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Published on: December 7, 2016
Netarsudil 0.02% Alters Episcleral Venous Flowrates: A Clinical Trial Using Erythrocyte-Mediated Angiography
Sarah Kim1, Victoria Chen1, Jessica Pottenburgh2
1Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, Maryland.
Objective:
To characterize the effect of netarsudil 0.02% on episcleral blood flow in treatment-naive glaucoma suspect or ocular hypertension subjects.
Design:
Prospective, unmasked, single-arm cohort study.
Participants:
Ten treatment-naive patients with a diagnosis of glaucoma suspect or ocular hypertension.
Methods:
Erythrocyte-mediated angiography (EMA) was used to measure episcleral erythrocyte velocity, vessel diameter, and blood flow at baseline before treatment, 1 hour after drop instillation (T1), 1 to 2 weeks after daily netarsudil 0.02% drop use (T2), and 1 hour after drop instillation at the 1-to-2-week time point (T3). Intraocular pressure (IOP) and blood pressure were measured at each visit.
Main Outcome Measures:
Change in episcleral venous erythrocyte velocity, diameter, and blood flow between time points analyzed using generalized estimating equation models.
Results:
Of the 18 eligible study eyes of 10 enrolled treatment-naive subjects, baseline IOP was 16.8 ± 3.6 mmHg (mean ± standard deviation), which significantly decreased to 13.9 ± 4.2 mmHg at T1, 12.6 ± 4.1 mmHg at T2, and 11.8 ± 4.7 mmHg at T3 (P < 0.05 at each time point compared with baseline). Episcleral vessels averaged 61.3 ± 5.3 μm in diameter at baseline which increased significantly at all posttreatment time points (78.0 ± 6.6, 74.0 ± 5.2, 76.9 ± 6.9 μm, respectively; mean ± standard deviation, P < 0.05 for each time point). Episcleral venous flowrates were 0.40 ± 0.22 uL/minute (mean ± standard deviation) at baseline, which increased significantly to 0.69 ± 0.45 uL/min at T1 (P = 0.01), did not significantly differ at T2 (0.38 ± 0.30 uL/minute), and increased significantly to 0.54 ± 0.32 uL/minute at T3 (P < 0.05 compared with baseline and T2).
Conclusions:
Netarsudil causes episcleral venous dilation at all time points and resulting increases in episcleral venous flowrates 1 hour after drop instillation. Increased episcleral venous flow, associated with decreased episcleral venous pressure, may result in lowered IOP.
Financial Disclosures:
Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.
