Predicting Pulmonary Embolism in Total Joint Arthroplasty Patients A Pilot Study

Postoperative venous thromboembolism (VTE) is a common and costly complication following total joint arthroplasty (TJA). Development of a refined thrombophilic screening panel will better equip clinicians to identify patients at high-est risk for developing VTEs. In this pilot study, 62 high-risk TJA recipients who had developed pulmonary emboli (PE) within 90-days of surgery were eligible to participate. Of these patients, 14 were enrolled and subsequently adminis-tered a pre-determined panel of 18 hematologic tests with the aim of identifying markers that are consistently elevated or deficient in patients developing PE. A separate cohort of seven high-risk TJA recipients who did not report a symp-tomatic VTE within 90-days of surgery were then enrolled and Factor VIII and lipoprotein(a) levels were assessed. The most common aberrance was noted in 10 patients (71.4%) who had elevated levels of Factor VIII followed by five patients (35.7%) who had elevated levels of lipoprotein(a). Factor VIII was significantly prevalent (p < 0.001) while lipoprotein(a) failed to achieve statistical significance (p = 0.0708). Of the patients who were within normal limits of Factor VIII, three-fourths were "high-normal" with Fac-tor VIII levels within 5% of the upper limit of normal. This study demonstrates the potential utility of this hematologic panel as part of a perioperative screening protocol aimed at identifying patients at risk for developing VTEs. However, future larger scale studies assessing the capabilities and limitations of our findings are warranted.

Circulating Cytokines and Venous Thromboembolism: A Bidirectional Two-Sample Mendelian Randomization Study

BACKGROUND

 Epidemiological evidence has linked circulating cytokines to venous thromboembolism (VTE). However, it remains uncertain whether these associations are causal due to confounding factors or reverse causality. We aim to explore the causality between circulating cytokines and VTE, encompassing deep vein thrombosis (DVT) and pulmonary embolism (PE).

METHODS

 In the current bidirectional Mendelian randomization (MR) study, instrumental variables of 41 circulating cytokines were obtained from the genome-wide association study meta-analyses (8,293 individuals). Summary statistics for the association of VTE (17,048 cases and 325,451 controls), DVT (8,077 cases and 295,014 controls), and PE (8,170 cases and 333,487 controls) were extracted from the FinnGen Study. A multivariable MR study was conducted to adjust for potential confounders. The inverse-variance weighted method was employed as the main analysis, and comprehensive sensitivity analyses were conducted in the supplementary analyses.

RESULTS

 The MR analysis indicated stromal cell-derived factor-1α was suggestively associated with a reduced risk of VTE (odds ratio [OR]: 0.90; 95% confidence interval [CI]: 0.81-0.99; p = 0.033) and DVT (OR: 0.85; 95% CI: 0.75-0.97; p = 0.015). In addition, suggestive association of granulocyte colony-stimulating factor with PE (OR: 1.20; 95% CI: 1.06-1.37; p = 0.005) was observed. Multivariable MR analysis showed that the effect of cytokines on VTE was partly mediated through hemoglobin A1c and systolic blood pressure. Reverse MR analysis revealed that VTE was linked to decreased levels of several cytokines.

CONCLUSION

 We provide suggestive genetic evidence supporting the bidirectional causal effect between circulating cytokines and VTE, highlighting the importance of targeting circulating cytokines to reduce the incidence of VTE.

Changes and significance of the fibrinolytic system following two pulmonary thromboembolisms in a rabbit model

In this study, we examined the changes in the fibrinolytic system in a rabbit model of two acute pulmonary thromboembolisms (PTE). Fourteen healthy adult New Zealand white rabbits were divided into three groups: the single PTE group (five rabbits), the double PTE group (five rabbits), and the control group (four rabbits). A rabbit model of acute pulmonary embolism was established, and immunohistochemistry and polymerase chain reaction (PCR) were performed on tissue plasminogen activator (t-PA), plasminogen activator inhibitor-1 (PAI-1) in plasma, and pulmonary embolism tissue. Plasma results: 1) t-PA levels: one hour following the initial modeling, the levels of t-PA in the modeling groups were significantly lower than those in the control group (P<0.05). In addition, the t-PA levels in the double PTE group were found to be lower after the modeling, as compared to the pre-modeling period (P<0.05). One hour after the second modeling, the double PTE group had lower t-PA levels compared to the control group (P<0.05). However, t-PA rebounded two hours after modeling in the double PTE group. One week after the second modeling, the double PTE group had higher t-PA levels compared to the other two groups (P<0.05). 2) PAI-1 results: one hour after the initial modeling, PAI-1 levels in the two modeling groups were lower compared to the pre-modeling period and control groups (P<0.05). Two hours following modeling, PAI-1 levels in both modeling groups were lower compared to the control group (P<0.05). PAI-1 levels were lower in the double PTE group one and two hours after the second modeling compared to the other two groups and pre-modeling period (P<0.05). 3) The immunohistochemistry results: the expression of PAI-1 decreased in the two modeling groups, while t-PA expression increased compared to the control group. 4) PCR results: t-PA mRNA expression did not differ among the three groups. The PAI-1 mRNA expression was lower in the two PTE groups compared to the control group. We conclude that in the early stages of PTE, the local fibrinolytic activity of the thrombus is increased, which is favorable for thrombolysis. However, as the thrombus persists, the activity of the fibrinolytic system is inhibited, contributing to the development of chronic thromboembolic pulmonary hypertension.

Acute Pulmonary Embolism: A Review

IMPORTANCE

Pulmonary embolism (PE) is characterized by occlusion of blood flow in a pulmonary artery, typically due to a thrombus that travels from a vein in a lower limb. The incidence of PE is approximately 60 to 120 per 100 000 people per year. Approximately 60 000 to 100 000 patients die from PE each year in the US.

OBSERVATIONS

PE should be considered in patients presenting with acute chest pain, shortness of breath, or syncope. The diagnosis is determined by chest imaging. In patients with a systolic blood pressure of at least 90 mm Hg, the following 3 steps can be used to evaluate a patient with possible PE: assessment of the clinical probability of PE, D-dimer testing if indicated, and chest imaging if indicated. The clinical probability of PE can be assessed using a structured score or using clinical gestalt. In patients with a probability of PE that is less than 15%, the presence of 8 clinical characteristics (age <50 years, heart rate <100/min, an oxygen saturation level of > 94%, no recent surgery or trauma, no prior venous thromboembolism event, no hemoptysis, no unilateral leg swelling, and no estrogen use) identifies patients at very low risk of PE in whom no further testing is needed. In patients with low or intermediate clinical probability, a D-dimer level of less than 500 ng/mL is associated with a posttest probability of PE less than 1.85%. In these patients, PE can be excluded without chest imaging. A further refinement of D-dimer threshold is possible in patients aged 50 years and older, and in patients with a low likelihood of PE. Patients with a high probability of PE (ie, >40% probability) should undergo chest imaging, and D-dimer testing is not necessary. In patients with PE and a systolic blood pressure of 90 mm Hg or higher, compared with heparin combined with a vitamin K antagonist such as warfarin followed by warfarin alone, direct oral anticoagulants such as apixaban, edoxaban, rivaroxaban, or dabigatran, are noninferior for treating PE and have a 0.6% lower rate of bleeding. In patients with PE and systolic blood pressure lower than 90 mm Hg, systemic thrombolysis is recommended and is associated with an 1.6% absolute reduction of mortality (from 3.9% to 2.3%).

CONCLUSIONS AND RELEVANCE

In the US, PE affects approximately 370 000 patients per year and may cause approximately 60 000 to 100 000 deaths per year. First-line therapy consists of direct oral anticoagulants such as apixaban, edoxaban, rivaroxaban, or dabigatran, with thrombolysis reserved for patients with systolic blood pressure lower than 90 mm Hg.

Predictors of Prolonged Hospital Stay in Patients with Acute Pulmonary Thromboembolism- A Hospital Based Cohort Study

AIMS AND OBJECTIVES

Patients with pulmonary thromboembolism (PTE) are commonly admitted to hospital and generally have a prolonged hospital stay in this part of the world. We aimed to determine different clinical and laboratory parameters that are associated with prolonged hospital stay in our set-up and to analyse effectiveness of Pulmonary Embolism Severity Index (PESI) score as a predictor of prolonged hospital stay in patients with PTE.

MATERIALS AND METHODS

It was a hospital based observational prospective study. Confirmed cases of PTE defined as patients with evidence of thrombus on CT pulmonary angiogram (CTPA) were included in this study. Depending on the length of hospital stay, patients were divided into two cohorts: Shorter Hospital stay (less than mean i.e., &lt; 10 Days) and Prolonged Hospital stay (longer than mean i.e., ≥ 10 Days). Logistic regression analysis was done to identify predictors of prolonged hospital stay.

RESULTS

150 patients were included in the study with 67 patients (44.67%) having shorter hospital stay (&lt;10 days) and 83 patients (55.33%) having prolonged hospital stay (≥10 days). On multivariate regression analysis, parameters that were found to be statistically significant were hypotension at presentation, decreased level of consciousness, pco2 &lt; 30 mmHg, presence of S1Q3T3 pattern on electrocardiogram (ECG) and high risk PESI (class III-V).

CONCLUSION

PESI class can be effectively used to predict prolonged hospital stay in patients with pulmonary embolism. Patients with hypotension at presentation, decreased level of consciousness, pco2 less than 30 mmHg, and S1Q3T3 on ECG are more likely to have prolonged hospital stay in our healthcare setup.

Development and Validation of a Nomogram for Predicting the Long-Term Survival in Patients With Chronic Thromboembolic Pulmonary Hypertension

There remains a lack of prognosis models for patients with chronic thromboembolic pulmonary hypertension (CTEPH). This study aims to develop a nomogram predicting 3-, 5-, and 7-year survival in patients with CTEPH and verify the prognostic model. Patients with CTEPH diagnosed in Fuwai Hospital were enrolled consecutively between May 2013 and May 2019. Among them, 70% were randomly split into a training set and the other 30% as a validation set for external validation. Cox proportional hazards model was used to identify the potential survival-related factors which were candidate variables for the establishment of nomogram and the final model was internally validated by the bootstrap method. A total of 350 patients were included in the final analysis and the median follow-up period of the whole cohort was 51.2 months. Multivariate analysis of Cox proportional hazards regression showed body mass index, mean right atrial pressure, N-terminal pro-brain natriuretic peptide (per 500 ng/ml increase in concentration), presence of anemia, and main treatment choice were the independent risk factors of mortality. The nomogram demonstrated good discrimination with the corrected C-index of 0.82 in the training set, and the C-index of 0.80 (95% CI: 0.70 to 0.91) in the external validation set. The calibration plots also showed a good agreement between predicted and actual survival in both training and validation sets. In conclusion, we developed an easy-to-use nomogram with good apparent performance using 5 readily available variables, which may help physicians to identify CTEPH patients at high risk for poor prognosis and implement medical interventions.

A Feasibility Study on the Identification of Potential Biomarkers in Pulmonary Embolism Using Proteomic Analysis

Acute pulmonary embolism (PE) is a common emergency with a high morbidity and mortality. Most clinical presentations are non-specific and there is a lack of suitable biomarkers for PE. For example, the traditional D-dimer tests shows a rather high sensitivity for PE, but yet a rather low positive predictive value due to its lack of specificity. Research on novel biomarkers for PE is thus of interest to improve early diagnostics and reduce the number of unnecessary computed tomography pulmonary angiogram (CTPA) scans performed. In this study we evaluate the feasibility to use label-free quantitative proteomics to discover potential biomarkers for acute PE and to monitor changes in proteins levels in PE patients over time. Blood was collected from 8 patients with CTPA verified PE and from 8 patients presenting with same symptoms but with a negative CTPA. The samples were analyzed by liquid chromatography-mass spectrometry and thirteen protein concentrations were found to be significantly changed in PE patients compared to the CTPA negative controls. This exploratory study shows that proteomic analysis can be used to identify potential biomarkers for PE as well as to monitor changes of protein levels over time.The complement proteins play a part in PE but further studies are needed to clarify their specific role in the pathophysiological process and to look for more specific proteins.

Enoxaparin titrated by anti-Xa levels reduces venous thromboembolism in trauma patients

BACKGROUND

Trauma is a major risk factor for the development of a venous thromboembolism (VTE). After observing higher than expected VTE rates within our center's Trauma Quality Improvement Program data, we instituted a change in our VTE prophylaxis protocol, moving to enoxaparin dosing titrated by anti-Xa levels. We hypothesized that this intervention would lower our symptomatic VTE rates.

METHODS

Adult trauma patients at a single institution meeting National Trauma Data Standard criteria from April 2015 to September 2019 were examined with regards to VTE chemoprophylaxis regimen and VTE incidence. Two groups of patients were identified based on VTE protocol-those who received enoxaparin 30 mg twice daily without routine anti-Xa levels ("pre") versus those who received enoxaparin 40 mg twice daily with dose titrated by serial anti-Xa levels ("post"). Univariate and multivariate analyses were performed to define statistically significant differences in VTE incidence between the two cohorts.

RESULTS

There were 1698 patients within the "pre" group and 1406 patients within the "post" group. The two groups were essentially the same in terms of demographics and risk factors for bleeding or thrombosis. There was a statistically significant reduction in VTE rate (p = 0.01) and deep vein thrombosis rate (p = 0.01) but no significant reduction in pulmonary embolism rate (p = 0.21) after implementation of the anti-Xa titration protocol. Risk-adjusted Trauma Quality Improvement Program data showed an improvement in rate of symptomatic pulmonary embolism from fifth decile to first decile.

CONCLUSION

A protocol titrating prophylactic enoxaparin dose based on anti-Xa levels reduced VTE rates. Implementation of this type of protocol requires diligence from the physician and pharmacist team. Further research will investigate the impact of protocol compliance and time to appropriate anti-Xa level on incidence of VTE.

LEVEL OF EVIDENCE

Therapeutic/care management, Level IV.

Effect of a Diagnostic Strategy Using an Elevated and Age-Adjusted D-Dimer Threshold on Thromboembolic Events in Emergency Department Patients With Suspected Pulmonary Embolism: A Randomized Clinical Trial

IMPORTANCE

Uncontrolled studies suggest that pulmonary embolism (PE) can be safely ruled out using the YEARS rule, a diagnostic strategy that uses varying D-dimer thresholds.

OBJECTIVE

To prospectively validate the safety of a strategy that combines the YEARS rule with the pulmonary embolism rule-out criteria (PERC) rule and an age-adjusted D-dimer threshold.

DESIGN, SETTINGS, AND PARTICIPANTS

A cluster-randomized, crossover, noninferiority trial in 18 emergency departments (EDs) in France and Spain. Patients (N = 1414) who had a low clinical risk of PE not excluded by the PERC rule or a subjective clinical intermediate risk of PE were included from October 2019 to June 2020, and followed up until October 2020.

INTERVENTIONS

Each center was randomized for the sequence of intervention periods. In the intervention period (726 patients), PE was excluded without chest imaging in patients with no YEARS criteria and a D-dimer level less than 1000 ng/mL and in patients with 1 or more YEARS criteria and a D-dimer level less than the age-adjusted threshold (500 ng/mL if age <50 years or age in years × 10 in patients ≥50 years). In the control period (688 patients), PE was excluded without chest imaging if the D-dimer level was less than the age-adjusted threshold.

MAIN OUTCOMES AND MEASURES

The primary end point was venous thromboembolism (VTE) at 3 months. The noninferiority margin was set at 1.35%. There were 8 secondary end points, including chest imaging, ED length of stay, hospital admission, nonindicated anticoagulation treatment, all-cause death, and all-cause readmission at 3 months.

RESULTS

Of the 1414 included patients (mean age, 55 years; 58% female), 1217 (86%) were analyzed in the per-protocol analysis. PE was diagnosed in the ED in 100 patients (7.1%). At 3 months, VTE was diagnosed in 1 patient in the intervention group (0.15% [95% CI, 0.0% to 0.86%]) vs 5 patients in the control group (0.80% [95% CI, 0.26% to 1.86%]) (adjusted difference, -0.64% [1-sided 97.5% CI, -∞ to 0.21%], within the noninferiority margin). Of the 6 analyzed secondary end points, only 2 showed a statistically significant difference in the intervention group compared with the control group: chest imaging (30.4% vs 40.0%; adjusted difference, -8.7% [95% CI, -13.8% to -3.5%]) and ED median length of stay (6 hours [IQR, 4 to 8 hours] vs 6 hours [IQR, 5 to 9 hours]; adjusted difference, -1.6 hours [95% CI, -2.3 to -0.9]).

CONCLUSIONS AND RELEVANCE

Among ED patients with suspected PE, the use of the YEARS rule combined with the age-adjusted D-dimer threshold in PERC-positive patients, compared with a conventional diagnostic strategy, did not result in an inferior rate of thromboembolic events.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04032769.

COVID-19 associated pulmonary embolism with D-dimer values within the referent range: a case report and review of the literature

OBJECTIVE

COVID-19 is associated with an increased incidence of pulmonary embolism (PE). Elevated D-dimer levels are linked to an increased risk of PE and poor clinical outcome. We reported a case of PE in a COVID-19 patient with normal D-dimer levels and conducted a review of the literature on the subject.

CASE REPORT

A 38-year-old man with no prior comorbidities returned to the COVID-19 outpatient clinic 36 hours after being discharged from the hospital, where he had been treated for COVID-19 pneumonia. He reported a sudden feeling of dyspnea and chest pain. The physical examination was unremarkable. No new changes were detected on the chest X-ray. D-dimer and cardiac-specific markers values were within the referent range. The patient underwent an urgent computerized tomography pulmonary angiography which revealed signs of bilateral arterial thrombosis. He was treated with a therapeutic dose of low molecular weight heparin and discharged after 15 days, with a recommendation to use a direct oral anticoagulant.

CONCLUSIONS

Healthcare professionals should be aware that PE can occur as a late complication of COVID-19. Clinical suspicion of PE should lead physicians to use additional diagnostic methods to confirm or rule out PE, even if D-dimer levels are within the referent range.

TNF-α and HMGB1: New Biomarkers of Acute Pulmonary Embolism

OBJECTIVE

Inflammatory mediators have been implicated in the pathophysiology of acute pulmonary embolism (PE). However, the role of inflammatory mediator activation in the development of pulmonary embolism remains elusive. Here, we determined the reliability of the plasma levels of inflammatory markers tumor necrosis factor-alpha (TNF-α) and high mobility histone 1 (HMGB1) as diagnostic biomarkers of PE.

METHODS

Eighty-seven patients with PE and ninety-two healthy adults were enrolled. Plasma levels of TNF-α and HMGB1 were measured before and after anticoagulation treatment using conventional commercialized ELISA.

RESULTS

The mean concentrations of plasma TNF-α and HMGB1 in patients with PE before anticoagulation treatment were 3.36- and 2.54-fold higher than those in controls (p<0.0001), respectively. Similar results were obtained in patients with PE before anticoagulation treatment, in which plasma levels of TNF-α and HMGB1 were 3.99- and 1.99-fold higher (p<0.0001), respectively, than in PE patients after anticoagulation treatment. Among the two potential markers, TNF-α performed best in distinguishing patients with PE from controls. A significant positive correlation was found between the two markers' concentrations.

CONCLUSIONS

These findings suggest that the plasma levels of TNF-α and HMGB1 may serve as potential biomarkers for PE.

Effect of a Pulmonary Embolism Diagnostic Strategy on Clinical Outcomes in Patients Hospitalized for COPD Exacerbation: A Randomized Clinical Trial

IMPORTANCE

Active search for pulmonary embolism (PE) may improve outcomes in patients hospitalized for exacerbations of chronic obstructive pulmonary disease (COPD).

OBJECTIVE

To compare usual care plus an active strategy for diagnosing PE with usual care alone in patients hospitalized for COPD exacerbation.

DESIGN, SETTING, AND PARTICIPANTS

Randomized clinical trial conducted across 18 hospitals in Spain. A total of 746 patients were randomized from September 2014 to July 2020 (final follow-up was November 2020).

INTERVENTIONS

Usual care plus an active strategy for diagnosing PE (D-dimer testing and, if positive, computed tomography pulmonary angiogram) (n = 370) vs usual care (n = 367).

MAIN OUTCOMES AND MEASURES

The primary outcome was a composite of nonfatal symptomatic venous thromboembolism (VTE), readmission for COPD, or death within 90 days after randomization. There were 4 secondary outcomes, including nonfatal new or recurrent VTE, readmission for COPD, and death from any cause within 90 days. Adverse events were also collected.

RESULTS

Among the 746 patients who were randomized, 737 (98.8%) completed the trial (mean age, 70 years; 195 [26%] women). The primary outcome occurred in 110 patients (29.7%) in the intervention group and 107 patients (29.2%) in the control group (absolute risk difference, 0.5% [95% CI, -6.2% to 7.3%]; relative risk, 1.02 [95% CI, 0.82-1.28]; P = .86). Nonfatal new or recurrent VTE was not significantly different in the 2 groups (0.5% vs 2.5%; risk difference, -2.0% [95% CI, -4.3% to 0.1%]). By day 90, a total of 94 patients (25.4%) in the intervention group and 84 (22.9%) in the control group had been readmitted for exacerbation of COPD (risk difference, 2.5% [95% CI, -3.9% to 8.9%]). Death from any cause occurred in 23 patients (6.2%) in the intervention group and 29 (7.9%) in the control group (risk difference, -1.7% [95% CI, -5.7% to 2.3%]). Major bleeding occurred in 3 patients (0.8%) in the intervention group and 3 patients (0.8%) in the control group (risk difference, 0% [95% CI, -1.9% to 1.8%]; P = .99).

CONCLUSIONS AND RELEVANCE

Among patients hospitalized for an exacerbation of COPD, the addition of an active strategy for the diagnosis of PE to usual care, compared with usual care alone, did not significantly improve a composite health outcome. The study may not have had adequate power to assess individual components of the composite outcome.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02238639.

D-Dimer Testing for the Exclusion of Pulmonary Embolism Among Hospitalized Patients With COVID-19

This prognostic study evaluates the use of plasma D-dimer concentrations to rule out pulmonary embolism among patients hospitalized with COVID-19.

Thromboprophylaxis strategies to improve the prognosis of COVID-19

The outbreak of 2019 novel coronavirus disease (Covid-19) has deeply challenged the world population, but also our medical knowledge. Special attention has been paid early to an activation of coagulation, then to an elevated rate of venous thromboembolism (VTE) in patients hospitalized with severe COVID-19. These data suggested that anticoagulant drugs should be evaluated in the treatment of patients with COVID-19. The publication of unexpected high rates of VTE in patients hospitalized with COVID-19, despite receiving thromboprophylaxis, open the way to dedicated trials, evaluating modified regimens of thromboprophylaxis. Moreover, the further improvement in our comprehension of the disease, particularly the pulmonary endothelial dysfunction increased the hope that anticoagulant drugs may also protect patients from pulmonary thrombosis. In this comprehensive review, we cover the different situations where thromboprophylaxis standard may be modified (medically-ill inpatients, ICU inpatients, outpatients), and describe some of the current randomized controls trials evaluating new regimens of thromboprophylaxis in patients with COVID-19, including the preliminary available results. We also discuss the potential of anticoagulant drugs to target the thromboinflammation described in patients with severe COVID-19.

Pathophysiology of SARS-CoV-2: the Mount Sinai COVID-19 autopsy experience

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its associated clinical syndrome COVID-19 are causing overwhelming morbidity and mortality around the globe and disproportionately affected New York City between March and May 2020. Here, we report on the first 100 COVID-19-positive autopsies performed at the Mount Sinai Hospital in New York City. Autopsies revealed large pulmonary emboli in six cases. Diffuse alveolar damage was present in over 90% of cases. We also report microthrombi in multiple organ systems including the brain, as well as hemophagocytosis. We additionally provide electron microscopic evidence of the presence of the virus in our samples. Laboratory results of our COVID-19 cohort disclose elevated inflammatory markers, abnormal coagulation values, and elevated cytokines IL-6, IL-8, and TNFα. Our autopsy series of COVID-19-positive patients reveals that this disease, often conceptualized as a primarily respiratory viral illness, has widespread effects in the body including hypercoagulability, a hyperinflammatory state, and endothelial dysfunction. Targeting of these multisystemic pathways could lead to new treatment avenues as well as combination therapies against SARS-CoV-2 infection.

Increased activity of procoagulant factors in patients with small cell lung cancer

Small cell lung cancer (SCLC) patients have augmented risk of developing venous thromboembolism, but the mechanisms triggering this burden on the coagulation system remain to be understood. Recently, cell-derived microparticles carrying procoagulant phospholipids (PPL) and tissue factor (TF) in their membrane have attracted attention as possible contributors to the thrombogenic processes in cancers. The aims of this study were to assess the coagulation activity of platelet-poor plasma from 38 SCLC patients and to provide a detailed procoagulant profiling of small and large extracellular vesicles (EVs) isolated from these patients at the time of diagnosis, during and after treatment compared to 20 healthy controls. Hypercoagulability testing was performed by thrombin generation (TG), procoagulant phospholipid (PPL), TF activity, Protein C, FVIII activity and cell-free deoxyribonucleic acid (cfDNA), a surrogate measure for neutrophil extracellular traps (NETs). Our results revealed a coagulation activity that is significantly increased in the plasma of SCLC patients when compared to age-related healthy controls, but no substantial changes in coagulation activity during treatment and at follow-up. Although EVs in the patients revealed an increased PPL and TF activity compared with the controls, the TG profiles of EVs added to a standard plasma were similar for patients and controls. Finally, we found no differences in the coagulation profile of patients who developed VTE to those who did not, i.e. the tests could not predict VTE. In conclusion, we found that SCLC patients display an overall increased coagulation activity at time of diagnosis and during the disease, which may contribute to their higher risk of VTE.

Elimination of fibrin γ-chain cross-linking by FXIIIa increases pulmonary embolism arising from murine inferior vena cava thrombi

The onset of venous thromboembolism, including pulmonary embolism, represents a significant health burden affecting more than 1 million people annually worldwide. Current treatment options are based on anticoagulation, which is suboptimal for preventing further embolic events. In order to develop better treatments for thromboembolism, we sought to understand the structural and mechanical properties of blood clots and how this influences embolism in vivo. We developed a murine model in which fibrin γ-chain cross-linking by activated Factor XIII is eliminated (FGG3X) and applied methods to study thromboembolism at whole-body and organ levels. We show that FGG3X mice have a normal phenotype, with overall coagulation parameters and platelet aggregation and function largely unaffected, except for total inhibition of fibrin γ-chain cross-linking. Elimination of fibrin γ-chain cross-linking resulted in thrombi with reduced strength that were prone to fragmentation. Analysis of embolism in vivo using Xtreme optical imaging and light sheet microscopy demonstrated that the elimination of fibrin γ-chain cross-linking resulted in increased embolization without affecting clot size or lysis. Our findings point to a central previously unrecognized role for fibrin γ-chain cross-linking in clot stability. They also indirectly indicate mechanistic targets for the prevention of thrombosis through selective modulation of fibrin α-chain but not γ-chain cross-linking by activated Factor XIII to reduce thrombus size and burden, while maintaining clot stability and preventing embolism.

Synthetic Fibrin-Derived Bβ15-42 Peptide Delays Thrombus Resolution in a Mouse Model

[Figure: see text].

P-selectin antibody treatment after blunt thoracic trauma prevents early pulmonary arterial thrombosis without changes in viscoelastic measurements of coagulation

INTRODUCTION

Previously, in a murine model of blunt thoracic trauma, we provided evidence of primary pulmonary thrombosis associated with increased expression of the cell adhesion molecule, P-selectin. In this study, mice are treated with P-selectin blocking antibody after injury to investigate the clinical viability of this antibody for the prevention of pulmonary thrombosis. In addition, viscoelastic testing is performed to investigate if P-selectin inhibition has a detrimental impact on normal hemostasis.

METHODS

A murine model of thoracic trauma was used. Mice were divided into sham control and experimental injury groups. Thirty minutes after trauma, mice were treated with the following: P-selectin blocking antibody, isotype control antibody, low-dose heparin, high-dose heparin, or normal saline. At 90 minutes, whole blood was collected for characterization of coagulation by viscoelastic coagulation monitor (VCM Vet; Entegrion, Durham, NC). Mean clotting time, clot formation time, clot kinetics (α angle), and maximum clot firmness were compared between each treatment group.

RESULTS

Mice that received P-selectin antibody 30 minutes after blunt thoracic trauma had four- to fivefold less (p < 0.001) arterial fibrin accumulation than those that received the isotype control. In both sham and trauma groups, compared with vehicle (normal saline) alone, no statistical difference was noted in any coagulation parameters after injection with P-selectin antibody, isotype control, or low-dose heparin. In addition, blinded histopathological evaluation yielded no difference in hemorrhage scores between injured mice treated with P-selectin blocking antibody and those treated with isotype antibody control.

CONCLUSION

This study supports the clinical use of P-selectin blocking antibody for the prevention of pulmonary thrombosis by confirming its efficacy when given after a blunt thoracic trauma. In addition, we demonstrated that the administration of P-selectin antibody does not adversely affect systemic coagulation as measured by viscoelastic testing, suggesting that P-selectin antibody can be safely given during the acute posttraumatic period.

Prognostic value of red blood cell distribution width in patients with acute pulmonary embolism: A protocol for systematic review and meta-analysis

BACKGROUND

Prior reports have suggested that the red blood cell distribution width (RDW) parameter could be measured as a prognostic indicator in pulmonary embolism (PE) patients, thereby helping to guide their care. However, no systematic analyses on this topic have been completed to date, and the exact relationship between RDW and PE remains to be fully clarified. We will therefore conduct a systematic literature review with the goal of defining the correlation between RDW and mortality in acute PE cases.

METHODS

The EMBASE, Web of Knowledge, PubMed, ClinicalTrials.gov, and Cochrane Library databases will be searched for all relevant studies published from inception through March 2021 using the following search strategy: ("red blood cell distribution width") AND ("pulmonary embolism"). Two authors will independently identify eligible studies and extract data. The Q and I2 statistics will be used to judge heterogeneity among studies.

RESULTS

This study will establish the relative efficacy of RDW as a metric for predicting PE patient mortality.

CONCLUSIONS

This study will offer a reliable, evidence-based foundation for the clinical utilization of RDW as a tool for gauging mortality risk in acute PE patients.

ETHICS AND DISSEMINATION

As this is a protocol for a systematic review of previously published data, no ethical approval is required. Electronic dissemination of study results will be done through a peer-review publication or represented at a related conference.

D-Dimer Level and Neutrophils Count as Predictive and Prognostic Factors of Pulmonary Embolism in Severe Non-ICU COVID-19 Patients

The incidence of pulmonary embolism (PE) is high during severe Coronavirus Disease 2019 (COVID-19). We aimed to identify predictive and prognostic factors of PE in non-ICU hospitalized COVID-19 patients. In the retrospective multicenter observational CLOTVID cohort, we enrolled patients with confirmed RT-PCR COVID-19 who were hospitalized in a medicine ward and also underwent a CT pulmonary angiography for a PE suspicion. Baseline data, laboratory biomarkers, treatments, and outcomes were collected. Predictive and prognostics factors of PE were identified by using logistic multivariate and by Cox regression models, respectively. A total of 174 patients were enrolled, among whom 86 (median [IQR] age of 66 years [55–77]) had post-admission PE suspicion, with 30/86 (34.9%) PE being confirmed. PE occurrence was independently associated with the lack of long-term anticoagulation or thromboprophylaxis (OR [95%CI], 72.3 [3.6–4384.8]) D-dimers ≥ 2000 ng/mL (26.3 [4.1–537.8]) and neutrophils ≥ 7.0 G/L (5.8 [1.4–29.5]). The presence of these two biomarkers was associated with a higher risk of PE (p = 0.0002) and death or ICU transfer (HR [95%CI], 12.9 [2.5–67.8], p < 0.01). In hospitalized non-ICU severe COVID-19 patients with clinical PE suspicion, the lack of anticoagulation, D-dimers ≥ 2000 ng/mL, neutrophils ≥ 7.0 G/L, and these two biomarkers combined might be useful predictive markers of PE and prognosis, respectively.

Inflammatory Biomarkers in the Short-Term Prognosis of Venous Thromboembolism: A Narrative Review

The relationship between inflammation and venous thrombosis is not well understood. An inflammatory response may be both the cause and consequence of venous thromboembolism (VTE). In fact, several risk factors of VTE modulate thrombosis through inflammatory markers. Acute pulmonary embolism (PE) is burdened by a remarkable mortality rate, up to 34% in severely ill patients presenting with hemodynamic instability. Initial mortality risk stratification is based on hemodynamic instability. Patients with a situation of hemodynamic stability require immediate further risk assessment based on clinical, imaging, and circulating biomarkers, as well as the presence of comorbidities. Some inflammatory biomarkers have shown potential usefulness in the risk stratification of patients with VTE, especially acute PE. C-reactive protein on admission is associated with 30-day mortality and bleeding in VTE patients. P-selectin is associated with right ventricle dysfunction in PE patients and might be associated with VTE recurrences and the extension of thrombosis. Tissue factor microparticles are associated with VTE recurrence in cancer-associated thrombosis. Other inflammatory biomarkers present scarce evidence (inflammatory cytokines, erythrocyte sedimentation rate, fibrinogen, leukocyte count). In this manuscript, we will review the prognostic role of different inflammatory biomarkers available both for clinical practice and research in VTE patients.

Pulmonary Embolism Response Team activation during the COVID-19 pandemic in a New York City Academic Hospital: a retrospective cohort analysis

Coronavirus disease 2019 (COVID-19) is associated with increased rates of deep vein thrombosis (DVT) and pulmonary embolism (PE). Pulmonary Embolism Response Teams (PERT) have previously been associated with improved outcomes. We aimed to investigate whether PERT utilization, recommendations, and outcomes for patients diagnosed with acute PE changed during the COVID-19 pandemic. This is a retrospective cohort study of all adult patients with acute PE who received care at an academic hospital system in New York City between March 1st and April 30th, 2020. These patients were compared against historic controls between March 1st and April 30th, 2019. PE severity, PERT utilization, initial management, PERT recommendations, and outcomes were compared. There were more cases of PE during the pandemic (82 vs. 59), but less PERT activations (26.8% vs. 64.4%, p < 0.001) despite similar markers of PE severity. PERT recommendations were similar before and during the pandemic; anticoagulation was most recommended (89.5% vs. 86.4%, p = 0.70). During the pandemic, those with PERT activations were more likely to be female (63.6% vs. 31.7%, p = 0.01), have a history of DVT/PE (22.7% vs. 1.7%, p = 0.01), and to be SARS-CoV-2 PCR negative (68.2% vs. 38.3% p = 0.02). PERT activation during the pandemic is associated with decreased length of stay (7.7 ± 7.7 vs. 13.2 ± 12.7 days, p = 0.02). PERT utilization decreased during the COVID-19 pandemic and its activation was associated with different biases. PERT recommendations and outcomes were similar before and during the pandemic, and led to decreased length of stay during the pandemic.

NADPH Oxidases Are Required for Full Platelet Activation In Vitro and Thrombosis In Vivo but Dispensable for Plasma Coagulation and Hemostasis

OBJECTIVE

Using 3KO (triple NOX [NADPH oxidase] knockout) mice (ie, NOX1-/-/NOX2-/-/NOX4-/-), we aimed to clarify the role of this family of enzymes in the regulation of platelets in vitro and hemostasis in vivo. Approach and Results: 3KO mice displayed significantly reduced platelet superoxide radical generation, which was associated with impaired platelet aggregation, adhesion, and thrombus formation in response to the key agonists collagen and thrombin. A comparison with single-gene knockouts suggested that the phenotype of 3KO platelets is the combination of the effects of the genetic deletion of NOX1 and NOX2, while NOX4 does not show any significant function in platelet regulation. 3KO platelets displayed significantly higher levels of cGMP-a negative platelet regulator that activates PKG (protein kinase G). The inhibition of PKG substantially but only partially rescued the defective phenotype of 3KO platelets, which are responsive to both collagen and thrombin in the presence of the PKG inhibitors KT5823 or Rp-8-pCPT-cGMPs, but not in the presence of the NOS (NO synthase) inhibitor L-NG-monomethyl arginine. In vivo, triple NOX deficiency protected against ferric chloride-driven carotid artery thrombosis and experimental pulmonary embolism, while hemostasis tested in a tail-tip transection assay was not affected. Procoagulatory activity of platelets (ie, phosphatidylserine surface exposure) and the coagulation cascade in platelet-free plasma were normal.

CONCLUSIONS

This study indicates that inhibiting NOXs has strong antithrombotic effects partially caused by increased intracellular cGMP but spares hemostasis. NOXs are, therefore, pharmacotherapeutic targets to develop new antithrombotic drugs without bleeding side effects.

Pulmonary Embolism and Deep Vein Thrombosis in COVID-19: A Systematic Review and Meta-Analysis

Background The association of pulmonary embolism (PE) with deep vein thrombosis (DVT) in patients with coronavirus disease 2019 (COVID-19) remains unclear, and the diagnostic accuracy of D-dimer tests for PE is unknown. Purpose To conduct meta-analysis of the study-level incidence of PE and DVT and to evaluate the diagnostic accuracy of D-dimer tests for PE from multicenter individual patient data. Materials and Methods A systematic literature search identified studies evaluating the incidence of PE or DVT in patients with COVID-19 from January 1, 2020, to June 15, 2020. These outcomes were pooled using a random-effects model and were further evaluated using metaregression analysis. The diagnostic accuracy of D-dimer tests for PE was estimated on the basis of individual patient data using the summary receiver operating characteristic curve. Results Twenty-seven studies with 3342 patients with COVID-19 were included in the analysis. The pooled incidence rates of PE and DVT were 16.5% (95% CI: 11.6, 22.9; I2 = 0.93) and 14.8% (95% CI: 8.5, 24.5; I2 = 0.94), respectively. PE was more frequently found in patients who were admitted to the intensive care unit (ICU) (24.7% [95% CI: 18.6, 32.1] vs 10.5% [95% CI: 5.1, 20.2] in those not admitted to the ICU) and in studies with universal screening using CT pulmonary angiography. DVT was present in 42.4% of patients with PE. D-dimer tests had an area under the receiver operating characteristic curve of 0.737 for PE, and D-dimer levels of 500 and 1000 μg/L showed high sensitivity (96% and 91%, respectively) but low specificity (10% and 24%, respectively). Conclusion Pulmonary embolism (PE) and deep vein thrombosis (DVT) occurred in 16.5% and 14.8% of patients with coronavirus disease 2019 (COVID-19), respectively, and more than half of patients with PE lacked DVT. The cutoffs of D-dimer levels used to exclude PE in preexisting guidelines seem applicable to patients with COVID-19. © RSNA, 2020 Supplemental material is available for this article. See also the editorial by Woodard in this issue.

Incidence and characterization of acute pulmonary embolism in patients with SARS-CoV-2 pneumonia: A multicenter Italian experience

BACKGROUND AND AIMS

Several studies reported a high incidence of pulmonary embolism (PE) among patients with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection, but detailed data about clinical characteristics, risk factors of these patients and prognostic role of PE are still lacking. We aim to evaluate the occurrence of pulmonary embolism among patients with SARS-CoV-2 infection, and to describe their risk factors, clinical characteristics, and in-hospital clinical outcomes.

METHODS

This is a multicenter Italian study including 333 consecutive SARS-CoV-2 patients admitted to seven hospitals from February 22 to May 15, 2020. All the patients underwent computed tomography pulmonary angiography (CTPA) for PE detection. In particular, CTPA was performed in case of inadequate response to high-flow oxygen therapy (Fi02≥0.4 to maintain Sp02≥92%), elevated D-dimer (>0.5μg/mL), or echocardiographic signs of right ventricular dysfunction. Clinical, laboratory and radiological data were also analyzed.

RESULTS

Among 333 patients with laboratory confirmed SARS-CoV-2 pneumonia and undergoing CTPA, PE was detected in 109 (33%) cases. At CTPA, subsegmental, segmental, lobar and central thrombi were detected in 31 (29%), 50 (46%), 20 (18%) and 8 (7%) cases, respectively. In-hospital death occurred in 29 (27%) patients in the PE-group and in 47 (21%) patients in the non-PE group (p = 0.25). Patients in PE-group had a low rate of traditional risk factors and deep vein thrombosis was detected in 29% of patients undergoing compression ultrasonography. In 71% of cases with documented PE, the thrombotic lesions were located in the correspondence of parenchymal consolidation areas.

CONCLUSIONS

Despite a low rate of risk factors for venous thromboembolism, PE is present in about 1 out 3 patients with SARS-CoV-2 pneumonia undergoing CTPA for inadequate response to oxygen therapy, elevated D-dimer level, or echocardiographic signs of right ventricular dysfunction. In most of the cases, the thromboses were located distally in the pulmonary tree and were mainly confined within pneumonia areas.

Prevalence and characteristics of pulmonary embolism in 1042 COVID-19 patients with respiratory symptoms: A nested case-control study

INTRODUCTION

Coronavirus disease 2019 (COVID-19) has been associated with cardiovascular complications and coagulation disorders. Previous studies reported pulmonary embolism (PE) in severe COVID-19 patients. Aim of the study was to estimate the prevalence of symptomatic PE in COVID-19 patients and to identify the clinical, radiological or biological characteristics associated with PE.

PATIENTS/METHODS

We conducted a retrospective nested case-control study in 2 French hospitals. Controls were matched in a 1:2 ratio on the basis of age, sex and center. PE patients with COVID-19 were compared to patients in whom PE was ruled out (CTPA controls) and in whom PE has not been investigated (CT controls).

RESULTS

PE was suspected in 269 patients among 1042 COVID-19 patients, and confirmed in 59 patients (5.6%). Half of PE was diagnosed at COVID-19 diagnosis. PE patients did not differ from CT and CTPA controls for thrombosis risk factors. PE patients more often required invasive ventilation compared to CTPA controls (odds ratio (OR) 2.79; 95% confidence interval (CI) 1.33-5.84) and to CT controls (OR 8.07; 95% CI 2.70-23.82). PE patients exhibited more extensive parenchymal lesions (>50%) than CT controls (OR 3.90; 95% CI 1.54-9.94). D-dimer levels were 5.1 (95% CI 1.90-13.76) times higher in PE patients than CTPA controls.

CONCLUSIONS

Our results suggest a PE prevalence in COVID-19 patients close to 5% in the whole population and to 20% of the clinically suspected population. PE seems to be associated with more extensive lung damage and to require more frequently invasive ventilation.

Thrombotic Complications of COVID-19 Infection: A Review

The novel coronavirus (severe acute respiratory syndrome CoV-2 [SARS-CoV-2]), also known as COVID-19, is a single-stranded enveloped RNA virus that created a Public Health Emergency of International Concern in January 2020, with a global case burden of over 15 million in just 7 months. Infected patients develop a wide range of clinical manifestations-typically presenting with fever, cough, myalgia, and fatigue. Severely ill patients may fall victim to acute respiratory distress syndrome, acute heart injuries, neurological manifestations, or complications due to secondary infections. These critically ill patients are also found to have disrupted coagulation function, predisposing them to consumptive coagulopathies, and both venous and thromboembolic complications. Common laboratory findings include thrombocytopenia, elevated D-dimer, fibrin degradation products, and fibrinogen, all of which have been associated with greater disease severity. Many cases of pulmonary embolism have been noted, along with deep vein thrombosis, ischemic stroke, myocardial infarction, and systemic arterial embolism. The pathogenesis of coronavirus has not been completely elucidated, but the virus is known to cause excessive inflammation, endothelial injury, hypoxia, and disseminated intravascular coagulation, all of which contribute to thrombosis formation. These patients are also faced with prolonged immobilization while staying in the hospital or intensive care unit. It is important to have a high degree of suspicion for thrombotic complications as patients may rapidly deteriorate in severe cases. Evidence suggests that prophylaxis with anticoagulation may lead to a lower risk of mortality, although it does not eliminate the possibility. The risks and benefits of anticoagulation treatment should be considered in each case. Patients should be regularly evaluated for bleeding risks and thrombotic complications.

Can pregnancy-adapted algorithms avoid diagnostic imaging for pulmonary embolism?

The low prevalence of pulmonary embolism (PE) among pregnant patients presenting with suspected PE implies that most of these patients will be found not have the disease. Given this low prevalence, excluding PE in this population has necessitated the use of sensitive and specific diagnostic imaging, such as computed tomography pulmonary angiography or ventilation-perfusion scanning. Recent studies suggest that a clinical prediction rule with D-dimer testing can also be used to exclude a subset of pregnant patients with suspected PE without the need for diagnostic imaging. The YEARS criteria, which consist of clinical signs and symptoms of deep venous thrombosis, hemoptysis, and PE as the most likely diagnosis (a subjective variable), combined with selective D-dimer levels, seem to safely exclude up to one-third of these patients without imaging. The revised Geneva rule using objective variables, combined with nonpregnancy cutoffs for D-dimer levels, offers some promise, although fewer patients avoided imaging (14%). These recent studies provide evidence in support of radiation avoidance for some patients; however, for most, imaging remains the only option. Future studies should focus on improving the safety and techniques of imaging modalities, in addition to improving the specificity of D-dimer testing and objective prediction rules. Studies assessing patients' and physicians' values, preferences, and risk perceptions are also required to assist clinicians in shared decision making when counseling pregnant patients with suspected PE.

Revisiting One of the Dreaded Outcomes of the Current Pandemic: Pulmonary Embolism in COVID-19

Pulmonary embolism (PE) is a commonly encountered clinical entity in patients with coronavirus disease 2019 (COVID-19). Up to 1/3 of patients have been found to have PE in the setting of COVID-19. Given the novelty of the virus causing this pandemic, it has not been easy to address diagnostic and management issues in PE. Ongoing research and publications of the scientific literature have helped in dealing with COVID-19 lately and this applies to PE as well. In this article, we attempt to succinctly yet comprehensively discuss PE in patients with COVID-19 with a review of the prevailing literature.

Assessing the severity of pulmonary embolism among patients in the emergency department: Utility of RV/LV diameter ratio

Background

Acute pulmonary embolism (APE) is a major cause of death from cardiovascular disease. Right ventricular systolic dysfunction (RVD) caused by APE is closely related to a poor outcome. Early risk stratification of APE is a vital step in prognostic assessment. The objective of this study was to investigate the usefulness of computed tomographic pulmonary angiography (CTPA) measured right ventricular (RV)/ left ventricular (LV) diameter ratio by the emergency department (ED) specialists for early risk stratification of APE patients in ED.

Methods

The retrospective data of 229 APE patients were reviewed. Two ED specialists measured both RV and LV diameters on a single transverse scan perpendicular to the long axis of the heart. The patients were divided into two groups, RV/LV diameter ratio <1 and ratio >1. CTPA measured RV/LV diameter ratio were analyzed and compared with sPESI score, cardiac biomarkers such as N-Terminal Pro-B-Type Natriuretic Peptide (NT-pro-BNP), high sensitivity cardiac troponin T (hs-cTnT), and RVD measured by echocardiography (Echo).

Results

The mean age in RV/LV > 1 group was significantly higher than that of the other group (67.81±2.7 years vs. 60.68±3.2 years). Also, there were more hypertension patients (44.4% vs. 33.3%), and mean arterial pressure (MAP) was lower. A significantly higher ICU admission rate (28.05% vs. 11.61%) was shown in RV/LV >1 group, and five patients expired only in RV/LV > 1 group. RVD by Echo demonstrated the highest sensitivity, specificity, and negative predictive value (NPV) (values of 94.3%, 81.1%, 95.5%). RV/LV >1 diameter ratio by CTPA showed usefulness equivalent to cardiac biomarkers. RV/LV >1 patients’ cardiac enzymes were higher, and there were more RVD in RV/LV >1 group.

Conclusion

Simple measurement of RV/LV diameter ratio by ED specialist would be a help to the clinicians in identifying and stratifying the risk of the APE patients presenting in the ED.

COVID-19, microthromboses, inflammation, and platelet activating factor

Recent articles report elevated markers of coagulation, endothelial injury, and microthromboses in lungs from deceased COVID-19 patients. However, there has been no discussion of what may induce intravascular coagulation. Platelets are critical in the formation of thrombi and their most potent trigger is platelet activating factor (PAF), first characterized by Demopoulos and colleagues in 1979. PAF is produced by cells involved in host defense and its biological actions bear similarities with COVID-19 disease manifestations. PAF can also stimulate perivascular mast cell activation, leading to inflammation implicated in severe acute respiratory syndrome (SARS). Mast cells are plentiful in the lungs and are a rich source of PAF and of inflammatory cytokines, such as IL-1β and IL-6, which may contribute to COVID-19 and especially SARS. The histamine-1 receptor antagonist rupatadine was developed to have anti-PAF activity, and also inhibits activation of human mast cells in response to PAF. Rupatadine could be repurposed for COVID-19 prophylaxis alone or together with other PAF-inhibitors of natural origin such as the flavonoids quercetin and luteolin, which have antiviral, anti-inflammatory, and anti-PAF actions.

Direct oral anticoagulant (DOAC) versus low-molecular-weight heparin (LMWH) for the treatment of cancer-associated thrombosis (which agent for which patient)

Venous thromboembolism (VTE) is a common complication among patients with cancer, associated with significant higher rate of mortality and morbidity. Low-molecular-weight heparin (LMWH) as a single therapeutic is considered as the standard of care for the treatment of acute cancer-associated thrombosis for many years, showing a significant 40% reduction of recurrent VTE (RR: 0.58; 95% CI, 0.43 - 0.77) without a significant increase of major bleeding complications compared to VKA (RR: 1.09; 95% CI 0.55 - 2.12). Based on results analysis studies only including patients with proximal DVT or PE the risk of recurrent VTE was similar in the DOAC and the LMWH (RR 0.68; 95% CI, 0.39 - 1.17) groups, without significantively increasing the risk of either major bleeding (RR = 1.32; 95% CI 0.7 - 2.47) or CRNMB (RR 1.6; 95% 0.99 - 2.6). Compared with LMWH, the risk of major bleeding and clinically relevant-non major bleeding was higher, although non-significantly, with DOACs than with LMWH, underlying that DOACs should be avoided in patients at high risk of bleeding. The higher risk of bleeding reported in DOACs-treated patients appears related to an excess of upper GI bleeding. In addition to GI cancer, other high-risk features associated with bleeding complications are an urothelial cancer, drug-drug interactions and use of anticancer drugs associated with GI toxicity. Overall, DOACs are an effective treatment option, and safe in most cancer patients with acute VTE. Nonetheless, DOACs should be used with caution in cancer patients at high risk for bleeding due to cancer site and stage per se or to cancer treatments.

COVID-19-Associated Coagulopathy and Inflammatory Response: What Do We Know Already and What Are the Knowledge Gaps?

Patients with coronavirus disease 2019 (COVID-19) frequently experience a coagulopathy associated with a high incidence of thrombotic events leading to poor outcomes. Here, biomarkers of coagulation (such as D-dimer, fibrinogen, platelet count), inflammation (such as interleukin-6), and immunity (such as lymphocyte count) as well as clinical scoring systems (such as sequential organ failure assessment [SOFA], International Society on Thrombosis and Hemostasis disseminated intravascular coagulation [ISTH DIC], and sepsis-induced coagulopathy [SIC] score) can be helpful in predicting clinical course, need for hospital resources (such as intensive care unit [ICU] beds, intubation and ventilator therapy, and extracorporeal membrane oxygenation [ECMO]) and patient's outcome in patients with COVID-19. However, therapeutic options are actually limited to unspecific supportive therapy. Whether viscoelastic testing can provide additional value in predicting clinical course, need for hospital resources and patient's outcome or in guiding anticoagulation in COVID-19-associated coagulopathy is still incompletely understood and currently under investigation (eg, in the rotational thromboelastometry analysis and standard coagulation tests in hospitalized patients with COVID-19 [ROHOCO] study). This article summarizes what we know already about COVID-19-associated coagulopathy and-perhaps even more importantly-characterizes important knowledge gaps.

Anticoagulation outcomes in hospitalized Covid-19 patients: A systematic review and meta-analysis of case-control and cohort studies

Background: Coagulopathy and thromboembolic events are common in Covid‐19 patients and are poor prognostic factors. Controversy exists regarding the potential of anticoagulation (AC) to reduce mortality and incidence of thromboembolic events in Covid‐19 patients. The current systematic review and meta‐analysis investigated the association between anticoagulants and mortality in adult hospitalized COVID‐19 patients using the available published non‐randomized studies. Methods: Google Scholar, PubMed, Scopus, the Cochrane Library and Clinical Trials.gov were searched for relevant studies. A meta‐analysis of adjusted and unadjusted estimates was performed. The relative risk was used as a measure of effect. The random‐effects model was used to pool estimates using the generic inverse variance method. Results: Sixteen studies were included in the quantitative data synthesis. Results showed a statistically significant association between AC and mortality (RR = 0.56, 95% CI 0.36; 0.92, p = 0.02). Both therapeutic (Relative risk [RR] = 0.4, 95% CI 0.27; 0.57) and prophylactic AC (RR = 0.54, 95% CI 0.41; 0.71) were associated with lower risk of mortality. Pre‐admission AC was not associated with mortality (RR = 0.84, 95% CI 0.49; 1.43, p > 0.05) while prophylactic AC was associated with higher risk of mortality compared to therapeutic AC (RR = 1.58, 95% CI 1.34; 1.87, p < 0.001). Conclusion: Findings support the association of AC with mortality in Covid‐19 patients. The results, synthesized from mostly low‐quality studies, show that prophylactic and therapeutic AC might reduce mortality in Covid‐19 patients. Findings suggest that therapeutic doses might be associated with better survival compared to prophylactic doses.

A higher D-dimer threshold for predicting pulmonary embolism in patients with COVID-19: a retrospective study

Purpose

COVID-19 raises D-dimer (DD) levels even in the absence of pulmonary embolism (PE), resulting in an increase in computed tomography pulmonary angiogram (CTPA) requests. Our purpose is to determine whether there are differences between DD values in PE-positive and PE-negative COVID-19 patients and, if so, to establish a new cutoff value which accurately determines when a CTPA is needed.

Methods

This study retrospectively analyzed all COVID-19 patients who underwent a CTPA due to suspected PE between March 1 and April 30, 2020, at Ramón y Cajal University Hospital, Madrid (Spain). DD level comparisons between PE-positive and PE-negative groups were made using Student’s t test. The optimal DD cutoff value to predict PE risk in COVID-19 patients was calculated in the ROC curve.

Results

Two hundred forty-two patients were included in the study. One hundred fifty-one (62%) were men and the median age was 68 years (IQR 55–78). An increase of DD (median 3260; IQR 1203–9625 ng/mL) was detected in 205/242 (96%) patients. 73/242 (30%) of the patients were diagnosed with PE on CTPA. The DD median value was significantly higher (p < .001) in the PE-positive group (7872, IQR 3150–22,494 ng/mL) compared with the PE-negative group (2009, IQR 5675–15,705 ng/mL). The optimal cutoff value for DD to predict PE was 2903 ng/mL (AUC was 0.76 [CI 95% 0.69–0.83], sensitivity 81%). The overall mortality rate was 16% (39/242).

Conclusion

A higher threshold (2903 ng/mL) for D-dimer could predict the risk of PE in COVID-19 patients with a sensitivity of 81%.

Rate of venous thromboembolism in a prospective all-comers cohort with COVID-19

COVID-19 is associated with a variety of clinical complications including coagulopathy, which frequently results in venous thromboembolism (VTE). Retrospective analyses reported a markedly increased rate of VTEs in COVID-19. However, most recent studies on coagulopathy in COVID-19 were only focused on critically ill patients, and without suitable control groups. We aimed to evaluate the rate of VTEs in an all-comers cohort with suspected COVID-19 during a 30-days follow-up period. We also studied the level of D-dimers and their association with the course of disease. In our prospective single-center study (DRKS00021206, 03/30/2020), we analyzed 190 patients with suspected COVID-19 admitted to the emergency department between March and April 2020. Forty-nine patients were SARS-CoV-2 positive (25.8%). The 141 SARS-CoV-2-negative patients served as control group. After completion of a 30-days follow-up, VTE was diagnosed in 3 patients of the SARS-CoV-2-positive group (6.1%, amongst these 2 ICU cases) versus 5 patients in the SARS-CoV-2-negative group (3.5%), however the difference was not statistically significant (p = 0.427). 30-days mortality was similar in both groups (6.1% vs. 5%, p = 0.720). Disease severity correlated with the maximum level of D-dimers during follow-up in COVID-19. The rate of VTE was numerically higher in SARS-CoV-2 positive all-comers presenting with suspected COVID-19 as compared to well-matched controls suffering from similar symptoms. VTEs in the COVID-19 group predominantly occurred in ICU courses. The maximum level of D-dimers during follow-up was associated with disease severity in COVID-19, whereas the level of D-dimers at admission was not.

Thromboinflammation in COVID-19 acute lung injury

Since the initial description in 2019, the novel coronavirus SARS-Cov-2 infection (COVID-19) pandemic has swept the globe. The most severe form of the disease presents with fever and shortness of breath, which rapidly deteriorates to respiratory failure and acute lung injury (ALI). COVID-19 also presents with a severe coagulopathy with a high rate of venous thromboembiolism. In addition, autopsy studies have revealed co-localized thrombosis and inflammation, which is the signature of thromboinflammation, within the pulmonary capillary vasculature. While the majority of published data is on adult patients, there are parallels to pediatric patients. In our experience as a COVID-19 epicenter, children and young adults do develop both the coagulopathy and the ALI of COVID-19. This review will discuss COVID-19 ALI from a hematological perspective with discussion of the distinct aspects of coagulation that are apparent in COVID-19. Current and potential interventions targeting the multiple thromboinflammatory mechanisms will be discussed.

Incidence of venous thromboembolism in hospitalized patients with COVID-19

BACKGROUND

Coronavirus disease 2019 (COVID-19) can lead to systemic coagulation activation and thrombotic complications.

OBJECTIVES

To investigate the incidence of objectively confirmed venous thromboembolism (VTE) in hospitalized patients with COVID-19.

METHODS

Single-center cohort study of 198 hospitalized patients with COVID-19.

RESULTS

Seventy-five patients (38%) were admitted to the intensive care unit (ICU). At time of data collection, 16 (8%) were still hospitalized and 19% had died. During a median follow-up of 7 days (IQR, 3-13), 39 patients (20%) were diagnosed with VTE of whom 25 (13%) had symptomatic VTE, despite routine thrombosis prophylaxis. The cumulative incidences of VTE at 7, 14 and 21 days were 16% (95% CI, 10-22), 33% (95% CI, 23-43) and 42% (95% CI 30-54) respectively. For symptomatic VTE, these were 10% (95% CI, 5.8-16), 21% (95% CI, 14-30) and 25% (95% CI 16-36). VTE appeared to be associated with death (adjusted HR, 2.4; 95% CI, 1.02-5.5). The cumulative incidence of VTE was higher in the ICU (26% (95% CI, 17-37), 47% (95% CI, 34-58), and 59% (95% CI, 42-72) at 7, 14 and 21 days) than on the wards (any VTE and symptomatic VTE 5.8% (95% CI, 1.4-15), 9.2% (95% CI, 2.6-21), and 9.2% (2.6-21) at 7, 14, and 21 days).

CONCLUSIONS

The observed risk for VTE in COVID-19 is high, particularly in ICU patients, which should lead to a high level of clinical suspicion and low threshold for diagnostic imaging for DVT or PE. Future research should focus on optimal diagnostic and prophylactic strategies to prevent VTE and potentially improve survival.

Clinical findings, risk factors, and final outcome in patients diagnosed with pulmonary thromboembolism and COVID-19 in hospital emergency departments

OBJECTIVES

To analyze clinical, laboratory, and radiologic findings and final health outcomes in patients with pulmonary embolism and coronavirus disease 2019 (COVID-19). To compare them to findings and outcomes in patients with pulmonary embolism without COVID-19.

MATERIAL AND METHODS

Multicenter, observational, retrospective study in 4 Spanish hospital emergency departments (EDs) from January 15 to April 15, 2020. Cases were located by reviewing all ED requests for pulmonary computed tomography angiography (CTA) procedures. Clinical, laboratory, and radiologic findings; medical histories and comorbidity; risk factors; and outcomes were compared between the 2 groups of patients (with or without COVID-19).

RESULTS

A total of 399 CTAs were ordered; 88 pulmonary embolisms were diagnosed, 28 of them (32%) in patients with COVID-19. This group had more men, and a history of thromboembolic disease was more common. We found no between-group differences in clinical presentation, laboratory, or radiologic findings; nor were there differences in final outcomes. In-hospital mortality was 7% (2 cases) in patients with COVID-19 and 17% (10 cases) in patients without the virus (odds ratio for death in patients with pulmonary embolism and COVID-19, 0.38; 95% CI, 0.08-1.89).

CONCLUSION

We found no clinically important differences in the clinical, laboratory, or radiologic findings between patients with or without COVID-19 who were treated for pulmonary embolism in our hospital EDs. Final outcomes also did not differ.

High incidence of venous thromboembolic events in anticoagulated severe COVID-19 patients

BACKGROUND

Coagulopathy is a common abnormality in patients with COVID-19. However, the exact incidence of venous thromboembolic event is unknown in anticoagulated, severe COVID-19 patients.

OBJECTIVES

Systematic assessment of venous thromboembolism (VTE) using complete duplex ultrasound (CDU) in anticoagulated COVID-19 patients.

PATIENTS AND METHODS

We performed a retrospective study in 2 French intensive care units (ICU) where CDU is performed as a standard of care. A CDU from thigh to ankle at selected sites with Doppler waveforms and images was performed early during ICU stay in patients admitted with COVID-19. Anticoagulation dose was left to the discretion of the treating physician based on the individual risk of thrombosis. Patients were classified as treated with prophylactic anticoagulation or therapeutic anticoagulation. Pulmonary embolism was systematically searched in patients with persistent hypoxemia or secondary deterioration.

RESULTS

From March 19 to April 11, 2020, 26 consecutive patients with severe COVID-19 were screened for VTE. Eight patients (31%) were treated with prophylactic anticoagulation, whereas 18 patients (69%) were treated with therapeutic anticoagulation. The overall rate of VTE in patients was 69%. The proportion of VTE was significantly higher in patients treated with prophylactic anticoagulation when compared with the other group (100% vs 56%, respectively, P = .03). Surprisingly, we found a high rate of thromboembolic events in COVID-19 patients treated with therapeutic anticoagulation, with 56% of VTE and 6 pulmonary embolisms.

CONCLUSION

Our results suggest considering both systematic screening of VTE and early therapeutic anticoagulation in severe ICU COVID-19 patients.

Prognostic role of the preoperative neutrophil-to-lymphocyte ratio and albumin for 30-day mortality in patients with postoperative acute pulmonary embolism

BACKGROUND

This retrospective study aimed to investigate the prognostic value of the neutrophil-to-lymphocyte ratio (NLR) and albumin for 30-day mortality in patients with postoperative acute pulmonary embolism (PAPE).

METHODS

We retrospectively reviewed the medical records of 101 patients with PAPE admitted from September 1, 2012, to March 31, 2019. The characteristics, surgical information, admission examination data and mortality within 30 days after PAPE were obtained from our electronic medical recording system and follow-up. The associations between the NLR, PLR, and other predictors and 30-day mortality were analyzed with univariate and multivariate analyses. Then, the nomogram including the independent predictors was established and evaluated.

RESULTS

Twenty-four patients died within 30 days, corresponding to a 30-day mortality rate of 23.8%. The results of the multivariate analysis indicated that both the NLR and albumin were independent predictors for 30-day mortality in patients with PAPE. The probability of death increased by approximately 17.1% (OR = 1.171, 95% CI: 1.073-1.277, P = 0.000) with a one-unit increase in the NLR, and the probability of death decreased by approximately 15.4% (OR = 0.846, 95% CI: 0.762c-0.939, P = 0.002) with a one-unit increase in albumin. The area under the curve of the nomogram was 0.888 (95% CI: 0.812-0.964).

CONCLUSION

Our findings showed that an elevated NLR and decreased albumin were related to poor prognosis in patients with PAPE. The NLR and albumin were independent prognostic factors for PAPE.

Myeloproliferative Diseases as Possible Risk Factor for Development of Chronic Thromboembolic Pulmonary Hypertension-A Genetic Study

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare disease which is often caused by recurrent emboli. These are also frequently found in patients with myeloproliferative diseases. While myeloproliferative diseases can be caused by gene defects, the genetic predisposition to CTEPH is largely unexplored. Therefore, the objective of this study was to analyse these genes and further genes involved in pulmonary hypertension in CTEPH patients. A systematic screening was conducted for pathogenic variants using a gene panel based on next generation sequencing. CTEPH was diagnosed according to current guidelines. In this study, out of 40 CTEPH patients 4 (10%) carried pathogenic variants. One patient had a nonsense variant (c.2071A>T p.Lys691*) in the BMPR2 gene and three further patients carried the same pathogenic variant (missense variant, c.1849G>T p.Val617Phe) in the Janus kinase 2 (JAK2) gene. The latter led to a myeloproliferative disease in each patient. The prevalence of this JAK2 variant was significantly higher than expected (p < 0.0001). CTEPH patients may have a genetic predisposition more often than previously thought. The predisposition for myeloproliferative diseases could be an additional risk factor for CTEPH development. Thus, clinical screening for myeloproliferative diseases and genetic testing may be considered also for CTEPH patients.

Characteristics of Acute Pulmonary Embolism in Patients With COVID-19 Associated Pneumonia From the City of Wuhan

The aim of this study was to describe clinical, imaging, and laboratory features of acute pulmonary embolism (APE) in patients with COVID-19 associated pneumonia. Patients with COVID-19 associated pneumonia who underwent a computed tomography pulmonary artery (CTPA) scan for suspected APE were retrospectively studied. Laboratory data and CTPA images were collected. Imaging characteristics were analyzed descriptively. Laboratory data were analyzed and compared between patients with and without APE. A series of 25 COVID-19 patients who underwent CTPA between January 2020 and February 2020 were enrolled. The median D-dimer level founded in these 25 patients was 6.06 μg/mL (interquartile range [IQR] 1.90-14.31 μg/mL). Ten (40%) patients with APE had a significantly higher level of D-dimer (median, 11.07 μg/mL; IQR, 7.12-21.66 vs median, 2.44 μg/mL; IQR, 1.68-8.34, respectively, P = .003), compared with the 15 (60%) patients without APE. No significant differences in other laboratory data were found between patients with and without APE. Among the 10 patients with APE, 6 (60%) had a bilateral pulmonary embolism, while 4 had a unilateral embolism. The thrombus-prone sites were the right lower lobe (70%), the left upper lobe (60%), both upper lobe (40%) and the right middle lobe (20%). The thrombus was partially or completely absorbed after anticoagulant therapy in 3 patients who underwent a follow-up CTPA. Patients with COVID-19 associated pneumonia have a risk of developing APE during the disease. When the D-dimer level abnormally increases in patients with COVID-19 pneumonia, CTPA should be performed to detect and assess the severity of APE.

Opportunistic Diagnosis of Extensive Pulmonary Embolus Following "COVID-19 Blood Battery" in Very Frail Older Patients

D-dimer is routinely measured to exclude the diagnosis of venous thromboembolism and is its main biomarker. Appropriate age-adjusted D-dimer testing improves D-dimer specificity, could decrease inappropriate CT pulmonary angiograms in the older person, and prevent unnecessary radiation exposure. A "COVID-19 blood battery", designed to increase the efficiency of evaluation of COVID-19 suspected patients is used in our institution. It includes D-dimers which are elevated in COVID-19 infections and potentially an index of severe infection. These 3 very frail patients presented late to the emergency department, all acutely and non-specifically unwell, with high prevalence of comorbidities and were transferred in by ambulance. They were triaged to the COVID-19 pathway of our hospital, and subsequently had negative COVID-19 swabs. All had an incidental finding of markedly elevated D-dimers, with potential causes of their symptoms other than pulmonary embolus. They were transferred to an acute geriatric ward specifically designated to manage older patients (>75years) who had negative nasopharyngeal swab results. They were all ultimately diagnosed with extensive pulmonary emboli with evidence of raised pulmonary pressures on CTPA and/or echocardiogram. It is possible that these patients had false negative COVID-19 swabs. Allowing for the novel nature of COVID-19, prospective evaluation for new symptoms and complications such as thromboembolic disease in those affected by milder symptoms should be considered. In the absence of clinical improvement following treatment of other conditions in frail older patients, D-dimer testing could be indicated with pursuit of specific diagnostic evaluation for venous thromboembolism when significantly elevated.

Diagnosis of Pulmonary Embolism with d-Dimer Adjusted to Clinical Probability

BACKGROUND

Retrospective analyses suggest that pulmonary embolism is ruled out by a d-dimer level of less than 1000 ng per milliliter in patients with a low clinical pretest probability (C-PTP) and by a d-dimer level of less than 500 ng per milliliter in patients with a moderate C-PTP.

METHODS

We performed a prospective study in which pulmonary embolism was considered to be ruled out without further testing in outpatients with a low C-PTP and a d-dimer level of less than 1000 ng per milliliter or with a moderate C-PTP and a d-dimer level of less than 500 ng per milliliter. All other patients underwent chest imaging (usually computed tomographic pulmonary angiography). If pulmonary embolism was not diagnosed, patients did not receive anticoagulant therapy. All patients were followed for 3 months to detect venous thromboembolism.

RESULTS

A total of 2017 patients were enrolled and evaluated, of whom 7.4% had pulmonary embolism on initial diagnostic testing. Of the 1325 patients who had a low C-PTP (1285 patients) or moderate C-PTP (40 patients) and a negative d-dimer test (i.e., <1000 or <500 ng per milliliter, respectively), none had venous thromboembolism during follow-up (95% confidence interval [CI], 0.00 to 0.29%). These included 315 patients who had a low C-PTP and a d-dimer level of 500 to 999 ng per milliliter (95% CI, 0.00 to 1.20%). Of all 1863 patients who did not receive a diagnosis of pulmonary embolism initially and did not receive anticoagulant therapy, 1 patient (0.05%; 95% CI, 0.01 to 0.30) had venous thromboembolism. Our diagnostic strategy resulted in the use of chest imaging in 34.3% of patients, whereas a strategy in which pulmonary embolism is considered to be ruled out with a low C-PTP and a d-dimer level of less than 500 ng per milliliter would result in the use of chest imaging in 51.9% (difference, -17.6 percentage points; 95% CI, -19.2 to -15.9).

CONCLUSIONS

A combination of a low C-PTP and a d-dimer level of less than 1000 ng per milliliter identified a group of patients at low risk for pulmonary embolism during follow-up. (Funded by the Canadian Institutes of Health Research and others; PEGeD ClinicalTrials.gov number, NCT02483442.).

Suppression of Human Platelet Activation via Integrin αIIbβ3 Outside-In Independent Signal and Reduction of the Mortality in Pulmonary Thrombosis by Auraptene

Auraptene is the most abundant coumarin derivative from plants. The pharmacological value of this compound has been well demonstrated, especially in the prevention of cancer and neurodegenerative diseases. Platelet activation is a major factor contributing to arterial thrombosis. Thus, this study evaluated the influence of auraptene in platelet aggregation and thrombotic formation. Auraptene inhibited platelet aggregation in human platelets stimulated with collagen only. However, auraptene was not effective in inhibiting platelet aggregation stimulated with thrombin, arachidonic acid, and U46619. Auraptene also repressed ATP release, [Ca²⁺]i mobilization, and P-selectin expression. Moreover, it markedly blocked PAC-1 binding to integrin α_IIbβ₃. However, it had no influence on properties related to integrin α_IIbβ₃-mediated outside-in signaling, such as the adhesion number, spreading area of platelets, and fibrin clot retraction. Auraptene inhibited the phosphorylation of Lyn-Fyn-Syk, phospholipase Cγ2 (PLCγ2), protein kinase C (PKC), Akt, and mitogen-activated protein kinases (MAPKs; extracellular-signal-regulated kinase (ERK1/2), and c-Jun N-terminal kinase (JNK1/2), but not p38 MAPK). Neither SQ22536, an adenylate cyclase inhibitor, nor ODQ, a guanylate cyclase inhibitor, reversed the auraptene-mediated inhibition of platelet aggregation. Auraptene reduced mortality caused by adenosine diphosphate (ADP)-induced pulmonary thromboembolism. In conclusion, this study provides definite evidence that auraptene signifies a potential therapeutic agent for preventing thromboembolic disorders.

Extended treatment with edoxaban in cancer patients with venous thromboembolism: A post-hoc analysis of the Hokusai-VTE Cancer study

BACKGROUND

Patients with active cancer and venous thromboembolism (VTE) are at high risk of recurrence. Therefore, continued anticoagulant therapy beyond the initial 6 months is suggested in this patient population, but evidence supporting this approach is limited.

METHODS

The Hokusai VTE Cancer trial compared edoxaban with dalteparin for VTE treatment in patients with active cancer. This post hoc analysis focused on the follow-up period from 6 to 12 months. The primary outcome was the composite of adjudicated first recurrent VTE or major bleeding. Secondary outcomes included recurrent VTE, major bleeding, and clinically relevant bleeding.

RESULTS

Of the 522 and 524 patients randomized to edoxaban or dalteparin, 294 (56%) received edoxaban and 273 (52%) received dalteparin for more than 6 months (median duration of 318 and 211 days, respectively). Between 6 and 12 months, the primary outcome during study treatment occurred in seven patients (2.4%) in the edoxaban group and six patients (2.2%) in the dalteparin group (unadjusted hazard ratio 1.05; 95% confidence interval, 0.36-3.05). Recurrent VTE occurred in two patients (0.7%) in the edoxaban group and in three patients (1.1%) in the dalteparin group, whereas major bleeding occurred in 5 (1.7%) and three patients (1.1%), respectively.

CONCLUSIONS

The rates of recurrent VTE or major bleeding are relatively low among patients with active cancer receiving extended anticoagulant therapy beyond 6 months. Extended treatment with oral edoxaban appears as effective and safe as subcutaneous dalteparin.

Arterial and venous thrombosis by high platelet count and high hematocrit: 108 521 individuals from the Copenhagen General Population Study

BACKGROUND

It is unclear whether high platelet count or high hematocrit predict risk of thrombosis in individuals from the general population.

OBJECTIVES

We tested the hypothesis that individuals from the general population with high platelet count or high hematocrit have high risk of arterial and venous thrombosis.

METHODS

We prospectively followed 108 521 individuals from The Copenhagen General Population Study for a median of 8 years. Platelet count and blood hematocrit were measured at study entry.

RESULTS AND CONCLUSION

Multivariable adjusted hazard ratios for individuals with platelet counts in the top 5 percentiles (>398 × 109 /L) vs in the 25th-75th percentiles (231-316 × 109 /L) were 1.77 (95% confidence interval [CI], 1.38-2.24) for arterial thrombosis in the brain (38 and 26 events/10 000 person-years) and 0.82 (95%, 0.61-1.11) for arterial thrombosis in the heart (23 and 28 events/10 000 person-years). For individuals with hematocrit values in the top 5 percentiles (women/men: >45/>48%) vs the 25th-75th percentiles (women/men: 38.1-42/41.1-45%), hazard ratios were 1.27 (95% CI, 0.91-1.75) for arterial thrombosis in the brain (40 and 26 events/10 000 person-years) and 1.46 (95% CI, 1.06-2.00) for arterial thrombosis in the heart (43 and 25 events/10 000 person-years). Neither high platelet count nor high hematocrit was associated with risk of venous thromboembolism. When excluding individuals with myeloproliferative neoplasia from the main analyses, results on risk of thrombosis were similar. In this prospective study, high platelet counts were associated with 1.8-fold risk of arterial thrombosis in the brain, whereas high hematocrit was associated with 1.5-fold risk of arterial thrombosis in the heart.