Aortic Stenosis Flashcards
What are the causes of aortic stenosis?
(min 3, max 8)
- M: RBD PICO
- Rheumatic heart disease (< 60 years old)
- Bicuspid valve (60-75 years old, males)
- Degenerative calcification (commonest in elderly)
- Paget’s disease
- Infective endocarditis
- Congenital (William, rarely Noonan)
- Others - hyperuricaemia, alkaptonuria (very rare)
Differential diagnosis of ejection systolic murmur? (6)
How to differentiate between them?
- Aortic stenosis and variants
- Supravalvular AS - Pulmonary stenosis
- HOCM (subvalvular AS)
- Aortic sclerosis
- MVP/MR
- Coarctation of aorta
AS vs PS - expiration at aortic vs inspiration at pulmonary
AS vs HOCM - Valsalva, squatting
AS vs MVP - location, clicks
AS vs coarctation - differential pulse
How do you classify the severity of aortic stenosis?
- Clinical symptoms (M: ASD)
- TTE
Clinical
Angina: 5 years
Syncope: 3 years
Dyspnoea: 2 years
TTE
A. By valve area:
- Normal 3-4cm
- Mild > 1.5
- Moderate 1-1.5
- Severe < 1
- Critical: < 0.7 (or 0.6)
B. By gradient: Gorlin formula
- Mild: < 25mmHg
- Moderate: 25-50mmHg
- Severe: 50-80mmHg
- Critical: > 80mmHg
peak > 64mmHg, average > 40mmHg
What are the signs/examination findings of aortic stenosis? (9)
* denotes severe
*1. Narrow pulse pressure
*2. Slow rising, low volume pulse (do not comment if AF)
3. Systolic thrill over aortic region
4. Heaving undisplaced apex (LVH)
5. Quiet or absent aortic component of S2, reversed splitting of S2
*6. S4 (left heart failure)
7. Delayed ejection systolic murmur *(long ESM), loudest on expiration and radiating to carotids
*8. Evidence of heart failure
*9. Evidence of pulmonary hypertension - giant V wave, TR, parasternal heave, loud P2
What are the complications of aortic stenosis? (7)
- Left ventricular failure
- Pulmonary hypertension
- Arrhythmia (AF, VT) and heart block (calcification of conduction system)
- Infective endocarditis
- Thromboembolism
- Anaemia
- Haemolytic: severe calcified aortic valve
- Iron deficiency: chronic disease or Heyde’s syndrome - Sudden death
How would you manage an asymptomatic patient with aortic stenosis?
- Endocarditis prophylaxis (good dentition)
- Report symptoms of angina, palpitations, syncope, breathlessness
- Screening TTE and for valve replacement if symptoms develop or TTE gradient > 50mmHg or valve area < 0.8cm
How would you investigate a patient with aortic stenosis?
- ECG (3)
- CXR (5)
- TTE (2)
- Angiogram
- ECG
- left ventricular hypertrophy/strain: ST-d, TWI, SV1+RV5
- Left atrial dilatation (P mitrale: bifid or inverted P in V1-V2)
- Conduction abnormalities: LBBB, first degree heart block - CXR
- Rib notching
- Dilated ascending aorta (post-stenotic dilatation)
- Calcified aortic valve
- Cardiomegaly
- Pulmonary congestion, dilated pulmonary arteries (hypertension) - TTE
- Aortic valve area (severity)
- Left ventricular size and function
- Assess complications (IE) - Coronary angiography
- Look for concurrent coronary artery disease, for concomittant CABG + valve replacement
What are the indications for aortic valve replacement in the context of aortic stenosis?
- Symptomatic, asymptomatic
- Symptomatic severe aortic stenosis (gradient > 50mmHg)
- Asymptomatic but with:
A. Mod to severe undergoing other cardiac surgery
B. Severe AS (by gradient/area) with any of:
> LV hypertrophy (LVH > 15mm) or systolic dysfunction (gradient > 40)
> Abnormal BP response (hypotension) to exercise
> Ventricular tachycardia
> Valve area < 0.6 (critical)
What are the types of pulses associated with AS?
- Pulsus parvus et tardus - low volume pulse with delayed upstroke (from reduction in systolic pressure and gradual decline in diastolic pressure)
- Anacrotic pulse - small volume pulse with notch on upstroke
How does second heart sound changes with severity of AS?
S2: closure of aortic valve first then pulmonary valve
Normal - insignificant stenosis
Soft S2 - poorly mobile and stenotic valve
(caveat: usually unable to differentiate A2 and P2, and often we hear loud S2 (which is P2 signifying PHT)
Reverse splitting - mechanical or electrical prolongation of ventricular systole, aortic valve closes later than pulmonary valve
Single S2 - fibrosis and fusion of leaflets
S4 - heart failure
What is Gallavardin phenomenon?
Systolic murmur radiating towards apex
Especially in elderly with calcified valves
Confused with MR murmur
(Murmur loudest over mitral instead of aortic)
How to differentiate Gallavardin AS vs MR murmur
1. Premature atrial contractions - long RR interval, there is accentuation of AS murmur with more blood flow
2. Presence of AR, concurrent high-pitched decrescendo EDM (mixed aortic valve disease)
How do you differentiate AS from HOCM?
AS
Carotid pulse: slow rising
Thrill over aortic area
ESM
HOCM
Carotid pulse: bifid, jerky
Thrill over LLSE
Rarely ESM
How do you differentiate aortic stenosis from aortic sclerosis?
Aortic sclerosis
- No severity signs
- Apex beat undisplaced, no heaving
- Normal S2 (not diminished)
- ESM localised to aortic area without radiation
What are the symptoms associated with severity of AS and the pathophysiology behind them?
- Angina - 5 year prognosis
- Progressive pressure overload with LV maladaptive hypertrophy to counter outflow obstruction
- Increase oxygen requirement for LVH with hypoperfusion of subendocardial myocardium - Syncope - 3 year prognosis
- Low cardiac output state, peripheral vasodilatation without concomittant increase in CO
- Cardiac arrhythmias (AF, VT)
- Transient electromechanical dissociation (LV unable to contract against stenosed valve)
- Erroneously prescribed vasodilator drugs (CI in AS) - Dyspnoea - 2 year prognosis
- LV dysfunction and heart failure
What are the surgical options for AS?
- Valve replacement (surgery of choice)
- Valvuloplasty (for moribund patients)
