Quantitative Microvascular Change Analysis Using a Semi-Automated Algorithm in Macula-on Rhegmatogenous Retinal Detachment Assessed by Swept-Source Optical Coherence Tomography Angiography

PURPOSE

The purpose of this study was to objectively evaluate the longitudinal changes observed in the retinal capillaries in eyes with macula-on rhegmatogenous retinal detachment (RRD), assessed with optical coherence tomography angiography (OCTA), and to assess the role of these microvascular measures as potential biomarkers of postoperative visual outcomes.

METHODS

This was a prospective, longitudinal study conducted on consecutive patients who underwent 25 G pars plana vitrectomy for primary RRD. The vessel area density (VAD), vessel skeleton density (VSD), and vessel diameter index (VDI) were assessed in the superficial (SCP) and deep (DCP) capillary plexuses.

RESULTS

Twenty-three eyes with macula-on RRD were included in the study. The mean preoperative VDI, VAD, and VSD of the RRD eye were 18.6 ± 1.1, 0.43 ± 0.02, and 0.17 ± 0.01 in the SCP; and 18.6 ± 0.6, 0.38 ± 0.03, and 0.15 ± 0.01 in the DCP, respectively. At month 6, eight (34.8%) eyes achieved a best-corrected visual acuity (BCVA) gain ≥ 0.1 LogMAR. A preoperative VDI > 17.80, VSD > 0.170, and VDI-change > -0.395 in the SCP; and VDI > 18.11 and VDI change > -0.039 in the DCP were predictors of achieving a BCVA-gain ≥ 0.1 LogMAR.

CONCLUSIONS

The preoperative VDI in SCP and DCP, the preoperative VSD in SCP, and their changes from preoperative values were predictors of visual outcomes. A quantitative OCTA analysis of capillary density and morphology may represent a potential predictive tool for surgical outcomes in RRD. The results reported in this study suggest that OCTA is a useful ancillary test for clinical disease management.

Microvascular Changes Are Associated with Proteinuria and EMG Changes in Patients with Type 2 Diabetes Using Video Capillaroscopy

Objectives: Video capillaroscopy is a diagnostic method for evaluating microvascular changes in type 2 diabetes mellitus (T2DM). This study evaluated microvascular changes, including microvascular architecture, capillary distribution (morphology and density), and angiogenesis conditions in T2DM patients via video capillaroscopy. Methods: A total of 256 patients with T2DM enrolled in this study. Based on electromyography (EMG)-nerve conduction velocity results, patients were divided into patients with normal and abnormal EMG. Microalbuminuria was assessed using biochemical urine analysis. Finally, video capillaroscopy was performed to evaluate changes in microvascular architecture, capillary distribution, and angiogenesis status. Results: The differences between microalbuminuria in patients with normal and abnormal EMG were not significant. Other microvascular changes were not significant between normal and abnormal EMG groups. The patients with greater microalbuminuria were at risk of abnormal EMG 2.8 times higher than those with fewer microalbuminuria (odds ratio = 2.804; 1.034-7.601). However, EMG is not a risk factor for microvascular architecture alternation in T2DM (odds ratio = 1.069; 0.323-3.546). Conclusions: Microvascular alternations are common in T2DM and early detection of these changes could help to avoid the progress of nephropathic complications. Also, video capillaroscopy provides a promising diagnostic method for the detection of microvascular alternations in T2DM.

Microvascular changes after pars plana vitrectomy for rhegmatogenous retinal detachment repair: A comparative study based on gas tamponade agent

PURPOSE

The purpose of this study was to investigate the effect of gas tamponade on microvascular changes in patients with rhegmatogenous retinal detachment (RRD), who underwent pars plana vitrectomy (PPV), using optical coherence tomography angiography (OCTA).

METHODS

Participants in this study were 48 patients with RRD, who were treated with PPV and gas tamponade without internal limiting membrane peeling. All participants underwent slit-lamp examination, fundoscopy, spectral domain-optical coherence tomography and optical coherence tomography angiography at month 6 postoperatively. The fellow untreated eyes were also examined and served as the control data.

RESULTS

A statistically significant enlargement in the foveal avascular zone (FAZ) in both the superficial (p = 0.002) and the deep capillary plexus (p = 0.01) was noticed 6 months postoperatively in patients with RRD treated with PPV compared to the fellow eyes. The foveal avascular zone perimeter was increased in the operated eyes in the deep capillary plexus (p = 0.0003) and the foveal avascular zone circularity was decreased in both the superficial (p = 0.045) and the deep capillary plexus (p < 0.001) compared to the fellow eyes. The vessel density was not significantly different between the operated and the fellow eyes in the superficial and the deep capillary plexus. The vessel density and the foveal avascular zone parameters were comparable between the C3F8 and SF6 groups.

CONCLUSION

Specific microvascular indices as measured by OCTA were statistically different between the operated and the fellow eyes in the superficial and deep capillary plexus. C3F8 and SF6 as gas tamponades did not seem to differ in their impact on the microvascular parameters.

RETINAL VASCULAR DENSITY CHANGE IN PATIENTS WITH HEART FAILURE

PURPOSE

The aim of this study is to assess choroid thickness, retinal vessel density in the superficial capillary plexus layer and deep capillary plexus layer in heart failure (HF) using optical coherence tomography angiography (OCT-A).

METHODS

36 healthy participants (group 1), 33 patients with HF were assessed for this study. HF patients had a left ventricular ejection fraction (LVEF) <50%. HF patients were divided into 2 groups according to the New York Heart Association (NYHA). 15 patients were evaluated as group 2 according to NYHA and 18 patients as group 3 according to NYHA. Choroid thickness, superficial and deep capillary plexus perfusion were analyzed between groups using OCT-A.

RESULTS

Choroid thicknesses were found to be significantly decrease in the HF groups. Superficial capillary plexus density was compared with the control group, no statistically significant difference was found between the HF groups. But among the HF groups, a statistically significant decrease was found in group 3 patients. Deep capillary plexus density was compared with the control group, a statistically significant decrease was found in group 3. In addition, deep capillary plexus density a statistically significant difference was found between the groups HF.

CONCLUSIONS

Patients with HF showed decreased flow density compared with healthy controls. In addition, significant changes were found in flow densities among the HF groups. Retinal perfusion measured using OCT-A may give an idea about the hemodynamic status and microperfusion of HF patients.

Association of Retinal Age Gap and Risk of Kidney Failure: A UK Biobank Study

RATIONALE & OBJECTIVE

The incidence of kidney failure is known to increase with age. We have previously developed and validated the use of retinal age based on fundus images as a biomarker of aging. However, the association of retinal age with kidney failure is not clear. We investigated the association of retinal age gap (the difference between retinal age and chronological age) with future risk of kidney failure.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

11,052 UK Biobank study participants without any reported disease for characterizing retinal age in a deep learning algorithm. 35,864 other participants with retinal images and no kidney failure were followed to assess the association between retinal age gap and the risk of kidney failure.

EXPOSURE

Retinal age gap, defined as the difference between model-based retinal age and chronological age.

OUTCOME

Incident kidney failure.

ANALYTICAL APPROACH

A deep learning prediction model used to characterize retinal age based on retinal images and chronological age, and Cox proportional hazards regression models to investigate the association of retinal age gap with incident kidney failure.

RESULTS

After a median follow-up period of 11 (IQR, 10.89-11.14) years, 115 (0.32%) participants were diagnosed with incident kidney failure. Each 1-year greater retinal age gap at baseline was independently associated with a 10% increase in the risk of incident kidney failure (HR, 1.10 [95% CI, 1.03-1.17]; P=0.003). Participants with retinal age gaps in the fourth (highest) quartile had a significantly higher risk of incident kidney failure compared with those in the first quartile (HR, 2.77 [95% CI, 1.29-5.93]; P=0.009).

LIMITATIONS

Limited generalizability related to the composition of participants in the UK Biobank study.

CONCLUSIONS

Retinal age gap was significantly associated with incident kidney failure and may be a promising noninvasive predictive biomarker for incident kidney failure.

Long-Term Follow-Up of Macular Perfusion Evaluated by Optical Coherence Tomography Angiography after Rhegmatogenous Retinal Detachment Surgery

BACKGROUND

The goal of this study was to investigate macular microvascular changes using optical coherence tomography angiography (OCTA) at one year after successful rhegmatogenous retinal detachment (RRD) surgery.

METHODS

We performed a cross-section study including RRD treated by pars plana vitrectomy (PPV) with or without scleral buckling and SF6 tamponade. After 12 months, DRI-Triton SS-OCTA was performed. Superficial and deep retinal capillary plexuses (SCP and DCP), choriocapillaris (CC) vessel density (VD), and foveal avascular zone (FAZ) morphology were analyzed. Results were compared with the unaffected contralateral eye.

RESULTS

Sixty eyes were included. We observed an increase in VD in the central area of both the SCP and DCP in macula-off eyes treated with PPV + SB and in the SCP of macula-off eyes treated with PPV. Macula-off eyes had a diminished VD for both plexuses in the superior quadrant and in the SCP inferior quadrant in those treated with PPV + SB. The CC flow was diminished in the temporal quadrant of macular-off eyes treated with PPV + SB. Healthy eyes presented higher diameter values than macula-off eyes treated with PPV + SB. FAZ horizontal and vertical diameters were smaller in patients with macula-off RRD vs. macula-on RRD and control groups.

CONCLUSION

Macular vascularity remains almost unchanged one year after successful RRD surgery, irrespective of the surgical technique or prior macular status.

The Longitudinal Assessment of Vascular Parameters of the Retina and Their Correlations with Systemic Characteristics in Type 2 Diabetes-A Pilot Study

The aim of the study was to assess various retinal vessel parameters of diabetes mellitus (DM) patients and their correlations with systemic factors in type 2 DM. A retrospective exploratory study in which 21 pairs of baseline and follow-up images of patients affected by DM were randomly chosen from the Sankara Nethralaya−Diabetic Retinopathy Study (SN DREAMS) I and II datasets. Patients’ fundus was photographed, and the diagnosis was made based on Klein classification. Vessel thickness parameters were generated using a web-based retinal vascular analysis platform called VASP. The thickness changes between the baseline and follow-up images were computed and normalized with the actual thicknesses of baseline images. The majority of parameters showed 10~20% changes over time. Vessel width in zone C for the second vein was significantly reduced from baseline to follow-up, which showed positive correlations with systolic blood pressure and serum high-density lipoproteins. Fractal dimension for all vessels in zones B and C and fractal dimension for vein in zones A, B and C showed a minimal increase from baseline to follow-up, which had a linear relationship with diastolic pressure, mean arterial pressure, serum triglycerides (p < 0.05). Lacunarity for all vessels and veins in zones A, B and C showed a minimal decrease from baseline to follow-up which had a negative correlation with pulse pressure and positive correlation with serum triglycerides (p < 0.05). The vessel widths for the first and second arteries significantly increased from baseline to follow-up and had an association with high-density lipoproteins, glycated haemoglobin A1C, serum low-density lipoproteins and total serum cholesterol. The central reflex intensity ratio for the second artery was significantly decreased from baseline to follow-up, and positive correlations were noted with serum triglyceride, serum low-density lipoproteins and total serum cholesterol. The coefficients for branches in zones B and C artery and the junctional exponent deviation for the artery in zone A decreased from baseline to follow-up showed positive correlations with serum triglycerides, serum low-density lipoproteins and total serum cholesterol. Identifying early microvascular changes in diabetic patients will allow for earlier intervention, improve visual outcomes and prevent vision loss.

[Optical coherence tomography angiography in the diagnosis of retinal microvascular changes in chronic kidney disease (clinical observations)]

One distinctive pathological sign of chronic kidney disease (CKD) is microcirculatory disorders, which mark it as a microvascular disease. Similarity in the blood supply of the retina and kidneys, in the anatomy of their vascularization lead to identical complications in these organs. The retinal-choroidal microvascular system is easily accessible for clinical and morphological assessment and can be examined by the reproducible and non-invasive method - optical coherence tomography (OCT) and OCT angiography (OCTA). The study of significant diagnostic tomographic retinal biomarkers in CKD and monitoring of their changes are of great clinical importance. The article presents clinical cases of changes in the retina and choroid depending of the stage of CKD. Retinal microvascular changes precede functional impairment. A significant decrease in retinal and choroidal thickness correlates with a decrease in the glomerular filtration rate (GFR) and the degree of albumin excretion in the urine. All clinical cases were observed to exhibit retinal microcirculation disorders, capillary rarefaction in both capillary plexuses accompanied by a decrease in vessel density and a decrease in the circularity index of the foveal avascular zone as a result of regression of the parafoveal capillary networks. OCTA allowed visualization of morphological changes at the microcirculatory level in the form of blunt ends of capillaries, their increased tortuosity and the presence of local areas of decreased perfusion. The severity of retinal microvascular changes varied depending on the stage of CKD and was not associated with either age or the presence of diabetes mellitus. Assessment of the retinal microvasculature can help with monitoring of microvascular lesions, early prediction of the risk of development and progression of decreased renal function, as well as allow avoiding aggressive diagnostic biopsy.

TuYou-County Pediatric Eye (TYPE) study, design issues, baseline demographic characteristics, and implications: Report number 1

To report the rationale, design, and baseline demographic characteristics of TuYou-County Pediatric Eye study, which mainly aimed to determine the retinal microvascular changes with optical coherence tomography angiography (OCTA) and its association with eye abnormalities in school aged children and adolescents at suburban location in Northern China.TuYou-County Pediatric Eye study was a school-based survey conducted in TuYou-County. Multi-ethnic (Mongol, Han, and Hui) participants will be followed up for 5 years. Standardized ophthalmological examinations include visual acuity, ocular biometry, retinal photography, and OCTA. A questionnaire survey was conducted to collect variables regarding to eye disease such as parental history of eye diseases, near work, outdoor activities, living and eating habits, etc.After sampling, 687 participants were eligible for investigation, and 20 students did not attend the investigation, living 667 (response rate, 97.1%) students completed questionnaires and all ocular examinations. The average age of all participants was 14.9 ± 5.11.TYPE study is the first large-scale school-based multi-ethnic survey in suburban site of Northern China. Continuous identification of retinal microvascular changes with eye diseases will provide new insights into the control related diseases in school-age children and adolescents.

[Development, clinical manifestations and diagnosis of retinal changes in chronic kidney disease]

Chronic kidney disease (CKD) is a significant public health problem with a high risk of developing age-dependent eye diseases. Renal glomeruli and the choroid have similar structures and vascular networks; the internal hematoretinal barrier and the glomerular filtration barrier have similar developmental path; the renin-angiotensin-aldosterone hormonal system is found in both the eye and the kidneys. All this determines the similarity of physiological and pathogenetic features of the development of diseases associated with these organs. The article discusses general risk factors and pathophysiological mechanisms of development of retinal and renal lesions in CKD, the influence of various factors of pathogenesis on their development and progression. The anatomical similarity of vascularization, accompanied by microvascular changes in the retina and kidneys, leads to similar complications in both organs. Optical coherence tomography (OCT) and optical coherence tomography angiography (OCT-A) are accurate, well reproducible and non-invasive methods for diagnosing and assessing changes in the retinal microvascular bed, which make it possible to assess microvasculature changes in the kidneys. In CKD, the retina shows signs of impaired capillary perfusion, a decrease in their density, expansion of intercapillary spaces, a rarefaction of the density of the parafoveolar capillary network, which may indicate a decrease in peritubular capillary blood flow, blood circulation of the kidneys in general and their ischemia. Significant thinning of the retina and choroid, along with a decrease in macular volume, even in the initial stages of CKD, is accompanied by impaired renal function (changes in the estimated glomerular filtration rate and urinary albumin excretion), which is a sign of systemic microvascular lesion and pathological process in the kidneys. Therefore, monitoring of retinal vessels using OCT and OCT-A can become a reliable indicator of the progression of renal microvascular changes at any stage of the disease.

Retinal Microvasculature Changes After Repair of Macula-off Retinal Detachment Assessed with Optical Coherence Tomography Angiography

Objective

To characterize the microvascular retinal changes after repair of macula-off rhegmatogenous retinal detachment (RRD) using optical coherence tomography angiography (OCT-A).

Patients and Methods

A retrospective review of patients who underwent repair of macula-off RRD. Fellow unaffected eyes were used as controls. Post-operative OCT-A allowed comparison of vessel density (VD) and foveal avascular zone (FAZ) area in the superficial and deep retinal capillary plexus (DCP) as well as VD in the choriocapillaris layer.

Results

Seventeen eyes of 17 RRD patients were included in the final analysis. There was a reduction in VD of the deep retinal capillary plexus in affected eyes compared to fellow eyes (p = 0.046). RRD eyes with reduced VD in DCP compared with their fellow control eyes had worse visual acuity after repair compared to those without (p = 0.032). No significant microvasculature changes were detected in the FAZ area and VD in the superficial capillary plexus and choriocapillaris compared to fellow eyes.

Conclusion

In macula-off RRD eyes, significant microvascular changes were detected in the DCP using OCT-A even after successful anatomical repair. Decreased VD in the DCP compared to the fellow healthy eyes was correlated with worse visual acuity.

Non-invasive monitoring of pharmacodynamics during the skin wound healing process using multimodal optical microscopy

OBJECTIVE

Impaired diabetic wound healing is one of the serious complications associated with diabetes. In patients with diabetes, this impairment is characterized by several physiological abnormalities such as metabolic changes, reduced collagen production, and diminished angiogenesis. We designed and developed a multimodal optical imaging system that can longitudinally monitor formation of new blood vessels, metabolic changes, and collagen deposition in a non-invasive, label-free manner.

RESEARCH DESIGN AND METHODS

The closure of a skin wound in (db/db) mice, which presents delayed wound healing pathologically similar to conditions in human type 2 diabetes mellitus, was non-invasively followed using the custom-built multimodal microscope. In this microscope, optical coherence tomography angiography was used for studying neovascularization, fluorescence lifetime imaging microscopy for nicotinamide adenine dinucleotide (phosphate) (NAD(P)H) assessment, fluorescence intensity changes of NAD(P)H and flavin adenine dinucleotide (FAD) cofactors for evaluating metabolic changes, and second harmonic generation microscopy for analyzing collagen deposition and organization. The animals were separated into four groups: control, placebo, low concentration (LC), and high concentration (HC) treatment. Images of the wound and surrounding areas were acquired at different time points during a 28-day period.

RESULTS

Various physiological changes measured using the optical imaging modalities at different phases of wound healing were compared. A statistically significant improvement in the functional relationship between angiogenesis, metabolism, and structural integrity was observed in the HC group.

CONCLUSIONS

This study demonstrated the capability of multimodal optical imaging to non-invasively monitor various physiological aspects of the wound healing process, and thus become a promising tool in the development of better diagnostic, treatment, and monitoring strategies for diabetic wound care.

A patient-centered approach to the burden of symptoms in patients with scleroderma treated with Bosentan: A prospective single-center observational study

Systemic sclerosis (SSc) is a rare and complex autoimmune disease associated with poor vital and functional outcomes. The functional hindrance in patients derives from various disease-specific manifestations, including Raynaud's phenomenon and digital ulcers (DUs). Bosentan is an endothelin receptor antagonist capable of preventing the appearance of new DUs in patients with scleroderma. The present study aimed to evaluate the effects of Bosentan on the severity of Raynaud's phenomenon, DU-related symptoms and functional impairment during the first year of treatment. A prospective study that included adult patients with SSc admitted to the Rheumatology Department between January 2016 and January 2017 that were candidates for Bosentan therapy, was performed. All patients were asked to evaluate the burden of symptoms secondary to Raynaud's and DUs using a visual analogue scale (VAS), whereas functional hindrance was assessed via Health Assessment Questionnaire Disability Index (HAQ-DI). The outcomes were assessed at baseline and every 3 months during 1 year of therapy. Among the 41 patients included initially, 2 participants discontinued the treatment after 1 month due to adverse events (elevation of liver enzymes). The study cohort exhibited a significant improvement in HAQ-DI, VAS-R and VAS-DU scores in response to Bosentan therapy over the 1-year follow-up period. Higher scores at baseline predicted a weaker treatment-related improvement, with the risk of a poor outcome being increased by 220% for VAS-R, 116% for VAS-DU, whereas no increase was observed for HAQ-DI. The post-treatment improvement in VAS-DU levels was associated with a better outcome for HAQ-DI (R=0.44; P=0.005). This association was not identified for VAS-R (R=0.24; P=0.137). Throughout the follow-up period, patients with dyspnea presented with significantly higher HAQ-DI scores compared with non-dyspneic patients. Bosentan therapy may indirectly influence functionality and quality of life in patients with scleroderma by reducing the burden of Raynaud's and DU-related symptoms. Nonetheless, patients with SSc with a decreased symptom burden at baseline exhibited improved outcomes.

Microvascular Changes Associated with Optic Disc Drusen: Case Report

Optic disc drusen (ODD) is an important clinical entity that is sometimes misdiagnosed as papilledema because of elevated and blurred disc margins. A 17-year-old male who presented with headaches underwent detailed ophthalmological examination as well as colored fundus photography, B-scan ultrasonography (USG), fundus autofluorescence (FAF), optical coherence tomography (OCT), optical coherence tomography angiography (OCTA), and visual field testing. His visual acuity was 10/10 in both eyes. Fundus examination revealed bilateral blurred and elevated optic disc margins. Diagnosis of bilateral ODD was confirmed with B-scan USG. FAF imaging revealed hyperautofluorescent areas on both optic discs. Optic nerve head OCT scans showed elevated irregular disc borders and thinning of the retinal nerve fiber layer in both eyes. On visual field testing, loss of the nasal visual field was detected in the left eye. OCTA imaging showed focal capillary dropout, especially in the nasal peripapillary area, in both eyes and reduced peripapillary and macular vessel density. In this case report, we evaluated the clinical findings and the structural features of bilateral ODD with multimodal imaging modalities including OCTA.

The role of nailfold videocapillaroscopy in patients with systemic sclerosis

Systemic sclerosis (SSc) is a complex disease which consists of autoimmunity, fibrosis and vasculopathy. Most organ involvement in SSc patients is related to progressive fibrosis. Once fibrosis progresses, it becomes impossible to maintain a normal structure histologically. Therefore, treatment in cases with advanced fibrosis is quite difficult. On the other hand, the role of vasculopathy is clear in the pathogenesis of SSc. Lethal organ disorders of SSc, such as pulmonary arterial hypertension and scleroderma renal crisis, include severe signs of advanced vasculopathy. Nailfold videocapillaroscopy (NVC) is a safe and crucial method for evaluating microvasculopathy. The morphological changes and their progressions can be detected and scored by NVC. Indeed, the microvascular damage and dysfunction represent early markers of systemic sclerosis. Systemic sclerosis has clinical heterogeneity and the use of NVC has been validated to help with early diagnosis and even treatment. Finally, NVC may be useful in evaluating the pathogenesis of systemic sclerosis and its progression in connection with other early biomarkers and functional tools.

The evaluation of nailfold videocapillaroscopy findings in patients with type 2 diabetes with and without diabetic retinopathy

OBJECTIVE:

Diabetes mellitus (DM) is a chronic hyperglycemic state and is associated with microvascular structural alterations. This study aimed to investigate the diameters of capillary loops and morphostructural changes using nailfold video capillaroscopy (NVC) in patients with type 2 DM with and without diabetic retinopathy (DR).

METHODS:

This cross-sectional, single-center study was conducted in patients with type 2 DM who were followed in outpatient clinics of ophthalmology and internal medicine. General demographic data were collected from patients. An ophthalmologist examined all patients in terms of DR. A rheumatologist blinded to the clinical data performed NVC. The diameters of apical, arterial, and venous loop of capillaries were measured, and the microvascular changes of capillaries were scored.

RESULTS:

In this study, 44 patients with type 2 DM with DR (47.7% males) and 20 patients with type 2 DM without DR (55% males) were included. In our study, patients with type 2 DM with DR had more frequent capillary hemorrhage, more frequent ectasia, more frequent giant capillary, and more frequent neo-angiogenesis than patients with type 2 DM without DR. However, these findings were not statistically significant.

CONCLUSION:

Further controlled studies with large sample size are needed to determine the characteristic NVC findings of DR in patients with type 2 DM.