In an adult with ST‑elevation myocardial infarction, how should we choose between primary percutaneous coronary intervention and fibrinolytic therapy based on anticipated door‑to‑balloon time and any contraindications?

Choosing Between Primary PCI and Fibrinolytic Therapy in STEMI Based on Timing

Primary PCI is the preferred reperfusion strategy when first-medical-contact-to-device time can be achieved within 90 minutes at a PCI-capable hospital or within 120 minutes when transfer from a non-PCI-capable hospital is required; otherwise, fibrinolytic therapy should be administered within 30 minutes of hospital arrival if no contraindications exist. 1

Time-Based Decision Algorithm

At a PCI-Capable Hospital

• Perform primary PCI if first-medical-contact-to-device time ≤90 minutes as the system goal 1
• This represents the preferred reperfusion method when timely PCI can be delivered by experienced operators 1
• Every effort should be made to minimize door-to-balloon time, as delays correlate with increased mortality in a continuous, nonlinear fashion 1

At a Non-PCI-Capable Hospital

If anticipated first-medical-contact-to-device time at a PCI-capable hospital ≤120 minutes:

• Immediately transfer the patient for primary PCI 1
• The door-in-door-out time at the referring facility should be ≤30 minutes 1
• This transfer strategy is the recommended approach even with moderate delays 1

If anticipated first-medical-contact-to-device time at a PCI-capable hospital >120 minutes:

• Administer fibrinolytic therapy immediately if no contraindications exist 1
• The door-to-needle time must be ≤30 minutes from hospital arrival 1
• All patients receiving fibrinolysis must be transferred promptly to a PCI-capable center after drug administration 2

Absolute Indications for Primary PCI Regardless of Time Delay

The following clinical scenarios mandate primary PCI irrespective of anticipated time delays: 1

• Cardiogenic shock or acute severe heart failure – these patients should undergo emergency PCI as soon as possible, even if symptom onset exceeds 12 hours 1
• Contraindications to fibrinolytic therapy – primary PCI should be performed regardless of time delay from first medical contact when fibrinolysis cannot be safely administered 1
• Failed fibrinolysis (rescue PCI) – defined as <50% ST-segment resolution at 60-90 minutes, hemodynamic instability, or worsening ischemia 2

Symptom Duration Considerations

Presentation Within 12 Hours of Symptom Onset

• Reperfusion therapy (either PCI or fibrinolysis) should be administered to all eligible patients 1
• The choice between modalities depends strictly on the time metrics outlined above 1
• Fibrinolytic benefit is greatest when administered within the first 2 hours after symptom onset, with absolute mortality reductions of 3% for patients presenting within 0-6 hours 1

Presentation 12-24 Hours After Symptom Onset

• Primary PCI is reasonable if clinical and/or ECG evidence of ongoing ischemia exists (persistent chest pain, ST-segment elevation, or hemodynamic instability) 1
• Fibrinolytic therapy may be considered in the absence of contraindications when PCI is unavailable and there is ongoing ischemia with a large area of myocardium at risk or hemodynamic instability 1
• Asymptomatic, hemodynamically stable patients with completed infarction should receive medical therapy rather than routine PCI 3

Presentation >24 Hours After Symptom Onset

• Primary PCI should NOT be performed in stable, asymptomatic patients with a totally occluded infarct artery – this provides no benefit and is a Class III (No Benefit) recommendation 1, 3
• Emergency PCI remains indicated for cardiogenic shock or severe heart failure regardless of elapsed time 1, 3

Post-Fibrinolysis Management

All patients who receive fibrinolytic therapy require specific post-treatment protocols: 2

• Coronary angiography should be performed 2-24 hours after successful fibrinolysis, but NOT within the first 3 hours unless rescue PCI criteria are met 2, 4
• Immediate rescue PCI is indicated for:
  • <50% ST-segment resolution at 60-90 minutes post-fibrinolysis 2
  • Hemodynamic or electrical instability at any time 2
  • Worsening ischemia or evidence of re-occlusion 2
  • Development of cardiogenic shock or acute heart failure 2

Critical Contraindications to Fibrinolytic Therapy

Fibrinolytic therapy is absolutely contraindicated in the following situations: 2

• Prior intracranial hemorrhage (any time) 2
• Ischemic stroke within the past 3 months 2
• Known intracranial neoplasm, arteriovenous malformation, or aneurysm 2
• Active internal bleeding 2
• Intracranial or intraspinal surgery/trauma within the past 2 months 2
• Bleeding diathesis (thrombocytopenia, coagulopathy) 2
• Severe uncontrolled hypertension (SBP >180 mmHg or DBP >110 mmHg) 2

Fibrinolytic therapy should NOT be administered to patients with ST-segment depression except when true posterior (inferobasal) MI is suspected or when associated with ST elevation in lead aVR 1, 2

Common Pitfalls and How to Avoid Them

Do not delay fibrinolysis when primary PCI cannot be achieved within guideline-recommended times – each 30-minute delay reduces therapeutic efficacy, and the survival benefit is greatest when fibrinolytics are administered within the first 2 hours 1, 2

Do not perform routine angiography within 3 hours of fibrinolytic administration unless rescue PCI criteria are met (failed reperfusion, hemodynamic instability, or worsening ischemia) 2, 4

Do not substitute fibrinolysis for timely primary PCI when PCI can be achieved within the 90-minute (direct presentation) or 120-minute (transfer) windows – primary PCI remains superior when delivered in a timely fashion 1, 5, 6

Do not perform PCI on a totally occluded infarct artery >24 hours after STEMI in hemodynamically stable, asymptomatic patients – evidence shows no benefit and this is a Class III (No Benefit) recommendation 1, 3

Do not administer fibrinolytics to NSTEMI patients – this provides no benefit and may cause harm 2

Evidence Quality and Nuances

The guidelines are based on Class I, Level A and B evidence from multiple large randomized trials demonstrating that primary PCI is superior to fibrinolytic therapy when performed in a timely manner 1. However, the critical insight is that time to reperfusion is more important than the choice of reperfusion modality 1. The 2017 AHA/ACC and 2013 ACCF/AHA guidelines consistently emphasize that unavoidable delays to primary PCI should prompt immediate fibrinolytic administration rather than accepting prolonged ischemic time 1.

Recent research supports a pharmaco-invasive strategy (fibrinolysis followed by routine angiography within 3-24 hours) as non-inferior to primary PCI in patients with long transfer delays (>60 minutes), particularly when fibrinolysis is administered early after symptom onset 5, 7. This approach combines the time advantage of immediate pharmacologic reperfusion with the mechanical benefits of subsequent PCI 5, 8, 7.