Comparison of dynamic changes in aortic diameter during the cardiac cycle measured by computed tomography angiography and transthoracic echocardiography

Abstract

ObjectiveThis study aimed to examine the relationship between dynamic changes in aortic diameter and corresponding measurement methods. MethodsConsecutive adult (nonaneurysmal) patients being surgically treated for heart disease (mean age, 51 ± 11 years; range, 29-76 years; N = 25) were included in this study. All patients underwent transthoracic echocardiography (TTE), computed tomography angiography (CTA), and intraoperative ultrasound (IOUS). Anteroposterior diameters were measured at 1 cm above the junction of the aortic sinus, the proximal 1 cm of the innominate artery, and the midpoint of the two. ResultsThe average diameter of the proximal ascending aorta in systole/diastole measured by IOUS was 32.07 ± 2.03/30.27 ± 2.05 mm (paired t-test: difference, 1.80 ± 0.46 mm; P < .001). The average diameters of the proximal ascending aorta measured by nonelectrocardiography-gated CTA and TTE were 31.45 ± 1.97 mm and 29.7 ± 1.84 mm, respectively. The average diameter of the mid and distal ascending aorta in systole/diastole measured by IOUS was 32.35 ± 1.95/30.57 ± 1.94 mm (paired t-test: difference, 1.78 ± 0.44 mm; P < .001) and 32.32 ± 1.92/30.67 ± 1.90 mm (paired t-test: difference, 1.65 ± 0.42 mm; P < .001), respectively. The average diameter of the mid and distal ascending aorta measured by CTA was 31.74 ± 1.92 mm and 31.59 ± 1.96 mm, respectively. At each location, the difference in the aortic diameter between systole and diastole was statistically significant (all P values <.001; paired t-test). The minimum and maximum changes in the diameter between systole and diastole were 0.90 mm and 2.70 mm. In all, 96% (24/25) of the average diameters derived from IOUS and CTA at the three locations were within the concordance limit in systole, and 92% to 100% (23/25 to 25/25) were within the concordance limit in diastole. The average diameters derived from IOUS and TTE images of the proximal ascending aorta were within the bounds of the concordance limit 92% (23/25) of the time in systole and 100% (25/25) of the time in diastole. The average diameters derived from CTA and TTE images of the proximal ascending aorta were within the bounds of the concordance limit 88% (22/25) of the time. Pearson correlation coefficients between these groups ranged from 0.905 to 0.982 (all P values <.01). ConclusionsThe ascending aorta diameters measured by nonelectrocardiography-gated CTA and TTE were consistent with the IOUS measurements.