The Annals of Thoracic Surgery, Vol 54, 952-957, Copyright © 1992 by The Society of Thoracic Surgeons
The Meadox-Gabbay pericardial xenograft: failure of the unicusp principle
U Bortolotti, P Ius, G Thiene, M Minarini, A Milano, C Valfre, E Talenti, M Valente and A Mazzucco
Department of Cardiovascular Surgery, University of Padova Medical School, Italy.
Durability of a new bioprosthesis, the Meadox-Gabbay unileaflet pericardial
xenograft, was evaluated by reviewing a series of 12 patients who received
this device in the mitral position from 1983 to 1985. Bioprosthetic failure
necessitated reoperation in 5 patients 21, 22, 53, 66, and 81 months after
placement. Three patients died of cardiac failure after 31, 52, and 70
months; no postmortem examinations were done. In 2 of the 3 patients, an
echocardiographic study had shown signs of valvular dysfunction.
Pathological examination of five available explants revealed the presence
of redundancy and stretching of the single pericardial leaflet in all of
them; in one, this lesion alone caused severe prosthetic incompetence.
Other pathological findings included cusp and commissural calcification and
commissural tears with or without calcification. Histologic examination and
electron microscopy showed intrinsic calcification involving both collagen
bundles and cellular debris and various degrees of collagen disruption. In
this limited series of patients, the Meadox-Gabbay pericardial xenograft
demonstrated various modes of failure that markedly impair its durability
and render it unsuitable as a cardiac valve substitute.
