Thrombotic microangiopathy with kidney involvement in a patient with coronavirus disease 2019: A case report and literature review (preprint)

Background and aim: Millions of people worldwide have suffered from coronavirus disease 2019 (COVID-19). COVID-19 can lead to coagulopathy and thrombosis, presenting as pulmonary artery thromboembolism, deep vein thrombosis, and thrombotic microangiopathy (TMA), the latter being a rare finding in affected patients’ kidneys. Prior reports have rarely addressed the pathophysiology, clinical presentations, and therapeutic options in patients with COVID-19-associated TMA. Case presentation: We herein described a case of renal biopsy-proven TMA after COVID-19 in a 36-year-old woman. Initial examination revealed inflammation, acute kidney injury (AKI), anemia, and thrombocytopenia. She was diagnosed with hemolytic uremic syndrome, pulmonary infection, and COVID-19. After treatment, her condition stabilized but remained hemodialysis-dependent after discharge. One week later, she was re-hospitalized, and physical examination showed anemia and bilateral lower extremity edema. Abdominal ultrasound showed increased bilateral kidney echogenicity. Whole-exome sequencing detected an unknown variant of the C3 gene associated with hemolytic uremic syndrome susceptibility type 5/complement C3 deficiency. Kidney biopsy showed renal artery lesions, including small arteriole endothelial swelling, intimal thickening, mucinous degeneration, luminal occlusion, and small arterial wall necrosis. She received plasma exchange and steroids with significant renal function recovery. Conclusion: TMA likely contributed to AKI after COVID-19,thus supporting the notion that TMA plays an important role in the pathogenesis of COVID-19-related kidney injury. When diagnosing and treating COVID-19 patients with abnormal renal function, clinicians should incorporate kidney biopsy and genetic testing for the complement system, identify renal-limited and systemic TMA, and treat accordingly, which can improve patient outcomes.

Common coronary artery occlusions in patients with myocardial infarction.

Introduction: coronary artery disease (CAD) is a significant cardiovascular disease (CVD) that affects people worldwide. This study aimed to determine the main occluded coronary arteries in patients with myocardial infarction in Najran, Kingdom of Saudi Arabia (KSA). Methods: a retrospective cross-sectional study conducted between March 2020 and March 2021 and involving 661 myocardial infarction patients recruited from two hospitals (King Khalid Hospital and Prince Sultan Centre for Healthcare in Najran) used sampling for enrolled patients. Patients over the age of 15 years, current residents of KSA, and diagnosed with coronary artery occlusion based on at least one identifiable coronary lesion on a coronary angiography were considered eligible. We created generalized linear mixed models to investigate patients´ clinical and coronary angiographic features and identify statistically relevant components. Results: there were 661 CAD cases in this study: 548 (82.9%) males and 113 (17.1%) females, with a mean and standard deviation (SD) age of 4.03 ± 1.370 years. Ages of the 661 participants ranged from 15 to 85, who had been diagnosed with myocardial infarction were evaluated. It was found that most of the patients were in the 55-64 age range. The majority of cases (366 (55.4%) had ST-segment elevation myocardial infarction (STEMI), 187 (28.3%) had non-ST-segment elevation (NSTEMI), 101 (15.3%) had acute coronary syndrome-non-ST-segment elevation (ACS-NSTEMI), and 7 (1.1%) had acute coronary syndrome-ST-segment elevation (ACS-STEMI). Conclusion: the left anterior descending artery (LAD) is the commonest lesion found in both ST-segment elevation and non-ST-segment elevation myocardial infarction patients.

Periocular Biometrics: A Modality for Unconstrained Scenarios (preprint)

Periocular refers to the externally visible region of the face that surrounds the eye socket. This feature-rich area can provide accurate identification in unconstrained or uncooperative scenarios, where the iris or face modalities may not offer sufficient biometric cues due to factors such as partial occlusion or high subject-to-camera distance. The COVID-19 pandemic has further highlighted its importance, as the ocular region remained the only visible facial area even in controlled settings due to the widespread use of masks. This paper discusses the state of the art in periocular biometrics, presenting an overall framework encompassing its most significant research aspects, which include: (a) ocular definition, acquisition, and detection; (b) identity recognition, including combination with other modalities and use of various spectra; and (c) ocular soft-biometric analysis. Finally, we conclude by addressing current challenges and proposing future directions.

CoronaViz: Visualizing Multilayer Spatiotemporal COVID-19 Data with Animated Geocircles (preprint)

While many dashboards for visualizing COVID-19 data exist, most separate geospatial and temporal data into discrete visualizations or tables. Further, the common use of choropleth maps or space-filling map overlays supports only a single geospatial variable at once, making it difficult to compare the temporal and geospatial trends of multiple, potentially interacting variables, such as active cases, deaths, and vaccinations. We present CoronaViz, a COVID-19 visualization system that conveys multilayer, spatiotemporal data in a single, interactive display. CoronaViz encodes variables with concentric, hollow circles, termed geocircles, allowing multiple variables via color encoding and avoiding occlusion problems. The radii of geocircles relate to the values of the variables they represent via the psychophysically determined Flannery formula. The time dimension of spatiotemporal variables is encoded with sequential rendering. Animation controls allow the user to seek through time manually or to view the pandemic unfolding in accelerated time. An adjustable time window allows aggregation at any granularity, from single days to cumulative values for the entire available range. In addition to describing the CoronaViz system, we report findings from a user study comparing CoronaViz with multi-view dashboards from the New York Times and Johns Hopkins University. While participants preferred using the latter two dashboards to perform queries with only a geospatial component or only a temporal component, participants uniformly preferred CoronaViz for queries with both spatial and temporal components, highlighting the utility of a unified spatiotemporal encoding. CoronaViz is open-source and freely available at http://coronaviz.umiacs.io.

Hyperhomocysteinemia is related to large vessel occlusion in young patients with COVID-19, two case reports (preprint)

We report two cases of previously healthy young men with COVID-19 infection who developed acute ischemic stroke due to large vessel occlusion followed by secondary events concerning for a further thromboembolic event. We hypothesize that the hypercoagulable state related to COVID-19 exacerbated the underlying hereditary thrombophilia due to MTHFR-gene mutation.

SARS-CoV-2 variants impact RBD conformational dynamics and ACE2 accessibility (preprint)

The coronavirus disease 2019 (COVID-19) pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has killed over 5 million people and is causing a devastating social and economic impact all over the world. The rise of new variants of concern (VOCs) represents a difficult challenge due to the loss vaccine and natural immunity, and increased transmissibility. All circulating VOCs contain mutations in the spike glycoprotein, which mediates fusion between the viral and host cell membranes, via its receptor binding domain (RBD) that binds to angiotensin-converting enzyme 2 (ACE2). In an attempt to understand the effect of RBD mutations in circulating VOCs, a lot of attention has been given to the RBD-ACE2 interaction. However, this type of analysis is limited, since it ignores more indirect effects, such as the conformational dynamics of the RBD itself. Observing that some VOCs mutations occur in residues that are not in direct contact with ACE2, we hypothesized that they could affect RBD conformational dynamics. To test this, we performed long atomistic (AA) molecular dynamics (MD) simulations to investigate the structural dynamics of wt RBD, and that of three circulating VOCs (alpha, beta, and delta). Our results show that in solution, wt RBD presents two distinct conformations: an open conformation where it is free to bind ACE2; and a closed conformation, where the RBM ridge blocks the binding surface. The alpha and beta variants significantly impact the open/closed equilibrium, shifting it towards the open conformation by roughly 20%. This shift likely increases ACE2 binding affinity. Simulations of the currently predominant delta variant RBD were extreme in this regard, in that a closed conformation was never observed. Instead, the system alternated between the before mentioned open conformation and an alternative reversed one, with a significantly changed orientation of the RBM ridge flanking the RBD. This alternate conformation could potentially provide a fitness advantage not only due to increased availability for ACE2 binding, but also by aiding antibody escape through epitope occlusion. These results support the hypothesis that VOCs, and particularly the delta variant, impact RBD conformational dynamics in a direction that simultaneously promotes efficient binding to ACE2 and antibody escape.

Recurrent coronary thrombotic events in a moderate case of COVID-19.

We describe the case of a healthy patient with moderate COVID-19 infection without thrombophilia nor coronary disease background who presented with a relapsing thrombotic occlusion of the right coronary artery despite normal oxygenation, adequate antiaggregation and prophylactic anticoagulation. Prophylactic anticoagulation recommendations in COVID-19 were inadequate for this patient. Further data are needed to propose full-dose therapeutic anticoagulation for patients with coronary thrombosis and COVID-19 infection. This could nevertheless be considered even in mild forms of COVID-19.

Unusual arterial thrombotic events in Covid-19 patients.

INTRODUCTION: COVID-19 infection is commonly complicated with pro-thrombotic state and endothelial dysfunction. While several studies reported a high incidence of venous thromboembolic events. The occurrence of arterial thromboses are yet rarely described and could be underestimated. OBJECTIVES: To describe the clinical and biological characteristics of COVID-19 patients presenting with an associated arterial thromboembolic event. MATERIAL AND METHODS: We performed a retrospective multicentric study in 3 centers between France and Italy. All patients with a confirmed SARS-CoV-2 infection and arterial thromboembolic events were included in the analysis. RESULTS: From March 8th to April 25th 2020, we identified 20 patients (24 events) with arterial thromboembolic events over 209 admitted patients (9.6%) with severe COVID-19 infection. Arterial thrombotic events included acute coronary occlusions (n = 9), stroke (n = 6), limb ischemia (n = 3), splenic infarcts (n = 3), aortic thrombosis (n = 2) and occlusive mesenteric ischemia (n = 1). At the time of the event, 10/20 (50%) of patients received thromboprohylaxis, 2/20 (10%) were receiving treatment dose anticoagulation and 5/20 (25%) were receiving antiplatelet therapy. CONCLUSION: Our observations suggest that serious arterial thrombotic events might occur in Covid-19 patients. However, the exact incidence of such events and the best way to prevent them yet remains to be investigated.

Landmark Guidance Independent Spatio-channel Attention and Complementary Context Information based Facial Expression Recognition (preprint)

A recent trend to recognize facial expressions in the real-world scenario is to deploy attention based convolutional neural networks (CNNs) locally to signify the importance of facial regions and, combine it with global facial features and/or other complementary context information for performance gain. However, in the presence of occlusions and pose variations, different channels respond differently, and further that the response intensity of a channel differ across spatial locations. Also, modern facial expression recognition(FER) architectures rely on external sources like landmark detectors for defining attention. Failure of landmark detector will have a cascading effect on FER. Additionally, there is no emphasis laid on the relevance of features that are input to compute complementary context information. Leveraging on the aforementioned observations, an end-to-end architecture for FER is proposed in this work that obtains both local and global attention per channel per spatial location through a novel spatio-channel attention net (SCAN), without seeking any information from the landmark detectors. SCAN is complemented by a complementary context information (CCI) branch. Further, using efficient channel attention (ECA), the relevance of features input to CCI is also attended to. The representation learnt by the proposed architecture is robust to occlusions and pose variations. Robustness and superior performance of the proposed model is demonstrated on both in-lab and in-the-wild datasets (AffectNet, FERPlus, RAF-DB, FED-RO, SFEW, CK+, Oulu-CASIA and JAFFE) along with a couple of constructed face mask datasets resembling masked faces in COVID-19 scenario. Codes are publicly available at https://github.com/1980x/SCAN-CCI-FER

Successful coronary artery bypass operation in a SARS-COV-2 infected patient with acute coronary syndrome.

The coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is overwhelming healthcare resources and infrastructure worldwide. Earlier reports have demonstrated complicated postoperative courses and high fatality rates in patients undergoing emergent cardiothoracic surgery who were diagnosed postoperatively with COVID-19. These reports raise the possibility that active COVID-19 might precipitate a catastrophic pathophysiological response to infection in the postoperative period and lead to unfavorable surgical outcomes. Hence, it is imperative to screen patients with SARS-CoV-2 infection before surgery and to carefully monitor them in the postoperative period to identify any signs of active COVID-19. In this report, we present the successful outcome of coronary artery bypass grafting (CABG) operation in a patient with asymptomatic SARS-CoV-2 infection presenting with an acute coronary syndrome and requiring urgent surgical intervention. We employed a thorough strategy to identify subclinical COVID-19 disease, and after confirming the absence of active disease, proceeded with the CABG operation. The patient outcome was successful with the absence of any overt COVID-19 manifestations in the postoperative period.