Editorial COVID-19 and Thrombosis 2023: New Waves of SARS-CoV-2 Infection, Triage Organization in Emergency Department and the Association of VOCs/VOI with Pulmonary Embolism.

Nearly two years ago, the SARS-CoV-2 outbreak began, and our lives have changed significantly since then [...].

Lesson Learnt by Covid-19: Going from Pandemic to Endemic Covid-19, should we Work for Diagnostic Criteria to Perform a Right Diagnosis of Covid-19 in the Future?

Patients with lung failure could be always easily identified because associated to typical signs and symptoms have anamnestic relevant data (e.g. immunocompromised patients or antivax people or non-responders to vaccines);yet also patients without recent clinical findings of lung failure may be found with interstitial pneumonia that should be investigated with a thorough differential diagnosis including also the research of SARS CoV2 on nasopharyngeal swab or bronchoalveolar lavage. Immunological tests as immunoglobulin's toward SARS CoV2 IG M or IG G have a positive clinical impact only if symptoms are longer than 5-6 days and in non-vaccinated people (in particular IG G). [...]in patients with high suspect of COVID-19radiological imaging of lung is always needed because the specific tropism of SARS CoV2 for respiratory system, in particular for the action of viral spike protein and its link with ACE2 protein present in high concentration on the surface of cells of respiratory tract. [...]these patients may induce clinical misunderstanding in daily clinical practice: they may refer a specific symptoms escaping each type of triage system, they may have a reduced or absent viral load so escaping real Time PCR at NPS and they may show not-extended interstitial pneumonia without recent infection and/or lung failure so inducing all of us to consider a thorough differential diagnosis with other causes of interstitial pneumonia. [...]after the exclusion of connettivitiis (e.g. rheumatoid arthritis, systemic erythematous lupus and so) [30] and hypersensitivity pneumonitis (e.g. drug intolerance, allergy and so on) [31, 32], an evaluation of infective causes should be performed and it should include the microbiological test to identify bacteria, pests or viruses (e.g. mycoplasma, legionellaspp, pneumocystis, influenza virus) [33, 34] and to include also the research of SARS CoV2 with NPS or bronchoalveolar lavage (BAL) with real time PCR (Table 1).

Special Issue "COVID-19 and Thrombosis".

Since the pandemic began, an association among COVID-19 and venous thromboembolism has been reported, in particular for inpatients [...].

Correction: Di Micco et al. Clinical Differences between COVID-19 and a COVID-like Syndrome. J. Clin. Med. 2021, 10, 2519.

Incorrect Affiliation [...].

Risk Factors of Venous Thromboembolism in Noncritically Ill Patients Hospitalized for Acute COVID-19 Pneumonia Receiving Prophylactic-Dose Anticoagulation.

Background: Therapeutic/intermediate-dose heparin reduces the risk of thromboembolic events but increases the risk of major bleeding in patients hospitalized for acute COVID-19 pneumonia. Objectives: To prospectively assess the incidence of objectively proven venous thromboembolism (VTE) and identify predisposing risk factors in a cohort of hospitalized patients with acute COVID-19 pneumonia undergoing prophylactic-dose heparin. Patients and methods: All consecutive patients admitted for acute COVID-19 pneumonia to the General Internal Medicine Unit of Padova University Hospital, Italy between November 2020 and April 2021, and undergoing prophylactic-dose heparin, were enrolled. Demographic and clinical characteristics and laboratory and radiological findings were recorded on admission. Cases were patients who developed VTE during their hospital stay. Univariable and multivariable logistic regression analyses were used to ascertain the risk factors associated with developing in-hospital VTE. Results: 208 patients (median age: 77 years; M/F 98/110) were included; 37 (18%) developed in-hospital VTE during a median follow-up of 10 days (IQR, 4-18). VTE patients were significantly younger (p = 0.004), more obese (p = 0.002), and had a lower Padua prediction score (p < 0.03) and reduced PaO2/FIO2 ratio (p < 0.03) vs. controls. Radiological findings of bilateral pulmonary infiltrates were significantly more frequent in VTE patients than controls (p = 0.003). Multivariable regression showed that obesity (1.75, 95% CI 1.02-3.36; p = 0.04) and bilateral pulmonary infiltrates on X-rays (2.39, 95% CI 1.22-5.69; p = 0.04) were correlated with increased risk of in-hospital VTE. Conclusions: Obesity and bilateral pulmonary infiltrates on imaging may help clinicians to identify patients admitted to medical wards for acute COVID-19 pneumonia at risk of developing VTE despite prophylactic-dose heparin. Further studies are needed to evaluate whether the administration of therapeutic/intermediate-dose heparin may help prevent VTE episodes without further increasing the bleeding risk.

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

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

Heparin and SARS-CoV-2: Multiple Pathophysiological Links.

Low molecular weight heparin, enoxaparin, has been one of most used drugs to fight the SARS-CoV-2 pandemic. Pharmacological properties of heparin recognize its specific ability, as with other oligosaccharides and glycosaminoglycan, to bind several types of viruses during their pass through the extracellular matrix of the respiratory tract, as well as its anticoagulant activity to prevent venous thromboembolism. Antithrombotic actions of enoxaparin have been testified both for inpatients with COVID-19 in regular ward and for inpatients in Intensive Care Units (ICUs). Prophylactic doses seem to be able to prevent venous thromboembolism (VTE) in inpatients in the regular ward, while intermediate or therapeutic doses have been frequently adopted for inpatients with COVID-19 in ICU. On the other hand, although we reported several useful actions of heparin for inpatients with COVID-19, an increased rate of bleeding has been recorded, and it may be related to several conditions such as underlying diseases with increased risks of bleeding, increased doses or prolonged administration of heparin, personal trend to bleed, and so on.

Pathophysiology of Vaccine-Induced Prothrombotic Immune Thrombocytopenia (VIPIT) and Vaccine-Induced Thrombocytopenic Thrombosis (VITT) and Their Diagnostic Approach in Emergency.

SARS-CoV-2 induced a pandemic that is reported to have started in Asia and was then extended to other countries in the world. Main clinical aspects of this viral infection have been lung injuries with severe pneumonia requiring prolonged hospitalization and associated morbidities such as venous thromboembolism and/or superinfection by bacteria, fungus or other pests. Immediately there was a need to develop a sustainable therapeutic strategy, such as vaccination. Vaccines against Covid-19, in fact, exert a protective action for common people and reduce viral diffusion. Yet, vaccination of a large number of people raises the question of a well-known complication of several types of vaccines; this complication is immune thrombocytopenia, which is sometimes associated with thrombosis as well. In this short review, we summarized mechanisms involved in the pathogenesis of vaccine-induced prothrombotic immune thrombocytopenia and vaccine-induced thrombocytopenic thrombosis.

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.

Clinical Differences between COVID-19 and a COVID-Like Syndrome.

COVID-19 is an infection due to SARS-CoV-2; this virus has been identified as the cause of the present pandemic. Several typical characteristics are present in this infection, in particular pneumonia with possible lung failure, but atypical clinical presentations are being described daily by physicians around the world. Ground-glass opacities with pneumonia are the most common and dangerous presentations of the COVID-19 disease, and they are usually associated with positive nasopharyngeal swab (NPS) tests with detectable SARS-CoV-2 viral RNA. Compared to the general population, hospital workers have been at a greater risk of infection ever since the first patients were hospitalized. However, hospital workers have also been reported as having COVID-like symptoms despite repeated negative swab tests but having tested positive for SARS-CoV-2 antibodies with serological tests. We can postulate that a COVID-like syndrome is possible, in particular in hospital workers, that is characterized by symptoms similar to those of COVID-19, but with repeated negative nasopharyngeal swabs. These repeated negative NSPs make the difference in daily clinical management with people that experienced a single false negative nasopharyngeal swab; furthermore, a clear clinical differentiation of these situations is still lacking in the literature. For this reason, here, we report our main findings from a cohort of patients with a COVID-like syndrome compared to a similar group affected by typical COVID-19.

COVID-19 and Venous Thromboembolism in Intensive Care or Medical Ward.

Despite thromboprophylaxis, patients with coronavirus disease 2019 (COVID-19) exhibit hypercoagulability and higher venous thromboembolic risk, although its real incidence is still unknown. The aim of this study was to evaluate the incidence of venous thromboembolism (VTE) in patients with COVID-19 admitted to both intensive care units (ICUs) and medical wards (MWs). Consecutive patients admitted for COVID-19 to the MW and the ICU at Padua University Hospital, all receiving thromboprophylaxis, underwent systematic ultrasonography of the internal jugular, and the upper and lower limbs veins every 7 days (± 1 day) after the admission; and, if negative, once-weekly until discharge or death. In case of suspected pulmonary embolism, a multidetector computed tomographic angiography was performed. The primary outcome was the proportion of any deep-vein thrombosis (DVT) and symptomatic pulmonary embolism in both groups. An extended blood coagulative test was performed as well. From March 4 to April 30, 2020, a total of 85 patients were investigated, 44 (52%) in MWs and 41 (48%) in the ICU. Despite thromboprophylaxis, VTE occurred in 12 patients in the MWs (27.3%) and 31 patients in the ICU (75.6%) with an odds ratio of 9.3 (95% confidence interval (CI) 3.5-24.5; P < 0.001). Multiple-site DVT occurred in 55.6% of patients (95% CI 39.6-70.5). Increased D-dimer levels significantly correlated with VTE (P = 0.001) and death (P = 0.015). Summarizing, patients with COVID-19 admitted to the MW or ICU showed a high frequency of venous thromboembolism, despite standard-dose or high-dose thromboprophylaxis. Whether thrombosis, particularly asymptomatic events, may play a role in the morbidity and mortality of patients with COVID-19 remain to be clarified.