Aqueous Angiography Guided Bent Ab Interno Needle Goniectomy in High versus Low Aqueous Humor Outflow Regions in POAG: A Pilot RCT.

Abstract

Prcis: Trabecular cutting minimally invasive glaucoma surgery like bent ab interno needle goniectomy (BANG) when performed in baseline aqueous angiography identified low aqueous humor outflow regions, results in greater success of intraocular pressure reduction.

Purpose: To study the efficacy of Bent Ab Interno Needle Goniectomy (BANG) in high versus low aqueous humor outflow (AHO) regions as determined by Aqueous Angiography(AA) in patients with primary open angle glaucoma (POAG).

Methods: A prospective, single-centre, pilot, randomized control trial recruited 30 eyes of 30 patients of POAG and visually significant cataract (45-80 y) and were randomised into two groups ("A": BANG performed in the high-flow regions and "B": BANG performed in the low-flow regions) of 15 each. AA was performed using indocyanine green dye (0.1%) to identify baseline high- and low-flow regions of the AHO pathways followed by BANG in these respective regions as per randomisation. Preoperative and postoperative data on IOP, number of antiglaucoma medications (AGMs) and any complications were noted over 6 months. Overall success was defined as achieving an IOP ≤15 mm Hg and ≥6 mm Hg at 6 months of follow-up with AGMs (qualified success) or without AGMs (complete success).

Results: AA revealed high-flow regions of AHO pathways in the nasal quadrant and low-flow regions of AHO pathways in the temporal quadrant in all 30 patients. Both groups had comparable demographic composition [group A age: 65.3±6.48 y and male: female (14:1) and group B age: 64.6±7.08 y and male: female (13:2)]. The mean preoperative IOPs [group A (17.27±3.43 mm Hg); group B (17.60±5.42 mm Hg)] (P=0.842) and mean postoperative IOP at 6 months [group A (15.6±4.98 mm Hg); group B (13.13±2.29 mm Hg)] (P=0.09) were similar. However, lower qualified success was seen in group A (40.00%) compared to group B (86.67%; P=0.021). Survival in Kaplan-Meier analysis was higher in group B (P=0.021). Complications were comparable in both groups.

Conclusion: Short-term results of BANG in low-flow AHO regions show enhanced success compared to those in high-flow AHO regions. This study suggests that trabecular cutting minimally invasive glaucoma surgeries (like BANG) may be performed in baseline low-flow AHO regions (temporal quadrant) instead of the high-flow AHO (nasal quadrant) regions.