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Comparative assessment of calcification of leaflet materials in the rat subcutaneous model allows assessment of processes of tissue treatment of leaflet materials. Calcification is the leading cause of long-term failure of pericardial valves. We report the results of comparison of the Lotus valve leaflet tissue to that of the approved Mitroflow valve.
18 animals were implanted for 30 (N=5), 60 (8) or 90 (5) days. Each animal was implanted subcutaneously with 6 tissue disks per animal (3 test disks/3 control disks). Following euthanasia, the implant sites were fixed, processed, and stained with hematoxylin and eosin (MEDSTAR&E), Masson’s Trichrome (MT) and von Kossa (VK) for light microscopy. A subset of samples were analyzed for calcium content and reported as ug/mg dry tissue weight. (Table)
Of the 108 total tissue disks implanted, 75 were analyzed for calcium content, (Table), with remainder for histologic analysis. No microscopically detectable calcification was observed in the Lotus disk at 30, 60 or 90 days. The Control disks showed mild to severe calcification at 30, 60 and 90 days.
Implantation of the Lotus and Control articles showed a lack of calcification in the Lotus group at all time points whereas the Controls showed mild to severe calcification at 30, 60 and 90 days. Average calcium content was lower for the Lotus valve. The Lotus valve tissue has less potential to calcify compared to the Control material.
|Average + SD||Max||Min|
|Lotus||9||1.09 ± 0.13||1.30||0.93|
|Mitroflow (control)||11||64.95 ± 30.18||121.00||27.70|
|Lotus||20||1.14 ± 0.12||1.51||0.98|
|Mitroflow (control)||12||109.66 ± 57.51||169.00||2.30|
|Lotus||11||1.46 ± 0.27||2.05||1.14|
|Mitroflow (control)||12||170.25 ± 20.35||204.00||145.00|