The cardiac cycle is a major contributor to variability in size measurements of abdominal aortic aneurysms by ultrasound.

Aim: The objective of the study was to evaluate the impact of the cardiac cycle on ultrasound measurements of abdominal aortic aneurysm (AAA) diameters.

Methods: In total, 603 AAAs detected by screening were investigated with respect to the maximal systolic and diastolic anterior-posterior aortic diameters during the cardiac cycle using recorded ultrasound video sequences.

Results: On average, the systolic AAA diameter was 41.60 mm, and the diastolic AAA diameter was 39.63 mm with a paired mean difference at 1.94 mm (p < 0.0001). No association between aneurysmal size and difference in systolic and diastolic size was noted. The mean difference and variability between two observers, one measured during peak-systole and the other measured during end-diastole, was 2.65 and 2.21 mm, respectively, as compared with 0.86 and 1.52 mm, respectively, when both were measured during the peak of systole. The intraobserver variability was 0.94 during systole, 1.18 during diastole and 1.94 mm when systole and diastole measurements were combined.

Conclusion: The lack of a standardised measurement of the AAA diameter during the cardiac cycle is a potential major contributor to the variability in ultrasonography measurements.