Prosthetic Valves

This is a common case in PACES. Patients often have either an aortic or mitral valve replacement and often both. The replacement valves can be metallic or tissue valves.

 

Metallic valves last longer than tissue valves but require anticoagulation (usually with warfarin) or will throw off emboli.

Tissue valves usually last around 10 years and are preferred in patients you do not want to anticoagulate, mainly patients wanting to pregnant, or those in who anticoagulation bears significant risk.

 

Signs:

  • Median sternotomy scar
  • Look for signs of endocarditis
  • Look for vein harvesting in the legs suggestive of CABG performed at the time of valve replacement.
  • Bruising from warfarinisation (suggesting metallic valve)
  • Anaemia or jaundice from mechanical haemolysis of red cells (rare)

 

Valvular sounds:

  • Time the sounds with the carotid pulse. Remember that the 1st heart sound is closure of the mitral valve and 2nd heart sound closure of the aortic valve. So a metallic click just before the carotid pulse is a mitral valve replacement and just after the carotid pulse is an aortic valve replacement.

 

  • When patients have both valves replaced you will hear a click both before and after the valve. This can initially be confusing the aortic metallic valve click will be heard louder over the aortic area and the mitral metallic valve louder over the mitral area so if unsure listen over both areas intently listening for a change in the intensity of the click.

 

  • Tissue valves don’t have a metallic click! But have a timbre different from normal heart valves; often lower pitched. A quiet flow murmur across an aortic tissue valve is normal (as they rarely fit perfectly), but a regurgitant murmur is not and usually represents a paravalvular leak or valve failure. Mitral tissue valves shouldn’t normally have a flow murmur.

 

  • Mechanical valves give a mechanical click with the closing of the valve. Patients with a ball and cage Starr-Edwards aortic valve may have numerous audible sounds.

 

Questions will often regard complications or the differences between tissue valves.

 

Complications:

  • Valvular failure
  • Valve thrombosis
  • Acute valvular dehiscence
  • Acute endocarditis (post-op)
  • Subacute IE
  • CVA/TIA (Embolic phenomena)
  • Haemolysis
  • Bleeding from warfarin

 

 

Written by Dr Thomas Craven

 

Resources used to write this document are listed in the references section of this webpage