By : Noelle Harrison-Ivanova
Aortic stenosis
(Stenosis - narrowing)
Life expectancy of someone who has contracted aortic stenosis : 1-2 years
Who is affected by it: mainly the elderly but it could also affect people born with bicuspid valves rather than tricuspid valves.
Risk factors: diabetes, high blood pressure, chronic kidney disease, abnormal lipids etc.
Symptoms of aortic stenosis: angina (chest pain), syncope (fainting episodes), shortness of breath, fatigue, difficulty sleeping, heart murmurs etc.
What is Aortic stenosis? How is it caused? How does it affect the body?
Aortic stenosis is a heart disease which impairs the heart's ability to pump out blood overtime which ultimately causes heart failure. This condition is caused by mechanical stress of the aortic valve overtime which causes the accumulation of calcium deposits on the aortic valve (hence why this condition is commonly found in people ages 60 and above). These calcium deposits make the valve stiff and narrow which means that during systole (when the aortic valve opens to allow blood to flow around the body ) the valve doesn’t fully open causing obstruction to the left ventricular outflow resulting in a decrease in cardiac output (the quantity of blood which the heart pumps out each minute). The rate of blood flow throughout the different parts of the body is dependent on the cardiac output. So if the cardiac output is decreased then the blood flow throughout the body is reduced and vital organs - such as skeletal muscles, the brain, kidneys etc. are deprived of oxygen and nutrients necessary to carry out respiration in order to produce the energy needed to efficiently perform their functions such as contracting to bring about movement to the skeleton (the function of skeletal muscle). There is also an increased risk of infection if organs are not supplied with an adequate amount of blood, because the blood contains white blood cells which fight against infection (invading pathogens).
How does Aortic stenosis cause heart failure?
With Aortic stenosis the heart has to pump harder in order to push blood through the narrowed aortic valve. This pressure overload causes concentric hypertrophy, which is an abnormal increase in the left myocardial mass. The myocardial mass crowds into the ventricular chamber space, therefore shrinking the chamber space. This in turn means that there is a filling dysfunctioning - where the volume of blood the ventricular chamber can hold is reduced which ultimately leads to diastolic heart failure ( when the ventricle loses its flexibility and is incapable of relaxing).
Treatment
Surgical valve replacement (mechanical or biological)
Mechanical valve replacement
● no rejection
● Often used for younger people because it lasts longer
● However mechanical valves can damage red blood cells and anti-clotting drugs (anticoagulants) are needed
Biological valve replacement
● biological valves do not damage red blood cells
● Continuous anticoagulation is not required
● However biological valves can harden and need replacing
Big thanks to these sources which helped me to conduct this research:
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