What is the initial approach for treating acute coronary syndrome, including the role of surgical revascularization via Coronary Artery Bypass Grafting (CABG) and Percutaneous Coronary Intervention (PCI)?

Initial Approach and Revascularization Strategies for Acute Coronary Syndrome

The initial management of acute coronary syndrome (ACS) should be risk-stratified, with an early invasive strategy recommended for high-risk patients, while PCI is the preferred revascularization method for most ACS patients, with CABG reserved for complex coronary anatomy or left main disease. 1

Risk Stratification and Initial Management

• All patients with suspected ACS should undergo immediate risk stratification based on clinical presentation, ECG findings, and cardiac biomarkers to determine the appropriate management strategy 1

• Patients should be categorized into ST-elevation myocardial infarction (STEMI) or non-ST-elevation ACS (NSTE-ACS), which includes unstable angina and non-ST-elevation myocardial infarction (NSTEMI) 2

• The TIMI risk score, which includes 7 independent prognostic variables, is recommended to assess the risk of major adverse cardiac events and guide treatment decisions 1

Timing of Invasive Strategy for NSTE-ACS

An immediate invasive strategy (<2 hours) is recommended for NSTE-ACS patients with:

• Hemodynamic instability or cardiogenic shock
• Recurrent or refractory chest pain despite medical treatment
• Life-threatening arrhythmias
• Mechanical complications of MI
• Heart failure clearly related to NSTE-ACS
• ST-segment depression >1 mm in ≥6 leads with ST-segment elevation in aVR and/or V1 1

An early invasive strategy (within 24 hours) is recommended for patients with:

• Diagnosis of NSTEMI
• Dynamic or new contiguous ST/T-segment changes suggesting ongoing ischemia
• Transient ST-segment elevation
• GRACE risk score >140 1

Revascularization for STEMI

• Primary PCI is the preferred reperfusion strategy for STEMI patients when performed within 120 minutes of first medical contact 1, 2

• For STEMI patients in shock or who are hemodynamically unstable, immediate revascularization is recommended regardless of timing from symptom onset 1

• CABG is indicated for STEMI patients when PCI is not feasible, which is the only Class 1 indication for CABG in STEMI outside of mechanical complications 1

• Complete revascularization of non-culprit lesions in stabilized STEMI patients with multivessel disease is recommended as a staged PCI procedure (Class 1) or staged CABG (Class 2a) 1

• Performing non-culprit PCI during the same procedure as the infarct-related artery in hemodynamically stable patients carries a Class 2b recommendation 1

• Same-setting non-culprit PCI in patients with cardiogenic shock now carries a Class 3 (harm) recommendation 1

Revascularization for NSTE-ACS

• For high-risk NSTE-ACS patients without contraindications, an early invasive strategy with coronary angiography and revascularization within 24-48 hours is associated with reduced mortality from 6.5% to 4.9% 2

• The decision between PCI and CABG should be based on:

  • Patient's clinical status and comorbidities
  • Disease severity (distribution and angiographic lesion characteristics)
  • SYNTAX score for complex disease 1

• For single-vessel disease, PCI of the culprit lesion is the first choice 1

• For left main or triple-vessel disease, CABG is the recommended procedure, particularly in patients with left ventricular dysfunction 1

• For double-vessel and some triple-vessel coronary disease, either PCI or CABG may be appropriate based on lesion complexity and patient factors 1

Technical Considerations for Revascularization

• Radial access is recommended as the standard approach for coronary angiography unless there are overriding procedural considerations 1

• Drug-eluting stents (DES) are recommended over bare-metal stents for any PCI regardless of clinical presentation, lesion type, planned non-cardiac surgery, anticipated duration of DAPT, or concomitant anticoagulant therapy 1

• In some patients, a staged procedure may be considered, with immediate PCI of the culprit lesion followed by subsequent reassessment for treatment of other lesions 1

Special Considerations

• For patients with coronary dissection during PCI, consider emergency CABG if PCI is not feasible or fails, especially for dissections involving the left main coronary artery 3

• For patients with ACS and heart failure or cardiogenic shock:

  • Emergency coronary angiography is recommended
  • Emergency PCI of the culprit lesion is recommended if coronary anatomy is amenable
  • Emergency CABG is recommended if coronary anatomy is not amenable to PCI 1

• Routine use of intra-aortic balloon pump in patients with cardiogenic shock and no mechanical complications is not recommended 1

Pitfalls and Caveats

• The decision to implement an initial conservative versus invasive strategy should consider physician and patient preference, but high-risk features should prompt early intervention 1

• Delay in revascularization for STEMI patients increases mortality; if PCI cannot be performed within 120 minutes, fibrinolytic therapy should be administered 2

• For patients planned for CABG, clopidogrel should be stopped approximately 5 days before operation to reduce bleeding risk 1

• In patients with an initial diagnosis of ACS but no significant coronary stenosis on angiography, consider alternative diagnoses, but absence of stenosis does not preclude ACS diagnosis 1