High glutaraldehyde concentrations mitigate bioprosthetic root calcification in the sheep model.
BACKGROUND
Fixation at high glutaraldehyde (GA) concentrations mitigated bioprosthetic calcification in the rat model. The present study intended to verify this observation in the circulatory sheep model.


METHODS
Porcine aortic roots were either fixed in 0.2%, 1.0%, or 3.0% GA. Eight roots per group were implanted in the distal aortic arch of sheep. After six weeks and six months calcification and inflammation were quantitatively and qualitatively assessed.


RESULTS
By increasing the GA concentration from 0.2% to 3.0%, aortic wall calcification could be reduced by 38% after 6 weeks and 34% after 6 months of implantation (p < 0.01). Mineralization coincided with the presence of elastin although calcium was predominantly found in cell nuclei and membranes. Leaflet calcification was absent in all groups after 6 weeks but in a few leaflets presented as heterogeneous, nodular spongiosa deposits after 6 months. Overall, differences between 0.2%-, 1.0%-, and 3.0%-fixed tissue were quantitative but not qualitative regarding distribution patterns. There was no significant difference in inflammatory host reaction between all groups.


CONCLUSIONS
We have shown in the circulatory sheep model that the anticalcific effect of better cross-linking seems to outweigh the intrinsic pro-calcific effect of GA accumulation in bioprosthetic aortic wall tissue.
Zilla
P
P
Department of Cardiothoracic Surgery, University of Cape Town Medical School, South Africa. ctszilla@Samiot.uct.ac.za
Weissenstein
C
C
Human
P
P
Dower
T
T
von Oppell
U O
UO
D000818:Animals; D001013:Aorta, Thoracic / Q000473:pathology / Q000601:surgery*; D001705:Bioprosthesis; D019917:Blood Vessel Prosthesis Implantation; D002114:Calcinosis / Q000473:pathology*; D004305:Dose-Response Relationship, Drug; D005404:Fixatives; D005976:Glutaral / Q000494:pharmacology*; D011183:Postoperative Complications / Q000473:pathology*; D012756:Sheep; D013552:Swine
D005404:Fixatives; D005976:Glutaral