1. Cardiovascular Medicine Center, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong 524001, P.R. China
2. Department of Orthopedics, Guangzhou Red Cross Hospital, Guangzhou, Guangdong 510000, P.R. China
3. Department of Vascular, Thyroid and Breast Surgery, Affiliated Hospital of Guangdong Medical College, Zhanjiang, Guangdong 524001, P.R. China
4. Laboratory of Cardiovascular Diseases, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong 524001, P.R. China
5. Department of Obstetrics and Gynecology, University of Wisconsin, Madison, WI 53715, USA