Cardiogenic Shock

Cardiogenic Shock

David Ray Velez, MD

Table of Contents

Definition
Evaluation
Treatment

See Also:

Definition

Definition: Inadequate Tissue Perfusion to Meet End-Organ Needs Due to a Cardiac Etiology

High Mortality (50-75%)

Causes of Cardiogenic Shock

  • Cardiomyopathy
    • Myocardial Infarction – The Most Common Cause
    • Acute Decompensated Heart Failure (ADHF)
    • Blunt Cardiac Injury
    • Myocarditis
    • Advanced Septic Shock
    • Drug-Induced
  • Arrhythmia
  • Mechanical
    • Valve Pathology (Insufficiency, Rupture or Stenosis)
    • Atrial Myxoma

Evaluation

Clinical Manifestations

  • Classic Presentation:
    • Severe Hypotension
    • Signs of Systemic Hypoperfusion
    • Respiratory Distress Due to Pulmonary Congestion
  • Signs of Systemic Hypoperfusion:
    • Cold/Pale Extremities
    • Oliguria
    • Altered Mental Status
  • Metabolic Acidosis
  • Lactic Acidosis
  • Signs of Underlying Disorder:
    • Myocardial Infarction: Chest Pain, Shortness of Breath, Diaphoresis
    • Heart Failure: Dyspnea, Fatigue, Volume Overload

Evaluation

  • Echocardiogram
  • EKG – Evaluating for Arrhythmias or ST Elevations
  • Chest XRray – May See Signs of Fluid Overload (Pulmonary Vascular Congestion, Pulmonary Edema, Pleural Effusion)
  • Labs: BNP, Troponin, and Routine Labs
  • Pulmonary Artery Catheter (PAC)
    • Should Not be Used Routinely
    • May Help Particularly When Trying to Differentiate the Effects of a Combined Cardiogenic and Hypovolemic Shock

Hemodynamic Changes

  • Blood Pressure: Significantly Decreased
  • Preload (PCWP): Significantly Increased
    • *Cardiogenic Shock Due to Right Ventricular Failure Causes Decreased PCWP
  • Contractility (CO/CI): Decreased
  • Afterload (SVR): Increased
  • SvO2: Decreased

Treatment

Vasopressors

  • Vasopressors are the Primary Treatment for Cardiogenic Shock
  • Norepinephrine
    • Generally the Preferred Agent
  • Inotropes (Dobutamine)
    • *Historically the Agent of Choice but Newer Evidence Shows Increased Risk of Arrhythmia and a Trend to Increased Mortality
  • Levosimendan (Simdax)
    • Mechanism: Calcium-Sensitizing Inodilator
      • Increases Myocardial Contractility without Increasing Myocardial Oxygen Consumption
      • Causes Vasodilation to Decrease Preload and Afterload
    • Newer Agent that is Being Used in ADHF/Cardiogenic Shock to Possibly Prevent Cardiac Ischemia

Fluid Management

  • Generally Avoid Aggressive IV Fluid Resuscitation – Can Cause Pulmonary Edema
  • May Need an Initial IV Fluid Bolus to Maintain Preload
  • May Require Diuresis if Evidence of Fluid Overload (Pulmonary Edema, etc.)

Reperfusion in Myocardial Ischemia (MI)

  • Cardiogenic Shock Due to MI is an Indication for Emergent Reperfusion
  • Approaches:
    • Percutaneous Coronary Intervention (PCI)
    • Fibrinolysis
    • Coronary Artery Bypass Graft (CABG)
  • *See Myocardial Ischemia (MI)

Mechanical Circulatory Support

  • Should Not be Used Routinely
  • Indications:
    • Severe Mechanical Defects
    • Rapid Deterioration
    • Refractory Shock
  • Methods:
    • Intra-Aortic Balloon Pump (IABP)
    • Left Ventricular Assist Device (LVAD)
    • Extracorporeal Membrane Oxygenation (ECMO)