STEMI criteria

• clinical symptoms consistent with ACS (generally of ≥ 20 minutes duration) with persistent (> 20 minutes) ECG features in ≥ 2 contiguous leads of:
  • 2.5 mm (i.e ≥ 2.5 small squares) ST elevation in leads V2-3 in men under 40 years, or ≥ 2.0 mm (i.e ≥ 2 small squares) ST elevation in leads V2-3 in men over 40 years
  • 1.5 mm ST elevation in V2-3 in women
  • 1 mm ST elevation in other leads
  • new LBBB (LBBB should be considered new unless there is evidence otherwise)

Once a STEMI has been confirmed the first step is to immediately assess eligibility for coronary reperfusion therapy. There are two types of coronary reperfusion therapy:

• percutaneous coronary intervention
  • should be offered if the presentation is within 12 hours of the onset of symptoms AND PCI can be delivered within 120 minutes of the time when fibrinolysis could have been given (i.e. consider fibrinolysis if there is a significant delay in being able to provide PCI)
  • if patients present after 12 hours and still have evidence of ongoing ischaemia then PCI should still be considered
  • drug-eluting stents are now used. Previously 'bare-metal' stents were sometimes used but have higher rates of restenosis
  • radial access is preferred to femoral access
• fibrinolysis
  • should be offered within 12 hours of the onset of symptoms if primary PCI cannot be delivered within 120 minutes of the time when fibrinolysis could have been given
  • a practical example may be a patient who presents with a STEMI to a small district general hospital (DGH) that does not have facilities for PCI. If they cannot be transferred to a larger hospital for PCI within 120 minutes then fibrinolysis should be given. If the patient's ECG taken 90 minutes after fibrinolysis failed to show resolution of the ST elevation then they would then require transfer for PCI

If patients are eligible this should be offered as soon as possible.

Percutaneous coronary intervention for patients with STEMI

Further antiplatelet prior to PCI

• this is termed 'dual antiplatelet therapy', i.e. aspirin + another drug
• if the patient is not taking an oral anticoagulant: prasugrel
• if taking an oral anticoagulant: clopidogrel

Drug therapy during PCI

• patients undergoing PCI with radial access:
  • unfractionated heparin with bailout glycoprotein IIb/IIIa inhibitor (GPI) - this is the action of using a GPI during the procedure when it was not intended from the outset, e.g. because of worsening or persistent thrombus
• patients undergoing PCI with femoral access:
  • bivalirudin with bailout GPI

Other procedures during PCI

• thrombus aspiration, but not mechanical thrombus extraction, should be considered
• complete revascularisation should be considered for patients with multivessel coronary artery disease without cardiogenic shock