Clinical and pathological evolution of giant cell arteritis: a prospective study of follow-up temporal artery biopsies in 40 treated patients

Abstract

Although clinical signs and symptoms of giant cell arteritis improve promptly after starting glucocorticoid therapy, reports have suggested that the vascular inflammation may persist. To assess the duration and quality of histopathologic changes in treated patients, we prospectively obtained second temporal artery biopsies in patients treated for 3 to 12 months after their first diagnostic biopsy. Forty patients (28 women, 12 men, median age 77 years) agreed to have a second temporal artery biopsy randomly assigned to 3, 6, 9, or 12 months subsequent to the first. Clinical and laboratory evaluation of the patient cohort revealed a typical rapid response and continued suppression of clinical manifestations as a result of glucocorticoid treatment. Histopathologic findings, evaluated in a blinded manner by a cardiovascular pathologist, showed unequivocal findings of vasculitis in 7/10 patients with second temporal artery biopsy at 3 months, 9/12 at 6 months, 4/9 at 9 months, and 4/9 at 12 months. Lymphocytes were present in all positive initial biopsies and remained the dominant cell population in chronically treated patients. Granulomatous inflammation decreased in a time-dependent manner from 78 to 100% at initial biopsy to 50% at 9 months and 25% at 12 months. The increased medial fibrosis noted in the second biopsies (60 vs 33% in primary temporal artery biopsies) suggested that the finding may represent a chronic finding in arteritis. In summary, the response to glucocorticoids in giant cell arteritis was frequently discordant. Clinical manifestations were readily suppressed, but vascular changes were gradual and often incomplete.

Figure 1

Example Photomicrographs exhibiting (A) a temporal artery with active granulomatous arteritis at the time of initial biopsy, and (B) ongoing active granulomatous arteritis at 6 months, post biopsy (hematoxylin and eosin staining; original magnifications, x200). Early calcification is also apparent in the follow-up sample (arrowhead).

Figure 2

The incidence of granulomatous inflammation in second temporal artery biopsies by cohort. Overall, the incidence of granulomatous inflammation detected in a biopsy is indirectly related to the length of glucocorticoid therapy.

Figure 3

Example photomicrograph showing extensive chronic remodeling, characterized by medial disruption (arrows), extensive medial fibrosis (asterisk) and loss of the internal elastic membrane (Verhoeff-van Giesson staining; original magnification, x40).

Figure 4

Example photomicrographs showing (A) mild intimal fibroplasia (<25% luminal narrowing, between arrows) and (B) marked intimal fibroplasia (>75% luminal narrowing, between arrows) (Verhoeff-van Giesson staining; original magnifications, x40).