[1] Heart England NHS Fdn Trust, Birmingham Heartlands Hosp, Dept Thorac Surg, Birmingham B9 5SS, W Midlands, England
[2] Coventry Univ, Sch Hlth & Life Sci, Coventry, W Midlands, England
[3] Auckland Univ Technol, Fac Hlth & Environm Studies, Sch Physiotherapy, Auckland, New Zealand
[4] St Georges Healthcare NHS Trust, Dept Cardiothorac Surg, St Georges Hosp, London, England
[5] Univ Warwick, Coventry CV4 7AL, W Midlands, England