1. Department of Thoracic and Cardiovascular Surgery West German Heart and Vascular Center University of Duisburg‐Essen Hufelandstraße 55 45122 Essen Germany
2. Faculty of Engineering and Information Sciences University of Wollongong Northfields Ave Wollongong NSW 2522 Australia
3. School of Mechanical and Manufacturing Engineering University of New South Wales Library Rd Kensington NSW 2052 Australia
4. Department of Medicine Faculty of Medicine Imperial College London Imperial College Road London SW7 2AZ UK
5. Department of Cardiothoracic Surgery Hammersmith Hospital National Heart and Lung Institute Imperial College London 72 Du Cane Rd London W12 0HS UK