What is the role of Extracorporeal Membrane Oxygenation (ECMO) and Intra-Aortic Balloon Pump (IABP) in managing cardiogenic shock during complex Percutaneous Coronary Intervention (PCI)?

Role of ECMO and IABP in Cardiogenic Shock During Complex PCI

In patients with acute myocardial infarction and cardiogenic shock, the routine use of intra-aortic balloon pump (IABP) or venoarterial extracorporeal membrane oxygenation (VA-ECMO) is not recommended due to lack of survival benefit, while microaxial intravascular flow pumps may be reasonable in selected patients with severe or refractory cardiogenic shock. 1

Mechanical Circulatory Support Options in Cardiogenic Shock

Current Guideline Recommendations

The 2025 ACC/AHA/ACEP/NAEMSP/SCAI guidelines provide clear direction on mechanical circulatory support (MCS) in cardiogenic shock during PCI:

1. Microaxial intravascular flow pumps (e.g., Impella):

   • Class 2a, Level B-R recommendation for selected patients with STEMI and severe/refractory cardiogenic shock 1
   • Reasonable to reduce mortality in carefully selected patients

2. IABP and VA-ECMO:

   • Class 3 (No Benefit), Level B-R recommendation 1
   • Not recommended for routine use due to lack of demonstrated survival benefit
   • Despite physiological benefits (IABP increases coronary perfusion, decreases myocardial oxygen demand), clinical outcomes do not show mortality benefit

3. Short-term MCS devices:

   • Class 2a, Level B-NR recommendation for patients with mechanical complications of ACS 1
   • Reasonable for hemodynamic stabilization as a bridge to surgery

ECMO in Cardiogenic Shock During PCI

While routine use of VA-ECMO is not recommended, the 2015 AHA guidelines suggest:

• ECPR (extracorporeal CPR) may be reasonable as a rescue treatment when initial therapy is failing for cardiac arrest during PCI (Class IIb, LOE C-LD) 1
• The combination of ECPR and IABP has been associated with increased survival compared to IABP alone in some observational studies 1
• Rapid initiation of ECPR or cardiopulmonary bypass is associated with good outcomes in patients with hemodynamic collapse and cardiac arrest in the catheterization lab 1

Device Selection Algorithm

Selection of appropriate mechanical support should be based on:

1. Predominant failure pattern:

   • Left ventricular failure: Consider Impella devices
   • Right ventricular failure: Consider Impella RP
   • Biventricular failure: Consider VA-ECMO with LV venting 2

2. Clinical scenario:

   • Cardiac arrest during PCI: Consider ECPR as rescue therapy 1
   • Mechanical complications: Short-term MCS devices for stabilization 1
   • Severe/refractory shock: Consider microaxial flow pumps 1

Important Considerations and Pitfalls

Timing of Intervention

• For every 10-minute delay in primary PCI after 60 minutes from first medical contact, there are 3-4 additional deaths per 100 patients 1
• Observational studies often implement ECPR 20-30 minutes after cardiac arrest 1
• Early intervention is critical - mortality exceeds 80% with delays beyond 6 hours 1

Culprit-Only vs. Multivessel PCI

• In patients with STEMI complicated by cardiogenic shock and multivessel disease, a strategy of culprit-vessel-only PCI is recommended 1
• The CULPRIT-SHOCK trial showed higher rates of death or need for renal replacement therapy with multivessel PCI compared to culprit-only PCI 1

Institutional Considerations

• Institutional guidelines should include selection criteria for mechanical support devices 1
• These devices should be used as a bridge to recovery, surgery, transplant, or other device 1
• Rapid transfer to a tertiary care center with 24/7 cardiac catheterization and ICU capabilities is recommended 2

Evidence Gaps and Controversies

The evidence supporting mechanical support in cardiogenic shock has limitations:

• Meta-analyses of cohort studies showed that IABP was associated with decreased mortality when used with thrombolysis, but increased mortality when used with primary PCI 1
• Small studies have shown promising results with awake ECMO as a bridge to recovery 3
• ECMO-assisted PCI may improve 30-day and 1-year survival rates in profound cardiogenic shock 4

Conclusion

When managing cardiogenic shock during complex PCI:

1. Consider microaxial intravascular flow pumps in selected patients with severe/refractory shock
2. Avoid routine use of IABP or VA-ECMO
3. Consider ECPR as rescue therapy for cardiac arrest during PCI
4. Focus on rapid revascularization of the culprit vessel
5. Transfer to a tertiary center with mechanical support capabilities when appropriate