AS (aortic stenosis)

Question 1

Difference between aortic stenosis + sclerosis

Answer 1

Aortic stenosis = outflow obstruction @ aortic valve – usually due to aortic valve stenosis

Aortic sclerosis = aortic valve thickening w.o obstruction

Question 2

Time of progression from Dx of aortic sclerosis to moderate/severe aortic stenosis?

Answer 2

6-8y

Question 3

Major (4) + minor (3) AS risk factors

Answer 3

MAJOR

• age > 60
• bicuspid aortic valve
• rheumatic heart disease
• chronic renal disease

MINOR

• cardiovascular risk factors (smoking, HTN, LDL, diabetes)
• high CRP
• connective tissue disease

Question 4

Pathogenesis of AS development + factors that accelerate development (5)

Answer 4

Turbulent flow across valve –> valve endothelium damaged –> inflammation (similar to atherosclerosis) –> Ca2+ deposition in valve –> progressive valve calcification (sclerosis) –> reduced valve mobility –> ultimately leads to outflow obstruction

Factors accelerating calcification:

• bicuspid valve = turbulent flow
• chronic kidney disease = Ca2+ homeostasis
• rheumatic valve disease = inflammation
• connective tissue disease = reduced vessel/valve integrity
• cardiac risk factors = increased afterload, reduced vessel/valve integrity

Question 5

Pathogenesis of AS disease progression (decompensation)

Answer 5

Aortic stenosis –> increased afterload –> LV hypertropy. Eventually stenosis is so extensive that decompsation occurs –> reduced systolic fx (reduced CO).

LV hypertrophy + increased contractility also leads to increased diastolic pressure (impaired filling) + myocardial ischemia (impaired CA filling, increased metabolic demand). Ischemic tissue is also more prone to produce (ventricular) arrhythmias

Question 6

AS clinical Px – common (H3, E3) + uncommon (H1, E3)

Answer 6

COMMON Hx

1. SOBOE (most common)
2. Ischemic chest pain
3. Syncope

COMMON Ex

1. Pansystolic ejection murmur = loudest over aorta, radiating to carotids, crescendo-decrescendo
2. soft S2
3. soft pulses

UNCOMMON Hx = bleeding (epistaxis + bruising common due to acquired VWB deficiency)

UNCOMMON Ex

1. Split S2 = due to delayed aortic valve closure
2. Slow rising pulse – palpable @ carotids (Carotid parvus et tardus)
3. Gallavardin’ s phenomenon = musical holosytolic murmur mimicing AR heard @ apex in older pts

Question 7

For how long is AS subclinical?

Answer 7

until severe disease

Question 8

Which Ix would you order to Dx AS? What would they show?

Answer 8

1. ECG (>90% SN)
   - LVH (most common)
   - Absent Q waves
   - Conduction block (AV, hemi, BBB)
2. Echo / doppler
   - increased aortic pressure gradient
   - reduced aortic diameter (stenosis)
   - reduced EF%
   - thickened valve
   - reduced leaflet mobility
3. Cardiac catheterisation
   - may be used if inconclusive doppler
   - assesses aortic pressure gradient

Question 9

What Ix would be useful to assess severity / risk stratify?

Answer 9

ECG stress test

• defines symptom onset if +ve
• ST changes
• abnormal BP response
• complex ventricular arrhythmia
• may use dobutamine stress test
• CONTRAINDICATED IN SEVERE AS

Question 10

What are the benefits of a dobutamine stress test over exercise stress test

Answer 10

• more accurate risk stratification pre-op

- assesses contractile reserve

Question 11

Rx for presumptive (2) + acute pts (4) of AS

Answer 11

PRESUMPTIVE

• must be stabilised before surgery / procedures
• Medical Mx = b-blockers/Ca-channel blockers to control afterload – but care to avoid syncope/hypotension. ACEIs + diuretics used w. care for same reason. Control cardiac risk factors - e.g. LDL
• Balloon valvotomy = may be temporising measure until surgery

ACUTE PTS

• Clinical echo (+ follow up)
• Surgical valve replacement = higher risk of ischemic / arrhythmic events
  - mechanical (need LT anticoagulation) / bioprosthetic (need replacement)
  - may be recommended in EF% unknown valve durability
  - same reasoning for mech/bioprosthetic valves
• Balloon valvotomy = symptom control in palliative pts unsuitable for surgery

MONITORING 
- close monitoring via TOE 
	• Mild = 3-5y
	• Moderate = 1-2y
	• Severe = 6-12mo

Question 12

Possible Cx (6) of AS

Answer 12

1. Acute CCF = (long-term) Rx vasodilators/diuretics –> valve replacement
2. Sudden cardiac death = if symptomatic (vent. arrhythm)
3. Infective endocardititis = esp. replaced valves
4. Thrombosis = turbulent mechanical valves
5. Re-stenosis = should be considered in return to pre-op symptoms > 10y after valve replacement
6. Valve dehiscience

Question 13

DDX (3)

Answer 13

• aortic sclerosis
• IHD
• HOCM (outflow obstruction)