Changes in Retrobulbar Blood Flow over Time in Patients with Glaucoma

Abstract

Purpose: : To examine associations among changes over two years in retrobulbar blood flow parameters in patients with open angle glaucoma (OAG).

Methods: : 100 OAG patients were examined at baseline and following 2 years follow up for retrobulbar blood flow as measured by color Doppler imaging (CDI) in the ophthalmic (OA), central retinal (CRA) and temporal (TPCA) and nasal (NPCA) short posterior ciliary arteries. In each vessel, peak systolic (PSV) and end diastolic (EDV) blood flow velocities as well as vascular resistance (RI) were examined. Associations between the changes in blood flow parameters were evaluated using Pearson correlation coefficients.

Results: : In this cohort of patients with OAG there was a fairly strong positive correlation between OA PSV and OA EDV (r=0.67), while change in OA PSV was moderately correlated with OA RI change (r=0.43) and not significantly associated with other flow parameters that changed significantly. OA EDV and OA RI changes were negatively associated (r=-0.28 overall, r=-0.72 in African decent OAG patients) while OA EDV and TPCA EDV changes were positively associated (r=0.20). Changes in OA RI were positively associated with changes in TPCA RI (r=0.38) and negatively associated with changes in CRA EDV (r=-0.28), NPCA EDV (r=-0.29), and TPCA EDV (r=-0.31). Change in CRA PSV was positively associated with changes in CRA EDV (r=0.65), NPCA PSV (r=0.21), and NPCA EDV (r=0.28). Change in CRA EDV was positively associated with changes in NPCA EDV (r=0.37) and TPCA EDV (r=0.30) and negatively associated with changes in TPCA RI (r=-0.26). Change in NPCA PSV was positively associated with changes in NPCA EDV (r=0.73), TPCA PSV (r=0.39), and TPCA EDV (r=0.40). Change in NPCA EDV was positively associated with changes in TPCA PSV (r=0.35) and TPCA EDV (r=0.50) but negatively associated with changes in TPCA RI (r=-0.31). Change in TPCA EDV was positively associated with change in TPCA PSV (r=0.75) and negatively associated with TPCA RI (r=-0.56), but TPCA PSV and RI were not correlated (r=0.07).

Conclusions: : The relationship among retrobulbar blood vessels is complex and non-linear. A strong correlation between changes in OA PSV and EDV was found along with various CRA and TPCA and NPCA relationships.

Keywords: blood supply • ischemia • imaging/image analysis: non-clinical