Clinical Relevance and Prognostic Significance of Isolated Angiitis of the Vasa Vasorum in Temporal Artery Biopsies.

BACKGROUND

Temporal arteritis (TA) is the most common vasculitis over age 50. Untreated, many patients will suffer blindness or stroke. Gold standard diagnosis is achieved by temporal artery biopsy. The aim of this study was to investigate the relevance of small vessel inflammation.

METHODS

Our dataset was comprised of 72 temporal artery biopsies subjected to a blinded uniform re-examination paired with clinical data including demographics, history, physical examination and laboratory findings. Documented pathology variables included the presence or absence of TA, angiitis of vasa vasorum (AVV) and inflammation of small peri-adventitial vessels (small vessel vasculitis, SVV).

RESULTS

Clinical and pathological variables were subjected to multivariate analysis. In brief, 25% of cases were identified as TA, 20% as isolated AVV, 7% as isolated SVV and 5% as mixed isolated AVV/SVV, while 43% had no inflammation (NI). All cases of TA were accompanied by small vessel inflammation: 95% exhibited AVV with or without SVV, and 5% exhibited SVV alone, demonstrating a strong association between TA and small vessel inflammation. Of the 24 cases with isolated AVV/SVV, 26% received a clinical diagnosis of TA within one year in comparison to 13% of cases that had NI. Furthermore, isolated AVV/SVV was identified in 25% of patients with a high clinical probability for TA, 60% of whom acquired a diagnosis of TA on clinical grounds within one year of follow-up.

CONCLUSIONS

Our findings suggest that isolated AVV/SVV identifies a subgroup of patients with a higher risk of harboring or developing TA.