Karthaus EG, Vahl A, van der Werf LR, et al. - As per guidelines, surgical treatment is recommended for asymptomatic abdominal aortic aneurysms (AAAs) with a diameter of at least 55 mm for men and 50 mm for women. Researchers here appraised reasons to deviate from these aneurysm diameter thresholds, and focus on the difference in how Dutch vascular surgical units (VSUs) perceive their deviation and their actual deviation. They assessed 9,039 patients who were undergoing elective AAA repair between 2013 and 2016 registered in the Dutch Surgical Aneurysm Audit (DSAA). Analysis suggest regular deviation of Dutch VSUs from the guidelines regarding aneurysm diameter, with variation between VSUs. A lower percentage of deviation was observed, over time, in 21 VSUs vs the national mean each year and there were 8 VSUs with a higher percentage. Concomitant large iliac diameter (91%) and saccular aneurysm (82%) were the most commonly inscribed reasons to deviate. As per estimates by the majority of the VSUs (77%), their guideline deviation was < 5%. By 11 VSUs (25%), their estimated deviation was concordant with their DSAA percentage, but there were 75% of VSUs that underestimated their deviation.