What is the management of cardiogenic shock?

Management of Cardiogenic Shock

Immediately revascularize patients with AMI-related cardiogenic shock within 2 hours of presentation, use norepinephrine as first-line vasopressor, and dobutamine as first-line inotrope to restore perfusion while avoiding routine IABP use. 1, 2

Diagnostic Criteria and Initial Assessment

Diagnose cardiogenic shock using clinical and hemodynamic criteria:

• Systolic blood pressure <90 mmHg for 30 minutes or requiring vasopressors/inotropes to maintain SBP >90 mmHg 1
• Evidence of end-organ hypoperfusion with elevated lactate (>2 mmol/L indicates tissue hypoperfusion) 1, 2
• Hemodynamic criteria: cardiac index <1.8 L/min/m² without support and cardiac power output <0.6 W 1

Perform immediate diagnostic workup:

• ECG and Doppler echocardiography to assess ventricular/valvular function, loading conditions, and detect mechanical complications 2
• Invasive arterial line for accurate blood pressure monitoring 2
• Early pulmonary artery catheter placement to identify specific shock phenotype and guide therapy 1, 2
• Laboratory evaluation including cardiac biomarkers, lactate, and organ function tests 2

Immediate Management Algorithm

Step 1: Revascularization (Highest Priority)

For AMI-related cardiogenic shock, perform immediate coronary angiography within 2 hours with intent to revascularize - this is the only intervention proven to reduce mortality in randomized trials. 1, 3

• Culprit-lesion-only PCI is preferred over multivessel revascularization during index procedure (CULPRIT-SHOCK trial showed 45.9% vs 55.4% rate of 30-day death or kidney replacement therapy, relative risk 0.83, P=0.01) 3
• If coronary anatomy unsuitable for PCI or PCI fails, proceed to emergency CABG 2
• For STEMI with anticipated PCI delay >120 minutes, consider immediate fibrinolysis and transfer to PCI center 2

Step 2: Hemodynamic Support

Initial fluid management:

• Perform fluid challenge (saline or ringer lactate >200 mL over 15-30 minutes) as first-line treatment if no overt fluid overload present 1
• Rule out mechanical complications before volume loading 2
• Critical pitfall: In RV infarction, avoid excessive volume as it worsens hemodynamics 2

Vasopressor therapy:

• Norepinephrine is the preferred first-line vasopressor to maintain mean arterial pressure 1, 2
• Vasopressin may be considered as adjunctive therapy at 0.03-0.1 units/minute for post-cardiotomy shock or 0.01-0.07 units/minute for septic shock, though it can worsen cardiac function 4

Inotropic therapy:

• Dobutamine (2-20 μg/kg/min) is the first-line inotropic agent to increase cardiac output when signs of low cardiac output persist 1, 2
• Levosimendan may be considered as useful addition in patients with adequate blood pressure (SBP >90 mmHg) and pulmonary congestion 2, 5

Target hemodynamic parameters:

• Wedge pressure <20 mmHg 2
• Cardiac index >2 L/min/m² 2

Step 3: Respiratory Support

Provide oxygen/mechanical ventilation according to blood gases: 2

• Non-invasive positive pressure ventilation for pulmonary edema with respiratory distress (respiratory rate >25 breaths/min, SaO₂ <90%) 2
• Endotracheal intubation and mechanical ventilation for patients unable to achieve adequate oxygenation 2

Step 4: Mechanical Circulatory Support (MCS)

Consider short-term MCS in refractory cardiogenic shock based on age, comorbidities, and neurological function. 1

Key evidence-based recommendations:

• Routine use of IABP is NOT recommended - lacks mortality benefit in randomized trials 1, 2, 6
• IABP should only be considered for hemodynamic instability due to mechanical complications (e.g., ventricular septal defect, acute mitral regurgitation) 2
• Escalation to advanced MCS devices should be guided by invasively obtained hemodynamic data when time allows 2

Device selection considerations:

• Phenotype patients as having left ventricular, right ventricular, or biventricular failure to guide device selection 7
• Despite hemodynamic improvements with various MCS devices, randomized trials incorporating clinical endpoints have been inconclusive 8

Special Considerations

Mechanical complications:

• Treat as early as possible after Heart Team discussion 2
• Emergency cardiac surgery is gold standard for valvular disease-related cardiogenic shock 1

Refractory congestion:

• Ultrafiltration may be considered for patients failing diuretic-based strategies 2

System-Based Approach

Transfer all cardiogenic shock patients to tertiary care centers with: 1, 2

• 24/7 cardiac catheterization capability
• Mechanical circulatory support availability
• Multidisciplinary shock team (associated with improved 30-day all-cause mortality) 2

Regional shock center networks integrated with emergency medical systems have potential to improve outcomes. 8

Critical Pitfalls to Avoid

• Do not delay revascularization - mortality remains ~50% despite modern treatment 2, 3
• Do not routinely use IABP - no mortality benefit demonstrated 1, 2, 6
• Do not overload RV infarction patients with fluids - worsens hemodynamics 2
• Do not delay diagnosis - cardiogenic shock carries nearly 50% in-hospital mortality with multiorgan failure 1