Children with mild or moderate aortic stenosis may get worse as they get older. They also run the risk of developing an infection of the heart valves (bacterial endocarditis).
The following are a few important aspects about Angina Pectoris in Aortic Stenosis. [8][9][10]
The hypertrophied left ventricle and the prolonged ejection time (the time for the heart to eject blood) result in an increased myocardial oxygen requirements. The elevated diastolic filling pressure also reduces the gradient between the aorta and the right atrium ("the height of the waterfall") which normally drives coronary blood flow. The hypertrophied ventricle may also compress the capillaries. All of the above reasons lead to a reduction in coronary blood flow even in the absence of obstructive epicardial stenoses. This may result in subendocardial ischemia during stress or exercise.
Left untreated, the average survival is 5 years after the onset of angina in the patient with aortic stenosis.
The mechanism of syncope secondary to aortic stenosis remains unclear. Left untreated, the average survival is 3 years after the onset of syncope in the patient with aortic stenosis.
Three theories have been hypothesized to explain the relationship between aortic stenosis and syncope:[11]
Severe aortic stenosis results in a nearly fixed cardiac output. During exercise, the peripheral vascular resistance will decrease as the blood vessels dilate to allow the skeletal muscles to receive more blood. This decrease in peripheral vascular resistance is normally compensated by an increase in the cardiac output. Since patients with severe aortic stenosis cannot increase their cardiac output, the blood pressure falls and the patient will develop syncope due to decreased blood flow to the brain.
During exercise, the high pressures generated in the hypertrophied left ventricle may cause a vasodepressor response, which subsequently results in peripheral vasodilation. As a consequence, the blood flow to the brain may decrease. Therefore, due to the fixed outwards blood flow obstruction at the level of the stenosed aortic valve, it may be impossible for the heart to increase its output to offset the peripheral vasodilation.
CHF in the setting of aortic stenosis is due to a combination of systolic dysfunction (a decrease in the ejection fraction) and diastolic dysfunction (elevated filling pressure of the left ventricle). Left untreated, the average survival is 5 years after the onset of angina, 3 years after the onset of syncope, and 1 year after the onset of congestive heart failure. [12][13][14]
Symptoms of left ventricular failure include the following: