1. Department of Cardiac Surgery, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, Shandong 250014, P.R. China
2. Department of Cardiac Surgery, Yuhuangding Hospital, Yantai, Shandong 264000, P.R. China
3. Department of Clinical College of Chinese and Western Medicine, Binzhou Medical University, Yantai, Shandong 264003, P.R. China