Narrowing in the LV outflow tract creates an increased workload on the heart.
1 - narrowed aortic valve
Flow patterns are normal but blood flow to the aorta
is reduced as indicated by the broken white arrows.
Obstructive defect...Generally, severe stenoses in the neonatal period are associated with CHF symptoms and/or cyanosis depending on the location of the lesion.
Malformation of the aortic valve that causes obstruction to ejection of blood from LV.
Produces LV hypertrophy, decreased LV function, and compromised flow to the myocardium.
Common to have associated lesions (PDA, VSD, Coarct).
Neonates may present with critical aortic stenosis
Neonates who present with critical aortic stenosis and low cardiac output have reduced or absent pulses, poor perfusion, and CHF.
CXR demonstrates normal to minimal enlargement of heart size, rounding of the cardiac apex, left atrial enlargement if severe stenosis, and pulmonary congestion.
IV, O2, Monitor.
3cc/kg/hr D10W for infants under 1 year of age, D5W if over 1 year.
Check pulse ox pre-ductal and post-ductal.
Severe CHF may benefit from intubation with positive pressure ventilation and Lasix
Stabilization of the neonate with critical aortic stenosis requires prostaglandin therapy. Opening the ductus with PGE can restore systemic blood flow.
Inotropic drugs to increase cardiac output if needed.
Epinephrine, Dopamine, Dobutamine.
Foley catheter insertion to follow renal perfusion and urine output.
ABG to follow acidosis.