What are the steps in managing cardiogenic shock?

Step-by-Step Management of Cardiogenic Shock

The management of cardiogenic shock requires immediate recognition, rapid hemodynamic stabilization with vasopressors and inotropes, early invasive monitoring, prompt revascularization when indicated, and selective escalation to mechanical circulatory support based on phenotype-specific hemodynamic criteria. 1, 2

Step 1: Early Recognition and Diagnosis

Diagnose cardiogenic shock using both clinical and hemodynamic criteria within the first 30 minutes of presentation. 1, 2

Clinical Criteria:

• Systolic blood pressure <90 mmHg for ≥30 minutes OR requirement for vasopressors/inotropes to maintain SBP >90 mmHg 1, 2
• Evidence of end-organ hypoperfusion including:
  • Lactate >2 mmol/L 1, 2
  • Urine output <0.5 mL/kg/h 3
  • Altered mental status 1, 3
  • Cool extremities with peripheral vasoconstriction 1, 3
  • Acute liver injury (bilirubin ≥1.3 mg/dL predicts worse outcomes) 3
  • Acute kidney injury 3

Hemodynamic Criteria:

• Cardiac index <1.8 L/min/m² without support OR <2.2 L/min/m² with support 1, 3
• Cardiac power output <0.6 W 1, 2
• Pulmonary capillary wedge pressure >15 mmHg 1, 3

Common pitfall: Do not miss "preshock" patients who maintain near-normal blood pressure through compensatory vasoconstriction despite severe hypoperfusion—these patients have 43% in-hospital mortality and lower cardiac output than hypotensive shock patients. 1

Step 2: Immediate Stabilization (First 30-60 Minutes)

Airway and Breathing:

Intubate and mechanically ventilate patients with respiratory failure or severe hemodynamic instability. 4 Respiratory failure is common in cardiogenic shock and many patients require invasive mechanical ventilation to reduce work of breathing and oxygen consumption. 4

Circulation - Pharmacologic Support:

Initiate norepinephrine as the first-line vasopressor when mean arterial pressure requires pharmacologic support. 1, 2, 4 Norepinephrine is preferred over other vasopressors based on limited comparative data. 1

Add dobutamine (2-20 μg/kg/min) as the first-line inotrope to increase cardiac output and restore organ perfusion. 2, 4

Use inotropes and vasopressors at the lowest effective dose for the shortest duration possible because they increase myocardial oxygen demand, ischemic burden, and risk of malignant arrhythmias. 1

Alternative inotropic agents:

• Milrinone may be considered in patients on beta-blockers, as its mechanism is independent of beta-adrenergic receptors 1
• Retrospective analyses show similar outcomes between dobutamine and milrinone 1

Volume Management:

Administer fluid challenge (saline or Ringer's lactate >200 mL over 15-30 minutes) as first-line treatment if there are no signs of overt fluid overload. 2 However, recognize that most cardiogenic shock patients have elevated filling pressures and require decongestion rather than volume expansion. 1

Step 3: Diagnostic Assessment (Within First 2 Hours)

Immediate Echocardiography:

Perform point-of-care echocardiography immediately to identify the etiology and phenotype of shock. 1, 2, 4 This determines whether shock is:

• Left ventricular-dominant (most common)
• Right ventricular-dominant
• Biventricular
• Due to mechanical complications (free wall rupture, ventricular septal defect, papillary muscle rupture) 1

ECG:

Obtain 12-lead ECG immediately to identify acute myocardial infarction requiring emergent revascularization. 1, 2

Coronary Angiography:

Perform immediate coronary angiography (within 2 hours) with intent to revascularize in AMI-related cardiogenic shock. 2 Early revascularization is the only intervention proven to reduce mortality in AMI-cardiogenic shock. 1, 5

Revascularize the culprit lesion only in multivessel disease with cardiogenic shock—complete revascularization at index procedure increases mortality. 1

Step 4: Invasive Hemodynamic Monitoring

Place a pulmonary artery catheter early in patients not responding to initial therapy or with unclear shock phenotype. 1, 2, 6 Recent observational evidence demonstrates that PAC use is associated with improved outcomes in cardiogenic shock. 1, 6

Phenotype Identification Using Hemodynamics:

Left Ventricular-Dominant Shock: 1

• Cardiac power output <0.6 W
• Pulmonary artery pulsatility index (PAPi) >1.0
• Right atrial pressure <15 mmHg
• PCWP >15 mmHg

Right Ventricular-Dominant Shock: 1

• Cardiac power output <0.6 W
• PAPi <1.0
• Right atrial pressure >15 mmHg
• PCWP <15 mmHg

Biventricular Shock: 1

• Cardiac power output <0.6 W
• PAPi >1.0 or <1.0
• Right atrial pressure >15 mmHg
• PCWP >15 mmHg

Step 5: SCAI Staging and Risk Stratification

Classify shock severity using the SCAI A-E staging system to guide escalation decisions: 1, 3, 2

• Stage A (At Risk): Normal hemodynamics, at risk for shock
• Stage B (Beginning): Relative hypotension without hypoperfusion
• Stage C (Classic): Hypotension with hypoperfusion requiring intervention
• Stage D (Deteriorating): Failing to respond to initial interventions
• Stage E (Extremis): Cardiac arrest, requiring CPR and/or ECMO

Mortality increases stepwise through stages A to E. 3

Step 6: Management Goals and Ongoing Care

Focus on four primary management goals: 1

1. Decongestion: Reduce elevated filling pressures while maintaining perfusion 1
2. Restore perfusion: Target cardiac index >2.0-2.2 L/min/m² 3, 2
3. Limit multiorgan dysfunction: Prevent progression to irreversible end-organ failure 1
4. Assess risk/benefits of treatment escalation: Continuously evaluate response to therapy 1

Step 7: Mechanical Circulatory Support Decision-Making

Criteria for Refractory Shock Requiring MCS Consideration:

Consider temporary mechanical circulatory support when: 1, 2

• Cardiac power output <0.6 W despite optimal medical therapy 1
• Cardiac index <2.2 L/min/m² despite inotropes/vasopressors 1
• Lactate remains elevated or rising 1
• Progressive end-organ dysfunction 1

Contraindications to MCS:

• Anoxic brain injury 1
• Irreversible end-organ failure 1
• Prohibitive vascular access 1
• Do Not Resuscitate order 1

Device Selection Based on Phenotype:

Do NOT routinely use intra-aortic balloon pump (IABP) in cardiogenic shock—randomized trials show no mortality benefit. 2, 5

For LV-dominant shock with CPO <0.6 W and PAPi >1.0: Consider percutaneous ventricular assist devices (Impella) or VA-ECMO based on severity and institutional capabilities. 1

For RV-dominant shock with PAPi <1.0: Consider right ventricular support devices or VA-ECMO. 1

For biventricular shock: VA-ECMO is typically required for adequate biventricular support. 1

Step 8: Transfer and Multidisciplinary Care

Transfer patients with SCAI Stage C or higher cardiogenic shock to a tertiary care center with: 2

• 24/7 cardiac catheterization capability
• Full spectrum mechanical circulatory support availability
• Multidisciplinary shock team 1, 2

Assemble an interdisciplinary shock team early including cardiology, cardiac surgery, critical care, palliative care, and other specialists to optimize decision-making regarding escalation, de-escalation, and end-of-life care. 1

Step 9: Exit Strategy Planning

Identify potential exit strategies based on patient factors, clinical trajectory, and center capabilities: 1

• Recovery: Myocardial recovery with weaning of support
• Durable LVAD: Bridge to destination therapy or transplant
• Heart transplantation: For eligible candidates
• Transition to comfort care: When aggressive therapies are futile (SCAI Stage E with contraindications) 1

Critical Pitfalls to Avoid:

1. Delaying revascularization in AMI-cardiogenic shock—this is the only proven mortality-reducing intervention 1, 5
2. Performing complete revascularization at index procedure in multivessel disease—increases mortality 1
3. Routinely using IABP—no evidence of benefit 2, 5
4. Missing normotensive shock (preshock)—has higher mortality than recognized 1
5. Delaying PAC placement in unclear or refractory shock—associated with improved outcomes 1, 6
6. Using high-dose or prolonged inotropes/vasopressors without considering MCS—increases myocardial oxygen demand and arrhythmias 1
7. Failing to involve palliative care early in SCAI Stage E or patients with contraindications to aggressive therapy 1