1. Venous Thromboembolism Unit, Internal Medicine Department, Hospital General Universitario Gregorio Marañón, Madrid, Spain;
2. School of Medicine, Universidad Complutense de Madrid, Madrid, Spain;
3. Research Division, Instituto de Investigaciones Sanitarias Gregorio Marañón, Madrid, Spain;
4. Department of Neuroscience, IRCCS - Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy;
5. Sandwell and West Birmingham Hospitals NHS Trust, Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, UK;
6. Department of Internal Medicine and Medical Specialties, Sapienza University of Rome, Rome, Italy;
7. Pulmonary Hypertension Centre, Thoraxclinic at Heidelberg University Hospital, Heidelberg, Germany