Valvular Diseases Overview

 

• Definition

  • Stenosis (can't open fully) or regurgitation (can't close fully, aka incompetence).
  • Can affect any valve, but most commonly left sided and systolic (atrial stenosis, mitral regurgitation).
  • Diseased valve can have mixed features i.e. regurgitation and stenosis.

• Signs and symptoms

  • Murmur.
  • ↓Cardiac output → fatigue.
  • ↑Diastolic pressure → pulmonary or peripheral oedema.
  • ↑Wall tension → angina.

• Investigations

  Initial tests

  Echocardiography:

  • Diagnostic test and determines severity.
  • Either transthoracic or transoesophageal, with doppler.
  • Looks at valve diameter, valve anatomy (leaflets, calcification), jet velocity, and pressure gradient across valve.

  ECG and CXR:

  • Identify co-morbid ischaemia, LVF, and AF.

  Further tests

  • Cardiac MRI if echo unclear.
  • Coronary angiography is usually done to check for associated IHD if surgery is planned. May lead to combined CABG plus valve surgery.
  • Cardiac catheterisation is added to angiography if the echo is inconclusive. Unlike angiography, this involves passing pressure probes into the chambers of the heart, allowing haemodynamic measurements, and may also involve aortography and/or ventricular angiography. Risk of releasing emboli.
  • Stress echo or ECG may be done if symptoms are exertional.
  • There may be a role for BNP as a prognostic marker, but its exact nature hasn't yet been determined.

• Management

  Medical management of cardiac risk factors and complications/co-morbidities:

  • LVF: ACEi, β-blocker, and spironolactone.
  • AF: usually warfarin, as novel oral anticoagulants have not been trialled in valvular AF.

  Endocarditis prevention:

  • Good oral hygiene, good aseptic technique in medical procedures.
  • Antibiotic prophylaxis limited to high-risk procedures in patients with prosthetic valves or congenital disease.

  Serial testing:

  • Regular echo, every 6-12 months if severe, every 2 years if mild-moderate.

  Surgery:

  • In general, severe symptomatic valve disease requires surgery, provided the patient is fit and has at least 1 year of predicted life expectancy post-op.
  • May involve repair or replacement of faulty valve.
  • If 2 valves are diseased, often makes sense to do both in same procedure.
  • Mechanical valves are more durable so used in younger patients, but carry a higher risk of thrombus formation so require lifelong anticoagulation. Higher INR target than AF: 3.0 (aortic) or 3.5 (mitral). Consider adding aspirin if there is concomitant atherosclerosis or thromboembolism despite optimal INR.
  • Bioprosthetic valves are less durable, and usually only used if age >65. Follow up with 3 months of anticoagulation after mitral surgery, or 3 months aspirin if aortic. Normal INR target (2.5). Aspirin after 3 months only if there is another indication e.g. IHD.
  • Follow up with regular echo.