Coronavirus Disease 2019 (COVID-19), caused by the novel Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), has affected over 30 million globally to date. Although high rates of venous thromboembolism and evidence of COVID-19-induced endothelial dysfunction have been reported, the precise aetiology of the increased thrombotic risk associated with COVID-19 infection remains to be fully elucidated. Therefore, we assessed clinical platelet parameters and circulating platelet activity in patients with severe and nonsevere COVID-19. An assessment of clinical blood parameters in patients with severe COVID-19 disease (requiring intensive care), patients with nonsevere disease (not requiring intensive care), general medical in-patients without COVID-19, and healthy donors was undertaken. Platelet function and activity were also assessed by secretion and specific marker analysis. We demonstrated that routine clinical blood parameters including increased mean platelet volume (MPV) and decreased platelet:neutrophil ratio are associated with disease severity in COVID-19 upon hospitalisation and intensive care unit (ICU) admission. Strikingly, agonist-induced ADP release was 30- to 90-fold higher in COVID-19 patients compared with hospitalised controls and circulating levels of platelet factor 4 (PF4), soluble P-selectin (sP-selectin), and thrombopoietin (TPO) were also significantly elevated in COVID-19. This study shows that distinct differences exist in routine full blood count and other clinical laboratory parameters between patients with severe and nonsevere COVID-19. Moreover, we have determined all COVID-19 patients possess hyperactive circulating platelets. These data suggest abnormal platelet reactivity may contribute to hypercoagulability in COVID-19 and confirms the role that platelets/clotting has in determining the severity of the disease and the complexity of the recovery path.

Background Coronavirus disease 2019 (COVID-19), caused by novel coronavirus SARS-CoV-2, has to date affected over 13.3 million globally. Although high rates of venous thromboembolism and evidence of COVID-19-induced endothelial dysfunction have been reported, the precise aetiology of the increased thrombotic risk associated with COVID-19 infection remains to be fully elucidated. Objectives Here, we assessed clinical platelet parameters and circulating platelet activity in patients with severe and non-severe COVID-19. Methods An assessment of clinical blood parameters in patients with severe COVID-19 disease (requiring intensive care), patients with non-severe disease (not requiring intensive care), general medical in-patients without COVID-19 and healthy donors was undertaken. Platelet function and activity were also assessed by secretion and specific marker analysis. Results We show that routine clinical blood parameters including increased MPV and decreased platelet:neutrophil ratio are associated with disease severity in COVID-19 upon hospitalisation and intensive care unit admission. Strikingly, agonist-induced ADP release was dramatically higher in COVID-19 patients compared with non-COVID-19 hospitalized patients and circulating levels of PF4, sP-selectin and TPO were also significantly elevated in COVID-19. Conclusion Distinct differences exist in routine full blood count and other clinical laboratory parameters between patients with severe and non-severe COVID-19. Moreover, we have determined that COVID-19 patients possess hyperactive circulating platelets. These data suggest that abnormal platelet reactivity may contribute to hypercoagulability in COVID-19. Further investigation of platelet function in COVID-19 may provide additional insights into the aetiology of thrombotic risk in this disease and may contribute to the optimisation of thrombosis prevention and treatment strategies.

ObjectivesHomeless people lack a secure, stable place to live and experience higher rates of serious illness than the housed population. Studies, mainly from the USA, have reported increased use of unscheduled healthcare by homeless individuals.We sought to compare the use of unscheduled emergency department (ED) and inpatient care between housed and homeless hospital patients in a high-income European setting in Dublin, Ireland.SettingA large university teaching hospital serving the south inner city in Dublin, Ireland. Patient data are collected on an electronic patient record within the hospital.ParticipantsWe carried out an observational cross-sectional study using data on all ED visits (n=47 174) and all unscheduled admissions under the general medical take (n=7031) in 2015.Primary and secondary outcome measuresThe address field of the hospital’s electronic patient record was used to identify patients living in emergency accommodation or rough sleeping (hereafter referred to as homeless). Data on demographic details, length of stay and diagnoses were extracted.ResultsIn comparison with housed individuals in the hospital catchment area, homeless individuals had higher rates of ED attendance (0.16 attendances per person/annum vs 3.0 attendances per person/annum, respectively) and inpatient bed days (0.3 vs 4.4 bed days/person/annum). The rate of leaving ED before assessment was higher in homeless individuals (40% of ED attendances vs 15% of ED attendances in housed individuals). The mean age of homeless medical inpatients was 44.19 years (95% CI 42.98 to 45.40), whereas that of housed patients was 61.20 years (95% CI 60.72 to 61.68). Homeless patients were more likely to terminate an inpatient admission against medical advice (15% of admissions vs 2% of admissions in homeless individuals).ConclusionHomeless patients represent a significant proportion of ED attendees and medical inpatients. In contrast to housed patients, the bulk of usage of unscheduled care by homeless people occurs in individuals aged 25–65 years.

Background: Hypercoagulability and endothelial dysfunction are hallmarks of coronavirus disease 2019 (COVID-19) and appear to predict disease severity. A high incidence of thrombosis despite thromboprophylaxis is reported in patients with moderate to severe COVID-19. Recent randomized clinical trials suggest that therapeutic-intensity heparin confers a survival benefit in moderate-severity COVID-19 compared to standard-intensity heparin, potentially by harnessing heparin-mediated endothelialstabilizing and anti-inflammatory effects. Objective: We hypothesized that patients with moderate-severity COVID-19 exhibit enhanced hypercoagulability despite standard-intensity thromboprophylaxis with low molecular weight heparin (LMWH) compared to non-COVID-19 hospitalized patients. Methods: Patients with moderate COVID-19 and a control group (severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2]-negative hospitalized patients) receiving LMWH thromboprophylaxis were recruited. Markers of endothelial damage and plasma thrombin generation parameters were assessed. Results: Tissue plasminogen activator levels were significantly increased in the COVID-19 group (8.3 ± 4.4 vs. 4.9 ± 2.4 ng/ml; P = .02) compared to non-COVID-19-hospitalized patients. Despite thromboprophylaxis, mean endogenous thrombin potential was significantly increased among COVID-19 patients (1929 ± 448 vs. 1528 ± 460.8 nM*min; P = .04) but lag time to thrombin generation was significantly | 1009 KELLIHER Et aL.

To date, coronavirus disease 2019 (COVID-19) has affected over 100 million people globally. COVID-19 can present with a variety of different symptoms leading to manifestation of disease ranging from mild cases to a life-threatening condition requiring critical care-level support. At present, a rapid prediction of disease severity and critical care requirement in COVID-19 patients, in early stages of disease, remains an unmet challenge. Therefore, we assessed whether parameters from a routine clinical hematology workup, at the time of hospital admission, can be valuable predictors of COVID-19 severity and the requirement for critical care. Hematological data from the day of hospital admission (day of positive COVID-19 test) for patients with severe COVID-19 disease (requiring critical care during illness) and patients with non-severe disease (not requiring critical care) were acquired. The data were amalgamated and cleaned and modeling was performed. Using a decision tree model, we demonstrated that routine clinical hematology parameters are important predictors of COVID-19 severity. This proof-of-concept study shows that a combination of activated partial thromboplastin time, white cell count-to-neutrophil ratio, and platelet count can predict subsequent severity of COVID-19 with high sensitivity and specificity (area under ROC 0.9956) at the time of the patient's hospital admission. These data, pending further validation, indicate that a decision tree model with hematological parameters could potentially form the basis for a rapid risk stratification tool that predicts COVID-19 severity in hospitalized patients.

Pulmonary arterial hypertension (PAH) is a rare disease of the pulmonary vasculature, characterised pathologically by proliferation, remodelling and thrombosis in situ. Unfortunately, existing therapeutic interventions do not reverse these findings and the disease continues to result in significant morbidity and premature mortality. A number of haematological derangements have been described in PAH which may provide insights into the pathobiology of the disease and also provide opportunities to target new therapeutic pathways. These include quantitative and qualitative platelet abnormalities, such as thrombocytopaenia, increased mean platelet volume (MPV) and altered platelet bioenergetics. Furthermore, a hypercoagulable state and aberrant negative regulatory pathways can be observed, which could contribute to thrombosis in situ in distal pulmonary arteries and arterioles. Finally, there is increasing interest in the role of extracellular vesicle (EV) autocrine and paracrine signalling in PAH, and their potential utility as biomarkers and novel therapeutic targets. This review focuses on the potential role of platelets, EVs and coagulation pathways in the pathobiology of PAH. We highlight important unanswered clinical questions and the implications of these observations for future research and PAH directed therapies.

Pulmonary hypertension (PH) is a prevalent disease of the pulmonary vasculature that is characterised by considerable morbidity and mortality. Substantial efforts have been made in recent years to improve disease recognition, diagnosis and management, and this is reflected in current guidelines. The haemodynamic definition of PH has been revised and a definition for exercise PH has been provided. Risk stratification has been refined and the importance of comorbidities and phenotyping have been highlighted. These changes provide an opportunity to potentially identify pulmonary vascular disease at an earlier stage and to enhance patient-centred, goal-orientated treatment decisions. A promising fourth treatment pathway for pulmonary arterial hypertension and potential targeted therapies for group 3 PH are on the horizon, concepts which seemed inconceivable only a few years ago. Beyond medication, there is a greater appreciation for the importance of supervised training in stable PH and the possible role of interventional therapies in select cases. The landscape of PH is changing and it is characterised by progress, innovation and opportunities. In this article, we highlight some of the new trends in PH, with a specific focus on the revised European Society of Cardiology/European Respiratory Society 2022 guidelines for the diagnosis and management of PH.

Pulmonary Hypertension (PH) is a progressive cardiorespiratory disease, that is characterized by considerable morbidity and mortality. While physical activity (PA) can improve symptoms and quality of life, engagement in this population is suboptimal. The aim of this study was to explore attitudes towards exercise and the dimensions that influence PA participation in individuals with PH. Virtual, semi-structured interviews were conducted with individuals, with a formal diagnosis of PH. Participants were recruited through the Pulmonary Hypertension Association of Ireland. Interviews were transcribed and analysed using thematic analysis. Nineteen patients were interviewed (n=19). There was a female preponderance (n=13) and the mean age was 50 ± 12 years. Three themes were identified and included fear; perceived value of exercise; and environmental factors. Fear was the primary theme and included three sub-themes of fear of (i) over-exertion, (ii) physical damage and (iii) breathlessness. The perceived value of exercise encompassed two distinct sub-themes of perceived (i) exercise importance and (ii) benefits of exercise. Environmental factors included the terrain, weather conditions and location. Fear of overexertion, harm and dyspnoea strongly influenced attitudes to and engagement in PA. This study revealed heterogenous patient perspectives regarding the importance of PA and exercise. Future interventions that mitigate fear and promote the value of PA for individuals with PH may have considerable benefits in promoting PA engagement. Such interventions require multidisciplinary involvement, including specialised PH clinicians and exercise and behaviour change specialists.