Percutaneous Coronary Intervention (PCI)

OVERVIEW

• Percutaneous coronary intervention (PCI) is the preferred emergency reperfusion strategy in most cases of ST elevation myocardial infarction (STEMI)
• PCI is also performed following non-ST elevation ACS (NSTEACS), though the timing depends on how ‘at risk’ the patient is

ACTIVATION OF THE CATH LAB

• Current guidelines recommend that a specific hospital CODE call (e.g. “CODE STEMI”) should be activated
• This alerts all personnel required to perform coronary angiography and PCI in a timely manner
• Personnel involved should include:
  • interventional cardiologist
  • Emergency Department staff
  • Angiography suite staff
  • Coronary Care Unit

INDICATIONS FOR PCI

STEACS

• All cases suitable for intervention are done emergently.
• PCI is the preferred reperfusion strategy providing:
  • can be achieved within 90min of arrival to the ED
  • symptom onset within the previous 12h

NSTEACS

• Time frames vary according to the level of risk.
  • Very High Risk NSTEACS: within 2h
  • High Risk NSTEACS: within 24h
  • Intermediate Risk NSTEACS: within 72h
  • Low Risk NSTEACS (no recurrent symptoms and no risk criteria): selective invasive strategy guided by provocative testing for inducible ischaemia

RISK STRATIFICATION OF PATIENTS WITH CONFIRMED ACS

Very High Risk

• Haemodynamic instability:
  • Heart failure/ cardiogenic shock
  • Mechanical complications of myocardial infarction
• Life-threatening arrhythmias or cardiac arrest
• Recurrent or ongoing ischaemia (e.g. chest pain refractory to medical treatment) or recurrent dynamic ST segment and/or T wave changes, particularly with:
  • Intermittent ST segment elevation
  • de Winter T wave changes
  • Wellens syndrome (or LMCA syndrome)
  • Widespread ST elevation in two or more coronary territories

High Risk

• Rise and/or fall in troponin level consistent with myocardial infarction
• Dynamic episode of ST segment and/or T wave changes with or without symptoms
• GRACE score >140

Intermediate Risk

• Diabetes mellitus
• Renal insufficiency (glomerular filtration rate < 60mL/min/1.73m2)
• Left ventricular ejection fraction ≤ 40 %
• Prior revascularization:
  • Percutaneous coronary intervention
  • Coronary artery bypass grafting
• GRACE score >109 and <140

Low Risk

• Patients with NSTEACS who have both of:
  • no recurrent symptoms
  • no risk criteria (as listed above)

MANAGEMENT

Initial management in the ED

• Call Code STEMI and facilitate expeditious transfer to the Cath Lab
•  Resuscitation
  • attend to ABCs
  • address immediate life threats
• Control of pain
  • nitrates/ morphine as indicated
• Aspirin 300mg po
• Ticagrelor 180 mg (loading dose)
  • assess bleeding risk before administration
  • avoid if emergency coronary artery bypass grafting is likely
• Anticoagulation therapy
  • initial 5,000 unit heparin IV bolus (preferred to subcutaneous fractionated heparins (e.g. enoxaparin) to reduce risk of bleeding complications during PCI)
  • if enoxaparin has already been given, or there prior thrombolysis gas been performed, PCI can still be performed
• Glycoprotein IIb/IIIa inhibitor therapy
  • also recommended in patients who are to receive urgent PCI.
  • options include:
    • Integrilin (eptifibatide)
    • Reopro (Abciximab)
    • Aggrastat (Tirofiban)
• Bivalirudin (direct thrombin inhibitor)
  • can be considered as an alternative to heparin and GP IIb/IIIa inhibitors for patients with STEMI undergoing primary PCI

Other considerations

• If cardiac arrest occurs, consider transfer to the cath lab with mechanical CPR in progress
• ECMO-CPR (if available) may be performed prior to, or following, transfer to the cath lab depending on logistics
• Consider with-holding glycoprotein IIb/IIIa inhibitor therapy if mechanical CPR and/or ECMO-CPR is required

Disposition post-PCI

•  all patients should then be admitted to CCU or ICU
• if complications may arise during PCI, transfer to a cardiothoracic surgery center may be required

ASSESSMENT OF BLEEDING RISK

• The routine use of a validated risk stratification tool, such as the CRUSADE Score, for bleeding events assists with individual patient clinical decision making
• The CRUSADE Score is available on MDCALC [CRUSADE Score for Post-MI Bleeding Risk]
• The CRUSADE score risk stratifies patients for bleeding complications according to 8 parameters:
  • Heart Rate
  • Systolic Blood Pressure
  • Hematocrit
  • Creatinine Clearance
  • Sex
  • Signs of CHF at Presentation
  • History of Vascular Disease
  • History of Diabetes Mellitus

References and Links

• Chew DP, Scott IA, Cullen L, et al. National Heart Foundation of Australia and Cardiac Society of Australia and New Zealand: Australian clinical guidelines for the management of acute coronary syndromes 2016. The Medical journal of Australia. 205(3):128-33. 2016. [pubmed]
• Chew DP, Scott IA, Cullen L, et al. National Heart Foundation of Australia & Cardiac Society of Australia and New Zealand: Australian Clinical Guidelines for the Management of Acute Coronary Syndromes 2016. Heart, lung & circulation. 25(9):895-951. 2016. [pubmed] [free full text]