Endothelin-1 Plasma and Aqueous Humor Levels in Different Types of Glaucoma: A Systematic Review and Meta-Analysis.

Background and Objectives: Several studies suggest the complex relationship between Endothelin-1 (ET-1) levels with various types of glaucoma. This systematic review and meta-analysis explore ET-1 levels in plasma and aqueous humor among different types of glaucoma. Materials and Methods: A literature search (PubMed, ScienceDirect, Cochrane Library) was made up to April 2024 (PROSPERO: CRD42023430471). The results were synthesized according to PRISMA Guidelines. Results were presented as standardized mean differences (SMD) with 95% confidence intervals (CI). Results: A total of 2597 subjects (1513 patients with glaucoma vs. 1084 healthy controls) from 23 studies were included in a meta-analysis. Notably, patients with glaucoma reported significantly higher plasma levels of ET-1 compared to controls (SMD: 1.21, 95% CI: 0.59-1.82, p < 0.001). Particularly, plasma ET-1 levels were higher in primary open-angle glaucoma (POAG) (SMD: 0.87, 95% CI: 0.09-1.65, p < 0.05), normal-tension glaucoma (SMD: 0.86, 95% CI: 0.27-1.46, p = 0.05), and angle-closure glaucoma patients (SMD: 1.03, 95% CI: 0.43-1.63, p < 0.001) compared to healthy controls. Moreover, ET-1 aqueous humor levels were significantly higher in patients with glaucoma compared to controls (SMD: 1.60, 95% CI: 1.04-2.15, p < 0.001). In particular, aqueous humor levels were higher in POAG patients (SMD: 2.03 95% CI: 1.00-3.14, p < 0.001), and pseudoexfoliative glaucoma patients (SMD: 2.03, 95% CI: 1.00-3.07, p < 0.001) compared to controls. Conclusions: This meta-analysis indicates that elevated levels of ET-1 plasma and aqueous humor are significantly associated with different types of glaucoma. The pathogenesis of ET-1-related mechanisms may vary across different glaucoma types, indicating that possible therapeutic approaches targeting ET-1 pathways should be tailored to each specific glaucoma type.

Impaired left ventricular deformation and ventricular-arterial coupling in post-COVID-19: association with autonomic dysregulation.

Coronavirus disease-19 (COVID-19) has extended implications namely the long COVID-19 syndrome. We assessed over-time changes in left ventricular (LV) function, aortic stiffness, autonomic function, and ventricular-arterial coupling (VAC) in post-COVID-19 patients. We followed 34 post-COVID-19 subjects, up to 6 months post-hospital discharge. Subjects without COVID-19 served as control. We evaluated LV global longitudinal strain (LV-GLS), arterial stiffness [carotid-femoral pulse wave velocity (cf-PWV)], and heart rate variability -standard deviation of normal RR intervals (SDNN). VAC was estimated as the ratio of cf-PWV to LV-GLS. Post-COVID-19 individuals (1-month post-hospital discharge) presented with impaired LV-GLS [-18.4%(3.1) vs. -22.0%(2.7), P < 0.001], cf-PWV [12.1 m/s (3.2) vs. 9.6 m/s (1.9), P < 0.001], SDNN [111.3 ms (22.6) vs. 147.2 ms (14.0), P < 0.001], and VAC [-0.68 (0.22) vs. -0.44 (0.10), P < 0.001] compared to control. LV-GLS, SDNN, and VAC improved at the 6-month follow-up however they did not reach control levels. In post-COVID-19 subjects, SDNN and VAC were correlated at the 1-month (R = 0.499, P = 0.003) and 6-month (R = 0.372, P = 0.04) follow-up. Long COVID-19 syndrome was associated with impaired LV-GLS, SDNN, and VAC. Post-COVID-19 subjects presented with autonomic dysregulation associated with aortic stiffness, ventricular-arterial impairment, and LV dysfunction, even 6-months post-hospital discharge. These abnormalities may be related to the presence of long COVID-19 syndrome.

Molecular Mechanisms and Therapeutic Implications of Endothelial Dysfunction in Patients with Heart Failure.

Heart failure is a complex medical syndrome that is attributed to a number of risk factors; nevertheless, its clinical presentation is quite similar among the different etiologies. Heart failure displays a rapidly increasing prevalence due to the aging of the population and the success of medical treatment and devices. The pathophysiology of heart failure comprises several mechanisms, such as activation of neurohormonal systems, oxidative stress, dysfunctional calcium handling, impaired energy utilization, mitochondrial dysfunction, and inflammation, which are also implicated in the development of endothelial dysfunction. Heart failure with reduced ejection fraction is usually the result of myocardial loss, which progressively ends in myocardial remodeling. On the other hand, heart failure with preserved ejection fraction is common in patients with comorbidities such as diabetes mellitus, obesity, and hypertension, which trigger the creation of a micro-environment of chronic, ongoing inflammation. Interestingly, endothelial dysfunction of both peripheral vessels and coronary epicardial vessels and microcirculation is a common characteristic of both categories of heart failure and has been associated with worse cardiovascular outcomes. Indeed, exercise training and several heart failure drug categories display favorable effects against endothelial dysfunction apart from their established direct myocardial benefit.

Lipoprotein(a) in Atherosclerotic Diseases: From Pathophysiology to Diagnosis and Treatment.

Lipoprotein(a) (Lp(a)) is a low-density lipoprotein (LDL) cholesterol-like particle bound to apolipoprotein(a). Increased Lp(a) levels are an independent, heritable causal risk factor for atherosclerotic cardiovascular disease (ASCVD) as they are largely determined by variations in the Lp(a) gene (LPA) locus encoding apo(a). Lp(a) is the preferential lipoprotein carrier for oxidized phospholipids (OxPL), and its role adversely affects vascular inflammation, atherosclerotic lesions, endothelial function and thrombogenicity, which pathophysiologically leads to cardiovascular (CV) events. Despite this crucial role of Lp(a), its measurement lacks a globally unified method, and, between different laboratories, results need standardization. Standard antilipidemic therapies, such as statins, fibrates and ezetimibe, have a mediocre effect on Lp(a) levels, although it is not yet clear whether such treatments can affect CV events and prognosis. This narrative review aims to summarize knowledge regarding the mechanisms mediating the effect of Lp(a) on inflammation, atherosclerosis and thrombosis and discuss current diagnostic and therapeutic potentials.

The Impact of Cardiopulmonary Rehabilitation on Ventriculoarterial Coupling in Post-Coronavirus Disease-2019 Patients.

PURPOSE: Coronavirus disease-2019 (COVID-19) affects the cardiovascular system even after the acute phase of the disease. Cardiopulmonary rehabilitation may improve post-COVID-19 symptoms. This study aims to evaluate the impact of a cardiopulmonary rehabilitation program after acute COVID-19 on arterial stiffness, left ventricular function, and ventriculoarterial coupling (VAC). METHODS: Forty-eight adults were examined 1 (T0) and 3-mo (T1) following recovery from COVID-19 and randomized 1:1 to participate or not in a 3-mo rehabilitation program. Matched subjects were enrolled as a non-COVID-19 group. Arterial stiffness was evaluated by carotid-femoral pulse wave velocity (PWV). Left ventricular (LV) systolic performance was evaluated with global longitudinal strain (GLS). The PWV/LV-GLS ratio was calculated as an index of VAC. High-sensitivity C reactive protein (hs-CRP) was measured. RESULTS: At T0, convalescent patients with COVID-19 had impaired PWV ( P = .001) and reduced VAC ( P = .001) compared to non-COVID-19 subjects. PWV (8.15 ± 1.37 to 6.55 ± 0.98 m/sec, P < .001) and LV-GLS (-19.67 ± 1.98 to -21.3 ± 1.93%, P < .001) improved only in convalescent patients with COVID-19 undergoing rehabilitation. Similarly, VAC was only improved in the rehabilitation group (-0.42 ± 0.11 to -0.31 ± 0.06 m · sec -1  ·% -1 , P < .001). A significant improvement in VO 2max was noted after rehabilitation (15.70 [13.05, 21.45] to 18.30 [13.95, 23.75] ml · kg -1  · min -1 , P = .01). Finally, hs-CRP was improved in both groups with a significantly greater improvement in the rehabilitation group. CONCLUSION: A 3-mo rehabilitation program in convalesced patients with COVID-19 enhances the recovery of arterial stiffness, left ventricular function, and VAC, highlighting the beneficial mechanisms of rehabilitation in this patient population.

Retinal Microvascular Changes in Association with Endothelial Glycocalyx Damage and Arterial Stiffness in Patients with Diabetes Mellitus Type 2: A Cross-Sectional Study in a Greek Population.

PURPOSE: To evaluate the potential association between endothelial glycocalyx damage, as well as arterial stiffness, and the retinal changes on optical coherence tomography (OCT) and OCT-angiography (OCT-A) in patients with type 2 diabetes mellitus (DM). METHODS: Participants in this cross-sectional study were 65 patients with DM type 2 and 42 age- and gender-matched controls without DM. The demographic and clinical characteristics of the participants were recorded. All patients underwent a thorough ophthalmological examination and multimodal imaging, including fundus photography, OCT, and OCT-A. In addition, evaluation of the endothelial glycocalyx thickness by measuring the perfused boundary region (PBR5-25) of the sublingual microvessel, as well as of the arterial stiffness, by measuring the carotid-femoral pulse wave velocity (PWV), the central aortic pressures and the augmentation index (Aix) was performed. Univariate and multivariate logistic regression analysis was performed for the examination of the potential association between the eye imaging variables and the cardiovascular-related variables. The odds ratios (OR) with the respective 95% confidence intervals (CI) were calculated. A p-value < 0.05 was considered statistically significant. RESULTS: Patients with DM presented significantly higher PBR5-25 compared to controls without DM (p = 0.023). At the univariate analysis, increased PBR5-25 (≥2.19 µm vs. <2.19 µm) was associated with decreased peripapillary VD at the superior quadrant (univariate OR (95% CI) = 0.34 (0.12-0.93), p = 0.037). Multivariate logistic regression analysis showed that increased PWV (≥13.7 m/s vs. <13.7 m/s) was associated with an increased foveal avascular zone (FAZ) area on OCT-A (p = 0.044) and increased FAZ perimeter (p = 0.048). Moreover, increased Aix (≥14.745% vs. <14.745%) was associated with diabetic macular edema (DME) presence (p = 0.050) and increased perifoveal and parafoveal superior and temporal thickness on OCT (p < 0.05 for all associations). CONCLUSIONS: Markers of endothelial damage and arterial stiffness were associated with structural and microvascular retinal alterations in patients with DM, pointing out that OCT-A could be a useful biomarker for detecting potential cardiovascular risk in such patients.

Novel Approaches to the Management of Diabetes Mellitus in Patients with Coronary Artery Disease.

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in individuals with diabetes mellitus (DM). Although benefit has been attributed to the strict control of hyperglycemia with traditional antidiabetic treatments, novel antidiabetic medications have demonstrated cardiovascular (CV) safety and benefits by reducing major adverse cardiac events, improving heart failure (HF), and decreasing CVD-related mortality. Emerging data underline the interrelation between diabetes, as a metabolic disorder, and inflammation, endothelial dysfunction, and oxidative stress in the pathogenesis of microvascular and macrovascular complications. Conventional glucose-lowering medications demonstrate controversial CV effects. Dipeptidyl peptidase- 4 inhibitors have not only failed to prove to be beneficial in patients with coronary artery disease, but also their safety is questionable for the treatment of patients with CVD. However, metformin, as the first-line option for type 2 DM (T2DM), shows CVD protective properties for DM-induced atherosclerotic and macrovascular complications. Thiazolidinedione and sulfonylureas have questionable effects, as evidence from large studies shows a reduction in the risk of CV events and deaths, but with an increased rate of hospitalization for HF. Moreover, several studies have revealed that insulin monotherapy for T2DM treatment increases the risk of major CV events and deaths from HF, when compared to metformin, although it may reduce the risk of myocardial infarction. Finally, this review aimed to summarize the mechanisms of action of novel antidiabetic drugs acting as glucagon-like peptide-1 receptor agonists and sodium-glucose co-transporter-2 inhibitors that show favorable effects on blood pressure, lipid levels, and inflammation, leading to reduced CVD risk in T2DM patients.

Lipoprotein(a) and calcific aortic valve disease initiation and progression: a systematic review and meta-analysis.

Although evidence indicates the association of lipoprotein(a) [Lp(a)] with atherosclerosis, the link with calcific aortic valve disease (CAVD) is unclear. This systematic review and meta-analysis explores the connection between Lp(a) and aortic valve calcification and stenosis (AVS). We included all relevant studies, indexed in eight databases, up to February 2023. A total of 44 studies (163 139 subjects) were included, with 16 of them being further meta-analysed. Despite considerable heterogeneity, most studies support the relationship between Lp(a) and CAVD, especially in younger populations, with evidence of early aortic valve micro-calcification in elevated-Lp(a) populations. The quantitative synthesis showed higher Lp(a) levels, by 22.63 nmol/L (95% CI: 9.98-35.27), for patients with AVS, while meta-regressing the data revealed smaller Lp(a) differences for older populations with a higher proportion of females. The meta-analysis of eight studies providing genetic data, revealed that the minor alleles of both rs10455872 and rs3798220 LPA gene loci were associated with higher risk for AVS (pooled odds ratio 1.42; 95% CI: 1.34-1.50 and 1.27; 95% CI: 1.09-1.48, respectively). Importantly, high-Lp(a) individuals displayed not only faster AVS progression, by a mean difference of 0.09 m/s/year (95% CI: 0.09-0.09), but also a higher risk of serious adverse outcomes, including death (pooled hazard ratio 1.39; 95% CI: 1.01-1.90). These summary findings highlight the effect of Lp(a) on CAVD initiation, progression and outcomes, and support the early onset of Lp(a)-related subclinical lesions before clinical evidence.

The Role of Rehabilitation in Arterial Function Properties of Convalescent COVID-19 Patients.

Coronavirus disease (COVID-19) is a respiratory disease, although arterial function involvement has been documented. We assess the impact of a post-acute COVID-19 rehabilitation program on endothelium-dependent vasodilation and arterial wall properties. We enrolled 60 convalescent patients from COVID-19 and one-month post-acute disease, who were randomized at a 1:1 ratio in a 3-month cardiopulmonary rehabilitation program (study group) or not (control group). Endothelium-dependent vasodilation was evaluated by flow-mediated dilation (FMD), and arterial wall properties were evaluated by carotid-femoral pulse wave velocity (cf-PWV) and augmentation index (AIx) at 1 month and at 4 months post-acute disease. FMD was significantly improved in both the study (6.2 ± 1.8% vs. 8.6 ± 2.4%, p < 0.001) and control groups (5.9 ± 2.2% vs. 6.6 ± 1.8%, p = 0.009), but the improvement was significantly higher in the study group (rehabilitation) (p < 0.001). PWV was improved in the study group (8.2 ± 1.3 m/s vs. 6.6 ± 1.0 m/s, p < 0.001) but not in the control group (8.9 ± 1.8 m/s vs. 8.8 ± 1.9 m/s, p = 0.74). Similarly, AIx was improved in the study group (25.9 ± 9.8% vs. 21.1 ± 9.3%, p < 0.001) but not in the control group (27.6 ± 9.2% vs. 26.2 ± 9.8 m/s, p = 0.15). Convalescent COVID-19 subjects of the study group (rehabilitation) with increased serum levels of circulating IL-6 had a greater reduction in FMD. Conclusively, a 3-month cardiopulmonary post-acute COVID-19 rehabilitation program improves recovery of endothelium-dependent vasodilation and arteriosclerosis.

Lipoprotein (a) Levels and Abdominal Aortic Aneurysm. A Systematic Review and Meta-analysis.

BACKGROUND: Several studies have linked high Lipoprotein (a) (Lp(a)) concentrations to cardiovascular events, including the formation of Abdominal Aortic Aneurysms (AAA). We review and meta-analyze existing evidence on the association of Lp(a) levels with AAA. METHODS: Studies evaluating the link of Lp(a) with AAA, up to December 27th 2021, were identified by a systematic search of PubMed, SCOPUS, and Web of Science databases. The results were qualitatively and quantitatively synthesized according to PRISMA guidelines. Results are presented as standardized mean differences (SMD) with 95% confidence intervals (CI). RESULTS: A total of 5,078 subjects (1,637 patients with AAA vs. 3,441 controls) from 11 studies were included in the meta-analysis, with a mean age of 69.9 years and a male sex prevalence of 85.8%. Based on the qualitative synthesis, high Lp(a) concentrations are linked to abdominal aortic wall degradation and extracellular matrix disarrangement. Moreover, despite the considerable variability among races, high Lp(a) levels are related to increased AAA risk, independently of race differences. Accordingly, patients with AAA displayed significantly higher Lp(a) levels compared to controls (SMD: 0.86, 95% CI: 0.55-1.17, p < 0.001). The outcome was not affected in a sensitivity analysis excluding three outlying studies (SMD: 0.40, 95% CI: 0.22-0.58, p < 0.001). CONCLUSION: This meta-analysis indicates the association between high Lp(a) levels and the presence of AAA, although existing literature presents high heterogeneity. Further studies are needed to standardize Lp(a) measurements and to conclude whether Lp(a) can be used as a sensitive biomarker of early presymptomatic AAA diagnosis.

Vaccination Against SARS-CoV-2 Protects from COVID-19-induced Endothelial Dysfunction.

BACKGROUND: Coronavirus Disease-19 (COVID-19) is implicated in endotheliitis, which adversely affects cardiovascular events. The impact of vaccination with COVID-19 on the clinical outcome of patients is documented. OBJECTIVE: To evaluate the impact of vaccination with COVID-19 on the severe acute respiratory syndrome, coronavirus-2 (SARS-CoV-2) infection-related endothelial impairment. METHODS: We enrolled 45 patients hospitalized for COVID-19 (either vaccinated or not against SARS-CoV-2). Clinical and laboratory data were collected, and brachial artery flow-mediated dilation (FMD) was evaluated. Subjects without COVID-19 were used as the control group. RESULTS: There was no difference in age (64.7 ± 7.5 years vs. 61.2 ± 11.1 years vs. 62.4 ± 9.5, p = 0.28), male sex (49% vs. 60% vs. 52%, p = 0.71), control subjects, vaccinated, and unvaccinated subjects with COVID-19, respectively. Of the patients with COVID-19, 44% were vaccinated against SARS-CoV-2. Unvaccinated COVID-19 patients had significantly impaired FMD compared to vaccinated COVID-19 patients and Control subjects (2.05 ± 2.41 % vs. 7.24 ± 2.52% vs. 7.36 ± 2.94 %, p <0.001). Importantly, post hoc tests revealed that unvaccinated COVID-19 patients had significantly impaired FMD from both Vaccinated COVID-19 subjects (p <0.001) and from Control subjects (p <0.001). There was no difference in FMD between the control group and the vaccinated COVID-19 group (p = 0.99). CONCLUSION: Hospitalized patients with COVID-19 present endothelial dysfunction in the acute phase of the disease. Endothelial function in unvaccinated patients with COVID-19 is impaired compared to control subjects as well compared to vaccinated patients with COVID-19. Vaccinated hospitalized subjects with COVID-19 do not show endothelial dysfunction, strengthening the protective role of vaccination against SARS-CoV-2.

Current Concepts and Future Applications of Non-Invasive Functional and Anatomical Evaluation of Coronary Artery Disease.

Over the last decades, significant advances have been achieved in the treatment of coronary artery disease (CAD). Proper non-invasive diagnosis and appropriate management based on functional information and the extension of ischemia or viability remain the cornerstone in the fight against adverse CAD events. Stress echocardiography and single photon emission computed tomography are often used for the evaluation of ischemia. Advancements in non-invasive imaging modalities such as computed tomography (CT) coronary angiography and cardiac magnetic resonance imaging (MRI) have not only allowed non-invasive imaging of coronary artery lumen but also provide additional functional information. Other characteristics regarding the plaque morphology can be further evaluated with the latest modalities achieving a morpho-functional evaluation of CAD. Advances in the utilization of positron emission tomography (PET), as well as software advancements especially regarding cardiac CT, may provide additional prognostic information to a more evidence-based treatment decision. Since the armamentarium on non-invasive imaging modalities has evolved, the knowledge of the capabilities and limitations of each imaging modality should be evaluated in a case-by-case basis to achieve the best diagnosis and treatment decision. In this review article, we present the most recent advances in the noninvasive anatomical and functional evaluation of CAD.

Interleukin-1 in Coronary Artery Disease.

Cardiovascular disease is the leading cause of mortality worldwide. Inflammation has long been established as a key component in the pathophysiology of coronary artery disease. The interleukin-1 family consists of 11 members that regulate the inflammatory response through both pro- and anti-inflammatory properties with the Nod-like receptor (NLR) family pyrin domain containing 3 inflammasome having a pivotal role in the process of converting interleukin-1 beta and interleukin- 18, two key inflammatory mediators, into their mature forms. Interleukin-1 affects various cell types that participate in the pathogenesis of atherosclerosis as it enhances the expression of leukocyte adhesion molecules on the surface of endothelial cells and augments the permeability of the endothelial cell barrier, attracting monocytes and macrophages into the vessel wall and aids the migration of smooth muscle cells toward atheroma. It also enhances the aggregation of low-density lipoprotein particles in endothelium and smooth muscle cells and exhibits procoagulant activity by inducing synthesis, cell-surface expression and release of tissue factor in endothelial cells, promoting platelet adhesion. The value of interleukin-1 as a diagnostic biomarker is currently limited, but interleukin-1 beta, interleukin-18 and interleukin-37 have shown promising data regarding their prognostic value in coronary artery disease. Importantly, target anti-inflammatory treatments have shown promising results regarding atherosclerosis progression and cardiovascular events. In this review article, we focus on the immense role of interleukin-1 in atherosclerosis progression, inflammation cascade and in the clinical application of target anti-inflammatory treatments.

The Role of Endothelial Related Circulating Biomarkers in COVID-19. A Systematic Review and Meta-analysis.

BACKGROUND: Several studies have revealed the link between Coronavirus Disease 2019 (COVID-19) and endothelial dysfunction. To better understand the global pattern of this relationship, we conducted a meta-analysis on endothelial biomarkers related to COVID-19 severity. METHODS: We systematically searched the literature up to March 10, 2021, for studies investigating the association between COVID-19 severity and the following endothelial biomarkers: Intercellular Adhesion Molecule 1 (ICAM-1), Vascular Cell Adhesion Molecule 1 (VCAM-1), E-selectin, P-selectin, Von Willebrand Factor Antigen (VWFAg), soluble Thrombomodulin (sTM), Mid-regional pro-adrenomedullin (MR-proADM), and Angiopoietin-2 (Ang-2). Pooled estimates and mean differences (PMD) for each biomarker were reported. RESULTS: A total of 27 studies (n=2213 patients) were included. Critically ill patients presented with higher levels of MR-proADM (PMD: 0.71 nmol/L, 95% CI: 0.22 to 1.20 nmol/L, p=0.02), E-selectin (PMD: 13,32 pg/ml, 95% CI: 4,89 to 21,75 pg/ml, p=0.008), VCAM-1 (PMD: 479 ng/ml, 95% CI: 64 to 896 ng/ml, p=0.03), VWF-Ag (PMD: 110.5 IU/dl, 95% CI: 44.8 to 176.1 IU/dl, p=0.04) and Ang-2 (PMD: 2388 pg/ml, 95% CI: 1121 to 3655 pg/ml, p=0.003), as compared to non-critically ill ones. ICAM-1, P-selectin and thrombomodulin did not differ between the two groups (p>0.05). CONCLUSION: Endothelial biomarkers display significant heterogeneity in COVID-19 patients, with higher MR-proADM, E-selectin, VCAM-1, VWF-Ag, and Ang-2 levels being associated with increased severity. These findings strengthen the evidence on the key role of endothelial dysfunction in disease progress.

Endothelial dysfunction in acute and long standing COVID-19: A prospective cohort study.

BACKGROUND: Coronavirus disease-19 (COVID-19) is implicated by active endotheliitis, and cardiovascular morbidity. The long-COVID-19 syndrome implications in atherosclerosis have not been elucidated yet. We assessed the immediate, intermediate, and long-term effects of COVID-19 on endothelial function. METHODS: In this prospective cohort study, patients hospitalized for COVID-19 at the medical ward or Intensive Care Unit (ICU) were enrolled and followed up to 6 months post-hospital discharge. Medical history and laboratory examinations were performed while the endothelial function was assessed by brachial artery flow-mediated dilation (FMD). Comparison with propensity score-matched cohort (control group) was performed at the acute (upon hospital admission) and follow-up (1 and 6 months) stages. RESULTS: Seventy-three patients diagnosed with COVID-19 (37% admitted in ICU) were recruited. FMD was significantly (p < 0.001) impaired in the COVID-19 group (1.65 ± 2.31%) compared to the control (6.51 ± 2.91%). ICU-treated subjects presented significantly impaired (p = 0.001) FMD (0.48 ± 1.01%) compared to those treated in the medical ward (2.33 ± 2.57%). During hospitalization, FMD was inversely associated with Interleukin-6 and Troponin I (p < 0.05 for all). Although, a significant improvement in FMD was noted during the follow-up (acute: 1.75 ± 2.19% vs. 1 month: 4.23 ± 2.02%, vs. 6 months: 5.24 ± 1.62%; p = 0.001), FMD remained impaired compared to control (6.48 ± 3.08%) at 1 month (p < 0.001) and 6 months (p = 0.01) post-hospital discharge. CONCLUSION: COVID-19 patients develop a notable endothelial dysfunction, which is progressively improved over a 6-month follow-up but remains impaired compared to healthy controls subjects. Whether chronic dysregulation of endothelial function following COVID-19 could be accompanied by a residual risk for cardiovascular and thrombotic events merits further research.