[Fwd: WG: [HSF] perimount valve at 3 years]Perimount Histopath

[Rwmfglycar at aol.com]

Dear Roberto.
I see the calcium and some inflammatory cells but no leaflet or collagen  
fibres so I cannot tell whether this calcium is all exophytic. There is no  
evidence of infection. However it is helpful to know whether collagen fibres are  
calcified in trying to analyse the cause of this event. See if the pathologists 
 have any tissue left. Even if it has been in formalin both further histology 
and  calcium measurements can be made. I believe I see a white nodule on each 
of the  other two leaflets and I am presuming that these are also calcium 
deposits. If  there is some calcium in all three leaflets in this mature  person  
then either a tissue factor in three leaflets (perhaps all cut from one piece 
of  pericardium) or a host factor or both are at work. Seeing some 
microscopic  calcium deposits or getting a higher than expected calcium level in the 
other  two leaflets would obviously be useful information. Note that whatever the 
 circumstances physical stress may determine where the calcium is  deposited. 
The area where the major deposit sits is where eddy currents (a  la Leonardo) 
occur during during flow and also where the leaflet has major  stress during 
closure.
One of the difficulties of the valve business is that the ultimate model  
must be the patient. None of us accumulates  more than anecdotal experience  of 
explanted valves, and we seldom share our experience with more than one or  two 
people. Pathologists are rarely fluid dynamics or structural engineers,  
surgeons are rarely pathologists or biochemists and so on. We are just not set  up 
to get to the bottom of these issues. To get answers we need intensive study  
by a dedicated task force of all removed valves. I once was dumb enough to  
suggest that all the companies that make valves should pool all their  
information on all their returned valves. I did not get more than two steps to  first 
base on that one (or if baseball is not your summer sport, my feet   and bat 
had barely left the crease before I was stumped). Roberto has done the  right 
thing in showing this valve. Everybody needs to do it.
Bob