[Role of the process of endothelium formation on the wall of the aortic prosthesis in protection against infection. Experimental study in dogs].

An experimental canine model was developed in order to evaluate the role of endothelialization of aortic prostheses for protection against septicemic infection and the utilization of 131I radiolabeled bacteria for vascular experimentation. Two groups of dogs were submitted to insertion of a dacron prosthesis segment in the abdominal aorta with subsequent infusion of inert 131I radiolabeled bacteria. In the first group ("A"), formed by five dogs, the infusion was made 30 minutes after the insertion of the prosthesis and in the second group ("B"), formed by four dogs, in a new surgery performed 12 weeks after. Fragments of the animals' prostheses and aortas were collected after 30 minutes of septicemia and analyzed by scan electron microscopy and submitted to reading of radioactivity uptake by a well-type counter. The microscopy recognized a complete endothelialization of the prostheses of dogs of group "B" 12 weeks after their insertion. Statistical analysis comparing fragments of non-endothelialized prostheses, of endothelialized prostheses and aortas demonstrated that the lower radioactivity uptake of the endothelialized prostheses in relation to non-endothelialized ones was significant (p = 0.0143) and that there was no significant statistical difference in uptake in the aortas and in endothelialized prosthesis (p = 0.3173). It was, therefore, concluded that prosthesis endothelialization fully protected them against septicemic infection; bacteremia contaminated all the non-endothelialized prostheses; there was no bacterial adhesion in the endothelialized prostheses and the use of bacteria labeled with radioisotope 131I is appropriate for the study of infections in vascular prosthetic devices.