1. Robertson Centre for Biostatistics and Clinical Trials, University of Glasgow, Glasgow G12 8QQ, UK
2. National Heart & Lung Institute, Imperial College, London, UK
3. British Heart Foundation Cardiovascular Research Centre, University of Glasgow, Glasgow G12 8QQ, UK
4. Royal Brompton Hospital, London, UK
5. King’s College Hospital, London, UK
6. King’s College London, London, UK