Effect of remote ischaemic conditioning on platelet aggregation and platelet turnover.

Remote ischaemic conditioning (RIC) is a new beneficial treatment for patients with ST-elevation myocardial infarction. RIC may inhibit thrombus formation and, therefore, we investigated whether RIC affects platelet aggregation and turnover. 30 healthy male volunteers were subjected to intervention on day 1 (sham intervention, no aspirin), day 2 (RIC, no aspirin), and day 16 (RIC, treated 7 days with aspirin 75 mg/day). RIC was performed as four cycles of 5 min interchangeable inflation and deflation using an automated cuff. Blood samples were collected 5 min before, as well as 5 and 45 min after RIC. Platelet aggregation was measured by Multiplate® using collagen (COLtest), adenosine diphosphate (ADPtest), and arachidonic acid (ASPItest) as agonists. Platelet turnover was evaluated by flow cytometry. Serum thromboxane B2 was determined by ELISA to confirm aspirin compliance. We found no significant change in platelet aggregation at visit 1 (COLtest: p = 0.32; ADPtest: p = 0.24; ASPItest: p = 0.07), visit 2, except for ADP-induced platelet aggregation evaluated 5 min after RIC (COLtest: p = 0.39; ADPtest: p = 0.02; ASPItest: p = 0.39), or visit 3 (COLtest: p = 0.48; ADPtest: p = 0.61; ASPItest: p = 0.90). Platelet turnover was not influenced by RIC, neither on nor off aspirin (all p-values > 0.07). (1) RIC did not affect platelet aggregation in healthy young men. (2) RIC did not affect platelet turnover in healthy young men. (3) Aspirin did not influence the effect of RIC on platelet aggregation and turnover. (4) Future studies exploring the effect of RIC on platelet aggregation and turnover in patients with ischaemic heart disease are warranted.

Case report: Evolution of pulmonary manifestations and virological markers in critical COVID-19 infection in Bruton's agammaglobulinemia.

Despite several reports and small case series on the disease course of SARS-CoV-2 infection in patients with inborn errors of immunity (IEI), including X-linked agammaglobulinemia (XLA), this topic remains incompletely described. Here we present the case of a 38-year-old unvaccinated man with XLA, who acquired SARS-CoV-2 infection and experienced a protracted disease course with 47 days of SARS-CoV-2 positivity, critical COVID-19 with respiratory insufficiency necessitating intensive care and ventilatory support, and prompting repeated intensified treatments with remdesivir, dexamethasone, and monoclonal antibodies to eventually control infection. We describe the disease course and treatment and review the current literature on COVID-19 susceptibility and evidence for vaccine efficacy in patients with XLA.

Concerns, attitudes, and intended practices of Caribbean healthcare workers concerning COVID-19 vaccination: A cross-sectional study.

BACKGROUND: The Caribbean has a long history of being a global leader in immunization, and one factor contributing to this success has been the commitment of healthcare workers in promoting the benefits of vaccines. Healthcare workers play a critical role in building trust between the public and the immunization program and are generally cited as the most trusted source of information on vaccination. Healthcare workers themselves, therefore, must be confident in vaccination as a public health good and able to transmit this confidence to those who trust them. However, just as with the general public, healthcare workers develop confidence at different rates and may be susceptible to misinformation about vaccines. METHODS: During April and May 2021, the Pan American Health Organization (PAHO) conducted a mixed-methods survey to assess vaccination attitudes, opinions, and reasoning of 1197 healthcare workers across 14 Caribbean countries. FINDINGS: Seventy-seven percent of respondents expressed clear intention to be vaccinated for COVID-19 as soon as possible. Intention to be vaccinated as soon as possible was expressed by lower proportions of nurses (66%) and allied health professionals (62%) than physicians (85%) and by younger respondents than older ones (64% vs. 85%, respectively; p < 0.001 for all these comparisons). Across 32 questions about attitudes and opinions, vaccine hesitancy was consistently expressed by higher proportions of nurses and allied health professionals than physicians and by younger respondents than older ones. INTERPRETATION: Insights from the survey are helping PAHO address healthcare worker concerns with informative messages and supporting countries in policy development to increase vaccine confidence and coverage among Caribbean healthcare workers. FUNDING: This work has been sponsored by the World Health Organization/Pan American Health Organization, the Government of Germany and The Gavi Alliance.

Effect of remote ischaemic conditioning on coagulation and fibrinolysis.

INTRODUCTION: Remote ischaemic conditioning (RIC) reduces infarct size and may improve prognosis in patients with acute myocardial infarction. To explore the potential mechanisms, we investigated the effects of RIC on coagulation and fibrinolysis. METHODS: Interventional crossover study including 30 healthy drug-naïve males. Participants were exposed to a sham intervention (visit 1) and to RIC (visit 2 and 3) induced by intermittent arm ischaemia through four cycles of 5-min inflation of a blood pressure cuff followed by 5-min deflation. Prior to visit 3, all participants received aspirin 75mg daily for seven days. Blood samples were obtained at baseline as well as 5 and 45min after intervention. Whole blood coagulation was assessed by thromboelastometry (ROTEM®) and thrombin generation. Fibrinolysis was evaluated by clot turbidity-lysis, tissue plasminogen activator (t-PA), and plasminogen activator inhibitor-1 (PAI-1). RESULTS: No differences were found in clot initiation, clot propagation or clot strength evaluated by ROTEM® (all p-values≥0.98). During aspirin treatment, clot initiation and clot propagation decreased after RIC evaluated by ROTEM® EXTEM® clotting time (p=0.04) and ROTEM® EXTEM® maximum velocity (p=0.03). After sham and RIC, thrombin generation declined as evaluated by reduced endogenous thrombin potential (RIC: p=0.001) and peak (RIC: p=0.01). After RIC during aspirin treatment, changes in thrombin generation were inconsistent; increased peak (p=0.04) and time to peak (p<0.001) and a decrease in lag-time (p<0.001). Clot lysis time was prolonged both after sham and after RIC (p<0.001). After RIC, PAI-1 levels declined (p=0.03), but t-PA levels also declined after all interventions (p-values≤0.04). CONCLUSION: RIC did not have substantial effects on coagulation or fibrinolysis compared to sham. Overall, aspirin did not influence the results.