Aortic Stenosis

Last updated 2015 - Written by Benjamin Marsh MD

Definition: A group of lesions that produce LV outflow tract obstruction, 10% of all CHD, 4x as common in males.

Clinical Manifestations

  • CHF develops within the first few months of life with critical AS. They almost always have left sided hypoplasia, often requiring a Norwood followed by a Fontan.
  • Exertional chest pain or syncope may occur with severe AS. Narrow pulse pressure may be seen on PE.
  • Patients with mild to moderate AS are asymptomatic.
  • PE: a harsh grade 2- 4/6 SEM best heard at 2nd R intercostal space or 3rd L intercostal space radiating to the neck. Valvular AS may have ejection click. They may have a systolic thrill at URSB, suprasternal notch, or over the carotids. Aortic regurge is often seen with bicuspid aortic valve and discrete subvalvular stenosis and has a high-pitched, early diastolic decrescendo murmur. In supravalvular AS the Coanda effect may give rise to R>L arm B/P. Neonates with critical AS may have weak and thread peripheral pulses.
  • ECG: Often WNL. LVH or strain pattern can be seen in severe cases.
  • CXRtypically WNL, but valvular AS can have a dilated ascending aorta, substantial AR or CHF can cause cardiomegaly.
  • Echo is diagnostic.

Management

Indications for surgery:

  • Failed valvuloplasty, resultant severe AR.
  • Surgery is indicated in children with symptoms with a strain pattern on the ECG or abnormal exercise test.
  • Either aortic valve commissurotomy, aortic valve replacement (using mechanical or biological valves), or the Ross procedure is performed.
  • The advantage of the mechanical valve are more durable but lead to a thrombotic diathesis requiring warfarin. Biologic valves deteriorate or calcify in 10-20 years.
  • In the Ross procedure the pulmonary valve replaces the aortic valve, and an aortic or a pulmonary allograft replaces the pulmonary valve. The autologous pulmonary valve has documented long-term durability, does not require anticoagulation and there is evidence of the autograft’s growth. The patient’s own aortic valve may be used for pulmonary position after aortic valvotomy AKA the “double” Ross procedure.
  • In discrete subaortic stenosis, a systolic pressure gradient>30 mm Hg or the onset of an AR is an indication for an elective excision of the membrane. Recurrance rates are lower if performed after 10yo.
  • In tunnel-type subaortic stenosis, a pressure gradient ≥50 mm Hg is an indication. Valve replacement following aortic root enlargement (Kono procedure) may be performed.
  • In supravalvular AS, the peak pressure gradient greater than 50 to 60 mm Hg, severe LVH, or appearance of new AR is an indication for surgery. Widening of the stenotic area using a diamond-shaped fabric patch may be performed.
  • Asymptomatic pts can be followed expectantly with echos every 1-2 years. Exercise stress tests are performed in those wishing to participate in sports.
  • In critically ill infants with CHF, anticongestive measures with pressors and diuretics, with or without PGE infusion in preparation for balloon valvuloplasty or surgery.

Indications for balloon valvuloplasty:

  • Symptomatic patients with a catheterization pressure gradient ≥50 mm Hg
  • Asymptomatic patients with a catheterization pressure gradient >60 mm Hg
  • Asymptomatic patients with ST or T wave changes at rest or during EST with a catheterization pressure gradient of>50 mm Hg.
  • Asymptomatic patients with a catheterization pressure gradient >50 mm Hg who want to play competitive sports
  • No indication for catheterization pressure gradient is <40 mm Hg.
  • Balloon valvulopasty has a survival rate of 50%.  Serious complications include; hemorrhage, loss of femoral artery pulse, valve leaflet avulsion and perforation of the mitral valve or LV.

Prognosis

  • Mild asymptomatic stenosis may worsen with aging as the result of calcification of the valve cusps.
  • Mild AS (with Doppler gradient <40 mm Hg) does not require activity limitations
  • Moderate AS (40-70 mm Hg) requires restriction from high dynamic or static competitive athletics.
  • Severe AS ( >70 mm Hg) is restricted from all competitive sports.
  • Annual follow-up is needed for post-surgical or catheter procedure for development of AR (seen in 10-30%). Discrete subaortic membrane recurs in 25% to 30% after surgical resection.
  • Anticoagulation with warfarin + ASA 81mg daily is needed after a prosthetic mechanical valve replacement maintaining the INR 2.5-3.5 for the first 3 months and 2-3 thereafter.
  • Those with biologic valves need only ASA.
  • Sub-acute bacterial endocarditis prophylaxis is required after placement of prosthetic material or valve

Sources: Park Ch 3, Nadas’ Ch 33, Nelsons Ch 421,