• classification is MEAN pressure gradient
• main problem = FIXED STROKE VOLUME due to LVH
• priorities = optimal LV filling
• HD goals
  • Maintain myocardial O2 delivery

• Aortic valve stenosis
• Obstruction of blood flow across the AV

• MPG = mean peak gradient
  • severe > 40 mmHg
  • critical > 80 mmHg
• AVA = aortic valve area
  • severe < 1.0 cm2
  • critical < 0.5 cm2
• Indexed AVA cm2/m2
  • severe < 0.6 cm2/m2
• Pvel = peak velocity

• Overview
  • most common VHD in Europe/USA
• Incidence
  • 2-7% of 65+
• Prevalence
• Gender
  • males 4x

• often latent period of 30 years
• progression = recent change
• ⬆30/7 mortality 2.1% (cf 1.0%)
  • ⬆risk MACE
    • high-risk surgery
    • severe + symptomatic
    • coexisting MR (mod/sev)
    • pre-existing CAD
• acquired vWF
  • degradation of vWF across aortic valve
  • high shear forces ⮕ structural changes
  • result = platelet dysfunction

1. Calcific (degenerative) = 80% (most common)

• degenerative condition = inflammation and progressive calcification, limiting movement of AV
• RF: elderly (65+), HChol, HT, smoking, DM

2. Calcific Bicuspid valve (congenital)

• frequency 1-2%
• most common congenital abnormality of the heart
• RF: male
• There can be MIXED disease in bicuspid AV
• abnormal valve -> ⬆turbulent flow -> ⬆fibrosis + calcification

3. Rheumatic heart disease

• autoimmune condition, following Streptococcal (Group A) infection

• molecular mimicry -> inflammation

• tissues affected: heart, joints, CNS

• less common now

• NB. concomitant mitral valve disease

• Rare

• Metabolic, eg. Fabry's disease (lysosomal storage disease)

• end result of inflammatory process

• endothelial damage

  • mechanical stress
  • lipid accumulation
  • fibrosis

• leaflet thickening

• leaflet calcification

• AS

• ⬆AL on LV

• ⬆wall tension required

• ⬆pressure gradient, ⬆wall tension

  • ⬆difference between LV and Aortic root to maintain SV
  • turbulent flow = ejection systolic murmur

• 1: latent phase

  • abnormal valve, LVOTO

• 2: compensatory phase

  • LVH to overcome LVOTO and maintain EF
  • ⬆CMRO2, ⬇supply, diastolic dysfunction

• 3: Decompensation

  • ⬆LVH, ⬇EF
  • pulmonary oedema, MR

• 4: Symptomatic phase

  • narrower valve = ⬇AVA = ⬆kinetic energy, but ⬇pressure
  • result = ⬇perfusion pressure of coronary As
  • Dyspnoea, Exertional syncope, Angina

• initial = systolic failure / dysfunction

  • LV unable to maintain SV (normal proportion of EDV) = ⬇EF%
  • compensation
    • concentric LVH
    • ⬆INO = sustained apex beat
  • cost
    • ⬇ventricular compliance = diastolic failure
    • ⬆MVO2 (⬆myocardial tissue)

• later

  • ⬆LVEDP ⮕ ⬇coronary BQ, ⬆myocardial ischaemia (subendocardial)

• late = LV systolic failure

  • ⬇INO, LV dilatation ⮕ ⬇⬇CO = acute decompensation

• both lead to CCF, with SOB and bibasal crackles

• NB. Pressure-volume loop for AS

  • loop is shifted up and right

• Classic triad = DEA

  • dyspnoea 50% = 1st symptom
  • exertional syncope = 35%
  • angina 15%

• symptomatic

  • ⬇ability to adjust to myocardial demand
  • exhausation of compensatory mechanisms
  • prone to EXERTIONAL symptoms (SOB, syncope)

• angina

  • ⬇coronary BQ
  • ⬆O2 demand (LVH, ⬆myocardial mass)
  • may not have CAD = a MISMATCH between supply and demand
  • CAD 50%

• dyspnoea

• multifactorial

• LVH / diastolic dysfunction, ⬆LVEDP

• syncope

• inadequate CO

• ⬇SV with ⬆HR

• vasoD with exercise

• epistaxis/bruising

Main

• ESM radiating to carotids
• sustained apex beat / heaving apex
• slow rising pulse
• "parvus et tardus" carotid pulse
  • parvus = small volume
  • tardus = delayed
• narrow pulse pressure
  • ⬆DBP (⬆EDV), eg. 130/110
• may radiate to apex = Gallavardin phenomenon
  • but doesn't radiate to left axilla (MR does)
• thrill = palpable murmur
  • severe AS

Others

• Soft S2 (soft A2)
  • marker of severity
  • Aortic component of S2 quieter as valve leaflets fail to oppose forcefully
• S3
• S4 (4th heart sound)
  • atria contracting against stiff, hypertrophied ventricles
• Reversed splitting

• Echo = TTE/TOE
  • valve = peak flow, AVA, AR
  • consequences = LV, LA, MV, post-stenotic aortic dilatation
• ECG
  • LVH
  • LV strain (severe)
  • LA deviation
• Left heart catheter study
  • retrograde catheterisation of aortic valve = assess PG
• Cardiac MRI
  • assess consequences of stenosis
• CXR
  • Cardiomegaly
  • LVF
  • calcification

• no medical management
• valve replacement
  • percutanous = TAVI = transcatheter AV implantation
    • minimally invasive
    • for patients not suitable for open procedure
  • open = AVR
  • for severe AS / symptomatic
• valvotomy
  • percutaneous balloon aortic valvuloplasty (BAV)
  • TAVI
    • newer generation = allow percutaneous valve insertion = valve-in-valve = Inspiris
    • if future restenosis
  • open valvotomy
• coronary angiogram
  • determine if CABG required at same time

• Pre-op
  • severe
    • asymptomatic
      • reasonable to proceed to surgery
      • appropriate intraop and postop monitoring ***
• Intra-op
  • 1:preload
    • avoid hypovolaemia ⮕ ⬇CO
    • must have adequate SV
    • "full"
    • guided by CO monitoring
  • 2:rate
    • aim rate 50-60
    • avoid tachycardia ⮕ ⬇⬇LV filling ⮕ ⬇CO
      • ⬇time for coronary filling
      • ⬆MRO2 and ischaemia
    • avoid bradyC = limit of SV = APO
    • LV has fixed SV (⬇compliance) = unable to ⬆filling with ⬇HR
  • 3:rhythm
    • maintain SINUS rhythm
    • atrial contraction contributes 40% filling in stiff hypertrophied LV ⮕ ⬇CO
    • avoid arrhythmias ⮕ ⬇LV filling
    • cardioversion if HDI with arrhythmia
  • 4:contractility
    • already hyper-contractile
    • do not give negative inotropes (BB, CBB)
  • 5:afterload
    • maintain AL for coronary perfusion *** = "tight"
      • coronary A perfusion is dependent on aortic root pressure
      • prevent vasoD / venoD
      • avoid ⬇SVR / ⬇DBP ⮕ ⬇coronary BQ
        • ⬇SVR does NOT ⬇AL (AS is fixed)
      • ⬆DBP required for CPP because of ⬆LVEDP
      • caution with neuraxial blockade
  • decompensation
    • VASOPRESSORS are key intervention (not inotropes)
• Post-op

• classification of AS severity (AVA, TVPG)
• NYHA classification of perioperative risk: should surgery be cancelled?
• treatment: when is surgery indicated?
• options of anaesthesia (non-cardiac surgery)
• antibiotic prophylaxis
• central neuraxial blockade and AS
• haemodynamic goals during non-cardiac surgery (and how to achieve)
• role for invasive monitoring
  • problems with PA caths?
• cardiac arrest: priorities?
• ventricular Pressure/Volume relationship in AS

https://www.escardio.org/Journals/E-Journal-of-Cardiology-Practice/Volume-15/Aortic-valve-stenosis-evaluation-and-management-of-patients-with-discordant-grading

Final FRCA In A Box

https://derangedphysiology.com/main/required-reading/cardiothoracic-intensive-care/Chapter%202.1.3/aortic-stenosis

https://www.escardio.org/Journals/E-Journal-of-Cardiology-Practice/Volume-18/physical-examination-in-aortic-valve-disease-do-we-still-need-it-in-the-modern