Thrombolyse

Thrombolyse, or thrombolysis, is a medical treatment that aims to dissolve blood clots blocking vessels. It uses pharmacologic agents that activate the body's fibrinolytic system to convert plasminogen to plasmin, an enzyme that breaks down fibrin and dissolves clots. Some drugs, such as tissue plasminogen activator (tPA), are fibrin-specific and preferentially act at the clot site, while others (for example streptokinase) activate plasminogen more broadly.

Common thrombolytic agents include alteplase (a form of tPA), tenecteplase and reteplase (modified forms of tPA), and streptokinase. Thrombolysis can be administered as an intravenous infusion or, in selected cases, directly into the affected vessel via catheter-directed therapy. Treatment windows are narrow and depend on the indication: for acute ischemic stroke, thrombolysis is considered within about 4.5 hours of onset in eligible patients; for ST-elevation myocardial infarction (STEMI), systemic thrombolysis is used within 12 hours (or longer under certain criteria if percutaneous coronary intervention is not available); for massive pulmonary embolism with hemodynamic instability, thrombolysis may be indicated when there are no contraindications.

Contraindications include active or recent major bleeding, known bleeding disorders, intracranial hemorrhage or neoplasm, recent intracranial or intraspinal surgery, severe uncontrolled hypertension, and certain pregnancy or surgery histories. The principal risk is bleeding, including intracranial hemorrhage, which can be life-threatening. Other complications include reperfusion injuries and allergic reactions (notably with streptokinase).

Careful patient selection and monitoring are essential. Baseline coagulation tests, platelet counts, and blood pressure monitoring are typically performed, with repeated clinical assessments for signs of bleeding, neurologic changes, or improved perfusion.