Aortic stenosis

Station 3: Cardiology examination

 

Likely vignette: "This person has presented with chest pain / breathlessness / collapse"

Examination features:

  • Pulse:

    • Slow-rising pulse – weaker and later compared to normal pulse

    • Imagine a pulse rolling across your fingers, rather than a discrete pulsation​

  • Eyes:

    • Anaemia – conjunctival pallor, possible manifestation of angiodysplasia or haemolysis (rare in native heart valves, more common in prosthetic valves)

  • Neck:

    • Check JVP, if raised suggestive of decompensation

  • Precordium:

    • Ejection systolic murmur

      • Typically crescendo-decrescendo in nature 

      • Loudest over the aortic area and in held expiration

      • Radiates to the carotids, but may be heard elsewhere

      • Is S2 well heard? If not, this is a sign of severity

      • May be associated with a palpable thrill

  • Lung bases:

    • Bibasal crepitations suggestive of decompensation of heart failure

  • Legs: 

    • Pitting oedema suggestive of decompensated heart failure

Differential diagnosis for a systolic murmur

  • Aortic sclerosis - softer murmur, typically does not radiate

  • Mitral regurgitation - pansystolic, best heard at the apex, radiates to axilla

  • Ventricular septal defect - loud pansystolic murmur, best heard at left lower sternal edge

  • Hypertrophic cardiomyopathy - ejection systolic murmur, best heard at left lower sternal edge, likely to be a young patient

  • Pulmonary stenosis - rare, likely to be a younger patient with congenital aetiology

Key tip

Consistency is key. If you can tell that the murmur is ejection systolic, then you will be able to present a more concise list of differential diagnoses. If you are unsure but know that is is a systolic murmur, give differentials for a systolic murmur but justify why it’s unlikely to be something else.

Aetiology of aortic stenosis:

  • 80% degenerative calcification – aged 70-85yrs

  • 5-10% Congenital bicuspid valve – 40-60yrs

  • Rheumatic fever (rare)

 

Investigations: 

  • Bedside:

    • 12-lead ECG: 

      • LV hypertrophy due to AS

      • Conduction defects e.g. LBBB or any degree of heart (AVN) block

        • 10% of patients go onto have a pacemaker post-TAVI
        • This is due to the proximity of the aortic valve annulus to the AV node during deployment of the valve
  • Bloods:

    • Routine blood tests – FBC, U&Es, LFTs, coagulation

      • These may affect what drugs are given post-operatively and for long-term management

      • Not usually critical to diagnosis

 

  • Imaging:

    • Echocardiogram to:

      • Qualify diagnosis:

        • Calcified cusps

        • Restricted opening of valve leaflets

        • Bicuspid valve

      • Quantify severity:

        • Peak gradient >64mmHg or mean gradient >40mmHg

        • Dimensionless index: ratio of blood flow velocity across aortic valve to velocity in LVOT, severe is <0.25 

        • Valve area is still relevant, <1cm classed as severe

      • LV function assessment

    • CXR: any evidence of pulmonary oedema, cardiomegaly or other signs of heart failure

 

  • Special tests:

    • Gated CT TAVI – to measure valve annulus size (so they can choose the correctly sized valve), and assess suitability of peripheral vascular access

    • Lung function tests – often done pre-operatively if the patient is a current or previous smoker

    • Coronary angiogram – it is often possible to perform CABG surgery at the time of valve replacement

    • Carotid doppler – no longer routine but may be asked for by cardiothoracic surgeons if high risk for stroke

Management:

Dr Dorman's view: 

  • >75yrs – default management should be TAVI unless not technically favourable

  • <75yrs – default should be surgical aortic valve replacement

There are no evidence-based drug options that prevent or treat aortic stenosis

Common examiner questions

What are the pros and cons of TAVI versus surgical AV

What are the complications of untreated aortic stenosis?

  • Heart failure 

  • Brady / tachyarrhythmias

  • Injury from falls following syncope

  • Anaemia due to haemolysis, angiodysplasia or Heyde’s syndrome

What are the most significant complications of TAVI?

  • Pacemaker (10%)

  • Vascular access complications (5%)

  • Stroke, MI, blockage of coronary artery, annular rupture, apex perforation (2%)