Introduction: The COVID-19 outbreak is having an impact on the well-being of healthcare workers. Mindfulness-based interventions have shown effectiveness in reducing stress and fostering resilience and recovery in healthcare workers. There are no studies examining the feasibility of brief mindfulness-based interventions during the COVID-19 outbreak. Materials and Methods: This is an exploratory study with a post intervention assessment. We describe an on-site brief mindfulness intervention and evaluate its helpfulness, safety, and feasibility. Results: One thousand out of 7,000 (14%) healthcare workers from La Paz University Hospital in Madrid (Spain) participated in at least one session. One hundred and fifty out of 1,000 (15%) participants filled out a self-report questionnaire evaluating the helpfulness of the intervention for on-site stress reduction. Ninety two subjects (61%) participated in more than one session. Most of the participants were women (80%) with a mean age of 38.6 years. Almost half of the sample were nurses (46%). Sessions were perceived as being helpful with a mean rating of 8.4 on a scale from 0 to 10. Only 3 people (2%) reported a minor adverse effect (increased anxiety or dizziness). Discussion: Our data supports the utility, safety and feasibility of an on-site, brief mindfulness-based intervention designed to reduce stress for frontline health workers during a crisis. There is a need to continue testing this type of interventions, and to integrate emotion regulation strategies as an essential part of health workers' general training. Clinical Trial Registration number: NCT04555005.

Background. - It is known that patients with COVID-19 are at increased risk of thrombosis. Although COVID-19 infection primarily affects the lower respiratory tract system, emerging reports suggest direct and indirect cardiovascular complications. However, the key mechanisms under thrombosis development at great arterial vessels are still unclear.Case presentation. – We report the cases of 4 patients who were admitted to our hospital and suffered from arterial thrombotic complications. All of them were older than 60 years and only 1 did not have cardiovascular risk factors. It should be noted that days prior to the diagnosis of arterial thrombosis, 3 of the 4 patients were under anticoagulant treatment. It is also interesting that in contrast to already known typical microvascular locations, our patients suffered from large arterial vessels thrombosis. Furthermore, none of them would present with severe respiratory symptoms. Conclusions. – The underlying mechanism of COVID-19-associated arterial thrombosis remains unclear and might be independent of the cytokine storm that occurs in patients with COVID-19-associated venous thrombosis. Also, the role of anti-platelets agents as prophylactic treatment in high-risk patients remains unclear. Multicenter clinical trials are necessary to clarify these issues.