1. Department of Cardiothoracic Surgery, Royal Stoke University Hospital , Newcastle Rd, Stoke-on-Trent ST4 6QG , United Kingdom
2. Department of Radiology, Royal Stoke University Hospital , Newcastle Rd, Stoke-on-Trent ST4 6QG , United Kingdom
3. Department of Cardiothoracic Anaesthesia, Royal Stoke University Hospital , Newcastle Rd, Stoke-on-Trent ST4 6QG , United Kingdom