AORTIC STENOSIS



General Considerations  Most often as result of degeneration of bicuspid aortic valve Less commonly rheumatic heart disease or secondary to degeneration of a tricuspid aortic valve in person > 65  Location Supravalvular Uncommon Associated with William’s Syndrome Hypercalcemia Elfin facies Pulmonary stenoses Hypoplasia of aorta Stenoses in Renal, celiac, superior mesenteric arteries Valvular Most common Either congenital (from a bicuspid aortic valve) or acquired Bicuspid aortic valve is the most common congenital cardiac anomaly 0.5 –2% Subvalvular Associated with Hypoplastic left heart syndrome Idiopathic Hypertrophic Subaortic Stenosis Hypertrophic cardiomyopathy Subaortic fibrous membrane  Types Congenital aortic stenosis (more common) Most frequent congenital heart disease associated with intra-uterine growth retardation (IUGR) Subvalvular (30%) Valvular (70%) Degeneration of bicuspid valve Supravalvular Acquired aortic stenosis Rheumatic valvulitis Almost invariably associated with mitral valve disease Fibrocalcific senile aortic stenosis Degenerative  Clinical Findings Asymptomatic for many years Classical triad Angina Syncope Shortness of breath (heart failure) Systolic ejection murmur Carotid pulsus parvus et tardus Diminished aortic component of 2nd heart sound Sudden death in severe stenosis after exercise Diminished flow in coronary arteries causes ventricular dysrhythmias and fibrillation Decompensation leads to left ventricular dilatation and pulmonary venous congestion Imaging Findings  In older children or young adults Prominent ascending aorta Poststenotic dilatation of ascending aorta Due to turbulent flow Left ventricular heart configuration Normal-sized or enlarged left ventricle Concentric hypertrophy of left ventricle produces a relatively small left ventricular chamber with thick walls Heart size is frequently normal In adults >30 years Prominent ascending aorta Poststenotic dilatation of ascending aorta Due to turbulent flow Calcification of aortic valve (best seen on RAO) In females, usually indicates hemodynamically significant aortic stenosis Calcification of the valve usually indicates a gradient across valve of > 50mm Hg Calcification begins in bicuspid and rheumatic valve in 4th decade but not until > 65 in tricuspid DDx Calcification of aortic annulus in elderly Calcified coronary artery ostium (thickened cusp echoes only in diastole) Normal to enlarged left ventricle Echocardiographic findings Thickened and calcified aortic valve with multiple dense cusp echoes throughout cardiac cycle (right > non-coronary > left coronary cusp) Decreased separation of leaflets in systole with reduced opening orifice (13-14 mm = mild AS; 8-12 mm = moderate AS; <8 mm = severe AS) ± Doming in systole Dilated aortic root Increased thickness of LV wall (= concentric LV hypertrophy) Hyperdynamic contraction of LV (in compensated state) Decreased mitral EF slope (reduced LV compliance) LA enlargement Increased aortic valve gradient (Doppler) Decreased aortic valve area (unreliable) Angiographic findings   Simultaneous LV and aortic pressures recordings yield valve gradients from left heart catheterization Angiographic technique uses standard RAO left ventriculogram and an aortogram using a 40° LAO projection A non-calcified, bicuspid valve reveals thickening and doming of the valve leaflets in systole A jet of non-opacified blood is visible through stenotic valve Congenitally bicuspid valves still usually have three aortic sinuses with one large non-coronary sinus equal in size to the other two Calcification begins in the bicuspid and rheumatic valve in the 4th decade but not until >65 in tricuspid In rheumatic disease, the aortic valve commissures usually fuse whereas they do not in the degenerated tricuspid valve  Differentiating Causes of Aortic Stenosis Etiology/Findings Calcification Other clues Congenital Bicuspid Valve 30’s Jet effect on aortogram Degeneration of Tricuspid Valve > 65 Coronary artery ca++ Commissures don’t fuse Rheumatic dz in Tricuspid Valve 30’s here; teens in 3rd world countries MS or MR almost always present; commissures fuse   Valve areas   Normal Mild Severe Critical 2.6-3.5cm2 1.3-1.7 1.0 0.5

 

Aortic Stenosis. Frontal radiograph on left demonstrates isolated enlargement of the ascending aorta (white arrow). The left ventricle is enlarged (red arrow) and the heart is mildly enlarged overall. The lateral view on the right demonstrates calcifications in the region of the aortic valve leaflets (circle). generally, the aortic valve lies above a line drawn from the carina to the junction of the diaphragm with the anterior chest wall. The mitral valve lies below the line.                 retrieved from: http://www.learningradiology.com/archives04/COW%20118-Aortic%20Stenosis/ascorrect.htm