aortic valve – stenosis
description
aortic stenosis denotes some degree of obstruction to flow through the aortic valve due to developmental deformity of the valve. the abnormal valve will be restricted in motion, usually bicuspid or even unicuspid instead of having three leaflets. the stenosis can be varied in severity, but is usually severe or critical if detected in the fetus. the mode and timing of presentation will vary with the severity of valve obstruction. moderate aortic stenosis will usually present with an asymptomatic heart murmur but if severe, the infant will present with cardiac failure. if the obstruction is critical, the neonate will present with circulatory collapse in the first days of life as the duct closes. aortic stenosis can be successfully treated by surgical or balloon valvotomy but the valve will often require replacement or re-operation with growth during childhood. the most severe cases who present in the first week of life or in fetal life have a high mortality in infancy.
diagnosis
if aortic stenosis is only moderate to severe the left ventricle may appear normal or only mildly hypertrophied. the aortic valve may be thickened and domed in systole. there will be an increase in aortic doppler velocity above the normal range for the gestation. if aortic stenosis is critical, there will typically be a dilated, poorly contracting left ventricle with evidence of increased echogenicity of the ventricular walls and papillary muscles of the mitral valve. the mitral valve will be restricted in opening due to the increased left ventricular pressure. there will be mitral regurgitation at high velocity and reversal of the interatrial shunt. the shortening fraction of the left ventricle may be severely reduced. the aortic valve will be thickened and doming. the aortic doppler will be normal or increased depending on the degree of left ventricular compromise, with turbulent flow at the level of the valve. the ascending aorta will be smaller than normal for the gestational age.
differential diagnosis
the complete typical picture cannot be mistaken but primary left ventricular endocardial fibroelastosis may give a similar appearance of the left ventricle with a normal aortic valve.
sonographic features
reversal of interatrial shunt.
restricted mitral valve motion, mitral regurgitation.
dilated, poorly contracting, hypertrophied lv.
increased echogenicity of the lv walls and papillary muscles.
thickened and restricted aortic valve.
turbulent flow across the aortic valve with increased doppler velocities.
aortic root smaller than normal.
associated syndromes
- digeorge
- hydantoin
- noonan
- retinoic acid
- rubella
- turnerís
- 45x
- williams
references
- somerville j in: paediatric cardiology anderson rh, mccartney fj, shinebourne ea, tynan m (eds). churchill livingstone: edinburgh, p977-1001
- allan ld, sharland gk, milburn a, lockhart sm, groves amm, anderson rh, cook ac, fagg nlk prospective diagnosis of 1,006 consecutive cases of congenital heart disease in the fetus j am coll cardiol 23:1452-8
- allan ld, sharland g, cook a in: color atlas of fetal cardiology mosby-wolfe: london, p93-101
- friedman wf in: heart disease in infants, children and adolescents adams fh, emmanouilides gc, riemenschneider ta (eds) williams and wilkins: baltimore, p224-243
- sharland gk, chita sk, fagg n, anderson rh, tynan m, cook ac, allan ld left ventricular dysfunction in the fetus: relation to aortic valve anomalies and endocardial fibroelastosis br heart j 66:219-24
- robertson ma, byrne pj, penkoske pa perinatal management of critical aortic valve stenosis diagnosed by fetal echocardiography br heart j 61:365-7
- achiron r, malinger g, zaidel l, zakut h prenatal sonographic diagnosis of endocardial fibroelastosis secondary to aortic stenosis prenat diagn 8:73-7
- huhta jc, carpenter rj, moise kj, deter rl, ott da, mcnamara dg prenatal diagnosis and postnatal management of critical aortic stenosis circulation 75:573-6