[Aortitis in giant cell arteritis and its complications]

Aortitis is a serious complication of giant cell arteritis (GCA), because of the risk of aortic aneurism, rupture, or dissection. Aortitis is present either at presentation or, more frequently, occurs as a delayed complication, typically as an aortic aneurism of the ascending part of the aorta. An aortic aneurism may occur in up to 10% of patients. Aortitis is sometimes associated to arteritis of the supra-aortic vessels. Risk factors for aortitis remain unknown. Recent clinical studies indicate that prevalence of aortitis was initially under-estimated. Imaging studies show signs of infra-clinical aortitis in 20 to 65% of cases at diagnosis. Using ultrasonography, thickening of the vascular wall with an hypoechoic halo around the abdominal aorta is suggestive of abdominal aortitis. Positron emission tomography shows a metabolic hypersignal of the aorta in about 50% of patients with giant cell arteritis. Aortic computed tomographic (CT) scan visualizes aneurysmal dilatations, ectasia or focal or concentric parietal thickenings. When present at the time of diagnosis of GCA, these findings seem to be associated with frequent relapses and perhaps with a higher long-term vascular mortality rate. Therefore, we recommend the screening of aortitis lesions at GCA diagnosis by an aortic CT-scan and follow-up. Therapeutic trials should be conducted to try to improve the treatment of aortitis in GCA.