1. Cardiothoracic Surgery Unit, Department of Surgery, University of PortHarcourt/ University of PortHarcourt of Teaching Hospital, PortHarcourt, Rivers State, Nigeria,
2. Division of Cardiothoracic Surgery, Department of Surgery, University of Calabar Teaching Hospital, Cross Rivers State, Nigeria,
3. Cardiothoracic Surgery Unit, Department of Surgery, Usmanu Danfodiyo University/Usmanu Danfodiyo University Teaching Hospital, Sokoto State, Nigeria,
4. Division of Cardiothoracic Surgery, Department of Surgery, College of Medicine, University of Ibadan/University College Hospital, Ibadan, Oyo State, Nigeria,
5. Cardiothoracic surgery Unit, Royal Victoria Hospital, Belfast, United Kingdom,