Aortic involvement in giant cell arteritis: current data.

Aortitis due to giant cell arteritis (GCA) is rare but probably underestimated given the frequent paucity of symptoms. Thus, early studies relied on the occurrence of complications to estimate the prevalence of GCA aortitis. With this method, aortitis was a feature in 3 to 18% of GCA patients. Since then, the introduction of modern imaging techniques has established that aortitis is more common than previously thought. Aortitis should be considered in patients with atypical clinical presentations of GCA consisting, for instance, in isolated laboratory evidence of systemic inflammation or a relapse during treatment. Aortitis may be difficult to diagnose, as temporal artery biopsy has limited sensitivity in patients with predominant large-vessel involvement. Positron emission tomography (PET) and magnetic resonance imaging (MRI) are both highly effective for the early diagnosis of aortitis. Case-series evaluating PET in patients with GCA found evidence of aortitis in over half the cases, with predominant involvement of the thoracic aorta. To date, no evidence is available about the potential usefulness of PET or MRI in monitoring patients with GCA aortitis over time. Involvement of the aorta and other large arteries does not change the treatment strategy, which rests on corticosteroid therapy. Administration of a corticosteroid-sparing drug should be considered, most notably when a relapse occurs. Aortitis is associated with an increased risk of aneurysm of the thoracic aorta. Consequently, all GCA patients should be monitored for aneurysm at regular intervals, even after treatment discontinuation. The recommended strategy is an annual evaluation including a chest radiograph, echocardiogram, and abdominal Doppler sonogram; these imaging studies can be replaced by contrast-enhanced computed tomography of the chest and abdomen.