Pulmonary Embolism and Increased Levels of d-Dimer in Patients with Coronavirus Disease

Postacute Sequelae of COVID (PASC or Long COVID): An Evidenced-Based Approach

While the acute manifestations of infectious diseases are well known, in some individuals, symptoms can either persist or appear after the acute period. Postviral fatigue syndromes are recognized with other viral infections and are described after coronavirus disease 2019 (COVID-19). We have a growing number of individuals with symptoms that persist for weeks, months, and years. Here, we share the evidence regarding the abnormalities associated with postacute sequelae of COVID-19 (PASC) and therapeutics. We describe physiological and biochemical abnormalities seen in individuals reporting PASC. We describe the several evidence-based interventions to offer patients. It is expected that this growing understanding of the mechanisms driving PASC and the benefits seen with certain therapeutics may not only lead to better outcomes for those with PASC but may also have the potential for understanding and treating other postinfectious sequelae.

Vascular dysfunction in hemorrhagic viral fevers: opportunities for organotypic modeling

The hemorrhagic fever viruses (HFVs) cause severe or fatal infections in humans. Named after their common symptom hemorrhage, these viruses induce significant vascular dysfunction by affecting endothelial cells, altering immunity, and disrupting the clotting system. Despite advances in treatments, such as cytokine blocking therapies, disease modifying treatment for this class of pathogen remains elusive. Improved understanding of the pathogenesis of these infections could provide new avenues to treatment. While animal models and traditional 2D cell cultures have contributed insight into the mechanisms by which these pathogens affect the vasculature, these models fall short in replicatingin vivohuman vascular dynamics. The emergence of microphysiological systems (MPSs) offers promising avenues for modeling these complex interactions. These MPS or 'organ-on-chip' models present opportunities to better mimic human vascular responses and thus aid in treatment development. In this review, we explore the impact of HFV on the vasculature by causing endothelial dysfunction, blood clotting irregularities, and immune dysregulation. We highlight how existing MPS have elucidated features of HFV pathogenesis as well as discuss existing knowledge gaps and the challenges in modeling these interactions using MPS. Understanding the intricate mechanisms of vascular dysfunction caused by HFV is crucial in developing therapies not only for these infections, but also for other vasculotropic conditions like sepsis.

Diagnostic value of coagulation index and serum inflammatory cytokines in hemorrhagic stroke patients with pulmonary infection in the sequelae stage

BACKGROUND

Stroke is the second reason for global deaths and a major reason for disabilities.

OBJECTIVE

To unravel the clinical value of the coagulation index and serum inflammatory cytokines in hemorrhagic stroke patients with pulmonary infection in the sequelae stage.

METHODS

Altogether, 130 hemorrhagic stroke patients who received treatment in Hebei General Hospital from April 2019 to December 2020 were selected. Patients were classified into the infection group (n= 65) and non-infection group (n= 65) according to whether they had a pulmonary infection in the sequelae stage of hemorrhagic stroke. Levels of coagulation index and serum inflammatory cytokines of patients in two groups were compared. Multiple linear regression analysis was used to analyze pulmonary infection-related factors of hemorrhagic stroke patients. The diagnostic value of the coagulation index and serum inflammatory cytokines in pulmonary infection was analyzed by the receiver operating characteristic (ROC) curve.

RESULTS

Prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (FIB), D-dimer (D-D), platelet (PLT) related to coagulation function levels and interleukin 1β (IL-1β), interleukin 17 (IL-17) related to serum inflammatory cytokines levels of patients in the infection group were higher than those in non-infection groups (p< 0.05). Multiple linear regression analysis uncovered that FIB, D-D, PLT, and IL-17 were influencing factors of pulmonary infection in the sequelae of patients with hemorrhagic stroke (p< 0.05). Area under the curve (AUC) values of pulmonary infection in the sequelae stage of patients with hemorrhagic stroke diagnosed by FIB, D-D, PLT, and IL-17 were 0.823, 0.758, 0.660, and 0.755, respectively.

CONCLUSION

FIB, D-D, PLT, and IL-17 levels could be used for pulmonary infection diagnosis in the sequelae stage of hemorrhagic stroke patients.

Immunothrombosis and Complement Activation Contribute to Disease Severity and Adverse Outcome in COVID-19

Severe COVID-19 is characterized by systemic inflammation and multiple organ dysfunction syndrome (MODS). Arterial and venous thrombosis are involved in the pathogenesis of MODS and fatality in COVID-19. There is evidence that complement and neutrophil activation in the form of neutrophil extracellular traps are main drivers for development of microvascular complications in COVID-19. Plasma and serum samples were collected from 83 patients infected by SARS-CoV-2 during the two first waves of COVID-19, before the availability of SARS-CoV-2 vaccination. Samples were collected at enrollment, day 11, and day 28; and patients had differing severity of disease. In this comprehensive study, we measured cell-free DNA, neutrophil activation, deoxyribonuclease I activity, complement activation, and D-dimers in longitudinal samples of COVID-19 patients. We show that all the above markers, except deoxyribonuclease I activity, increased with disease severity. Moreover, we provide evidence that in severe disease there is continued neutrophil and complement activation, as well as D-dimer formation and nucleosome release, whereas in mild and moderate disease all these markers decrease over time. These findings suggest that neutrophil and complement activation are important drivers of microvascular complications and that they reflect immunothrombosis in these patients. Neutrophil activation, complement activation, cell-free DNA, and D-dimer levels have the potential to serve as reliable biomarkers for disease severity and fatality in COVID-19. They might also serve as suitable markers with which to monitor the efficacy of therapeutic interventions in COVID-19.

Novel inflammatory markers in patients with severe COVID-19 and a pulmonary thrombotic event

Venous thromboembolism (VTE), clinically manifested as deep vein thrombosis (DVT) or acute pulmonary embolism (PE), is the third most common acute cardiovascular syndrome following myocardial infarction and stroke. The annual incidence of PE is between 39 and 115 per 100,000 inhabitants. The incidence of VTE is almost eight times higher in people aged 80 and older than in the fifth decade of life. We performed a retrospective study of 226 COVID-19 patients and selected group of patients who experienced a pulmonary thrombotic event. The incidence of PE in hospitalized COVID-19 patients was approximately 1.9-8.9%. The retrospective nature of the analyzed cohorts and relatively short observation periods could have led to underestimation of the actual incidence of PE. This study underlines the role of novel inflammatory biomarkers such as neutrophil to lymphocyte ratio and platelet to lymphocyte ratio in patients with a pulmonary thrombotic event in COVID-19. We suggest that these biomarkers may have high assessment value and complement routinely used biomarkers.

Development of a new prognostic index PNPI for prognosis prediction of CKD patients with pneumonia at hospital admission

Background

The aim of this study was to investigate the relationship between pneumonia and chronic kidney disease (CKD), to elucidate potential risk factors, and to develop a new predictive model for the poor prognosis of pneumonia in CKD patients.

Method

We conducted a retrospective observational study of CKD patients admitted to Tongji Hospital between June 2012 and June 2022. Demographic information, comorbidities or laboratory tests were collected. Applying univariate and multivariate logistic regression analyses, independent risk factors associated with a poor prognosis (i.e., respiratory failure, shock, combined other organ failure, and/or death during hospitalization) for pneumonia in CKD patients were discovered, with nomogram model subsequently developed. Predictive model was compared with other commonly used pneumonia severity scores.

Result

Of 3,193 CKD patients with pneumonia, 1,013 (31.7%) met the primary endpoint during hospitalization. Risk factors predicting poor prognosis of pneumonia in CKD patients were selected on the result of multivariate logistic regression models, including chronic cardiac disease; CKD stage; elevated neutrophil to lymphocyte ratio (NLR) and D-dimer; decreased platelets, PTA, and chloride iron; and significant symptom presence and GGO presentation on CT. The nomogram model outperformed other pneumonia severity indices with AUC of 0.82 (95% CI: 0.80, 0.84) in training set and 0.83 (95% CI: 0.80, 0.86) in testing set. In addition, calibration curve and decision curve analysis (DCA) proved its efficiency and adaptability.

Conclusion

We designed a clinical prediction model PNPI (pneumonia in nephropathy patients prognostic index) to assess the risk of poor prognosis in CKD patients with pneumonia, which may be generalized after more external validation.

Artificial intelligence and discrete-event simulation for capacity management of intensive care units during the Covid-19 pandemic: A case study

The Covid-19 pandemic has pushed the Intensive Care Units (ICUs) into significant operational disruptions. The rapid evolution of this disease, the bed capacity constraints, the wide variety of patient profiles, and the imbalances within health supply chains still represent a challenge for policymakers. This paper aims to use Artificial Intelligence (AI) and Discrete-Event Simulation (DES) to support ICU bed capacity management during Covid-19. The proposed approach was validated in a Spanish hospital chain where we initially identified the predictors of ICU admission in Covid-19 patients. Second, we applied Random Forest (RF) to predict ICU admission likelihood using patient data collected in the Emergency Department (ED). Finally, we included the RF outcomes in a DES model to assist decision-makers in evaluating new ICU bed configurations responding to the patient transfer expected from downstream services. The results evidenced that the median bed waiting time declined between 32.42 and 48.03 min after intervention.

Pathogenic mechanisms of post-acute sequelae of SARS-CoV-2 infection (PASC)

COVID-19, with persistent and new onset of symptoms such as fatigue, post-exertional malaise, and cognitive dysfunction that last for months and impact everyday functioning, is referred to as Long COVID under the general category of post-acute sequelae of SARS-CoV-2 infection (PASC). PASC is highly heterogenous and may be associated with multisystem tissue damage/dysfunction including acute encephalitis, cardiopulmonary syndromes, fibrosis, hepatobiliary damages, gastrointestinal dysregulation, myocardial infarction, neuromuscular syndromes, neuropsychiatric disorders, pulmonary damage, renal failure, stroke, and vascular endothelial dysregulation. A better understanding of the pathophysiologic mechanisms underlying PASC is essential to guide prevention and treatment. This review addresses potential mechanisms and hypotheses that connect SARS-CoV-2 infection to long-term health consequences. Comparisons between PASC and other virus-initiated chronic syndromes such as myalgic encephalomyelitis/chronic fatigue syndrome and postural orthostatic tachycardia syndrome will be addressed. Aligning symptoms with other chronic syndromes and identifying potentially regulated common underlining pathways may be necessary for understanding the true nature of PASC. The discussed contributors to PASC symptoms include sequelae from acute SARS-CoV-2 injury to one or more organs, persistent reservoirs of the replicating virus or its remnants in several tissues, re-activation of latent pathogens such as Epstein-Barr and herpes viruses in COVID-19 immune-dysregulated tissue environment, SARS-CoV-2 interactions with host microbiome/virome communities, clotting/coagulation dysregulation, dysfunctional brainstem/vagus nerve signaling, dysautonomia or autonomic dysfunction, ongoing activity of primed immune cells, and autoimmunity due to molecular mimicry between pathogen and host proteins. The individualized nature of PASC symptoms suggests that different therapeutic approaches may be required to best manage specific patients.

Pathogenic mechanisms of post-acute sequelae of SARS-CoV-2 infection (PASC)

COVID-19, with persistent and new onset of symptoms such as fatigue, post-exertional malaise, and cognitive dysfunction that last for months and impact everyday functioning, is referred to as Long COVID under the general category of post-acute sequelae of SARS-CoV-2 infection (PASC). PASC is highly heterogenous and may be associated with multisystem tissue damage/dysfunction including acute encephalitis, cardiopulmonary syndromes, fibrosis, hepatobiliary damages, gastrointestinal dysregulation, myocardial infarction, neuromuscular syndromes, neuropsychiatric disorders, pulmonary damage, renal failure, stroke, and vascular endothelial dysregulation. A better understanding of the pathophysiologic mechanisms underlying PASC is essential to guide prevention and treatment. This review addresses potential mechanisms and hypotheses that connect SARS-CoV-2 infection to long-term health consequences. Comparisons between PASC and other virus-initiated chronic syndromes such as myalgic encephalomyelitis/chronic fatigue syndrome and postural orthostatic tachycardia syndrome will be addressed. Aligning symptoms with other chronic syndromes and identifying potentially regulated common underlining pathways may be necessary for understanding the true nature of PASC. The discussed contributors to PASC symptoms include sequelae from acute SARS-CoV-2 injury to one or more organs, persistent reservoirs of the replicating virus or its remnants in several tissues, re-activation of latent pathogens such as Epstein-Barr and herpes viruses in COVID-19 immune-dysregulated tissue environment, SARS-CoV-2 interactions with host microbiome/virome communities, clotting/coagulation dysregulation, dysfunctional brainstem/vagus nerve signaling, dysautonomia or autonomic dysfunction, ongoing activity of primed immune cells, and autoimmunity due to molecular mimicry between pathogen and host proteins. The individualized nature of PASC symptoms suggests that different therapeutic approaches may be required to best manage specific patients.

Inmunohistochemical detection of pandemic SARSCoV- 2 antigens in lung tissue

The COVID-19 pandemic caused by the SARS-CoV-2 virus has generated globally more than 110.7 million infections and 2.4 million deaths. The severity of this infection can range from asymptomatic, mild to severe.To know the possible associations between the presence of the virus and histopathological alterations found in tissues of fatal cases of COVID-19, the presence of the virus in the lung tissue of a patient with a clinical history of SARS-CoV-2 infection was evaluated.Lung tissue was histologically processed for immunohistochemical detection of SARSCoV-2. In the histopathological study, morphological changes associated with pneumonitis of viral origin were observed. Likewise, the location of the SARS-CoV-2 virus was observed mainly in the cytoplasm of the cells of the inflammatory infiltrate.

Bradykinin and Galectin-3 in Survived and Deceased Patients with COVID-19 Pneumonia: An Increasingly Promising Biochemical Target

Introduction

There are still no definite curative or preventive strategies for COVID-19 disease. It is crucial to fully comprehend the pathogenesis of COVID-19 infection so that we can develop expedient pharmacological protocols. While the impact of cytokine storm on COVID-19 severity has been one of the most tested hypotheses, the role of bradykinin and various other oxidative stress markers has been relatively under-researched. Their levels can be determined immediately after a hospital admission so they could be used as early predictors of the further development of the disease.

Aim

The study aims at evaluating the possibility of using bradykinin and galectin-3 levels as early predictors that COVID-19 disease will progress into a severe case. Material and methods. The study was conducted as a prospective cross-sectional study. It included 47 consecutive adult patients with confirmed SARS-CoV-2 infection and COVID-19 pneumonia. All study subjects were admitted for a hospital treatment to the tertiary Clinical Hospital Center Bezanijska kosa, Belgrade, Serbia on June 2021. The blood samples were collected at the patients' admission. The analyses of demographic, radiological, and clinical data were later conducted for both groups (the deceased patients and those who survived). In addition, we analyzed the potential relations between the outcome and the levels of bradykinin and galectin-3 measured immediately after the patients were admitted to the hospital.

Results

The patients who passed away were predominantly older men with comorbidities. We recorded higher CT scores in the deceased patients and the significantly higher levels of urea, creatinine, CK, troponine, CRP, and other laboratory markers. They stayed at the ICU unit longer and required mechanical ventilation more frequently than the patients who survived. On the other hand, no differences were recorded in the time periods passing from the onset of the systems to the hospital admissions. Finally, we can highlight several independent predictors of mortality in patients with COVID-19 pneumonia, including the following: (1) patients who are 50 or more years old, (2) with in-hospital stays are longer that 4 days, (3) bradykinin levels surpass 220000 pg/ml, (4) D-dimer, creatinine, and CRP are elevated, and (5) comorbidities were present (such as hypertension and diabetes).

Conclusion

The present study strongly supports the bradykinin storm hypothesis. Since elevated bradykinin levels have been found in most COVID-19 cases with fatal outcomes, the future therapeutical strategies for COVID-19 have to be focused on reducing bradykinin serum concentrations.

Extensive Cerebral Venous Thrombosis as an Isolated Presentation in a COVID-19-Positive Young Adult

Due to the increase in the number of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) cases globally, more medical case reports are being published showing the different complications of coronavirus disease 2019 (COVID-19). One of the important complications is thrombotic events that occur as a sequela of COVID-19. Here we present a case of a previously healthy male patient in his 30s who presented to the emergency unit experiencing headaches, vomiting, and weakness in his left arm. On examination, he was vitally stable, and fully oriented, but noted to have jerky movements of the left arm; therefore, he was sent for a CT brain scan. Shortly after, he developed a generalized tonic-clonic seizure. After stabilizing the patient, CT brain with cerebral venography was done, which revealed extensive thrombosis of the superior sagittal sinus and bilateral superficial cortical veins. The patient's blood test showed a high D-dimer (4.90 ug/ml), and the COVID-19 polymerase chain reaction (PCR) swab test was positive. It is commonly known that COVID-19 infection presents with fever and respiratory symptoms; however, our case illustrates the thrombotic complication of SARS-CoV-2 infection with no pneumonia or respiratory symptoms with a high level of d-dimer.

A systematic review of biomarkers among hospitalized patients with COVID-19 predictive of venous thromboembolism: A communication from the Predictive and Diagnostic Variables Scientific and Standardization Committee of the ISTH

Background

Thrombosis is reported to occur more often among patients with COVID-19 than otherwise expected in the setting of viral pneumonia and sepsis. Systemic inflammatory biomarkers may be associated with venous thromboembolism (VTE) risk. The ISTH subcommittee on Predictive and Diagnostic Variables in Thrombotic Disease aimed to report the evidence on prognostic biomarkers for VTE in hospitalized patients with COVID-19.

Methods

Using a standardized Preferred Reporting Items for Systematic Reviews and Meta-analysis methodology, we conducted a systematic literature review to identify studies reporting prognostic biomarkers for VTE among hospitalized patients with COVID-19. Eligible studies included adults hospitalized with COVID-19 and reported the prognostic associations between any biomarker measured on admission, and the subsequent diagnosis of deep vein thrombosis or pulmonary embolism. Two authors reviewed titles and abstracts, and three authors extracted study data and performed review of bias. Results were displayed descriptively. Meta-analysis was not possible.

Results

From the initial 196 identified studies, full-text review was performed for 72 studies. Admission D-dimer levels were associated with VTE during hospitalization in five studies, and elevated platelet count was associated with VTE during hospitalization in one study. The risk of bias ranged from low to high for included studies. Overall, there was a paucity of high-quality prognostic studies. Studies on other biomarkers did not meet the systematic review inclusion criteria.

Conclusions

Admission D-dimer was associated with VTE diagnosis during hospitalization for COVID-19; however, prospective validation of this finding is needed to identify optimal D-dimer thresholds to guide VTE prophylaxis measures.

COVID-19 related thrombosis: A mini-review

Introduction

COVID-19 associated VTE is a new disease entity with high morbidity and mortality. The aim of this paper is to review contemporary emerging literature on the incidence, pathophysiology, predictive prognostic indicators, and management consensus for Covid-19 related thrombotic complications, in particular DVT and PE.

Methods

A literature review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. All searches were done via PubMed. References of review articles were further screened according to the exclusion criteria.

Results

In total, 154 records were identified and 20 duplicates were removed. A final 68 articles were included in the qualitative analysis. COVID-19 related thrombosis can affect multiple organs of the body, presenting in the form of arterial or venous thrombosis such as ischemic stroke, myocardial infarction, mesenteric ischemia, limb ischemia, DVT, or PE. DVT and PE has an overall incidence of 6–26%, and severely ill COVID-19 patients have even higher incidence of thromboembolism. On the other hand, incidence of arterial thromboembolism is much lower with incidence of 0.7%–3.7%. D-dimer is found to be an independent risk factor, and IMPROVE score, Caprini score, and Padua score have all been used as predictors. International guidelines suggest the use of low molecular weight heparin (LMWH) or fondaparinux for prophylaxis of VTE, and therapeutic dosage of weight adjusted LMWH for treatment if confirmed diagnosis.

Conclusions

Contemporary rapidly evolving evidence shows that COVID-19 associated thrombosis was a novel clinical entity, especially in severely ill COVID-19 patients. There are multiple society-driven guidelines only, but without any level 1 evidence for management regimen. The ideal dose for prophylaxis is not established and may vary depending on balance of bleeding and thrombosis risk. The risk of bleeding may be increased in patients in intensive care unit.

Upregulation of cytokine signalling in platelets increases risk of thrombophilia in severe COVID-19 patients

Abnormal coagulation dynamics, including disseminated intravascular coagulopathy, pulmonary embolism, venous thromboembolism and risk of thrombosis are often associated with the severity of COVID-19. However, very little is known about the contribution of platelets in above pathogenesis. In order to decipher the pathophysiology of thrombophilia in COVID-19, we recruited severely ill patients from ICU, based on the above symptoms and higher D-dimer levels, and compared these parameters with their asymptomatic counterparts. Elevated levels of platelet-derived microparticles and platelet-leukocyte aggregates suggested the hyperactivation of platelets in ICU patients. Strikingly, platelet transcriptome analysis showed a greater association of IL-6 and TNF signalling pathways in ICU patients along with higher plasma levels of IL-6 and TNFα. In addition, upregulation of pathways like blood coagulation and hemostasis, as well as inflammation coexisted in platelets of these patients. Further, the increment of necrotic pathway and ROS-metabolic processes in platelets was suggestive of its procoagulant phenotype in ICU patients. This study suggests that higher plasma IL-6 and TNFα may trigger platelet activation and coagulation, and in turn aggravate thrombosis and hypercoagulation in severe COVID-19 patients. Therefore, the elevated IL-6 and TNFα, may serve as potential risk factors for platelet activation and thrombophilia in these patients.

Coagulopathy and Fibrinolytic Pathophysiology in COVID-19 and SARS-CoV-2 Vaccination

Coronavirus Disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and is frequently complicated by thrombosis. In some cases of severe COVID-19, fibrinolysis may be markedly enhanced within a few days, resulting in fatal bleeding. In the treatment of COVID-19, attention should be paid to both coagulation activation and fibrinolytic activation. Various thromboses are known to occur after vaccination with SARS-CoV-2 vaccines. Vaccine-induced immune thrombotic thrombocytopenia (VITT) can occur after adenovirus-vectored vaccination, and is characterized by the detection of anti-platelet factor 4 antibodies by enzyme-linked immunosorbent assay and thrombosis in unusual locations such as cerebral venous sinuses and visceral veins. Treatment comprises high-dose immunoglobulin, argatroban, and fondaparinux. Some VITT cases show marked decreases in fibrinogen and platelets and marked increases in D-dimer, suggesting the presence of enhanced-fibrinolytic-type disseminated intravascular coagulation with a high risk of bleeding. In the treatment of VITT, evaluation of both coagulation activation and fibrinolytic activation is important, adjusting treatments accordingly to improve outcomes.

The analysis of Fe-dependent serum enzymes in severe COVID-19 with a pulmonary thrombotic event

Introduction

COVID-19 patients in critical condition requiring ICU admission are more likely to experience thromboembolic complications, especially pulmonary embolism. Since the outbreak of coronavirus disease 2019 (COVID-19), clinicians have struggled with the attempt to diagnose and manage the severe and fatal complications of COVID-19 appropriately. Several reports have described significant procoagulatory events, including life-threatening pulmonary embolism, in these patients. The aim of the study was to analyze the results of selected serum enzymes in patients with a radiologically confirmed pulmonary thrombotic event based on the pulmonary tissue involvement assessed in a computed tomography (CT) scan.

Material and methods

The retrospective study covered a group of 226 COVID-19 patients. Groups were divided based on the degree of lung tissue involvement in CT examinations, including patients with confirmed pulmonary embolism. The analyzed group consisted of 136 men and 90 women with mean age of 70 years.

Results

The group consisted of patients with < 50% of lung volume changes who had higher parameter values in each analyzed parameter, except red blood cells (RBC) (p < 0.05). Especially, the level of ferritin was much higher in the first group (p = 0.000008). Elevated ferritin levels were observed in all patients with lung tissue involvement.

Discussion

This line of research is critical in order to assess the predisposing conditions for pulmonary embolism occurrence in COVID-19, which can be used as a predictive factor for course of the disease. The conducted research will resolve whether there is a relationship between the selected laboratory parameters and the occurrence of pulmonary embolism in patients with COVID-19.

Conclusions

The study demonstrated that elevated levels of several inflammatory and thrombotic parameters such as ferritin, D-dimer, C-reactive protein (CRP) as well as hemoglobin do not correlate with the degree of lung tissue involvement in the computed tomography image.

Plasminogen gene polymorphisms [c.924C>T and IVS 8+14 G>A] in periodontitis and familial Mediterranean fever: A case-control study

BACKGROUND AND OBJECTIVE

The plasminogen (PLG) activation system plays an essential role in severe inflammation based diseases such as periodontitis, destructive membranous periodontal disease (ligneous periodontitis), familial Mediterranean fever (FMF), and amyloidosis. We have aimed to evaluate variations in PLG and the associations between PLG and MEFV genotypes in patients with FMF/ FMF-related secondary amyloidosis and periodontitis.

MATERIAL AND METHODS

A total of 247 individuals who were either diagnosed with FMF or systemically healthy were recruited to this human observational study with a cross-sectional design. All individuals were also diagnosed with periodontitis or periodontally healthy. Blood samples were obtained from patients with FMF and systemically healthy controls. Clinical periodontal indicators were recorded. All polymorphisms located in exons 6 and 8 of PLG and mutations located on exons 2 and 10 of the MEFV gene were analyzed by DNA Sanger Sequencing. Genotypes and allele frequencies of PLG and MEFV were detected and tested by the Hardy-Weinberg equilibrium. Serum levels of amyloid A (SAA), high-sensitive C-reactive protein (hs-CRP), PLG, and salivary PLG levels were determined by using enzyme-linked immunosorbent assay (ELISA).

RESULTS

Two polymorphisms were identified in PLG: G to A polymorphism on the 14th nucleotide of intron 8 and C to T polymorphism on the 924th nucleotide of the coding region (IVS 8+14 G>A and c.924C>T, respectively). In IVS 8+14 G>A polymorphisms, wild-type genotype: GG, heterozygote genotype: GA and homozygote genotype: AA. In c.924C>T polymorphism, wild-type genotype: CC, heterozygote genotype: CT and homozygote genotype: TT. The frequency of the heterozygous polymorphisms of PLG was significantly increased (17.6%) in FMF patients with periodontitis (p = .027). A large proportion of the test group that was heterozygous for MEFV-R202Q also had heterozygous PLG polymorphisms. Remarkable exacerbation in periodontal parameters was observed in patients with FMF and amyloidosis. SAA and hs-CRP levels were significantly correlated with salivary PLG levels in patients with periodontitis and heterozygous PLG.

CONCLUSIONS

The current study describes IVS 8+14 G>A (rs2295368) and c.924C>T (rs1380916375) polymorphisms for the first time in the periodontal literature, which might play an important role in the pathogenesis of periodontitis, FMF, or amyloidosis. The elucidation of PLG polymorphisms is beneficial from a public health perspective by increasing the quality of life in these patients and reducing the mortality and morbidity associated with inflammatory diseases such as periodontal disease, FMF, and FMF-related amyloidosis.

Elderly Population with COVID-19 and the Accuracy of Clinical Scales and D-Dimer for Pulmonary Embolism: The OCTA-COVID Study

BACKGROUND

Elderly COVID-19 patients have a high risk of pulmonary embolism (PE), but factors that predict PE are unknown in this population. This study assessed the Wells and revised Geneva scoring systems as predictors of PE and their relationships with D-dimer (DD) in this population.

METHODS

This was a longitudinal, observational study that included patients ≥75 years old with COVID-19 and suspected PE. The performances of the Wells score, revised Geneva score and DD levels were assessed. The combinations of the DD level and the clinical scales were evaluated using positive rules for higher specificity.

RESULTS

Among 305 patients included in the OCTA-COVID study cohort, 50 had suspected PE based on computed tomography pulmonary arteriography (CTPA), and the prevalence was 5.6%. The frequencies of PE in the low-, intermediate- and high-probability categories were 5.9%, 88.2% and 5.9% for the Geneva model and 35.3%, 58.8% and 5.9% for the Wells model, respectively. The DD median was higher in the PE group (4.33 mg/L; interquartile range (IQR) 2.40-7.17) than in the no PE group (1.39 mg/L; IQR 1.01-2.75) (p < 0.001). The area under the curve (AUC) for DD was 0.789 (0.652-0.927). After changing the cutoff point for DD to 4.33 mg/L, the specificity increased from 42.5% to 93.9%.

CONCLUSIONS

The cutoff point DD > 4.33 mg/L has an increased specificity, which can discriminate false positives. The addition of the DD and the clinical probability scales increases the specificity and negative predictive value, which helps to avoid unnecessary invasive tests in this population.

Divergent impacts of tocilizumab and colchicine in COVID-19-associated coagulopathy: the role of alpha-defensins

Patients who are severely affected by coronavirus disease 2019 (COVID-19) may develop a delayed onset 'cytokine storm', which includes an increase in interleukin-6 (IL-6). This may be followed by a pro-thrombotic state and increased D-dimers. It was anticipated that tocilizumab (TCZ), an anti-IL-6 receptor monoclonal antibody, would mitigate inflammation and coagulation in patients with COVID-19. However, clinical trials with TCZ have recorded an increase in D-dimer levels. In contrast to TCZ, colchicine reduced D-dimer levels in patients with COVID-19. To understand how the two anti-inflammatory agents have diverse effects on D-dimer levels, we present data from two clinical trials that we performed. In the first trial, TCZ was administered (8 mg/kg) to patients who had a positive polymerase chain reaction test for COVID-19. In the second trial, colchicine was given (0·5 mg twice a day). We found that TCZ significantly increased IL-6, α-Defensin (α-Def), a pro-thrombotic peptide, and D-dimers. In contrast, treatment with colchicine reduced α-Def and Di-dimer levels. In vitro studies show that IL-6 stimulated the release of α-Def from human neutrophils but in contrast to colchicine, TCZ did not inhibit the stimulatory effect of IL-6; raising the possibility that the increase in IL-6 in patients with COVID-19 treated with TCZ triggers the release of α-Def, which promotes pro-thrombotic events reflected in an increase in D-dimer levels.

Similarities between COVID-19 and systemic sclerosis early vasculopathy: A "viral" challenge for future research in scleroderma

OBJECTIVE

To review similarities between COVID-19 and systemic sclerosis (SSc) early vasculopathy to provide novel insights into both diseases.

METHODS

A narrative review of the literature supplemented with expert opinion.

RESULTS

There is clear evidence that the endothelium is at the centre stage in SSc and COVID-19, with endothelial cell activation/injury and dysfunction creating the crucial evolving step in the pathogenesis of both diseases. The angiotensin system has also been implicated in the early stages of both COVID-19 and SSc. Autoptic studies provide novel insights into the effects of SARS-CoV-2 on the endothelium. Normal endothelium and endothelial dysfunction in COVID-19 and SSc are discussed. It is debated whether SARS-CoV-2 infection triggers autoimmunity with production of autoantibodies which is of mechanistic interest because other viral illnesses are potentially involved in endothelial dysfunction and in SSc pathogenesis.

CONCLUSION

COVID-19 is due to a direct assault of SARS-CoV-2 on the vascular system as an acute infection, whereas SSc remains a chronic/sub-acute autoimmune disease of largely unknown etiology Further study and exploration of the SARS-CoV-2 pathogenic mechanisms might provide further useful milestones in the understanding of the early SSc pathogenesis.

A Level 1 Trauma Center's response to the COVID-19 pandemic in New York City: a qualitative and quantitative story

BACKGROUND

The purpose of this study is to describe a Level 1 Trauma Center's orthopedic response to the COVID-19 pandemic, and to compare outcomes of acute fracture patients pre-COVID versus during the COVID-19 pandemic.

METHODS

All inpatient fracture cases performed over a 5-month period were identified and retrospective chart review performed. Patients were divided into pre- and COVID-era groups based on when surgery was performed relative to March 16, 2020 (the date elective operations were ceased), and groups were statistically compared. Patients with a COVID test result were further sub-divided into COVID negative and positive groups, and statistically compared. Statistical analysis was performed using independent t-test for continuous variables and chi-square analysis for categorical variables.

RESULTS

One hundred and nineteen patients were identified, 38% females with average age of 58 years. Average length of stay was 7 days with average time from injury to surgery of 3 days and average time from admission to surgery of 1.3 days. Overall in-hospital complication rate was 29.4%, and 30-day mortality and readmission rates were 2.5% and 5%, respectively. Sixty-nine patients comprised the pre-COVID group, and 50 in the COVID-era group. There was no significant difference with respect to length of stay, time from injury to surgery, time from admission to surgery, need for post-operative ICU stay, in-hospital complication rate, 30-day mortality rate and 30-day readmission rate. Thirty-four patients had COVID testing, with 24 negative and 10 positive. COVID-positive patients had longer time from injury to surgery (8.5 days vs. 2 days, p = 0.003) and longer time from admission to surgery (2.7 days vs. 1.2 days, p = 0.034). While more COVID-positive patients required ICU admission post-operatively (60% vs. 21%, p = 0.036), there was no difference in overall complication rate.

CONCLUSIONS

Orthopedic care of acute fracture patients was not affected by a global pandemic. The response of our Level 1 Trauma Center's orthopedic department can guide other hospitals if and when new surges in COVID cases arise, in order to prevent compromising appropriate orthopedic care.

LEVEL OF EVIDENCE

Prognostic III.

Mouse Models for the Study of SARS-CoV-2 Infection

Mice are an invaluable resource for studying virus-induced disease. They are a small, genetically modifiable animal for which a large arsenal of genetic and immunologic tools is available for evaluation of pathogenesis and potential vaccines and therapeutics. SARS-CoV-2, the betacoronavirus responsible for the COVID-19 pandemic, does not naturally replicate in wild-type mice, due to structural differences between human and mouse ACE2, the primary receptor for SARS-CoV-2 entry into cells. However, several mouse strains have been developed that allow for SARS-CoV-2 replication and clinical disease. Two broad strategies have primarily been deployed for developing mouse strains susceptible to COVID-19-like disease: adding in the human ACE2 gene and adapting the virus to the mouse ACE2 receptor. Both approaches result in mice that develop several of the clinical and pathologic hallmarks of COVID-19, including acute respiratory distress syndrome and acute lung injury. In this review, we describe key acute pulmonary and extrapulmonary pathologic changes seen in COVID-19 patients that mouse models of SARS-CoV-2 infection ideally replicate, the essential development of mouse models for the study of Severe Acute Respiratory Syndrome and Middle Eastern Respiratory Syndrome and the basis of many of the models of COVID-19, and key clinical and pathologic features of currently available mouse models of SARS-CoV-2 infection.

Systemic inflammation in COVID‐19 patients may induce various types of venous and arterial thrombosis: A systematic review

COVID‐19 is a global pandemic with a daily increasing number of affected individuals. Thrombosis is a severe complication of COVID‐19 that leads to a worse clinical course with higher rates of mortality. Multiple lines of evidence suggest that hyperinflammation plays a crucial role in disease progression. This review compiles clinical data of COVID‐19 patients who developed thrombotic complications to investigate the possible role of hyperinflammation in inducing hypercoagulation. A systematic literature search was performed using PubMed, Embase, Medline and Scopus to identify relevant clinical studies that investigated thrombotic manifestations and reported inflammatory and coagulation biomarkers in COVID‐19 patients. Only 54 studies met our inclusion criteria, the majority of which demonstrated significantly elevated inflammatory markers. In the cohort studies with control, D‐dimer was significantly higher in COVID‐19 patients with thrombosis as compared to the control. Pulmonary embolism, deep vein thrombosis and strokes were frequently reported which could be attributed to the hyperinflammatory response associated with COVID‐19 and/or to the direct viral activation of platelets and endothelial cells, two mechanisms that are discussed in this review. It is recommended that all admitted COVID‐19 patients should be assessed for hypercoagulation. Furthermore, several studies have suggested that anticoagulation may be beneficial, especially in hospitalized non‐ICU patients. Although vaccines against SARS‐CoV‐2 have been approved and distributed in several countries, research should continue in the field of prevention and treatment of COVID‐19 and its severe complications including thrombosis due to the emergence of new variants against which the efficacy of the vaccines is not yet clear.

Vitamin D and Platelets: A Menacing Duo in COVID-19 and Potential Relation to Bone Remodeling

Global data correlate severe vitamin D deficiency with COVID-19-associated coagulopathy, further suggesting the presence of a hypercoagulable state in severe COVID-19 patients, which could promote thrombosis in the lungs and in other organs. The feedback loop between COVID-19-associated coagulopathy and vitamin D also involves platelets (PLTs), since vitamin D deficiency stimulates PLT activation and aggregation and increases fibrinolysis and thrombosis. Vitamin D and PLTs share and play specific roles not only in coagulation and thrombosis but also during inflammation, endothelial dysfunction, and immune response. Additionally, another ‘fil rouge’ between vitamin D and PLTs is represented by their role in mineral metabolism and bone health, since vitamin D deficiency, low PLT count, and altered PLT-related parameters are linked to abnormal bone remodeling in certain pathological conditions, such as osteoporosis (OP). Hence, it is possible to speculate that severe COVID-19 patients are characterized by the presence of several predisposing factors to bone fragility and OP that may be monitored to avoid potential complications. Here, we hypothesize different pervasive actions of vitamin D and PLT association in COVID-19, also allowing for potential preliminary information on bone health status during COVID-19 infection.

Simultaneous Giant cavity pulmonary lesion and pneumothorax following COVID-19 pneumonia

Cavitary lung formation with spontaneous pneumothorax has been rarely reported as a complication of COVID-19 pneumonia. We report a rare case of a 38 years-old male patient affected by COVID-19 pneumonia, exceptionally complicated by a simultaneous giant cavity in the right upper lung and a small right pneumothorax in the right hemithorax. Whilst pneumothorax emphysema, giant bullae and pneumothorax with alveolar rupture are known to potentially develop in COVID-19 patients as a result of high-flow O2 support, the exact origin of the giant lung cavitation in our patient could be not confirmed. Cavitary lesions - featured by high mortality rate - are reportedly associated with lung infarctions and can be the aftermaths of pulmonary embolism, a rather common sequela of COVID-19 pneumonia. Radiological imaging is critical to support clinical decision making in the management of COVID-19 pneumonia, since not only it can visualize and stage the disease, but it can also detect and monitor the eventual onset of complications over time, even following patient discharge from hospital.

Neutrophil Extracellular Traps (NETs) in Severe SARS-CoV-2 Lung Disease

Neutrophil extracellular traps (NETs), built from mitochondrial or nuclear DNA, proteinases, and histones, entrap and eliminate pathogens in the course of bacterial or viral infections. Neutrophils’ activation and the formation of NETs have been described as major risk factors for acute lung injury, multi-organ damage, and mortality in COVID-19 disease. NETs-related lung injury involves both epithelial and endothelial cells, as well as the alveolar-capillary barrier. The markers for NETs formation, such as circulating DNA, neutrophil elastase (NE) activity, or myeloperoxidase-DNA complexes, were found in lung specimens of COVID-19 victims, as well as in sera and tracheal aspirates obtained from COVID-19 patients. DNA threads form large conglomerates causing local obstruction of the small bronchi and together with NE are responsible for overproduction of mucin by epithelial cells. Various components of NETs are involved in the pathogenesis of cytokine storm in SARS-CoV-2 pulmonary disease. NETs are responsible for the interplay between inflammation and thrombosis in the affected lungs. The immunothrombosis, stimulated by NETs, has a poor prognostic significance. Better understanding of the role of NETs in the course of COVID-19 can help to develop novel approaches to the therapeutic interventions in this condition.

COVID-19 in Pregnancy: Implication on Platelets and Blood Indices

OBJECTIVE

 To describe the hematological changes, the platelet indices in particular, in pregnant women with coronavirus disease 2019 (COVID-19) compared to healthy pregnant women.

METHODS

 A retrospective case-control study conducted at the Al Yarmouk Teaching Hospital, in Baghdad, Iraq, involving 100 pregnant women, 50 with positive viral DNA for COVID-19 (case group), and 50 with negative results (control group); both groups were subjected to a thorough hematological evaluation.

RESULTS

 Among the main hematological variables analyzed, the platelet indices, namely the mean platelet volume (MPV) and the platelet distribution width (PDW), showed statistically significant differences (MPV: 10.87 ± 66.92 fL for the case group versus 9.84 ± 1.2 fL for the control group; PDW: 14.82 ± 3.18 fL for the case group versus 13.3 ± 2.16 fL for the controls). The criterion value of the receiver operating characteristic (ROC) curve for PDW at a cutoff point of > 11.8 fL showed a weak diagnostic marker, while the MPV at a cutoff value of > 10.17 fL showed a good diagnostic marker.

CONCLUSION

 The MPV and PDW are significantly affected by the this viral infection, even in asymptomatic confirmed cases, and we recommend that both parameters be included in the diagnostic panel of this infection.

Medical treatment for paradoxical and saddle pulmonary embolism in a young man with patent foramen ovale and coronavirus disease 2019

Here, we reported a 32-year-old male presenting to the emergency department with respiratory symptoms and coronavirus disease 2019 (COVID-19) diagnosis. Multiple thrombi were detected in his heart and inferior vena cava, probably due to former deep-vein thrombosis. The presence of patent foramen ovale and high pressure of the right heart caused the clots to enter the heart's left side. He received fibrinolytics, and his condition improved with no need for surgery. Hence, patients with impending paradoxical embolism may take advantage of medical treatment, such as fibrinolytics. Moreover, COVID-19 appears to be associated with a strong thrombotic tendency, and anticoagulants might be helpful.

Predictive Factors of Pulmonary Embolism in Older Patients with SARS-CoV-2: The OCTA-COVID-19 Study

Background: The risk of pulmonary embolism (PE) has not been studied in older patients affected by COVID-19. We aimed to assess PE incidence and risk factors in a population of older patients infected with SARS-CoV-2. Methods: An ambispective, observational cohort study. A total of 305 patients ≥ 75 years old had the SARS-CoV-2 infection from March to May 2020. The incidence rate of PE was estimated as the proportion of new cases within the whole sample. Youden’s index was used to assess the cutoff point of D-dimer. To select factors associated with the risk of PE, time-to-event analyses were performed using cause-specific hazard models. Results: In total, 305 patients with a median age of 87 years (62.3% female) were studied; 67.9% were referred from nursing homes and 90.4% received any type of anticoagulation. A total of 64.9% showed frailty and 44% presented with dementia. The PE incidence was 5.6%. The cutoff value of a D-dimer level over 2.59 mg/L showed a sensitivity of 82.4% and specificity of 73.8% in discriminating a PE diagnosis. In the multivariate analysis, the factors associated with PE were previous oncological events and D-dimer levels. Conclusions: The PE incidence was 5.6%, and major risk factors for PE were oncological antecedents and increased plasma D-dimer levels.

Prevalence of Thromboembolic Complications in COVID-19 Infection: A Systematic Review and Meta-Analysis

Introduction: The coronavirus disease (COVID-19) infection is proved to be involved in the onset of thromboembolism episodes. This study aims to evaluate the prevalence of thromboembolic complications in patients with COVID-19 from March until May 2020. Methods: A literature review was conducted in MEDLINE (via PubMed), Scopus, Embase, Cochrane, and CINHAL without any language and date of publication restriction (Prospero registration number CRD42020186925). The inclusion criteria were as following: 1) patients with diagnosis of COVID-19; 2) occurrence of thromboembolic event, and 3) patients older than 18 years of age. A multi-variable random effects model was computed accounting for correlations among outcomes by considering a heterogeneous compound symmetry covariance matrix. Results: Observational studies included 2,442 participants from 268 to 7,999 participants per study, 1,014 (41.52%) were male and 825 (33.78%) were female. The multi-variable pooled event rate of acute myocardial infarction was rare, estimated to be 0.03 (95% confidence interval [CI]: 0.00–0.07; p=0.23); this is also true for the meta-analytical estimate of disseminated intravascular disease which was 0.04 (95% CI: 0.00–0.08; p=0.03). Conversely, other events were found to be more frequent. Indeed, the pooled proportion of pulmonary embolism was 0.14 (95% CI: 0.08–0.20; p<0.001), while the venous thromboembolic event rate is 0.15 (95% CI: 0.09-0.30; p=0.04). The pooled intrahospital mortality rate was equal to 0.12 (95% CI: 0.08–0.16; p<0.001). Conclusions: Thromboembolic events, particularly venous thromboembolic event rate and pulmonary embolism, are a frequent complication in patients hospitalised with COVID-19. These findings suggest that the threshold for clinical suspicion should be low to trigger prompt diagnostic testing and that evaluation of therapeutic treatment should be considered in patients in intensive care units with COVID-19.

Pathophysiologic mechanisms of cerebral endotheliopathy and stroke due to Sars-CoV-2

Cerebrovascular events have emerged as a central feature of the clinical syndrome associated with Sars-CoV-2 infection. This increase in infection-related strokes is marked by atypical presentations including stroke in younger patients and a high rate of hemorrhagic transformation after ischemia. A variety of pathogenic mechanisms may underlie this connection. Efforts to identify synergism in the pathophysiology underlying stroke and Sars-CoV-2 infection can inform the understanding of both conditions in novel ways. In this review, the molecular cascades connected to Sars-CoV-2 infection are placed in the context of the cerebral vasculature and in relationship to pathways known to be associated with stroke. Cytokine-mediated promotion of systemic hypercoagulability is suggested while direct Sars-CoV-2 infection of cerebral endothelial cells may also contribute. Endotheliopathy resulting from direct Sars-CoV-2 infection of the cerebral vasculature can modulate ACE2/AT1R/MasR signaling pathways, trigger direct viral activation of the complement cascade, and activate feed-forward cytokine cascades that impact the blood-brain barrier. All of these pathways are already implicated as independent mechanisms driving stroke and cerebrovascular injury irrespective of Sars-CoV-2. Recognizing the overlap of molecular pathways triggered by Sars-CoV-2 infection with those implicated in the pathogenesis of stroke provides an opportunity to identify future therapeutics targeting both Sars-CoV-2 and stroke thereby reducing the impact of the global pandemic.

Lung Epithelial Cell Transcriptional Regulation as a Factor in COVID-19-associated Coagulopathies

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly become a global pandemic. In addition to the acute pulmonary symptoms of coronavirus disease (COVID-19) (the disease associated with SARS-CoV-2 infection), pulmonary and distal coagulopathies have caused morbidity and mortality in many patients. Currently, the molecular pathogenesis underlying COVID-19-associated coagulopathies are unknown. Identifying the molecular basis of how SARS-CoV-2 drives coagulation is essential to mitigating short- and long-term thrombotic risks of sick and recovered patients with COVID-19. We aimed to perform coagulation-focused transcriptome analysis of in vitro infected primary respiratory epithelial cells, patient-derived bronchial alveolar lavage cells, and circulating immune cells during SARS-CoV-2 infection. Our objective was to identify transcription-mediated signaling networks driving coagulopathies associated with COVID-19. We analyzed recently published experimentally and clinically derived bulk or single-cell RNA sequencing datasets of SARS-CoV-2 infection to identify changes in transcriptional regulation of blood coagulation. We also confirmed that the transcriptional expression of a key coagulation regulator was recapitulated at the protein level. We specifically focused our analysis on lung tissue-expressed genes regulating the extrinsic coagulation cascade and the plasminogen activation system. Analyzing transcriptomic data of in vitro infected normal human bronchial epithelial cells and patient-derived bronchial alveolar lavage samples revealed that SARS-CoV-2 infection induces the extrinsic blood coagulation cascade and suppresses the plasminogen activation system. We also performed in vitro SARS-CoV-2 infection experiments on primary human lung epithelial cells to confirm that transcriptional upregulation of tissue factor, the extrinsic coagulation cascade master regulator, manifested at the protein level. Furthermore, infection of normal human bronchial epithelial cells with influenza A virus did not drive key regulators of blood coagulation in a similar manner as SARS-CoV-2. In addition, peripheral blood mononuclear cells did not differentially express genes regulating the extrinsic coagulation cascade or plasminogen activation system during SARS-CoV-2 infection, suggesting that they are not directly inducing coagulopathy through these pathways. The hyperactivation of the extrinsic blood coagulation cascade and the suppression of the plasminogen activation system in SARS-CoV-2-infected epithelial cells may drive diverse coagulopathies in the lung and distal organ systems. Understanding how hosts drive such transcriptional changes with SARS-CoV-2 infection may enable the design of host-directed therapeutic strategies to treat COVID-19 and other coronaviruses inducing hypercoagulation.

Reduced macular vessel density in COVID-19 patients with and without associated thrombotic events using optical coherence tomography angiography

Purpose

Thrombotic events (TE) represent one of the major complications of SARS-CoV-2 infection. The objective is to evaluate vessel density (VD) and perfusion density (PD) by optical coherence tomography angiography (OCTA) in COVID-19 patients, and compare the findings with healthy controls. The secondary objective is to evaluate if there are differences in OCTA parameters between COVID-19 patients with and without associated TE.

Methods

Cross-sectional case–control study that included patients with laboratory-confirmed diagnosis of COVID-19 with and without TE related to the infection and age-matched healthy controls. Ophthalmological examination and OCTA were performed 12 weeks after diagnosis. Demographic data and medical history were collected. Macular OCTA parameters in the superficial retinal plexus were analyzed according to ETDRS sectors.

Results

Ninety patients were included, 19 (20%) COVID-19 patients with associated TE, 47 (49.5%) COVID-19 patients without TE, and 29 (30.5%) healthy controls. Fifty-three (55.7%) were male, mean age 54.4 (SD 10.2) years. COVID-19 patients presented significantly lower VD than healthy controls: central (p = 0.003), inner ring (p = 0.026), outer ring (p = 0.001). PD was also significantly decreased: outer ring (p = 0.003), full area (p = 0.001). No differences in OCTA parameters were found between COVID-19 patients with and without TE.

Conclusions

OCTA represents a promising tool for the in vivo assessment of microvascular changes in COVID-19. Patients with SARS-CoV-2 infection show lower VD and PD compared to healthy controls. However, no differences were found between COVID-19 when considering TE. Prospective studies are required to further evaluate the retinal microvascular involvement of SARS-CoV-2 and its impact on the vasculature of other organs.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00417-021-05186-0.

Severe COVID-19 and coagulopathy: A systematic review and meta-analysis

Introduction: Coronavirus disease 2019 (COVID-19)-induced coagulopathy (CIC) has been widely reported in the literature. However, the spectrum of abnormalities associated with CIC has been highly variable. Methods: We conducted a systematic review of the literature (until 1 June 2020) to assess CIC and disease severity during the early COVID-19 pandemic. Primary outcomes were pooled mean differences in platelet count, D-dimer level, prothrombin time, activated partial thromboplastin time (aPTT) and fibrinogen level between non-severe and severe patients, stratified by degree of hypoxaemia or those who died. The risk factors for CIC were analysed. Random-effects meta-analyses and meta-regression were performed using R version 3.6.1, and certainty of evidence was rated using the Grading of Recommendation, Assessment, Development, and Evaluation approach. Results: Of the included 5,243 adult COVID-19 patients, patients with severe COVID-19 had a significantly lower platelet count, and higher D-dimer level, prothrombin time and fibrinogen level than non-severe patients. Pooled mean differences in platelet count (-19.7×109/L, 95% confidence interval [CI] -31.7 to -7.6), D-dimer level (0.8μg/mL, 95% CI 0.5–1.1), prothrombin time (0.4 second, 95% CI 0.2–0.6) and fibrinogen level (0.6g/L, 95% CI 0.3–0.8) were significant between the groups. Platelet count and D-dimer level were significant predictors of disease severity on meta-regression analysis. Older men had higher risks of severe coagulopathic disease. Conclusion: Significant variability in CIC exists between non-severe and severe patients, with platelet count and D-dimer level correlating with disease severity. Routine monitoring of all coagulation parameters may help to assess CIC and decide on the appropriate management. Keywords: Coagulation parameters, coagulopathy, D-dimer, platelets

A Multimodality Machine Learning Approach to Differentiate Severe and Nonsevere COVID-19: Model Development and Validation

BACKGROUND

Effectively and efficiently diagnosing patients who have COVID-19 with the accurate clinical type of the disease is essential to achieve optimal outcomes for the patients as well as to reduce the risk of overloading the health care system. Currently, severe and nonsevere COVID-19 types are differentiated by only a few features, which do not comprehensively characterize the complicated pathological, physiological, and immunological responses to SARS-CoV-2 infection in the different disease types. In addition, these type-defining features may not be readily testable at the time of diagnosis.

OBJECTIVE

In this study, we aimed to use a machine learning approach to understand COVID-19 more comprehensively, accurately differentiate severe and nonsevere COVID-19 clinical types based on multiple medical features, and provide reliable predictions of the clinical type of the disease.

METHODS

For this study, we recruited 214 confirmed patients with nonsevere COVID-19 and 148 patients with severe COVID-19. The clinical characteristics (26 features) and laboratory test results (26 features) upon admission were acquired as two input modalities. Exploratory analyses demonstrated that these features differed substantially between two clinical types. Machine learning random forest models based on all the features in each modality as well as on the top 5 features in each modality combined were developed and validated to differentiate COVID-19 clinical types.

RESULTS

Using clinical and laboratory results independently as input, the random forest models achieved >90% and >95% predictive accuracy, respectively. The importance scores of the input features were further evaluated, and the top 5 features from each modality were identified (age, hypertension, cardiovascular disease, gender, and diabetes for the clinical features modality, and dimerized plasmin fragment D, high sensitivity troponin I, absolute neutrophil count, interleukin 6, and lactate dehydrogenase for the laboratory testing modality, in descending order). Using these top 10 multimodal features as the only input instead of all 52 features combined, the random forest model was able to achieve 97% predictive accuracy.

CONCLUSIONS

Our findings shed light on how the human body reacts to SARS-CoV-2 infection as a unit and provide insights on effectively evaluating the disease severity of patients with COVID-19 based on more common medical features when gold standard features are not available. We suggest that clinical information can be used as an initial screening tool for self-evaluation and triage, while laboratory test results should be applied when accuracy is the priority.

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2): a Systemic Infection

To date, seven identified coronaviruses (CoVs) have been found to infect humans; of these, three highly pathogenic variants have emerged in the 21st century. The newest member of this group, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was first detected at the end of 2019 in Hubei province, China. Since then, this novel coronavirus has spread worldwide, causing a pandemic; the respiratory disease caused by the virus is called coronavirus disease 2019 (COVID-19). The clinical presentation ranges from asymptomatic to mild respiratory tract infections and influenza-like illness to severe disease with accompanying lung injury, multiorgan failure, and death. Although the lungs are believed to be the site at which SARS-CoV-2 replicates, infected patients often report other symptoms, suggesting the involvement of the gastrointestinal tract, heart, cardiovascular system, kidneys, and other organs; therefore, the following question arises: is COVID-19 a respiratory or systemic disease? This review aims to summarize existing data on the replication of SARS-CoV-2 in different tissues in both patients and ex vivo models.

Prediction of COVID-19 severity using laboratory findings on admission: informative values, thresholds, ML model performance

BACKGROUND

Despite the necessity, there is no reliable biomarker to predict disease severity and prognosis of patients with COVID-19. The currently published prediction models are not fully applicable to clinical use.

OBJECTIVES

To identify predictive biomarkers of COVID-19 severity and to justify their threshold values for the stratification of the risk of deterioration that would require transferring to the intensive care unit (ICU).

METHODS

The study cohort (560 subjects) included all consecutive patients admitted to Dubai Mediclinic Parkview Hospital from February to May 2020 with COVID-19 confirmed by the PCR. The challenge of finding the cut-off thresholds was the unbalanced dataset (eg, the disproportion in the number of 72 patients admitted to ICU vs 488 non-severe cases). Therefore, we customised supervised machine learning (ML) algorithm in terms of threshold value used to predict worsening.

RESULTS

With the default thresholds returned by the ML estimator, the performance of the models was low. It was improved by setting the cut-off level to the 25th percentile for lymphocyte count and the 75th percentile for other features. The study justified the following threshold values of the laboratory tests done on admission: lymphocyte count <2.59×10⁹/L, and the upper levels for total bilirubin 11.9 μmol/L, alanine aminotransferase 43 U/L, aspartate aminotransferase 32 U/L, D-dimer 0.7 mg/L, activated partial thromboplastin time (aPTT) 39.9 s, creatine kinase 247 U/L, C reactive protein (CRP) 14.3 mg/L, lactate dehydrogenase 246 U/L, troponin 0.037 ng/mL, ferritin 498 ng/mL and fibrinogen 446 mg/dL.

CONCLUSION

The performance of the neural network trained with top valuable tests (aPTT, CRP and fibrinogen) is admissible (area under the curve (AUC) 0.86; 95% CI 0.486 to 0.884; p<0.001) and comparable with the model trained with all the tests (AUC 0.90; 95% CI 0.812 to 0.902; p<0.001). Free online tool at https://med-predict.com illustrates the study results.

Machining learning predicts the need for escalated care and mortality in COVID-19 patients from clinical variables

Objective: This study aimed to develop a machine learning algorithm to identify key clinical measures to triage patients more effectively to general admission versus intensive care unit (ICU) admission and to predict mortality in COVID-19 pandemic. Materials and methods: This retrospective study consisted of 1874 persons-under-investigation for COVID-19 between February 7, 2020, and May 27, 2020 at Stony Brook University Hospital, New York. Two primary outcomes were ICU admission and mortality compared to COVID-19 positive patients in general hospital admission. Demographic, vitals, symptoms, imaging findings, comorbidities, and laboratory tests at presentation were collected. Predictions of mortality and ICU admission were made using machine learning with 80% training and 20% testing. Performance was evaluated using receiver operating characteristic (ROC) area under the curve (AUC). Results: A total of 635 patients were included in the analysis (age 60±11, 40.2% female). The top 6 mortality predictors were age, procalcitonin, C-creative protein, lactate dehydrogenase, D-dimer and lymphocytes. The top 6 ICU admission predictors are procalcitonin, lactate dehydrogenase, C-creative protein, pulse oxygen saturation, temperature and ferritin. The best machine learning algorithms predicted mortality with 89% AUC and ICU admission with 79% AUC. Conclusion: This study identifies key independent clinical parameters that predict ICU admission and mortality associated with COVID-19 infection. The predictive model is practical, readily enhanced and retrained using additional data. This approach has immediate translation and may prove useful for frontline physicians in clinical decision making under time-sensitive and resource-constrained environment.

Role of vitamin D in treating COVID-19-associated coagulopathy: problems and perspectives

Aggressive inflammatory response leading to hypercoagulability has been found to be associated with disease severity in COVID-19 patients and portends bad treatment outcome. A state of acute disseminated intravascular coagulation (DIC), along with pulmonary embolism and/or deep vein thrombosis, has been observed in critically ill ICU patients. Autopsy reports of COVID-19 patients demonstrated microthrombi in lungs and in other organs, as well as marked inflammatory changes, characteristic clinicopathological features that exacerbate disease severity. Vitamin D supplementation was recommended by many clinicians across the globe to improve clinical symptoms of COVID-19 patients, mainly because of its immunomodulatory roles on immune cells. Furthermore, vitamin D and its associated molecules are also known to directly or indirectly regulate various thrombotic pathways. We propose that vitamin D supplementation not only attenuates the risk of Acute Respiratory Disease Syndrome (ARDS) but it also may have a role in reducing coagulation abnormalities in critically ill COVID-19 patients. The overarching goal of this review is to discuss the effects of vitamin D on coagulation pathways and other intertwined processes leading to thrombosis. Many clinical trials are currently investigating the efficacy of vitamin D supplementation in reducing the risk of COVID-19 infection. However, randomized placebo control clinical trials are also necessary to ascertain the effect of vitamin D supplementation on reducing the risk of coagulopathy in COVID-19 patients.

Vaccine formulations in clinical development for the prevention of severe acute respiratory syndrome coronavirus 2 infection

The COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to an unprecedented effort toward the development of an effective and safe vaccine. Aided by extensive research efforts into characterizing and developing countermeasures towards prior coronavirus epidemics, as well as recent developments of diverse vaccine platform technologies, hundreds of vaccine candidates using dozens of delivery vehicles and routes have been proposed and evaluated preclinically. A high demand coupled with massive effort from researchers has led to the advancement of at least 31 candidate vaccines in clinical trials, many using platforms that have never before been approved for use in humans. This review will address the approach and requirements for a successful vaccine against SARS-CoV-2, the background of the myriad of vaccine platforms currently in clinical trials for COVID-19 prevention, and a summary of the present results of those trials. It concludes with a perspective on formulation problems which remain to be addressed in COVID-19 vaccine development and antigens or adjuvants which may be worth further investigation.

Cytokine Storm and Mucus Hypersecretion in COVID-19: Review of Mechanisms

Mucus is an integral part of the respiratory physiology. It protects the respiratory tract by acting as a physical barrier against inhaled particles and microbes. Excessive inflammation in conditions such as COVID-19 can result in over-production of mucus which obstructs the airway. Build-up of mucus can also contribute to recurrent airway infection, causing further obstruction. This article summarizes the current understanding and knowledge of respiratory mucus production and proposes the role of cytokine storm in inducing sudden mucus hypersecretion in COVID-19. Based on these cascades, the active constituents that inhibit or activate several potential targets are outlined for further research. These may be explored for the discovery and design of drugs to combat cytokine storm and its ensuing complications.

Tocilizumab: From Rheumatic Diseases to COVID-19

Tocilizumab is a humanised interleukin-6 receptor-inhibiting monoclonal antibody that is currently approved for the treatment of rheumatoid arthritis and other immune-related conditions. Recently, tocilizumab has been investigated as a possible treatment for severe coronavirus-induced disease 2019 (COVID-19). Despite the lack of direct antiviral effects, tocilizumab could reduce the immune-induced organ damage caused by severe acute respiratory syndrome-coronavirus 2 (SARS-CoV2) infection. Until recently, most reports on tocilizumab for COVID-19 included a limited number of patients, preventing an overall evaluation of its efficacy and safety for this specific condition. Therefore, we reviewed the literature regarding the physiopathological rationale of tocilizumab for COVID-19 and its outcomes. We searched the MEDLINE database with the string "(SARS-CoV-2 OR coronavirus OR COVID-19 OR MERS- cov OR SARS-cov) AND (IL-6 OR interleukin 6 OR tocilizumab)". While the scientific rationale supporting tocilizumab for COVID-19 is solid, the evidence regarding the outcomes remains controversial. Available data and results from ongoing trials will provide useful information in the event of new COVID-19 outbreaks or future pandemics from different coronaviruses.

Peripheral ischemic limb necrosis (Acro-ischemia) associated with severe COVID-19 patients (COVID-19 limbs): A report of three cases

The association between severe coronavirus disease 2019 and hypercoagulable state was observed in many reports. This may be explained by the presence of hypoxia, severe systemic inflammatory response, immobilization due to intensive care unit (ICU) admission, and diffuse intravascular coagulation. We report three patients who were admitted to our respiratory ICU with acute severe respiratory distress syndrome (ARDS) requiring mechanical ventilation due severe acute respiratory syndrome coronavirus 2 infection, who developed severe limb ischemia during the course of the disease.

Obesity, malnutrition, and trace element deficiency in the coronavirus disease (COVID-19) pandemic: An overview

The world is currently facing the coronavirus disease (COVID-19) pandemic which places great pressure on health care systems and workers, often presents with severe clinical features, and sometimes requires admission into intensive care units. Derangements in nutritional status, both for obesity and malnutrition, are relevant for the clinical outcome in acute illness. Systemic inflammation, immune system impairment, sarcopenia, and preexisting associated conditions, such as respiratory, cardiovascular, and metabolic diseases related to obesity, could act as crucial factors linking nutritional status and the course and outcome of COVID-19. Nevertheless, vitamins and trace elements play an essential role in modulating immune response and inflammatory status. Overall, evaluation of the patient's nutritional status is not negligible for its implications on susceptibility, course, severity, and responsiveness to therapies, in order to perform a tailored nutritional intervention as an integral part of the treatment of patients with COVID-19. The aim of this study was to review the current data on the relevance of nutritional status, including trace elements and vitamin status, in influencing the course and outcome of the disease 3 mo after the World Health Organization's declaration of COVID-19 as a pandemic.

COVID-19 Pneumonia Resembling an Acute Exacerbation of Interstitial Pneumonia

An 84-year-old man was admitted with hypoxemia and ground-glass opacities with traction bronchiectasis in both lungs and mild fibrosis on computed tomography. We first suspected that he had acute exacerbation of interstitial pneumonia and initiated methylprednisolone pulse therapy. On day 4, he was diagnosed with coronavirus disease 2019 (COVID-19) pneumonia. Although the ground-glass opacities were improved with corticosteroid treatment alone, the hypoxemia persisted, and the plasma D-dimer level increased. Anticoagulant therapy was initiated, and the hypoxemia was improved. COVID-19 pneumonia may result in radiological findings similar to those of acute exacerbation of interstitial pneumonia, and corticosteroids and anticoagulant therapy may lead to favorable outcomes.

Malfunctioning temporary hemodialysis catheters in patients with novel coronavirus disease 2019

Objective

The hypercoagulability seen in patients with novel coronavirus disease 2019 (COVID-19) likely contributes to the high temporary hemodialysis catheter (THDC) malfunction rate. We aim to evaluate prophylactic measures and their association with THDC patency.

Methods

A retrospective chart review of our institutions COVID-19 positive patients who required placement of a THDC between February 1 to April 30, 2020, was performed. The association between heparin locking, increased dosing of venous thromboembolism (VTE) prophylaxis and systemic anticoagulation on THDC patency was assessed. Proportional hazards modeling was used to perform a survival analysis to estimate the likelihood and timing of THDC malfunction with the three different prophylactic measures. We also determined the mortality, rate of THDC malfunction and its association with d-dimer levels.

Results

A total of 48 patients with a mortality rate of 71% were identified. THDC malfunction occurred in 31.3% of patients. Thirty-seven patients (77.1%) received heparin locking, 22 (45.8%) received systemic anticoagulation, and 38 (79.1%) received VTE prophylaxis. Overall, the rate of THDC malfunction was lower at a trend level of significance, with heparin vs saline locking (24.3% vs 54.6%; P = .058). The likelihood of THDC malfunction in the heparin locked group is lower than all other groups (hazard ratio [HR], 0.07; 95% confidence interval [CI], 0.01-0.45]; P = .005). The rate of malfunction in patients with subcutaneous heparin (SQH) 7500 U three times daily is significantly lower than of the rate for patients receiving none (HR, 0.03; 95% CI, 0.001-0.74; P = .032). A trend level significant association was found for SQH 5000 U vs none (P = .417) and SQH 7500 vs 5000 U (P = .059). Systemic anticoagulation did not affect the THDC malfunction rate (P = .240). Higher d-dimer levels were related to greater mortality (HR, 3.28; 95% CI, 1.16-9.28; P = .025), but were not significantly associated with THDC malfunction (HR, 1.79; 95% CI, 0.42, 7.71; P = .434).

Conclusions

Locking THDCs with heparin is associated with a lower malfunction rate. Prospective randomized studies will be needed to confirm these findings to recommend locking THDC with heparin in patients with COVID-19. Increased VTE prophylaxis suggested a possible association with improved THDC patency, although the comparison lacked sufficient statistical power.

Human induced pluripotent stem cells as a tool for disease modeling and drug screening for COVID-19

The emergence of the new corona virus (SARS-CoV-2) and the resulting COVID-19 pandemic requires fast development of novel prevention and therapeutic strategies. These rely on understanding the biology of the virus and its interaction with the host, and on agnostic phenotypic screening for compounds that prevent viral infection. In vitro screenings of compounds are usually performed in human or animal-derived tumor or immortalized cell lines due to their ease of culturing. However, these platforms may not represent the tissues affected by the disease in vivo, and therefore better models are needed to validate and expedite drug development, especially in face of the COVID-19 pandemic. In this scenario, human induced pluripotent stem cells (hiPSCs) are a powerful research tool due to their ability to generate normal differentiated cell types relevant for the disease. Here we discuss the different ways hiPSCs can contribute to COVID-19 related research, including modeling the disease in vitro and serving as a platform for drug screening.