Surgical Interventions for Hypertrophic Cardiomyopathy
Surgical septal myectomy is the preferred first-line intervention for eligible patients with hypertrophic cardiomyopathy (HCM) who have severe drug-refractory symptoms and left ventricular outflow tract (LVOT) obstruction. 1
Patient Selection for Septal Reduction Therapy
Septal reduction therapy should only be considered for patients who meet ALL of the following criteria:
- Clinical criteria: Severe dyspnea or chest pain (usually NYHA class III or IV) or other exertional symptoms (syncope, near-syncope) that interfere with daily activities despite optimal medical therapy
- Hemodynamic criteria: Dynamic LVOT gradient ≥50 mmHg at rest or with physiologic provocation
- Anatomic criteria: Adequate septal thickness to safely perform the procedure 1
Surgical Options
1. Surgical Septal Myectomy (First-line option)
Surgical septal myectomy is the gold standard and should be the first consideration for most eligible patients with HCM and severe drug-refractory symptoms 1. The procedure involves:
- Transaortic approach: Standard technique for isolated subaortic obstruction (most common)
- Extended myectomy: Resection of septal muscle from the base of the aortic valve to beyond the level of mitral-septal contact
- Transapical myectomy: Used for midventricular or apical obstruction 2
Benefits:
- Relief of LVOT obstruction in >90% of cases
- Significant improvement in symptoms in 89-95% of patients
- Low perioperative mortality (<1% for isolated myectomy) 3, 4
2. Alcohol Septal Ablation (Alternative option)
Alcohol septal ablation should be considered when:
- Surgery is contraindicated due to serious comorbidities
- Patient has advanced age making surgical risk unacceptable
- Patient strongly prefers a less invasive approach after thorough discussion 1, 5
Procedure:
- Selective injection of alcohol into septal perforator artery to create controlled infarction
- Requires appropriate septal anatomy and target vessel accessibility
- Echocardiographic guidance to confirm proper targeting 5
Limitations:
- Not recommended for patients <21 years of age
- Discouraged in patients <40 years if myectomy is viable
- Uncertain effectiveness with marked septal hypertrophy (>30 mm) 1, 5
Contraindications for Septal Reduction Therapy
Septal reduction therapy should NOT be performed in:
- Asymptomatic patients with normal exercise tolerance
- Patients whose symptoms are controlled with medical therapy
- Patients without access to programs dedicated to HCM care 1
Comparison of Surgical Options
| Factor | Surgical Myectomy | Alcohol Septal Ablation |
|---|---|---|
| Mortality | <1% (isolated procedure) | ≤1% in experienced centers |
| Symptom relief | >90% | 70-90% |
| Need for pacemaker | <5% | 10-20% |
| Recovery time | Longer | Shorter |
| Long-term data | Extensive | Limited |
Operator Experience Requirements
Both procedures should ONLY be performed by:
- Individual operators with ≥20 procedures experience OR
- Operators working in dedicated HCM programs with ≥50 procedures total experience 1
Special Considerations
Concomitant cardiac disease: If the patient requires other cardiac surgical procedures (e.g., CABG, mitral valve repair), surgical myectomy should be performed rather than alcohol ablation 1
Mitral valve abnormalities: When mitral valve pathology contributes to obstruction, surgical approaches may include additional procedures (plication, valvuloplasty, papillary muscle relocation) 1
Apical HCM: In highly selected patients with apical HCM, severe symptoms, preserved EF, and small LV cavity size, apical myectomy may be considered 1
Post-Procedure Care
- Continuous cardiac monitoring for 48-72 hours
- Echocardiographic follow-up at 1,3,6, and 12 months
- Monitoring for complications including heart block, ventricular arrhythmias, and post-procedural pain 5
Remember that septal reduction therapy should only be performed in centers with comprehensive HCM programs that provide longitudinal and multidisciplinary care for patients with HCM.