1. Internal Medicine Department, Hospital Universitario Clínico San Carlos, 28040 Madrid, Spain
2. School of Medicine, Universidad Complutense de Madrid, 28040 Madrid, Spain
3. Instituto de Investigación Sanitaria Hospital Clínico San Carlos, 28040 Madrid, Spain
4. Venous Thromboembolism Unit, Internal Medicine Department, Hospital General Universitario Gregorio Marañón, 28007 Madrid, Spain
5. Instituto de Investigación Sanitaria Gregorio Marañón, 28007 Madrid, Spain
6. School of Medicine, Universidad CEU San Pablo, 28668 Alcorcón, Spain