1 Cardiovascular Division, Department of Medicine and Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, United States.
2 Servei de Bioquímica Clínica, Hospital de Sant Pau i Institut d'Investigacions Biomèdiques Sant Pau, Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Barcelona, Spain. Electronic address: Jordonez@santpau.es.