Valvular diseases Flashcards
What is aortic stenosis (AS)?
Refers to the narrowing and tightening of the aortic valve.
This leads to reduced blood flow from the left ventricle into the aorta and ultimately to the rest of the body.
Explain the pathophysiology of aortic stenosis?
Normal function:
- aortic valve opens to allow blood to be pumped from the left ventricle into the aorta and to the rest of the body during systole.
Aortic stenosis:
- narrowing of the aortic valve = left ventricle has to generate more pressure to enable sufficient blood to cross the aortic valve and pass into the aorta.
Leads to left ventricular hypertrophy.
Overtime, the left ventricle can no longer compensate and will start to enlarge. Therefore, ejection fraction will reduce and lead to reduced cardiac output.
Causes of aortic stenosis?
- Senile calcification: most common cause in those >65y/o.
- Congenital bicuspid valve: most common cause in those <65y/o.
- Rheumatic heart disease
- William’s syndrome: supravalvular stenosis (congenital heart defect)
Risk factors of aortic stenosis?
- over age 60
- Congenital bicuspid aortic valve
- Rheumatic heart disease
- CKD
Complications of aortic stenosis?
- Left ventricle failure
- Sudden cardiac death
Aortic stenosis symptoms?
- can be asymptomatic
- syncope
- angina
- dyspnoea on exertion
- pre-syncope
- palpitations
- left ventricular heart failure symptoms (exertional dyspnoea, orthopnoea, PND)
- can present in cardiac arrest/sudden cardiac death
Aortic stenosis signs?
Systolic murmur
- heard best on the right 2nd intercostal space
- described ‘harsh’
- radiates to the carotids
- sound is exaggerated with pt sitting forward and their breath held during expiration
Slow-rising carotid pulse
Narrow pulse pressure
Heaving, non-displaced apex beat (displaced if LVH present)
Soft S2 heart sound: absent S2 corresponds with severity.
Ejection click may be heard in some cases (early systolic)
How is aortic stenosis diagnosed?
Echocardiogram (1st line)
- Peak gradient > 40 mmHg (note, in severe left ventricular dysfunction, a low peak gradient can be falsely reassuring)
- Valve area < 1.0cm x2
- Aortic jet velocity >4 m/s
Other investigations for aortic stenosis?
ECG
- left ventricle hypertrophy (LVH) due to pressure overload.
- absent Q waves
- left axis deviation
- poor R wave progression
CXR
- cardiomegaly
- pulmonary oedema
- calcified aortic valve
Exercise testing
- assess true severity of asymptomatic pts that are physically active in addition to echocardiography
Cardiac MRI
- provide details about valve morphology, dimensions of the aortic root, and extent of valve calcification
Management of aortic stenosis?
Conservative:
- regular monitoring via echocardiogram
Medical:
Left ventricular heart failure tx
- ACEi, BB, spironolactone, hydralazine, diuretics
Surgical:
Transcatheter aortic valve implantation (TAVI)
- favoured with patients with severe comorbidities, previous heart surgery, frailty, restricted mobility, and those older than 75 years of age
Surgical aortic valve replacement (SAVR)
- favoured for patients who are low risk and less than 75 years of age.
What is aortic sclerosis?
Refers to an asymptomatic condition where parts of the tricuspid valve is calcified and thickened.
Causes of aortic sclerosis?
age-related senile degeneration of the valve
Signs of aortic sclerosis?
- ejection systolic murmur
- does not radiate to the carotids
- normal S2, pulse character, and volume
What is a heart murmur?
Refers to sound produced when blood flows abnormally through a heart valve.
Whooshing, swishing, blowing sound.
What causes a heart murmur?
Stenosis
Regurgitation
What is stenosis?
Refers to blood flowing through a valve that does not open fully as it is abnormally narrow valve.
What is regurgitation?
Refers to blood flowing backwards through a valve due to inadequate valve closure.
How do you identify heart murmurs?
- Systolic (S1) vs. diastolic (S2)
- Loudest location
- Manoeuvres that exaggerate the murmur
- Murmur radiation