Background: Operative technique used in repair of distal aortic arch diseases is selected mostly on the basis of preoperative diagnosis. Computed tomography (CT) is an effective method in diagnosis because of its easy availability with high specificity and sensitivity rates. Present study aimed to evaluate the diagnostic reliability and predictive value of CT in determination of operation technique by retrospective comparative analysis of operative findings with results of conventional CT in patients with distal aortic disease.

Methods: Thirty-three patients (mean age 51.8 ± 13 years, male 28 and female 5) underwent distal aortic arch operationsbetween 1994 and 2001. Distal aortic diseases diagnosed in CT were grouped as acute type III dissection, chronic type III dissection, and aneurysms. Besides pathological classification, the involvement of left subclavian artery and whether the rupture was present or not were also investigated and compared with the operative findings.

Results: Acute type III dissection reported in CT analyses of 5 patients was also confirmed in operations with positive-predictive value and sensitivity of 100%. Chronic type III dissection diagnosed in 9 patients with CT was detected surgically in 11 patients with positive-predictive value of 81.81% and sensitivity of 90%. Aneurysm diagnosed in 19 patients, was confirmed surgically in 16 patients with pozitive-predictive value of 94.12% and sensitivity of 88.89%. The rupture diagnosed in 3 patients was also confirmed surgically in all patients. Computerized tomography findings were not predictive in determination of operation technique. Besides 2 patients detected in CT, cross-clamping had to be performed proximal to subclavian artery in additional 5 patients. Sensitivity and accuracy of CT in detecting the left subclavian artery involvement were 28.5% and 22.2%, respectively.

Conclusion: The conventional CT is a very effective technique in diagnosis of distal aortic arch diseases and in the detection of rupture, whereas it is not sensitive to show subclavian artery involvement. Therefore, the operative strategy should not be based on the CT findings.

Keywords : Distal aortic arch, computed tomography, aortic surgery