Morphological changes in and quantitative analysis of macular retinal microvasculature by optical coherence tomography angiography in hypertensive retinopathy

Optical Coherence Tomography Angiography Findings Associated With Accelerated Hypertension

Introduction Accelerated hypertension, that is a systolic blood pressure greater than 180 mmHg and a diastolic blood pressure greater than 120 mmHg is often accompanied by fundoscopic signs with the potential of systemic and visual morbidity. We report on the clinical and optical coherence tomography angiography (OCTA) findings in a cohort of hypertensive patients with accelerated hypertension. Methods Patients, presenting to the emergency room/intensive care unit, who met the clinical definition of accelerated hypertension (a blood pressure >180/120 mmHg,), were triaged to the intensive care unit. Following blood pressure reduction via pharmacological methods, a standard panel of hematological tests, cardiac evaluation tests, and the necessary systemic imaging was performed. They underwent a bedside dilated fundus examination with subsequent fundus photography/OCTA using a Topcon DRI OCT plus (Topcon Corporation, Tokyo, Japan). The records of these patients were evaluated. Results We analyzed the records of 16 patients (12 males (75%), and four females (25%)) with ages ranging from 16 to 75 years (mean 47.6 years). Eleven patients consented to a detailed evaluation. These included nine males (81.8%) and two females (18.1%) with ages ranging from 16 to 63 years (mean 46.3 years). Comorbidities included pre-existing hypertension (nine patients, 81.8%), chronic kidney disease (three patients, 27.2%), and diabetes mellitus type 2 (two patients, 18.1%). Clinical findings in these 22 eyes included arteriolar changes consistent with Keith Wagener Barker (KWB) grade 1 (two eyes, 9.0%), grade 2 (10 eyes, 45.4%), grade 3 (eight eyes, 36.3%), and grade 4 (two eyes, 9.0%). OCTA findings included capillary nonperfusion in the superficial capillary plexus in the areas of retinal opacification (seven eyes, 31.8%). Conclusion OCTA studies of the macular, as well as the entire posterior pole vasculature, may help to detect retinal microangiopathy, permit accurate grading, and subsequently develop a model that permits the quantification of systemic and ocular risk in these patients.

Macular Microvascular Perfusion Status in Hypertensive Patients with Chronic Kidney Disease

To compare retinal microvascular perfusion between the eyes of hypertensive patients with and without chronic kidney disease (CKD), the vessel density (VD) and fractal dimension (FD) of the superficial (SVP) and deep retinal vascular plexus (DVP) were analyzed on 6 × 6 mm fovea-centered optical coherence tomography angiography (OCTA) images of patients with hypertension. The retina was divided into an inner ring (IR) and outer ring (OR) according to the Early Treatment of Diabetic Retinopathy Study grid. The glomerular filtration rate (GFR) was determined and CKD was diagnosed (GFR < 60 mL/min/1.73 m2). Ninety-six eyes from 52 patients with hypertension were included in this analysis. Twenty patients (n = 37 eyes) were diagnosed with CKD. The mean age was 69 ± 11.7 years and 60.4 ± 9.2 years in the CKD group and in the control group, respectively. The univariate model revealed a significant difference in VD between patients without and with CKD in the superficial IR (0.36 ± 0.03 vs. 0.34 ± 0.04, p = 0.03), the superficial OR (0.35 ± 0.02 vs. 0.33 ± 0.04, p = 0.02), the deep OR (0.24 ± 0.01 vs. 0.23 ± 0.02, p = 0.003), and the FD in the SVP (1.87 ± 0.01 vs. 1.86 ± 0.02, p = 0.02) and DVP (1.83 ± 0.01 vs. 1.82 ± 0.01, p = 0.006). After adjusting for age and sex, these differences did not remain statistically significant. Similar results were observed for the FD in the SVP and DVP. In our cohort, patients with hypertension and CKD did not differ from patients without CKD in regard to microvascular perfusion status in the macular area as assessed using OCTA.

[Less Frequent Vascular Disorders of the Retina - Part 1]

This review provides an overview of retinal vascular disorders that are less frequent in Germany and Europe compared to diabetic retinopathy and retinal venous or arterial occlusive disorders. The knowledge of these disorders is important for the differential diagnosis of retinal vascular disorders as well as potentially associated systemic disorders. In the current part one epidemiology, pathophysiology, clinical presentation, and therapy are discussed for hypertensive retinochoroidopathy, ocular ischemic syndrome, retinal alterations in sickle cell disease, Eales disease, radiation retinopathy, peripheral exudative hemorrhagic chorioretinopathy, and retinal disorders associated with pregnancy.

Research progress on diagnosing retinal vascular diseases based on artificial intelligence and fundus images

As the only blood vessels that can directly be seen in the whole body, pathological changes in retinal vessels are related to the metabolic state of the whole body and many systems, which seriously affect the vision and quality of life of patients. Timely diagnosis and treatment are key to improving vision prognosis. In recent years, with the rapid development of artificial intelligence, the application of artificial intelligence in ophthalmology has become increasingly extensive and in-depth, especially in the field of retinal vascular diseases. Research study results based on artificial intelligence and fundus images are remarkable and provides a great possibility for early diagnosis and treatment. This paper reviews the recent research progress on artificial intelligence in retinal vascular diseases (including diabetic retinopathy, hypertensive retinopathy, retinal vein occlusion, retinopathy of prematurity, and age-related macular degeneration). The limitations and challenges of the research process are also discussed.

Hypertensive eye disease

Hypertensive eye disease includes a spectrum of pathological changes, the most well known being hypertensive retinopathy. Other commonly involved parts of the eye in hypertension include the choroid and optic nerve, sometimes referred to as hypertensive choroidopathy and hypertensive optic neuropathy. Together, hypertensive eye disease develops in response to acute and/or chronic elevation of blood pressure. Major advances in research over the past three decades have greatly enhanced our understanding of the epidemiology, systemic associations and clinical implications of hypertensive eye disease, particularly hypertensive retinopathy. Traditionally diagnosed via a clinical funduscopic examination, but increasingly documented on digital retinal fundus photographs, hypertensive retinopathy has long been considered a marker of systemic target organ damage (for example, kidney disease) elsewhere in the body. Epidemiological studies indicate that hypertensive retinopathy signs are commonly seen in the general adult population, are associated with subclinical measures of vascular disease and predict risk of incident clinical cardiovascular events. New technologies, including development of non-invasive optical coherence tomography angiography, artificial intelligence and mobile ocular imaging instruments, have allowed further assessment and understanding of the ocular manifestations of hypertension and increase the potential that ocular imaging could be used for hypertension management and cardiovascular risk stratification.

The New Era of Retinal Imaging in Hypertensive Patients

ABSTRACT

Structural and functional alterations in the microcirculation by systemic hypertension can cause significant organ damage at the eye, heart, brain, and kidneys. As the retina is the only tissue in the body that allows direct imaging of small vessels, the relationship of hypertensive retinopathy signs with development of disease states in other organs have been extensively studied; large-scale epidemiological studies using fundus photography and advanced semi-automated analysis software have reported the association of retinopathy signs with hypertensive end-organ damage includes the following: stroke, dementia, and coronary heart disease. Although yielding much useful information, the vessels assessed from fundus photographs remain limited to the larger retinal arterioles and venules, and abnormalities observed may not be that of the earliest changes. Newer imaging modalities such as optical coherence tomography angiography and adaptive optics technology, which allow a greater precision in the structural quantification of retinal vessels, including capillaries, may facilitate the assessment and management of these patients. The advent of deep learning technology has also augmented the utility of fundus photographs to help create diagnostic and risk stratification systems. Particularly, deep learning systems have been shown in several large studies to be able to predict multiple cardiovascular risk factors, major adverse cardiovascular events within 5 years, and presence of coronary artery calcium, from fundus photographs alone. In the future, combining deep learning systems with the imaging precision offered by optical coherence tomography angiography and adaptive optics could pave way for systems that are able to predict adverse clinical outcomes even more accurately.

Quantifying the pattern of retinal vascular orientation in diabetic retinopathy using optical coherence tomography angiography

Quantitative imaging using optical coherence tomography angiography (OCTA) could provide objective tools for the detection and characterization of diabetic retinopathy (DR). In this study, an operator combining the second derivative and Gaussian multiscale convolution is applied to identify the retinal orientation at each pixel in the OCTA image. We quantified the pattern of retinal vascular orientation and developed three novel quantitative metrics including vessel preferred orientation, vessel anisotropy, and vessel area. Each of eight 45º sectors of the circular disk centered at the macular region was defined as the region of interest. Significant sectoral differences were observed in the preferred orientation (p < 0.0001) and vessel area (p < 0.0001) in the 34 healthy subjects, whereas vessel anisotropy did not demonstrate a significant difference among the eight sectors (p = 0.054). Differential retinal microvascular orientation patterns were observed between healthy controls (n = 34) and the DR subjects (n = 7). The vessel area characterized from the vascular orientation pattern was shown to be strongly correlated with the traditionally reported vessel density (Pearson R > 0.97, p < 0.0001). With three metrics calculated from the vascular orientation pattern simultaneously and sectorally, our quantitative assessment for retinal microvasculature provides more information than vessel density alone and thereby may enhance the detection of DR. These preliminary results suggest the feasibility and advantage of our vessel orientation-based quantitative approach using OCTA to characterize DR-associated changes in retinal microvasculature.