1. Department of Emergency Medicine, Center for Vascular Emergencies Massachusetts General Hospital, Harvard Medical School Boston Massachusetts USA
2. Department of Emergency Medicine, Kaiser Permanente Division of Research and the CREST Network, Oakland, CA Kaiser Permanente Roseville Medical Center Roseville California USA
3. Department of Emergency Medicine, Richard L. Roudebush VAMC Indiana University School of Medicine Indianapolis Indiana USA
4. Division of Hematology Department of Medicine Massachusetts General Hospital, Harvard Medical School Boston Massachusetts USA
5. Department of Emergency Medicine Thomas Jefferson University Hospitals Philadelphia Pennsylvania USA
6. Department of Emergency Medicine Indiana University School of Medicine Indianapolis Indiana USA
7. Department of Emergency Medicine Denver Health and University of Colorado School of Medicine Denver Colorado USA