Thrombolysis is the breakdown (lysis) of blood clots formed in blood vessels, using medication. It is used in ST elevation myocardial infarction, stroke, and very large pulmonary embolisms. The main complication is bleeding (which can be dangerous), and in some situations thrombolysis may therefore be unsuitable. Thrombolysis can also play an important part in reperfusion therapy that deals specifically with blocked arteries.
1 Medical uses 2 Contraindications
2.1 Myocardial infarction 2.2 Stroke
3 Side-effects 4 Agents 5 Research 6 See also 7 References
Medical uses Diseases where thrombolysis is used:
ST elevation myocardial infarction: Large trials have shown that mortality can be reduced using thrombolysis (particularly fibrinolysis) in treating heart attacks. It works by stimulating secondary fibrinolysis by plasmin through infusion of analogs of tissue plasminogen activator (tPA), the protein that normally activates plasmin. Stroke: Thrombolysis reduces major disability or death when given within 3 hours (or perhaps even 6 hours) of ischaemic stroke onset when there are no contraindications to treatment. Massive pulmonary embolism. For the treatment of a massive pulmonary embolism, catheter-directed therapy is a safer and more effective alternative to systemic thrombolysis. This involves the injecting of drugs directly into the clot. Severe deep vein thrombosis Acute limb ischaemia
Apart from streptokinase, all thrombolytic drugs are administered
together with heparin (unfractionated or low molecular weight
heparin), usually for 24 to 48 hours.
Thrombolysis is usually intravenous. It may also be used directly into
the affected blood vessel during an angiogram (intra-arterial
thrombolysis), e.g. when patients present with stroke beyond three
hours or in severe deep vein thrombosis (catheter-directed
Thrombolysis is performed by many types of medical specialists,
including interventional radiologists, vascular surgeons,
cardiologists, interventional neuroradiologists, and neurosurgeons. In
some countries such as the
Any previous history of hemorrhagic stroke, ischemic stroke within 3 months. History of stroke, dementia, or central nervous system damage within 1 year Head trauma within 3 weeks or brain surgery within 6 months Known intracranial neoplasm Suspected aortic dissection Internal bleeding within 6 weeks Active bleeding or known bleeding disorder Traumatic cardiopulmonary resuscitation within 3 weeks
Oral anticoagulant therapy Acute pancreatitis Pregnancy or within 1 week postpartum Active peptic ulceration Transient ischemic attack within 6 months Dementia Infective endocarditis Active cavitating pulmonary tuberculosis Advanced liver disease Intracardiac thrombi Uncontrolled hypertension (systolic blood pressure >180 mm Hg, diastolic blood pressure >110 mm Hg) Puncture of noncompressible blood vessel within 2 weeks Previous streptokinase therapy
Major surgery, trauma, or bleeding within 2 weeks Stroke Absolute contraindications:
Uncertainty about time of stroke onset (e.g. patients awakening from sleep). Coma or severe obtundation with fixed eye deviation and complete hemiplegia. Hypertension: systolic blood pressure ≥ 185mmHg; or diastolic blood pressure >110mmHg on repeated measures prior to study. (if reversed, patient can be treated) Clinical presentation suggestive of subarachnoid haemorrhage even if the CT scan is normal. Presumed septic embolus. Patient having received a heparin medication within the last 48 hours and has an elevated Activated Prothrombin Time (APTT) or has a known hereditary or acquired haemorrhagic diathesis INR >1.7 Known advanced liver disease, advanced right heart failure, or anticoagulation, and INR > 1.5 (no need to wait for INR result in the absence of the former three conditions). Known platelet count <100,000 uL. Serum glucose is < 2.8 mmol/l or >22.0 mmol/l.
Severe neurological impairment with NIHSS score >22.
Age >80 years.
CT evidence of extensive middle cerebral artery (MCA) territory
infarction (sulcal effacement or blurring of grey-white junction in
greater than 1/3 of MCA territory).
Hemorrhagic stroke is a rare but serious complication of thrombolytic
therapy. If a patient has had thrombolysis before, an allergy against
the thrombolytic drug may have developed (especially after
streptokinase). If the symptoms are mild, the infusion is stopped and
the patient is commenced on an antihistamine before infusion is
Research In people who receive thrombolytic therapy delivered through a catheter, there is a risk of hemorrhage as a side effect. Scientists have studied whether measuring fibrinogen in blood can be used as a biomarker to predict hemorrhage. As of 2017 it was not known if this works or not. See also
TIMI – thrombolysis in myocardial infarction
^ "Indications for fibrinolytic therapy in suspected acute myocardial
infarction: collaborative overview of early mortality and major
morbidity results from all randomised trials of more than 1000
patients. Fibrinolytic Therapy Trialists' (FTT) Collaborative Group".
Lancet. 343 (8893): 311–22. 5 February 1994.
doi:10.1016/s0140-6736(94)91161-4. PMID 7905143.
^ Wardlaw JM, Murray V, Berge E, Del Zoppo GJ (2014). "Thrombolysis
for acute ischaemic stroke". Cochrane Database Syst Rev (7): CD000213.
doi:10.1002/14651858.CD000213.pub3. PMC 4153726 .
^ Wechsler LR (2011). "
v t e
Proteins involved in coagulation
vWF platelet membrane glycoproteins: Ib (A B IX) IIb/IIIa (IIb IIIa) VI
HMWK/Bradykinin Prekallikrein/Kallikrein XII "Hageman" XI IX VIII
III "Tissue factor" VII
Plasmin tPA/urokinase PAI-1/2 α2-AP α2-macrog