Analyzing the Impact of a New β3 Adrenergic Agonist on Chorioretinal and Peripapillary Vessel Density

Abstract

Purpose: To assess the impact of mirabegron, a novel β3 adrenoceptor agonist employed for the treatment of overactive bladder (OAB), on the optic nerve head and chorioretinal vasculature using optical coherence tomography angiography (OCTA).

Materials and methods: Fifty eyes of 25 patients who used a 50 mg tablet of mirabegron once daily for OAB were included in this prospective study. OCTA was performed at 6 × 6 mm of the macula and 4.5 × 4.5 mm of the optic disc. Retinal nerve fiber layer (RNFL) thickness, macular ganglion cell complex(mGCC) thickness, foveal avascular zone (FAZ), choriocapillaris (CC) flow area, CC vessel flow density (VFD), optic nerve head, and macula vessel densities were evaluated before the treatment and 2 months after treatment initiation.

Results: RNFL, mGCC in all quadrants, and FAZ were similar before and 2 months after treatment started point. In optic nerve head vessel density measurements, whole image vessel density (wiVD), mean ppVD (peripapillary vessel density), inferior ppVD, and ppVD in nasal superior, inferior nasal, and temporal superior quadrants measurements following mirabegron treatment were found to be lower than the pretreatment measurements (p < 0.05). Following treatment, wiVD decreased by 1.2% (Cohen's d = 0.26) and mean ppVD decreased by 0.8% (Cohen's d = 0.25), indicating a small effect size. All macular parameters were similar before and 2 months after treatment. No statistically differences were observed in terms of CC parameters.

Conclusion: The reduction in optic nerve head vascularity parameters following mirabegron treatment contributes to understanding the impact of β3-AR agonists, which are being investigated as a therapeutic target for treating retinal vascular diseases. These findings may provide valuable insight into the systemic vascular effects of β3-adrenergic agonists and could be relevant in shaping therapeutic strategies aimed at preserving optic nerve head perfusion, particularly in patients at risk of vascular compromise. Further studies with larger cohorts and longer follow-up are needed to validate these preliminary findings.

Trial registration: This study is a prospective observational study and does not qualify as a clinical trial. Therefore, registration is not required.

Keywords: OCTA; mirabegron; peripapillary vessel density; retinal vascularity.