What is the most appropriate management for a 2-year-old boy with a history of hypertrophic cardiomyopathy (HCM) and aortic stenosis, presenting with increased shortness of breath during physical activity, diastolic murmur, and severe aortic stenosis with left ventricular hypertrophy?

Management of 2-Year-Old with HCM, Severe Aortic Stenosis, and Worsening Symptoms

This child requires urgent surgical intervention with mechanical aortic valve replacement combined with septal myectomy, as he has symptomatic severe aortic stenosis (68%) with concurrent hypertrophic cardiomyopathy causing left ventricular outflow tract obstruction—a life-threatening combination that demands definitive surgical correction. 1

Why Surgical Intervention is Mandatory

Dual pathology requires comprehensive surgical approach:

• This patient has two separate obstructive lesions: fixed valvular aortic stenosis (68%) AND dynamic LVOT obstruction from HCM 1
• The 2024 AHA/ACC HCM guidelines explicitly state that in patients with symptomatic obstructive HCM who have associated valvular aortic stenosis requiring surgical treatment, surgical myectomy provides the opportunity to correct all structural and anatomic issues with a single procedure 1
• Transaortic septal myectomy adds minimal risk to other cardiac procedures, and relief of LVOTO minimizes risk of hemodynamic instability postoperatively 1

Symptomatic severe aortic stenosis at age 2 is a surgical emergency:

• The child has progressive dyspnea with exertion, indicating hemodynamic decompensation 2
• Survival decreases rapidly after symptoms appear in aortic stenosis 2
• At 68% stenosis with symptoms, this represents critical aortic stenosis requiring valve replacement 2

Why Each Alternative is Wrong

A. Reassurance is contraindicated:

• Symptomatic severe aortic stenosis has rapidly declining survival once symptoms develop 2
• The combination of HCM and severe AS creates compounded LVOT obstruction that will progress to sudden death or heart failure 1

C. TAVR is absolutely contraindicated:

• TAVR is not approved for pediatric patients and has no role in 2-year-old children 3, 4
• The aortic annulus in a 2-year-old is far too small for any available TAVR device 1
• TAVR does not address the septal hypertrophy causing additional LVOT obstruction 5

D. Restricting physical activity alone is inadequate:

• While activity restriction is appropriate for HCM patients, it does not treat the underlying severe aortic stenosis 1
• This child already has symptoms at baseline activity levels, indicating advanced disease 1
• Activity restriction without definitive treatment will lead to progressive heart failure and death 2

Surgical Approach for This Patient

Modified surgical technique required for young children:

• The classic transaortic septal myectomy is potentially limited in infants and young children where the aortic annulus is small 1
• The modified Konno procedure has been reported to provide equally satisfactory long-term results for basal obstruction in this age group 1
• This approach allows for aortic valve replacement while simultaneously addressing the septal hypertrophy 1

Valve selection considerations:

• Mechanical valve replacement is typically preferred in young patients to avoid multiple reoperations, though it requires lifelong anticoagulation 3
• The heart team must consider that this child will likely need 2-3 interventions during their lifetime given their young age 3

Critical Post-Operative Management

Immediate post-operative monitoring:

• Intraoperative transesophageal echocardiography is mandatory to assess adequacy of septal myectomy and valve function 1, 6
• Follow-up TTE within 3-6 months is required to evaluate procedural results 1, 6

Long-term surveillance:

• Serial echocardiography every 1-2 years to monitor for residual obstruction, valve function, and progression of hypertrophy 1, 6
• Continued restriction from competitive sports given the underlying HCM diagnosis 1
• Beta-blocker therapy to manage residual HCM symptoms and reduce arrhythmia risk 1

Common Pitfalls to Avoid

• Do not delay surgery waiting for the child to "grow into" a larger valve—symptomatic severe AS requires urgent intervention 2
• Do not treat only the aortic stenosis without addressing the septal hypertrophy, as this leaves significant residual LVOT obstruction 1, 5
• Do not consider TAVR as a "less invasive" option in pediatric patients—it is contraindicated and ineffective for this pathology 3, 4
• Do not rely on medical management alone (beta-blockers, calcium channel blockers) as these do not address fixed valvular stenosis 1, 2