Hello and welcome to the zero to finals podcast.

My name is Tom and in this episode I'm going to be talking to you about prosthetic heart valves.

And if you want to follow along with written notes on this topic,

you can follow along at zero to finals.com slash prosthetic valves or in the cardiology section of the zero to finals medicine book. So let's get straight into it.

Prothetic heart valves are used to replace the patient's own heart valve when there's disease

affecting that valve. Patients that have had a valve replaced will have a scar. Usually this will be a

midline stenotomy

scar which is straight down the middle of the sternum indicating a mitral or aortic valve replacement.

But this type of scar can also indicate there's a coronary artery bypass graft or a cabbage procedure

that's taken place.

Less commonly, a right-sided mini-thorocotomy incision can be used for minimally invasive mitral valve replacement surgery.

There's a key distinguishing feature between the two types of prosthetic heart valves, and

they are bioprostetic and mechanical heart valves.

Valves can either be replaced by a bioprostatic or a metallic mechanical valve.

Porcine, bioprothetic valves come from a pig. Bioprothetic valves have a limited lifespan of around 10 years, whereas

mechanical valves have a good lifespan well over 20 years, however they require lifelong

anticoagulation with warfarin. The INR target range for mechanical valves is typically 2.5 to 3.5,

and this is higher than the normal 2 to 3 range

that you would find in conditions such as atrial fibrillation. Let's talk about some of the types

of mechanical heart valves. Firstly, there's the Star Edwards valve, and this is a ball inside a cage,

and it's very successful, but it's no longer being used, and this is a ball inside a cage and it's very successful but it's no longer being used

and this is because it's the highest risk valve for thrombus formation. So patients will typically

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