Pathology of the Pericarbon bovine pericardial xenograft implanted in humans.
OBJECTIVE
Pericarbon is a new-generation bovine pericardial bioprosthesis designed to withstand mechanical wear. Following optimal in vitro testing and animal experiments, clinical trials were initiated in many European centers and explants sent to our department for pathological evaluation. This included gross, radiographic, histologic and ultrastructural investigations.


METHODS
Between 1986 and 1996, 24 bioprostheses (eight aortic, 11 mitral, two mitro-aortic, one tricuspid) were collected from 22 patients (10 males and 12 females; mean age 57.0 +/- 18.9 years) either at autopsy (nine) or reoperation (15).


RESULTS
Ten bioprostheses explanted < 2 months after surgery were either normal or failed because of surgical problems or non-structural causes. Among the other 14 bioprostheses (mean placement 41.9 +/- 23.6 months; range: 7 to 90 months), structural deterioration occurred in seven and was due to dystrophic calcification with stenosis in five (three aortic, two mitral), mixed lesion in one (mitral), and incompetence in one by calcium-related commissural tear (mitral). At the ultrastructural level, calcification was detected either on cell debris or upon collagen fibers. No bioprosthesis failed because of fibrous tissue overgrowth. Of the remaining seven bioprostheses, vegetative endocarditis occurred in two, thrombosis in one, and aseptic paravalvular leak in one; whereas three showed no signs of dysfunction.


CONCLUSIONS
This pathologic experience with the Pericarbon valve showed calcification to be the main cause of late structural failure, causing mainly cusp stiffness and bioprosthesis stenosis. Tissue rupture or abrupt dysfunction never occurred. Thus, prevention of mineralization remains the main challenge.
Valente
M
M
Institute of Pathological Anatomy, University of Padua Medical School, Italy.
Ius
P
P
Bortolotti
U
U
Talenti
E
E
Bottio
T
T
Thiene
G
G
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D001021:Aortic Valve; D001705:Bioprosthesis / Q000009:adverse effects*; D002114:Calcinosis / Q000209:etiology / Q000473:pathology*; D002417:Cattle; D003094:Collagen / Q000648:ultrastructure; D004696:Endocarditis / Q000209:etiology / Q000473:pathology*; D005069:Evaluation Studies as Topic; D005260:Female; D005500:Follow-Up Studies; D006350:Heart Valve Prosthesis / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008422:Materials Testing / Q000379:methods; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D008943:Mitral Valve; D010496:Pericardium / Q000473:pathology*; D011093:Polyethylene Terephthalates / Q000009:adverse effects; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012086:Reoperation; D013314:Stress, Mechanical; D013499:Surface Properties; D014021:Tissue Preservation / Q000379:methods; D014261:Tricuspid Valve
D011093:Polyethylene Terephthalates; D003094:Collagen