Reduction of the susceptibility to infective endocarditis with time in animals with endocavitary catheters.

In a previous study we showed that the lesions of non-bacterial thrombotic endocarditis induced by means of implantation of a catheter in the left ventricle (LV) of the rabbit, undergo inner connectivization and surface endothelialization, which are completed within 2-3 months. In the present study we have investigated whether these histological changes lead to a variation in susceptibility to infective endocarditis (IE). After studying two control groups, we compared the incidence of IE in four groups of 15 rabbits each, inoculated with Streptococcus mitis I, 10, 35 and 70 days after implantation of a catheter in the LV. The frequency of infection was shown to be progressively reduced from 100% to 26.7%. This demonstrates that endothelialization of the catheter and the sterile vegetations protect the animals from IE.