Aortic Stenosis

aortic-stenosis

Causes:                                       

[A] Infants, children, adolescents:

  1. Congenital aortic stenosis.
  2. Congenital subvalvular aortic stenosis.
  3. Congenital supravalvular aortic stenosis.

[B] Young adults to middle aged:

  1. Calcification & fibrosis of cong, bicuspid aortic valve.
  2. Rheumatic aortic stenosis.

[C] Middle aged to elderly:

  1. Senile degenerative aortic stenosis.
  2. Calcification of bicuspid valve.
  3. Rheumatic aortic stenosis.

Pathophysiology: In aortic stenosis left ventricle outflow is obstructed, so increased left ventricular pressure causes LVH. In turn this results in relative ischaemia and LVF. Symptoms usually develop when the size of aortic orifice is reduced by 75%.

Clinical features:

Symptoms:

  1. Asymptomatic (mild or moderate aortic stenosis)
  2. Exertional dyspnoea due to LVF.
  3. Angina.
  4. Exertional syncope.
  5. Sudden death.
  6. Episodes of acute pulmonary oedema.

Signs:

  1. Pulse: Slow rising carotid pulse.
  2. Blood pressure:
  • Low systolic pressure.
  • High diastolic pressure.
  • Narrow pulse pressure.
  1. Precordium:
  • Apex beat shifted downwards & outwards.
  • Thrusting left ventricle.
  • Ejection systolic murmur.
  • Signs of LVH.
  • Signs of LVF, e.g.

-Bilateral basal crepitations.

-Pulmonary oedema.

Investigations:

  1. ECG:
  • Left ventricular hypertrophy (usually)
  • Left bundle branch block (LBBB).
  1. Chest X-ray:
  • May be normal, sometimes enlarged left ventricle.
  • Dilated ascending aorta on P/A view.
  • Calcified valve on lateral view.
  1. Echo:
  • Calcified valve with restricted opening.
  • Hypertrophied left ventricle.
  1. Doppler:
  • Measurement of severity of stenosis.
  • Detection of associated aortic regurgitation.
  1. Cardiac catheterization (if coronary disease present):
  • Systolic gradient between LV & aorta.
  • Post-stenotic dilatation of aorta.
  • Regurgitation of aortic valve may be present.

Management:

[A] Medical treatment: In asymptomatic patients conservative management may be appropriate:

  • Angina: β-blockers (not GTN or isosorbide dinitrate)
  • LVF: Diuretics.
  • Antibiotic prophylaxis against infective endocarditis.

Indication for surgery arises when patient develops angina symptoms of low cardiac output or heart failure.

[B] Surgical treatment (valve gradient > 50 mm hg)

  • Aortic balloon valvuloplasty (palliative treatment)
  • Aortic valve replacement (specific treatment)

Reference:

  1. Davidson’s Principles and Practice of Medicine, 21st edition
  2. Wikipedia the free encyclopedia.

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