Histopathologic Findings in the Explant Lungs of a Patient With COVID-19 Treated With Bilateral Orthotopic Lung Transplant

Temperature impacts SARS-CoV-2 spike fusogenicity and evolution

SARS-CoV-2 infects both the upper and lower respiratory tracts, which are characterized by different temperatures (33°C and 37°C, respectively). In addition, fever is a common COVID-19 symptom. SARS-CoV-2 has been shown to replicate more efficiently at low temperatures, but the effect of temperature on different viral proteins remains poorly understood. Here, we investigate how temperature affects the SARS-CoV-2 spike function and evolution. We first observed that increasing temperature from 33°C to 37°C or 39°C increased spike-mediated cell-cell fusion. We then experimentally evolved a recombinant vesicular stomatitis virus expressing the SARS-CoV-2 spike at these different temperatures. We found that spike-mediated cell-cell fusion was maintained during evolution at 39°C but was lost in a high proportion of viruses that evolved at 33°C or 37°C. Consistently, sequencing of the spikes evolved at 33°C or 37°C revealed the accumulation of mutations around the furin cleavage site, a region that determines cell-cell fusion, whereas this did not occur in spikes evolved at 39°C. Finally, using site-directed mutagenesis, we found that disruption of the furin cleavage site had a temperature-dependent effect on spike-induced cell-cell fusion and viral fitness. Our results suggest that variations in body temperature may affect the activity and diversification of the SARS-CoV-2 spike.

IMPORTANCE

When it infects humans, SARS-CoV-2 is exposed to different temperatures (e.g., replication site and fever). Temperature has been shown to strongly impact SARS-CoV-2 replication, but how it affects the activity and evolution of the spike protein remains poorly understood. Here, we first show that high temperatures increase the SARS-CoV-2 spike fusogenicity. Then, we demonstrate that the evolution of the spike activity and variants depends on temperature. Finally, we show that the functional effect of specific spike mutations is temperature-dependent. Overall, our results suggest that temperature may be a factor influencing the activity and adaptation of the SARS-CoV-2 spike in vivo, which will help understanding viral tropism, pathogenesis, and evolution.

PDE5 inhibitors: breaking new grounds in the treatment of COVID-19

INTRODUCTION

Despite the ever-increasing occurrences of the coronavirus disease (COVID-19) cases around the world, very few medications have been validated in the clinical trials to combat COVID-19. Although several vaccines have been developed in the past quarter, the time elapsed between deployment and administration remains a major impediment.

CONTENT

Repurposing of pre-approved drugs, such as phosphodiesterase 5 (PDE5) inhibitors, could be a game-changer while lessening the burden on the current healthcare system. Repurposing and developing phosphodiesterase 5 (PDE5) inhibitors could extrapolate their utility to combat the SARS-CoV-2 infection, and potentially aid in the management of the symptoms associated with its newer variants such as BF.7, BQ.1, BQ.1.1, XBB.1.5, and XBB.1.16.

SUMMARY

Administration of PDE5 inhibitors via the oral and intravenous route demonstrates other potential off-label benefits, including anti-apoptotic, anti-inflammatory, antioxidant, and immunomodulatory effects, by intercepting several pathways. These effects can not only be of clinical importance in mild-to-moderate, but also moderate-to-severe SARS-CoV-2 infections. This article explores the various mechanisms by which PDE5 inhibitors alleviates the symptoms associated with COVID-19 as well as well as highlights recent studies and findings.

OUTLOOK

These benefits of PDE5 inhibitors make it a potential drug in the physicians' armamentarium in alleviating symptoms associated with SARS-CoV-2 infection. However, adequate clinical studies must be instituted to eliminate any untoward adverse events.

Nonspecific interstitial pneumonia pattern is a frequent finding in patients with post-acute COVID-19 syndrome treated with bilateral orthotopic lung transplantation: current best evidence

Patients with post-acute COVID-19 (PA-COVID) syndrome or long COVID-19 syndrome develop persistent symptoms and complications that last beyond 4 weeks of the initial infection. There is limited information regarding the pulmonary pathology in PA-COVID patients who require bilateral orthotopic lung transplantation (BOLT). Our experience with 40 lung explants from 20 PA-COVID patients who underwent BOLT is described. Clinicopathologic findings are correlated with best evidence from literature. The lung parenchyma showed bronchiectasis (n = 20) and severe interstitial fibrosis with areas resembling the nonspecific interstitial pneumonia (NSIP) pattern of fibrosis (n = 20), interstitial fibrosis not otherwise specified (n = 20), and fibrotic cysts (n = 9). None of the explants exhibited a usual interstitial pneumonia pattern of fibrosis. Other parenchymal changes included multinucleated giant cells (n = 17), hemosiderosis (n = 16), peribronchiolar metaplasia (n = 19), obliterative bronchiolitis (n = 6), and microscopic honeycombing (n = 5). Vascular abnormalities included thrombosis of a lobar artery (n = 1) and microscopic thrombi in small vessels (n = 7). Systematic literature review identified 7 articles reporting the presence in 12 patients of interstitial fibrosis showing the NSIP pattern (n = 3), organizing pneumonia/diffuse alveolar damage (n = 4) and not otherwise specified (n = 3) patterns. All but one of these studies also reported the presence of multinucleated giant cells and none of the studies reported the presence of severe vascular abnormalities. PA-COVID patients undergoing BOLT show a pattern of fibrosis that resembles a mixed cellular-fibrotic NSIP pattern and generally lack severe vascular complications. As the NSIP pattern of fibrosis is often associated with autoimmune diseases, additional studies are needed to understand the mechanism of disease and learn whether this information can be used for therapeutic purposes.

Crosstalk between Platelets and SARS-CoV-2: Implications in Thrombo-Inflammatory Complications in COVID-19

The SARS-CoV-2 virus, causing the devastating COVID-19 pandemic, has been reported to affect platelets and cause increased thrombotic events, hinting at the possible bidirectional interactions between platelets and the virus. In this review, we discuss the potential mechanisms underlying the increased thrombotic events as well as altered platelet count and activity in COVID-19. Inspired by existing knowledge on platelet-pathogen interactions, we propose several potential antiviral strategies that platelets might undertake to combat SARS-CoV-2, including their abilities to internalize the virus, release bioactive molecules to interfere with viral infection, and modulate the functions of immune cells. Moreover, we discuss current and potential platelet-targeted therapeutic strategies in controlling COVID-19, including antiplatelet drugs, anticoagulants, and inflammation-targeting treatments. These strategies have shown promise in clinical settings to alleviate the severity of thrombo-inflammatory complications and reduce the mortality rate among COVID-19 patients. In conclusion, an in-depth understanding of platelet-SARS-CoV-2 interactions may uncover novel mechanisms underlying severe COVID-19 complications and could provide new therapeutic avenues for managing this disease.

PDE5 inhibitors: breaking new grounds in the treatment of COVID-19

INTRODUCTION

Despite the ever-increasing occurrences of the coronavirus disease (COVID-19) cases around the world, very few medications have been validated in the clinical trials to combat COVID-19. Although several vaccines have been developed in the past quarter, the time elapsed between deployment and administration remains a major impediment.

CONTENT

Repurposing of pre-approved drugs, such as phosphodiesterase 5 (PDE5) inhibitors, could be a game-changer while lessening the burden on the current healthcare system. Repurposing and developing phosphodiesterase 5 (PDE5) inhibitors could extrapolate their utility to combat the SARS-CoV-2 infection, and potentially aid in the management of the symptoms associated with its newer variants such as BF.7, BQ.1, BQ.1.1, XBB.1.5, and XBB.1.16.

SUMMARY

Administration of PDE5 inhibitors via the oral and intravenous route demonstrates other potential off-label benefits, including anti-apoptotic, anti-inflammatory, antioxidant, and immunomodulatory effects, by intercepting several pathways. These effects can not only be of clinical importance in mild-to-moderate, but also moderate-to-severe SARS-CoV-2 infections. This article explores the various mechanisms by which PDE5 inhibitors alleviates the symptoms associated with COVID-19 as well as well as highlights recent studies and findings.

OUTLOOK

These benefits of PDE5 inhibitors make it a potential drug in the physicians' armamentarium in alleviating symptoms associated with SARS-CoV-2 infection. However, adequate clinical studies must be instituted to eliminate any untoward adverse events.

Ultrastructural study confirms the formation of single and heterotypic syncytial cells in bronchoalveolar fluids of COVID-19 patients

BACKGROUND

SARS-CoV-2 was reported to induce cell fusions to form multinuclear syncytia that might facilitate viral replication, dissemination, immune evasion, and inflammatory responses. In this study, we have reported the types of cells involved in syncytia formation at different stages of COVID-19 disease through electron microscopy.

METHODS

Bronchoalveolar fluids from the mild (n = 8, SpO2 > 95%, no hypoxia, within 2-8 days of infection), moderate (n = 8, SpO2 90% to ≤ 93% on room air, respiratory rate ≥ 24/min, breathlessness, within 9-16 days of infection), and severe (n = 8, SpO2 < 90%, respiratory rate > 30/min, external oxygen support, after 17th days of infection) COVID-19 patients were examined by PAP (cell type identification), immunofluorescence (for the level of viral infection), scanning (SEM), and transmission (TEM) electron microscopy to identify the syncytia.

RESULTS

Immunofluorescence studies (S protein-specific antibodies) from each syncytium indicate a very high infection level. We could not find any syncytial cells in mildly infected patients. However, identical (neutrophils or type 2 pneumocytes) and heterotypic (neutrophils-monocytes) plasma membrane initial fusion (indicating initiation of fusion) was observed under TEM in moderately infected patients. Fully matured large-size (20-100 μm) syncytial cells were found in severe acute respiratory distress syndrome (ARDS-like) patients of neutrophils, monocytes, and macrophage origin under SEM.

CONCLUSIONS

This ultrastructural study on the syncytial cells from COVID-19 patients sheds light on the disease's stages and types of cells involved in the syncytia formations. Syncytia formation was first induced in type II pneumocytes by homotypic fusion and later with haematopoetic cells (monocyte and neutrophils) by heterotypic fusion in the moderate stage (9-16 days) of the disease. Matured syncytia were reported in the late phase of the disease and formed large giant cells of 20 to 100 μm.

A diagnostic model for serious COVID-19 infection among older adults in Shanghai during the Omicron wave

Background

The Omicron variant is characterized by striking infectivity and antibody evasion. The analysis of Omicron variant BA.2 infection risk factors is limited among geriatric individuals and understanding these risk factors would promote improvement in the public health system and reduction in mortality. Therefore, our research investigated BA.2 infection risk factors for discriminating severe/critical from mild/moderate geriatric patients.

Methods

Baseline characteristics of enrolled geriatric patients (aged over 60 years) with Omicron infections were analyzed. A logistic regression analysis was conducted to evaluate factors correlated with severe/critical patients. A receiver operating characteristic (ROC) curve was constructed for predicting variables to discriminate mild/moderate patients from severe/critical patients.

Results

A total of 595 geriatric patients older than 60 years were enrolled in this study. Lymphocyte subset levels were significantly decreased, and white blood cells (WBCs) and D-dimer levels were significantly increased with disease progression from a mild/moderate state to a severe/critical state. Univariate and multivariate logistic regression analyses identified a panel of WBCs, CD4⁺ T cell, and D-dimer values that were correlated with good diagnostic accuracy for discriminating mild/moderate patients from severe/critical patients with an area under the curve of 0.962.

Conclusion

Some key baseline laboratory indicators change with disease development. A panel was identified for discriminating mild/moderate patients from severe/critical patients, suggesting that the panel could serve as a potential biomarker to enable physicians to provide timely medical services in clinical practice.

Ultrastructural Changes in Autopsy Tissues of COVID-19 Patients

INTRODUCTION

The COVID-19 pandemic resulted in substantial morbidity and mortality across the world. The prognosis was found to be poor in patients with co-morbidities such as diabetes, hypertension, interstitial lung disease, etc. Although biochemical studies were done in patient samples, no study has been reported from the Indian subcontinent about ultrastructural changes in the vital organs of COVID-19 patients. The present study was, therefore, conducted to understand the ultrastructural changes in the lung, liver, and brain of the deceased patients.

METHODS

The present study was conducted on samples obtained from reverse transcription-polymerase chain reaction (RT-PCR)-positive patients who were admitted to a tertiary care hospital in Western India. Core needle biopsies were done in eight fatal cases of COVID-19. The samples were taken from the lungs, liver, and brain and subjected to light microscopy, immunohistochemistry (IHC), and transmission electron microscopy (TEM). Clinical details and biochemical findings were also collected.  Results: The study participants included seven males and one female. The presenting complaints included fever, breathlessness, and cough. Light microscopy revealed diffuse alveolar damage in the lungs. Further, a positive expression of SARS-CoV-2 nucleocapsid protein was observed in the pulmonary parenchyma of five patients. Also, the TEM microphotograph showed viral particles of size up to 80nm localized in alveolar epithelial cells. However, no viral particles were found in liver or brain samples. In the liver, macrovesicular steatosis and centrizonal congestion with loss of hepatocytes were observed in light microscopy.

CONCLUSION

 This is the first study in the Indian population showing the in-situ presence of viral particles in core biopsies from fatal cases of COVID-19. As evident from the results, histology and ultrastructural changes in the lung correlated with the presence of viral particles. The study revealed a positive correlation between the damage in the lungs and the presence of viral particles.

D-dimer levels and characteristics of lymphocyte subsets, cytokine profiles in peripheral blood of patients with severe COVID-19: A systematic review and meta-analysis

Purpose

A series of complications caused by severe COVID-19 can significantly affect short-term results. Therefore, early diagnosis is essential for critically COVID-19 patients. we aimed to investigate the correlation among D-dimer levels, lymphocyte subsets, cytokines, and disease severity in COVID-19 patients.

Methods

Systematic review and meta- analysis of PubMed, Scopus, Web of Science, Cochrane Central Register of Controlled Trials, Embase, clinical trials, and China National Knowledge Infrastructure (CNKI) until 1 August 2022. We considered case-control, and cohort studies that compared laboratory parameters between patients with severe or non-serious diseases or between survivors and non-survivors. Pooled data was assessed by use of a random-effects model and used I 2 to test heterogeneity. We assessed the risk of bias using the Newcastle- Ottawa Scale.

Results

Of the 5,561 identified studies, 32 were eligible and included in our analysis (N = 3,337 participants). Random-effect results indicated that patients with COVID-19 in severe group had higher levels for D-dimer (WMD = 1.217 mg/L, 95%CI=[0.788, 1.646], P < 0.001), neutrophil-to-lymphocyte ratio (NLR) (WMD = 6.939, 95%CI = [4.581, 9.297], P < 0.001), IL-2 (WMD = 0.371 pg/ml, 95%CI = [-0.190, 0.932], P = 0.004), IL-4 (WMD = 0.139 pg/ml, 95%CI = [0.060, 0.219], P = 0.717), IL-6 (WMD = 44.251 pg/ml, 95%CI = [27.010, 61.493], P < 0.001), IL-10 (WMD = 3.718 pg/ml, 95%CI = [2.648, 4.788], P < 0.001) as well as lower levels of lymphocytes (WMD = -0.468( × 109/L), 95%CI = [-0.543, -0.394], P < 0.001), T cells (WMD = -446.746(/μL), 95%CI = [-619.607, -273.885], P < 0.001), B cells (WMD = -60.616(/μL), 95%CI = [-96.452, -24.780], P < 0.001), NK cells (WMD = -68.297(/μL), 95%CI = [-90.600, -45.994], P < 0.001), CD3+T cells (WMD = -487.870(/μL), 95%CI = [-627.248, -348.492], P < 0.001), CD4+T cells (WMD = -290.134(/μL), 95%CI = [-370.834, -209.435], P < 0.001), CD8+T cells (WMD = -188.781(/μL), 95%CI = [-227.806, -149.757], P < 0.001).

Conclusions

There is a correlation among higher levels of D-dimer, cytokines, lower levels of lymphocyte subsets, and disease severity in COVID-19 patients. These effective biomarkers may help clinicians to evaluate the severity and prognosis of COVID-19. This study is registered with PROSPERO, number CRD42020196659.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=196659; PROSPERO registration number: CRD42020196659.

Development and validation of chest CT-based imaging biomarkers for early stage COVID-19 screening

Coronavirus Disease 2019 (COVID-19) is currently a global pandemic, and early screening is one of the key factors for COVID-19 control and treatment. Here, we developed and validated chest CT-based imaging biomarkers for COVID-19 patient screening from two independent hospitals with 419 patients. We identified the vasculature-like signals from CT images and found that, compared to healthy and community acquired pneumonia (CAP) patients, COVID-19 patients display a significantly higher abundance of these signals. Furthermore, unsupervised feature learning led to the discovery of clinical-relevant imaging biomarkers from the vasculature-like signals for accurate and sensitive COVID-19 screening that have been double-blindly validated in an independent hospital (sensitivity: 0.941, specificity: 0.920, AUC: 0.971, accuracy 0.931, F1 score: 0.929). Our findings could open a new avenue to assist screening of COVID-19 patients.

Imaging Techniques: Essential Tools for the Study of SARS-CoV-2 Infection

The world has seen the emergence of a new virus in 2019, SARS-CoV-2, causing the COVID-19 pandemic and millions of deaths worldwide. Microscopy can be much more informative than conventional detection methods such as RT-PCR. This review aims to present the up-to-date microscopy observations in patients, the in vitro studies of the virus and viral proteins and their interaction with their host, discuss the microscopy techniques for detection and study of SARS-CoV-2, and summarize the reagents used for SARS-CoV-2 detection. From basic fluorescence microscopy to high resolution techniques and combined technologies, this article shows the power and the potential of microscopy techniques, especially in the field of virology.

Interstitial Pulmonary Fibrosis and Extensive Dendriform Ossification with Persistent Viral Load: A Rare Presentation of Post-COVID-19 Condition in Need of Lung Transplantation

The incidence, presentation, and predisposing factors of post-acute sequelae of COVID-19 (PASC) are currently poorly understood. Lung explants may provide a rare insight into terminal SARS-CoV-2-associated lung damage and its pathophysiology. A 62-year-old man presented with progressively worsening respiratory symptoms after recovering from mild COVID-19 3 months earlier. No underlying pulmonary comorbidities were reported. A chest CT revealed bilateral extensive ground-glass and reticular opacities, suspicious of pulmonary fibrosis. Despite initial high-dose glucocorticoid therapy, the interstitial lung disease progressed, and after exhausting all viable therapeutic options, bilateral lung transplantation was successfully conducted. Histological analysis revealed extensive end-stage interstitial fibrosis with diffuse dendriform ossification and bronchiolar and transitional cell metaplasia. Signs of interstitial remodeling such as an increased interstitial collagen deposition, a pathological accumulation of CD163+/CD206+ M2-polarized macrophages with an increased expression of phosphorylated ERK, and an increased density of CD105+ newly formed capillaries were observed. qRT-PCR and immunohistochemistry for SARS-CoV-2 N-protein in the endothelium of medium-sized vessels confirmed a persistence of SARS-CoV-2. Our findings highlight a highly unusual presentation of SARS-CoV-2-associated lung fibrosis, implying that incomplete viral clearance in the vascular compartment may play a vital pathophysiological role in the development of PASC.

Differential effects of macrophage subtypes on SARS-CoV-2 infection in a human pluripotent stem cell-derived model

Dysfunctional immune responses contribute critically to the progression of Coronavirus Disease-2019 (COVID-19), with macrophages as one of the main cell types involved. It is urgent to understand the interactions among permissive cells, macrophages, and the SARS-CoV-2 virus, thereby offering important insights into effective therapeutic strategies. Here, we establish a lung and macrophage co-culture system derived from human pluripotent stem cells (hPSCs), modeling the host-pathogen interaction in SARS-CoV-2 infection. We find that both classically polarized macrophages (M1) and alternatively polarized macrophages (M2) have inhibitory effects on SARS-CoV-2 infection. However, M1 and non-activated (M0) macrophages, but not M2 macrophages, significantly up-regulate inflammatory factors upon viral infection. Moreover, M1 macrophages suppress the growth and enhance apoptosis of lung cells. Inhibition of viral entry using an ACE2 blocking antibody substantially enhances the activity of M2 macrophages. Our studies indicate differential immune response patterns in distinct macrophage phenotypes, which could lead to a range of COVID-19 disease severity.

D-dimer and CoV-2 spike-immune complexes contribute to the production of PGE2 and proinflammatory cytokines in monocytes

An overreactive inflammatory response and coagulopathy are observed in patients with severe form of COVID-19. Since increased levels of D-dimer (DD) are associated with coagulopathy in COVID-19, we explored whether DD contributes to the aberrant cytokine responses. Here we show that treatment of healthy human monocytes with DD induced a dose dependent increase in production of pyrogenic mediator, Prostaglandin E2 (PGE2) and inflammatory cytokines, IL-6 and IL-8. The DD-induced PGE2 and inflammatory cytokines were enhanced significantly by co-treatment with immune complexes (IC) of SARS CoV-2 recombinant S protein or of pseudovirus containing SARS CoV-2 S protein (PVCoV-2) coated with spike-specific chimeric monoclonal antibody (MAb) containing mouse variable and human Fc regions. The production of PGE2 and cytokines in monocytes activated with DD and ICs was sensitive to the inhibitors of β2 integrin and FcγRIIa, and to the inhibitors of calcium signaling, Mitogen-Activated Protein Kinase (MAPK) pathway, and tyrosine-protein kinase. Importantly, strong increase in PGE2 and in IL-6/IL-8/IL-1β cytokines was observed in monocytes activated with DD in the presence of IC of PVCoV-2 coated with plasma from hospitalized COVID-19 patients but not from healthy donors. The IC of PVCoV-2 with convalescent plasma induced much lower levels of PGE2 and cytokines compared with plasma from hospitalized COVID-19 patients. PGE2 and IL-6/IL-8 cytokines produced in monocytes activated with plasma-containing IC, correlated well with the levels of spike binding antibodies and not with neutralizing antibody titers. Our study suggests that a combination of high levels of DD and high titers of spike-binding antibodies that can form IC with SARS CoV-2 viral particles might accelerate the inflammatory status of lung infiltrating monocytes leading to increased lung pathology in patients with severe form of COVID-19.

Clinico-radiological-pathological profile and outcomes of Lung transplantation in post covid-19 phenotype: A single centre experience

Background

Lung transplantation (LTx) has come as hope for select patients with post-COVID acute respiratory distress syndrome (ARDS). It has a different phenotype with unique challenges. We aimed to bring out our experience with and outcomes of LTx for post-COVID ARDS.

Methods

This study is retrospective case series from a single center in India. All the patients with post-COVID end stage lung disease (ESLD) who underwent bilateral LTx between 1st May 2020 and 30th August 2021 were included. LTx was performed following no improvement with optimal medical management with adequate time provided for recovery. Information relating to demographics, comorbidities, pretransplant status, perioperative parameters, gross and histopathological findings of explanted lungs, posttransplant morbidity, and mortality were analyzed.

Results

This study included 23 patients. The median age of the patients in this study was 42 years and 20 participants were men (87%). The mean duration of intensive care unit stay was 15.83 ± 6.61 days. Mortality was observed among 8 participants (34.78%). Mean survival time was 34.54 weeks. Among the 8 patients who expired, the cause of death was sepsis for 6 patients (75.0%), neurologic cerebrovascular accident for 1 patient (12.5%), and cytomegalovirus for 1 patient (12.5%). All the deaths were reported in primary graft dysfunction grade 2 & 3 category. No rejections were observed on first and third month surveillance biopsies.

Conclusions

LTx is the definitive option for survival in select patients with severe post–COVID-19–associated ESLD. This study brings out various challenges involved in such phenotypes and also observations in postoperative recovery.

Machine Learning to Calculate Heparin Dose in COVID-19 Patients with Active Cancer

To realize a machine learning (ML) model to estimate the dose of low molecular weight heparin to be administered, preventing thromboembolism events in COVID-19 patients with active cancer. Methods: We used a dataset comprising 131 patients with active cancer and COVID-19. We considered five ML models: logistic regression, decision tree, random forest, support vector machine and Gaussian naive Bayes. We decided to implement the logistic regression model for our study. A model with 19 variables was analyzed. Data were randomly split into training (70%) and testing (30%) sets. Model performance was assessed by confusion matrix metrics on the testing data for each model as positive predictive value, sensitivity and F1-score. Results: We showed that the five selected models outperformed classical statistical methods of predictive validity and logistic regression was the most effective, being able to classify with an accuracy of 81%. The most relevant result was finding a patient-proof where python function was able to obtain the exact dose of low weight molecular heparin to be administered and thereby to prevent the occurrence of VTE. Conclusions: The world of machine learning and artificial intelligence is constantly developing. The identification of a specific LMWH dose for preventing VTE in very high-risk populations, such as the COVID-19 and active cancer population, might improve with the use of new training ML-based algorithms. Larger studies are needed to confirm our exploratory results.

Altered fibrin clot structure and dysregulated fibrinolysis contribute to thrombosis risk in severe COVID-19

Elevated fibrinogen, in conjunction with accelerated formation of FXIIa, may promote compact fibrin clot architecture in COVID-19.

A dense fibrin network and dysregulated fibrinolysis collectively contribute to a high incidence of thrombotic events in COVID-19.

The high incidence of thrombotic events suggests a possible role of the contact system pathway in COVID-19 pathology. In this study, we determined the altered levels of factor XII (FXII) and its activation products in critically ill patients with COVID-19 in comparison with patients with severe acute respiratory distress syndrome related to the influenza virus (acute respiratory distress syndrome [ARDS]-influenza). Compatible with those data, we found rapid consumption of FXII in COVID-19 but not in ARDS-influenza plasma. Interestingly, the lag phase in fibrin formation, triggered by the FXII activator kaolin, was not prolonged in COVID-19, as opposed to that in ARDS-influenza. Confocal and electron microscopy showed that increased FXII activation rate, in conjunction with elevated fibrinogen levels, triggered formation of fibrinolysis-resistant, compact clots with thin fibers and small pores in COVID-19. Accordingly, clot lysis was markedly impaired in COVID-19 as opposed to that in ARDS-influenza. Dysregulated fibrinolytic system, as evidenced by elevated levels of thrombin-activatable fibrinolysis inhibitor, tissue-plasminogen activator, and plasminogen activator inhibitor-1 in COVID-19 potentiated this effect. Analysis of lung tissue sections revealed widespread extra- and intravascular compact fibrin deposits in patients with COVID-19. A compact fibrin network structure and dysregulated fibrinolysis may collectively contribute to a high incidence of thrombotic events in COVID-19.

Impaired Dendritic Cell Homing in COVID-19

The high mortality of COVID-19 is mostly attributed to acute respiratory distress syndrome (ARDS), whose histopathological correlate is diffuse alveolar damage (DAD). Furthermore, severe COVID-19 is often accompanied by a cytokine storm and a disrupted response of the adaptive immune system. Studies aiming to depict this dysregulation have mostly investigated the peripheral cell count as well as the functionality of immune cells. We investigated the impact of SARS-CoV-2 on antigen-presenting cells using multiplexed immunofluorescence. Similar to MERS-CoV and SARS-CoV, SARS-CoV-2 appears to be impairing the maturation of dendritic cells (DCs). DC maturation involves a switch in surface antigen expression, which enables the cells' homing to lymph nodes and the subsequent activation of T-cells. As quantitative descriptions of the local inflammatory infiltrate are still scarce, we compared the cell population of professional antigen-presenting cells (APC) in the lungs of COVID-19 autopsy cases in different stages of DAD. We found an increased count of myeloid dendritic cells (mDCs) in later stages. Interestingly, mDCs also showed no significant upregulation of maturation markers in DAD-specimens with high viral load. Accumulation of immature mDCs, which are unable to home to lymph nodes, ultimately results in an inadequate T-cell response.

Successful Lung Transplantation for Severe Post COVID-19 Pulmonary Fibrosis

Lung transplantation has been well described for patients with coronavirus disease 2019 (COVID-19) in the acute setting, but less so for the resulting pulmonary sequelae. This report describes a case of lung transplantation for post–COVID-19 pulmonary fibrosis. A 52-year-old woman contracted COVID-19 in July 2020 and mounted a partial recovery, but she went on to have declining function over the ensuing 3 months, with development of fibrocystic lung changes. She underwent bilateral lung transplantation and recovered rapidly, was discharged home on postoperative day 14, and has done well in follow-up. This case report demonstrates that lung transplantation is an acceptable therapy for post–COVID-19 pulmonary fibrosis.

COVID-19-Related Pulmonary Embolism: Incidence, Characteristics, and Risk Factors

INTRODUCTION

 The 2020 world pandemic caused by the novel coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was initially reported in December 2019 in Wuhan, China, which has since then spread globally. Several studies on patients with coronavirus disease 2019 (COVID-19) describe a high risk of pulmonary embolism (PE). The majority of PEs in patients with COVID-19 were in the segmental arteries. Therefore, this study aims to determine the rate of PE in patients with COVID-19 at King Abdulaziz Medical City in Jeddah, Saudi Arabia. Other risk factors of PE were taken into consideration.

PATIENTS AND METHODS

 This study is a single-center, retrospective, cross-sectional study that used a non-probability consecutive sampling technique to select the patients. The local institutional review boards approved the study protocol. Overall, 91 consecutive patients who were older than 18 years of age and who had a computerized tomography (CT) pulmonary angiography were included in this study.

RESULTS

 Ninety-one patients met the inclusion and exclusion criteria, of whom 46 (50.5%) were females and 45 (49.5%) were males. The study population's age ranged from 19 to 87 with a mean age of 59 ± 15 years. PE was documented in 11 patients (12.1%). Seventy-three patients underwent CT scan angiography during COVID-19 manifestation, while 18 patients had it after recovering from COVID-19. Out of the 11 patients with PE, eight were diagnosed with PE while being COVID-19 positive, and three were diagnosed with PE after recovery from COVID-19.

CONCLUSION

Several potential clinical implications can be concluded for this study. Firstly, effective evaluation of the risk of PE in patients with COVID-19 is based on clinical findings such as chest pain, hemoptysis, lower limb edema, and, most significantly, shortness of breath. Secondly, measuring D-dimer remains an effective test for ruling out PE in patients with COVID-19 as in patients without COVID-19.

The Mechanism and Consequences of SARS-CoV-2 Spike-Mediated Fusion and Syncytia Formation

Syncytia are formed when individual cells fuse. SARS-CoV-2 induces syncytia when the viral spike (S) protein on the surface of an infected cell interacts with receptors on neighboring cells. Syncytia may potentially contribute to pathology by facilitating viral dissemination, cytopathicity, immune evasion, and inflammatory response. SARS-CoV-2 variants of concern possess several mutations within the S protein that enhance receptor interaction, fusogenicity and antibody binding. In this review, we discuss the molecular determinants of S mediated fusion and the antiviral innate immunity components that counteract syncytia formation. Several interferon-stimulated genes, including IFITMs and LY6E act as barriers to S protein-mediated fusion by altering the composition or biophysical properties of the target membrane. We also summarize the effect that the mutations associated with the variants of concern have on S protein fusogenicity. Altogether, this review contextualizes the current understanding of Spike fusogenicity and the role of syncytia during SARS-CoV-2 infection and pathology.

The diagnostic value of neutrophil to lymphocyte ratio in determining the severity of COVID-19

Background: Changes in hematological parameters play a role in the pathogenesis of coronavirus disease 2019 (COVID-19). We aimed to investigate the significance of neutrophil-lymphocyte ratio (NLR) and hematologic parameters in determining the severity of COVID-19. Methods: This retrospective cross-sectional study was conducted on adult patients diagnosed with COVID-19 in two pandemic hospitals between 01, April, and 01, July 2020. Using the COVID-19 diagnostic criteria of the world health organization (WHO), the patients were divided into two groups as severe and non-severe. Demographic and clinical characteristics, white blood cell (WBC), neutrophil, lymphocyte and platelet counts, and NLR of all patients were examined at the first admission. Multivariate analyzes were performed to determine the independent predictive data and ROC analysis to test the diagnostic accuracy of the hematological parameters. Results: Of the 381 patients included in the study, 42 (11%) had severe COVID-19 infection. While the mean NLR was 7.61±7.48 in patients with severe COVID-19, the mean NLR of non-severe patients was 2.97±2.37 (95% CI: 2.294 to 6.984, p<0.001). Long duration of hospital stay, elevated NLR ratio, female gender were predictive variables of severe COVID-19 cases (OR =0.833, 95% CI: 0.744 to 0.934, p=0.002; OR=0.195, 95% CI: 0.057 to 0.6731, p=0.010; OR=0.664, 95% CI: 0.501 to 0.881, p=0.005, respectively). In ROC analysis, NLR ratio had 2.625 optimum cut-off value, 60% specificity (95% CI: 54.7 to 65.4), 86% sensitivity (95% CI: 71.5 to 94.6), positive likelihood ratio (PLR) of 4.2 (95% CI: 2.0 to 8.9) and negative likelihood ratio (NLR) of 0.46 (95% CI: 0.4 to 0.6) for severe COVID-19 cases. Conclusion: The results of this study revealed that there might be a relationship between elevated NLR and severity in COVID-19 cases. IMC J Med Sci 2022; 16(1): 001 *Correspondence: Dr. Umut Gulacti, Adiyaman University Training and Research Hospital, Emergency Medicine, Adiyaman, Turkey. E-mail: umutgulacti@gmail.com

Important scoring systems for assessing the severity of COVID-19 based on COVID-19-related deaths in Wuhan, China

Background

This study aimed to investigate the clinical characteristics of 21 deaths and evaluate potential factors affecting disease severity and mortality risk in patients with coronavirus disease (COVID-19).

Methods

This retrospective analysis assessed clinical data of 21 patients who died owing to COVID-19. Disease severity and mortality risk were assessed using Acute Physiology and Chronic Health Evaluation II (APACHE II); Sepsis-related Organ Failure Assessment (SOFA); multilobular infiltration, hypo-lymphocytosis, bacterial coinfection, smoking history, hypertension and age (MuLBSTA); and pneumonia severity index (PSI) scores.

Results

The mean age of the patients was 66 ± 14 years and 15 (71.4%) patients were men. Sixteen (76.2%) patients had chronic medical illnesses. Twelve (57.1%) patients were overweight. Decreased lymphocyte proportions were observed in 17 (81.0%) patients on admission. Elevated D-dimer levels were observed in 11 (52.4%) patients, and the levels significantly increased when pneumonia deteriorated. The initial APACHE II and SOFA scores demonstrated that 18 (85.7%) and 13 (61.9%) patients, respectively, were in the middle-risk level. MuLBSTA and PSI scores after admission were associated with higher risks of mortality in 13 (61.9%) patients. Most patients developed organ failure and subsequently died.

Conclusions

Older, overweight, male patients with a history of chronic illnesses and continuously decreased lymphocyte proportions and increased D-dimer levels might have higher risks of death owing to COVID-19. The combination of general scoring (SOFA) and pneumonia-specific scoring (MuLBSTA and PSI) systems after admission might be sensitive in assessing the mortality risk of patients with COVID-19 who are in critical condition.

Utilization of Airway Pressure Release Ventilation as a Rescue Strategy in COVID-19 Patients: A Retrospective Analysis

Background:

Airway Pressure Release Ventilation (APRV) is a pressure controlled intermittent mandatory mode of ventilation characterized by prolonged inspiratory time and high mean airway pressure. Several studies have demonstrated that APRV can improve oxygenation and lung recruitment in patients with Acute Respiratory Distress Syndrome (ARDS). Although most patients with COVID-19 meet the Berlin criteria for ARDS, hypoxic respiratory failure due to COVID-19 may differ from traditional ARDS as patients often present with severe, refractory hypoxemia and significant variation in respiratory system compliance. To date, no studies investigating APRV in this patient population have been published. The aim of this study was to evaluate the effectiveness of APRV as a rescue mode of ventilation in critically ill patients diagnosed with COVID-19 and refractory hypoxemia.

Methods:

We conducted a retrospective analysis of patients admitted with COVID-19 requiring invasive mechanical ventilation who were treated with a trial of APRV for refractory hypoxemia. PaO₂/FIO₂ (P/F ratio), ventilatory ratio and ventilation outputs before and during APRV were compared.

Results:

APRV significantly improved the P/F ratio and decreased FIO₂ requirements. PaCO₂ and ventilatory ratio were also improved. There was an increase in tidal volume per predicted body weight during APRV and a decrease in total minute ventilation. On multivariate analysis, higher inspiratory to expiratory ratio (I: E) and airway pressure were associated with greater improvement in P/F ratio.

Conclusions:

APRV may improve oxygenation, alveolar ventilation and CO₂ clearance in patients with COVID-19 and refractory hypoxemia. These effects are more pronounced with higher airway pressure and inspiratory time.

Lung Transplantation for Severe Post-coronavirus Disease 2019 Respiratory Failure

BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic has resulted in >72 million cases and 1.6 million deaths. End-stage lung disease from COVID-19 is a new and growing entity that may benefit from lung transplant; however, there are limited data on the patient selection, perioperative management, and expected outcomes of transplantation for this indication.

METHODS

A systematic review of the literature was performed with searches of MEDLINE and Web of Science databases as well as the gray literature. All manuscripts, editorials, commentaries, and gray literature reports of lung transplantation for COVID-related respiratory failure were included. A case from the University of Virginia is described and included in the review.

RESULTS

A total of 27 studies were included: 11 manuscripts, 5 commentaries, and 11 gray literature reports. The total number of transplantations for COVID-related lung disease was 21. The mean age was 55±12 years, 16 (76%) were male individuals, and the acuity was high, with 85% on extracorporeal membrane oxygenation preoperatively. There was a 95% early survival rate, with 1 additional late death. There is growing histopathologic evidence for permanent structural damage with no replicating virus at the time of transplantation.

CONCLUSIONS

Bilateral lung transplantation is an effective treatment option with reasonable short-term outcomes for patients with end-stage lung failure secondary to COVID-19. However, specific considerations in this new population require a multidisciplinary approach. As we move into the second wave of the COVID-19 global pandemic, lung transplantation will likely have a growing role in management of these complex patients.

Selection Criteria for Lung Transplantation: Controversies and New Developments

Lung transplantation is an accepted therapeutic option for end-stage lung diseases. The imbalance between limited availability and vast need of donor organs necessitates careful selection of recipient candidates, ensuring the best possible utilization of the scarce resource of organs. Nonetheless, possible lung transplant candidates who could experience a meaningful improvement in survival and quality of life should not be excluded solely based on the complexity of their case. In this review, controversial issues or difficult limitations for lung transplantation, and new developments in recipient selection criteria, are discussed, which may help broaden recipient eligibility for lung transplantation without compromising long-term outcomes.

Case Report: COVID-19 Pneumonia Following Left Pneumonectomy for Lung Cancer Complicated by Empyema and Bronchopleural Fistula

Background: Venous and arterial thromboembolism is commonly reported in critically ill COVID-19 patients, although there are still no definitive statistical data regarding its incidence.

Case presentation: we report a case of a patient who fell ill with Covid during hospitalization for a pneumonectomy complicated by empyema and bronchopleural fistula. The patient, despite being cured of COVID, died after 14 days for pulmonary thromboembolism.

Conclusion: Our case strengthens the suggestion of adequate thromboprophylaxis in all hospitalized COVID patients and of increasing prophylaxis in critically ill patients even in the absence of randomized studies

Different Anticoagulant Regimens, Mortality, and Bleeding in Hospitalized Patients with COVID-19: A Systematic Review and an Updated Meta-Analysis

We conducted a systematic review and a meta-analysis to assess the association of anticoagulants and their dosage with in-hospital all-cause mortality in COVID-19 patients. Articles were retrieved until January 8, 2021, by searching in seven electronic databases. The main outcome was all-cause mortality occurred during hospitalization. Data were combined using the general variance-based method on the effect estimate for each study. Separate meta-analyses according to type of COVID-19 patients (hospitalized or intensive care unit [ICU] patients), anticoagulants (mainly heparin), and regimens (therapeutic or prophylactic) were conducted. A total of 29 articles were selected, but 23 retrospective studies were eligible for quantitative meta-analyses. No clinical trial was retrieved. The majority of studies were of good quality; however, 34% did not distinguish heparin from other anticoagulants. Meta-analysis on 25,719 hospitalized COVID-19 patients showed that anticoagulant use was associated with 50% reduced in-hospital mortality risk (pooled risk ratio [RR]: 0.50, 95% confidence interval [CI]: 0.40-0.62; I ²: 87%). Both anticoagulant regimens (therapeutic and prophylactic) reduced in-hospital all-cause mortality, compared with no anticoagulation. Particularly in ICU patients, the anticoagulant therapeutic regimen was associated with a reduced in-hospital mortality risk (RR: 0.30, 95% CI: 0.15-0.60; I ²: 58%) compared with the prophylactic one. However, the former was also associated with a higher risk of bleeding (RR: 2.53, 95% CI: 1.60-4.00; I ²: 65%). Anticoagulant use, mainly heparin, reduced all-cause mortality in COVID-19 patients during hospitalization. Due to the higher risk of bleeding at therapeutic doses, the use of prophylactic dosages of anticoagulant is probably to be preferred in noncritically ill COVID-19 patients.

Pathological findings and morphologic correlation of the lungs of autopsied patients with SARS-CoV-2 infection in the Brazilian Amazon using transmission electron microscopy

INTRODUCTION:

Electron microscopy (EM) is a rapid and effective tool that can be used to create images of a whole spectrum of virus-host interactions and, as such, has long been used in the discovery and description of viral mechanisms.

METHODS:

Electron microscopy was used to evaluate the pulmonary pathologies of postmortem lung sections from three patients who died from infection with SARS-associated coronavirus 2 (SARS-CoV-2), a new member of the Coronaviridae family.

RESULTS:

Diffuse alveolar damage (DAD) was predominant in all three patients. The early exudative stage was characterized principally by edema and extravasation of red blood cells into the alveolar space with injury to the alveolar epithelial cells; this was followed by detachment, apoptosis, and necrosis of type I and II pneumocytes. The capillaries exhibited congestion, exposure of the basement membrane from denuded endothelial cells, platelet adhesion, fibrin thrombi, and rupture of the capillary walls. The proliferative stage was characterized by pronounced proliferation of type II alveolar pneumocytes and multinucleated giant cells. The cytopathic effect of SARS-CoV-2 was observed both in degenerated type II pneumocytes and freely circulating in the alveoli, with components from virions, macrophages, lymphocytes, and cellular debris.

CONCLUSIONS:

Viral particles consistent with the characteristics of SARS-CoV-2 were observed mainly in degenerated pneumocytes, in the endothelium, or freely circulating in the alveoli. In the final stage of illness, the alveolar spaces were replaced by fibrosis.

Optimizing Management to Reduce the Mortality of COVID-19: Experience From a Designated Hospital for Severely and Critically Ill Patients in China

Background: The coronavirus disease 2019 (COVID-19) has swept through the world at a tremendous speed, and there is still limited data available on the treatment for COVID-19. The mortality of severely and critically ill COVID-19 patients in the Optical Valley Branch of Tongji Hospital was low. We aimed to analyze the available treatment strategies to reduce mortality. Methods: In this retrospective, single-center study, we included 1,106 COVID-19 patients admitted to the Optical Valley Branch of Tongji Hospital from February 9 to March 9, 2020. Cases were analyzed for demographic and clinical features, laboratory data, and treatment methods. Outcomes were followed up until March 29, 2020. Results: Inflammation-related indices (hs-CRP, ESR, serum ferritin, and procalcitonin) were significantly higher in severe and critically ill patients than those in moderate patients. The levels of cytokines, including IL-6, IL2R, IL-8, and TNF-α, were also higher in the critical patients. Incidence of acute respiratory distress syndrome (ARDS) in the severely and critically ill group was 23.0% (99/431). Sixty-one patients underwent invasive mechanical ventilation. The correlation between SpO2/FiO2 and PaO2/FiO2 was confirmed, and the cut-off value of SpO2/FiO2 related to survival was 134.43. The mortality of patients with low SpO2/FiO2 (<134.43) at intubation was higher than that of patients with high SpO2/FiO2 (>134.43) (72.7 vs. 33.3%). Among critical patients, the application rates of glucocorticoid therapy, continuous renal replacement therapy (CRRT), and anticoagulation treatment reached 55.2% (238/431), 7.2% (31/431), and 37.1% (160/431), respectively. Among the intubated patients, the application rates of glucocorticoid therapy, CRRT, and anticoagulation treatment were respectively 77.0% (47/61), 54.1% (33/61), and 98.4% (60/61). Conclusion: No vaccines or specific antiviral drugs for COVID-19 have been shown to be sufficiently safe and effective to date. Comprehensive treatment including ventilatory support, multiple organ function preservation, glucocorticoid use, renal replacement therapy, anticoagulation, and restrictive fluid management was the main treatment strategy. Early recognition and intervention, multidisciplinary collaboration, multi-organ function support, and personalized treatment might be the key for reducing mortality.

Neurological Sequelae in Patients with COVID-19: A Histopathological Perspective

BACKGROUND

Neuroinvasive properties of SARS-CoV-2 have allowed the hypothesis of several pathogenic mechanisms related to acute and chronic neurological sequelae. However, neuropathological correlates have been poorly systematically investigated, being retrieved from reports of single case or limited case series still.

METHODS

A PubMed search was carried out to review all publications on autopsy in subjects with "COronaVIrus Disease-19" (COVID-19). Among them, we focused on histological findings of the brain, which were compared with those from the authors' autoptic studies performed in some COVID-19 patients.

RESULTS

Only seven studies reported histological evidence of brain pathology in patients deceased for COVID-19, including three with reverse transcription-quantitative polymerase chain reaction evidence of viral infection. All these studies, in line with our experience, showed vascular-related and infection-related secondary inflammatory tissue damage due to an abnormal immune response. It is still unclear, however, whether these findings are the effect of a direct viral pathology or rather reflect a non-specific consequence of cardiovascular and pulmonary disease on the brain.

CONCLUSIONS

Notwithstanding the limited evidence available and the heterogeneity of the studies, we provide a preliminary description of the relationship between SARS-CoV-2 and brain sequelae. Systematic autoptic investigations are needed for accurate detection and adequate management of these patients.

Neurological Sequelae in Patients with COVID-19: A Histopathological Perspective

BACKGROUND

Neuroinvasive properties of SARS-CoV-2 have allowed the hypothesis of several pathogenic mechanisms related to acute and chronic neurological sequelae. However, neuropathological correlates have been poorly systematically investigated, being retrieved from reports of single case or limited case series still.

METHODS

A PubMed search was carried out to review all publications on autopsy in subjects with "COronaVIrus Disease-19" (COVID-19). Among them, we focused on histological findings of the brain, which were compared with those from the authors' autoptic studies performed in some COVID-19 patients.

RESULTS

Only seven studies reported histological evidence of brain pathology in patients deceased for COVID-19, including three with reverse transcription-quantitative polymerase chain reaction evidence of viral infection. All these studies, in line with our experience, showed vascular-related and infection-related secondary inflammatory tissue damage due to an abnormal immune response. It is still unclear, however, whether these findings are the effect of a direct viral pathology or rather reflect a non-specific consequence of cardiovascular and pulmonary disease on the brain.

CONCLUSIONS

Notwithstanding the limited evidence available and the heterogeneity of the studies, we provide a preliminary description of the relationship between SARS-CoV-2 and brain sequelae. Systematic autoptic investigations are needed for accurate detection and adequate management of these patients.

Incidence, risk factors, and thrombotic load of pulmonary embolism in patients hospitalized for COVID-19 infection

OBJECTIVE

To determine the incidence, characteristics, and risk factors of pulmonary embolism (PE) among patients hospitalized for COVID-19.

PATIENTS AND METHODS

We performed a prospective observational study of a randomly selected cohort of consecutive patients hospitalized for COVID-19 infection between March 8, 2020 through April 25, 2020. All eligible patients underwent a computed tomography pulmonary angiography independently of their PE clinical suspicion and were pre-screened for a baseline elevated D-dimer level.

RESULTS

119 patients were randomly selected from the 372 admitted to one tertiary hospital in Valencia (Spain) for COVID-19 infection during the period of study. Seventy-three patients fulfilled both the inclusion criteria and none of the exclusion criteria and were finally included in the study. Despite a high level of pharmacological thromboprophylaxis (89%), the incidence of PE was 35.6% (95% confidence interval [CI], 29.6 to 41.6%), mostly with a peripheral location and low thrombotic load (Qanadli score 18.5%). Multivariate analysis showed that heart rate (Hazard Ratio [HR], 1.04), room-air oxygen saturation (spO2) (HR, 0.87), D-dimer (HR, 1.02), and C-reactive protein (CRP) levels (HR, 1.01) at the time of admission were independent predictors of incident PE during hospitalization. A risk score was constructed with these four variables showing a high predictive value of incident PE (AUC-ROC: 0.86; 95% CI: 0.80 to 0.93).

CONCLUSIONS

Our findings confirmed a high incidence of PE in hospitalized COVID-19 patients. Heart rate, spO2, D-dimer, and CRP levels at admission were associated with higher rates of PE during hospitalization.

Thrombosis and Coagulopathy in COVID-19: Current Understanding and Implications for Antithrombotic Treatment in Patients Treated With Percutaneous Coronary Intervention

Coronavirus disease 2019 (COVID-19), a respiratory syndrome, is a global pandemic. Therefore, there is an urgent need to explore mechanisms implicated in the pathogenesis of the disease. Clinical and autopsy studies show a complex chain of events preceding COVID-19-related death. The disease is characterized by endothelial dysfunction, platelet activation, thrombosis, coagulopathy, and multiple organ failure. Globally, millions of patients with coronary heart disease undergo percutaneous coronary intervention (PCI) each year. These patients undergo high-intensity antithrombotic therapy during hospitalization and dual antiplatelet therapy (DAPT) for at least 6 months post PCI. COVID-19 is characterized by changes in platelet counts. Treatment of ischemic events that occur during stent implantation is associated with bleeding complications in patients following PCI complicated by COVID-19. This review summarizes recent progress in activation status and levels of COVID-19-related platelet changes. These findings will provide information on the effectiveness of antithrombotic therapy for the management of platelet changes in COVID-19 patients.

Management of acute coronary syndrome in the context of coronavirus disease 2019

Coronavirus disease 2019 (COVID-19) is still developing worldwide. The prognosis of the disease will become worse and mortality will be even higher when it is combined with cardiovascular disease. Furthermore, COVID-19 is highly infectious and requires strict isolation measures. For acute coronary syndromes (ACS), a common cardiovascular disease, infection may aggravate the occurrence and development of ACS, making the management of more difficult. It will be an enormous challenge for clinical practice to deal with ACS in this setting of COVID-19.Aim to reduce the mortality of ACS patients during the epidemic of COVID-19 by standardizing procedures as much as possible.Pubmed and other relevant databases were searched to retrieve articles on COVID-19 and articles on ACS management strategies during previous influenza epidemics. The data was described and synthesized to summarize the diagnosis and management strategy of ACS, the preparation of catheter laboratory, and the protection of the medical staff in the context of COVID-19. Ethical approval is not required in this study, because it is a review with no recourse to patient identifiable information.Standardized diagnosis and treatment advice can help reduce the mortality of COVID-19 patients with ACS. In the absence of contraindications, the third generation of thrombolytic drugs should be the first choice for thrombolytic treatment in the isolation ward. For patients who have to receive PCI, this article provides detailed protective measures to avoid nosocomial infection.

Regular Use of VKA Prior to COVID-19 Associated with Lower 7-Day Survival in Hospitalized Frail Elderly COVID-19 Patients: The GERIA-COVID Cohort Study

Background. Vitamin K concentrations are inversely associated with the clinical severity of COVID-19. The objective of this cohort study was to determine whether the regular use of vitamin K antagonist (VKA) prior to COVID-19 was associated with short-term mortality in frail older adults hospitalized for COVID-19. Methods. Eighty-two patients consecutively hospitalized for COVID-19 in a geriatric acute care unit were included. The association of the regular use of VKA prior to COVID-19 with survival after 7 days of COVID-19 was examined using a propensity-score-weighted Cox proportional-hazards model accounting for age, sex, severe undernutrition, diabetes mellitus, hypertension, prior myocardial infarction, congestive heart failure, prior stroke and/or transient ischemic attack, CHA2DS2-VASc score, HAS-BLED score, and eGFR. Results. Among 82 patients (mean ± SD age 88.8 ± 4.5 years; 48% women), 73 survived COVID-19 at day 7 while 9 died. There was no between-group difference at baseline, despite a trend for more frequent use of VKA in those who did not survive on day 7 (33.3% versus 8.2%, p = 0.056). While considering “using no VKA” as the reference (hazard ratio (HR) = 1), the HR for 7-day mortality in those regularly using VKA was 5.68 [95% CI: 1.17; 27.53]. Consistently, COVID-19 patients using VKA on a regular basis had shorter survival times than the others (p = 0.031). Conclusions. Regular use of VKA was associated with increased mortality at day 7 in hospitalized frail elderly patients with COVID-19.

Low Detection Rate of Pulmonary Embolism in Patients Presenting to the Emergency Department With Suspected Coronavirus Disease 2019 (COVID-19): A Single-Centre UK Study

Purpose

Critically ill patients with coronavirus disease 2019 (COVID-19) are at increased risk of thrombosis. There are limited data on PE rates in COVID-19 patients at presentation to the emergency department (ED). In this study, we evaluated the detection rates of PE in patients presenting to the ED with suspected and proven COVID-19.

Methods

A single-centre retrospective study was undertaken of 285 consecutive patients undergoing CT pulmonary angiogram (CTPA) in the Emergency Department at Nottingham University Hospitals NHS Trust in the United Kingdom between 25 March and 30 April 2020. At our institution, CTPA is performed in all patients undergoing CT for triage. The study group consisted of patients considered COVID-19 positive based on polymerase chain reaction (PCR) results and CTPA findings. The detection rate of PE in COVID-19 patients was compared to patients undergoing CTPA for suspected PE only and for suspected COVID-19 with no COVID CT findings and negative PCR (control group 1); and CTPAs prior to the coronavirus pandemic (control group 2).

Results

One of 48 patients in the study group had a PE (2%) compared to 25/215 (12%) in control group 1 and 10/50 (20%) in control group 2. Prevalence of PE in the study group was lower than in control group 1 (P = 0.058) and compared to control group 2 (P = 0.005). Eleven patients undergoing CTPA had negative PCR but positive CT for COVID-19.

Conclusion

Detection rate of pulmonary embolus is low in patients with COVID-19 undergoing CTPA on a triage pathway.