1. Department of Vascular Surgery, General Hospital of People's Liberation Army, Beijing 100853, P.R. China
2. Department of Cardiology, Xi'an No. 3 Hospital, Xi'an, Shaanxi 710018, P.R. China
3. Department of Cardiology, People's Hospital of Yuncheng, Yuncheng, Shanxi 044000, P.R. China
4. Department of Cardiology, Xi'an Ninth Hospital, Xi'an, Shaanxi 710004, P.R. China
5. Department of Nursing, Xi'an No. 3 Hospital, Xi'an, Shaanxi 710018, P.R. China
6. Department of Cardiology, Xi Jing Hospital, Xi'an, Shaanxi 710032, P.R. China