Life support systems : the journal of the European Society for Artificial Organs最新文献

Cell coating with human embryonal fibroblasts was examined on solid (Plathurane UM 8300) and microporous (Tecoflex 80 A) polyurethane. Using measurements of cellular growth kinetics and adhesion strength it was found that the onset of cellular growth on the microporous material was delayed but that the vitality and adhesion strength of the cells were better than for the solid material.

1. The new pericardial valves tested showed better hydrodynamic performance than the porcine and the St. Jude Medical mechanical valves. 2. The Ionescu-Shiley III valve exhibited the best hydrodynamic performance, with the least transvalvular energy loss. 3. Transvalvular energy loss shows that the major loss across the 19 mm valves occurs during the forward-flow phase. 4. Our data compares well with data from other in vitro tests performed using different test apparatus. 5. The pericardial bioprostheses, in particular, function well in the 19 mm size and therefore offer an alternative to the increased operative risk associated with valve over-sizing or orifice enlarging procedures. 6. The performance of the two porcine valves tested were comparable with each other.

This extensive morphological study (macroscopy, x-ray, histology, histochemistry and electron microscopy) compares two types of bioprosthetic valves, porcine aortic (PAV) and bovine pericardial (BPV) of various models, both unimplanted (five) and explanted (229). There were 197 PAV and 32 BPV explanted from the mitral, aortic and tricuspid positions, with a mean duration of implantation of 70.3 and 13.5 months, respectively. Within that material, a smaller, rather homogeneous, series of 11 Carpentier-Edwards PAV (CE) and 11 Ionescu-Shiley BPV (IS) explants (mean implantation period 53 and 49, mean patient-age 45 and 47 years) made the comparison of clinical and macroscopic features more valid. In the total series, the leading causes of failure were cuspal tear/perforation with calcification in the PAV group (64 per cent); non-calcified leaflet rupture (27 per cent) and infective endocarditis (27 per cent) in the BPV group. In the small series of CE PAV and IS PAV, the characteristic modes of failure were calcified juxta-commissural cusp rupture for CE and non-calcified leaflet rupture at the suture for IS. The most characteristic x-ray features were calcification of fibrous cords irradiating from the commissures and calcific nodules in the centre in PAV and large plaques extending from the commissures and leaflet base in all directions in BPV. The main microscopic features of leaflet degradation were: the soaked sponge phenomenon (loosening and plasma and fat insudation) and the nodular, protein-rich calcification, both centred in the spongiosa, in PAV explants; important macrophagic activity and destruction of collagenous structures at the outflow layer and along the suture of the leaflets, with preservation of the middle layer, and the intrinsic calcification of the deep collagenous bundles, in BPV explants. Those alterations and other features are discussed with reference to leaflet structure and design, haemodynamics and possible causal mechanisms.

The development of a tracheal prosthesis was evaluated using in vivo data on mechanical loads in the natural organ. The application of in vivo loads to the explanted organ in a laboratory tester was shown to give information on the natural reaction forces of the organ. It is therefore possible to perform in vitro tests on various prosthesis prototypes under near-natural stress conditions and to adapt the prostheses accordingly before implantation.