What is the target mean arterial pressure (MAP) for post-coronary artery bypass graft (CABG) patients in cardiogenic shock?

Blood Pressure Target for Cardiogenic Shock in Post-CABG Patients

Target a mean arterial pressure (MAP) of at least 65 mmHg, with strong consideration for higher targets (≥70 mmHg) in post-CABG cardiogenic shock patients, as higher MAP is associated with improved mortality and clinical outcomes in this population.

Primary MAP Target

• The minimum MAP target should be ≥65 mmHg using the lowest necessary dose of vasopressor therapy to maintain adequate organ perfusion 1
• This 65 mmHg threshold represents the established baseline for ensuring tissue perfusion pressure in shock states 2
• However, this target should be viewed as a floor rather than an optimal goal in cardiogenic shock 1

Evidence for Higher MAP Targets in Cardiogenic Shock

Recent evidence strongly suggests targeting MAP ≥70 mmHg in cardiogenic shock improves outcomes:

• In patients with cardiogenic shock treated with inotropes, achieving an average MAP ≥70 mmHg was associated with significantly better outcomes compared to MAP <70 mmHg 3
• The higher MAP group (≥70 mmHg) demonstrated:
  • 43% reduction in the composite primary outcome (adjusted RR 0.70,95% CI 0.53-0.92) 3
  • 44% reduction in all-cause mortality (28.9% vs 57.8%, adjusted RR 0.56,95% CI 0.40-0.79) 3

Post-CABG Specific Considerations

Emergency CABG in cardiogenic shock requires aggressive hemodynamic optimization:

• Emergency CABG is recommended for cardiogenic shock patients when coronary anatomy is suitable, irrespective of time interval from MI to shock onset 1
• Management should target optimizing determinants of coronary arterial perfusion, including mean arterial pressure, to reduce perioperative myocardial ischemia and infarction 1
• During on-pump CABG procedures, maintaining MAP >60 mmHg is recommended as an absolute minimum 4

Vasopressor Strategy

Norepinephrine should be the first-line vasopressor:

• Norepinephrine is favored as first-line therapy to achieve MAP targets in cardiogenic shock 1
• Use the minimum necessary vasopressor dose to maintain the target MAP 1
• Alternative agents may be considered in specific circumstances:
  • Dopamine or epinephrine for unstable bradycardia requiring chronotropic support 1
  • Phenylephrine or vasopressin for dynamic LV outflow tract obstruction 1
  • Vasopressin for refractory hypoxemia or acidosis where catecholamine efficacy may be attenuated 1

Important Caveats

Caution is required with progressive escalation:

• While higher MAP targets appear beneficial, excessive vasopressor escalation carries risks 1
• Targeting MAP of 85 mmHg (compared to 65 mmHg) in septic shock resulted in significantly higher risk of arrhythmias, though this data is from septic rather than cardiogenic shock 1
• Continuous reassessment of clinical perfusion status is mandatory, as MAP alone does not guarantee adequate tissue perfusion 1

Monitoring Beyond MAP

Additional hemodynamic parameters should guide management:

• Document LV end-diastolic pressure before contrast administration, as elevated pressures are associated with increased mortality 1
• Monitor for signs of adequate organ perfusion beyond MAP alone 1
• Consider early mechanical ventilation if respiratory failure develops, as worsening hypoxemia and acidosis increase susceptibility to ventricular fibrillation and may increase mortality risk during revascularization 1

Clinical Algorithm

1. Initial stabilization: Achieve MAP ≥65 mmHg with norepinephrine as first-line 1
2. Target optimization: Aim for MAP ≥70 mmHg based on cardiogenic shock-specific outcome data 3
3. Continuous assessment: Monitor end-organ perfusion markers, not just MAP 1
4. Vasopressor titration: Use minimum necessary doses while achieving targets 1
5. Consider mechanical support: If vasopressor requirements escalate excessively or hemodynamic instability persists despite initial measures 1