When was the first prosthetic valve replacement performed?

1960

What are the causes in which native valves are replaced?

Stenosis, regurgitation, or infection

True/False- All prosthetic valves maintain orifice size of the native valve.

False- are considered to be a man made stenosis

What kinds of complications can be seen with prosthetic valves?

Systemic embolization, perivalvular leaks, degeneration/dehiscence, ring abscess, thrombus formation, endocarditis, & hemolysis

Can prosthetic valves be heard?

Yes 

What kind of sound is heard and what type of prosthetic valve will make the sound?

Valve/poppet “click” heard & mechanical valve

How does a prosthetic valve appear on echo when it becomes dehisced?

Dehisced valves will “rock” relative to the attachment.

On m-mode, which prosthetic valve replacement will appear like m-mode of mitral stenosis?

M-mode of an aortic valve replacement

True/ False- Prosthetic valves are considered to be a permanent cure?

False- Considered being palliative; meaning eliminates symptoms, but not a permanent cure. Replacing one disease for another

 Where are homograft prosthetic valves obtained?

Obtained from cadavers and cryopreserved quickly after death.

What valve is replaced with a homograft prosthetic valve and why?

Aortic valve - Mitral valve replacements have proven largely unsuccessful and fail within 5 years due to leaflet thickening calcification, and regurgitation.

How does a homograft prosthetic valve fail?

Failure usually results from a gradual increase in AI.

How does a tissue prosthetic valve fail?

Degeneration is the main risk of failure.

True

What kind of medication will a tissue prosthetic valve person have to take for the rest of their life and why?

Antibiotics before dental work to prevent staph infections

How durable are tissue prosthetic valves before they fail?

Low durability with few surviving 10 years, & 5 years in the mitral position

True/False- Incidence of endocarditis is low with a tissue valve.

False- tissue valves are more likely to become infected with endocarditis. 

Is there a difference between stented and unstented homograft prosthetic valves?  If yes what is it?

Yes.  Unstented valves are slightly more echogenic than native valves and are made by removing the entire aortic root and adjacent aorta as a block, then is sewn into the root.

What is the Ross Procedure? 

Pulmonic valve is used to replace a diseased aortic valve.  Then the pulmonic valve is replaced with a homograft pulmonic valve.

Where does the pulmonic valve come from for the Ross Procedure?

It comes from the same patient needing the Ross Procedure.

In what valve positions are porcine valves used?

Mitral, aortic and tricuspid valve positions

How long will porcine tissue valves last?

10 – 15 yrs

How are porcine valves made?

They are constructive of aortic porcine valves sewn to a metal wire stent, often made from a cobalt-nickel alloy.  The wire is bent to form three U-shaped prongs.  A Dacron cloth sewing skirt is attached to the base of the wire stent, and the stents themselves are also covered with cloth.

True/False- Porcine tissue valves are treated with gluteraldehyde to make them stiffer?

TRUE

What is a disadvantage of porcine tissue valves?

Limited sizes are available & Small valve sizes will sometimes have “incomplete openings” due to small orifice, and with lower flow rates, creates a favorable environment for failure (size mismatch).

What material is used to make bovine tissue valves?

Fashioned from cow pericardium

How will a bovine tissue valve fail?

Valvular regurgitation or stenosis are the common methods of failure.

What is the advantage of bovine tissue valves?

Unlimited range of sizes can be custom designed.

What medication will a patient need to take for the rest of their life with a mechanical valve? Why?

What types of patients are better suited for a mechanical valve? Why?

Younger male patients or females who don’t plan to become pregnant.  Coumadin can cross the placental barrier and it is dangerous for the baby.

Which prosthetic valves are the most durable out of all of the prosthetic valve types?

Mechanical valves

True/False- It is normal for mechanical valves to have a small amount of regurgitation?

TRUE

What is pannus?

An overgrowth of tissue around the valve perimeter

What is a perivalvular leak?

A leak around the valve annulus

What is the usual cause of a perivalvular leak?

Suture failure

How will a mechanical valve fail?

Pannus & suture failure

What are the types of mechanical valves?

Ball-In-Cage, Single Disc Tilting Disc, Bi-leaflet Tilting Disc

How are Ball-In-Cage mechanical valves constructed?

Two U-shaped struts form a cage that houses a silastic ball occluder.

What is the mechanism of failure for a Ball-In-Cage mechanical valve?

The ball would swell and freeze in the open or closed position

What type of medication will a patient have to take with a Ball-In-Cage valve?

Anticoagulants

What is the disadvantage of Ball-In-Cage mechanical valves?

The ball was notorious for causing damage to blood cells due to collisions.

Are Ball-In-Cage mechanical valves still being used today?

No, they were eventually taken off the market.

How was the Single Disc Tilting Disc valves supposed to be an improvement over Ball-In-Cage valves?

Single Disc Tilting disc valves were designed to mimic the natural patterns of blood flow.  This reduced damage to blood cells, improved flow patterns, reduced blood clotting and infections.

What is the mechanism of failure for a Single Disc Tilting Disc valve?

The struts tend to fracture due to fatigue from repeated ramming of the struts by the disc.

How are Single Disc Tilting Discs constructed?

A polymer disc held in place by 2 welded struts.  The disc floats between the two struts in such a way, as to close when the blood begins to travel backward and then reopens when blood begins to travel forward again.

How are Bi-Leaflet Tilting Disc valves constructed?

Consisted of 2 semi-circular leaflets that pivot on hinges.  The carbon leaflets were strong and had excellent biocompatibility.

When was the first Bi-Leaflet Tilting Disc introduced?

1979

When performing Doppler on a Bi-Leaflet Tilting Disc where should the cursor be placed to get an accurate velocity? Why?

Move the cursor to the side a little because the unusual profile causes the flow velocities to be higher when obtained from the central, slit like orifice.

True/False- Bi-Leaflet Tilting Disc valves provide the closest approximation to central flow achieved in a natural heart valve.

TRUE- The leaflets swing open completely, parallel to the direction of blood flow. 

True/False- Bi-Leaflet Tilting Disc valves are considered an ideal valve.

FALSE- The leaflets don’t close completely, which allows some backflow. Since this is a property of a defective valve, the bi-leaflet valve is still not an ideal valve.