A prospective study of growth and rupture risk of small-to-moderate size ascending aortic aneurysms.

OBJECTIVE

The natural history of small-to-moderate size ascending aortic aneurysms is poorly understood. To follow these patients better, we have developed a method to objectively and reproducibly measure ascending aortic volume on the basis of gated contrast computed tomography scans.

METHODS

From 2009 to 2011, 507 patients were referred for management of ascending aortic aneurysms. A total of 232 patients (46%) with small-to-moderate size aneurysms who did not have compelling indications for operation had measurement(s) of ascending aortic and total aortic volume; 166 patients had more than 1 scan, allowing measurement of growth. A total of 66 patients admitted to the emergency department without ascending aortic pathology served as a reference group.

RESULTS

None of the patients experienced rupture, dissection, or death; 3 patients ultimately underwent operation. Ascending aortic volume and volume/total aortic volume differed for the surveillance and reference groups: 132.8 ± 39.4 mL versus 78.0 ± 24.5 mL; 38.3% ± 7.4% versus 29.1% ± 3.9%, respectively (both P < .001). Diameters at the sinotubular junction and mid-ascending aortic were 4.1 ± 0.6 cm and 4.4 ± 0.6 cm, respectively, for the surveillance group and 3.0 ± 0.4 cm and 3.2 ± 0.4 cm, respectively, for controls. The increase in ascending aortic volume was 0.95 ± 4.5 mL/year and 0.73% ± 3.7%/year (P = .007 and .012, respectively). Analysis of risk factors for ascending aortic growth revealed only the use of antithrombotic medication as possibly significant.

CONCLUSIONS

Computed tomography volume measurements provide an objective method for ascertaining aortic size and monitoring expansion. Patients with small-to-moderate ascending aortic aneurysms who are carefully followed and managed appropriately have slow aneurysm growth and a small risk of rupture or dissection. Annual computed tomography screening may not be indicated, and elective resection-absent other surgical indications-is not necessary. The rupture/dissection risk for even larger aneurysms in carefully followed patients may be lower than currently believed.