Aortic Stenosis Flashcards

1
Q

Presentation of aortic stenosis

A

Diagnosis: aortic stenosis (+/- severe)
1. Ejection systolic crescendo-decresendo murmur best heard over aortic, grade __, radiating to the carotids
(+/- Gallavardin phenomenon mitral)
2. Thrills over aortic area
3. Apex beat is heaving but undisplaced

Severity and complications:
1. Slow rising, low volume pulse
2. Narrow pulse pressure (if checked)
3. Infective endocarditis - peripheral stigmata
4. Left heart failure -S4, pulmonary oedema
5. Pulmonary hypertension - elevated JVP, giant V wave, TR, pedal oedema, parasternal heave

Ending
1. Vital signs - blood pressure, heart rate
2. Electrocardiogram

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2
Q

What are the causes of aortic stenosis?
(min 3, max 8)
- M: RBD PICO

A
  1. Rheumatic heart disease (< 60 years old)
  2. Bicuspid valve (60-75 years old, males)
  3. Degenerative calcification (commonest in elderly)
  4. Paget’s disease
  5. Infective endocarditis
  6. Congenital (William, rarely Noonan)
  7. Others - hyperuricaemia, alkaptonuria (very rare)
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3
Q

Differential diagnosis of ejection systolic murmur? (6)
How to differentiate between them?

A
  1. Aortic stenosis and variants
    - Supravalvular AS
  2. Pulmonary stenosis
  3. HOCM (subvalvular AS)
  4. Aortic sclerosis
  5. MVP/MR
  6. 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

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4
Q

How do you classify the severity of aortic stenosis?
- Clinical symptoms (M: ASD)
- TTE

A

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

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5
Q

What are the signs/examination findings of aortic stenosis? (9)
* denotes severe

A

*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
7A. Possible Gallavardin phenomenon (ESM loudest at mitral)
*8. Evidence of heart failure
*9. Evidence of pulmonary hypertension - giant V wave, TR, parasternal heave, loud P2

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6
Q

Describe this heart sound

A

S1, with ejection systolic crescendo-decrescendo murmur, absent of S2
Diagnosis: aortic stenosis

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7
Q

What are the complications of aortic stenosis? (7)

A
  1. Left ventricular failure
  2. Pulmonary hypertension
  3. Arrhythmia (AF, VT) and heart block (calcification of conduction system)
  4. Infective endocarditis
  5. Thromboembolism
  6. Anaemia
    - Haemolytic: severe calcified aortic valve
    - Iron deficiency: chronic disease or Heyde’s syndrome
  7. Sudden death
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8
Q

How would you manage an asymptomatic patient with aortic stenosis?

A
  1. Endocarditis prophylaxis (good dentition)
  2. Report symptoms of angina, palpitations, syncope, breathlessness
  3. Screening TTE and for valve replacement if symptoms develop or TTE gradient > 50mmHg or valve area < 0.8cm
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9
Q

How would you investigate a patient with aortic stenosis?
- ECG (3)
- CXR (5)
- TTE (2)
- Angiogram

A
  1. 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
  2. CXR
    - Rib notching
    - Dilated ascending aorta (post-stenotic dilatation)
    - Calcified aortic valve
    - Cardiomegaly
    - Pulmonary congestion, dilated pulmonary arteries (hypertension)
  3. TTE
    - Aortic valve area (severity)
    - Left ventricular size and function
    - Assess complications (IE)
  4. Coronary angiography
    - Look for concurrent coronary artery disease, for concomittant CABG + valve replacement
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10
Q

What are the indications for aortic valve replacement in the context of aortic stenosis?
- Symptomatic, asymptomatic

A
  1. Symptomatic severe aortic stenosis (gradient > 50mmHg)
  2. 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)

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11
Q

What are the types of pulses associated with AS?

A
  1. Pulsus parvus et tardus - low volume pulse with delayed upstroke (from reduction in systolic pressure and gradual decline in diastolic pressure)
  2. Anacrotic pulse - small volume pulse with notch on upstroke
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12
Q

How does second heart sound changes with severity of AS?

A

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

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13
Q

What is Gallavardin phenomenon?

A

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)
3. Crescendo-decresendo murmur

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14
Q

How do you differentiate AS from HOCM?

A

AS
Carotid pulse: slow rising
Thrill over aortic area
ESM

HOCM
Carotid pulse: bifid, jerky
Thrill over LLSE
Rarely ESM

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15
Q

How do you differentiate aortic stenosis from aortic sclerosis?

A

Aortic sclerosis
- No severity signs
- Apex beat undisplaced, no heaving
- Normal S2 (not diminished)
- ESM localised to aortic area without radiation

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16
Q

What are the symptoms associated with severity of AS and the pathophysiology behind them?

A
  1. 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
  2. Syncope - 3 year prognosis
    - Low cardiac output state, peripheral vasodilatation, drop in preload without concomittant increase in CO
    - Cardiac arrhythmias (AF, VT)
    - Transient electromechanical dissociation (Conducted but LV unable to contract against stenosed valve)
    - Erroneously prescribed vasodilator drugs nitrates (CI in AS)
  3. Dyspnoea - 2 year prognosis
    - LV dysfunction and heart failure
17
Q

What are the surgical options for AS?

A
  1. Valve replacement (surgery of choice)
  2. Valvuloplasty (for moribund patients)
18
Q

What are your thoughts about a young person with AS murmur but normal aortic valve?

A
  1. Subvalvular stenosis in HOCM
  2. Supravalvular stenosis
    - Isolated
    - A/w Williams’ syndrome: Chromosome 7 autosomal dominant.
    - Features: Elfin facies, hypertension, mental restriction, hypercalcaemia, other cardiac lesions like PS, MR
19
Q

What abdominal condition is associated with AS?

A

Angiodysplasia of colon (Heyde’s syndrome)
- Possible acquired defect in von Willebrand factor (type 2A) due to high shear forces causing proteolysis as blood passes through stenotic AV

20
Q

What is pulse pressure?

A

No formal definition - difference between systolic and diastolic pressure

Normal: 40mmHg
Wide: > 60mmHg
Narrow: < 25mmHg

21
Q

What are the advantages of TAVI over open heart surgery?

A

Open heart surgery remains gold standard

TAVI is good for patients with higher pre-operative risks and multiple co-morbidities

22
Q

When might a balloon valvuloplasty be performed for aortic stenosis?

A

Usually a temporary measure pre definitive surgical management

If a patient has cardiogenic shock or unstable angina

23
Q

Can apex beat be displaced in severe AS?

A
Yes, in late stage severe AS where left ventricular hypertrophy and dilatation develops

Apex beat in AS is usually heaving and undisplaced/minimally displaced.

If apex beat is displaced but absent of severe AS signs -> think of other causes

24
Q

What is aortic sclerosis

A

Mild thickening or calcification of trileaflet aortic valve with absent of outflow obstruction.

It is progressive over time with increased calcification and thickening leading to aortic stenosis.
(1/3 develop over 4 years)

Also associated with 50% increased in cardiovascular mortality and MI, possible novel marker for silent CAD

25
Q

What are the causes of reversed splitting of S2?

A
  1. Aortic stenosis
  2. LBBB
  3. PDA
  4. WPW type B