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.