Evidence of Deep Capillary Nonperfusion May Predict Diabetic Retinopathy Complications

Amani A Fawzi, MD

(Credit: Northwestern University)

Evidence of deep capillary nonperfusion on optical coherence tomography (OCT) angiography at baseline may predict short-term complications of diabetic retinopathy (DR) with high accuracy in eyes with referrable nonproliferative diabetic retinopathy (NPDR), according to a new investigation.¹

Investigators, led by Amani A Fawzi, MD, Cyrus Tang and Lee Jampol Professor of Ophthalmology, Feinberg School of Medicine, Northwestern University, suggest that deep retinal ischemia may thus play an important pathophysiologic role in DR progression.

“Our results suggest that OCT angiography may provide additional prognostic benefit to clinical DR staging in eyes with high risk,” Fawzi and colleagues wrote.

The prospectively, longitudinal, observational study included a total of 59 patients (74 eyes) with treatment-naive moderate and severe, or referable, NPDR. Included patients were imaged with OCTA at baseline and then followed-up with for 1 year.

Investigators then evaluated 2 OCT angiography capillary nonperfusion metrics, vessel density, and geometric perfusion deficits, in the superficial capillary plexus, middle capillary plexus, and deep capillary plexus. The team compared the predictive accuracy of baseline OCT angiography metrics for clinically significant DR outcomes at the 1-year mark.

The main outcomes were defined as significant clinical outcomes at 1 year, defined as 1 or more of vitreous hemorrhage, center-involving diabetic macular edema, and initiation of treatment with pan-retinal photocoagulation or anti-vascular endothelial growth factor (VEGF) injections.

A total of 49 patients (61 eyes) returned for the 1-year follow-up. Upon analysis, data showed geometric perfusion deficits and vessel density in the middle capillary plexus and deep capillary plexus correlated with clinically significant outcomes at 1-year (P <.001).

The findings reported eyes with these outcomes had lower vessel density and geometric perfusion deficits, suggesting worse nonperfusion of the deeper retinal layers than those that remained free from complication. Results also indicate these differences remained significant (P = .046 to <.001) when OCT angiography parameters were incorporated into models that also considered sex, baseline-corrected visual acuity, and baseline DR severity.

Data showed the adjusted receiver operating characteristic curve for deep capillary plexus geometric perfusion deficits achieved an area under the curve (AUC) of 0.929, with sensitivity of 89% and specificity of 98%.

Investigators noted the findings remained similar in a separate analysis in the study.

“In a separate analysis focusing on high-risk proliferative diabetic retinopathy outcomes, middle capillary plexus and deep capillary plexus geometric perfusion deficits and vessel density remained significantly predictive with comparable AUC and sensitivities to the pooled analysis,” they wrote.

References

1. Ong JX, Konopek N, Fukuyama H, Fawzi AA. Deep capillary nonperfusion on OCT angiography predicts complications in eyes with referable nonproliferative diabetic retinopathy. Ophthalmology Retina. 2023;7(1):14-23. doi:10.1016/j.oret.2022.06.018