Comparison of Aortic Diameter and Area After Endovascular Treatment of Aortic Dissection

Background: Different methods have been used to assess remodeling of the thoracic aorta after endovascular treatment of Stanford type B aortic dissections. Changes in morphology may be described using diameter, area, or volume. The aim of this study was to determine if aortic diameter measurements could be used to approximate aortic area in order to refine reporting standards.

Methods: The study population encompassed 100 patients enrolled in the VIRTUE registry (designed to assess thoracic endografting with the Valiant Stent Graft System [Medtronic, Minneapolis, MN] for the treatment of type B aortic dissections). Diameter and area measurements of the true lumen, false lumen, and whole aorta were made using three-dimensional computed tomographic (3D CT) workstations, at different anatomic locations. Measurements included preoperative, postoperative, and follow-up scans. The Pearson test was used to determine general correlation between diameter and volume at each location. Scatter plots were drawn and linear regression models were used to draw a line of best fit. Comparison of these with nonlinear models was performed.

Results: Aortic true and false lumen diameter and area showed good correlation (p < 0.001) in the majority of anatomic locations. This relationship was present preoperatively and during follow-up (p < 0.001). The linear regression models fit well with high R(2) values. At very large aortic sizes nonlinear models were a slightly better fit, but this was not significant.

Conclusions: Aortic diameter measurements correlate with luminal areas in patients with type B aortic dissection. This implies area increases proportionately with diameter over time. Therefore, diameter measurements using multiplanar reconstructions based on a central luminal line appear to be adequate when assessing aortic remodeling after endovascular treatment of aortic dissection.