AORTIC STENOSIS

CAUSES of AORTIC STENOSIS

1. Infants, children, adolescents - congenital aortic stenosis, congenital subvalvular aortic stenosis, congenital supravalvular aortic stenosis

2. Young adults to middle-aged - calcification and fibrosis of congenitally bicuspid aortic vavlve, rheumatic aortic stenosis

3. Middle-aged to elderly - calcification of bicuspid valve, senile degenerative aortic stenosis, rheumatic aortic stenosis

Aortic stenosis-

-increased gradient across the aortic valve (critical obstruction - peek systolic pressure gradient > 70 mmHG with abnormal cardiac output, or an effective aortic orifice <>

-hypertrophy of the left ventricle (coronary blood flow may become inadequate)

-outflow obstruction - limited the increase in cardiac output required in exercise

-complications - angina, left ventricular failure, arrhythmias

SYMPTOMS of AORTIC STENOSIS (mild and moderate aortic stenosis - asymptomatic; development of any of cardinal symptoms indicates substantial mortality risk)

1. Exertional dyspnoea (due to diastolic dysfunction associated with increased afterload uncompliant hypertrophied LV)

2. Exertional syncope (inability of the left ventricle to increase its output and maintain the cerebral flow during exercise)

3. Sudden death (arrhythmias, acute ischaemia)

4. Pulmonary oedema

5. Angina (disparity between oxygen supply and myocardial oxygen requirements)

SIGNS of AORTIC STENOSIS

1. Ejection systolic murmur (it is heard best at the aortic area, radiates into the base of the neck, its duration is related to the obstruction severity; intensity may decrease in advanced cases with reduced CO)

2. Slow rising carotid pulse, reduced pulse pressure (prolonged in duration and reduced in amplitude - pulsus parvus et tardus)

3. Left ventricular hypertrophy

4. Thrusting left ventricle

5. Signs of left ventricular failure

INVESTIGATIONS in AORTIC STENOSIS

1. ECG - left ventricular hypertrophy and ST changes (downsloping ST segment and T invrsion - strain pattern in leads reflecting the left ventricle), sometimes LBBB; in the elderly, ECG may be normal despite severe stenosis

2. CXR - P-A frequently normal; sometimes left ventricular enlargement and post-stenotic dilatation of ascending aorta; valve calcifications

3. Echocardiography - abnormal aortic valve (calcified and disorganised), hypertrophied left ventricle, the systolic gradient across the aortic valve
   Valve gradient indicative of moderate or severe stenosis- >60mm mercury

4. Cardiac catheterisation - systolic gradient between LV and aorta, post-stenotic dilatation of aorta, regurgitation of AV may be present

Category: Cardiology Notes