AimsTo assess intima-media thickness (IMT) changes measured by ultrasound in axillary arteries of giant cell arteritis (GCA) patients over time and to calculate an ultrasound cut-off value for the diagnosis of chronic axillary artery involvement in patients with longstanding GCA.
MethodsUltrasound of both axillary arteries was performed in 109 GCA patients at time of diagnosis and at several follow-up visits and in 40 healthy controls (HCs). IMT determined at the prospective follow-up visit was compared between GCA patients with (axGCA) and without (non-axGCA) vasculitis of axillary arteries at baseline, as well as with HCs. Changes in IMT were depicted. Receiver operating characteristics were performed for cut-off calculations. Inter-/intra-rater agreement was evaluated using stored images and intraclass correlation coefficient (ICC).
ResultsSeventy-three patients were in the axGCA and 36 in the non-axGCA group. Pathological IMT of axillary arteries (axGCA) declined in the first 18 months of treatment by -0.5 mm, (range -2.77 to 0.50), independent of age and gender. Median IMT, after median disease duration of 48 months (16-137), was 0.90 mm (0.46-2.20) in axGCA and 0.60 mm (0.42-1.0) in the non-axGCA group pooled with HCs. An IMT of 0.87 mm was highly specific (specificity 96%, sensitivity 61%) for diagnosis of chronic axGCA. Intra-rater and inter-reader agreement of ultrasound images were good [ICC 0.96-1.0 (three readers) and 0.87, respectively].
ConclusionPathological IMT of the axillary artery declined under treatment. An IMT of 0.87 mm is highly specific for diagnosis of chronic vasculitis of axillary arteries in long-standing GCA patients.