What is the optimal timing for coronary artery bypass grafting (CABG) following acute coronary syndrome (ACS)?

Optimal Timing of CABG Following Acute Coronary Syndrome

The optimal timing for coronary artery bypass grafting (CABG) following acute coronary syndrome (ACS) should be based on patient risk stratification, with immediate intervention (<2 hours) for very high-risk patients, early intervention (<24 hours) for high-risk patients, and delayed intervention (48-72 hours) for stable intermediate or low-risk patients. 1

Risk Stratification and Timing Recommendations

Very High-Risk Patients (Immediate Invasive Strategy <2 hours)

• Immediate CABG is recommended for patients with at least one of these criteria: hemodynamic instability or cardiogenic shock, recurrent/ongoing chest pain refractory to medical treatment, life-threatening arrhythmias, mechanical complications of MI, acute heart failure with refractory angina, or recurrent dynamic ST/T-wave changes 1
• In patients with cardiogenic shock, emergency revascularization (including CABG when appropriate) significantly reduces mortality at 6 months compared to medical therapy alone 1
• For patients with STEMI who are hemodynamically unstable with anatomy not amenable to PCI, or if PCI is unsuccessful, emergency CABG can be performed if a large area of myocardium is at risk 1

High-Risk Patients (Early Invasive Strategy <24 hours)

• Early CABG (within 24 hours) is recommended for patients with high-risk features including: rise or fall in cardiac troponin compatible with MI, dynamic ST or T-wave changes, or GRACE score >140 1
• The TIMACS and VERDICT trials demonstrated a lower rate of cardiovascular events in high-risk patients randomized to early angiography and appropriate revascularization 1

Intermediate/Low-Risk Patients (Delayed Invasive Strategy 48-72 hours)

• For intermediate or low-risk patients who are hemodynamically stable, a delayed invasive strategy within 48-72 hours is acceptable 1
• Randomized trials have not demonstrated differences in rates of death and MI between early (<24 hours) and delayed (48-72 hours) invasive approaches in non-selected NSTEMI populations 1

Antiplatelet Management Before CABG

• For elective CABG, clopidogrel and ticagrelor should be discontinued at least 5 days before surgery, and prasugrel for at least 7 days before surgery to minimize bleeding risk 1, 2
• For urgent CABG, clopidogrel and ticagrelor should be discontinued for at least 24 hours to reduce major bleeding complications 1, 2
• When CABG is performed 1-4 days after clopidogrel discontinuation, the risk of life-threatening bleeding is not significantly increased, but blood transfusion requirements are likely higher 1, 2

Special Considerations

Multivessel Disease

• In patients with multivessel disease, the decision between PCI and CABG should be individualized through consultation with the Heart Team 1
• A sequential approach (treating the culprit lesion with PCI followed by elective CABG with proof of ischemia for non-culprit lesions) may be advantageous in selected patients 1

Outcomes

• Despite being performed in higher-risk patients, early CABG for ACS is associated with very low in-hospital mortality compared to medical management alone 3
• The CRUSADE registry showed median time to CABG was 69.9 hours for weekday admissions and 86.3 hours for weekend admissions, with no significant difference in mortality outcomes 1
• Studies from Japan suggest that when ACS patients are stabilized with medical therapies including IABP, urgent rather than emergency CABG allows for more complete revascularization with comparable long-term outcomes 4, 5

Common Pitfalls and Caveats

• Delaying CABG unnecessarily in very high-risk patients can lead to increased mortality, particularly in those with cardiogenic shock 1
• Performing CABG too early in patients on dual antiplatelet therapy increases bleeding risk; balance this against the risk of delaying surgery 1, 2
• For patients with failed PCI who have ongoing ischemia or hemodynamic compromise, emergency CABG is associated with reduced mortality despite increased procedural risk 1
• Advanced age (>70 years) and severely reduced left ventricular function (LVEF <30%) are independent predictors of early mortality following CABG after ACS 6

By following this risk-stratified approach to the timing of CABG after ACS, clinicians can optimize outcomes by balancing the risks of delaying revascularization against the risks of operating on patients who may benefit from medical stabilization.