1. Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou University, Lanzhou, Gansu 730000, P.R. China
2. Department of Ultrasonic Diagnosis, The First People's Hospital of Lanzhou, Lanzhou, Gansu 730050, P.R. China
3. Gansu Cardiovascular Institute, Lanzhou, Gansu 730050, P.R. China
4. Outpatient Department, The First People's Hospital of Lanzhou, Lanzhou, Gansu 730050, P.R. China
5. Medical Department, Shijiazhuang People's Medical College, Shijiazhuang, Hebei 050599, P.R. China
6. Anesthesiology Department, The First People's Hospital of Lanzhou, Lanzhou, Gansu 730050, P.R. China