What are the recommendations for anesthesia management in patients with Hypertrophic Obstructive Cardiomyopathy (HOCM)?

Anesthesia Management in Patients with Hypertrophic Obstructive Cardiomyopathy (HOCM)

For patients with hypertrophic cardiomyopathy (HOCM) undergoing anesthesia, factors that aggravate or trigger dynamic outflow obstructions (such as positive inotropic agents, tachycardia, or reduced preload) should be avoided to reduce the risk of hemodynamic instability. 1

Pathophysiological Considerations

HOCM is characterized by:

• Asymmetric septal hypertrophy
• Dynamic left ventricular outflow tract obstruction (LVOTO)
• Systolic anterior motion of the mitral valve (SAM)
• Diastolic dysfunction

Key Hemodynamic Goals

• Maintain adequate preload
• Maintain or increase afterload
• Avoid tachycardia
• Avoid increased myocardial contractility
• Maintain sinus rhythm

Preoperative Management

• Continue beta blockers and/or non-dihydropyridine calcium channel blockers without interruption 1, 2
• Target resting heart rate <60-65 bpm to ensure adequate LV filling 2
• Avoid discontinuing established negative inotropic agents 1
• Consider invasive monitoring (arterial line/central venous pressure) for major surgeries 1

Intraoperative Management

Anesthetic Technique Selection

• General anesthesia considerations:

  • Early-extubation anesthesia (EEA) can be safely used with low-dose opioids and careful titration of anesthetic agents 3
  • Avoid excessive depth of anesthesia that may cause vasodilation
  • Maintain euvolemia

• Neuraxial anesthesia considerations:

  • Use with caution due to risk of sudden sympathetic blockade 4
  • If chosen, consider:
    • Slow, incremental dosing to avoid precipitous drops in blood pressure
    • Epidural with high-dose fentanyl can be effective when carefully titrated 5
    • Maintain adequate preload with IV fluids before neuraxial block

Hemodynamic Management

• Fluid management:

  • Avoid hypovolemia and reduced preload 1
  • Maintain euvolemia with careful fluid administration

• Blood pressure management:

  • Avoid hypotension and reduced afterload 1
  • If hypotension develops:
    • Prioritize intravenous fluid administration to correct hypovolemia
    • Use alpha-agonists (phenylephrine or vasopressin) rather than beta-agonists 1, 2
    • Consider intraoperative echocardiography to evaluate LVOT obstruction 1

• Heart rate and rhythm management:

  • Avoid tachycardia to ensure adequate LV filling 1
  • Maintain sinus rhythm where possible 1
  • In selected cases, intravenous beta-blockade may be necessary to reduce LV contractility and relieve LVOT obstruction 1

Medications to Avoid

• Positive inotropic agents (dobutamine, dopamine, epinephrine) 1, 2
• Pure vasodilators (nitroprusside, nitroglycerin) 2
• High-dose diuretics 2
• Medications that increase heart rate

Postoperative Management

• Continue beta blockers and calcium channel blockers without interruption 2
• Monitor for temporary pacing requirements (high incidence post-procedure) 3
• Watch for atrial arrhythmias 3
• Continue to avoid factors that worsen LVOTO

Special Considerations

• Obstetric patients:

  • Multidisciplinary approach involving cardiology, obstetrics, and anesthesiology 1
  • Epidural and general anesthesia are acceptable with careful hemodynamic management 1
  • Avoid hypotension during delivery 1

• Hypotension management algorithm:

  1. Administer IV fluids to optimize preload
  2. Use alpha-agonists (phenylephrine or vasopressin) to increase afterload 1, 2
  3. Consider intraoperative echocardiography to guide management 1
  4. If needed, administer beta-blockers to reduce contractility and heart rate 1

Monitoring Recommendations

• Consider invasive arterial monitoring for major surgeries
• Central venous pressure monitoring for complex cases
• Consider transesophageal echocardiography (TEE) in situations of hemodynamic instability 1
• Monitor for signs of worsening LVOTO (hypotension unresponsive to fluids, new murmur)

Common Pitfalls to Avoid

• Declaring beta-blocker failure without physiologic evidence of beta-blockade 2
• Using beta-agonists for hypotension, which can worsen LVOTO 1, 2
• Aggressive diuresis, which can worsen LVOT obstruction 2
• Sudden sympathetic blockade with neuraxial techniques 4
• Inadequate preload maintenance during anesthesia 6, 7

By adhering to these principles, the risk of hemodynamic instability and complications in patients with HOCM undergoing anesthesia can be significantly reduced.