1 Department of Cardiac Surgery, Hospital Clínico Universitario de Valladolid, Av Ramon y Cajal, Valladolid 47003, Spain. Electronic address: jbustamantemunguira@gmail.com.
2 Department of Nephrology, Hospital Virgen de la Concha, Zamora, Spain.
3 Department of Preventive Medicine, Hospital Universitario de La Princesa, Madrid, Spain.