Microvascular impairment as a biomarker of diabetic retinopathy progression in the long-term follow up in type 1 diabetes

Abstract

This study aimed to explore differences in vascular and structural parameters using optical coherence tomography angiography in patients with type 1 diabetes (DM1) with mild signs of diabetic retinopathy (DR) over a two-year follow-up period. Parafoveal vessel density (PVD) and foveal avascular zone (FAZ) area were analyzed. The thickness of three predefined retinal slabs was measured, including the inner limiting membrane (ILM)–inner plexiform layer (IPL), IPL–inner nuclear layer (INL), and the IPL–outer nuclear layer (ONL). Twenty-two patients with DM1 and 21 controls were included. There was no significant difference in the FAZ area, perimeter and acircularity index between cohorts over time. Baseline superficial capillary plexus PVD was approximately 10% lower in patients with diabetes than in controls (p = 0.001), and was 12% lower at 2 years (p = 0.002). There was no difference in the annual linear trend between the groups (− 0.5% in diabetics vs. controls, p = 0.736). Baseline deep capillary plexus (DCP) PVD was slightly lower in diabetics than in controls (− 4.4%, p = 0.047) and the difference increased at 2 years (− 12.6%, p < 0.001). The annual linear trend was − 2.7% in diabetic patients compared to controls (p = 0.009). In addition, the PVD of the DCP and the intermediate capillary plexus (ICP) were evaluated separately. Regarding the DCP PVD, no statistically significant difference at any time points in diabetic patients compared to controls and no statistically significant difference in the linear trend was found (p > 0.1). Conversely, no difference was recorded for parafoveal ICP density at individual time points (p > 0.1), but a statistically significant difference in the linear trend over time in diabetic patients compared to controls was recoded (− 3.2% per year, p = 0.001). Despite the apparent intergroup differences at baseline in structural OCT parameters, the differences including ILM–IPL (p = 0.273), IPL–INL (p = 0.708), and IPL–ONL (p = 0.054) were modest and not statistically significant with time. Therefore, the microvascular change of the deeper vessels might be a robust biomarker to evaluate the clinical progression of DR in DM1.

Citicoline in Ophthalmological Neurodegenerative Disease: A Comprehensive Review

“…In addition, the area of the foveal avascular zone (FAZ) showed no significant changes over time in both groups. As already reported, the impairment of DCP represents a biomarker for both early diagnosis and risk of progression in DR [ 124 ].…”

Use of Imaging Technology to Assess the Effect of COVID-19 on Retinal Tissues: A Systematic Review

“…Compared with 40 eyes of age-matched healthy subjects, the study group showed a significant reduction in the SCP, DCP, and RPC VD. OCTA depicted a more significant impairment of the DCP than the SCP in COVID-19 patients compared to controls, as also occurs in diabetic retinopathy [ 45 ] and other systemic vasculopathy. The authors hypothesise that COVID-19-related thrombotic microangiopathy could cause vascular perfusion damage to the SCP and RPC, resulting in restriction in axoplasmic flow and subsequent retinal structural loss.…”

Evaluation of flow of chorioretinal capillaries in healthy black and white subjects using optical coherence tomography angiography

“…Several studies analyzing microvascular parameters of the SCP, ICP and DCP in patients with diabetic retinopathy found a significant reduction in vessel density across all three distinct capillary plexuses 30 , with the degree of vessel density reduction corresponding to the severity of diabetic retinopathy and associated vision loss 30 – 36 . Recently, the important role of ICP has been distinctly demonstrated with significantly decreased ICP vessel density, perfusion, and blood flow in patients with worsening DR 9 , 31 , 37 .…”