Cardiogenic Shock — Summary (Dr. Aws Alherbish)
Definition & Key Concepts
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Syndrome: Cardiac disorder → low cardiac output → end-organ hypoperfusion.
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Clinical triad: Hypotension (SBP <90), cardiac index <1.8, elevated filling pressures (e.g., LVEDP ~18).
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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
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SHOCK categories: AMI-CS (STEMI/NSTEMI), HF-CS (de novo vs acute-on-chronic cardiomyopathy), post-cardiotomy CS, secondary CS (myocarditis, tachycardia-induced, etc.).
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SCAI stages: C (stable on inotropes), D (deteriorating), E (extremis).
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Phenotypes:
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1 (Dry–Cold): Non-congested hypoperfusion—lower mortality.
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2 (Wet–Cold): Cardiorenal—higher mortality.
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3 (Cardiometabolic): Shock liver/severe acidosis—highest mortality.
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Pathophysiology & Hemodynamics
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Vicious circles: Low CO → vasoconstriction/↑afterload, ischemia, sympathetic surge.
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Goals: Restore perfusion, reduce congestion, decrease myocardial work.
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Key metrics: LVOT VTI (SV surrogate; <10 cm concerning), cardiac power output (MAP × CO).
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Forrester lens: Assess perfusion and congestion to guide therapy.
Initial Assessment (≤30 min)
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Focused Hx/Exam: Perfusion (cold, mental status, urine), congestion (JVP/edema), vitals.
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Rapid tests: ECG (rule STEMI), POCUS/echo (LV/RV, volume, lungs), CXR; monitor outputs.
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If pre-arrest: Prioritize stabilization (PLR over fluid bolus, vasoactive boluses, early echo); correct acidosis, calcium, electrolytes.
Management Pillars
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Etiology-directed: Early revascularization for AMI-CS (primary mortality benefit).
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Pharmacologic:
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Pressors/inotropes: Start norepinephrine; add dobutamine or milrinone as needed; avoid dopamine (arrhythmias/ischemia).
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Begin diuretics once hemodynamically safer (congestion).
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Aggressive metabolic correction (acidosis, Ca/K/Na).
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Procedural: PCI/CABG; MCS (IABP less used; Impella or VA-ECMO based on needs).
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Device choice by urgency, flow requirement, lung involvement, RV, valves/thrombus, access.
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ECMO ↑afterload; consider LV venting (e.g., Impella).
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Ancillary: Ventilation (NIV/intubation), antibiotics if infected, delirium control, transfusion targets ~70–80 g/L per clinician judgment.
MCS Strategy & Outcomes
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Team-based decision: Heart failure, interventional, surgery, intensivist.
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Candidacy: Age/frailty, comorbidities, and clear exit strategy (recovery, PCI, LVAD, transplant).
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Timing: Not too early (before pharma failure) or too late (irreversible organ injury).
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Destinations: Recovery, durable LVAD, heart transplant, or death.
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Mortality: Still ~40–50%; risk rises with ≥3 vasoactive agents.