Gebäude 21, 1. OG
Tel.: +49 30 838 62901 (Sekretariat)
After anchor stents and stented grafts have been successfully tested in experiments carriedout by different teams this paper shows results achieved after implanting macroporous stents-graftsin artificially created infrarenal aortic aneurysms at dogs. It turned out that aneurysms could bereliably excluded by open, but very narrow porous stents having pore widths smaller than 0.7 mm²On the other hand, a delayed exclusion forming only a partial thrombus was proven after implantingstents having pore widths of more than 0.85 rnm²The separated thromboses of completely excluded aneurysms showed an acellular, denselycompacted fibrin rnass streaked by septa of connective tissue. In the aneurysms syntheticallycreated of Dacron, a trausinterstitial growth of connective tissue through the aneurysm wall limitedto approximately 5 mm could be proven. In the aneurysms having a mieroporous wall ofpolyurethane there was also an organisation of connective tissue, which was obviously not createdby a transinterstitial sprouting but caused through elements of connective tissue growing forwardfrom the adjacent native aortic walls or through nidation of omnipotent blood cells. The stent-graftswere early characterised by pseudointima having different thicknesses and a confluent surface celllayer on the segments adjacend to the aorta, and a large size graft endothelium infestation -interrupted like an island - on the parts linking the aneurysms.The thickness of these pseudointima decreased with an increasing time of observation . Allcorrectly implanted metal prostheses remained free, if they had been implanted into completelychanneled aortic aneurysms.Despite of correctly placed stent-grafts, a thrombolytic recirculation into the previously excludedaneurysm occured later in one animal. A further reduction of the mesh size - as it is done at the socalled "coknit-stent-graft" (PIQUET et al., 1994) - could reduce thispotential risk of open potash stent grafts.The operative exclusion of human abdominal aortic aneurysms (AAA) by implanting syntheticgrafts is an established therapy for decades in the elective as well as in thesymptomatic stage. However, after having obtained the experimental and initial clinical experience,the transfemoral implantation of endoluminal stent-gmft-systems seems to be a future alternative tothe transperitoneal surgery in selected cases.