An ultrastructural study of the intimal injury induced by an indwelling umbilical artery catheter.

In an experimental study, catheterization of the abdominal aorta with small umbilical artery catheters consistently produced significant intimal injury. The duration of catheterization varied from 1 hr to 7 days, and recovery periods following catheter removal varied from 1-150 days. Endothelial disruption was observed in all animals sacrificed within 24 hr of catheter removal. Healing progressed rapidly when the duration of catheterization was short, but was protracted with longer periods of catheterization. Thrombi were frequently found adhering to the exposed subendothelial surface. Routine light, scanning, and transmission electron microscopy demonstrated consistent cellular changes, which depended upon the duration of catheterization and the length of recovery periods. A consistent relationship between the degree of intimal injury and the duration of catheterization was observed.