Clinical significance of assessing ADAMTS-13 and von Willebrand factor level in COVID-19 convalescent pregnant women.

Introduction. Coronavirus infection is associated with severe endotheliopathy, thromboinflammation and immunothrombosis leading to excessive release of von Willebrand factor (vWF) multimers from Weibel-Palade bodies, which can affect activity of ADAMTS-13 metalloproteinase (a disintegrin and metalloproteinase with thrombospondin type 1 motif, member 13) and the ADAMTS-13/vWF axis previously shown by us to be altered in non-pregnant women with severe COVID-19. Aim(s): to study a clinical role of hemostasis activation particularly ADAMTS-13/vWF axis in pregnant women after COVID-19. Materials and Methods. A prospective case-control study was conducted with pregnant women (n = 135) divided into 3 groups: group 1 included 45 women with prior COVID-19 during pregnancy, group 2 - 45 women in the acute phase of the infection during pregnancy, group 3 - 45 healthy pregnant women. The level of vWF and ADAMTS-13 was assessed in all patients. Results. The concentration of vWF antigen (vWF:Ag) in the acute period of the disease in pregnant women with COVID-19 was significantly higher compared to the control group (p < 0.001). ADAMTS-13 level in pregnant women after COVID-19 did not differ from that of in control group, while vWF level was significantly higher in 66.7 % (30/45). The ADAMTS-13/vWF ratio was increased and significantly differed both in pregnant patients during the acute period of the disease (p < 0.001) and pregnant women after infection (p = 0.0002) compared with the control group. Conclusion. Our results show that endotheliopathy was prominently manifested in pregnant women with COVID-19 and persisted for several months after disease. The ADAMTS-13/vWF ratio determines the pathway functioning, the risk of microcirculation disorders and clinical complications.Copyright © 2023 Vestnik Sankt-Peterburgskogo Universiteta, Yazyk i Literatura. All rights reserved.

Microvascular Alteration in COVID-19 Documented by Nailfold Capillaroscopy.

COVID-19 is a multisystemic disease that mainly affects and causes dysregulation of the endothelium, causing systemic manifestations. A nailfold video capillaroscopy is a safe, easy, and noninvasive method to evaluate microcirculation alteration. In this review, we analyzed the literature available to date regarding the object of nailfold video capillaroscopy (NVC) use in patients with a SARS-CoV-2 infection, both in the acute phase and after discharge. The scientific evidence pointed out the main alterations in capillary circulation shown by NVC, so reviewing the findings of each article allowed us to define and analyze the future prospects and needs for possibly including NVC within the management of patients with COVID-19, both during and after the acute phase.

Features of the tissue repair process in urgent surgical abdominal pathology in combination with covid-19

The OBJECTIVE was to study the process of wound healing after surgical interventions in patients with urgent surgical diseases in combination with a new coronavirus infection. METHODS AND MATERIALS. We observed for 80 patients with urgent abdominal diseases. Group I – 48 patients with various urgent diseases of the abdominal organs, group II – 32 patients with similar diseases occurring against the background of coronavirus infection. Stages of postoperative examination: 2, 4 and 7 days after surgery. The nature and rate of wound regeneration was assessed by cytological examination of wound exudate. In the tissues along the suture line, trophic indicators and microcirculation were recorded. RESULTS. The number of neutrophilic leukocytes in the wound exudate in group II exceeded the values of group I by 38.7–116.8 % with a slowed down dynamics of recovery. In the II group of patients, the number of tissue polyblasts was reduced at all stages of observation in comparison with the control group by 34.2–41.9 %. The number of lymphoid polyblasts in the main group was increased in comparison with the control group on days 2, 4, 7 of observation by 33.1 %, 63.2 %, 354.9 %, respectively. The indices of microcirculation in the tissues of the laparotomic wound in the group II of patients changed to a greater extent. The redox potential and oxygen diffusion coefficient in the group II were lower than the control figures by 9.8 – 37.2 % and 35.3 – 38.1 %, respectively. The number of complications according to the Clavien – Dindo classification in the group II of patients compared to the group I was more than 6 times higher. CONCLUSION. In patients with urgent diseases of the abdominal organs with concomitant coronavirus infection, the process of incomplete reparative tissue regeneration of the wound area slows down, which increases the risk of complications. The main factors that reduce the rate of tissue healing are disorders of microcirculation and bioenergetics. © 2022 Authors. All rights reserved.

The future of intensive care: the study of the microcirculation will help to guide our therapies.

The goal of hemodynamic resuscitation is to optimize the microcirculation of organs to meet their oxygen and metabolic needs. Clinicians are currently blind to what is happening in the microcirculation of organs, which prevents them from achieving an additional degree of individualization of the hemodynamic resuscitation at tissue level. Indeed, clinicians never know whether optimization of the microcirculation and tissue oxygenation is actually achieved after macrovascular hemodynamic optimization. The challenge for the future is to have noninvasive, easy-to-use equipment that allows reliable assessment and immediate quantitative analysis of the microcirculation at the bedside. There are different methods for assessing the microcirculation at the bedside; all have strengths and challenges. The use of automated analysis and the future possibility of introducing artificial intelligence into analysis software could eliminate observer bias and provide guidance on microvascular-targeted treatment options. In addition, to gain caregiver confidence and support for the need to monitor the microcirculation, it is necessary to demonstrate that incorporating microcirculation analysis into the reasoning guiding hemodynamic resuscitation prevents organ dysfunction and improves the outcome of critically ill patients.

Clinical significance of assessing ADAMTS-13 and von Willebrand factor level in COVID-19 convalescent pregnant women.

Introduction. Coronavirus infection is associated with severe endotheliopathy, thromboinflammation and immunothrombosis leading to excessive release of von Willebrand factor (vWF) multimers from Weibel-Palade bodies, which can affect activity of ADAMTS-13 metalloproteinase (a disintegrin and metalloproteinase with thrombospondin type 1 motif, member 13) and the ADAMTS-13/vWF axis previously shown by us to be altered in non-pregnant women with severe COVID-19. Aim(s): to study a clinical role of hemostasis activation particularly ADAMTS-13/vWF axis in pregnant women after COVID-19. Materials and Methods. A prospective case-control study was conducted with pregnant women (n = 135) divided into 3 groups: group 1 included 45 women with prior COVID-19 during pregnancy, group 2 - 45 women in the acute phase of the infection during pregnancy, group 3 - 45 healthy pregnant women. The level of vWF and ADAMTS-13 was assessed in all patients. Results. The concentration of vWF antigen (vWF:Ag) in the acute period of the disease in pregnant women with COVID-19 was significantly higher compared to the control group (p < 0.001). ADAMTS-13 level in pregnant women after COVID-19 did not differ from that of in control group, while vWF level was significantly higher in 66.7 % (30/45). The ADAMTS-13/vWF ratio was increased and significantly differed both in pregnant patients during the acute period of the disease (p < 0.001) and pregnant women after infection (p = 0.0002) compared with the control group. Conclusion. Our results show that endotheliopathy was prominently manifested in pregnant women with COVID-19 and persisted for several months after disease. The ADAMTS-13/vWF ratio determines the pathway functioning, the risk of microcirculation disorders and clinical complications.Copyright © 2023 Vestnik Sankt-Peterburgskogo Universiteta, Yazyk i Literatura. All rights reserved.

Altered tissue oxygenation in patients with post COVID-19 syndrome.

BACKGROUND: Post COVID-19 syndrome (PCS) is a complex condition with partly substantial impact on patients' social and professional life and overall life quality. Currently, the underlying cause(s) of PCS are unknown. Since PCS-specific symptoms could be associated with systemic alterations in tissue oxygen supply, we aimed to investigate changes in tissue oxygenation in patients with PCS. METHODS: A case-control study including 30 PCS patients (66.6 % males, 48.6 ± 11.2 years, mean time after (first) acute infection: 324 days), 16 cardiologic patients (CVD) (65.5 % males, 56.7 ± 6.3 years) and 11 young healthy controls (55 % males, 28.5 ± 7.4 years) was conducted. Near infrared spectroscopy (NIRS) was used to assess changes in tissue oxygenation during an arterial occlusion protocol on the non-dominant forearm (brachioradialis, 760/850 nm, 5 Hz). The protocol included 10-min rest, a 2-min baseline measurement followed by a 3-min ischemic period (upper-arm cuff, 50 mmHg above resting systolic blood pressure) and a 3-min reoxygenation period. PCS patients were grouped by presence of arterial hypertension and elevated BMI to assess the impact of risk factors. RESULTS: No differences in mean tissue oxygenation in the pre-occlusion phase existed between groups (p ≥ 0.566). During ischemia, comparisons of linear regressions slopes revealed slower oxygen desaturation for PCS patients (-0.064 %/s) compared to CVD patients (-0.08 %/s) and healthy subjects (-0.145 %/s) (p < 0.001). After cuff release, slowest speed for reoxygenation was detected in PCS patients at 0.84 %/s compared to CVD patients (1.04 %/s) and healthy controls (CG: 2.07 %/s) (p < 0.001). The differences between PCS patients and CVD patients during ischemia remained significant also after correction for risk factors. Analyses of complications during acute infection, persistence of PCS symptoms (time after acute infection), or PCS severity (number of lead symptoms) as confounding factors did not reveal a significant effect. CONCLUSIONS: This study provides evidence that the rate of tissue oxygen consumption is persistently altered in PCS and that PCS patients show an even slower decline in tissue oxygenation during occlusion than CVD patients. Our observations may at least partly explain PCS-specific symptoms such as physical impairment and fatigue.

Apropos of menstrual changes and abnormal uterine bleeding after COVID-19 vaccination.

It is news of 28 October 2022 that the Pharmacovigilance Risk Assessment Committee of the European Medicines Agency has recommended to add heavy menstrual bleeding among the side effects of unknown frequency inside the package insert of nucleoside-modified messenger ribonucleic acid vaccines to prevent coronavirus disease 2019 (COVID-19). The decision has been made in the light of the numerous reports of unexpected menstrual changes or abnormal uterine bleeding following COVID-19 vaccination. Here we advance a possible involvement of the particular adenohypophyseal microcirculation in these strange and still unexplained events.

Is arrhythmicity of microvascular "flowmotion" responsible for COVID-19-related acute respiratory distress syndrome and might it be treated through an adequate Mg supplementation?

Since the report of an emergence of severe respiratory viral infections of unknown etiology in China in December 2019, termed COVID-19-associated acute respiratory distress syndrome (ARDS), a large number of cases and deaths have been documented worldwide, with the pandemic still spreading around the world. In most critical cases, the acute symptoms may be accompanied by uncontrolled inflammatory cytokine responses and by multiorgan failure. The clinical observation that in severely ill patients, COVID-19 was characterized by cytokine storm and endothelial dysfunction, leading to fast and fatal progression of the disease, has prompted many investigators to consider COVID-19 as a systemic disease that primarily injures the vascular endothelium. Aim of this brief review is not to refute or even question a quite possible role of the vascular endothelial dysfunction as a potential trigger for ARDS, but rather to highlight a more probable role for the main function of the smooth muscle cells in the microcirculation, called "vasomotion", which helps physiologically to ensure an optimized energy supply to the tissues. Alterations in the rhythms of this microcirculatory vaso motion might thus play a similar role as a trigger of the ARDS diagnosed in COVID-19 patients. Furthermore, since obesity, type 2 diabetes, arterial hypertension, decrease in immune response, cytokine storm, endothelial dysfunction, and arrhythmias, which are frequent in COVID-19 patients, have been reported to be associated with hypomagnesemia, an adequate treatment with magnesium supplementation could be beneficial for COVID-19 patients in some specific cases and should also be taken into consideration.

Long COVID-19 syndrome: Association of cardiopulmonary impairment with a persistent platelet activation

Background: A considerable proportion of patients do not fully recover from COVID-19 infection and report symptoms that persist beyond the initial phase of infection: This condition is defined long-COVID-19 syndrome (LCS). LCS can involve lungs as well as several extrapulmonary organs, including the cardiovascular system. The risk and 1-year burden of cardiovascular diseases (CVD) is increased in COVID-19 survivors, even in subjects at low risk of CVD. Recently, we documented that acute COVID- 19 infection induces altered platelet activation state characterized by a prothrombotic phenotype and by the formation of platelet-leukocyte aggregates (PLA), that may be involved in the pulmonary microthrombi found in autoptic specimens. No data are yet available on the contribution of platelet activation to residual pulmonary impairment and procoagulant potential in LCS patients. Purpose(s): To study platelet activation status, microvesicle (MV) profile, platelet thrombin generation capacity (pTGC) in LCS patients enrolled at 6 months after resolution of the acute phase (6mo-FU), compared to acute COVID-19 infection patients. Method(s): 6mo-FU COVID-19 patients (n=24) with established LCS were enrolled at Centro Cardiologico Monzino. Residual pulmonary impairment was assessed by Cardiopulmonary Exercise Testing (CPET) and 64-rows- CT scan evaluation. Platelet activation (P-selectin, Tissue Factor [TF] and PLA) and MV profile were assessed by flow cytometry;pTGC by calibrated automated thrombogram. 46 patients enrolled during acute COVID-19 infection and 46 healthy subjects (HS) were used for comparison. Result(s): Dispnea in LCS patients was confirmed by CPET showing compromised alveolus-capillary membrane diffusion and residual pulmonary impairment. TF+-platelet and -MV levels were 3-fold (1.5% [1.2-2.9] vs 2.4% [1.6-5.7]) and 2-fold (217/mul [137-275] vs 435/mul [275-633]) lower at 6mo-FU compared to acute phase, being comparable to HS. pTGC behaved similarly. At 6mo-FU, the MV profile, in terms of total number and cell origin, returned to physiological levels. Conversely, although lower than that measured in acute phase, a 2.5-fold higher platelet P-selectin expression (6.9% [3-13.5] vs 11.7% [5.2-18.9]) and PLA formation (35.5% [27.4- 46.8] vs 67.7% [45.7-85.3]) was observed at 6mo-FU compared to HS. Interestingly, a significant correlation between PLA formation and residual pulmonary impairment was observed (r=-0.423;p=0.02). Conclusion(s): These data strengthen the hypothesis that the presence of PLA in the bloodstream, and thus also in the pulmonary microcirculation, may contribute to support pulmonary dysfunction still observed in LCS patients.

Impairment of Microcirculation and Endothelial Function in Children with Multisystem Inflammatory Syndrome (MIS-C)/Pediatric Inflammatory Multisystem Syndrome (PIMS): A Long-Term Study

Background: Multisystem inflammatory syndrome in children (MIS-C)/pediatric inflammatory multisystem syndrome(PIMS) is a rare but severe hyper inflammation following exposure to SARS-CoV-2. The exact pathogenesis is unknown, butSARS-CoV-2 is linked to vascular-endothelial pathology. We therefore longitudinally analyzed endothelial function and microcirculation in children with MIS-C/PIMS. Method(s): Overall 17 pediatric patients with MIS-C/PIMS (mean age: 9.4 +/- 4.5 years;30% female) were included in our study. They were examined during the acute phase and in follow-up visits after 3 and 6 months. We assessed the reactive hyperemia index (RHI) as a surrogate for the endothelial function using the Endo PAT device. The microcirculation was visualized using sublingual sidestream dark field (SDF) imaging, which permits analyzing the microvascular flow index (MFI)(0 = no flow, 1 = intermittent, 2 = sluggish, 3 = continuous). Result(s): During the acute phase of MIS-C/PIMS both, macrovascular and microvascular markers were distinctively restricted. Mean RHI was 1.11 +/- 0.25 indicating limited endothelial function in comparison to a group of healthy controls(mean RHI = 1.36 +/- 0.22;n = 14;mean age: 12.8 +/- 2.2 years;50% female). After 3 months, mean RHI improved to 1.42+/-0.45 and even increased to 1.75 +/- 0.66 after 6 months. SDF imaging revealed an impaired microcirculatory flow during the acute phase (mean MFI: 2.45 +/- 0.28), which surprisingly did not improve after three months (mean MFI: 2.45 +/- 0.33).Six months after the acute phase, the microvascular flow ameliorated toward a more continuous flow (mean MFI: 2.66 +/- 0.29). Conclusion(s): Our preliminary results indicate an impaired microcirculation and endothelial function in children with MIS-C/PIMS. The process of full vascular recovery seems to take several months. More research in this field is necessary to better understand the patho physiology and the time course of this rare new SARS-CoV-2-related syndrome.

The possibility of using perfluorocarbon compounds for virus-associated pneumonia treatment

The issues of practicality in using perfluorocarbon gas transport emulsions (or pure perfluorocarbons) in severe virus-associated pneumonia treatment were considered, including those caused by coronavirus infection. Perfluorocarbons are fully fluorinated carbon compounds, on the basis of which artificial blood substitutes have been developed - gas transport perfluorocarbon emulsions for medical purposes. Perfluorocarbon emulsions were widely used in the treatment of patients in critical conditions of various genesis at the end of the last-the beginning of this century, accompanied by hypoxia, disorders of rheological properties and microcirculation of blood, perfusion of organs and tissues, intoxication, and inflammation. Large-scale clinical trials have shown a domestic plasma substitute advantage based on perfluorocarbons (perfluoroan) over foreign analogues. It is quite obvious that the inclusion of perfluorocarbon emulsions in the treatment regimens of severe virus-associated pneumonia can significantly improve this category's treatment results after analyzing the accumulated experience. A potentially useful area of therapy for acute respiratory distress syndrome is partial fluid ventilation with the use of perfluorocarbons as respiratory fluids as shown in the result of many studies on animal models and existing clinical experience. There is no gas-liquid boundary in the alveoli, as a result of which, there is an improvement in gas exchange in the lungs and a decrease in pressure in the respiratory tract when using this technique, due to the unique physicochemical properties of liquid perfluorocarbons. A promising strategy for improving liquid ventilation effectiveness using perfluorocarbon compounds is a combination with other therapeutic methods, particularly with moderate hypothermia. Antibiotics, anesthetics, vasoactive substances, or exogenous surfactant can be delivered to the lungs during liquid ventilation with perfluorocarbons, including to the affected areas, which will enhance the drugs accumulation in the lung tissues and minimize their systemic effects. However, the indications and the optimal technique for conducting liquid ventilation of the lungs in patients with acute respiratory distress syndrome have not been determined currently. Further research is needed to clarify the indications, select devices, and determine the optimal dosage regimens for perfluorocarbons, as well as search for new technical solutions for this technique.

The respiratory exercise significance in the olfaction restoration in the postcovid period

One of the pathognomonic COVID19 signs, occurring in 8598% of patients, is olfactory dysfunction, developing in the absence of pronounced nflammation and edema of the nasal mucosa. A promising medicine direction that helps restore microcirculation, increase blood oxygenation, improve metabolism and regenerate olfactory epithelial cells is the Nadi Shodhana breathing exercise technique. Objective: To assess the possibilities of using the pranayama technique as a method of restorative olfactory treatment in the postcovid period. Materials and methods: 79 persons aged 22 to 68 years with olfactory disturbances occurring at COVID19 and persisting in the postcovid period were examined. As a restorative treatment for olfactory disorders, the patients of the main group were offered a course of Nadi Shodhana breathing xercises, which is an alternate nostril breathing. Breathing training consisted of three such cycles performed three times a day at the same time for 5 days. The possibility of using the pranayama technique was assessed according to the visual analog scale. The control group consisted of 74 patients with olfactory disorders after COVID19 comparable in sex and age with the main group. Results: Olfactory disorders are characteristic of postCOVID patients. Using Nadi Shodhana breathing exercise course can significantly reduce the lfactory dysfunction level in this patient category. It was showen that the pranayama technique is more effective in people under 40 years of age. It was lso established that the olfaction restoration largely depends on the duration of the dysfunction period. Conclusion: The study results make it possible to recommend the using breathing exercises in patients underwent COVID19 to restore olfaction n the postCOVID period. Copyright: © 2018 Zhao Qi et al.

Tracheotomy In Patients With Covid-19

Relevance. The coronavirus rush, which has appeared since December 2019, has an impact on economic, medical, and social development in all countries of the world. There are still no standard diagnostic and therapeutic plans aimed at limiting this infection. Purpose. To determine the therapeutic role of tracheostomy with patients with coronavirus infection. Material. The prospective study of 100 patients with coronavirus infection was carried out on the basis of State Budgetary Healthcare Institution "Interdistrict Multidisciplinary Hospital" in Nartkala city. When patients were admitted to the clinic, they were randomized into 2 groups depending on the therapy: the first group (comparison, n=50) - patients received traditional therapy in intensive care;the second (main, n=50) group - patients underwent tracheostomy in addition to standard therapy. The average age was 56.2+/-4.8 years. The women's average age was 55 years (55.0%), and the men's - 45 years (45.0%). Methods. Determination of the syndrome of endogenous intoxication, taxation of lipid peroxidation intensification. The local microcirculation was investigated by the apparatus LAKK-02. The activity of the coagulation-lytic blood system was found by thrombelastograph TEG 5000. Results. Early COVID-19 infection demonstrates signs of intoxication, oxidative depression, phospholipase activity, microcirculatory and hemostatic disorders. These changes were the cause of the development of life-threatening complications (neurological, pulmonary, cardiac, etc.). They were associated with the type of treatment. Traditional treatment and the use of mask oxygen turned out to be ineffective, since the homeostasis system disorders remained throughout the investigation period. The inclusion of tracheostomy in traditional therapy makes it possible to quickly improve the course of pathology as it purposefully affects the pathogenetic links of the homeostasis system. Conclusion. The use of tracheostomy in the scheme of standard treatment of coronavirus infection allows improving the effectiveness of general therapy of COVID-19 patients, especially with severe forms.Copyright © 2023, Codon Publications. All rights reserved.

Czech Cardiovascular Research and Innovation Day 2022

The proceedings contain 67 papers. The topics discussed include: role of endomyocardial biopsy in differential diagnosis of non- -ischemic cardiomyopathy;metformin treatment is associated with improved quality of life and outcome in patients with diabetes and advanced heart failure (HFREF);translational research in the field of inherited arrhythmias;same day discharge via a dedicated radial lounge - results of 1-year experience during the COVID-19 pandemic;functional assessment of microcirculation in takotsubo cardiomyopathy - a pilot study;an interplay of genetics and inflammation affecting left ventricular reverse remodeling in dilated cardiomyopathy;sildenafil inhibits pulmonary hypertension induced by left heart pressure overload in rats;predicting long-term survival after an ischemic stroke;and longitudinal trends in blood pressure, prevalence, awareness, treatment, and control of hypertension in the Czech population. are there any sex differences?.

FETAL GROWTH RETARDATION AS A COMPLICATION OF POST-COVID ENDOTHELIITIS: CAUSES, CONSEQUENCES, WAYS OF PREVENTION.

The risk of fetal intrauterine growth retardation (IUGR) is increased in women who have experienced acute infections, as well as in pregnant women with gynecological pathology and endocrine diseases. A woman's lack of nutrition also makes a negative contribution to the development of IUGR. The frequency of IUGR in the population is very variable and depends on a number of reasons. In practically healthy pregnant women, IUGR is registered in 3-5% of cases, in case of complicated obstetric and gynecological diagnosis and complicated pregnancy - in 10-25%. Morphofunctional disorders in the chorion/placenta in pregnant women with COVID-19 on the background of post-covid endotheliitis are the main pathogenetic factor in the development of preeclampsia, ectopic pregnancy, antenatal fetal death, and impaired condition of the fetus and newborns. Sufficient saturation of the pregnant woman's body with the nitric oxide donor L-arginine and L-carnitine (main cofactor of fatty acid metabolism in cells) with the improvement of microcirculation and the correction of hypovolemic disorders in the fetoplacental complex can be considered one of the real ways to prevent IUGR in women in the post-covid period. A review of the scientific literature on pathogenesis, diagnosis, impact on the life and health of a newborn with IUGR in women after COVID-19, as well as the possibilities of medical correction of placental dysfunction during pregnancy was performed. This analysis and our own clinical experience allow us to state the fact that after a coronavirus infection during pregnancy, one of the frequent and threatening for the further development of the child is the formation of placental dysfunction and IUGR. One of the ways to prevent these conditions is to saturate the woman's body with the nitric oxide donor L-arginine from the stage of pre-gravid preparation, which will provide the opportunity for adequate angiogenesis and development of the embryo/fetus. In the case of additional risk factors, such as coronavirus disease, complex therapy blood (Rheosorbilact), in combination with a nitric oxide donor and L-carnitine as an endothelium-protective agent (Tivor-L).Copyright © 2022 Authors. All rights reserved.

OCTA evaluation of posterior ocular blood flow in patients after COVID-19 infection without pneumonia.

INTRODUCTION: We aimed to demonstrate the changes in optic nerve and retinal microvascular structures with Optical Coherence Tomography Angiography (OCTA) in patients who had COVID-19 infection. METHODS: Prospective study. Retina, choroid and optic nerve head microvascular flow and vascular densities of both groups were measured by OCTA. RESULTS: OCTA measurements of 122 right eyes of a total of 122 patients, including 72 patients in the COVID-19 group and 50 patients in the control group, were included in the study. The Deep Capillary Plexus (DCP) Flow Area (FA) in the COVID-19 group was 1.42±0.23 mm2, in the control group was 1.50±0.15 mm2, Choriocapillary Plexus FA was 1.89±0.04 mm2 in the COVID-19 group, was 1.91±0.05 mm2 in the control group, and a statistically significant difference was found between the two groups (respectively; P=0.03; P=0.02). DCP Whole Vascular density (VD) values were 56.76±4.16% in the COVID-19 group, 58.28±3.88% in the control group; difference between the values was statistically significant (P=0.04). There was no statistically significant difference between the two groups in terms of optic nerve head flow areas and other parameters examined according to quadrants. CONCLUSIONS: Results show that the retinal microcirculation in subjects with mild disease is affected. Even if the disease is mild, patients may need to be followed up for retinal changes that may develop in the future.

Skin microcirculation reactivity to local thermal hyperaemia in patients with COVID-19 - A pilot observational study.

BACKGROUND: Endothelial dysfunction and microvascular disturbances are suggested to play a key role in higher morbidity and worse prognosis in patients with COVID-19 and cardiometabolic diseases. OBJECTIVE: Study was aimed to establish relationships between the skin microcirculation parameters and various clinical and laboratory indicators. METHODS: The study included 18 patients with moderate disease according to WHO criteria. Skin microcirculation measurements were performed by laser Doppler flowmetry using a heating test on the hairy skin of the right forearm. RESULTS: Baseline perfusion only correlated with C-reactive protein (Rs = 0.5, p = 0.034). Microcirculation indices characterising the development of hyperaemia during the first minute of heating (LTH1 and AUC60) showed significant correlations (Rs from 0.48 to 0.67, p <  0.05) with indices of general blood analysis and blood coagulation (fibrinogen, D-dimer, haemoglobin, erythrocyte count and haematocrit). Indexes characterising the dynamics of hyperaemia development over longer time intervals showed correlation with the glomerular filtration rate (Rs = 0.6, p = 0.009). CONCLUSION: Known COVID-19 risk factors (haemorheological parameters, age) are correlated with the microvascular reactivity to heating in patients with COVID 19. We suggest that, prospectively, the method of laser Doppler flowmetry could be used for non-invasive instrumental assessment of microcirculatory disorders in patients with COVID-19.

COVID-19 Detection Using Photoplethysmography and Neural Networks.

The early identification of microvascular changes in patients with Coronavirus Disease 2019 (COVID-19) may offer an important clinical opportunity. This study aimed to define a method, based on deep learning approaches, for the identification of COVID-19 patients from the analysis of the raw PPG signal, acquired with a pulse oximeter. To develop the method, we acquired the PPG signal of 93 COVID-19 patients and 90 healthy control subjects using a finger pulse oximeter. To select the good quality portions of the signal, we developed a template-matching method that excludes samples corrupted by noise or motion artefacts. These samples were subsequently used to develop a custom convolutional neural network model. The model accepts PPG signal segments as input and performs a binary classification between COVID-19 and control samples. The proposed model showed good performance in identifying COVID-19 patients, achieving 83.86% accuracy and 84.30% sensitivity (hold-out validation) on test data. The obtained results indicate that photoplethysmography may be a useful tool for microcirculation assessment and early recognition of SARS-CoV-2-induced microvascular changes. In addition, such a noninvasive and low-cost method is well suited for the development of a user-friendly system, potentially applicable even in resource-limited healthcare settings.

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Post-COVID Syndrome: A Common Neuroimmune Ground?

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating chronic disease of unknown etiology, sharing a similar clinical presentation with the increasingly recognized post-COVID syndrome. We performed the first cross-sectional study of ME/CFS in a community population in Russia. Then we described and compared some clinical and pathophysiological characteristics of ME/CFS and post-COVID syndrome as neuroimmune disorders. Of the cohort of 76 individuals who suggested themselves as suffering from ME/CFS, 56 were diagnosed with ME/CFS by clinicians according to ≥1 of the four most commonly used case definitions. Of the cohort of 14 individuals with post-COVID-19 syndrome, 14 met the diagnostic criteria for ME/CFS. The severity of anxiety/depressive symptoms did not correlate with the severity of fatigue either in ME/CFS or in post-COVID ME/CFS. Still, a positive correlation was found between the severity of fatigue and 20 other symptoms of ME/CFS related to the domains of "post-exertional exhaustion", "immune dysfunction", "sleep disturbances", "dysfunction of the autonomic nervous system", "neurological sensory/motor disorders" and "pain syndromes". Immunological abnormalities were identified in 12/12 patients with ME/CFS according to the results of laboratory testing. The prevalence of postural orthostatic tachycardia assessed in the active orthostatic test amounted to 37.5% in ME/CFS and 75.0% in post-COVID ME/CFS (the latter was higher than in healthy controls, p = 0.02). There was a more pronounced increase in heart rate starting from the 6th minute of the test in post-COVID ME/CFS compared with the control group. Assessment of the functional characteristics of microcirculation by laser doppler flowmetry revealed obvious and very similar changes in ME/CFS and post-COVID ME/CFS compared to the healthy controls. The identified laser doppler flowmetry pattern corresponded to the hyperemic form of microcirculation disorders usually observed in acute inflammatory response or in case of systemic vasoconstriction failure.