A normative blood velocity model in the exchange microvessels for discriminating health from disease: Healthy controls versus COVID-19 cases.

A usual practice in medicine is to search for "biomarkers" which are measurable quantities of a normal or abnormal biological process. Biomarkers can be biochemical or physical quantities of the body and although commonly used statistically in clinical settings, it is not usual for them to be connected to basic physiological models or equations. In this work, a normative blood velocity model framework for the exchange microvessels was introduced, combining the velocity-diffusion (V-J) equation and statistics, in order to define the normative range (NR) and normative area (NA) diagrams for discriminating normal (normemic) from abnormal (hyperemic or underemic) states, taking into account the microvessel diameter D. This is different from the usual statistical processing since there is a basis on the well-known physiological principle of the flow diffusion equation. The discriminative power of the average axial velocity model was successfully tested using a group of healthy individuals (Control Group) and a group of post COVID-19 patients (COVID-19 Group).

Breathlessness and exercise with virtual reality system in long-post-coronavirus disease 2019 patients

Long-post-coronavirus disease-2019 (COVID-19) patients tend to claim residual symptomatology from various systems, most importantly the respiratory and central nervous systems. Breathlessness and brain fog are the main complaints. The pulmonary function pattern is consistent with restrictive defects, which, in most cases, are self-resolved, while the cognitive profile may be impaired. Rehabilitation is an ongoing field for holistic management of long-post-COVID-19 patients. Virtual reality (VR) applications may represent an innovative implementation of rehabilitation. We aimed to investigate the effect of exercise with and without the VR system and to assess further breathlessness and functional fitness indicators in long-post-COVID-19 patients with mild cognitive impairment after self-selected exercise duration using the VR system. Twenty long-post-COVID-19 patients were enrolled in our study (age: 53.9 ± 9.1 years, male: 80%, body mass index: 28.1 ± 3.1 kg/m2). Participants' anthropometric data were recorded, and they underwent pulmonary functional test evaluation as well as sleep quality and cognitive assessment. The participants randomly exercised with and without a VR system (VR vs. no-VR) and, later, self-selected the exercise duration using the VR system. The results showed that exercise with VR resulted in a lower dyspnea score than exercise without VR. In conclusion, VR applications seem to be an attractive and safe tool for implementing rehabilitation. They can enhance performance during exercise and benefit patients with both respiratory and cognitive symptoms.

Breathlessness and exercise with virtual reality system in long-post-coronavirus disease 2019 patients.

Long-post-coronavirus disease-2019 (COVID-19) patients tend to claim residual symptomatology from various systems, most importantly the respiratory and central nervous systems. Breathlessness and brain fog are the main complaints. The pulmonary function pattern is consistent with restrictive defects, which, in most cases, are self-resolved, while the cognitive profile may be impaired. Rehabilitation is an ongoing field for holistic management of long-post-COVID-19 patients. Virtual reality (VR) applications may represent an innovative implementation of rehabilitation. We aimed to investigate the effect of exercise with and without the VR system and to assess further breathlessness and functional fitness indicators in long-post-COVID-19 patients with mild cognitive impairment after self-selected exercise duration using the VR system. Twenty long-post-COVID-19 patients were enrolled in our study (age: 53.9 ± 9.1 years, male: 80%, body mass index: 28.1 ± 3.1 kg/m2). Participants' anthropometric data were recorded, and they underwent pulmonary functional test evaluation as well as sleep quality and cognitive assessment. The participants randomly exercised with and without a VR system (VR vs. no-VR) and, later, self-selected the exercise duration using the VR system. The results showed that exercise with VR resulted in a lower dyspnea score than exercise without VR. In conclusion, VR applications seem to be an attractive and safe tool for implementing rehabilitation. They can enhance performance during exercise and benefit patients with both respiratory and cognitive symptoms.

Cognitive impairment in COVID‐19 Survivors: Analysis and Extensions on Population Studies in Greece

Background The aim of our study was to investigate the prevalence and associations of cognitive impairment in COVID‐19 survivors in the post‐acute setting. Method Our study is conducted in three post‐COVID‐19 outpatient clinics in tertiary hospitals in Greece. Eligible subjects included previously hospitalized COVID‐19 survivors with mild to moderate disease, returning for follow‐up at least two months post‐discharge. Exclusion criteria included intensive care unit admission, intubation, a history of neurodegenerative disease and other significant comorbidities. Study measurements included demographics, clinical evaluation, medical, family history, anthropometrics, 6‐minute walk test (6MWT), 30 seconds sit‐to‐stand (30STS), handgrip strength, spirometry, Pittsburgh Sleep Quality Index (PSQI), the Montreal Cognitive Assessment (MoCA), reactive oxygen metabolites (dROMs) and plasma antioxidant capacity (PAT). Cognitive impairment was considered on MoCA ≤24. Result 142 COVID‐19 survivors were included in the study (110 Male, 32 Female;Mean age of 56.16±10.92). A total of 47.2% presented with cognitive decline (CD) as indicated by a MoCA score ≤24. Cognitive decline prevalence by SARS‐CoV‐2 variant of concern (VOC) was 39.5%, 50% and 62.5% for Alpha, Beta and Delta, correspondingly. A binary logistic regression model controlling for age, gender and VOC indicated that the diffusing capacity for carbon monoxide (DLCO) was independently associated with MoCA ≤24 (p = 0.014, OR = 0.669, 95%CI: 0.484‐0.923). Compared to severe untreated OSAS (n = 28), distinct domains but similar prevalence of cognitive impairment was noted. Conclusion Diffusion capacity abnormalities for carbon monoxide in COVID‐19 survivors as noted in other studies, may be implicated in the development of cognitive impairment.

COVID-19 Severity and Mortality after Vaccination against SARS-CoV-2 in Central Greece.

BACKGROUND: Vaccination against SARS-CoV-2 (COVID-19) has become crucial for limiting disease transmission and reducing its severity, hospitalizations and mortality; however, despite universal acceptance, vaccine hesitancy is still significant. In the present manuscript, we aim to assess COVID-19-attributed mortality after the prevalence of new variants of the virus (Delta and Omicron viral strains) and to evaluate the vaccination effect. METHODS: All patients that were hospitalized due to COVID-19 infection in the Respiratory Department of a tertiary referral center in central Greece between 1st of June 2021 and 1st of February 2022 were included in the present study. RESULTS: 760 consecutive patients were included in the study; 89 (11.7%) were diagnosed with severe COVID-19 and 220 (38.7%) patients were fully vaccinated. In logistic regression, increased age (aOR = 1.12, p < 0.001), male gender (aOR = 2.29, p = 0.013) and vaccination against SARS-CoV-2 virus (aOR = 0.2, p < 0.001) were associated with mortality attributed to COVID-19 with a statistically significant association. Moreover, increased age (aOR = 1.09, p < 0.001), male gender (aOR = 1.92, p = 0.025) and vaccination against SARS-CoV-2 virus (aOR = 0.25, p < 0.001) were statistically significantly associated with clinical severity of COVID-19 infection. However, when comparing the length of hospitalization between vaccinated and unvaccinated patients, the difference was not statistically significant between the two groups (p = 0.138). CONCLUSIONS: Vaccination against SARS-CoV-2 virus had a protective effect in terms of mortality and clinical severity of COVID-19 during the fourth wave of the pandemic in Central Greece. The national vaccination policy has to focus on vulnerable populations that are expected to benefit the most from the vaccine's protection.

Post-COVID-19 Parkinsonism and Parkinson's Disease Pathogenesis: The Exosomal Cargo Hypothesis.

Parkinson's disease (PD) is the second most prevalent neurodegenerative disease after Alzheimer's disease, globally. Dopaminergic neuron degeneration in substantia nigra pars compacta and aggregation of misfolded alpha-synuclein are the PD hallmarks, accompanied by motor and non-motor symptoms. Several viruses have been linked to the appearance of a post-infection parkinsonian phenotype. Coronavirus disease 2019 (COVID-19), caused by emerging severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection, has evolved from a novel pneumonia to a multifaceted syndrome with multiple clinical manifestations, among which neurological sequalae appear insidious and potentially long-lasting. Exosomes are extracellular nanovesicles bearing a complex cargo of active biomolecules and playing crucial roles in intercellular communication under pathophysiological conditions. Exosomes constitute a reliable route for misfolded protein transmission, contributing to PD pathogenesis and diagnosis. Herein, we summarize recent evidence suggesting that SARS-CoV-2 infection shares numerous clinical manifestations and inflammatory and molecular pathways with PD. We carry on hypothesizing that these similarities may be reflected in exosomal cargo modulated by the virus in correlation with disease severity. Travelling from the periphery to the brain, SARS-CoV-2-related exosomal cargo contains SARS-CoV-2 RNA, viral proteins, inflammatory mediators, and modified host proteins that could operate as promoters of neurodegenerative and neuroinflammatory cascades, potentially leading to a future parkinsonism and PD development.

COVID-19 hemodynamic and thrombotic effect on the eye microcirculation after hospitalization: A quantitative case-control study.

BACKGROUND & OBJECTIVE: To quantify the hemodynamic and thrombotic effect of COVID-19 on the eye microcirculation of patients with thromboprophylaxis, shortly after hospital discharge. METHODS: This case-control study included 17 COVID-19 survivors (named "COVID-19 Group") and 17 healthy volunteers (named "Control Group"). Axial blood velocity (Vax) and percentage of occluded vessels (POV) were quantified by Conjunctival Video Capillaroscopy (CVC). Microvessels were identified and classified as "capillaries" (CAP), "postcapillary venules of size 1" (PC1), and "postcapillary venules of size 2" (PC2). RESULTS: The COVID-19 Group did not differ significantly in basic demographics from the Control Group. In the COVID-19 Group, there was a statistically significant (p <  0.001) reduction of Vax (39%, 49% and 47%, for CAP, PC1, and PC2, respectively) in comparison to the Control Group and a sizeable (p <  0.001) increase of POV (600%) in comparison to the Control Group. CONCLUSIONS: COVID-19 not only reduces significantly axial blood velocity in the capillaries and postcapillary venules of the eye but has also a devastating effect on microthrombosis (POV) despite thromboprophylaxis treatment. This gives a possible explanation for long COVID and a hint about the existence of a possibly unknown coagulation factor.

Perceived Symptoms, Mental Health and Quality of Life after Hospitalization in COVID-19 Patients.

Patients recovering from novel coronavirus are reporting a variety of symptoms such as cough, dyspnea, myalgia as well as psychological distress and poor quality of life. The aim of this study is to assess quality of life and psychological distress in COVID-19 survivors and the sociodemographic and clinical characteristics that affect COVID-19 survivors' mental health status and quality of life. A quantitative study was conducted among COVID-19 survivors, who had previously been admitted to the University Hospital of Larissa, Greece. Data were collected via a questionnaire consisting of three-parts. The first part consisted of questions about the demographic characteristics. The second part was the SF-36 QoL index. The third part was the Symptom Checklist-90r (SCL 90-R). In addition, clinical information such as the length and the department of hospitalization, days since discharge and pulmonary function (spirometry values) were recorded. From a total of 145 patients, 60% were male, aged 59.72 ± 12.74 and 78.6% of them were married; the majority had completed secondary education, 35.9% were pensioners and 58.6 were living in urban areas. The most frequently reported symptoms were fatigue (67.6%) and pain (44.8%) and 11.7% were experiencing psychological distress. Pain, loss of smell, mandatory education, ICU admission, female gender and the experiencing of skin disturbance are associated with poor physical QoL among COVID-19 recovered patients. Greek COVID-19 previously hospitalized patients were reporting several symptoms associated with COVID-19. Good QoL and mental health were also reported. Physical pain, loss of smell and female gender were associated with poor QoL and psychological distress.

Vulnerability of ß-Thalassemia Heterozygotes to COVID-19: Results from a Cohort Study.

Background: The assignment of mortality risk from SARS-CoV-2 virus (COVID-19) to vulnerable patient groups is an important step toward containment of the pandemic. Methods: A total of 760 patients with a positive molecular test for SARS-CoV-2 who were unvaccinated against COVID-19 were recruited between 1 January and 30 June 2021. Patients were grouped by age; sex; and common morbidities, such as atrial fibrillation, chronic respiratory disease, coronary disease, diabetes type II, neoplasia, hypertension and ß-Thalassemia heterozygosity. As a primary endpoint, we assessed mortality risk from COVID-19, and as secondary endpoints, we considered clinical severity and need for Intense Care Unit (ICU) admission. Results: In multivariate analysis, male sex (p < 0.001, OR = 2.59), increasing age (p < 0.001, OR = 1.049), ß-Thalassemia heterozygosity (p = 0.001, OR = 2.41) and chronic respiratory disease (p = 0.018, OR = 1.84) were identified as risk factors associated with mortality due to COVID-19. Moreover, male sex (p < 0.001, OR = 1.98), increasing age (p < 0.001, OR = 1.052) and ß-Thalassemia heterozygosity (p = 0.001, OR = 2.59) were associated with clinical severity in logistic regression. Regarding ICU admission, the risk factors were identified as male sex (p = 0.002, OR = 1.99), chronic respiratory disease (p = 0.007, OR = 2.06) and hypertension (p < 0.001, OR = 5.81). Conclusions: An increased mortality risk from COVID-19 was observed for older age, male sex, ß-Thalassemia heterozygosity and respiratory disease. Carriers of ß-Thalassemia were identified as more vulnerable for severe clinical symptomatology, but there was no increased possibility for ICU admission. Readjustment of these findings to consider impacts of variant strains prevailing during the latest viral outbreak among vulnerable patient groups may offer timely relief from the pandemic.

Physical Fitness Differences, Amenable to Hypoxia-Driven and Sarcopenia Pathophysiology, between Sleep Apnea and COVID-19.

Handgrip strength is an indirect indicator of physical fitness that is used in medical rehabilitation for its potential prognostic value. An increasing number of studies indicate that COVID-19 survivors experience impaired physical fitness for months following hospitalization. The aim of our study was to assess physical fitness indicator differences with another prevalent and hypoxia-driven disease, Obstructive Sleep Apnea Syndrome (OSAS). Our findings showed differences between post-COVID-19 and OSAS groups in cardiovascular responses, with post-COVID-19 patients exhibiting higher values for heart rate and in mean arterial blood pressure. Oxygen saturation (SpO2) was lower in post-COVID-19 patients during a six-minute walking test (6MWT), whereas the ΔSpO2 (the difference between the baseline to end of the 6MWT) was higher compared to OSAS patients. In patients of both groups, statistically significant correlations were detected between handgrip strength and distance during the 6MWT, anthropometric characteristics, and body composition parameters. In our study, COVID-19 survivors demonstrated a long-term reduction in muscle strength compared to OSAS patients. Lower handgrip strength has been independently associated with a prior COVID-19 hospitalization. The differences in muscle strength and oxygenation could be attributed to the abrupt onset of the disorder, which does not allow compensatory mechanisms to act effectively. Targeted rehabilitation focusing on such residual impairments may thus be indispensable within the setting of post-COVID-19 syndrome.

Investigating the prevalence of cognitive impairment in mild and moderate COVID-19 patients two months post-discharge: Associations with physical fitness and respiratory function

Background The aim of our study was to investigate the prevalence and associations of cognitive impairment in previously COVID-19 patients 2 months after discharge. Method Our study included previously hospitalized, consecutive COVID-19 patients with mild to moderate disease, followed up 2 months post discharge at a tertiary hospital?s outpatient clinic during May 2021. Exclusion criteria included intensive care unit admission, intubation, or a history of neurodegenerative disease and stroke prior to COVID-19. Prior to inclusion, eligible patients had provided written informed consent. The full battery of measurements in our study included demographics, medical and family history, anthropometrics, the 6-minute walk test (6MWT), the Borg Dyspnea Scale, spirometry, the Pittsburgh Sleep Quality Index (PSQI), the Epworth Sleepiness Scale (ESS), the Short Form 36 health Survey (SF-36), the Montreal Cognitive Assessment (MoCA) and the Symptom Checklist 90-R (SLC90-R), reactive oxygen metabolites (dROMs) and plasma antioxidant capacity (PAT test;FRAS5, Parma, Italy). Cognitive impairment was considered on a MoCA cutoff ≤24. Data are presented as mean ±SD or Frequencies (%). Correlations between continuous data were assessed via the Spearman?s Rho correlation coefficient, whereas associations were assessed via multiple linear regression (MLR) models. For all tests, a p-value <0.05 was considered statistically significant. Results A total of 32 subjects were included in the study (35 Male, 17 Female;Mean age of 61.6±9.4). A total of 56.2% presented with cognitive decline (CD) as indicated by a MoCA score <24. Principal component analysis revealed that short-term memory impairments and multidomain impairment without short-term memory deficits were the predominant patterns of cognitive impairment. MoCA score correlated with age (?=-0.513, p=0.003), waist circumference (?=-0.388, p=0.028) waist to hip ratio (?=-0.361, p=0.042) and SpO2 during 6MWT (1st, 4th and 6th minute;p<0.05). MLR indicated that after adjusting for age and gender, SpO2 at the 6th minute of the 6MWT was independently associated with MoCA score (Beta=0.579, p-value=0.001). Conclusion Our findings indicated that among 32 outpatient clinic subjects, 56.2% presented with cognitive decline. The associations with oxygen saturation and physical condition as detected by the 6MWT may indicate overlap with post-COVID-19 fatigue and warrants further investigation.

Eight Weeks Unsupervised Pulmonary Rehabilitation in Previously Hospitalized of SARS-CoV-2 Infection.

The aim of our study was to determine the impact of unsupervised Pulmonary Rehabilitation (uns-PR) on patients recovering from COVID-19, and determine its anthropometric, biological, demographic and fitness correlates. All patients (n = 20, age: 64.1 ± 9.9 years, 75% male) participated in unsupervised Pulmonary Rehabilitation program for eight weeks. We recorded anthropometric characteristics, pulmonary function parameters, while we performed 6 min walk test (6 MWT) and blood sampling for oxidative stress measurement before and after uns-PR. We observed differences before and after uns-PR during 6 MWT in hemodynamic parameters [systolic blood pressure in resting (138.7 ± 16.3 vs. 128.8 ± 8.6 mmHg, p = 0.005) and end of test (159.8 ± 13.5 vs. 152.0 ± 12.2 mmHg, p = 0.025), heart rate (5th min: 111.6 ± 16.9 vs. 105.4 ± 15.9 bpm, p = 0.049 and 6th min: 112.5 ± 18.3 vs. 106.9 ± 17.9 bpm, p = 0.039)], in oxygen saturation (4th min: 94.6 ± 2.9 vs. 95.8 ± 3.2%, p = 0.013 and 1st min of recovery: 97.8 ± 0.9 vs. 97.3 ± 0.9%), in dyspnea at the end of 6 MWT (1.3 ± 1.5 vs. 0.6 ± 0.9 score, p = 0.005), in distance (433.8 ± 102.2 vs. 519.2 ± 95.4 m, p < 0.001), in estimated O2 uptake (14.9 ± 2.4 vs. 16.9 ± 2.2 mL/min/kg, p < 0.001) in 30 s sit to stand (11.4 ± 3.2 vs. 14.1 ± 2.7 repetitions, p < 0.001)] Moreover, in plasma antioxidant capacity (2528.3 ± 303.2 vs. 2864.7 ± 574.8 U.cor., p = 0.027), in body composition parameters [body fat (32.2 ± 9.4 vs. 29.5 ± 8.2%, p = 0.003), visceral fat (14.0 ± 4.4 vs. 13.3 ± 4.2 score, p = 0.021), neck circumference (39.9 ± 3.4 vs. 37.8 ± 4.2 cm, p = 0.006) and muscle mass (30.1 ± 4.6 vs. 34.6 ± 7.4 kg, p = 0.030)] and sleep quality (6.7 ± 3.9 vs. 5.6 ± 3.3 score, p = 0.036) we observed differences before and after uns-PR. Our findings support the implementation of unsupervised pulmonary rehabilitation programs in patients following COVID-19 recovery, targeting the improvement of many aspects of long COVID-19 syndrome.