Enter Note Done
Decrease font size Increase font size

Relationship Between Geographic Atrophy Expansion Rate and Density of Choriocapillaris Flow Voids Using OCT Angiography

View Session View Presentation
Add to Schedule Print Abstract

Posterboard#: A0312

Abstract Number: 3469 - A0312

AuthorBlock: Yining Dai1, khashayar nattagh2, Hao Zhou1, Nicholas Rinella2, Qinqin Zhang1, Katharina G. Foote3, Cathrine Keiner2, Michael Deiner2, Jacque L. Duncan2, Ruikang K. Wang1,4, Daniel Schwartz2
1Department of Bioengineering, University of Washington, Seattle, Washington, United States; 2University of California San Francisco, San Francisco, California, United States; 3University of California, Berkeley, Berkeley, California, United States; 4Department of Ophthalmology, University of Washington, Washington, United States;

DisclosureBlock: Yining Dai, None; khashayar nattagh, None; Hao Zhou, None; Nicholas Rinella, None; Qinqin Zhang, None; Katharina G. Foote, Carl Zeiss Meditec, Inc. Code C (Consultant), Cathrine Keiner, None; Michael Deiner, None; Jacque L. Duncan, California Institute for Regenerative Medicine Code C (Consultant), Foundation Fighting Blindness Code C (Consultant), Editas Medicine Code C (Consultant), Ionis Pharmaceuticals Code C (Consultant), Novelion Therapeutics Code C (Consultant), ProQR Therapeutics Code C (Consultant), SparingVision Code C (Consultant), Spark Therapeutics Code C (Consultant), Foundation Fighting Blindness Code S (Non-remunerative), Neurotech USA, Inc. Code S (Non-remunerative), AGTC Code C (Consultant), Ruikang K. Wang, Carl Zeiss Meditec, Inc. Code C (Consultant), Insight Photonic Solutions, Inc. Code C (Consultant), Daniel Schwartz, None;

Purpose
Expansion kinetics of geographic atrophy (GA) can be highly variable between patients, and currently, no predictive model exists. This study evaluates the relationship between the expansion rate of GA, and choriocapillaris flow void (FV) density near the GA margin.

Methods
This prospective study enrolled subjects with GA secondary to non-exudative AMD at the University of California, San Francisco (UCSF) from July 2016 - November 2018. OCT angiography was used to view en face images of the choriocapillaris. Choriocapillaris FV's (Figure 1A) were evaluated using a validated, one-standard deviation thresholding algorithm. Fundus autofluorescence imaging was used to identify margins of GA, and baseline area was subtracted from follow up area to define regions of GA growth (Figure 1B). GA growth rate was measured as the difference in the square root of GA area, divided by the months elapsed between baseline, and follow-up imaging. GA expansion rate was then correlated to the density of FV (%) within a 2-degree band outside the baseline GA margin.

Results
Eight subjects (14 eyes) with GA secondary to non-exudative AMD were imaged once at baseline, and again 7-14 months after baseline. GA expansion rate was positively correlated with increased choriocapillaris FV density at the GA margin (Pearson's correlation coefficient R2= 0.6835, P < 0.01, Figure 2). Mean GA expansion rate was 20.44 µm/month (STD = ± 20.44 µm/month) and mean FV density within a 2-degree band was 18.77% (STD = ± 7.82%).

Conclusions
There was a significant positive correlation between GA expansion rate and choriocapillaris FV density near the GA margin. These results suggest that quantifying regions of choriocapillaris FV may lead to a predictive model for GA growth.

Layman Abstract (optional): Provide a 50-200 word description of your work that non-scientists can understand. Describe the big picture and the implications of your findings, not the study itself and the associated details.
Geographic atrophy (GA) is an advanced form of age-related macular degeneration that can result in the progressive and irreversible loss of the outer retina (photoreceptors, retinal pigment epithelium, and underlying choriocappillaris), which can lead to a loss of visual function over time. Expansion kinetics of GA can be highly variable among individual patients, and currently, no predictive model exists. The advent of optical coherence tomography angiography (OCTA), and particularly of swept-source technology, has allowed for depth-resolved imaging of retinal vasculature and the underlying choriocapillaris. Using swept-source OCTA technology, this study evaluates the relationship between the expansion rate of GA, and choriocapillaris flow void (FV) density near the GA margin. We found a significant positive correlation between GA expansion rate and choriocapillaris FV density near the GA margin. These results suggest that quantifying regions of choriocapillaris FV may lead to a predictive model for GA growth.