Venous Thrombosis Among Critically Ill Patients With Coronavirus Disease 2019 (COVID-19)

Simultaneous portal vein thrombosis and splenic vein thrombosis in a COVID-19 patient: A case report and review of literature

BACKGROUND

It is well-described that COVID-19 infection is associated with an increased risk of thrombotic complications. While there have been many cases of pulmonary emboli and deep vein thrombosis in these patients, reports of COVID-19 associated portal vein thrombosis (PVT) have been uncommon. We present a unique case of concomitant PVT and splenic artery thrombosis in a COVID-19 patient.

CASE SUMMARY

A 77-year-old-male with no history of liver disease presented with three days of left-sided abdominal pain. One week earlier, the patient was diagnosed with mildly symptomatic COVID-19 and was treated with nirmatrelvir/ritonavir. Physical exam revealed mild right and left lower quadrant tenderness, but was otherwise unremarkable. Significant laboratory findings included white blood cell count 12.5 K/μL, total bilirubin 1.6 mg/dL, aminoaspartate transferase 40 U/L, and alanine aminotransferase 61 U/L. Computed tomography of the abdomen and pelvis revealed acute PVT with thrombus extending from the distal portion of the main portal vein into the right and left branches. Also noted was a thrombus within the distal portion of the splenic artery with resulting splenic infarct. Hypercoagulable workup including prothrombin gene analysis, factor V Leiden, cardiolipin antibody, and JAK2 mutation were all negative. Anticoagulation with enoxaparin was initiated, and the patient’s pain improved. He was discharged on apixaban.

CONCLUSION

It is quite uncommon for PVT to present simultaneously with an arterial thrombotic occlusion, as in the case of our patient. Unusual thrombotic manifestations are classically linked to hypercoagulable states including malignancy and hereditary and autoimmune disorders. Viral infections such as Epstein-Barr virus, cytomegalovirus, viral hepatitis, and COVID-19 have all been found to increase the risk of splanchnic venous occlusions, including PVT. In our patient, prompt abdominal imaging led to early detection of thrombus, early treatment, and an excellent outcome. This case is unique in that it is the second known case within the literature of simultaneous PVT and splenic artery thrombosis in a COVID-19 patient.

Cervical Spine Surgery Following COVID-19 Infection: When is it Safe to Proceed?

STUDY DESIGN

Retrospective.

OBJECTIVE

We utilized the NIH National COVID Cohort Collaborative (N3C) database to characterize the risk profile of patients undergoing spine surgery during multiple time windows following the COVID-19 infection.

SUMMARY OF BACKGROUND DATA

While the impact of COVID-19 on various organ systems is well documented, there is limited knowledge regarding its effect on perioperative complications following spine surgery or the optimal timing of surgery after an infection.

METHODS

We asked the National COVID Cohort Collaborative for patients who underwent cervical spine surgery. Patients were stratified into those with an initial documented COVID-19 infection within 3 time periods: 0-2 weeks, 2-6 weeks, or 6-12 weeks before surgery.

RESULTS

A total of 29,449 patients who underwent anterior approach cervical spine surgery and 46,379 patients who underwent posterior approach cervical spine surgery were included. Patients who underwent surgery within 2 weeks of their COVID-19 diagnosis had a significantly increased risk for venous thromboembolic events, sepsis, 30-day mortality, and 1-year mortality, irrespective of the anterior or posterior approach. Among patients undergoing surgery between 2 and 6 weeks after COVID-19 infection, the 30-day mortality risk remained elevated in patients undergoing a posterior approach only. Patients undergoing surgery between 6 and 12 weeks from the date of the COVID-19 infection did not show significantly elevated rates of any complications analyzed.

CONCLUSIONS

Patients undergoing either anterior or posterior cervical spine surgery within 2 weeks from the initial COVID-19 diagnosis are at increased risk for perioperative venous thromboembolic events, sepsis, and mortality. Elevated perioperative complication risk does not persist beyond 2 weeks, except for 30-day mortality in posterior approach surgeries. On the basis of these results, it may be warranted to postpone nonurgent spine surgeries for at least 2 weeks following a COVID-19 infection and advise patients of the increased perioperative complication risk when urgent surgery is required.

Specific and Non-specific Aspects and Future Challenges of ICU Care Among COVID-19 Patients with Obesity: A Narrative Review

PURPOSE OF REVIEW

Since the end of 2019, the coronavirus disease 2019 (COVID-19) pandemic has infected nearly 800 million people and caused almost seven million deaths. Obesity was quickly identified as a risk factor for severe COVID-19, ICU admission, acute respiratory distress syndrome, organ support including mechanical ventilation and prolonged length of stay. The relationship among obesity; COVID-19; and respiratory, thrombotic, and renal complications upon admission to the ICU is unclear.

RECENT FINDINGS

The predominant effect of a hyperinflammatory status or a cytokine storm has been suggested in patients with obesity, but more recent studies have challenged this hypothesis. Numerous studies have also shown increased mortality among critically ill patients with obesity and COVID-19, casting doubt on the obesity paradox, with survival advantages with overweight and mild obesity being reported in other ICU syndromes. Finally, it is now clear that the increase in the global prevalence of overweight and obesity is a major public health issue that must be accompanied by a transformation of our ICUs, both in terms of equipment and human resources. Research must also focus more on these patients to improve their care. In this review, we focused on the central role of obesity in critically ill patients during this pandemic, highlighting its specificities during their stay in the ICU, identifying the lessons we have learned, and identifying areas for future research as well as the future challenges for ICU activity.

Incidence rates of thrombosis with thrombocytopenia syndrome (TTS) among adults in United States commercial and Medicare claims databases, 2017-2020

BACKGROUND

Increased risk of thrombosis with thrombocytopenia syndrome (TTS) following adenovirus vector-based COVID-19 vaccinations has been identified in passive surveillance systems. TTS incidence rates (IRs) in the United States (U.S.) are needed to contextualize reports following COVID-19 vaccination.

METHODS

We estimated annual and monthly IRs of overall TTS, common site TTS, and unusual site TTS for adults aged 18-64 years in Carelon Research and MarketScan commercial claims (2017-Oct 2020), CVS Health and Optum commercial claims (2019-Oct 2020), and adults aged ≥ 65 years using CMS Medicare claims (2019-Oct 2020); IRs were stratified by age, sex, and race/ethnicity (CMS Medicare).

RESULTS

Across data sources, annual IRs for overall TTS were similar between Jan-Dec 2019 and Jan-Oct 2020. Rates were higher in Medicare (IRs: 370.72 and 365.63 per 100,000 person-years for 2019 and 2020, respectively) than commercial data sources (MarketScan IRs: 24.21 and 24.06 per 100,000 person-years; Optum IRs: 32.60 and 31.29 per 100,000 person-years; Carelon Research IRs: 24.46 and 26.16 per 100,000 person-years; CVS Health IRs: 30.31 and 30.25 per 100,000 person-years). Across years and databases, common site TTS IRs increased with age and were higher among males. Among adults aged ≥ 65 years, the common site TTS IR was highest among non-Hispanic black adults. Annual unusual site TTS IRs ranged between 2.02 and 3.04 (commercial) and 12.49 (Medicare) per 100,000 person-years for Jan-Dec 2019; IRs ranged between 1.53 and 2.67 (commercial) and 11.57 (Medicare) per 100,000 person-years for Jan-Oct 2020. Unusual site TTS IRs were higher in males and increased with age in commercial data sources; among adults aged ≥ 65 years, IRs decreased with age and were highest among non-Hispanic American Indian/Alaska native adults.

CONCLUSION

TTS IRs were generally similar across years, higher for males, and increased with age. These rates may contribute to surveillance of post-vaccination TTS.

Thromboembolic complications after COVID-19 in kidney transplant recipients

AIM

Increased venous thrombosis and arterial embolism rates are observed in the general population during or after COVID-19. Data regarding the kidney transplant population are scarce. In this study, we aim to investigate the thrombotic complications and risk factors associated with thrombotic complications in kidney transplant patients.

METHODS

This retrospective observational study included adult kidney transplant recipients diagnosed with COVID-19 between March 2020 and June 2022. The endpoint was the occurrence of thromboembolic events.

RESULTS

Four hundred and sixty-nine patients were followed for a median of 10.8 months after COVID-19. Forty patients (8.5%) died. Thromboembolic complications developed in 51 (11.9%) of the surviving patients. Twenty-four patients with thromboembolic events were receiving prophylactic anticoagulation before the event. The patients with mild, moderate, and severe COVID-19 were 292, 129, and 48, respectively. Patients with moderate COVID-19 had a significantly higher percentage of thromboembolic complications than patients with mild COVID-19. Older age, prior heart disease, and moderate COVID-19 were significantly associated with thromboembolic events. The incidence of thromboembolic events after COVID-19 is 10.9 per 100 patient-year.

CONCLUSION

Thromboembolic complications were observed at increased rates in kidney transplant recipients after COVID-19. Therefore, prospective and cohort studies for post-COVID-19 complications regarding the treatment modalities are urgently needed.

Comparing COVID-19 and influenza: Epidemiology, clinical characteristics, outcomes and mortality in the ICU

RATIONALE

Several authors have compared COVID-19 infection with influenza in the ICU.

OBJECTIVE

This study aimed to compare the baseline clinical profiles, care procedures, and mortality outcomes of patients admitted to the intensive care unit, categorized by infection status (Influenza vs. COVID-19).

METHODS

Retrospective observational study. Data were extracted from the Toulouse University Hospital from March 2014 to March 2021. To compare survival curves, we plotted the survival at Day-90 using the Kaplan-Meier curve and conducted a log-rank test. Additionally, we performed propensity score matching to adjust for confounding factors between the COVID-19 and influenza groups. Furthermore, we use the CART model for multivariate analysis.

RESULTS

The study included 363 patients admitted to the ICU due to severe viral pneumonia: 152 patients (41.9 %) with influenza and 211 patients (58.1 %) with COVID-19. COVID-19 patients exhibited a higher prevalence of cardiovascular risk factors, whereas influenza patients had significantly higher severity scores (SOFA: 10 [6-12] vs. 6 [3-9], p<0.01 and SAPS II: 51 [35-67] vs. 37 [29-50], p<0.001). Overall mortality rates were comparable between the two groups (27.6 % (n = 42) in the influenza group vs. 21.8 % (n = 46) in the COVID-19 group, p=NS). Mechanical ventilation was more commonly employed in the influenza group (76.3 % (n = 116) vs. 59.7 % (n = 126), p<0.001); however, COVID-19 patients required longer durations of mechanical ventilation (18 [9-29] days vs. 13 [5-24] days, p<0.006) and longer hospital stays (23 [13-34] days vs. 18.5 [9-34.5] days, p = 0.009). The CART analysis revealed that the use of extra renal replacement therapy was the most influential prognostic factor in the influenza group, while the PaO2/FiO2-PEEP ratio played a significant role in the COVID-19 group.

CONCLUSIONS

Despite differences in clinical presentation and prognostic factors, the mortality rates at 90 days, after adjusting for confounding factors, were similar between COVID-19 and influenza patients.

A temporal analysis of perioperative complications following COVID-19 infection in patients undergoing lumbar spinal fusion: When is it safe to proceed?

Background Context

COVID-19 has been shown to adversely affect multiple organ systems, yet little is known about its effect on perioperative complications after spine surgery or the optimal timing of surgery after an infection. We used the NIH National COVID Cohort Collaborative (N3C) database to characterize the risk profile in patients undergoing spine surgery during multiple time windows following COVID-19 infection.

Methods

We queried the National COVID Cohort Collaborative, a database of 17.4 million persons with 6.9 million COVID-19 cases, for patients undergoing lumbar spinal fusion surgery. Patients were stratified into those with an initial documented COVID-19 infection within 3 time periods: 0 to 2 weeks, 2 to 6 weeks, or 6 to 12 weeks before surgery.

Results

A total of 60,541 patients who underwent lumbar spinal fusion procedures were included. Patients who underwent surgery within 2 weeks of their COVID-19 diagnosis had a significantly increased risk for venous thromboembolic events (OR 2.29, 95% CI 1.58-3.32), sepsis (OR 1.56, 95% CI 1.03-2.36), 30-day mortality (OR 5.55, 95% CI 3.53-8.71), and 1-year mortality (OR 2.70, 95% CI 1.91-3.82) compared with patients who were COVID negative during the same period. There was no significant difference in the rates of acute kidney injury or surgical site infection. Patients undergoing surgery between 2 and 6 weeks or between 6 and 12 weeks from the date of COVID-19 infection did not show significantly elevated rates of any complication analyzed.

Conclusions

Patients undergoing lumbar spinal fusion within 2 weeks from initial COVID-19 diagnosis are at increased risk for perioperative venous thromboembolic events and sepsis. This effect does not persist beyond 2 weeks, however, so it may be warranted to postpone non-urgent spine surgeries for at least 2 weeks following a COVID-19 infection or to consider a more aggressive VTE chemoprophylaxis regimen for urgent surgery in COVID-19 patients.

Deep learning, 3D ultrastructural analysis reveals quantitative differences in platelet and organelle packing in COVID-19/SARSCoV2 patient-derived platelets

Platelets contribute to COVID-19 clinical manifestations, of which microclotting in the pulmonary vasculature has been a prominent symptom. To investigate the potential diagnostic contributions of overall platelet morphology and their α-granules and mitochondria to the understanding of platelet hyperactivation and micro-clotting, we undertook a 3D ultrastructural approach. Because differences might be small, we used the high-contrast, high-resolution technique of focused ion beam scanning EM (FIB-SEM) and employed deep learning computational methods to evaluate nearly 600 individual platelets and 30 000 included organelles within three healthy controls and three severely ill COVID-19 patients. Statistical analysis reveals that the α-granule/mitochondrion-to-plateletvolume ratio is significantly greater in COVID-19 patient platelets indicating a denser packing of organelles, and a more compact platelet. The COVID-19 patient platelets were significantly smaller -by 35% in volume - with most of the difference in organelle packing density being due to decreased platelet size. There was little to no 3D ultrastructural evidence for differential activation of the platelets from COVID-19 patients. Though limited by sample size, our studies suggest that factors outside of the platelets themselves are likely responsible for COVID-19 complications. Our studies show how deep learning 3D methodology can become the gold standard for 3D ultrastructural studies of platelets.

Differential platelet activation through an interaction with spike proteins of different SARS-CoV-2 variants

COVID-19 disease is associated with an increased risk of thrombotic complications, which contribute to high short-term mortality. Patients with COVID-19 demonstrate enhanced platelet turnover and reactivity, which may have a role in the development of thrombotic events and disease severity. Evidence has suggested direct interaction between SARS-CoV-2 and platelets, resulting in platelets activation. Here, we compare the effect of various SARS-CoV-2 spike variants on platelet activation. Engineered lentiviral particles were pseudotyped with spike SARS-CoV-2 variants and incubated with Platelet Rich Plasma obtained from healthy individuals. The pseudotyped SARS-CoV-2 exhibiting the wild-type Wuhan-Hu spike protein stimulated platelets to increase expression of the surface CD62P and activated αIIbβ3 markers by 3.5 ± 1.2 and 3.3 ± 0.7 fold, respectively (P = 0.004 and 0.003). The Delta variant induced much higher levels of platelet activation; CD62P expression was increased by 6.6 ± 2.2 fold and activated αIIbβ3 expression was increased by 5.0 ± 1.5 fold (P = 0.005 and 0.026, respectively). The Omicron BA.1 and the Alpha variants induced the lowest level of activation; CD62P expression was increased by 1.7 ± 0.4 and 1.6 ± 0.9 fold, respectively (P = 0.003 and 0.008), and activated αIIbβ3 expression by 1.8 ± 1.1 and 1.6 ± 0.8, respectively (P = 0.003 and 0.001). The Omicron BA.2 variant induced an increase of platelets activation comparable to the Wuhan-Hu (2.8 ± 1.2 and 2.1 ± 1.3 fold for CD62P and activated αIIbβ3 markers, respectively). The results obtained for various COVID-19 variants are in correlation with the clinical severity and mortality reported for these variants.

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.

Coagulopathy and thromboembolic events a pathogenic mechanism of COVID-19 associated with mortality: An updated review

During 2019, the SARS-CoV-2 emerged from China, and during months, COVID-19 spread in many countries around the world. The expanding data about pathogenesis of this virus could elucidate the exact mechanism by which COVID-19 caused death in humans. One of the pathogenic mechanisms of this disease is coagulation. Coagulation disorders that affect both venous and arterial systems occur in patients with COVID-19. The possible mechanism involved in the coagulation could be excessive inflammation induced by SARS-CoV-2. However, it is not yet clear well how SARS-CoV-2 promotes coagulopathy. However, some factors, such as pulmonary endothelial cell damage and some anticoagulant system disorders, are assumed to have an important role. In this study, we assessed conducted studies about COVID-19-induced coagulopathy to obtain clearer vision of the wide range of manifestations and possible pathogenesis mechanisms.

Interrelationship between COVID-19 and Coagulopathy: Pathophysiological and Clinical Evidence

Since the first description of COVID-19 infection, among clinical manifestations of the disease, including fever, dyspnea, cough, and fatigue, it was observed a high incidence of thromboembolic events potentially evolving towards acute respiratory distress syndrome (ARDS) and COVID-19-associated-coagulopathy (CAC). The hypercoagulation state is based on an interaction between thrombosis and inflammation. The so-called CAC represents a key aspect in the genesis of organ damage from SARS-CoV-2. The prothrombotic status of COVID-19 can be explained by the increase in coagulation levels of D-dimer, lymphocytes, fibrinogen, interleukin 6 (IL-6), and prothrombin time. Several mechanisms have been hypothesized to explain this hypercoagulable process such as inflammatory cytokine storm, platelet activation, endothelial dysfunction, and stasis for a long time. The purpose of this narrative review is to provide an overview of the current knowledge on the pathogenic mechanisms of coagulopathy that may characterize COVID-19 infection and inform on new areas of research. New vascular therapeutic strategies are also reviewed.

Sonothrombolysis with an acoustic net-assisted boiling histotripsy: A proof-of-concept study

Whilst sonothrombolysis is a promising and noninvasive ultrasound technique for treating blood clots, bleeding caused by thrombolytic agents used for dissolving clots and potential obstruction of blood flow by detached clots (i.e., embolus) are the major limitations of the current approach. In the present study, a new sonothrombolysis method is proposed for treating embolus without the use of thrombolytic drugs. Our proposed method involves (a) generating a spatially localised acoustic radiation force in a blood vessel against the blood flow to trap moving blood clots (i.e., generation of an acoustic net), (b) producing acoustic cavitation to mechanically destroy the trapped embolus, and (c) acoustically monitoring the trapping and mechanical fractionation processes. Three different ultrasound transducers with different purposes were employed in the proposed method: (1) 1-MHz dual focused ultrasound (dFUS) transducers for capturing moving blood clots, (2) a 2-MHz High Intensity Focused Ultrasound (HIFU) source for fractionating blood clots and (3) a passive acoustic emission detector with broad bandwidth (10 kHz to 20 MHz) for receiving and analysing acoustic waves scattered from a trapped embolus and acoustic cavitation. To demonstrate the feasibility of the proposed method, in vitro experiments with an optically transparent blood vessel-mimicking phantom filled with a blood mimicking fluid and a blood clot (1.2 to 5 mm in diameter) were performed with varying the dFUS and HIFU exposure conditions under various flow conditions (from 1.77 to 6.19 cm/s). A high-speed camera was used to observe the production of acoustic fields, acoustic cavitation formation and blood clot fragmentation within a blood vessel by the proposed method. Numerical simulations of acoustic and temperature fields generated under a given exposure condition were also conducted to further interpret experimental results on the proposed sonothrombolysis. Our results clearly showed that fringe pattern-like acoustic pressure fields (fringe width of 1 mm) produced in a blood vessel by the dFUS captured an embolus (1.2 to 5 mm in diameter) at the flow velocity up to 6.19 cm/s. This was likely to be due to the greater magnitude of the dFUS-induced acoustic radiation force exerted on an embolus in the opposite direction to the flow in a blood vessel than that of the drag force produced by the flow. The acoustically trapped embolus was then mechanically destructed into small pieces of debris (18 to 60 μm sized residual fragments) by the HIFU-induced strong cavitation without damaging the blood vessel walls. We also observed that acoustic emissions emitted from a blood clot captured by the dFUS and cavitation produced by the HIFU were clearly distinguished in the frequency domain. Taken together, these results can suggest that our proposed sonothrombolysis method could be used as a promising tool for treating thrombosis and embolism through capturing and destroying blood clots effectively.

EFFECTS OF SARS COVID-19 POSITIVITY STATUS ON VENOUS THROMBOSIS AND PULMONARY EMBOLISM RATES IN TRAUMA PATIENTS

ABSTRACT

Introduction : COVID-19-induced coagulopathy (CIC) can increase the risk of thromboembolism without underlying clotting disorders, even when compared with other respiratory viruses. Trauma has a known association with hypercoagulability. Trauma patients with concurrent COVID-19 infection potentially have an even greater risk of thrombotic events. The purpose of this study was to evaluate venous thromboembolism (VTE) rates in trauma patients with COVID-19. Methods : This study reviewed all adult patients (≥18 years of age) admitted to the Trauma Service from April through November 2020 for a minimum of 48 hours. Patients were grouped based off COVID-19 status and compared for inpatient VTE chemoprophylaxis regimen, thrombotic complications defined as deep vein thrombosis, pulmonary embolism, myocardial infarction, and cerebrovascular accident, intensive care unit (ICU) length of stay, hospital length of stay, and mortality. Results : A total of 2,907 patients were reviewed and grouped into COVID-19-positive (n = 110) and COVID-19-negative (n = 2,797) groups. There was no difference in terms of receiving deep vein thrombosis chemoprophylaxis or type, but a longer time to initiation in the positive group ( P = 0.0012). VTE occurred in 5 (4.55%) positive and 60 (2.15%) negative patients without a significant difference between the groups, as well as no difference in type of VTE observed. Mortality was higher ( P = 0.009) in the positive group (10.91%). Positive patients had longer median ICU LOS ( P = 0.0012) and total LOS ( P < 0.001). Conclusion : There were no increased rates of VTE complications between COVID-19-positive and -negative trauma patients, despite a longer time to initiation of chemoprophylaxis in the COVID-19-positive group. COVID-19-positive patients had increased ICU LOS, total LOS, and mortality, which are likely due to multifactorial causes but primarily related to their underlying COVID-19 infection.

Targeted Blood Plasma Proteomics and Hemostasis Assessment of Post COVID-19 Patients with Acute Myocardial Infarction

The molecular mechanisms underlying cardiovascular complications after the SARS-CoV-2 infection remain unknown. The goal of our study was to analyze the features of blood coagulation, platelet aggregation, and plasma proteomics in COVID-19 convalescents with AMI. The study included 66 AMI patients and 58 healthy volunteers. The groups were divided according to the anti-N IgG levels (AMI post-COVID (n = 44), AMI control (n = 22), control post-COVID (n = 31), and control (n = 27)). All participants underwent rotational thromboelastometry, thrombodynamics, impedance aggregometry, and blood plasma proteomics analysis. Both AMI groups of patients demonstrated higher values of clot growth rates, thrombus size and density, as well as the elevated levels of components of the complement system, proteins modifying the state of endothelium, acute-phase and procoagulant proteins. In comparison with AMI control, AMI post-COVID patients demonstrated decreased levels of proteins connected to inflammation and hemostasis (lipopolysaccharide-binding protein, C4b-binding protein alpha-chain, plasma protease C1 inhibitor, fibrinogen beta-chain, vitamin K-dependent protein S), and altered correlations between inflammation and fibrinolysis. A new finding is that AMI post-COVID patients opposite the AMI control group, are characterized by a less noticeable growth of acute-phase proteins and hemostatic markers that could be explained by prolonged immune system alteration after COVID-19.

Investigation of factors affecting COVID-19 pancreatic injury: a single-center, retrospective study

Pancreatic injury is considered an organ-related complication in patients with coronavirus disease 2019 (COVID-19). However, it is unclear whether COVID-19 status affects pancreatic injury. This retrospective study aimed to determine whether COVID-19 affects the occurrence of pancreatic injuries. Consecutive patients diagnosed with sepsis admitted to the ICU between March 2020 and September 2021 were included. The primary endpoint was a pancreatic injury, which was defined as amylase or lipase levels > 3 times the upper limit of the normal range. Among the 177 patients included in the analysis, 40 (23%) were COVID-19 patients, and 54 (31%) had pancreatic injuries. Of these three patients, acute pancreatitis was diagnosed based on computed tomography. The pancreatic injury was significantly more common among COVID-19 patients (75 vs. 18%, p < 0.001). Multivariate analysis showed that COVID-19 and steroid use were independent risk factors for pancreatic injury (Odds Ratio (OR) 4.79 [95% confidence interval (CI) 1.48-15.5], p = 0.009; OR 4.02 [95% CI 1.42-11.4], p = 0.009). This study revealed that the proportion of pancreatic injury in septic patients with COVID-19 was significantly higher than in those without COVID-19. It may be difficult to diagnose pancreatitis based on amylase and lipase levels in COVID-19 patients.

Retroperitoneal and abdominal bleeding in anticoagulated COVID-19 hospitalized patients: Case series and brief literature review

BACKGROUND

Hospitalized and severely ill coronavirus disease 2019 (COVID-19) patients necessitate prophylactic or therapeutic anticoagulation to minimize the risk of thrombosis at different sites. Life-threatening bleeding complications include spontaneous iliopsoas hematoma, peritoneal bleeding, and extra-abdominal manifestations such as intracranial hemorrhage.

CASE SUMMARY

Bleeding in the abdominal wall results in less severe complications than seen with iliopsoas hematoma or peritoneal bleeding. In our case series of 9 patients, we present retroperitoneal and abdominal bleeding complications following anticoagulation in hospitalized COVID-19 patients with severe acute respiratory syndrome coronavirus 2 pneumonia. Contrast-enhanced computed tomography (CE-CT) is the best imaging modality for assessing hematoma secondary to anticoagulation and determines the therapeutic approach, whether interventional, surgical, or conservative management.

CONCLUSION

We present the role of CE-CT for rapid and precise localization of the bleeding site and prognostic counseling. Finally, we provide a brief review of the literature.

Effectiveness of thromboprophylaxis with low molecular weight heparin in critically ill patients with COVID-19. An observational prospective, multicenter study

INTRODUCTION

COVID-19 induces coagulopathy associated with an increase of thromboembolic events. Due to the lack of agreement on recommendations for thromboprophylactic management, the aim of this study was to study the dosages of LMWH used in critically ill COVID-19 patients assessing the effect on their outcome.

METHODS

We evaluated data of the Reg-COVID19. According to LMWH dose two groups were analyzed: prophylaxis and treatment. Primary outcome was the relationship of LMWH dosage with mortality. Secondary outcomes included the incidence of thrombotic and bleeding events, length of ICU stay, invasive mechanical ventilation, and thrombotic and inflammatory parameters.

RESULTS

Data of 720 patients were analyzed, 258 in the prophylaxis group and 462 in the treatment group. C Reactive Protein, invasive mechanical ventilation, tocilizumab and corticosteroid treatments were related with the choice of LMWH dose. Hemorrhagic events (66/720, 9.2%) and thrombotic complications (69/720, 9.6%) were similar in both groups (p = .819 and p = .265), as was the time course of the thrombotic events, earlier than hemorrhagic ones (9 [3-18] and 12 [6-19] days respectively). Mortality was lower in prophylaxis group (25.2% versus 35.1%), but once an inverse probability weighting model was applied, we found no effect of LMWH dose.

CONCLUSION

We found no benefit or harm with the administration of therapeutic or prophylactic LMWH dose in COVID19 critically ill patients. With a similar rate of hemorrhagic or thrombotic events, the LMWH dose had no influence on mortality. More studies are needed to determine the optimal thromboprophylaxis protocol for critically ill patients.

[Effectiveness of thromboprophylaxis with low molecular weight heparin in critically ill patients with COVID-19. An observational prospective, multicenter study]

Introduction

COVID-19 induces coagulopathy associated with an increase of thromboembolic events. Due to the lack of agreement on recommendations for thromboprophylactic management, the aim of this study was to study the dosages of LMWH used in critically ill COVID-19 patients assessing the effect on their outcome.

Metohds

We evaluated data of the Reg-COVID19. According to LMWH dose two groups were analyzed: prophylaxis and treatment. Primary outcome was the relationship of LMWH dosage with mortality. Secondary outcomes included the incidence of thrombotic and bleeding events, length of ICU stay, invasive mechanical ventilation, and thrombotic and inflammatory parameters.

Results

Data of 720 patients were analyzed, 258 in the prophylaxis group and 462 in the treatment group. C Reactive Protein, invasive mechanical ventilation, tocilizumab and corticosteroid treatments were related with the choice of LMWH dose. Hemorrhagic events (66/720, 9.2%) and thrombotic complications (69/720, 9.6%) were similar in both groups (P=.819 and P=.265), as was the time course of the thrombotic events, earlier than hemorrhagic ones (9 [3-18] and 12 [6-19] days respectively). Mortality was lower in prophylaxis group (25.2% versus 35.1%), but once an inverse probability weighting model was applied, we found no effect of LMWH dose.

Conclusion

We found no benefit or harm with the administration of therapeutic or prophylactic LMWH dose in COVID19 critically ill patients. With a similar rate of hemorrhagic or thrombotic events, the LMWH dose had no influence on mortality. More studies are needed to determine the optimal thromboprophylaxis protocol for critically ill patients.

Time Course of Coagulopathy Evaluated with Rotational Thromboelastometry in Patients with Severe Coronavirus Disease 2019

Objectives Coronavirus disease 2019 (COVID-19) reportedly causes thromboembolic complications due to coagulopathy with hypercoagulability and a hypofibrinolytic state. We evaluated the time-course of coagulopathy in patients with severe COVID-19 from admission to discharge from our intensive-care unit (ICU). Methods We conducted a retrospective study of adults with severe COVID-19 admitted to our ICU between January 20, 2021, and March 31, 2022. We obtained clinical information, laboratory data, and rotational thromboelastometry (ROTEM) parameters at admission and discharge. Results Fifteen patients were included. Fibrinogen and D-dimer values did not change significantly but were above the normal ranges at admission and discharge. Regarding ROTEM parameters, the maximum clot firmness in fibrinogen function (FIBTEM), a marker of hypercoagulability, did not change significantly but was above the normal range at admission and discharge [median (interquartile range), admission vs. discharge: 31 (25-34) mm vs. 31 (27-32) mm, p=0.589]. The maximum lysis at 60 minutes in the extrinsic coagulation pathway (EXTEM) and intrinsic coagulation pathway (INTEM), as markers of the fibrinolytic function, were both significantly lower at discharge than at admission [median (interquartile range), admission vs. discharge: EXTEM, 3 (2-4) vs. 1 (0-2), p=0.011; INTEM, 3 (1-6) vs. 1 (0-2), p=0.008]. Conclusion This study revealed a persistent hypercoagulable state at ICU discharge and a worse hypofibrinolytic state at discharge than at admission. These results may contribute to a better understanding of coagulopathies in the acute to subacute phases of severe COVID-19.

Risk of thromboembolic events in non-hospitalized COVID-19 patients: A systematic review

The risk of thromboembolism in non-hospitalized COVID-19 patients remains uncertain and was assessed in this review to better weigh benefits vs. risks of prophylactic anticoagulation in this population. A search was performed through three databases: Medline, Embase, and Cochrane Library until 2022. Self-controlled case series, case-control and cohort studies were included, and findings summarized narratively. Meta-analyses for risk of thromboembolism including deep vein thrombosis (DVT), pulmonary embolism (PE), and myocardial infarction (MI) between COVID-19 and non-COVID-19 non-hospitalized patients were conducted. Frequency, incidence rate ratio (IRR), and risk ratio (RR) of stroke were used to assess risk in non-hospitalized COVID-19 patients considering the lack of studies to conduct a meta-analysis. Ten studies met inclusion criteria characterized by adult non-hospitalized COVID-19 patients. Risk of bias was relatively low. Risk of DVT (RR: 1.98 with 95% CI: 1.03-3.83) and PE (OR: 6.72 with 95% CI: 4.81-9.39 and RR: 4.44 with 95% CI: 1.98-9.99) increased in non-hospitalized COVID-19 patients compared to controls. Risk of MI (OR: 1.91 with 95% CI: 0.89-4.09) is possibly increased in non-hospitalized COVID-19 patients with moderate certainty when compared to controls. A trend in favor of stroke was documented in the first week following infection. Our meta-analyses support the increase in risk of DVT and PE, and likely increase of MI, in non-hospitalized COVID-19 patients. The risk of stroke appears significant in the first week following infection but drops to insignificance two weeks later. More studies are needed to establish evidence-based recommendations for prophylactic anticoagulation therapy in non-hospitalized COVID-19 patients.

Computational modeling of hypercoagulability in COVID-19

Coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has infected more than 100 million people worldwide and claimed millions of lives. While the leading cause of mortality in COVID-19 patients is the hypoxic respiratory failure from acute respiratory distress syndrome, there is accumulating evidence that shows excessive coagulation also increases the fatalities in COVID-19. Thus, there is a pressing demand to understand the association between COVID-19-induced hypercoagulability and the extent of formation of undesired blood clots. Mathematical modeling of coagulation has been used as an important tool to identify novel reaction mechanisms and to identify targets for new drugs. Here, we employ the coagulation factor data of COVID-19 patients reported from published studies as inputs for two mathematical models of coagulation to identify how the concentrations of coagulation factors change in these patients. Our simulation results show that while the levels of many of the abnormal coagulation factors measured in COVID-19 patients promote the generation of thrombin and fibrin, two key components of blood clots, the increased level of fibrinogen and then the reduced level of antithrombin are the factors most responsible for boosting the level of fibrin and thrombin, respectively. Altogether, our study demonstrates the potential of mathematical modeling to identify coagulation factors responsible for the increased clot formation in COVID-19 patients where clinical data is scarce.

The prevalence of deep vein thrombosis and associated risk factors among patients with COVID-19 in the North of Iran

Aim: We aimed to investigate the associated risk factors of deep vein thrombosis (DVT) among COVID-19 patients. Materials & methods: In this cross-sectional study the demographical data and clinical characteristics of 382 COVID-19 patients were collected and analyzed. Results: The DVT was observed in 53 patients (14.1%). The rate of death was significantly associated with the incidence of DVT, 48.1 versus 32.2% in non-DVT cases; p = 0.034). Also, BMI (p = 0.0001), renal failure (p = 0.001), lower-limb edema (p = 0.0001) and intubation (p = 0.004) were associated with the risk of DVT. Conclusion: COVID-19 patients with a higher BMI, renal failure, lower-limb edema and need for intubation were at a higher risk of DVT.

Post-discharge Thromboembolic Events in COVID-19 Patients: A Review on the Necessity for Prophylaxis

Coronavirus disease 2019 (COVID-19) affects the respiratory system of patients and is characterized by pneumonia with hypoxemia. Hospitalized patients and particularly those admitted to intensive care unit (ICU) may encounter a cascade of coagulopathies, which may lead to macrovessel thrombotic events such as pulmonary embolism (PE), deep vein thrombosis (DVT), or arterial thromboembolism (ATE). These events can result in serious life-threatening diseases including cerebrovascular stroke and myocardial infarction. Despite all available information about the incidence, prevention, and treatment of venous thromboembolism (VTE) among hospitalized patients, few data are available on the incidence of both symptomatic and subclinical VTE after discharge. Therefore, there is no precise suggestion or guideline for prophylaxis against VTE in post-discharge period, and some controversies exist over the current guidelines. In the present study, we aimed to review and summarize available literature upon incidence, prevention, diagnosis, and therapeutic approaches for VTE in COVID-19 patients. Also, the pathogenic mechanisms of VTE in infected individuals with COVID-19 were discussed.

Thromboembolic and bleeding events in ICU patients with COVID-19: A nationwide, observational study

BACKGROUND

Intensive care unit (ICU) patients with Coronavirus disease 2019 (COVID-19) have an increased risk of thromboembolic complications. We describe the occurrence of thromboembolic and bleeding events in all ICU patients with COVID-19 in Denmark during the first and second waves of the pandemic.

METHODS

This was a sub-study of the Danish Intensive Care Covid database, in which all patients with SARS-CoV-2 admitted to Danish ICUs from 10th March 2020 to 30th June 2021 were included. We registered coagulation variables at admission, and all thromboembolic and bleeding events, and the use of heparins during ICU stay. Variables associated with thrombosis and bleeding and any association with 90-day mortality were estimated using Cox regression analyses.

RESULTS

We included 1369 patients in this sub-study; 158 (12%, 95% confidence interval 10-13) had a thromboembolic event in ICU and 309 (23%, 20-25) had a bleeding event, among whom 81 patients (6%, 4.8-7.3) had major bleeding. We found that mechanical ventilation and increased D-dimer were associated with thrombosis and mechanical ventilation, low platelet count and presence of haematological malignancy were associated with bleeding. Most patients (76%) received increased doses of thromboprophylaxis during their ICU stay. Thromboembolic events were not associated with mortality in adjusted analysis (hazard ratio 1.35 [0.91-2.01, p = .14], whereas bleeding events were 1.55 [1.18-2.05, p = .002]).

CONCLUSIONS

Both thromboembolic and bleeding events frequently occurred in ICU patients with COVID-19. Based on these data, it is not apparent that increased doses of thromboprophylaxis were beneficial.

COVID-19-Induced Phlegmasia Cerulea Dolens

A 44-year-old male with a history of deep venous thrombosis (DVT) and pulmonary embolism (PE) with the inferior vena cava (IVC) filter in place and peripheral vascular disease (PVD) status post lower extremity vascular stenting presented from a COVID-19 rehabilitation center with bilateral phlegmasia cerulea dolens and no palpable popliteal or dorsalis pedis pulses, at risk for venous gangrene and loss of limbs. The patient was anticoagulated and taken emergently to the operating room for vascular surgery where thrombolysis with alteplase and mechanical thrombectomy were performed. Bilateral thrombolysis infusion catheters were placed for two days. The patient had a return of arterial signals in the feet and decreasing clot burden. The patient is expected to make a full recovery.

Population pharmacokinetics of nadroparin for thromboprophylaxis in COVID-19 intensive care unit patients

AIMS

Nadroparin is administered to COVID-19 intensive care unit (ICU) patients as thromboprophylaxis. Despite existing population pharmacokinetic (PK) models for nadroparin in literature, the population PK of nadroparin in COVID-19 ICU patients is unknown. Moreover, optimal dosing regimens achieving anti-Xa target levels (0.3-0.7 IU/mL) are unknown. Therefore, a population PK analysis was conducted to investigate different dosing regimens of nadroparin in COVID-19 ICU patients.

METHODS

Anti-Xa levels (n = 280) from COVID-19 ICU patients (n = 65) receiving twice daily (BID) 5700 IU of subcutaneous nadroparin were collected to perform a population PK analysis with NONMEM v7.4.1. Using Monte Carlo simulations (n = 1000), predefined dosing regimens were evaluated.

RESULTS

A 1-compartment model with an absorption compartment adequately described the measured anti-Xa levels with interindividual variability estimated for clearance (CL). Inflammation parameters C-reactive protein, D-dimer and estimated glomerular filtration rate based on the Chronic Kidney Disease Epidemiology Collaboration equation allowed to explain the interindividual variability of CL. Moreover, CL was decreased in patients receiving corticosteroids (22.5%) and vasopressors (25.1%). Monte Carlo simulations demonstrated that 5700 IU BID was the most optimal dosing regimen of the simulated regimens for achieving prespecified steady-state t = 4 h anti-Xa levels with 56.7% on target (0.3-0.7 IU/mL).

CONCLUSION

In our study, clearance of nadroparin is associated with an increase in inflammation parameters, use of corticosteroids, vasopression and renal clearance in critically ill patients. Furthermore, of the simulated regimens, targeted anti-Xa levels were most adequately achieved with a dosing regimen of 5700 IU BID. Future studies are needed to elucidate the underlying mechanisms of found covariate relationships.

Assessment and Monitoring of Coagulation in Patients with COVID-19: A Review of Current Literature

Coagulation abnormalities are common in patients with COVID-19 and associated with high morbidity and mortality. It became a daily challenge to navigate through these abnormal laboratory findings and deliver the best possible treatment to the patients. The unique character of COVID-19-induced coagulopathy necessitates not only a dynamic follow-up of the patients in terms of hemostatic findings but also the introduction of new diagnostic methods to determine the overall function of the coagulation system in real time. After the recognition of the high risk of thromboembolism in COVID-19, several professional societies published their recommendations regarding anticoagulation in patients with COVID-19. This review summarizes common hemostatic findings in COVID-19 patients and presents the societal recommendations regarding the use of coagulation laboratory findings in clinical decision-making. Although several studies have investigated coagulation parameters in patients with COVID-19, the methodological shortcomings of published studies as well as the differences in employed anticoagulation regimens that have changed over time, depending on national and international guidelines, limit the applicability of these findings in other clinical settings. Accordingly, evidence-based recommendations for diagnostics during acute COVID-19 infection are still lacking. Future studies should verify the role of coagulation parameters as well as viscoelastic methods in the management of patients with COVID-19.

Platelet in thrombo-inflammation: Unraveling new therapeutic targets

In the broad range of human diseases, thrombo-inflammation appears as a clinical manifestation. Clinically, it is well characterized in context of superficial thrombophlebitis that is recognized as thrombosis and inflammation of superficial veins. However, it is more hazardous when developed in the microvasculature of injured/inflamed/infected tissues and organs. Several diseases like sepsis and ischemia-reperfusion can cause formation of microvascular thrombosis subsequently leading to thrombo-inflammation. Thrombo-inflammation can also occur in cases of antiphospholipid syndrome, preeclampsia, sickle cell disease, bacterial and viral infection. One of the major contributors to thrombo-inflammation is the loss of normal anti-thrombotic and anti-inflammatory potential of the endothelial cells of vasculature. This manifest itself in the form of dysregulation of the coagulation pathway and complement system, pathologic platelet activation, and increased recruitment of leukocyte within the microvasculature. The role of platelets in hemostasis and formation of thrombi under pathologic and non-pathologic conditions is well established. Platelets are anucleate cells known for their essential role in primary hemostasis and the coagulation pathway. In recent years, studies provide strong evidence for the critical involvement of platelets in inflammatory processes like acute ischemic stroke, and viral infections like Coronavirus disease 2019 (COVID-19). This has encouraged the researchers to investigate the contribution of platelets in the pathology of various thrombo-inflammatory diseases. The inhibition of platelet surface receptors or their intracellular signaling which mediate initial platelet activation and adhesion might prove to be suitable targets in thrombo-inflammatory disorders. Thus, the present review summarizes the concept and mechanism of platelet signaling and briefly discuss their role in sterile and non-sterile thrombo-inflammation, with the emphasis on role of platelets in COVID-19 induced thrombo-inflammation. The aim of this review is to summarize the recent developments in deciphering the role of the platelets in thrombo-inflammation and discuss their potential as pharmaceutical targets.

Anticoagulation failure in pulmonary thromboembolism in COVID-19 pneumonia despite prolonged anticoagulation: A case series

Introduction

Moderate to severely ill patients diagnosed with Coronavirus disease 2019 (COVID-19) pneumonia develop a series of complications and less frequently, we might witness cases of Pulmonary Thromboembolism (PE)-refractory to the standard treatment with Low Molecular Weight Heparin (LMWH). The aim of this case series is to report the presentation and management of pulmonary thromboembolism secondary to COVID-19 pneumonia.

Method

We report a case series of seven cases aged 40–70 who were presented in Dhulikhel Hospital with COVID-19 symptoms in different stages. The case details were extracted from their medical reports of the hospital. The written informed ethical consents were obtained from all the cases and their voluntary participation was assured.

Outcome

The cases in the case series admitted with COVID-19 pneumonia, after diagnostic investigation (Chest x-ray, HRCT, CTPA) were suggestive of COVID-19 Pneumonia with ARDS and pulmonary thromboembolism. The cases received rivaroxaban, a newer anticoagulant-15 mg twice daily for 21 days and after discharge, they were asked to continue once daily doses for 9 weeks. Significant improvement was witnessed, with the presence of additional intervention including rehabilitative chest exercises.

Conclusion

Pulmonary thromboembolism secondary to COVID-19 pneumonia is a life-threatening condition. Rivaroxaban is seen to be very effective in the management of this condition when an anticoagulation failure occurs even after the therapeutic dose of low molecular weight heparin. Future studies may require more scientific investigations to prevent complications even in the early stages of COVID-19.

Prospects for the Use of Marine Sulfated Fucose-Rich Polysaccharides in Treatment and Prevention of COVID-19 and Post-COVID-19 Syndrome

Symptoms of the new coronavirus infection that appeared in 2019 (COVID-19) range from low fever and fatigue to acute pneumonia and multiple organ failure. The clinical picture of COVID-19 is heterogeneous and involves most physiological systems; therefore, drugs with a wide spectrum of mechanism of action are required. The choice of the treatment strategy for post-COVID-19 syndrome is still a challenge to be resolved. Polysaccharides with a high fucose content derived from seaweed and marine animals can form the basis for the subsequent development of promising agents for the treatment of COVID-19 and post-COVID-19 syndrome. This class of biopolymers is characterized by a variety of biological activities, including antiviral, antithrombotic, anticoagulant, hemo-stimulating, anti-inflammatory and immune-regulatory. Low molecular weight derivatives of these polysaccharides, as well as synthetic oligosaccharides with a sufficient amount and sulfation type may be considered as the most promising compounds due to their better bioavailability, which undoubtedly increases their therapeutic potential.

Effect of stimulated platelets in COVID-19 thrombosis: Role of alpha7 nicotinic acetylcholine receptor

Since early 2020, SARS-CoV-2-induced infection resulted in global pandemics with high morbidity, especially in the adult population. COVID-19 is a highly prothrombotic condition associated with subsequent multiorgan failure and lethal outcomes. The exact mechanism of the prothrombotic state is not well understood and might be multifactorial. Nevertheless, platelets are attributed to play a crucial role in COVID-19-associated thrombosis. To date, platelets' role was defined primarily in thrombosis and homeostasis. Currently, more focus has been set on their part in inflammation and immunity. Moreover, their ability to release various soluble factors under activation as well as internalize and degrade specific pathogens has been highly addressed in viral research. This review article will discuss platelet role in COVID-19-associated thrombosis and their role in the cholinergic anti-inflammatory pathway. Multiple studies confirmed that platelets display a hyperactivated phenotype in COVID-19 patients. Critically ill patients demonstrate increased platelet activation markers such as P-selectin, PF4, or serotonin. In addition, platelets contain acetylcholine and express α7 nicotinic acetylcholine receptors (α7nAchR). Thus, acetylcholine can be released under activation, and α7nAchR can be stimulated in an autocrine manner and support platelet function. α7 receptor is one of the most important mediators of the anti-inflammatory properties as it is associated with humoral and intrinsic immunity and was demonstrated to contribute to better outcomes in COVID-19 patients when under stimulation. Hematopoietic α7nAchR deficiency increases platelet activation and, in experimental studies, α7nAchR stimulation can diminish the pro-inflammatory state and modulate platelet reactiveness via increased levels of NO. NO has been described to inhibit platelet adhesion, activation, and aggregation. In addition, acetylcholine has been demonstrated to decrease platelet aggregation possibly by blocking the e p-38 pathway. SARS-CoV-2 proteins have been found to be similar to neurotoxins which can bind to nAChR and prevent the action of acetylcholine. Concluding, the platelet role in COVID-19 thrombotic events could be explained by their active function in the cholinergic anti-inflammatory pathway.

Understanding COVID-19-associated coagulopathy

COVID-19-associated coagulopathy (CAC) is a life-threatening complication of SARS-CoV-2 infection. However, the underlying cellular and molecular mechanisms driving this condition are unclear. Evidence supports the concept that CAC involves complex interactions between the innate immune response, the coagulation and fibrinolytic pathways, and the vascular endothelium, resulting in a procoagulant condition. Understanding of the pathogenesis of this condition at the genomic, molecular and cellular levels is needed in order to mitigate thrombosis formation in at-risk patients. In this Perspective, we categorize our current understanding of CAC into three main pathological mechanisms: first, vascular endothelial cell dysfunction; second, a hyper-inflammatory immune response; and last, hypercoagulability. Furthermore, we pose key questions and identify research gaps that need to be addressed to better understand CAC, facilitate improved diagnostics and aid in therapeutic development. Finally, we consider the suitability of different animal models to study CAC.

Efficacy and Safety of Tinzaparin in Prophylactic, Intermediate and Therapeutic Doses in Non-Critically Ill Patients Hospitalized with COVID-19: The PROTHROMCOVID Randomized Controlled Trial

Hospitalized patients with COVID-19 are at increased risk of thrombosis, acute respiratory distress syndrome and death. The optimal dosage of thromboprophylaxis is unknown. The aim was to evaluate the efficacy and safety of tinzaparin in prophylactic, intermediate, and therapeutic doses in non-critical patients admitted for COVID-19 pneumonia. PROTHROMCOVID is a randomized, unblinded, controlled, multicenter trial enrolling non-critical, hospitalized adult patients with COVID-19 pneumonia. Patients were randomized to prophylactic (4500 IU), intermediate (100 IU/kg), or therapeutic (175 IU/kg) groups. All tinzaparin doses were administered once daily during hospitalization, followed by 7 days of prophylactic tinzaparin at discharge. The primary efficacy outcome was a composite endpoint of symptomatic systemic thrombotic events, need for invasive or non-invasive mechanical ventilation, or death within 30 days. The main safety outcome was major bleeding at 30 days. Of the 311 subjects randomized, 300 were included in the prespecified interim analysis (mean [SD] age, 56.7 [14.6] years; males, 182 [60.7%]). The composite endpoint at 30 days from randomization occurred in 58 patients (19.3%) of the total population; 19 (17.1 %) in the prophylactic group, 20 (22.1%) in the intermediate group, and 19 (18.5%) in the therapeutic dose group (p = 0.72). No major bleeding event was reported; non-major bleeding was observed in 3.7% of patients, with no intergroup differences. Due to these results and the futility analysis, the trial was stopped. In non-critically ill COVID-19 patients, intermediate or full-dose tinzaparin compared to standard prophylactic doses did not appear to affect the risk of thrombotic event, non-invasive ventilation, or mechanical ventilation or death. Trial RegistrationClinicalTrials.gov Identifier (NCT04730856). Edura-CT registration number: 2020-004279-42.

Retinal microvascular signs in COVID-19

BACKGROUND/AIMS

To explore if retinal findings are associated with COVID-19 infection.

METHODS

In this prospective cross-sectional study, we recruited participants positive for COVID-19 by nasopharyngeal swab, with no medical history. Subjects underwent retinal imaging with an automated imaging device (3D OCT-1 Maestro, Topcon, Tokyo, Japan) to obtain colour fundus photographs (CFP) and optical coherence tomographic (OCT) scans of the macula. Data on personal biodata, medical history and vital signs were collected from electronic medical records.

RESULTS

108 patients were recruited. Mean age was 36.0±5.4 years. 41 (38.0%) had symptoms of acute respiratory infection (ARI) at presentation. Of 216 eyes, 25 (11.6%) had retinal signs-eight (3.7%) with microhaemorrhages, six (2.8%) with retinal vascular tortuosity and two (0.93%) with cotton wool spots (CWS). 11 eyes (5.1%) had hyper-reflective plaques in the ganglion cell-inner plexiform layer layer on OCT, of which two also had retinal signs visible on CFP (CWS and microhaemorrhage, respectively). There was no significant difference in the prevalence of retinal signs in symptomatic versus asymptomatic patients (12 (15.0%) vs 13 (9.6%), p=0.227). Patients with retinal signs were significantly more likely to have transiently elevated blood pressure than those without (p=0.03).

CONCLUSION

One in nine had retinal microvascular signs on ocular imaging. These signs were observed even in asymptomatic patients with normal vital signs. These retinal microvascular signs may be related to underlying cardiovascular and thrombotic alternations associated with COVID-19 infection.

SARS-CoV-2 and the central nervous system: Emerging insights into hemorrhage-associated neurological consequences and therapeutic considerations

Coronavirus disease 2019 (COVID-19), caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) continues to impact our lives by causing widespread illness and death and poses a threat due to the possibility of emerging strains. SARS-CoV-2 targets angiotensin-converting enzyme 2 (ACE2) before entering vital organs of the body, including the brain. Studies have shown systemic inflammation, cellular senescence, and viral toxicity-mediated multi-organ failure occur during infectious periods. However, prognostic investigations suggest that both acute and long-term neurological complications, including predisposition to irreversible neurodegenerative diseases, can be a serious concern for COVID-19 survivors, especially the elderly population. As emerging studies reveal sites of SARS-CoV-2 infection in different parts of the brain, potential causes of chronic lesions including cerebral and deep-brain microbleeds and the likelihood of developing stroke-like pathologies increases, with critical long-term consequences, particularly for individuals with neuropathological and/or age-associated comorbid conditions. Our recent studies linking the blood degradation products to genome instability, leading to cellular senescence and ferroptosis, raise the possibility of similar neurovascular events as a result of SARS-CoV-2 infection. In this review, we discuss the neuropathological consequences of SARS-CoV-2 infection in COVID survivors, focusing on possible hemorrhagic damage in brain cells, its association to aging, and the future directions in developing mechanism-guided therapeutic strategies.

Management of acute aortoiliac arterial thrombosis in patients with the novel coronavirus disease 2019: A case series and systematic review of the literature

Objectives

Venous thrombosis has been widely described in the setting of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection; however, arterial thrombosis has rarely been reported. This study aims to assess the incidence, risk factors, interventions, and outcomes of acute aortoiliac arterial thrombosis in patients with active SARS-CoV-2 infections.

Methods

We present seven SARS-CoV-2-positive patients from our institution who acutely developed thrombi in the aortoiliac arterial system (7/2020-1/2021). A systematic review of the literature on aortoiliac arterial thrombosis in patients with SARS-CoV-2 infections in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was also performed. The available data from all reported cases in the literature and at our institution were analyzed.

Results

Thirty published articles and journal correspondences, including 52 patients, were reviewed and analyzed in addition to our institution's 7 cases. In total, 59 SARS-CoV-2-positive patients were found to have acute aortoiliac thrombosis. The abdominal aorta was the most frequent location for the development of a thrombus. Baseline demographics and medical comorbidities were not significantly different between the symptomatic and asymptomatic cohorts. Seventy-one percent of patients were symptomatic (lower limb ischemia: 75.0%, renal infarction: 20.0%, stroke: 12.5%, mesenteric ischemia: 10.0%). All patients with thrombus involving the ascending aorta, aortic bifurcation, or iliac artery developed thromboembolic or ischemic complications. All patients received systemic anticoagulation. Fifty-three percent of all patients were managed medically. Ninety-four percent of the asymptomatic patients were managed medically. One asymptomatic patient underwent endovascular aspiration of a mobile thrombus. Three (23.1%) deaths occurred in the asymptomatic cohort from hypoxic respiratory failure. Fourteen (36.8%) deaths occurred in the symptomatic cohort. The in-hospital mortality rate was 33.3% overall and 43.8% for patients with thrombi involving more than one aortoiliac segment.

Conclusions

The presence of thrombi in the aortoiliac arterial system appears to be a poor prognostic indicator for patients with active SARS-CoV-2 infections. Medical management of patients with asymptomatic aortoiliac thrombi may be considered. The presence of thrombi involving the ascending aorta, aortic bifurcation, or iliac artery may warrant consideration for operative intervention due to the risk for thromboembolic or ischemic complications. Further study is needed to fully delineate the risk factors, optimal treatment, and outcomes of arterial thrombosis in the setting of SARS-CoV-2 infection.

The RALE Score Versus the CT Severity Score in Invasively Ventilated COVID-19 Patients—A Retrospective Study Comparing Their Prognostic Capacities

Background: Quantitative radiological scores for the extent and severity of pulmonary infiltrates based on chest radiography (CXR) and computed tomography (CT) scan are increasingly used in critically ill invasively ventilated patients. This study aimed to determine and compare the prognostic capacity of the Radiographic Assessment of Lung Edema (RALE) score and the chest CT Severity Score (CTSS) in a cohort of invasively ventilated patients with acute respiratory distress syndrome (ARDS) due to COVID-19. Methods: Two-center retrospective observational study, including consecutive invasively ventilated COVID-19 patients. Trained scorers calculated the RALE score of first available CXR and the CTSS of the first available CT scan. The primary outcome was ICU mortality; secondary outcomes were duration of ventilation in survivors, length of stay in ICU, and hospital-, 28-, and 90-day mortality. Prognostic accuracy for ICU death was expressed using odds ratios and Area Under the Receiver Operating Characteristic curves (AUROC). Results: A total of 82 patients were enrolled. The median RALE score (22 [15–37] vs. 26 [20–39]; p = 0.34) and the median CTSS (18 [16–21] vs. 21 [18–23]; p = 0.022) were both lower in ICU survivors compared to ICU non-survivors, although only the difference in CTSS reached statistical significance. While no association was observed between ICU mortality and RALE score (OR 1.35 [95%CI 0.64–2.84]; p = 0.417; AUC 0.50 [0.44–0.56], this was noticed with the CTSS (OR, 2.31 [1.22–4.38]; p = 0.010) although with poor prognostic capacity (AUC 0.64 [0.57–0.69]). The correlation between the RALE score and CTSS was weak (r² = 0.075; p = 0.012). Conclusions: Despite poor prognostic capacity, only CTSS was associated with ICU mortality in our cohort of COVID-19 patients.

Effects of statins on outcomes in Hispanic patients with COVID-19

The Hispanic population is regarded among those who are at greater risk of adverse prognoses due to higher rates of diabetes and obesity in the USA during the COVID-19 pandemic. Statin medications are speculated to help treat the infection by decreasing inflammation caused by COVID-19. In this retrospective, observational study, outcomes of statin use were assessed among Hispanic patients with COVID-19 by screening all patients hospitalized between March, 2020 and March, 2021 at a tertiary care hospital in El Paso, Texas, resulting in a total of 1039 patients. The patients were categorized into a group of either being on statins or not. The considered outcomes were mechanical ventilation, intensive care unit (ICU) hospitalization, oxygen supplementation at discharge, hospital length of stay, and mortality. Patients receiving statins were observed to be older with more comorbidities. In the propensity-scores adjusted analysis, no association was found between statin use and: mortality (adjusted risk ratio (aRR)=0.96, p=0.754), mechanical ventilation (aRR=0.91, p=0.503), ICU transfer (aRR=0.96, p=0.395), and O₂ supplementation at discharge (aRR=1.03, p=0.729). These outcomes were also evaluated in patients who had myocardial infarction and stroke with COVID-19. Among these patients, association was found between statin use and: a reduced risk of mortality (aRR=0.61, p=0.005), mechanical ventilation (aRR=0.53, p=0.012) and ICU transfers (aRR=0.81, p=0.005). These results may not give us a reason to start patients on statins for the specific treatment of COVID-19, but it may be sufficient evidence to suggest statins should not be discontinued during hospitalization due to COVID-19.

Association of COVID-19 vs Influenza With Risk of Arterial and Venous Thrombotic Events Among Hospitalized Patients

IMPORTANCE

The incidence of arterial thromboembolism and venous thromboembolism in persons with COVID-19 remains unclear.

OBJECTIVE

To measure the 90-day risk of arterial thromboembolism and venous thromboembolism in patients hospitalized with COVID-19 before or during COVID-19 vaccine availability vs patients hospitalized with influenza.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective cohort study of 41 443 patients hospitalized with COVID-19 before vaccine availability (April-November 2020), 44 194 patients hospitalized with COVID-19 during vaccine availability (December 2020-May 2021), and 8269 patients hospitalized with influenza (October 2018-April 2019) in the US Food and Drug Administration Sentinel System (data from 2 national health insurers and 4 regional integrated health systems).

EXPOSURES

COVID-19 or influenza (identified by hospital diagnosis or nucleic acid test).

MAIN OUTCOMES AND MEASURES

Hospital diagnosis of arterial thromboembolism (acute myocardial infarction or ischemic stroke) and venous thromboembolism (deep vein thrombosis or pulmonary embolism) within 90 days. Outcomes were ascertained through July 2019 for patients with influenza and through August 2021 for patients with COVID-19. Propensity scores with fine stratification were developed to account for differences between the influenza and COVID-19 cohorts. Weighted Cox regression was used to estimate the adjusted hazard ratios (HRs) for outcomes during each COVID-19 vaccine availability period vs the influenza period.

RESULTS

A total of 85 637 patients with COVID-19 (mean age, 72 [SD, 13.0] years; 50.5% were male) and 8269 with influenza (mean age, 72 [SD, 13.3] years; 45.0% were male) were included. The 90-day absolute risk of arterial thromboembolism was 14.4% (95% CI, 13.6%-15.2%) in patients with influenza vs 15.8% (95% CI, 15.5%-16.2%) in patients with COVID-19 before vaccine availability (risk difference, 1.4% [95% CI, 1.0%-2.3%]) and 16.3% (95% CI, 16.0%-16.6%) in patients with COVID-19 during vaccine availability (risk difference, 1.9% [95% CI, 1.1%-2.7%]). Compared with patients with influenza, the risk of arterial thromboembolism was not significantly higher among patients with COVID-19 before vaccine availability (adjusted HR, 1.04 [95% CI, 0.97-1.11]) or during vaccine availability (adjusted HR, 1.07 [95% CI, 1.00-1.14]). The 90-day absolute risk of venous thromboembolism was 5.3% (95% CI, 4.9%-5.8%) in patients with influenza vs 9.5% (95% CI, 9.2%-9.7%) in patients with COVID-19 before vaccine availability (risk difference, 4.1% [95% CI, 3.6%-4.7%]) and 10.9% (95% CI, 10.6%-11.1%) in patients with COVID-19 during vaccine availability (risk difference, 5.5% [95% CI, 5.0%-6.1%]). Compared with patients with influenza, the risk of venous thromboembolism was significantly higher among patients with COVID-19 before vaccine availability (adjusted HR, 1.60 [95% CI, 1.43-1.79]) and during vaccine availability (adjusted HR, 1.89 [95% CI, 1.68-2.12]).

CONCLUSIONS AND RELEVANCE

Based on data from a US public health surveillance system, hospitalization with COVID-19 before and during vaccine availability, vs hospitalization with influenza in 2018-2019, was significantly associated with a higher risk of venous thromboembolism within 90 days, but there was no significant difference in the risk of arterial thromboembolism within 90 days.

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.

Role of Acute Thrombosis in Coronavirus Disease 2019

Patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are prone to venous, cerebrovascular, and coronary thrombi, particularly those with severe coronavirus disease 2019 (COVID-19). The pathogenesis is multifactorial and likely involves proinflammatory cascades, development of coagulopathy, and neutrophil extracellular traps, although further investigations are needed. Elevated levels of D-dimers are common in patients with COVID-19 and cannot be used in isolation to predict venous thromboembolism in people with SARS-CoV-2. If given early in hospital admission, therapeutic-dose heparin improves clinical outcomes in patients with moderate COVID-19. To date, antithrombotics have not improved outcomes in patients with severe COVID-19.

Venous and arterial thrombosis in COVID-19: An updated narrative review

Hospitalized patients with coronavirus disease 2019 (COVID-19), particularly those admitted to the intensive care unit (ICU) are at high risk of morbidity and mortality. Several observational studies have described hemostatic derangements and thrombotic complications in patients with COVID-19. The aim of this review article is to summarize the current evidence on pathologic findings, pathophysiology, coagulation and hemostatic abnormalities, D-dimer's role in prognostication epidemiology and risk factors of thrombotic complications, and the role of prophylactic and therapeutic anticoagulation in patients with COVID-19. While existing evidence is limited in quality, COVID-19 appears to increase micro-and macro-vascular thrombosis rates in hospitalized and critically ill patients, which may contribute to the burden of disease. D-dimer can be used for risk stratification of hospitalized patients, but its role to guide anticoagulation therapy remains unclear. Evidence of higher quality is needed to address the role of therapeutic anticoagulation or high-intensity venous thromboembolism prophylaxis in COVID-19 patients. TAKE-HOME POINTS.

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.

Post-COVID-19 hematologic complications: a systematic review

INTRODUCTION

COVID-19 crisis continues around the world. Some patients developed complications after the disease, which have been reported in limited studies. The aim of this study is to comprehensively assess the post-COVID hematologic complications in patients.

AREAS COVERED

We searched PubMed, Scopus and Google Scholar between January 2020 and August 2021 using related keywords. Evaluation of the articles was performed by two independent researchers. The extracted data included number of patients, age, type of hematological complication, duration of follow-up, response to treatment and prognosis.

EXPERT OPINION

Sixty five articles reported post-COVID hematologic complications. The most frequent hematologic complication in COVID-19 patients is thromboembolic events, which often occur in two forms: deep vein thrombosis (DVT) and pulmonary emboli (PE). In a group of patients after the diagnosis of COVID-19, a significant decrease in platelets was observed, which was attributed to the ITP induced by COVID-19. Hemolytic anemia and aplastic anemia have also been reported rarely in patients. Finally, post-COVID hematologic complications appear to go beyond thromboembolic events. Although these complications have been reported rarely, searching for methods to identify susceptible patients and prevent these complications could be the subject of future research.

Therapeutic anticoagulation to prevent thrombosis, coagulopathy, and mortality in severe COVID‐19: The Swiss COVID‐HEP randomized clinical trial

Background

Hospitalized patients with COVID‐19 suffered initially from high rates of venous thromboembolism (VTE), with possible associations between therapeutic anticoagulation and better clinical outcomes in observational studies.

Objective

To test whether therapeutic anticoagulation improves clinical outcomes in severe COVID‐19.

Patients/Methods

In this multicenter, open‐label, randomized controlled trial, we recruited acutely ill medical COVID‐19 patients with D‐dimer >1000 ng/ml or critically ill COVID‐19 patients in four Swiss hospitals, from April 2020 until June 2021, with a 30‐day follow‐up. Participants were randomized to in‐hospital therapeutic anticoagulation versus low‐dose anticoagulation in acutely ill participants/intermediate‐dose anticoagulation in critically ill participants, with enoxaparin or unfractionated heparins. The primary outcome was a centrally adjudicated composite of 30‐day all‐cause mortality, VTE, arterial thrombosis, and disseminated intravascular coagulopathy (DIC), with screening for proximal deep vein thrombosis.

Results

Among 159 participants, 55.3% were critically ill and 94.3% received corticosteroids. Before study inclusion, pulmonary embolism had been excluded in 71.7%. The primary outcome occurred in 4/79 participants randomized to therapeutic anticoagulation and 4/80 to low/intermediate anticoagulation (5.4% vs. 5.0%; risk difference +0.4%; adjusted hazard ratio 0.76, 95% confidence interval 0.18–3.21), including three deaths in each group. All primary outcomes and major bleeding (n = 3) occurred in critically ill participants. There was no asymptomatic proximal deep vein thrombosis and no difference in major bleeding.

Conclusions

Among patients with severe COVID‐19 treated with corticosteroids and with exclusion of pulmonary embolism at hospital admission for most, risks of mortality, thrombotic outcomes, and DIC were low at 30 days. The lack of benefit of therapeutic anticoagulation was too imprecise for definite conclusions.

Immuno-Thrombotic Complications of COVID-19: Implications for Timing of Surgery and Anticoagulation

Early in the coronavirus disease 2019 (COVID-19) pandemic, global governing bodies prioritized transmissibility-based precautions and hospital capacity as the foundation for delay of elective procedures. As elective surgical volumes increased, convalescent COVID-19 patients faced increased postoperative morbidity and mortality and clinicians had limited evidence for stratifying individual risk in this population. Clear evidence now demonstrates that those recovering from COVID-19 have increased postoperative morbidity and mortality. These data-in conjunction with the recent American Society of Anesthesiologists guidelines-offer the evidence necessary to expand the early pandemic guidelines and guide the surgeon's preoperative risk assessment. Here, we argue elective surgeries should still be delayed on a personalized basis to maximize postoperative outcomes. We outline a framework for stratifying the individual COVID-19 patient's fitness for surgery based on the symptoms and severity of acute or convalescent COVID-19 illness, coagulopathy assessment, and acuity of the surgical procedure. Although the most common manifestation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is COVID-19 pneumonitis, every system in the body is potentially afflicted by an endotheliitis. This endothelial derangement most often manifests as a hypercoagulable state on admission with associated occult and symptomatic venous and arterial thromboembolisms. The delicate balance between hyper and hypocoagulable states is defined by the local immune-thrombotic crosstalk that results commonly in a hemostatic derangement known as fibrinolytic shutdown. In tandem, the hemostatic derangements that occur during acute COVID-19 infection affect not only the timing of surgical procedures, but also the incidence of postoperative hemostatic complications related to COVID-19-associated coagulopathy (CAC). Traditional methods of thromboprophylaxis and treatment of thromboses after surgery require a tailored approach guided by an understanding of the pathophysiologic underpinnings of the COVID-19 patient. Likewise, a prolonged period of risk for developing hemostatic complications following hospitalization due to COVID-19 has resulted in guidelines from differing societies that recommend varying periods of delay following SARS-CoV-2 infection. In conclusion, we propose the perioperative, personalized assessment of COVID-19 patients' CAC using viscoelastic hemostatic assays and fluorescent microclot analysis.

Immunouniverse of SARS-CoV-2

SARS-CoV-2 virus has become a global health problem that has caused millions of deaths worldwide. The infection can present with multiple clinical features ranging from asymptomatic or mildly symptomatic patients to patients with severe or critical illness that can even lead to death. Although the immune system plays an important role in pathogen control, SARS-CoV-2 can drive dysregulation of this response and trigger severe immunopathology. Exploring the mechanisms of the immune response involved in host defense against SARS-CoV-2 allows us to understand its immunopathogenesis and possibly detect features that can be used as potential therapies to eliminate the virus. The main objective of this review on SARS-CoV-2 is to highlight the interaction between the virus and the immune response. We explore the function and action of the immune system, the expression of molecules at the site of infection that cause hyperinflammation and hypercoagulation disorders, the factors leading to the development of pneumonia and subsequent severe acute respiratory distress syndrome which is the leading cause of death in patients with COVID-19.

Insights into Cardiovascular Defects and Cardiac Epigenome in the Context of COVID-19

Although few in number, studies on epigenome of the heart of COVID-19 patients show that epigenetic signatures such as DNA methylation are significantly altered, leading to changes in expression of several genes. It contributes to pathogenic cardiac phenotypes of COVID-19, e.g., low heart rate, myocardial edema, and myofibrillar disarray. DNA methylation studies reveal changes which likely contribute to cardiac disease through unknown mechanisms. The incidence of severe COVID-19 disease, including hospitalization, requiring respiratory support, morbidity, and mortality, is disproportionately higher in individuals with co-morbidities. This poses unprecedented strains on the global healthcare system. While their underlying conditions make patients more susceptible to severe COVID-19 disease, strained healthcare systems, lack of adequate support, or sedentary lifestyles from ongoing lockdowns have proved detrimental to their underlying health conditions, thus pushing them to severe risk of congenital heart disease (CHD) itself. Prophylactic vaccines against COVID-19 have ushered new hope for CHD. A common connection between COVID-19 and CHD is SARS-CoV-2’s host receptor ACE2, because ACE2 regulates and protects organs, including the heart, in various ways. ACE2 is a common therapeutic target against cardiovascular disease and COVID-19 which damages organs. Hence, this review explores the above regarding CHDs, cardiovascular damage, and cardiac epigenetics, in COVID-19 patients.

Fibrin Strands Will Grow from Soluble Fibrin and Hang Up in an In Vitro Microcirculatory Viscoelastic Model: Is This a Major Cause of COVID-19 Associated Coagulopathy?

Viscoelastic testing (VET) by both TEG and ROTEM has demonstrated hypercoagulability early in corona virus disease 2019 (COVID-19) associated coagulopathy (CAC). Additional VET studies demonstrated fibrinolytic shutdown late in a majority of severely ill COVID-19 patients with an associated elevation of d-dimer. Elevated d-dimer confirms that coagulation, followed by fibrinolysis, has occurred. These findings imply that, during CAC, three enzymes—thrombin, Factor XIIIa and plasmin—must have acted in sequence. However, limitations in standard VET analyses preclude exploration of the earliest phases of clot induction, as well as clot formation and clot dissolution in flowing blood. Herein, we describe a novel method illuminating aspects of this unexplored area. In addition, we created an in vitro blood flow model in which the interactions of thrombin, Factor XIII and plasmin with fibrinogen can be studied, allowing the determination of soluble fibrin (SF), the highly unstable form of fibrin that precedes the appearance of a visible clot. This model allows the determination of the SF level at which fibrin microclots begin to form.