Carotid artery stenting (CAS) is a minimally invasive endovascular procedure used to treat carotid artery disease and is an alternative treatment option for carotid artery stenosis. Robotic assistance is becoming increasingly widespread in these procedures and can provide potential benefits over manual intervention, including decreasing peri- and post-operative risks associated with CAS. However, the benefits of robotic assistance in CAS procedures have not been quantitatively verified at the level of surgical tool motions. In this work, we compare manual and robot-assisted navigation in CAS procedures using performance metrics that reliably indicate surgical navigation proficiency. After extracting guidewire tip motion profiles from recorded procedure videos, we computed spectral arc length (SPARC), a frequency-domain metric of movement smoothness, average guidewire velocity, and amount of idle tool motion (idle time) for a set of CAS procedures performed on a commercial endovascular surgical simulator. We analyzed the metrics for two procedural steps that influence post-operative outcomes. Our results indicate that during advancement of the sheath to the distal common carotid artery, there are significant differences in SPARC (F(1, 22.3) = 6.12, p =.021) and idle time (F(1, 22.6) = 6.26, p =.02) between manual and robot-assisted navigation, as well as a general trend of lower SPARC, lower average velocity, and higher idle time values associated with robot-assisted navigation for both procedural steps. Our findings indicate that significant differences exist between manual and robot-assisted CAS procedures. These are quantitatively detectable at the granular-level of physical tool motion, improving the ability to evaluate robotic assistance as it grows in clinical use.