Week 7 – Lecture C – Postcardiotomy shock: Peripheral versus Central VA ECMO cannulation. (Ahmed Hegazy)

Incidence & Outcomes

  • Rising incidence: ↑178% (2004–2014) due to aging, comorbid population.
  • Most frequent ECLS indication in USA.
  • Survival poor: ~25% hospital discharge, 18% at 6 months.
  • High complications: bleeding, renal failure, re-operations, limb ischemia.

Causes & Risk Factors

  • Causes: myocardial stunning, inflammatory response, ischemia–reperfusion injury, inadequate protection.
  • Patient profile: elderly, comorbidities, on multiple medications, often with sepsis or ischemia.
  • Death on ECMO: mainly multiorgan failure, persistent heart failure, bleeding.
  • Death post-weaning: persistent heart failure, multiorgan failure, sepsis.

Key Factors Affecting Survival

1. Patient Factors

  • Age: Mortality very high >70 years (76%).
  • Obesity: No association with mortality (not a contraindication).

2. Timing of ECMO Initiation

  • Intra-op initiation: Better early survival vs post-op.
  • Post-op initiation: Worse survival, higher complications.
  • Ward initiation: Very poor outcomes (~15%).
  • High lactate (>10 mmol/L) at initiation → worse survival.
  • Actionable: Earlier initiation improves outcomes.

3. LV Unloading

  • Rationale: VA ECMO ↑ afterload, may hinder recovery.
  • Non-invasive: reduce ECMO flow, adjust ventilation, diuretics, vasodilators.
  • Invasive: balloon pump, Impella, direct LV/LA/PA drainage.
  • Evidence: Balloon pump + ECMO → improved survival, fewer complications.
  • Weaning strategy: Remove ECMO first, keep balloon pump.

4. Bleeding Control

  • Bleeding common early (days 1–3); thrombosis later.
  • Both ↑ mortality.
  • Dutch strategy: full protamine, meticulous hemostasis, sternum closure, no heparin 24–72h, point-of-care testing → reduced bleeding, trend to better survival.

5. Cannulation Approach

  • Central ECMO: higher mortality, stroke risk, reoperation needs.
  • Peripheral ECMO: better survival; femoral preferred (lowest stroke risk), though limb ischemia risk ↑.
  • Subclavian: avoids limb ischemia, allows mobilization, but higher stroke risk.

6. ECMO Duration

  • <3 days: best survival.
  • 3–7 days: reduced survival.
  • 7 days: poor outcomes → exit strategy essential.

Conclusion

  • Best outcomes: Age <70, early ECMO initiation, early LV unloading (balloon pump), vigilant bleeding control, preference for peripheral cannulation, and limiting central ECMO runs <7 days.
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