Patients that have had a valve replacement will have a scar. Usually this will be a midline sternotomy scar straight down the middle of the sternum indicating a mitral or aortic valve replacement or CABG). Less commonly a right sided mini-thoracotomy incision can be used for minimally invasive mitral valve replacement surgery.
Bioprosthetic versus mechanical
Valves can be either replaced by a bioprosthetic or a metallic mechanical valve. “Porcine” bioprosthetic valves come from a pig.
Bioprosthetic valves have a limited lifespan of around 10 years.
Mechanical valves have a good lifespan (well over 20 years) but require lifelong anticoagulation with warfarin. The INR target range with mechanical valves is 2.5 – 3.5.
Types of Mechanic Heart Valves
- Ball in cage valve
- Very successful but no longer being implanted
- Highest risk of thrombus formation
Tilting disc valve
- A single tilting disc
St Jude Valve
- Two tilting metal discs
- The two discs mean they are called bileaflet valve
- Least risk of thrombus formation
Mechanical Heart Valves
- Thrombus formation (blood stagnates and clots)
- Infective endocarditis (infection in prosthesis)
- Haemolysis causing anaemia (blood gets churned up in the valve)
Mechanical valves cause a click
- A click replaces S1 for metallic mitral valve
- A click replaces S2 for metallic aortic valve
Transcatheter Aortic Valve Implantation (TAVI)
This is a treatment for severe aortic stenosis, usually in patients that are high risk for an open valve replacement operation. It involves local or general anaesthetic, inserting a catheter in to the femoral artery, feeding a wire under xray guidance to the location of their aortic valve, then inflating a balloon to stretch the stenosed aortic valve and implanting a bioprosthetic valve in the location of the aortic valve.
Long term outcomes for TAVI are still not clear as it is a relatively new procedure. Therefore in younger, fitter patients open surgery is still the first line option.
Patient that have a TAVI do not typically require warfarin as the valve is bioprosthetic.
This occurs in around 2.5% of patients having a surgical valve replacement. The rate is slightly lower for TAVI at around 1.5%. Infective endocarditis in a prosthetic valve has quite a high mortality of around 15%. This is usually caused by one of three gram positive cocci organisms:
Last updated November 2018