Immunothrombosis: Molecular Aspects and New Therapeutic Perspectives.

Thromboinflammation or immunothrombosis is a concept that explains the existing link between coagulation and inflammatory response present in many situations, such as sepsis, venous thromboembolism, or COVID-19 associated coagulopathy. The purpose of this review is to provide an overview of the current data regarding the mechanisms involved in immunothrombosis in order to understand the new therapeutic strategies focused in reducing thrombotic risk by controlling the inflammation.

Síndrome de Trombosis con Trombocitopenia asociado a vacunas de adenovirus frente a la COVID-19: epidemiología y presentación clínica de la serie española Thrombosis with Thrombocytopenia Syndrome following adenovirus vector-based vaccines to prevent COVID-19: epidemiology and clinical presentation in Spain

Introducción: Se describen las características epidemiológicas y clínicas de los casos de síndrome de trombosis con trombocitopenia (STT) notificados en España. Métodos: Se incluyeron los casos de trombosis venosa o arterial con trombocitopenia tras recibir vacuna con vectores de adenovirus no replicantes frente a la COVID-19 (AstraZeneca y Janssen) del 1 de febrero al 26 de septiembre de 2021. Se describe la tasa de notificación, (número de casos notificados /número de dosis administradas), y el análisis de casos observados frente a esperados (O/E). Se evaluaron los predictores de mortalidad. Resultados: Se notificaron 61 casos, cumpliendo 45 los criterios de elegibilidad, 82% mujeres. La tasa de notificación global fue 4/1.000.000 dosis y 14-15/1.000.000 dosis entre los 30-49 años. El número de casos de trombosis de senos cerebrales observados fue 6-18 veces superior al esperado en menores de 49 años. Los síntomas comenzaron 10 (rango intercuartílico: 7-14) días tras la vacunación. El 80% (intervalo de confianza (IC) al 95%: 65-90%) tenía trombocitopenia en el momento de su visita a urgencias y el 65% (IC 95%: 49-78%) elevación del dímero D (> 2000 ng/mL). La trombosis fue de múltiples localizaciones en 36% y fatal en 24% de los pacientes. Un valor nadir de trombocitopenia < 50.000 /μL (odds ratio (OR): 7,4;IC95%: 1,2-47,5) y la presencia de hemorragia cerebral (OR: 7,9;IC95%: 1,3-47,0) se asociaron a un desenlace fatal. Conclusiones: Debe sospecharse el STT en pacientes que presenten síntomas unos 10 días tras la vacunación y presenten trombocitopenia y/o elevación de dímero D.

Venous Thrombosis within 30 Days after Vaccination against SARS-CoV-2 in a Multinational Venous Thromboembolism Registry.

BACKGROUND: Venous thromboembolism (VTE)-including deep vein thrombosis, pulmonary embolism, and cerebral venous sinus thrombosis (CVST)-may occur early after vaccination against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We sought to describe the site, clinical characteristics, and outcomes of VTE after vaccination against SARS-CoV-2. METHODS: In a prospective study using the Registro Informatizado de Enfermedad TromboEmbólica (RIETE) platform, patients with VTE 4-30 days after vaccination against SARS-CoV-2 (1 February 2021 through 30 April 2021) were included. VTE patients recruited from the same centers into RIETE in the same months in 2018-2019 were selected as the reference group. All-cause mortality and major bleeding were the main study outcomes. RESULTS: As of 30 April 2020, 102 patients with post-vaccination VTEs had been identified (28 after adenovirus-based vaccination [ChAdOx1 nCov-19; AstraZeneca] and 74 after mRNA-based vaccination [mRNA-1273; Moderna, and BNT162b2; Pfizer]). Compared with 911 historical controls, patients with VTE after adenovirus-based vaccination more frequently had CVST (10.7% vs. 0.4%, p < 0.001) or thrombosis at multiple sites (17.9% vs. 1.3%, p < 0.001), more frequently had thrombocytopenia (40.7% vs. 14.7%, p < 0.001), and had higher 14-day mortality (14.3% vs. 0.7%; odds ratio [OR]: 25.1; 95% confidence interval [CI]: 6.7-94.9) and major bleeding rates (10.3% vs. 1.0%, OR: 12.03, 95% CI: 3.07-47.13). The site of thrombosis, accompanying thrombocytopenia, and 14-day mortality rates were not significantly different for patients with VTE after mRNA-based vaccination, compared with historical controls. CONCLUSIONS: Compared with historical controls, VTE after adenovirus-based vaccination against SARS-CoV-2 is accompanied by thrombocytopenia, occurs in unusual sites, and is associated with worse clinical outcomes.

Therapeutic versus Prophylactic Bemiparin in Hospitalized Patients with Nonsevere COVID-19 Pneumonia (BEMICOP Study): An Open-Label, Multicenter, Randomized, Controlled Trial.

Thromboprophylaxis with low molecular weight heparin in hospitalized patients with COVID-19 is mandatory, unless contraindicated. Given the links between inflammation and thrombosis, the use of higher doses of anticoagulants could improve outcomes. We conducted an open-label, multicenter, randomized, controlled trial in adult patients hospitalized with nonsevere COVID-19 pneumonia and elevated D-dimer. Patients were randomized to therapeutic-dose bemiparin (115 IU/kg daily) versus standard prophylaxis (bemiparin 3,500 IU daily), for 10 days. The primary efficacy outcome was a composite of death, intensive care unit admission, need of mechanical ventilation support, development of moderate/severe acute respiratory distress, and venous or arterial thrombosis within 10 days of enrollment. The primary safety outcome was major bleeding (International Society on Thrombosis and Haemostasis criteria). A prespecified interim analysis was performed when 40% of the planned study population was reached. From October 2020 to May 2021, 70 patients were randomized at 5 sites and 65 were included in the primary analysis; 32 patients allocated to therapeutic dose and 33 to standard prophylactic dose. The primary efficacy outcome occurred in 7 patients (22%) in the therapeutic-dose group and 6 patients (18%) in the prophylactic-dose (absolute risk difference 3.6% [95% confidence interval [CI], -16% -24%]; odds ratio 1.26 [95% CI, 0.37-4.26]; p = 0.95). Discharge in the first 10 days was possible in 66 and 79% of patients, respectively. No major bleeding event was registered. Therefore, in patients with COVID-19 hospitalized with nonsevere pneumonia but elevated D-dimer, the use of a short course of therapeutic-dose bemiparin does not appear to improve clinical outcomes compared with standard prophylactic doses. Trial Registration: ClinicalTrials.gov NCT04604327.

PICO Questions and DELPHI Methodology for the Management of Venous Thromboembolism Associated with COVID-19.

Patients with coronavirus disease 2019 (COVID-19) have a higher risk of venous thromboembolic disease (VTE) than patients with other infectious or inflammatory diseases, both as macrothrombosis (pulmonar embolism and deep vein thrombosis) or microthrombosis. However, the use of anticoagulation in this scenario remains controversial. This is a project that used DELPHI methodology to answer PICO questions related to anticoagulation in patients with COVID-19. The objective was to reach a consensus among multidisciplinary VTE experts providing answers to those PICO questions. Seven PICO questions regarding patients with COVID-19 responded with a broad consensus: 1. It is recommended to avoid pharmacological thromboprophylaxis in most COVID-19 patients not requiring hospital admission; 2. In most hospitalized patients for COVID-19 who are receiving oral anticoagulants before admission, it is recommended to replace them by low molecular weight heparin (LMWH) at therapeutic doses; 3. Thromboprophylaxis with LMWH at standard doses is suggested for COVID-19 patients admitted to a conventional hospital ward; 4. Standard-doses thromboprophylaxis with LMWH is recommended for COVID-19 patients requiring admission to Intensive Care Unit; 5. It is recommended not to determine D-Dimer levels routinely in COVID-19 hospitalized patients to select those in whom VTE should be suspected, or as a part of the diagnostic algorithm to rule out or confirm a VTE event; 6. It is recommended to discontinue pharmacological thromboprophylaxis at discharge in most patients hospitalized for COVID-19; 7. It is recommended to withdraw anticoagulant treatment after 3 months in most patients with a VTE event associated with COVID-19. The combination of PICO questions and DELPHI methodology provides a consensus on different recommendations for anticoagulation management in patients with COVID-19.

Spanish Society of Hematology and Hemotherapy expert consensus opinion for SARS-CoV-2 vaccination in onco-hematological patients.

In the midst of the COVID-19 pandemic, different vaccines in front of SARS-CoV-2 have been approved and administered in different vulnerable populations. As patients with cancer were excluded from pivotal trials of vaccination, little is known on their immunogenic response to these vaccines, particularly in patients with severely impaired immune system. In response to that uncertainty, the Spanish Society of Hematology and Hemotherapy launched an initiative aimed to provide recommendations for vaccination of the main hematological conditions. This document is based on the available information on COVID-19 outcomes, prior knowledge on vaccination in hematological patients, recent published data on serological response in oncohematological patients and expert opinions. New information about SARS-CoV-2 vaccination will be gathered in the near future, providing new scientific grounds to delineate the most adequate management of vaccination in patients with hematological diseases. The current limited data on SARS-CoV-2 vaccines in hematological patients represents a major limitation of this expert consensus opinion. In fact, the speed in which this field evolves may reduce their validity in the near future.