Modified IMPROVE VTE Risk Score and Elevated D-Dimer Identify a High Venous Thromboembolism Risk in Acutely Ill Medical Population for Extended Thromboprophylaxis

Construction and validation of risk prediction models for pulmonary embolism in hospitalized patients based on different machine learning methods

Objective

This study aims to apply different machine learning (ML) methods to construct risk prediction models for pulmonary embolism (PE) in hospitalized patients, and to evaluate and compare the predictive efficacy and clinical benefit of each model.

Methods

We conducted a retrospective study involving 332 participants (172 PE positive cases and 160 PE negative cases) recruited from Guangdong Medical University. Participants were randomly divided into a training group (70%) and a validation group (30%). Baseline data were analyzed using univariate analysis, and potential independent risk factors associated with PE were further identified through univariate and multivariate logistic regression analysis. Six ML models, namely Logistic Regression (LR), Decision Tree (DT), Random Forest (RF), Naive Bayes (NB), Support Vector Machine (SVM), and AdaBoost were developed. The predictive efficacy of each model was compared using the receiver operating characteristic (ROC) curve analysis and the area under the curve (AUC). Clinical benefit was assessed using decision curve analysis (DCA).

Results

Logistic regression analysis identified lower extremity deep venous thrombosis, elevated D-dimer, shortened activated partial prothrombin time, and increased red blood cell distribution width as potential independent risk factors for PE. Among the six ML models, the RF model achieved the highest AUC of 0.778. Additionally, DCA consistently indicated that the RF model offered the greatest clinical benefit.

Conclusion

This study developed six ML models, with the RF model exhibiting the highest predictive efficacy and clinical benefit in the identification and prediction of PE occurrence in hospitalized patients.

Validation of the International Medical Prevention Registry on Venous Thromboembolism (IMPROVE) risk scores for venous thromboembolism and bleeding in an independent population

Background

Multiple guidelines recommend assessment of bleeding and venous thromboembolism (VTE) risk in adult medical inpatients to inform prevention strategies. There is no agreed-upon method for VTE and bleeding risk assessment.

Objectives

To validate the International Medical Prevention Registry on Venous Thromboembolism (IMPROVE) VTE and bleeding risk scores in an independent population.

Methods

In this retrospective study, we calculated the IMPROVE VTE and bleeding risk scores in medical inpatients admitted between 2010 and 2019 at the University of Vermont Medical Center (UVMMC). Patients were followed for in-hospital bleeding events while hospitalized and VTE events while hospitalized and for 3 months after discharge. We assessed calibration of the risk models by comparing the observed incidence of events in the UVMMC and IMPROVE populations across the published risk categories. We also assessed performance of the IMPROVE risk factors after refitting the models in the UVMMC population. Discrimination was assessed using the area under the receiver operating characteristic curve (AUC).

Results

VTE occurred in 270 (1.1%) of 23,873 admissions, with 92 (34%) occurring during admission, and bleeding occurred in 712 (4.7%) of 15,240 admissions. When the IMPROVE-VTE risk factors were refitted to the UVMMC data, the AUC was 0.64. When the IMPROVE bleeding risk factors were refitted to the UVMMC data, the AUC was 0.67. The IMPROVE-VTE score tended to overestimate risk at higher scores, and the IMPROVE bleeding score underestimated risk at lower scores and overestimated risk at higher scores.

Conclusion

While the refitted IMPROVE VTE and bleeding risk scores had reasonable model fit, the scores were poorly calibrated and did not reliably identify or differentiate patients at risk for VTE and bleeding. Different methods are needed for risk assessment of medical inpatients for VTE and bleeding risk.

System-Wide Thromboprophylaxis Interventions for Hospitalized Patients at Risk of Venous Thromboembolism: Focus on Cross-Platform Clinical Decision Support

Thromboprophylaxis of hospitalized patients at risk of venous thromboembolism (VTE) presents challenges owing to patient heterogeneity and lack of adoption of evidence-based methods. Intuitive practices for thromboprophylaxis have resulted in many patients being inappropriately prophylaxed. We conducted a narrative review summarizing system-wide thromboprophylaxis interventions in hospitalized patients. Multiple interventions for thromboprophylaxis have been tested, including multifaceted approaches such as national VTE prevention programs with audits, pre-printed order entry, passive alerts (either human or electronic), and more recently, the use of active clinical decision support (CDS) tools incorporated into electronic health records (EHRs). Multifaceted health-system and order entry interventions have shown mixed results in their ability to increase appropriate thromboprophylaxis and reduce VTE unless mandated through a national VTE prevention program, though the latter approach is potentially costly and effort- and time-dependent. Studies utilizing passive human or electronic alerts have also shown mixed results in increasing appropriate thromboprophylaxis and reducing VTE. Recently, a universal cloud-based and EHR-agnostic CDS VTE tool incorporating a validated VTE risk score revealed high adoption and effectiveness in increasing appropriate thromboprophylaxis and reducing major thromboembolism. Active CDS tools hold promise in improving appropriate thromboprophylaxis, especially with further refinement and widespread implementation within various EHRs and clinical workflows.

Dissecting the rationale for thromboprophylaxis in challenging surgical cases

Pulmonary embolism (PE) is a leading preventable cause of death in surgical patients, and rates of fatal PE are increasing. Individual assessment, to balance the risks of thrombosis and bleeding, is the key to providing appropriate prophylaxis. The risk assessment process includes use of evidence-based guidelines, literature published since the latest guidelines, large registries, and risk scoring systems together with clinical experience and judgment. Risk assessment is a dynamic process and needs to be updated both during the hospital stay and just prior to discharge since clinical events may change the level of risk. The final assessment may identify patients who require ongoing anticoagulant prophylaxis after discharge. The Caprini risk score is widely used in surgical patients and is a composite of the number of risk factors and their relative weights. The Caprini risk score set point for risk levels requiring anticoagulant prophylaxis varies depending on the type of surgical procedure, surgical population, and number of risk factors. Mandatory implementation of evidence-based care pathways is helpful in lowering PE-related mortality. This review presents several challenging cases, emphasizing the importance of employing all available assessment tools, including dynamic assessment of risk during hospitalization. Finally, the limitations of evidence-based guidelines in complex scenarios and the need to employ all available tools to properly protect very high-risk patients are emphasized.

Integrating Clinical Decision Support Into Electronic Health Record Systems Using a Novel Platform (EvidencePoint): Developmental Study

BACKGROUND

Through our work, we have demonstrated how clinical decision support (CDS) tools integrated into the electronic health record (EHR) assist providers in adopting evidence-based practices. This requires confronting technical challenges that result from relying on the EHR as the foundation for tool development; for example, the individual CDS tools need to be built independently for each different EHR.

OBJECTIVE

The objective of our research was to build and implement an EHR-agnostic platform for integrating CDS tools, which would remove the technical constraints inherent in relying on the EHR as the foundation and enable a single set of CDS tools that can work with any EHR.

METHODS

We developed EvidencePoint, a novel, cloud-based, EHR-agnostic CDS platform, and we will describe the development of EvidencePoint and the deployment of its initial CDS tools, which include EHR-integrated applications for clinical use cases such as prediction of hospitalization survival for patients with COVID-19, venous thromboembolism prophylaxis, and pulmonary embolism diagnosis.

RESULTS

The results below highlight the adoption of the CDS tools, the International Medical Prevention Registry on Venous Thromboembolism-D-Dimer, the Wells' criteria, and the Northwell COVID-19 Survival (NOCOS), following development, usability testing, and implementation. The International Medical Prevention Registry on Venous Thromboembolism-D-Dimer CDS was used in 5249 patients at the 2 clinical intervention sites. The intervention group tool adoption was 77.8% (4083/5249 possible uses). For the NOCOS tool, which was designed to assist with triaging patients with COVID-19 for hospital admission in the event of constrained hospital resources, the worst-case resourcing scenario never materialized and triaging was never required. As a result, the NOCOS tool was not frequently used, though the EvidencePoint platform's flexibility and customizability enabled the tool to be developed and deployed rapidly under the emergency conditions of the pandemic. Adoption rates for the Wells' criteria tool will be reported in a future publication.

CONCLUSIONS

The EvidencePoint system successfully demonstrated that a flexible, user-friendly platform for hosting CDS tools outside of a specific EHR is feasible. The forthcoming results of our outcomes analyses will demonstrate the adoption rate of EvidencePoint tools as well as the impact of behavioral economics "nudges" on the adoption rate. Due to the EHR-agnostic nature of EvidencePoint, the development process for additional forms of CDS will be simpler than traditional and cumbersome IT integration approaches and will benefit from the capabilities provided by the core system of EvidencePoint.

Universal EHRs Clinical Decision Support for Thromboprophylaxis in Medical Inpatients: A Cluster Randomized Trial

Background

Thromboprophylaxis for medically ill patients during hospitalization and postdischarge remains underutilized. Clinical decision support (CDS) may address this need if embedded within workflow, interchangeable among electronic health records (EHRs), and anchored on a validated model.

Objectives

The purpose of this study was to assess the clinical impact of a universal EHR-integrated CDS tool based on the International Medical Prevention Registry on Venous Thromboembolism plus D-Dimer venous thromboembolism model.

Methods

This was a cluster randomized trial of 4 tertiary academic hospitals from December 21, 2020 to January 21, 2022. Inpatients over age 60 with key medical illnesses were eligible. We embedded CDS at admission and discharge. Hospitals were randomized to intervention (CDS; n = 2) vs usual care (n = 2) groups. The primary outcome was rate of appropriate thromboprophylaxis. Secondary outcomes included venous, arterial, and total thromboembolism, major bleeding, and all-cause mortality through 30 days postdischarge.

Results

After exclusions, 10,699 of 19,823 patients were analyzed. Intervention group tool adoption was 77.8%. Appropriate thromboprophylaxis was increased at intervention hospitals, both inpatient (80.1% vs 72.5%, OR: 1.52, 95% CI: 1.39-1.67) and at discharge (13.6% vs 7.5%, OR: 1.93, 95% CI: 1.60-2.33). There were fewer venous (2.7% vs 3.3%, OR: 0.80, 95% CI: 0.64-1.00), arterial (0.25% vs 0.70%, OR: 0.35, 95% CI: 0.19-0.67), and total thromboembolisms (2.9% vs 4.0%, OR: 0.71, 95% CI: 0.58-0.88) at intervention hospitals. Major bleeding was rare and did not differ between groups. Mortality was higher at intervention hospitals (9.1% vs 7.0%, OR: 1.32, 95% CI: 1.15-1.53).

Conclusions

EHR-embedded CDS increased appropriate thromboprophylaxis and reduced thromboembolism without increasing major bleeding in medically ill inpatients. Mortality was higher at intervention hospitals.

Anticoagulant therapy in COVID-19: A narrative review

Coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), can manifest itself in several ways, including coagulopathy and thrombosis. These complications can be the first and sometimes only manifestations of SARS-CoV-2 infection and can occur early or late in the course of the disease. However, these symptoms are more prevalent in hospitalized patients with venous thromboembolism, particularly those admitted to intensive care units. Moreover, various forms of arterial and venous thrombosis, or micro- or macro-vasculature embolisms, have been reported during the current pandemic. They have led to harmful consequences, such as neurological and cardiac events, nearly all resulting from the hypercoagulable state caused by this viral infection. The severe hypercoagulability observed in patients with COVID-19 accounts for most cases of the disease that become critical. Therefore, anticoagulants seem to be one of the most vital therapeutics for treating this potentially life-threatening condition. In the current paper, we present a thorough review of the pathophysiology of COVID-19-induced hypercoagulable state and the use of anticoagulants to treat SARS-CoV-2 infections in different patient groups, as well as their pros and cons.

A systematic review on post-discharge venous thromboembolism prophylaxis in patients with COVID-19

BACKGROUND

Coronavirus disease of 2019 (COVID-19) is associated with venous thromboembolism (VTE), not only during hospitalization but also after discharge, raising concerns about anticoagulant (AC) use for post-discharge COVID-19 patients. We aimed to systematically review the current literature on the possible benefits or risks regarding extended thromboprophylaxis.

MAIN BODY

We searched related databases from December 1, 2019, to October 6, 2022, including studies on the necessity, duration, and selection of the ideal AC regarding extended thromboprophylaxis for post-discharge COVID-19 patients. The screening of the selected databases led to 18 studies and 19 reviews and guidelines. Studies included 52,927 hospitalized COVID-19 patients, with 19.25% receiving extended thromboprophylaxis. VTE events ranging from 0 to 8.19% (median of 0.7%) occurred in a median follow-up of 49.5 days. All included studies and guidelines, except four studies, recommended post-discharge prophylaxis after an individual risk assessment indicating high thrombotic and low bleeding risk. Studies used risk assessment models (RAMs), clinical evaluation, and laboratory data to identify COVID-19 patients with a high risk of VTE. IMPROVE-DD was the most recommended RAM. Direct oral anticoagulants (DOACs) and low molecular weight heparins (LMWHs) were the most used AC classes.

CONCLUSIONS

Post-discharge prophylaxis for COVID-19 patients is recommended after an individual assessment. The IMPROVE-DD model can help predict VTE risk. After distinguishing patients who need post-discharge AC therapy, DOACs for 30-35 days and LMWHs for 40-45 days can be the drug of choice. Further studies, particularly the results of the ongoing randomized controlled trials (RCTs), are required. Also, to properly handle such patients, every physician should consider lifestyle modification in addition to pharmacological treatment for post-discharge VTE prophylaxis.

The effect of rivaroxaban on biomarkers in blood and plasma: a review of preclinical and clinical evidence

Rivaroxaban is a direct, oral factor Xa inhibitor that is used for the prevention and treatment of various thromboembolic disorders. Several preclinical and clinical studies have utilized specific molecules as biomarkers to investigate the potential role of rivaroxaban beyond its anticoagulant activity and across a range of biological processes. The aim of this review is to summarize the existing evidence regarding the use of blood-based biomarkers to characterize the effects of rivaroxaban on coagulation and other pathways, including platelet activation, inflammation and endothelial effects. After a literature search using PubMed, almost 100 preclinical and clinical studies were identified that investigated the effects of rivaroxaban using molecular biomarkers. In agreement with the preclinical data, clinical studies reported a trend for reduction in the blood concentrations of D-dimers, thrombin-antithrombin complex and prothrombin fragment 1 + 2 following treatment with rivaroxaban in both healthy individuals and those with various chronic conditions. Preclinical and also some clinical studies have also reported a potential impact of rivaroxaban on the concentrations of platelet activation biomarkers (von Willebrand factor, P-selectin and thrombomodulin), endothelial activation biomarkers (matrix metalloproteinase-9, intercellular adhesion molecule-1 and vascular cell adhesion molecule-1) and inflammation biomarkers (interleukin-6, tumor necrosis factor-α and monocyte chemoattractant protein-1). Based on the results of biomarker studies, molecular biomarkers can be used in addition to traditional coagulation assays to increase the understanding of the anticoagulation effects of rivaroxaban. Moreover, there is preliminary evidence to suggest that rivaroxaban may have an impact on the biological pathways of platelet activation, endothelial activation and inflammation; however, owing to paucity of clinical data to investigate the trends reported in preclinical studies, further investigation is required to clarify these observations.

To Anticoagulate or Not to Anticoagulate in COVID-19: Lessons after 2 Years

A hypercoagulable state associated with coronavirus disease 2019 (COVID-19) has been well documented and is believed to be strongly supported by a proinflammatory state. The hypercoagulable state in turn results in increased incidence of arterial and venous thromboembolism (VTE) seen in hospitalized COVID-19 when compared with hospitalized non-COVID-19 patient cohorts. Moreover, patients with arterial or VTE and COVID-19 have higher mortality compared with COVID-19 patients without arterial or VTE. Prevention of arterial or VTE thus remains an essential question in the management of COVID-19 patients, especially because of high rates of reported microvascular and macrovascular thrombosis. This has prompted multiple randomized control trials (RCTs) evaluating different anticoagulation strategies in COVID-19 patients at various stages of the disease. Herein, we review findings from RCTs in the past 2 years of antithrombotic therapy in critically ill hospitalized patients, noncritically ill hospitalized patients, patients postdischarge from the hospital, and outpatients. RCTs in critically ill patients demonstrated therapeutic dose anticoagulation does not improve outcomes and has more bleeding than prophylaxis dose anticoagulant in these patients. Trials in noncritically ill hospitalized patients showed a therapeutic dose anticoagulation with a heparin formulation might improve clinical outcomes. Anticoagulation with a direct oral anticoagulant posthospital discharge may improve outcomes, although there is a large RCT in progress. Nonhospitalized COVID-19 patients have an insufficient burden of events to be candidates for antithrombotic therapy. Anticoagulation in pregnant and lactating patients with COVID-19, as well as antiplatelet therapy for COVID-19, is also reviewed.

Derivation and External Validation of a Risk Assessment Model of Venous Thromboembolism in Hospitalized Chinese Patients

AIM

To develop and validate a risk assessment model (RAM) of venous thromboembolism (VTE) in hospitalized Chinese patients.

METHODS

We reviewed data from 300 patients with VTE and 300 non-VTE patients at Beijing Shijitan Hospital. The risk factors related to VTE were analyzed, and the VTE RAM (Shijitan (SJT) version) was developed according to the weight of each risk factor. A total of 407 patients with VTE and 533 non-VTE patients were enrolled for external validation. The sensitivity, specificity, Youden index, receiver operating curve (ROC), and area under the ROC curve (AUC) were used to evaluate the performance of VTE RAM (SJT version) compared with Caprini RAM and Padua RAM.

RESULTS

The VTE RAM (SJT version) contained six risk factors (age >60 years, lower limb edema, chronic obstructive pulmonary disease (COPD), central venous catheterization (CVC), VTE history, and D dimer). In the external validation group, for medical patients, the AUC value of SJT RAM (0.82 ± 0.03) is significantly higher than Caprini RAM (0.76 ± 0.04; P < 0.05), SJT RAM has a higher sensitivity, specificity, and Youden index than Caprini RAM (P < 0.05), which means that the SJT RAM has a much better predictive value than Caprini RAM. While SJT RAM and Padua RAM have the similar predictive value for medical patients (P > 0.05). For surgical patients, the AUC value of SJT RAM (0.72 ± 0.04) is significantly higher than the value of Padua RAM (0.66 ± 0.04; P < 0.05), SJT RAM has a higher sensitivity, specificity, and Youden index than Padua RAM (P < 0.05), which shows that the VTE RAM has better predictive value than Padua RAM. While SJT RAM and Caprini RAM have the similar predictive value for surgical patients (P > 0.05).

CONCLUSION

The SJT RAM derived from general hospitalized Chinese patients will be time-saving for physicians and has a better predictive ability for patients at risk of VTE.

Pulmonary embolism management in the emergency department: part 2

Pulmonary embolism (PE) can present with a range of severity. Prognostic risk stratification is important for efficacious and safe management. This second of two review articles discusses the management of high-, intermediate- and low-risk PE. We discuss strategies to identify patients suitable for urgent outpatient care in addition to identification of patients who would benefit from thrombolysis. We discuss specific subgroups of patients where optimal treatment differs from the usual approach and identify emerging management paradigms exploring new therapies and subgroups.

To prophylax or not, and how much and how long? Controversies in VTE prevention for medical inpatients, including COVID-19 inpatients

The field of thromboprophylaxis for acutely ill medical patients, including those hospitalized for COVID-19, is rapidly evolving both in the inpatient setting and the immediate post-hospital discharge period. Recent data reveal the importance of incorporating holistic thromboembolic outcomes that encompass both venous thromboembolism (VTE) and arterial thromboembolism, as thromboprophylaxis with low-dose direct oral anticoagulants has been shown to reduce major and fatal vascular events, especially against a background of dual pathway inhibition with aspirin. In addition, recent post hoc analyses from randomized trial data have established 5 key bleeding-risk factors that, if removed, reveal a low-bleeding- risk medically ill population and, conversely, key individual risk factors, such as advanced age, a past history of cancer or VTE, an elevated D-dimer, or the use of a validated VTE risk score-the IMPROVE VTE score using established cutoffs-to predict a high-VTE-risk medically ill population that benefits from extended postdischarge thromboprophylaxis. Last, thromboprophylaxis of a high-thrombotic-risk subset of medically ill patients, those with COVID-19, is rapidly evolving, both during hospitalization and post discharge. This article reviews 3 controversial topics in the thromboprophylaxis of hospitalized acutely ill medical patients: (1) clinical relevance of key efficacy and safety outcomes incorporated into randomized trials but not incorporated into relevant antithrombotic guidelines on the topic, (2) the use of individual risk factors or risk models of low-bleeding-risk and high-thrombotic-risk subgroups of medically ill inpatients that benefit from extended thromboprophylaxis, and (3) thromboprophylaxis of hospitalized COVID-19 patients, including extended postdischarge thromboprophylaxis.

Current and emerging drug strategies for the prevention of venous thromboembolism in acutely ill medical inpatients

INTRODUCTION

Venous thromboembolism (VTE) is a common complication in patients hospitalized for acute medical illnesses. Therefore, medical inpatients require a careful VTE and bleeding risk assessment to drive optimal strategies for VTE prevention. Low molecular weight heparin and fondaparinux have long been used for inhospital prophylaxis for patients at increased risk of VTE. The selection of patients who require post-discharge prophylaxis, and the role of direct oral anticoagulants remain debated. New molecules currently under development may contribute to improve the risk benefit of VTE prevention in this setting.

AREAS COVERED

This text summarizes the evidence on approved treatments and on other drugs for the prevention of VTE in acutely ill medical patients. The main focus is on their pharmacological proprieties, clinical efficacy and safety, and the current license approved by the FDA (Food and Drug Administration) and EMA (European Medicines Agency), giving the readers a way to compare available drugs to date. The trials presented consider both inhospital and extended prophylaxis.

EXPERT OPINION

Thanks to the potentially favorable safety profile, factor XI inhibitors may play a role in the prevention of VTE in this setting. The expert opinion section discusses pharmacological properties, prophylaxis trials, and potential clinical applications of this novel class of drugs.

The pharmacology of anticoagulant drug treatment options in COVID-19 patients: reviewing real-world evidence in clinical practice

INTRODUCTION

The optimal anticoagulation strategy for venous thromboembolism (VTE) prevention among COVID-19 patients, hospitalized or in the community setting, is still challenging and largely based on real-world evidence.

AREAS COVERED

We analyzed real-world data regarding the safety and effectiveness of anticoagulant treatment, both parenteral and oral, for VTE prevention or atrial fibrillation (AF)/VTE treatment among COVID-19 patients.

EXPERT OPINION

The efficacy of low-molecular-weight heparin (LMWH) doses for VTE prevention correlates with COVID-19 disease status. LMWH prophylactic dose may be useful in COVID-19 patients at the early stage of the disease. LMWH intermediate or therapeutic dose is recommended in COVID-19 patients with an advanced stage of the disease. COVID-19 patients on VKAs therapy for atrial fibrillation (AF) and VTE should switch to NOACs in the community setting or LMWH in the hospital setting. No definitive data on de-novo starting of NOACs or VKAs therapy for VTE prevention in COVID-19 outpatients are available. In patients at high risk discharged after hospitalization due to COVID-19, thromboprophylaxis with NOACs may be considered.

COVID-19 infection complicated with acute pulmonary embolism treated with percutaneous pulmonary artery thrombectomy: a case report

Background

Coronavirus disease 2019 (COVID-19) disease is a highly prothrombotic state. Deep vein thrombosis (DVT) and pulmonary embolism (PE) are observed with increased incidence in patients infected with the severe acute respiratory syndrome coronavirus 2 virus.

Case summary

A 57-year-old male patient with a recent COVID-19 infection complained of leg swelling shortly after his COVID ward discharge. A few days later he was hospitalized with acute massive PE and DVT of his left leg was diagnosed. In another facility, as the first line of treatment, the PE was managed with catheter-directed therapy (CDT) using thrombus defragmentation via 5F (French) Pigtail catheter and supraselective application of 40 mg alteplase. Following the procedure, in addition, 50 mg alteplase was also applied as a 1 hour systemic infusion. Despite the haemodynamic stabilization of the patient, he remained persistently symptomatic and tachycardic. Three days later—in our institution, a second computed tomography pulmoangiography revealed massive thrombotic masses mainly in the left pulmonary artery. Successful percutaneous thrombus aspiration was conducted. The procedure was uneventful with an immediate drop of systolic pulmonary artery pressure from 68 to 47 mmHg and relief of the patient’s symptoms.

Discussion

In the era of the COVID-19 pandemic, physicians have to remain vigilant of its potential thrombotic complications, the most commonly observed being DVT and PE. We demonstrated the efficacy of percutaneous thrombus aspiration in a patient with acute COVID-19-associated PE, after initial CDT with thrombus defragmentation and high-dose tissue plasminogen activator was implemented with a suboptimal result.

Extended post-discharge thromboprophylaxis in hospitalized COVID-19 patients

INTRODUCTION

Hospitalized COVID-19 patients, particularly those with high risk features, are at risk for venous and arterial thromboembolic events for approximately 30 days or more after hospital discharge. Extended post-hospital discharge thromboprophylaxis has potential to reduce this risk.

AREAS COVERED

Recent cohort, registry, and randomized trial data on the topic of extended post-discharge thromboprophylaxis in COVID-19 inpatients are reviewed, and key patient subgroups at high thrombotic risk are highlighted, with antithrombotic guidelines on the topic discussed.

EXPERT OPINION

COVID-19 inpatients with cardiovascular risk factors, advanced age, intensive care unit stay, or an IMPROVE VTE score of 4 or more or a score of 2 or 3 plus elevated D-dimers (> twice the upper limit of normal) or an IMPROVE-DD VTE score of ≥ 4 are at high thrombotic risk in the post-discharge period. These high risk patient subgroups benefit from extended post-discharge thromboprophylaxis, specifically with rivaroxaban 10mg daily for 35 days. Recent NIH and ISTH guidelines recommend or suggest this approach. Results from other clinical trials are pending.

Biomarker derived risk scores predict venous thromboembolism and major bleeding among patients with COVID-19

Background

Venous thromboembolism (VTE) risk is increased in patients with COVID‐19 infection. Understanding which patients are likely to develop VTE may inform pharmacologic VTE prophylaxis decision making. The hospital‐associated venous thromboembolism–Intermountain Risk Score (HA‐VTE IMRS) and the hospital‐associated major bleeding–Intermountain Risk Score (HA‐MB IMRS) are risk scores predictive of VTE and bleeding that were derived from only patient age and data found in the complete blood count (CBC) and basic metabolic panel (BMP).

Objectives

We assessed the HA‐VTE IMRS and HA‐MB IMRS for predictiveness of 90‐day VTE and major bleeding, respectively, among patients diagnosed with COVID‐19, and further investigated if adding D‐dimer improved these predictions. We also reported 30‐day outcomes.

Patients/Methods

We identified 5047 sequential patients with a laboratory confirmed diagnosis of COVID‐19 and a CBC and BMP between 2 days before and 7 days following the diagnosis of COVID‐19 from March 12, 2020, to February 28, 2021. We calculated the HA‐VTE IMRS and the HA‐MB IMRS for all patients. We assessed the added predictiveness of D‐dimer obtained within 48 hours of the COVID test.

Results

The HA‐VTE IMRS yielded a c‐statistic of 0.70 for predicting 90‐day VTE and adding D‐dimer improved the c‐statistic to 0.764 with the corollary sensitivity/specificity/positive/negative predictive values of 49.4%/75.7%/6.7%/97.7% and 58.8%/76.2%/10.9%/97.4%, respectively. Among hospitalized and ambulatory patients separately, the HA‐VTE IMRS performed similarly. The HA‐MB IMRS predictiveness for 90‐day major bleeding yielded a c‐statistic of 0.64.

Conclusion

The HA‐VTE IMRS and HA‐MB IMRS predict 90‐ and 30‐day VTE and major bleeding among COVID‐19 patients. Adding D‐dimer improved the predictiveness of the HA‐VTE IMRS for VTE.

Anticoagulation in COVID-19: current concepts and controversies

Rising incidence of thromboembolism secondary to COVID-19 has become a global concern, with several surveys reporting increased mortality rates. Thrombogenic potential of the SARS-CoV-2 virus has been hypothesised to originate from its ability to produce an exaggerated inflammatory response leading to endothelial dysfunction. Anticoagulants have remained the primary modality of treatment of thromboembolism for decades. However, there is no universal consensus regarding the timing, dosage and duration of anticoagulation in COVID-19 as well as need for postdischarge prophylaxis. This article seeks to review the present guidelines and recommendations as well as the ongoing trials on use of anticoagulants in COVID-19, identify discrepancies between all these, and provide a comprehensive strategy regarding usage of these drugs in the current pandemic.

Use of Anticoagulants in COVID-19: A Review

BACKGROUND

Coronavirus disease 2019 (COVID-19) is associated with elevated rates of major and fatal thrombotic events, postulated to be the result of a hypercoagulable state mediated through inflammatory and immunomodulatory mechanisms. Early observational studies showed that disease severity and elevated serum D-dimer levels can predict thrombotic risk in patients hospitalized with COVID-19 and reported an alarming phenomenon of breakthrough thrombosis despite standard-of-care prophylaxis, suggesting the need for enhanced thromboprophylactic strategies.

AREAS OF UNCERTAINTY

Data on anticoagulant agent selection, dosing, and duration for COVID-19 inpatients are now poised to inform updated professional society guidance. However, there remains limited high-quality data regarding postdischarge and especially ambulatory patients with COVID-19.

DATA SOURCES

This review includes published, peer-reviewed, observational, and randomized controlled trial data and major professional society guidance informing thrombosis prevention and treatment in patients with COVID-19.

THERAPEUTIC ADVANCES

There remains great variability in the approach to anticoagulation in COVID-19. This article will review pathogenesis of COVID-related thrombosis and the evidence guiding thromboprophylaxis particularly in inpatients, with attention to the INSPIRATION, ACTION, RAPID, HEP-COVID, and multiplatform trials. Emerging thromboprophylaxis data from the postdischarge setting (particularly the recently published MICHELLE trial), and the outpatient setting, will be examined. Finally, thrombosis treatment considerations will briefly be reviewed.

CONCLUSIONS

Substantial high-quality data support practice changes to COVID-19 thromboprophylaxis. Risk stratification by setting, disease severity, and biomarkers such as D-dimer is critical in considering choice, dose, and duration of anticoagulants.

[Anticoagulation in coronavirus disease 2019 (COVID-19): confirmed and controversial aspects]

Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is associated with a high risk of microvascular immunothrombosis as well as symptomatic and incidental thromboembolisms, predominantly in the venous system but also in the arterial system. This explains among other things the high cardiovascular morbidity and mortality of the patients. The present state of knowledge on the pathophysiology of immunothrombosis and the strategies of anticoagulation in patients with coronavirus disease 2019 (COVID-19) are summarized and illuminated in this article. According to the current guidelines moderately to severely ill patients who are being treated in hospital should receive thrombosis prophylaxis with low molecular weight or unfractionated heparin or alternatively with fondaparinux, as long as there is no clearly increased risk of bleeding. Apart from the established indications for treatment, an intensified or therapeutic dose prophylaxis should be considered very cautiously in these critically ill patients, also due to the increased bleeding complications. The routine continuation of prophylactic anticoagulation after discharge from hospital is currently not recommended.

Elucidating the Correlation of D-Dimer Levels with COVID-19 Severity: A Scoping Review

Aims. The review explores the findings of previous studies to elucidate the association between levels of D-dimer and COVID-19 severity and prognosis. In addition, we assessed the efficiency of anticoagulant therapies in reducing COVID-19 severity and improving the prognosis of the patients. Materials and Methods. A comprehensive literature review was conducted using MEDLINE/PubMed databases, Scopus, and Web of Science with the help of keywords “COVID-19,” “D-Dimer,” “Thrombosis,” “Fibrin network,” “Anticoagulant therapy,” “Inflammation,” and “disease severity.” Based on all these articles and clinical experience, a scoping review was constructed and the full texts of the articles that were retrieved were accessed. Results. A D-dimer is a complex protein molecule that is formed during plasmin-mediated degradation of the fibrin network. Thus, it serves as a marker of thrombotic activity. On the other hand, in addition to severe respiratory distress and reduction in pulmonary gas exchange, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) also triggers prothrombotic changes in the infected individuals. The levels of D-dimer have been postulated to be positively associated with the degree of disease severity among COVID-19 patients. Conclusions. It has been postulated that D-dimer could potentially be used as a biomarker to predict the prognosis and outcome of COVID-19 patients at the time of admission to hospitals and facilitate more personalized and efficient clinical management that could significantly reduce the mortality rate of such patients and allow more rapid recovery.

Predicting pulmonary embolism among hospitalized patients with machine learning algorithms

Background

Objective

Materials and Methods

Results

Conclusions

Late-onset hematological complications post COVID-19: An emerging medical problem for the hematologist

Coronavirus disease 19 (COVID‐19) is considered a multisystemic disease. Several studies have reported persistent symptoms or late‐onset complications after acute COVID‐19, including post‐COVID‐19 hematological disorders. COVID‐19‐induced coagulopathy, an immunothrombotic state, has been linked to thromboembolic and hemorrhagic events. Late‐onset thrombocytopenia related to immune system dysregulation has also been reported as a rare manifestation post COVID‐19. Close monitoring of laboratory dynamics is considered essential to identify timely abnormal values that need further investigation, providing supportive care whenever indicated. The role of hematologists is essential in terms of the multidisciplinary approach of long COVID‐19. This review summarizes all the available evidence on post‐acute COVID‐19 hematological complications.

COVID-19 and thrombotic complications-the role of anticoagulants, antiplatelets and thrombolytics

Coronavirus disease 2019 (COVID-19) is a global pandemic the world is dealing with currently. Clinical evidences suggest that the patients are predisposed to both venous and arterial thrombotic complications. This is because of severe inflammatory responses, injury to endothelium and activation of platelets leading to increased coagulation. Additionally, individuals who are already receiving antithrombotic drug therapy for various cardiovascular diseases and complications might contract the disease in which case, attention should be given to the choice and duration of the therapy besides close monitoring of biochemical blood parameters. Herein, we review the incidences of thrombotic complications and their outcomes in COVID-19 patients as reported till date, while understanding the prophylactic and therapeutic roles of anticoagulants, antiplatelets and thrombolytics in the management of this severe viral respiratory illness.

COVID-19 and coagulopathy

The SARS-CoV-2 is a new coronavirus responsible for the COVID-19 disease and has caused the pandemic worldwide. A large number of cases have overwhelmed the healthcare system worldwide. The COVID-19 infection has been associated with a heightened risk of thromboembolic complications. Various mechanisms are leading to the high thrombotic risk in COVID-19 patients such as inflammation, endotheliitis, hyperviscosity, and hypercoagulability. We searched PubMed, EMBASE, and CINAHL from January 2020 to December 2020. We used the following search terms: COVID-19, coagulopathy, and thrombosis. We reviewed the epidemiology, clinical features, mechanisms, and treatment of COVID-19-associated coagulopathy.

Asymptomatic deep vein thromboses in prolonged hospitalized COVID-19 patients

High incidence of venous thromboembolic (VTE) events in coronavirus disease 2019 (COVID-19) patients has been reported despite pharmacologic thromboprophylaxis. We performed prospective bilateral lower extremity ultrasound evaluation of prolonged hospitalized COVID-19 ward patients from our institution without clinical suspicion of deep vein thrombosis (DVT).

A total of 102 patient were included in the study. All patients were receiving pharmacologic thromboprophylaxis, the majority in intermediate or therapeutic doses. Asymptomatic DVT was detected in 26/102 (25.5%) patients: 22 had distal and four had proximal DVT, six had bilateral leg involvement. Pulmonary embolism was highly prevalent (17/70, 24.3%) but similarly grouped among patients with and without asymptomatic DVT. In total 37.2% of patients included in the study were recognized as having VTE.

Asymptomatic DVT events were more common in intensive care unit (ICU) survivors (60% in postmechanically ventilated ICU survivors, 21.2% in ward patients, 22% in high-flow oxygen treated patients; P = 0.031), in patients with higher modified International Medical Prevention Registry on Venous Thromboembolism (IMPROVE) VTE risk-score (median 3 vs. 2 points with and without DVT; P = 0.021) and higher body temperature on admission (median 38.7 °C vs. 37.7 °C with and without DVT; P = 0.001). No clear associations with Padua VTE risk score, demographic and other clinical characteristics, intensity of thromboprophylaxis, severity of other COVID-19 symptoms, degree of systemic inflammation or D‑dimers on admission were found (P > 0.05 for all analyses).

Systematic ultrasound assessment in prolonged hospitalized severe COVID-19 patients prior to hospital discharge is needed, especially in ICU survivors, to timely recognize and appropriately treat patients with asymptomatic DVT.

Anticoagulation in COVID-19: a review of current literature and guidelines

Severe acute respiratory syndrome coronavirus 2 infections are associated with greater risk of both arterial and venous thromboembolic events.Pathophysiology and Clinical implications: This has been attributed to a florid proinflammatory state resulting in microvascular dysfunction, activation of platelets and procoagulant systems as well as possible direct endothelial injury. The associated morbidity and mortality of these events has prompted much speculation and varied anticoagulation and fibrinolytic strategies based on multiple criteria including disease severity and biomarkers. No clear definitive benefit has been established with these approaches, which have frequently led to greater bleeding complications without significant mortality benefit.Overview: In this review, we outline the burden of these thromboembolic events in coronavirus disease-2019 (COVID-19) as well as the hypothesized contributory biological mechanisms. Finally, we provide a brief overview of the major clinical studies on the topic, and end with a summary of major societal guideline recommendations on anticoagulation in COVID-19.

Inflammatory Markers and Thromboembolic Risk in Patients with Non-Muscle-Invasive Bladder Cancer

Introduction: Patients with bladder cancer have a high risk of venous thrombosis that represents a key challenge for physicians in the decision-making for initiating anticoagulation therapy. Non-muscle-invasive bladder cancer (NMIBC) represents more than 70% of all diagnosed bladder malignancies; therefore, we aimed to evaluate the relationship of the neutrophil to lymphocyte ratio (NLR), lymphocyte to monocyte ratio (LMR), and risk of thrombosis by using the International Medical Prevention Registry on Venous Thromboembolism (IMPROVE) score as well as the risk of bleeding by using the IMPROVE Bleeding Risk Assessment Score in a study cohort. Material and Methods: This was a retrospective observational study involving 130 patients who met the inclusion criteria: age > 18 years, stage pTa-pT1 NMIBC. The exclusion criteria were age < 18 years; stage pT2 or higher; or a presentation of metastasis, inflammatory, liver or autoimmune diseases, or other systemic neoplasms. In order to evaluate the risk of thromboembolic events as well as those of bleeding, the IMPROVE scores were calculated for each patient. Subjects were categorized in a Low IMPROVE group (< 4 points) or a High IMPROVE group. By using uni- and multivariate regression models, we analyzed CBC-derived parameters which could be associated with a higher risk of venous thrombosis in subjects with low or high IMPROVE scores. Results: Patients with IMPROVE score greater than 4 were associated with higher NLR, LMR and lymphocyte values (p < 0.05). In a multivariate regression model, the IMPROVE score was significantly influenced by lymphocyte count (p = 0.007) as well as the NLR value (p < 0.0001). Conclusions: In our study population, subjects with NMIBC with low lymphocytes and NLR > 3 were at a higher risk of developing venous thromboembolic events, reflected by an IMPROVE score of greater than 4. The IMPROVE and IMPROVE Bleeding Risk Assessment Scores are easy to use, and, complemented with the CBC-derived lymphocyte to monocyte ratio as a prothrombotic marker, could aid in the decision of prophylactic anticoagulation therapy during admission.

American Society of Hematology living guidelines on the use of anticoagulation for thromboprophylaxis in patients with COVID-19: July 2021 update on post-discharge thromboprophylaxis

Background

COVID-19–related acute illness is associated with an increased risk of venous thromboembolism (VTE).

Objective

These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians, and other health care professionals in decisions about the use of anticoagulation for thromboprophylaxis in patients with COVID-19 who do not have confirmed or suspected VTE.

Methods

ASH formed a multidisciplinary guideline panel, including 3 patient representatives, and applied strategies to minimize potential bias from conflicts of interest. The McMaster University GRADE Centre supported the guideline development process, including performing systematic evidence reviews (up to March 2021). The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The panel used the grading of recommendations assessment, development, and evaluation (GRADE) approach to assess evidence and make recommendations, which were subject to public comment.

Results

The panel agreed on 1 additional recommendation. The panel issued a conditional recommendation against the use of outpatient anticoagulant prophylaxis in patients with COVID-19 who are discharged from the hospital and who do not have suspected or confirmed VTE or another indication for anticoagulation.

Conclusions

This recommendation was based on very low certainty in the evidence, underscoring the need for high-quality randomized controlled trials assessing the role of postdischarge thromboprophylaxis. Other key research priorities include better evidence on assessing risk of thrombosis and bleeding outcomes in patients with COVID-19 after hospital discharge.

Factors Associated With Risk of Postdischarge Thrombosis in Patients With COVID-19

IMPORTANCE

COVID-19 is associated with a high incidence of thrombotic events; however, the need for extended thromboprophylaxis after hospitalization remains unclear.

OBJECTIVE

To quantify the rate of postdischarge arterial and venous thromboembolism in patients with COVID-19, identify the factors associated with the risk of postdischarge venous thromboembolism, and evaluate the association of postdischarge anticoagulation use with venous thromboembolism incidence.

DESIGN, SETTING, AND PARTICIPANTS

This is a cohort study of adult patients hospitalized with COVID-19 confirmed by a positive SARS-CoV-2 test. Eligible patients were enrolled at 5 hospitals of the Henry Ford Health System from March 1 to November 30, 2020. Data analysis was performed from April to June 2021.

EXPOSURES

Anticoagulant therapy after discharge.

MAIN OUTCOMES AND MEASURES

New onset of symptomatic arterial and venous thromboembolic events within 90 days after discharge from the index admission for COVID-19 infection were identified using International Statistical Classification of Diseases and Related Health Problems, Tenth Revision codes.

RESULTS

In this cohort study of 2832 adult patients hospitalized with COVID-19, the mean (SD) age was 63.4 (16.7) years (IQR, 53-75 years), and 1347 patients (47.6%) were men. Thirty-six patients (1.3%) had postdischarge venous thromboembolic events (16 pulmonary embolism, 18 deep vein thrombosis, and 2 portal vein thrombosis). Fifteen (0.5%) postdischarge arterial thromboembolic events were observed (1 transient ischemic attack and 14 acute coronary syndrome). The risk of venous thromboembolism decreased with time (Mann-Kendall trend test, P < .001), with a median (IQR) time to event of 16 (7-43) days. There was no change in the risk of arterial thromboembolism with time (Mann-Kendall trend test, P = .37), with a median (IQR) time to event of 37 (10-63) days. Patients with a history of venous thromboembolism (odds ratio [OR], 3.24; 95% CI, 1.34-7.86), peak dimerized plasmin fragment D (D-dimer) level greater than 3 μg/mL (OR, 3.76; 95% CI, 1.86-7.57), and predischarge C-reactive protein level greater than 10 mg/dL (OR, 3.02; 95% CI, 1.45-6.29) were more likely to experience venous thromboembolism after discharge. Prescriptions for therapeutic anticoagulation at discharge were associated with reduced incidence of venous thromboembolism (OR, 0.18; 95% CI, 0.04-0.75; P = .02).

CONCLUSIONS AND RELEVANCE

Although extended thromboprophylaxis in unselected patients with COVID-19 is not supported, these findings suggest that postdischarge anticoagulation may be considered for high-risk patients who have a history of venous thromboembolism, peak D-dimer level greater than 3 μg/mL, and predischarge C-reactive protein level greater than 10 mg/dL, if their bleeding risk is low.

Peripheral artery disease, the 'lost syndrome' during lockdown for COVID-19: A report of three cases

The recent coronavirus disease 2019 (COVID-19) pandemic has significantly increased the burden placed on healthcare systems worldwide. This health emergency has led to changes being implemented in the organization of health institutions and has shifted the focus on pandemic management. This has led to marked changes being made in the treatment of patients without COVID-19, and has resulted in more difficult access to healthcare, with ensuing delays in diagnosis and treatment. Vascular diseases, including peripheral artery disease (PAD), require prompt treatment in the majority of cases in order to save affected limbs. Moreover, COVID-19 may result in acute arterial and venous complications, which need to be promptly recognized and treated. The present study describes three paradigmatic clinical cases of hospitalized patients, which are representative of the different forms of the 'lost syndrome' caused by either the direct effect of COVID-19 or by the effects of COVID-19 on the healthcare system and lifestyle factors. Prophylaxis against arterial and venous thrombotic events is crucial in patients with COVID-19, particularly those with a marked inflammatory state. On the other hand, the COVID-19 pandemic has diminished the access to healthcare system for patients with other chronic pathologies, with potential severe consequences for vulnerable patient groups, such as those with PAD and cardiovascular diseases. For these patients, the authors' experience over the last few months suggests that more suitable measures need to be adopted to avoid additional severe consequences on public health. In addition, it is necessary to identify pathways that will allow these patients to have rapid access to treatment with marked improvements in outcome.

The Impact of Risk-Adjusted Heparin Regimens on the Outcome of Patients with COVID-19 Infection. A Prospective Cohort Study

Background. According to recent guidelines, all hospitalized patients with COVID-19 should receive pharmacological prophylaxis for venous thromboembolism (VTE), unless there are specific contraindications. However, the optimal preventive strategy in terms of intensity of anticoagulation for these patients is not well established. Objectives. To investigate the impact of individualized regimens of enoxaparin on the development of VTE and on the risk of major bleeding complications during hospitalization in patients with COVID-19 infection. Methods. All consecutive patients admitted to the medical wards of six Italian hospitals between 15 September and 15 October 2020 with COVID-19 infection of moderate severity were administered enoxaparin in subcutaneous daily doses adjusted to the Padua Prediction Score stratification model: No heparin in patients scoring less than 4, 4000 IU daily in those scoring 4, 6000 IU in those scoring 5, and 8000 in those scoring six or more. Objective tests were performed in patients developing clinical symptoms of deep vein thrombosis and/or pulmonary embolism. Bleeding complications were defined according to the ISTH classification. Results. From the 154 eligible patients, enoxaparin was administered in all: 4000 IU in 73 patients, 6000 IU in 53, and 8000 IU in the remaining 28. During the course of hospitalization, 27 patients (17.5%) died. VTE developed in 14 of the 154 patients (9.1%; 95% CI, 4.6% to 13.6%), and was fatal in 1. Major bleeding complications developed in 35 patients (22.7%; 95% CI, 16.1% to 29.3%), and were fatal in 8. Conclusions. Despite the use of risk-adjusted doses of enoxaparin, the rate of VTE events was consistent with that reported in contemporary studies where fixed-dose low-molecular-weight heparin was used. The unexpectedly high risk of bleeding complications should induce caution in administering enoxaparin in doses higher than the conventional low ones.

Thromboembolism and Bleeding in COVID-19

Coronavirus disease 2019 (COVID-19) is characterized by a coagulation dysfunction which has different underlying mechanisms and factors. Patients with severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection have an increased risk for thromboembolic and bleeding complications. Incidences are high, and mainly consist of venous thromboembolism (VTE), which significantly contributes to morbidity and mortality in affected patients. Thromboprophylaxis is recommended in all hospitalized COVID-19 patients. Therapeutic doses of antithrombotic agents are only beneficial in noncritically ill patients, and usual care thromboprophylaxis is sufficient in critically ill patients at the ICU. Regarding screening for VTE, high quality evidence is warranted to investigate the significance of asymptomatic DVT in the ICU setting and its influence on PE and mortality.

Outpatient Management of COVID-19 Disease: A Holistic Patient-Centered Proposal Based on the Greek Experience

Novel coronavirus disease 2019 (COVID-19) is an infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become a worldwide pandemic and affected more than 227 countries or territories, resulting in more than 179 million cases with over 3.890.00 deaths, as of June 25, 2021. The Hellenic Thoracic Society (HTS) during the second wave of COVID-19 pandemic released a guidance document for the management of patients with COVID-19 in the community and in hospital setting. In this review, with guidance the HTS document, we are discussing the outpatient management of COVID-19 patients, including the preventive measures, the patients' isolation and quarantine criteria of close contacts, the severity and risk stratification, including the decisions for advanced hospitalization, and the disease management at home in patients with mild disease and after hospital discharge for those with more severe disease.

Viscoelastic testing reveals normalization of the coagulation profile 12 weeks after severe COVID-19

COVID 19 is associated with a hypercoagulable state and frequent thromboembolic complications. For how long this acquired abnormality lasts potentially requiring preventive measures, such as anticoagulation remains to be delineated. We used viscoelastic rotational thrombelastometry (ROTEM) in a single center cohort of 13 critical ill patients and performed follow up examinations three months after discharge from ICU. We found clear signs of a hypercoagulable state due to severe hypofibrinolysis and a high rate of thromboembolic complications during the phase of acute illness. Three month follow up revealed normalization of the initial coagulation abnormality and no evidence of venous thrombosis in all thirteen patients. In our cohort the coagulation profile was completely normalized three months after COVID-19. Based on these findings, discontinuation of anticoagulation can be discussed in patients with complete venous reperfusion.

Postdischarge thromboembolic outcomes and mortality of hospitalized patients with COVID-19: the CORE-19 registry

In our registry, 90-day postdischarge VTE, ATE, and ACM rates were 1.55%, 1.71%, and 4.83%, respectively.

Discharge anticoagulants, mostly prophylactic doses, were associated with 46% decrease in major thromboembolism or ACM composite end point.

Thromboembolic events, including venous thromboembolism (VTE) and arterial thromboembolism (ATE), and mortality from subclinical thrombotic events occur frequently in coronavirus disease 2019 (COVID-19) inpatients. Whether the risk extends postdischarge has been controversial. Our prospective registry included consecutive patients with COVID-19 hospitalized within our multihospital system from 1 March to 31 May 2020. We captured demographics, comorbidities, laboratory parameters, medications, postdischarge thromboprophylaxis, and 90-day outcomes. Data from electronic health records, health informatics exchange, radiology database, and telephonic follow-up were merged. Primary outcome was a composite of adjudicated VTE, ATE, and all-cause mortality (ACM). Principal safety outcome was major bleeding (MB). Among 4906 patients (53.7% male), mean age was 61.7 years. Comorbidities included hypertension (38.6%), diabetes (25.1%), obesity (18.9%), and cancer history (13.1%). Postdischarge thromboprophylaxis was prescribed in 13.2%. VTE rate was 1.55%; ATE, 1.71%; ΑCM, 4.83%; and MB, 1.73%. Composite primary outcome rate was 7.13% and significantly associated with advanced age (odds ratio [OR], 3.66; 95% CI, 2.84-4.71), prior VTE (OR, 2.99; 95% CI, 2.00-4.47), intensive care unit (ICU) stay (OR, 2.22; 95% CI, 1.78-2.93), chronic kidney disease (CKD; OR, 2.10; 95% CI, 1.47-3.0), peripheral arterial disease (OR, 2.04; 95% CI, 1.10-3.80), carotid occlusive disease (OR, 2.02; 95% CI, 1.30-3.14), IMPROVE-DD VTE score ≥4 (OR, 1.51; 95% CI, 1.06-2.14), and coronary artery disease (OR, 1.50; 95% CI, 1.04-2.17). Postdischarge anticoagulation was significantly associated with reduction in primary outcome (OR, 0.54; 95% CI, 0.47-0.81). Postdischarge VTE, ATE, and ACM occurred frequently after COVID-19 hospitalization. Advanced age, cardiovascular risk factors, CKD, IMPROVE-DD VTE score ≥4, and ICU stay increased risk. Postdischarge anticoagulation reduced risk by 46%.

Thromboembolic Complications of SARS-CoV-2 and Metabolic Derangements: Suggestions from Clinical Practice Evidence to Causative Agents

Severe Acute Respiratory Syndrome (SARS) Coronavirus (CoV)-2 is a recently identified positive sense single-strand RNA (ssRNA) β-coronavirus. The viral spike proteins infect human hosts by binding to the cellular receptor angiotensin-converting enzyme 2 (ACE2). The infection causes a systemic illness involving cell metabolism. This widespread involvement is implicated in the pathophysiology of the illness which ranges from mild to severe, requiring multi organ support, ranging from oxygen supplementation to full cardiovascular and respiratory support. Patients with multiple co-existing comorbidities are also at a higher risk. The aim of this review is to explore the exact mechanisms by which COVID-19 affects patients systemically with a primary focus on the bleeding and thrombotic complications linked with the disease. Issues surrounding the thrombotic complications following administration of the ChAdOx1 nCoV-19 (Astra-Zeneca-Oxford) vaccine have also been illustrated. Risk stratification and treatment options in these patients should be tailored according to clinical severity with input from a multidisciplinary team.

Pulmonary Embolism Prophylaxis in Patients With COVID-19: An Emerging Issue

Severe acute respiratory syndrome (SARS)-CoV-2 virus disease (coronavirus disease 2019; COVID-19) is associated with increased coagulation activity, resulting in an excessive risk of venous thromboembolism (VTE) and poor prognosis. The most common manifestation of VTE is pulmonary embolism (PE), with approximately one in five hospitalised patients being at risk. These reports led to the empirical use of prophylactic anticoagulation, even in the absence of established or clinically suspected disease. This review summarises current aspects and recommendations regarding the use of thromboprophylaxis for PE in patients with COVID-19.

Diagnostic Value of D-Dimer in COVID-19: A Meta-Analysis and Meta-Regression

The prognostic role of hypercoagulability in COVID-19 patients is ambiguous. D-dimer, may be regarded as a global marker of hemostasis activation in COVID-19. Our study was to assess the predictive value of D-dimer for the severity, mortality and incidence of venous thromboembolism (VTE) events in COVID-19 patients. PubMed, EMBASE, Cochrane Library and Web of Science databases were searched. The pooled diagnostic value (95% confidence interval [CI]) of D-dimer was evaluated with a bivariate mixed-effects binary regression modeling framework. Sensitivity analysis and meta regression were used to determine heterogeneity and test robustness. A Spearman rank correlation tested threshold effect caused by different cut offs and units in D-dimer reports. The pooled sensitivity of the prognostic performance of D-dimer for the severity, mortality and VTE in COVID-19 were 77% (95% CI: 73%-80%), 75% (95% CI: 65%-82%) and 90% (95% CI: 90%-90%) respectively, and the specificity were 71% (95% CI: 64%-77%), 83% (95% CI: 77%-87%) and 60% (95% CI: 60%-60%). D-dimer can predict severe and fatal cases of COVID-19 with moderate accuracy. It also shows high sensitivity but relatively low specificity for detecting COVID-19-related VTE events, indicating that it can be used to screen for patients with VTE.

Therapeutic potential of mesenchymal stem cells in multiple organs affected by COVID-19

Currently, the world has been devastated by an unprecedented pandemic in this century. The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the agent of coronavirus disease 2019 (COVID-19), has been causing disorders, dysfunction and morphophysiological alterations in multiple organs as the disease evolves. There is a great scientific community effort to obtain a therapy capable of reaching the multiple affected organs in order to contribute for tissue repair and regeneration. In this regard, mesenchymal stem cells (MSCs) have emerged as potential candidates concerning the promotion of beneficial actions at different stages of COVID-19. MSCs are promising due to the observed therapeutic effects in respiratory preclinical models, as well as in cardiac, vascular, renal and nervous system models. Their immunomodulatory properties and secretion of paracrine mediators, such as cytokines, chemokines, growth factors and extracellular vesicles allow for long range tissue modulation and, particularly, blood-brain barrier crossing. This review focuses on SARS-CoV-2 impact to lungs, kidneys, heart, vasculature and central nervous system while discussing promising MSC's therapeutic mechanisms in each tissue. In addition, MSC's therapeutic effects in high-risk groups for COVID-19, such as obese, diabetic and hypertensive patients are also explored.

Late-onset of pulmonary embolism following hospitalization for COVID-19 despite thromboprophylaxis: a report of two cases

The global pandemic caused by the SARS-CoV-2 has resulted in an increased incidence of venous thromboembolism among hospitalized COVID-19-patients, especially those who required intensive care, despite thromboprophylaxis. This has resulted in the use of higher doses of thromboprophylaxis or therapeutic anticoagulation therapy even in the absence of thrombotic events. However, after their hospital discharge, authors and current guidelines are not unanimous about extended anticoagulant therapy in patients with COVID-19. Here, we report two pulmonary embolism cases following hospitalization for COVID-19, despite intermediate doses of thromboprophylaxis. These rare cases suggest that there may be a residual thrombotic risk following hospitalization for COVID-19 and highlight questions about extended prophylactic-anticoagulation therapy after hospital discharge of patients with COVID-19.

A Machine Learning Approach to Predict Deep Venous Thrombosis Among Hospitalized Patients

Deep venous thrombosis (DVT) is associated with significant morbidity, mortality, and increased healthcare costs. Standard scoring systems for DVT risk stratification often provide insufficient stratification of hospitalized patients and are unable to accurately predict which inpatients are most likely to present with DVT. There is a continued need for tools which can predict DVT in hospitalized patients. We performed a retrospective study on a database collected from a large academic hospital, comprised of 99,237 total general ward or ICU patients, 2,378 of whom experienced a DVT during their hospital stay. Gradient boosted machine learning algorithms were developed to predict a patient's risk of developing DVT at 12- and 24-hour windows prior to onset. The primary outcome of interest was diagnosis of in-hospital DVT. The machine learning predictors obtained AUROCs of 0.83 and 0.85 for DVT risk prediction on hospitalized patients at 12- and 24-hour windows, respectively. At both 12 and 24 hours before DVT onset, the most important features for prediction of DVT were cancer history, VTE history, and internal normalized ratio (INR). Improved risk stratification may prevent unnecessary invasive testing in patients for whom DVT cannot be ruled out using existing methods. Improved risk stratification may also allow for more targeted use of prophylactic anticoagulants, as well as earlier diagnosis and treatment, preventing the development of pulmonary emboli and other sequelae of DVT.

Hematological Findings in COVID-19 and Insights to Stem Cell Therapy: From Bench to Practice

Context: As the COVID-19 was spreading to all countries, its manifestations were identifying gradually, which were related to several organs. Evidence Acquisition: COVID-19 is associated with distinct hematological changes, increased serum inflammatory markers, and coagulopathy. Most of these changes are related to the patients’ prognosis and mortality, particularly in those with severe disease. Results: Firstly, we discussed the associations between COVID-19 clinical features and complications, and secondly, its hematological findings and coagulopathy are investigated. Conclusions: Such associations not only may shed light on our prognostic view of patients with COVID-19 but also will entail significant therapeutic implications. One of its key implications is to utilize the mesenchymal stem cells (MSCs) to treat patients with COVID-19. Herein, this kind of novel therapy will be discussed, as well.