1 Liverpool Centre for Cardiovascular Science, at University of Liverpool, Liverpool John Moores University and Liverpool Heart & Chest Hospital, Liverpool, United Kingdom.
2 Liverpool Centre for Cardiovascular Science, at University of Liverpool, Liverpool John Moores University and Liverpool Heart & Chest Hospital, Liverpool, United Kingdom; Danish Centre for Health Services Research, Department of Clinical Medicine, Aalborg University, Aalborg, Denmark; Medical University of Bialystok, Bialystok, Poland. Electronic address: [email protected].