1 Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, John Radcliffe Hospital, Headley Way, Oxford OX39DU, UK.
2 British Heart Foundation Centre of Research Excellence, Oxford, UK.
3 National Institute of Health Research (NIHR), Oxford Biomedical Research Centre, Oxford University Hospitals NHS Foundation Trust, John Radcliffe Hospital, Headley Way, Oxford OX39DU, UK.
4 Acute Vascular Imaging Centre, University of Oxford, John Radcliffe Hospital, Headley Way, Oxford OX39DU, UK.
5 Section of Cardiovascular Medicine, Department of Internal Medicine, Yale-New Haven Hospital, Yale School of Medicine, New Haven, CT, USA.