out, which, forming a sort of net, has the task of trapping the platelets and generating the clot that will block the leakage of blood.

During normal coagulation, the fibrin is finely controlled in its action, in the sense that, when the curd is formed, a system intervenes that blocks its production; if this were not the case, we would witness the formation of abnormal blood clots, or the generation of thrombus.

Fibrinolytic drugs act through the activation of plasminogen in plasmin, which is the protein specifically assigned, during a coagulation process, to degrade fibrin, when the latter is no longer necessary.

To simplify as much as possible, thrombolysis drugs work by activating the protein in the human body, which intervenes when blood clotting needs to be stopped.

The term "fibrinolytic" derives from the word "fibrinolysis", in which "lysis" means disintegration / destruction, while "fibrino" refers to fibrin.

Therefore, "fibrinolysis" and derived adjectives, such as "fibrinolytic", mean, literally, "destruction of fibrin".

How long does thrombolysis last?

Thrombolysis can last a few hours, if the thrombus or the embolus to be dissolved is of small size, or some days, if the thrombus or the embolus to be dissolved is of large size.

In essence, therefore, the magnitude of the dangerous blood clot affects the duration of thrombolysis: the larger the latter, the longer the administration times of the fibrinolytic drug.

Who performs thrombolysis?

Thrombolysis is a pharmacological treatment in which several medical specialists are prepared, including:

Interventional radiologists;
Vascular surgeons;
Cardiologists;
Interventional neuroradiologists;
Neurosurgeons.

Risks and Complications

Thrombolysis presents some risks; specifically, the patient who undergoes it could:

Develop an allergic reaction to the fibrinolytic drug used;
Develop an infection at the catheter insertion point for drug administration;
Being the subject of more or less serious bleeding ;
Suffering damage to the blood vessels crossed by the catheter for direct administration of the fibrinolytic drug;
Being the victim of a hemorrhagic stroke with a potentially fatal outcome. It is the most serious, but also the least common (in fact, only 1% of patients) complications.

Currently, the techniques of implementation and monitoring of thrombolysis ensure that the latter proceeds safely . Therefore, in general, it is very rare to observe the complications described above.

Contraindications

Thrombolysis has some contraindications; in fact, this drug treatment cannot be performed in the presence of:

Use of anticoagulant drugs (or blood thinner);
Severe hypertension;
Serious bleeding;
Hemorrhagic stroke;
A severe kidney disease;
A major recent surgery;
Aortic dissection;
A severe liver disease;
Acute pancreatitis;
Infective endocarditis.

Furthermore, thrombolysis is not suitable for pregnant women and those of very advanced age.

Results

Thrombolysis is a procedure that is good but not optimal; according to statistics, in fact, 25% of patients do not get the hoped-for benefits and 12% are victims of a relapse (ie the abnormal blood clot reforms after an initial thrombolysis success).