Cavitation bubbles - result on echo

[Mb]

Hello everyone!

My husbands' most recent echo reported "cavitation bubbles".

Does anyone have any links/info on this?

Thanks!

Marybeth

 

[Nancy]

Hi Marybeth-

Check out our own member Stevo who is a physicist doing work on heart "appliance" engineering, I think. It seems that all the info is highly technical on the web. Maybe he can explain what it would mean.

 

[John Cochran]

As we all know, nothing is simple when it comes to heart valve surgeries. Cavitation bubbles are a phenomenon in fluid dynamics that are caused by the local acceleration of a fluid, such as blood, over a hinge, leaflet, or other rotational point.

This phenomenon is mainly associated with mechanical valves, and is related to a situation when velocities of the blood increase at a specific location, resulting in an unnatural flow of the blood--kind of a spinning or whirling--that can cause bubbles. If you've ever seen under-water pictures of a boat propellor spinning, with bubbles forming around the water flow, you've seen cavitation.

When these bubbles "pop" or implode, they can cause damage to blood, tissues and even the valve itself.

I imagine that in this case, they want to determine the magnitude of the cavitation, and if serious, they'll want to find out what has changed in the valve's hemodynamics (how the blood flows in the vicinity of the valve) that has resulted in cavitation bubbles being formed.

Best wishes, and hope this helped a little,
--John

 

[Mb]

Nancy and John:

Thanks for the info. I will email Steve (Nancy, you've got an incredible emmory), and John, that was a really good explaination. I wonder if this is caused by the tricuspid leaking (although that's the other side of the heart). His echo also said mild to moderate mitral leakage. I did understand that all mechanicals have some leakage built in flor slippage, but maybe the cavitation is causing the add'l leakage??? Maybe Steve will know.

Thanks again!

Marybeth

 

[Nancy]

Hi John-

Good explanation. I wonder if this is similar or the same as the "turbulence" that has been mentioned around Joe's valves that have caused his hemolytic anemia?

Let me know what Steve says, Marybeth.

On the trail of another clue.

 

[Stevo]

This is not necessarily the same as the cause of haemolytic anaemia- high shear stress fields, whilst not necessarily cavitating, can haemolyse the formed elements of blood.
The main problem with cavitation is, as Joe said, that leaflet erosion can become an issue, along with haemolysis, with large gas emboli trailing in a distant third due to their rarity (thank God!). It all depends on how widespread and how large the cavitation effect is as to whether it is seen as a threat to valve patency. Hard to comment really without seeing the ECG's.

Regards,

Steve

 

[Mb]

Steve:

This is actually fairly interesting. In the research that I did, gas emboli were mentioned a number of times. I read where some HV patients have these when an ultrasound is done of the brain. I wondered if perhaps, this is what causes some of the visual problems/ cloudiness, neurological problems that come and go is ome of the folks here on the site. They are always unexplained for these folks. Steve, is this possible?

Also, how long before these bubbles could cause a problem....one year or twenty????? Just curious!

Marybeth

 

[Stevo]

I would say that if a gas emboli was extant in the system and did make it to the brain, I believe it would be somewhat more severe than a blurring of vision- we're talking ischaemic stroke here (excuse the spelling- I'm English and we insist on spelling everything the Latin way!). I honestly do not have a good answer as to why the vision of people should change post surgically.

As for how long it would take, well that depends on the situation, obviously. As the pulse rate rises, the shear and recirculation downstream of the valve will consequently rise, leading to a greater occurrence of cavitation. The question then is whether this will ever be a large enough cavitation to remain as a gas emboli within the vasculature. My guess would be that this occurs only in VERY extreme cases, and if it did, they'd explant and sort it out before you knew it.

My main question in that case would be how the flow is being conditioned by the damage that may (or may not) be caused to the leaflets due to the cavitation downstream of the device, and whether sites of thrombosis are created by the pitting of the surface.

Let me know what you find out- this is an area of my field, but sadly one that I do not research- give me a nice, steady, stagnating flow anyday!

Regards,
Steve