Large-Vessel Dilatation in Giant Cell Arteritis: A Different Subset of Disease?

Objective: To compare patients with large-vessel giant cell arteritis (LV-GCA) characterized by wall thickening, stenosis, and/or occlusion of subclavian arteries to those with subclavian dilatation. Methods: For the purposes of the present retrospective study, 2 different subsets of LV-GCA were identified and compared from an established cohort of patients with radiographic evidence of subclavian artery vasculitis secondary to GCA: LV-GCA with wall thickening, stenosis, and/or occlusion of subclavian arteries (Group 1), and LV-GCA with dilatation of subclavian arteries without wall thickening or stenotic changes (Group 2). Results: The study included 109 patients in Group 1 and 11 in Group 2. Large-vessel involvement secondary to GCA was diagnosed significantly later in patients from Group 2 compared to those from Group 1 (median 15.3 versus 0.0 months; P = 0.010). Compared to patients from Group 1, those from Group 2 were more frequently male (17% versus 45%; P = 0.027), ever smokers (42% versus 73%; P = 0.048), and more frequently had a history of coronary artery disease (11% versus 36%; P = 0.018). At LV-GCA diagnosis, 10 of the 11 patients (91%) from Group 2 had aortic dilatation compared to 13 of 109 patients (12%) from Group 1 (P < 0.001). During the followup period, the prevalence of aortic aneurysm was significantly higher in patients from Group 2 compared with those from Group 1 (64% versus 7% at 5 years; P < 0.001). Conclusion: Two different subsets of LV-GCA were identified. Given the strong association between subclavian artery dilatation and aortic aneurysm, such patients should be evaluated and monitored carefully for aortic dilatation.