Thrombolysis: everything you need to know about this emergency medication

Thrombolysis is the administration of a thrombolytic drug in intensive care to unclog a life-threatening clogged blood vessel.

There thrombolysis is the emergency drug treatment ofcerebrovascular accident (CVA) of ischemic origin. But this technique is also used in case of obstruction of an arterial vessel whether in case ofmyocardial infarctionofpulmonary embolism or even of lower limb thrombosis.

In case of myocardial infarction, thrombolysis is a standard first-line treatment. It is an alternative toangiography by balloon (procedure aimed at widening an artery, narrowed or obstructed by a deposit of atheroma plaque) more invasive.

In ischemic stroke, thrombolysis should be administered by intravenous route as soon as possible either within 4 and a half hours after the first signs of stroke. In case of blockage of a large blood vessel, thrombolysis is usually combined with mechanical thrombectomy which removes a clot using a mechanical device.

The patient is taken care of by the emergency services (SAMU, firefighters, etc.). He is taken to the hospital where he is quickly taken care of. He will then have to endure a series of tests (Brain MRIelectrocardiogram, coronary angiographyblood test, etc.).

Once the diagnosis is confirmed, the drug is given by injection into a vein. This painless injection lasts about 1 hour (but sometimes the intervention can last many hours).

The molecule is carried by the blood to the clogged artery. Under the effect of thrombolysis, the clot will then disintegrate. The residues of the clot will be eliminated by the blood flow.

Thrombolysis is often associated with a anticoagulant treatment to avoid bleeding.

In case of stroke, if a large vessel is obstructed, thrombolysis should be immediately followed by a mechanical thrombectomy. This intervention consists of recanalizing a cerebral artery occluded in the acute phase of ischemic stroke, using a mechanical clot removal device introduced by the endovascular route under radioscopic control. This arterial recanalization allows reperfusion and revascularization of the suffering cerebral parenchyma.

The patient’s blood pressure, pulse and cardiac and neurological status are monitored continuously for 24 to 48 hours in the intensive care unit.

Depending on the patient’s state of health and needs, rehabilitation can start as soon as the patient returns to his room. The speed of these interventions has a direct impact on the patient’s recovery.

Thrombolysis can be used in several cases of obstruction of an artery:

In the latter case, the treatment must be taken within 4.5 hours after the onset of symptoms.

A thrombolytic (also called “fibrinolytic“) makes it possible to induce thrombolysis (or fibrinolysis). These molecules which act at the level of a blood clot by transforming plasminogen into plasmin. Plasmin is an enzyme capable of degrading fibrin, which is the protein involved in clot formation. Thus the blood vessel is unobstructed, which restores the blood circulation necessary for the delivery of oxygen and nutrients to the organs.

• First-generation thrombolytics: streptokinase (Steptase®) andurokinase (Actosolv® and Therasolv®).
• Second-generation thrombolytics: alteplase (Actilyse®), tenecteplase (Métalyse®) and reteplase (Rapilysin®).

The second generation molecules are more specific, their action is faster and less allergenic than those of the first generation.

There are several absolute or relative contraindications to the performance of thrombolysis.

Among absolute contraindications it must be mentioned :

• bleeding less than 3 months old;
• an evolving digestive ulcer;
• surgery less than 10 days old;
• an intracranial or spinal cord intervention less than 6 months old;
• a stroke less than 2 years old;
• head trauma less than 3 months old;
• an intracranial tumor or vascular malformation;
• a kidney or liver biopsy less than 15 days old;
• severe hemostasis pathology;
• pregnancy or postpartum;
• severe and uncontrolled high blood pressure;
• suspected aortic aneurysm (pocket that can rupture) or pericarditis (inflammation of the membrane that surrounds the heart).

We hear by relative contraindicationscases that can be discussed with a doctor:

• liver or kidney failure;
• a hemorrhagic tumor;
• treatment with an antivitamin K (anticoagulant), an antiplatelet agent (acetylsalicylic acid, clopidogrel), a nonsteroidal anti-inflammatory drug (ibuprofen);
• diabetes with retinal disease (retinopathy);
• recent trauma to the heart muscle.

In addition, thrombolytics should not be combined with iodinated contrast products (products used for carrying out diagnostic examinations such as MRI).

Finally, the combination of a thrombolytic based on alteplase or urokinase and an enzyme-converting enzyme inhibitor (antihypertensive) is contraindicated because it promotes the appearance of angioedema (swelling under the skin). skin).

For ischemic stroke, thrombolysis is effective in 30% of cases. It also decreases by 30% risk of severe disability post stroke. Finally, the hemorrhagic risk is also reduced by 5%.

For myocardial infarction, thrombolysis carried out within the first six hours of the infarction makes it possible to reduce mortality by almost 30%. Nevertheless, angioplasty is a technique that is more effective. It has a success rate of coronary recanalization very much higher than that of thrombolysis, around 96%.

Regarding thromboses and pulmonary embolism, evidence suggests that thrombolytic agents may dissolve blood clots faster than heparin and may reduce the mortality rate associated with pulmonary embolism.

Thrombolysis carries risks:

• Hemorrhages in the brain, intestines, urine, nose…;

• Allergic reactions to the drug: swelling in the throat and lips, difficulty swallowing…;
• Drops in blood pressure (malaise);
• Heart rhythm disorders.