What are the contraindications for fibrinolysis (thrombolytic) therapy in a patient with acute myocardial infarction (AMI)?

Contraindications of Fibrinolytic Therapy

Fibrinolytic therapy is absolutely contraindicated in patients with any prior intracranial hemorrhage at any time, suspected aortic dissection, active bleeding, ischemic stroke within 3-6 months, significant head/facial trauma within 3 months, or known structural cerebral vascular lesions. 1, 2, 3

Absolute Contraindications

Neurological Contraindications

• Any prior intracranial hemorrhage at any time in the patient's life is an absolute contraindication, regardless of how remote the event 1, 2, 3
• Ischemic stroke within 3-6 months (ACCF/AHA uses 3 months; ESC uses 6 months as the cutoff), with the exception of acute ischemic stroke within 4.5 hours of onset 1, 2, 3
• Known structural cerebral vascular lesions including arteriovenous malformations or aneurysms 1, 2, 3
• Known malignant intracranial neoplasm (primary or metastatic) 1, 2, 3
• Intracranial or intraspinal surgery within 2 months 1, 3
• Significant closed-head or facial trauma within 3 months 1, 2, 3

Cardiovascular Contraindications

• Suspected or confirmed aortic dissection due to catastrophic risk of rupture 1, 2, 3

Bleeding-Related Contraindications

• Active bleeding or bleeding diathesis (excluding menstruation) 1, 2, 3
• Gastrointestinal bleeding within the past month 1, 2
• Major trauma or major surgery within the past 3 weeks 1, 2, 3
• Non-compressible punctures in the past 24 hours (e.g., liver biopsy, lumbar puncture) 1, 2

Blood Pressure Contraindications

• Severe uncontrolled hypertension unresponsive to emergency therapy (systolic BP ≥180 mmHg or diastolic BP ≥110 mmHg) is considered an absolute contraindication by ACCF/AHA, though ESC lists this as relative 1

Agent-Specific Contraindications

• For streptokinase/anistreplase: prior treatment within the previous 5-6 months or prior allergic reaction to these agents 1, 2, 3

Relative Contraindications

Neurological Relative Contraindications

• Transient ischemic attack within the preceding 6 months requires careful risk-benefit evaluation 1, 2, 3
• History of prior ischemic stroke >3-6 months ago 1, 2, 3
• Dementia 1, 3
• Known intracranial pathology not covered in absolute contraindications 1, 3

Blood Pressure Relative Contraindications

• Significant hypertension on presentation (SBP >180 mmHg or DBP >110 mmHg) that responds to therapy 1, 2, 3
• History of chronic, severe, poorly controlled hypertension 1, 2, 3

Procedural/Trauma Relative Contraindications

• Traumatic or prolonged CPR (≥10 minutes) 1, 2, 3
• Major surgery within 3 weeks 1, 2, 3
• Recent internal bleeding (within 2-4 weeks) 1, 2
• Non-compressible vascular punctures 1, 2

Other Medical Conditions

• Pregnancy or within 1 week postpartum 1, 2, 3
• Active peptic ulcer 1, 2, 3
• Current use of oral anticoagulants (higher INR = higher bleeding risk) 1, 2, 3
• Advanced liver disease 1, 2
• Infective endocarditis 1, 2

Critical Clinical Decision Points

When to Choose PCI Over Fibrinolysis

• STEMI patients at substantial (≥4%) risk of intracranial hemorrhage should be treated with PCI rather than fibrinolytic therapy 1, 3
• Primary PCI is strongly preferred when absolute contraindications exist 3, 4
• Cardiogenic shock: fibrinolysis is not effective; primary PCI is preferred 2

Time-Dependent Considerations

• Fibrinolysis should not be administered after 24 hours of symptom onset (Class III) 1, 2
• Between 12-24 hours, fibrinolysis is generally not recommended unless there is persistent ischemic pain with continued ST elevation (Class IIb) 1, 2
• Benefit is maximal within the first 6 hours: absolute mortality reduction of ~30 per 1000 in 0-6 hours, ~20 per 1000 in 7-12 hours 2, 5

Risk Stratification for Intracranial Hemorrhage

The risk of intracranial hemorrhage increases with the following factors 1, 2:

• Age ≥65-75 years (most important baseline variable predicting stroke)
• Low body weight (≤70 kg)
• Female sex
• Hypertension on presentation (≥180/110 mmHg)
• Use of tissue plasminogen activator (rtPA)

The number of risk factors can estimate stroke frequency: 0.25% with no risk factors to 2.5% with 3 risk factors 1

Special Populations

• Patients aged ≥75 years have higher risk of hemorrhagic stroke but similar absolute mortality benefit to younger patients, though the net benefit is reduced 1, 2
• Successful brief resuscitation does not contraindicate fibrinolysis, but prolonged or traumatic resuscitation increases bleeding risk 2

Common Pitfalls to Avoid

• Do not dismiss any history of intracranial hemorrhage as "too remote" – this is an absolute contraindication regardless of timing 2, 3
• Do not confuse relative with absolute contraindications – relative contraindications require careful risk-benefit assessment but are not absolute prohibitions 1, 2
• Do not overlook recent procedures – non-compressible punctures within 24 hours are absolute contraindications 1, 2
• Do not underestimate bleeding risk in elderly, low-weight, or female patients – these populations have significantly higher rates of intracranial hemorrhage 1, 2, 6