Thoracic aorta involvement in giant cell arteritis: a case-control analysis of morphological data at diagnosis.

Objective. Giant cell arteritis (GCA) is a cause of potentially fatal aortic aneurysms. Descriptive data on thoracic aorta measurements at the beginning of the disease are lacking. We aimed to compare aortic diameters between a recently diagnosed GCA population and an age- and sex-matched control group. Methods. Patients with GCA and with an available thoracic CT concomitant with diagnosis were included. Controls were patients matched for age and sex and hospitalised in the same care centre for pneumonia. The main criteria were the anteroposterior and lateral diameters of the ascending thoracic aorta, which were measured by a blinded evaluator. Results. 90 cases and 90 controls were included. Each group comprised 30 males and 60 females for a mean age of 75.1 +/- 9 and 75.7 +/- 10.1 years old. At the time of GCA diagnosis no difference was found between the two groups (anteroposterior diameter 37.1 +/- 5 mm for cases vs. 36.7 +/- 5 mm for controls, p=0.6; lateral diameter 36.6 +/- 5 mm for cases vs. 35.9 +/- 4 mm for controls, p=0.3). Thoracic aorta diameter was not significantly higher in patients with aortitis at diagnosis (n=44) than in cases without aortitis (n=46). Conclusion. Morphologic comparison of thoracic aorta at diagnosis of GCA with an age- and sex-matched control population showed no significant difference. Morphologic evaluation of aorta cannot predict accurately the occurrence of aortic aneurysm. Systematic follow-up according to current recommendations is thus justified.