OCT and OCT-A Findings in Giant Cell Arteritis: PAMM as a Specific Ischemic Marker

Summary

GCA: PAMM is highly specific, especially in the presence of AION (but low sensitivity) in biopsy-positive patients — prospective, 70 patients.

Abstract

Purpose: To assess the diagnostic value of tomographic signs on OCT and OCT-A, particularly paracentral acute middle maculopathy (PAMM), in predicting temporal artery biopsy (TAB) positivity in suspected giant cell arteritis (GCA), irrespective of ophthalmologic involvement.

Methods: This prospective monocentric study included patients referred for TAB between January and October 2023. All underwent bilateral macular and optic nerve OCT and OCT-A using AngioPlex CIRRUS HD-OCT (Carl Zeiss Meditec). TAB-positive patients were considered biopsy-proven GCA. Primary analysis focused on the association between PAMM and TAB positivity. Secondary analysis explored vascular choroidal index (CVI), radial peripapillary capillaries (RPC), and OCT-A abnormalities.

Results: Among 70 patients, 22 (31%) had positive TAB. PAMM was observed exclusively in TAB+ patients (n = 8), with specificity and positive predictive value of 100%. Sensitivity and negative predictive value were 38.1% and 77.6%, respectively. Homolateral anterior ischemic optic neuropathy (AION) was always associated with GCA. CVI and other OCT-A findings did not differ significantly between groups. RPC density was significantly reduced in eyes with ophthalmologic involvement ( P = 0.017).

Conclusion: PAMM is a highly specific OCT sign of TAB positivity in suspected GCA. This noninvasive marker may support early therapeutic decisions in suspected GCA.