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

Balloon valvuloplasty can be used as a palliative measure for symptom control 

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%)