Participating centres represented by letters of support on this grant include; Duke University (Dr Ortel); University of Washington (Dr Wittkowsky); University of Massachusetts (Dr Becker); IRCCS Maggiore Hospital of Milano (Dr Moia); Centro Emostasi e Trombosi Reggio Emilia (Dr Silingardi); Instituti Ospitalieri di Cremona (Dr Testa and Alatri); Dr. Siragusa (Policlinico Palermo)