Department of Dermatology, Hospital Universitario Ramon y Cajal, Madrid, Spain; Facultad de Medicina, Universidad Francisco de Vitoria, Madrid, Spain. National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA. The Department of Dermatology, The George Washington School of Medicine & Health Sciences, Washington, District of Columbia, USA. Department of Radiology, Gregorio Marañon Hospital, Madrid, Spain. Department of Radiology, University Hospital San Cecilio, Granada, Spain. Department of Dermatology, Complejo Hospitalario de Toledo, Toledo, Spain. Department of Dermatology, Hospital Universitario Ramon y Cajal, Madrid, Spain. Department of Cardiology, Hospital Universitario 12 de Octubre, Madrid, Spain. Centro Integral de Enfermedades Cardiovasculares HM CIEC, HM Hospitales, Madrid, Spain. Department of Vascular Physiopathology, Hospital Nacional de Parapléjicos, SESCAM, Toledo, Spain. Department of Gastroenterology, University Hospital San Cecilio, Granada, Spain. Department of Biostatistics, Epidemiology & Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA; Department of Dermatology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA. National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA. Electronic address: nehal.mehta@nih.gov.