Features of vascular-platelet and coagulation hemostasis in relation to parameters of macular blood fl ow in women with preeclampsia

Background. Recently, more and more attention has been paid to the development of vascular retinal disorders after suffering preeclampsia. It is noted that the key role in this process is assigned to the systemic endothelial dysfunction that persists for a long time after delivery.Aim: to elucidate the features of vascular-platelet and coagulation hemostasis in relation to the indicators of blood flow in the macular region in women with preeclampsia.Materials and methods. The main group included 45 women with preeclampsia in the third trimester of pregnancy (35–36 weeks). Their age ranged from 19 to 40 years (27 ± 5.2 years). The comparison group was represented by 20 women with physiological pregnancy in the third trimester (35–36 weeks). Their age averaged 26 ± 5.1 years (18–38 years). Somatically healthy non-pregnant women (20 people) were included in the control group. Their age ranged from 19 to 38 years (26 ± 5.4 years). A comparative analysis of the studied parameters of macular blood fl ow, vascular-platelet and coagulation hemostasis between the groups was carried out.Results. When studying the number of platelets in pregnant women, it turned out that in patients with preeclampsia, this indicator was statistically signifi cantly lower compared to the comparison and control groups (p < 0.05). The level of fi brinogen in women with complicated pregnancies was statistically significantly higher than in women with physiological pregnancy and in somatically healthy nonpregnant women (p < 0.05). In addition, retinal microcirculation disorders were observed in women of the main group.Conclusions. The revealed disorders of vascular-platelet and coagulation hemostasis in women during the period of complicated pregnancy were accompanied by disorders of macular blood fl ow in the form of a decrease in the total average density of vessels in the superfi cial vascular plexus, subfoveolar thickness of the choroid and an increase in the area of the avascular zone relative to the group of women with physiological pregnancy and somatically healthy nonpregnant women.

Daytime napping is associated with retinal microcirculation: a large population-based study in China

Study Objectives To investigate the association between daytime napping and retinal microcirculation. Methods This is a cross-sectional study from a prospective population-based cohort. 2,662 participants were recruited after quota sampling. Information on napping was collected through face-to-face interviews. Retinal vascular calibers (RVCs), including central retinal arteriolar equivalent (CRAE), central retinal venular equivalent (CRVE), and arterio-to-venous ratio (AVR), were obtained from fundus photography. Multivariate regression and restricted cubic spline curve were performed to determine the association between RVCs and daytime napping duration. Results 56.4% participants reported daytime napping regularly. Compared to no nap, daytime nap was related to higher CRAE, with nap duration of 0.5–1 h showing the most significant association. 0.5–1 h daytime nappers displayed an average of 4.18 µm (95% confidence interval [CI] 2.45–5.91, p &lt; 0.001) wider CRAE than non-nappers after adjustment. No significant association was found between CRVE and daytime napping. Moreover, individuals with 0.5–1 h daytime napping had a lower risk for AVR reduction (odds ratio [OR] 0.70, 95% confidence interval [CI] 0.56–0.86, p = 0.001) than non-nappers. Similar association persisted in non-hypertensive population. Restricted cubic spline indicated a J-shaped relationship between AVR reduction and nap duration. Conclusion Retinal microcirculation was positively associated with self-reported 0.5–1 h daytime napping. Better indicators of retinal microcirculation were probably related to nap duration in a J-shaped manner. Also, the possibly beneficial role of 0.5–1 h daytime napping on retinal microcirculation might be independent of clinically diagnosed vascular diseases.

The Impact of Coronavirus Disease 2019 (COVID-19) on Retinal Microcirculation in Human Subjects

Background The aim of the study was to assess retinal microcirculation in patients with coronavirus disease 2019 (COVID-19) through the use of optical coherence tomography angiography (OCT-A) and compare the results with those obtained in healthy controls. Methods The study enrolled 39 patients who had fully recovered from COVID-19 and 40 healthy controls. OCT-A image acquisitions were obtained using AngioVue software (version 2017.1.0.151) and the RTVue XR Avanti imaging system (Optovue Inc., Fremont, CA, USA). Nonflow area in the superficial capillary plexus (SCP), foveal avascular zone (FAZ) area in the whole retinal vasculature, FAZ perimeter, acircularity index of FAZ, and foveal density were automatically obtained with the FAZ assessment tool. Vessel density (VD) at the SCP and deep capillary plexus were also measured. Results Compared to the control group, the nonflow area and the FAZ area in the whole retina was greater in the COVID-19 group; however no statistically significant difference was observed (p > 0.05 respectively). As for vessel densities, all superficial parafoveal VD parameters were considerably higher in the COVID-19 group compared to the control group (p < 0.05 respectively). Despite the fact that the vessel densities in the remaining zones were lower in the COVID-19 group, those differences were not statistically significant (p > 0.05 respectively). Conclusion VD at the parafoveal area of the SCP was significantly higher among patients in the late post-recovery period of COVID-19 disease compared to healthy controls. These findings show the impact of COVID-19 on the retinal microvasculature and its possible role as a risk factor for the development of ocular diseases.

Metabolic Signaling in a Theoretical Model of the Human Retinal Microcirculation

Impaired blood flow and oxygenation contribute to many ocular pathologies, including glaucoma. Here, a mathematical model is presented that combines an image-based heterogeneous representation of retinal arterioles with a compartmental description of capillaries and venules. The arteriolar model of the human retina is extrapolated from a previous mouse model based on confocal microscopy images. Every terminal arteriole is connected in series to compartments for capillaries and venules, yielding a hybrid model for predicting blood flow and oxygenation throughout the retinal microcirculation. A metabolic wall signal is calculated in each vessel according to blood and tissue oxygen levels. As expected, a higher average metabolic signal is generated in pathways with a lower average oxygen level. The model also predicts a wide range of metabolic signals dependent on oxygen levels and specific network location. For example, for high oxygen demand, a threefold range in metabolic signal is predicted despite nearly identical PO2 levels. This whole-network approach, including a spatially nonuniform structure, is needed to describe the metabolic status of the retina. This model provides the geometric and hemodynamic framework necessary to predict ocular blood flow regulation and will ultimately facilitate early detection and treatment of ischemic and metabolic disorders of the eye.

Impact of Type 1 Diabetes and Its Duration on Wall-to-lumen Ratio and Blood Flow in Retinal Arterioles

Background Subclinical damage to both the small and large vessels may contribute to the development and progression of cardiovascular disease. Scanning laser Doppler flowmetry (SLDF), an established method used to measure retinal microcirculation, has been successfully applied in hypertensive and post-stroke patients. To the best of our knowledge, no previous studies have assessed the impact of type 1 diabetes and its duration on retinal arteriole structure denoted by wall-to-lumen ratio (WLR) and retinal capillary flow (RCF). MethodsRetinal microcirculation was assessed in 158 patients with type 1 diabetes and 38 age-matched healthy controls. The diabetics were divided into 3 groups: group A with diabetes duration <12 months, group B with diabetes duration between 1 and 10 years, and group C >10 years of diabetes. Retinal capillary structure and perfusion were evaluated using a Heidelberg retina flowmeter and automatically analyzed with full-field perfusion imaging. Diabetes control was assessed by HbA1c measurement. ResultsBoth age and BMI were comparable in all the diabetic patients and the controls (mean age 24.8 ± 4.7 years, mean BMI 22.9 ± 4.1). The patients with newly diagnosed diabetes had the highest HbA1c (11.1%) whereas groups B and C were comparable in this respect (7.8% ± 1.9%; 8.0% ± 1.7%, respectively). In the univariate analyses, RCF was significantly higher in group A (297 ± 121 arbitrary units [AU]) vs group B (236 ± 52 AU; p = 0.007) and group C (236 ± 70 AU; p = 0.008) and comparable to that of the controls (p = 0.46). Additionally, the WLR was highest in group C compared to the other diabetic subgroups and controls (p = 0.47). ConclusionsNew-onset diabetes is associated with an increase in RCF, which then gradually decreased with the duration of the disease. Structural changes of the retinal arterioles estimated via WLR are evident later in the course of diabetes, especially when the disease duration exceeded 10 years. These results could not be explained by age or diabetes control. Our findings may have important implications for the understanding of the mechanisms underlying increased cardiovascular risk in type 1 diabetes.

Improved Retinal Microcirculation After Cardiac Surgery in Patients With Congenital Heart Disease

Background: Microcirculatory changes in congenital heart disease (CHD) patients undergoing cardiac surgery are not fully understood. We aimed to investigate the changes of retinal microcirculation in CHD patients after cardiac surgery by optical coherence tomography angiography (OCTA) and explore the association between retinal microcirculation and surgical outcome.Methods: This prospective observational study consisted of 71 CHD patients aged ≥6 years undergoing cardiac surgery including 19 cyanotic CHD (CCHD) and 52 acyanotic CHD (ACHD). Optical coherence tomography angiography (OCTA) was used to measure vessel density (VD) and capillary density (CD) of radial peripapillary capillary (RPC) and peripapillary, VD of superficial capillary plexus (SCP) and deep capillary plexus (DCP), thickness of retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC) preoperatively and 1 month postoperatively. Transthoracic echocardiography was conducted to measure macrocirculation.Results: In CCHD patients, VD and CD of RPC and peripapillary increased postoperatively (all P &lt; 0.05). In ACHD patients, VD of peripapillary, CD of RPC and peripapillary, and RNFL thickness increased postoperatively (all P &lt; 0.05). VD of SCP and DCP, and GCC thickness did not change significantly in CHD patients after surgery. Lower preoperative retinal microvascular density was associated with longer cardiopulmonary bypass (CPB) time and postoperative length of stay (PLOS). No correlation was found between microcirculatory and macrohemodynamic parameters (all P &gt; 0.05).Conclusions: Improved retinal microcirculation was observed after congenital cardiac surgery and impaired preoperative retinal microvasculature was associated with prolonged CPB time and PLOS, which might provide potential information about the outcome of congenital cardiac surgery.

OCT retinal angiography features in patients with rheumatoid arthritis: A pilot study

Purpose: To evaluate the superficial (SCP) and deep retinal capillary plexus (DCP) by mean of optical coherence tomography angiography (OCTA) in treatment-naïve patients affected by rheumatoid arthritis (RA). Methods: Between March 2019 and January 2020, patients with recent diagnosis of “definite RA” based on 2010 Rheumatoid Arthritis Classification Criteria were included in a Prospective, observational single center case-control study carried out at G.B. Bietti Foundation. Data were compared with those of 16 healthy age- and sex-matched subjects. Values of the vessel density (VD) of SCP and DCP, central foveal thickness (CFT), foveal avascular zone (FAZ) were collected by mean of OCTA. Main outcome measure was the VD alteration of SCP and DCP in treatment-naïve RA-patients. Results: No difference in age, sex-distribution, best-corrected visual acuity, CFT was registered between the two groups. OCTA data analysis showed in RA-patients a statistically significant reduction in the VD in the mean global area, inner ring, especially in the superior quadrant of the SCP. A trend of VD reduction was also registered in temporal, nasal, and inferior quadrants, respectively, although it did not reach a statistically significant value. Assessment of VD of DCP and FAZ area did not evidence any difference among the groups. Conclusions: OCTA allows to highlight the vascular remodeling of the retinal microcirculation in RA-patients, even in early stages of the disease, demonstrating a reduction of VD. Outcomes of the current investigation can provide new insight in the pathogenetic mechanism of RA and extend the potential applications of this diagnostic tool.

Retinal Microcirculation as a Correlate of a Systemic Capillary Impairment After Severe Acute Respiratory Syndrome Coronavirus 2 Infection

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), affects the pulmonary systems via angiotensin-converting enzyme-2 (ACE-2) receptor, being an entry to systemic infection. As COVID-19 disease features ACE-2 deficiency, a link to microcirculation is proposed. Optical coherence tomography angiography (OCT-A) enables non-invasive analysis of retinal microvasculature. Thus, an impaired systemic microcirculation might be mapped on retinal capillary system. As recent OCT-A studies, analyzing microcirculation in two subdivided layers, yielded contrary results, an increased subdivision of retinal microvasculature might offer an even more fine analysis. The aim of the study was to investigate retinal microcirculation by OCT-A after COVID-19 infection in three subdivided layers (I). In addition, short-term retinal affections were monitored during COVID-19 disease (II). Considering (I), a prospective study (33 patientspost−COVID and 28 controls) was done. Macula and peripapillary vessel density (VD) were scanned with the Spectralis II. Macula VD was measured in three layers: superficial vascular plexus (SVP), intermediate capillary plexus (ICP), and deep capillary plexus (DCP). Analysis was done by the EA-Tool, including an Anatomical Positioning System and an analysis of peripapillary VD by implementing Bruch's membrane opening (BMO) landmarks. Overall, circular (c1, c2, and c3) and sectorial VD (s1-s12) was analyzed. Considering (II), in a retrospective study, 29 patients with severe complications of COVID-19 infection, hospitalized at the intensive care unit, were monitored for retinal findings at bedside during hospitalization. (I) Overall (p = 0.0133) and circular (c1, p = 0.00257; c2, p = 0.0067; and c3, p = 0.0345). VD of the ICP was significantly reduced between patientspost−COVID and controls, respectively. Overall (p = 0.0179) and circular (c1, p = 0.0189) peripapillary VD was significantly reduced between both groups. Subgroup analysis of hospitalized vs. non-hospitalized patientspost−COVID yielded a significantly reduced VD of adjacent layers (DCP and SVP) with increased severity of COVID-19 disease. Clinical severity parameters showed a negative correlation with VD (ICP) and peripapillary VD. (II) Funduscopy yielded retinal hemorrhages and cotton wool spots in 17% of patients during SARS-CoV-2 infection. As VD of the ICP and peripapillary regions was significantly reduced after COVID-19 disease and showed a link to clinical severity markers, we assume that the severity of capillary impairment after COVID-19 infection is mapped on retinal microcirculation, visualized by non-invasive OCT-A.

POS0807 RETINAL VESSEL CALIBERS AS A NON-INVASIVE BIOMARKER OF INFLAMMATORY BURDEN IN PRIMARY SYSTEMIC VASCULITIS

Background:Primary Systemic Vasculitides (PSV) constitute a heterogeneous group of rare and potentially life-threatening autoimmune diseases, characterized by a varying degree of inflammatory response, leading to local or generalized vascular disease. Vessel involvement accounts for the micro- and macrovascular complications of the disease, along with the classic risk factors including, among others age and chronic use of steroids (1). Early identification of high-risk patients for cardiovascular disease (CVD) development and the contribution of inflammation towards this adverse outcome are still unmet needs. Alterations of retinal microcirculation have been independently associated with increased CVD risk in the general population (2). The potential changes of retinal vasculature and their association with disease activity and the magnitude of inflammation have not been studied in PSV so far.Objectives:To explore the effect of disease activity and inflammation on retinal microcirculation in PSV, classified according to vessel size as large, medium or small vessel vasculitides (LVV, MVV or SVV respectively), and polymyalgia rheumatica (PMR) without vasculitis.Methods:Fifty-nine patients, 43 with active disease [30 active vasculitis (12 LVV, 4 MVV, 14 SVV) and 13 PMR] and 16 with chronic inactive disease (13 vasculitis, 3 PMR) were studied. All patients were matched at 1:1 ratio with 59 controls, without underlying autoimmune/autoinflammatory disorder, neoplasia or infection, according to age, gender, CVD history, BMI, smoking, arterial hypertension, dyslipidemia, diabetes mellitus and treatment related to comorbidities. A total of 32 rheumatoid arthritis (RA) patients with mild to moderate inflammatory component as defined by standard of care acute phase reactants (ESR and CRP) and 16 chronic RA patients with normal ESR and CRP levels, matched 1:1 according to all the above parameters with 32 active and 16 inactive vasculitis/PMR patients respectively, served as disease controls. Digital retinal images were obtained and retinal vessel calibers were measured with a validated software to determine central retinal arteriolar and venular equivalents ratio (CRAE and CRVE respectively). For 16 patients with active vasculitis/PMR, retinal examination was performed in two time points (baseline and ≤ 6 months later).Results:In the overall population, patients with active Vasculitis/PMR had increased CRVE (213.8±21.7 vs 201.3±17.1, p<0.001) and CRAE (180.0±19.2 vs 164.1±17.5 p<0.001) compared to healthy controls. Separating patients according to disease type, we found that in LVV, MVV and PMR, CRAE (p≤0.05) and CRVE (p<0.05) were increased compared to control group, while in SVV only CRAE was increased (p<0.001). Interestingly, chronic patients with disease in remission displayed higher CRAE compared to matched controls (179.8±17.2 vs 169.1±11.1, p=0.006). After immunosuppressive treatment for ≤ 6 months CRVE and to a lesser extent CRAE were reduced (p=0.048 and 0.149 respectively) with a stronger statistical significance found in the Vasculitis group (p=0.026 and 0.069 respectively). Pearson’s linear correlation coefficient in active disease state (at baseline examination) revealed positive bivariate correlation only between CRVE with ESR and CRP. Patients with Vasculitis/PMR had also increased CRAE when compared to RA patients in both active and inactive disease status (182.8±19.4 vs 170.1±18.4, p<0.001 and 179.8±17.2 vs 166.3±17.9, p=0.005 respectively).Conclusion:Systemic inflammation alters retinal microcirculation in both a reversible (venules) and irreversible (arterioles) way, independently of PSV form. Thus, common disease specific pathogenetic mechanisms related to inflammation may be implicated in vascular remodeling. Sequential follow-up of PSV patients will address whether retinal vessel calibers may serve as a biomarker of disease activity and CVD development.References:[1]Argyropoulou OD et al. Curr Opin Rheumatol 2017.[2]Shaohua G et al. Current Atherosclerosis reports 2020.Disclosure of Interests:None declared