Thrombolysis
The thrombolysis (v Greek.. Thrombus "blood clot" analysis in medical jargon - "Resolution") thrombolytic therapy or shortly lysis called - is a medical therapy to re-by clots dissolve occurred closures of blood vessels.
The method can be used for the treatment of heart attack (myocardial infarction), pulmonary embolism , ischemic stroke and even when a thrombosis has been identified that could potentially cause it.
The substances used activate plasmin , an enzyme in the body's own fibrinolysis (fibrin breakdown).
Pathophysiology
Heart attacks, pulmonary embolisms, and ischemic strokes can be triggered by blood clots ( thrombi or embolisms ) that block the blood vessels in the affected organs (heart or brain). The consequence of this closure is that the area supplied by the vessel can no longer be flowed through by blood and is therefore threatened by a heart attack . A relevant pulmonary embolism also leads to acute heart failure due to the lack of return flow of blood to the heart.
application
Medicines used for lysis consist of enzymes that can break down this thrombus or embolus, or of substances that activate an endogenous breakdown enzyme ( plasminogen ) and thus keep the bloodstream free again. It can be administered intravenously as systemic lysis and in special cases via a catheter intraarterially as local lysis. The earlier it is lysed, the greater the chances of success. In patients with circulatory instability and pulmonary embolism, the emergency doctor can start the thrombolysis. This is also the case with heart attacks if a cardiac catheter center cannot be reached promptly (within 90 to 120 minutes). New studies are shortening the time even further; fibrinolysis is a good alternative to percutaneous transluminal coronary intervention (PCI) if the symptoms of myocardial infarction (STEMI) started a maximum of three hours ago and the transport to a hospital would take longer than an hour.
If a certain period of time is exceeded, the dangers outweigh the benefits, as the tissue may already be necrotic . Reference values used to be three hours after the onset of stroke symptoms, and up to four and a half hours after the onset of stroke symptoms according to new studies, and six hours for heart attacks, after which thrombolysis is usually no longer useful.
Side effects
Since the therapy also dissolves or prevents useful blood clotting , the patient is at risk of serious complications from bleeding. Cerebral haemorrhage is one of the most serious side effects and has a frequency of about 1%.
With a heart attack, arrhythmias can occur even after successful thrombolysis therapy. For these reasons, a patient must be closely monitored even after the lysis therapy.
Active ingredients used - fibrinolytics
Either the (older) enzymes streptokinase or urokinase or the so-called “modern fibrin-specific thrombolytics” such as alteplase (rt-PA), reteplase (r-PA) or tenecteplase (TNK-tPA) are used as so-called non-specific thrombolytics .
Contraindications
The contraindications to lysis therapy must be considered in the context of a risk-benefit analysis and with a view to alternative therapeutic methods (interventional procedures).
In general, acute bleeding or coagulation disorder with thrombocytopenia or with oral anticoagulation, major injury or surgery in the last three months, tumors , dissecting aortic aneurysms as well as previous or suspected acute cerebral haemorrhage and strokes as well as the puncture of a large artery or lumbar puncture are considered absolute contraindications . Before performing lysis therapy for strokes, it is therefore mandatory to perform a computed tomography of the skull in order to rule out active bleeding.
literature
- Karow, Lang-Roth: General and special pharmacology and toxicology. 14th edition 2005.
Individual evidence
- ^ Paul W. Armstrong, Anthony H. Gershlick, Patrick Goldstein, Robert Wilcox, Thierry Danays, Yves Lambert, Vitaly Sulimov, Fernando Rosell Ortiz, Miodrag Ostojic, Robert C. Welsh, Antonio C. Carvalho, John Nanas, Hans-Richard Arntz , Sigrun Halvorsen, Kurt Huber, Stefan Grajek, Claudio Fresco, Erich Bluhmki, Anne Regelin, Katleen Vandenberghe, Kris Bogaerts, Frans Van de Werf: Fibrinolysis or Primary PCI in ST-Segment Elevation Myocardial Infarction. In: New England Journal of Medicine. 2013, p. 130312110331000, doi: 10.1056 / NEJMoa1301092 .
