Migration of the endoprosthesis is defined as the misplacement of its initial fixation. To assess the migration, the position of the endoprosthesis regarding a certain anatomic region is verified. Considering the aneurysm of the infrarenal abdominal aorta, the proximal area of reference is the origin of the lowest renal artery and, at the distal region, it is located next to the internal iliac arteries. Patients should be monitored for long periods so that migrations can be identified; these migrations usually occur 2 years after the implantation. To avoid migrations, mechanical forces that enable fixation and that are determined by the characteristics of the devices and by the incorporation of the endoprosthesis should predominate over gravitational and hemodynamic forces, which tend to drag the prosthesis toward to caudal direction. Angulation, extension, and diameter of the neck, and transversal measure of the aneurysmatic sac are important morphological aspects related to migration. In relation to the technique, endoprosthesis implantation with excessive oversizing (> 30%) is not recommended because it leads to aortic neck dilatation, folds and proximal leakage that also contribute to migration. On the other hand, endoprosthesis with additional fixation devices (hooks, barbs and suprarenal fixation) seem to be less associated with migration. The process of endoprosthesis incorporation is partial and does not seem to be enough to prevent later migrations. In this sense, experimental studies with endoprosthesis of higher porosity, as well as the use of substances that allow higher fibroplasia and adherence of the prosthesis to the artery, have been conducted and are promising. Such aspects are discussed in the present review of the literature.
Vascular prosthesis; migration; complications; aortic aneurysm
