Aortic Stenosis
Key Facts
Narrowing of the aortic valve resulting in obstruction to the left ventricular stroke volume, leading to symptoms of chest pain, breathlessness, syncope and fatigue
Epidemiology
Primarily a disease of ageing
Congenital is the second most common cause
Symptoms occur when valve area is 1/4 of normal
The most common type of valvular disease in the Western world
Normal aortic valve area 3-4 cm^2
Types
Supravalvular e.g. congenital fibrous diaphragm above the aortic valve
Subvalvular e.g. congenital condition in which a fibrous ridge or diaphragm is situated immediately below the aortic valve
Valvular - most common
Main Causes
Calcification of a congenital bicuspid aortic valve resulting in stenosis
Rheumatic heart disease - rare now due to eradication
Calcific aortic valvular disease (CAVD) - essentially calcification of the aortic valve resulting in stenosis, most commonly seen in elderly
Risk Factors
Congenital bicuspid aortic valve (BAV) predisposes to stenosis and regurgitation - bicuspid valves are more likely to develop stenosis
Congenital BAV is predominant in males
Pathophysiology
This results in increased left ventricular pressure and compensatory left ventricular hypertrophy
A compensatory mechanism ensues, which leads to exhausted left ventricular function as hypertrophy requires increased blood demand
Narrowing causes obstructed left ventricular emptying and an increased afterload
Clinical Presentation
Sudden death
Classic symptoms: syncope, angina, heart failure, dyspnoea on exertion due to heart failure
Slow rising carotid pulse and decreased pulse amplitude
Heart sounds
Think aortic stenosis in ANY elderly person with chest pain, exertion dyspnoea or syncope (loss of conscious due to lack of blood)
Soft or absent second heart sound
Prominent 4th heart sound due to left ventricular hypertrophy
Ejection systolic murmur-crescendo-decrescendo character
Loudness doesn't tell you anything about severity
Differential Diagnosis
Aortic regurgitation
Subacute bacterial endocarditis
Treatment
Diagnosis
ECG - left ventricular hypertrophy, left atrial delay, left ventricular 'strain' pattern
CXR - left ventricular hypertrophy & calcified aortic valve
Echocardiogram - left ventricular hypertrophy, dilation and ejection fraction.
Vasodilators are contraindicated in severe aortic stenosis
Surgical aortic valve replacement is the definitive treatment
Limited role for medication due to aortic stenosis being mechanical
An alternative for surgical replacement is Transcutaneous Aortic Valve Implantation
Rigorous dental hygiene/care due to the increased risk of infective endocarditis