Impaired Retinal Vascular Reactivity in Diabetic Retinopathy as Assessed by Optical Coherence Tomography Angiography

Ashimatey, Bright Senyo; Green, Kyle M; Chu, Zhongdi; Wang, Ke; Kashani, Amir H

doi:10.1167/iovs.18-26417

Cited by 29 publications

(27 citation statements)

References 21 publications

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“…We investigated layer specific RVR during physiologically salient changes in inhaled oxygen and carbon dioxide in diabetic subjects and non-diabetic controls using SS-OCTA. Consistent with our previous findings [19] we found retinal vascular reactivity impairment in diabetic subjects can be assessed with OCTA and show that even in the early stages of the disease the impairment to hypercapnia previously reported are present. Whereas our earlier study consisted entirely of DR subjects with the full range of disease severity, our current cohort of diabetic subjects included only those without DR (68%) or those with mild NPDR.…”

Section: Discussionsupporting

confidence: 93%

“…2017 and February 2020. Approximately, 46% of controls and 36% of diabetics overlapped with those from our previous study by Ashimatey et al [19]…”

Section: Plos Onesupporting

confidence: 68%

“…In order to create conditions of physiological hyperoxia and hypercarbia, a nonrebreathing apparatus was used to deliver gas mixtures. This gas delivery system has been described by Ashimatey et al, [19] and a step by step visual-illustration of the procedure is demonstrated in Kushner-Lenhoff et al [25] In brief, three gas mixtures were delivered through a non-rebreathing gas apparatus to the subjects in the following order during the same visit: room air, a mixture of 5% carbon dioxide, atmospheric oxygen and balanced nitrogen, and finally 100% oxygen. There was a 10-minute refractory period between the hypercapnic and hyperoxic conditions to allow washout of the previous gas condition.…”

Section: Gas Delivery Systemmentioning

confidence: 99%

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Impaired layer specific retinal vascular reactivity among diabetic subjects

et al. 2020

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To investigate layer specific retinal vascular reactivity (RVR) in capillaries of diabetic subjects without DR or with only mild non-proliferative diabetic retinopathy (NPDR). Methods A previously described nonrebreathing apparatus was used to deliver room air, 5% CO 2 , or 100% O 2 to 41 controls and 22 diabetic subjects (with mild or no NPDR) while simultaneously acquiring fovea-centered 3x3mm 2 Swept-Source Optical Coherence Tomography Angiography (SS-OCTA) images. Vessel skeleton density (VSD) and vessel diameter index (VDI) were calculated for each gas condition for the superficial retinal layer (SRL) and deep retinal layer (DRL). The superficial layer analysis excluded arterioles and venules. Data analysis was performed using mixed factorial analysis of covariance stratified by diabetic status. All models were adjusted for age, gender, and hypertension, and statistical significance for multiple comparisons from posthoc comparisons were defined at p<0.017. Results Among controls, there was a significant difference in capillary VSD between all gas conditions (p<0.001). This difference was present in both the SRL and DRL. Among diabetics, there was no significant difference in response to CO 2 conditions in the SRL (p = 0.072), and a blunted response to both CO 2 (p = 0.9) and O 2 in the DRL (p = 0.019). A significant gas effect was detected in the capillary VDI in the SRL of controls (p = 0.001), which was driven by higher VDI in the oxygen condition compared to that of carbon dioxide. Conclusions Impairment in RVR in diabetic subjects is characterized by a paradoxical response to CO 2 in both the SRL and DRL as well as an attenuated response to O 2 in the DRL. These layer and

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Section: Discussionsupporting

confidence: 93%

“…2017 and February 2020. Approximately, 46% of controls and 36% of diabetics overlapped with those from our previous study by Ashimatey et al [19]…”

Section: Plos Onesupporting

confidence: 68%

Section: Gas Delivery Systemmentioning

confidence: 99%

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Impaired layer specific retinal vascular reactivity among diabetic subjects

et al. 2020

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“…42 We found a significantly altered vascular response in subjects with type 1 diabetes before any clinical evidence of diabetic retinopathy. This abnormal retinal microvascular response may correspond to an earlier marker of endothelial dysfunction or changes in the signaling between the retina and the vessels (i.e., neurovascular coupling), 27,43,44 and we provide a novel way of studying it noninvasively using modern OCTA technology.…”

Section: Discussionmentioning

confidence: 99%

Retinal Vascular Reactivity in Type 1 Diabetes Patients Without Retinopathy Using Optical Coherence Tomography Angiography

Sousa

Leal

Moreira

et al. 2020

Invest. Ophthalmol. Vis. Sci.

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We hypothesize that patients with type 1 diabetes (T1D) may have abnormal retinal vascular responses before diabetic retinopathy (DR) is clinically evident. Optical coherence tomography angiography (OCTA) was used to dynamically assess the retinal microvasculature of diabetic patients with no clinically visible retinopathy. METHODS. Controlled nonrandomized interventional study. The studied population included 48 eyes of 24 T1D patients and 24 demographically similar healthy volunteers. A commercial OCTA device (AngioVue) was used, and two tests were applied: (1) the hypoxia challenge test (HCT) and (2) the handgrip test to induce a vasodilatory or vasoconstrictive response, respectively. The HCT is a standardized test that creates a mild hypoxic environment equivalent to a flight cabin. The handgrip test (i.e., isometric exercise) induces a sympathetic autonomic response. Changes in the parafoveal superficial and deep capillary plexuses in both tests were compared in each group. Systemic cardiovascular responses were also comparatively evaluated. RESULTS. In the control cohort, the vessel density of the median parafoveal superficial and deep plexuses increased during hypoxia (F 1,23 = 15.69, P < 0.001 and F 1,23 = 16.26, P < 0.001, respectively). In the T1D group, this physiological response was not observed in either the superficial or the deep retinal plexuses. Isometric exercise elicited a significant decrease in vessel density in both superficial and deep plexuses in the control group (F 1,23 = 27.37, P < 0.0001 and F 1,23 = 27.90, P < 0.0001, respectively). In the T1D group, this response was noted only in the deep plexus (F 1,23 = 11.04, P < 0.01). CONCLUSIONS. Our work suggests there is an early impairment of the physiological retinal vascular response in patients with T1D without clinical diabetic retinopathy.

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“…Neurovascular coupling or functional hyperemia, which describes the adaptation of local perfusion to local changes in neuronal activity [26][27][28] is altered in the diabetic retina [29][30][31][32]. A recent study utilized OCTA to assess the vascular reactivity of retinal capillaries in DR eyes and found a reduced vasoconstriction in response to breathing 100% oxygen [33]. An impaired vascular response to hyperoxia is consistent with the impaired vascular autoregulation in DR.…”

Section: Ocular Vascular Changes In Diabetesmentioning

confidence: 93%

Optical Coherence Tomography Angiography in Diabetes and Diabetic Retinopathy

Chua

Sim

Tan

et al. 2020

JCM

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Diabetic retinopathy (DR) is a common complication of diabetes mellitus that disrupts the retinal microvasculature and is a leading cause of vision loss globally. Recently, optical coherence tomography angiography (OCTA) has been developed to image the retinal microvasculature, by generating 3-dimensional images based on the motion contrast of circulating blood cells. OCTA offers numerous benefits over traditional fluorescein angiography in visualizing the retinal vasculature in that it is non-invasive and safer; while its depth-resolved ability makes it possible to visualize the finer capillaries of the retinal capillary plexuses and choriocapillaris. High-quality OCTA images have also enabled the visualization of features associated with DR, including microaneurysms and neovascularization and the quantification of alterations in retinal capillary and choriocapillaris, thereby suggesting a promising role for OCTA as an objective technology for accurate DR classification. Of interest is the potential of OCTA to examine the effect of DR on individual retinal layers, and to detect DR even before it is clinically detectable on fundus examination. We will focus the review on the clinical applicability of OCTA derived quantitative metrics that appear to be clinically relevant to the diagnosis, classification, and management of patients with diabetes or DR. Future studies with longitudinal design of multiethnic multicenter populations, as well as the inclusion of pertinent systemic information that may affect vascular changes, will improve our understanding on the benefit of OCTA biomarkers in the detection and progression of DR.

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Impaired Retinal Vascular Reactivity in Diabetic Retinopathy as Assessed by Optical Coherence Tomography Angiography

Cited by 29 publications

References 21 publications

Impaired layer specific retinal vascular reactivity among diabetic subjects

Impaired layer specific retinal vascular reactivity among diabetic subjects

Retinal Vascular Reactivity in Type 1 Diabetes Patients Without Retinopathy Using Optical Coherence Tomography Angiography

Optical Coherence Tomography Angiography in Diabetes and Diabetic Retinopathy

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