Cardiogenic Shock — Summary (Dr. Aws Alherbish)

Definition & Key Concepts

  • Syndrome: Cardiac disorder → low cardiac output → end-organ hypoperfusion.

  • Clinical triad: Hypotension (SBP <90), cardiac index <1.8, elevated filling pressures (e.g., LVEDP ~18).

  • Time-critical: First 30 min = assessment; by 60–90 min = logistics (cath lab/CCU/transfer); next 6–12 h = resuscitation/escalation; by 24 h = trajectory/need for MCS.

Classification Frameworks

  • SHOCK categories: AMI-CS (STEMI/NSTEMI), HF-CS (de novo vs acute-on-chronic cardiomyopathy), post-cardiotomy CS, secondary CS (myocarditis, tachycardia-induced, etc.).

  • SCAI stages: C (stable on inotropes), D (deteriorating), E (extremis).

  • Phenotypes:

    • 1 (Dry–Cold): Non-congested hypoperfusion—lower mortality.

    • 2 (Wet–Cold): Cardiorenal—higher mortality.

    • 3 (Cardiometabolic): Shock liver/severe acidosis—highest mortality.

Pathophysiology & Hemodynamics

  • Vicious circles: Low CO → vasoconstriction/↑afterload, ischemia, sympathetic surge.

  • Goals: Restore perfusion, reduce congestion, decrease myocardial work.

  • Key metrics: LVOT VTI (SV surrogate; <10 cm concerning), cardiac power output (MAP × CO).

  • Forrester lens: Assess perfusion and congestion to guide therapy.

Initial Assessment (≤30 min)

  • Focused Hx/Exam: Perfusion (cold, mental status, urine), congestion (JVP/edema), vitals.

  • Rapid tests: ECG (rule STEMI), POCUS/echo (LV/RV, volume, lungs), CXR; monitor outputs.

  • If pre-arrest: Prioritize stabilization (PLR over fluid bolus, vasoactive boluses, early echo); correct acidosis, calcium, electrolytes.

Management Pillars

  • Etiology-directed: Early revascularization for AMI-CS (primary mortality benefit).

  • Pharmacologic:

    • Pressors/inotropes: Start norepinephrine; add dobutamine or milrinone as needed; avoid dopamine (arrhythmias/ischemia).

    • Begin diuretics once hemodynamically safer (congestion).

    • Aggressive metabolic correction (acidosis, Ca/K/Na).

  • Procedural: PCI/CABG; MCS (IABP less used; Impella or VA-ECMO based on needs).

    • Device choice by urgency, flow requirement, lung involvement, RV, valves/thrombus, access.

    • ECMO ↑afterload; consider LV venting (e.g., Impella).

  • Ancillary: Ventilation (NIV/intubation), antibiotics if infected, delirium control, transfusion targets ~70–80 g/L per clinician judgment.

MCS Strategy & Outcomes

  • Team-based decision: Heart failure, interventional, surgery, intensivist.

  • Candidacy: Age/frailty, comorbidities, and clear exit strategy (recovery, PCI, LVAD, transplant).

  • Timing: Not too early (before pharma failure) or too late (irreversible organ injury).

  • Destinations: Recovery, durable LVAD, heart transplant, or death.

  • Mortality: Still ~40–50%; risk rises with ≥3 vasoactive agents.

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